2. Edible Coatings for Enhancing the Shelf Life of Fresh Produce during Storage ... Purdue Improved Crop Storage (PICS) Bags for Control of. Aflatoxins in Dry ...... Bruchids are mainly stored pests but the infestation starts in field before harvest. ...... crops i.e. ginger and potato is concerned, the land size has the positive.
Research Trends in Horticulture Sciences Volume - 5
Chief Editor Dr. M.L. Meena Assistant Professor, Department of Horticulture School for Agricultural Sciences and Technology, Babasaheb Bhimrao Ambedkar University, (A Central University) Lucknow, Uttar Pradesh, India
AkiNik Publications New Delhi
Published By: AkiNik Publications AkiNik Publications 169, C-11, Sector - 3, Rohini, Delhi-110085, India Toll Free (India) – 18001234070 Chief Editor: Dr. M.L. Meena The author/publisher has attempted to trace and acknowledge the materials reproduced in this publication and apologize if permission and acknowledgements to publish in this form have not been given. If any material has not been acknowledged please write and let us know so that we may rectify it. © AkiNik Publications Pages: 129 ISBN: 978-93-5335-067-3 Price: ` 595/-
Contents Chapters 1. Propagation Media
Page No. 01-13
(G. Chandrashekhar, A. Anjaneyulu and Dr. V. Yugandhar)
2. Edible Coatings for Enhancing the Shelf Life of Fresh Produce during Storage 15-30 (Pushpendra Kumar and Shruti Sethi)
3. Hermetic Storage Practices of Dolichos Bean Seeds for Control of Bruchids 31-53 (K Vanitha, P Saidaiah, Harikishan Sudini, A Geetha and M Vijaya)
4. Purdue Improved Crop Storage (PICS) Bags for Control of Aflatoxins in Dry Chillies 55-70 (K Madhusudhan Reddy, P Saidaiah, Harikishan Sudini, A Geetha and M Vijaya)
5. Scope for Organic Farming in Himalayan Region
71-89
(Vinaykumar Rachappanavar, Jeetendra Kumar Sharma, Himanshu Pandey and Kasi Indrakumar)
6. Integrated Nutrient Management in Major Seed Spices
91-114
(C.S. Karthik, A. Pariari and Shiva Kumar Udayana)
7. Generation of Novel Variants through Mutation Breeding, Tilling and Genome Editing in Vegetable Crops 115-129 (Arindam Das, Sanjay Bairagi, Koushik Saha and Sourav Mahapatra)
Chapter - 1 Propagation Media
Authors G. Chandrashekhar Department of Spices and Plantation Crops, Faculty of Horticulture, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India A. Anjaneyulu Department of Spices and Plantation Crops, Faculty of Horticulture, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India Dr. V. Yugandhar Department of Spices and Plantation Crops, Faculty of Horticulture, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India
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Chapter - 1 Propagation Media G. Chandrashekhar, A. Anjaneyulu and Dr. V. Yugandhar
Propagation media is a basic need in which the rooting of cuttings or germination of seeds takes place and also for growing stock plants. The primary role of a propagation medium is to provide support and moisture while the plant is developing. These requirements are quite different from those of a potting medium, which may have to sustain a mature or growing plant over a long period of time. Growing media being a store house of water, air and mineral supply ensuring easy germination of seed, rooting of cuttings and must be amended to provide the appropriate physical and chemical properties necessary for plant growth. Proper crop selection of medium is important. The Following Ideal Characteristics are taken into Consideration for Selection of Media 1.
It should be cheap and easily available.
2.
It should be sufficiently firm and dense to hold seeds and cuttings are placed for germination and rooting respectively.
3.
It should be cheap, slightly acidic or neutral.
4.
It should possess sufficiently high moisture retention capacity.
5.
It should be porous to drain out excess of water and permit aeration.
6.
Preferably it should not shrink when dry and increase its volume when wet.
7.
It should be free from weed seeds and. free of insects, diseases, and weed seeds.
8.
Low in silt, clay and ash content; easily stored for long periods of time without changes in physical and chemical properties; and easily handled and blended.
The various rooting media available soil, Sand, Peat, Sphagnum moss, Vermiculite, Leaf mould, saw dust, shredded bark, Pumice, Perlite, and rice straw, Important ones are given below. Page | 3
1.
Soil
Soil is a natural media for the growth of plants. They are mixtures of fragmented and partly or wholly weathered rocks and minerals, organic matter, water, and air, in greatly varying proportions, and have more or less distinct layer’s or horizons developed under the influence of climate and living organisms. Basic potting soils are usually made as a mix of materials common ingredients are actively decomposing plant material, stable plant material and mineral materials. Light and sandy soils are well suited as rooting or germinating media while loamy silty or clayey soils are unsuitable on account of poor aeration and stickiness. These soils in combination with sand, some organic matter, moss, shredded bark and peat are useful as media. 2.
Compost
Decomposing plant matter will degrade into compost, which in turn can be used to grow more plants. A naturally-occurring renewable resource, it requires little processing. As long as this decomposition is taking place (it will continue even after the compost is mature and ready for use), the material is compost. Compost has a dark earthy smell and contains nutrients that are readily available for plants. It can be mixed with the media for the better growth of the plants. 3.
Humus
Eventually compost will completely decompose and settle into its stable form which is known as humus. Humus is so stable that it can remain unchanged for hundreds, if not thousands, of years. However, since decomposition is complete humus contains little nutrient value, although it still provides for less compact soil density and general soil improvement. It can holds the plants while early growing with providing of good aeration and stability. 4.
Sand
Sand is the least expensive and most readily available large particle material. Sand consists of small rock grains of 0.05 to 2.0 mm in diameter. Quart Page | 4
sand is most useful as it is suitable for sterilization of fumigation. It has no mineral nutrients. Medium and coarse sand particles are those which provide optimum adjustments in media texture. Although sand is generally the least expensive of all inorganic amendments it is also the heaviest. This may result in prohibitive transportation costs. Sand is a valuable amendment for both potting and propagation media. 5.
Sphagnum Moss
Sphagnum peat moss is the most commonly used soilless medium. It is widely available and relatively inexpensive. Commercial sphagnum moss is the dehydrated remains of acid bag plants which is acidic, sterile, light in weight and has high water holding capacity being able to absorb water up to 10 - 20 times of its weight. It contains small amount of minerals. This is attributed to the large groups of water holding cells, characteristic of the genus. Drainage and aeration are improved in heavier soils while moisture and nutrient retention are increased in lighter soils. Sphagnum moss contains specific fungistatic substances which accounts for its ability to inhibit damping-off of seedlings. 6.
Vermiculite
Vermiculite is a micacious mineral produced by heating to approximately 745oC. It is light in weight (25 - 45 kg/cu ft.) with good mineral supply and able to absorb fuanity of water i.e. 13.5 to 18 liters/cu ft. Generally particles of 2 - 3 mm are move useful. Vermiculite has excellent ex-change and buffering capacities as well as the ability to supply potassium and magnesium. Although vermiculite is less durable than sand and perlite, its chemical and physical properties are very desirable for container media. The expanded, plate-like particles which are formed have a very high water holding capacity and aid in aeration and drainage. One of the major shortcomings of vermiculite is its poor physical stability after wetting. If not handled properly, vermiculite compacts and loses its ability to hold air. 7.
Leaf Mould
Layers of leaves and soil are composted together with small amounts of nitrogenous compounds for approximately 12 to 18 months. The use of leaf mold can effectively improve the aeration, drainage and water holding properties of a growing media. Page | 5
Although these materials are readily available at low cost, leaf mold is not extensively used in container production maple, oak, and sycamore are among the principle leaf types suitable for the preparation of leaf mold. 8.
Saw Dust
The species of tree from which sawdust is derived largely determines its quality and value for use in a growing media. Several sawdusts, such as walnut and non-composted redwood, are known to have direct phytotoxic effects. However, the C: N of sawdust is such that it is not readily decomposed. The high cellulose and lignin content along with insufficient N supplies creates depletion problems which can severely restrict plant growth. However supplemental applications of nitrogen can reduce this problem. 9.
Pumice
This is derived from grey or white volcanic rock consisting of spongy like gaps. Pumice is a very lightweight volcanic rock that is used sometimes to increase aeration and drainage in potting mixes. It is sometimes used in field plantings or in container cuttings. Pumice has a fair water holding capacity. It is not heat treated and so is not sterile. 10. Perlite Perlite is a silicous mineral of volcanic origin. Perlite is a volcanic rock that is heated and expanded to become a lightweight material. Because it is heated to 1400-1800F, it is sterile. The grades used in container media are first crushed and then heated until the vaporization of combined water expands it to a light powdery substance. Lightness and uniformity make perlite very useful for increasing aeration and drainage. Perlite is very dusty when dry and has a tendency to float to the top of a container during irrigation. It has also been shown that perlite contains potentially toxic levels of fluorine. Although costs are moderate, perlite is an effective amendment for growing media. 11. Pine Bark Composted pine bark may be substituted, in part, for peat moss. Bark particles have a relative
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high cation exchange capacity, while most particles have internal waterholding capacity. The large moisture content of fresh bark makes it heavy. Once bark dries below 35 percent of its total water-holding capacity, it becomes difficult to rewet. 12. Peat and Peat-Like Materials Peat moss is dead fibrous material that forms when mosses and other living material decompose in bogs. It takes several millennia for peat moss to form, so it’s not a renewable resource, but it is great for acid loving plants like blueberries and camellias. Peat moss is formed by the accumulation of plant materials in poorly drained areas. The type of plant material and degree of decomposition largely determine its value for use in a growing medium. Although the composition of different peat deposits vary widely, distinct categories may be identified: Hypnaceous moss: This type of peat consists of the partially decomposed remains of hyprum, polytrichum and other mosses of the Hypanaceae family. Although it decomposes more rapidly than some other peat types, it is suitable for media use. Many of the peat deposits in the Northern United States are Hypnaceous. Reed and Sedge: are peats derived from the moderately decomposed remains of rushes, coarse grasses, sedges, reeds and similar plants. These fine textured materials are generally less acid and contain relatively few fibrous particles. The rapid rate of decomposition, fine particle size and insufficient fiber content make reed and sedge peats unsatisfactory for media use. 13. Coconut Coir A byproduct of processing coconut husks is known as coir dust, coco peat, or simply coir. This material has proven to be an excellent organic component for container growing media and is readily available in some tropical locales. Coconut coir has many desirable qualities: high water-holding capacity; excellent drainage; absence of weeds and pathogens; physical resiliency slow decomposition; easy wettability; and acceptable levels of pH, cation exchange capacity, and electrical conductivity. Coir is very similar to peat in appearance and structure, and, like peat, physical and chemical properties of coir can vary widely from source to source (Evans et al., 1996 and Noguera et al., 2000). Coir is low in nitrogen, calcium, and magnesium but can be relatively high in phosphorus and potassium. Page | 7
14. Rice Hulls Rice hulls are the sheaths of rice grains, a waste product of rice processing (Landis and Morgan 2009). Rice hulls or husks have been used as a component of potting medium with locally obtained peat for many years in Indonesia (Miller and Jones 1995). Several nurseries have used composted, screened, and hammer-milled rice hulls in place of composted bark (Landis and Morgan 2009). Table 1: Comparison of potting mix materials Material Soil
Cation pH Sterile Water Holding Exchange Values (y/n) Capacity Poor
4.5-6.0
No
Poor
Weight
Cost
Heavy
Low
Lightweight
Medi um
Sphagnum peat moss
Fair
3.5-4.0
Yes
High
Bark
High
4.0-5.0
No
Medium
Poor
4.5-6.0
Yes
Poor
Poor to Fair 4.5-6.0
No
Medium
Very Lightweight High
Sand Pumice
Medium to Heavy Low Heavy
Low
Perlite
None
6.0-8.0
Yes
Poor
Very Lightweight High
Vermiculite
High
4.0-5.0
Yes
Good
Very Lightweight High
Compost
High
4.5-6.0
No
good
Medium
Low
The development of a healthy, fibrous root system needs a media with these good physical properties. Any nutrient or chemical deficiencies can be compensated for with additions of fertilizers and amendments. Materials generally used to improve the physical properties of media are inert materials, such as sand, vermiculite, perlite, volcanic cinders, and coarse organic residues. These inert materials improve drainage and aeration in the media. Physical Properties Water-Holding Capacity Micropores absorb water and hold it against the pull of gravity until plants can use it. The water-holding capacity of a medium is defined as the percentage of total pore space that remains filled with water after gravity drainage. A good growing medium has a high water-holding capacity but also contains enough macropores to allow excess water to drain away and prevent waterlogging. Water-holding capacity varies by the types and sizes of the growing medium ingredients. For example, a peat moss particle will Page | 8
hold much more water than a similarly sized piece of pumice. The degree of compaction is also extremely important. When growing medium particles are damaged during mixing or compacted when the containers are filled, the percentage of macropores is severely reduced. Overmixed or compacted media will hold too much water and roots will suffocate. Finally, the height of the container affects the water-holding capacity; a certain amount of water will always remain in the bottom of the container. When filled with the same medium, short containers will have a higher percentage of waterlogging than taller ones. Aeration The percentage of pore space that remains filled with air after excess water has drained away is known as aeration. As we have already discussed, oxygen for good healthy roots is supplied through the larger macropores, which also allow the carbon dioxide from respiration to dissipate. A good growing medium, especially for rooting cuttings, contains a high percentage of macropores. (Example sand is calcium carbonate (agricultural lime) and should not be used where high pH is undesirable or where plants remain in the containers for long periods, because the sand dissolves and results in poor aeration. Vermiculite is good for short-term use, but eventually it collapses and causes poor aeration in the media. Perlite is a good material with considerable porosity within each particle). Porosity Porosity is one of the most important physical properties in a growing media because it determines the space available in a container for air (aeration), water, and root growth (Liegel and Venator, 1987). Aeration is important because the root system "breathes" (exchanges oxygen and carbon dioxide) in the large, air-filled pores (macropores). Poor aeration will adversely affect root form (morphology) and structure (physiology) and will lead to decreased seedling vigor (Scagel and Davis, 1988).The total porosity of a growing medium is the sum of the space in the macropores and micropores; plants need both. A growing medium composed primarily of large particles will have more aeration and less water-holding capacity than a medium of smaller particles, which will have less aeration and more waterholding capacity. Either of these media would restrict plant growth. Plants growing in a medium with all large particles would dry out too quickly, and those growing in a medium with all small particles would suffer from waterlogging. A good growing medium will contain a mixture of ingredients with different particle sizes and characteristics.
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Bulk Density Media bulk density is the weight per volume and varies with the inherent bulk density of its ingredients and how much they are compressed. An ideal growing medium is light weight enough to facilitate handling and shipping while still having enough weight to provide physical support. For a given container type and growing medium, excessive bulk density indicates compaction. Bulk density and porosity are inversely related; when bulk density increases, porosity decreases. Even a very porous growing medium can be ruined if it is compressed when the containers are filled. Chemical Properties Fertility Rapidly growing young plants use up the stored nutrients in their seeds soon after emergence. Thereafter, plants must rely on the growing medium to meet their increasing demands for mineral nutrients. Plant Nutrition and Fertilization, many container nursery managers prefer media with inherently low fertility (for example, peat-vermiculite) to discourage damping-off during the establishment phase and add soluble fertilizers to media throughout the remainder of the growing season. If fertilizers are difficult to obtain or cost prohibitive, organic amendments such as manure or compost can be included in the growing medium. Some plants grow better under low fertilization; in addition, beneficial microorganisms, such as mycorrhizal fungi, sometimes require low fertility to become established on plant roots. pH The pH of growing medium is a measure of its relative acidity or alkalinity. pH values range from 0 to 14; those below 7 are acidic and those above 7 are alkaline. Most native plants tend to grow best at pH levels between 5.5 and 6.5, although some species are tolerant of higher or lower pH levels. The main effect of pH on plant growth is its control on nutrient availability. For general purpose growing media, the ideal pH range is between 5.2 – 6.2 with a target of 5.8 when saturated. When pH levels are not within the desired range, nutrients either become unavailable or toxic and microorganisms in the potting media will be affected. Regardless, pH is easily controlled by chemical additives (e.g. lime or sulfur). For seed germination and rooting of cuttings, the desired pH range will be slightly lower, between 5.0 – 6.0, with a target wet-out at 5.6. This pH range is slightly lower since pH can tend to rise during use from minimal fertilizer applications and water alkalinity of irrigation water from constant Page | 10
misting. For example, phosphorus availability drops at extreme pH values because phosphorus binds with iron and aluminum at low pH levels and with calcium at high pH levels. The availability of micronutrients, such as iron, is even more affected by pH. Iron chlorosis, caused by high pH, is one of the most common nutrient deficiencies of nursery stock. Exceptionally high or low pH levels also affect the abundance of pathogens and beneficial microorganisms. For example, low pH can predispose young plants to damping-off fungi. Cation Exchange Capacity (CEC) CEC refers to the ability of a growing medium to hold positively charged ions. Because most growing media are inherently infertile, CEC is a very important consideration. In the growing medium, plant roots exchange excess charged ions for charged nutrient ions, and then these nutrients are transported to the foliage, where they are used for growth and development. Because the CEC of a growing medium reflects its nutrient storage capacity, it provides an indication of how often fertilization will be required. Because nutrient leaching occurs during irrigation, container nurseries prefer a growing medium with a very high CEC. A mixture's CEC cannot be determined outside of a laboratory, but as a general rule, the greater the addition of organic matter or compost the higher the CEC of the mix. Table 2: Different chemical and physical properties of some common materials used to growing media Component
Bulk Density
Sphagnum peat moss Bark Coir Sawdust Rice hulls Compost
Very low Low Low Low Low Variable
Vermiculite Perlite Sand Pumice
Very low Very low Very high Low
Porosity: Porosity: Water Air Organic Ingredients Very high High Low Very high High High High Moderate Low Moderate Variable Variable Inorganic Ingredients Very high High High High Moderate Very low Low High
pH
Cation Exchange Capacity
3 to 4 3 to 6 6 to 7 3 to 6 5 to 6 6 to 8
Very high High Low Low Low High
6 to 8 6 to 8 Variable 6 to 8
High Very low Low Low
Field Soil Field soil Variable Variable Variable Variable Variable Source: Buamscha and Altland (2005), Johnson (1968), Lovelace and Kuczmarski (1994), and Newman (2007). Page | 11
Biological Properties Growing media may contain pathogenic bacteria or fungi. Growing media ingredients that may contain pathogens can be treated with sterilization or pasteurization before use, as described later in this chapter. Organic-based growing media are preferred in nurseries because they are generally pest free. Although peat moss is not technically sterile, it does not contain pathogens or weed seeds when obtained from reliable sources. Vermiculite and perlite are rendered completely sterile during manufacturing, when they are exposed to temperatures as high as 1,832 °F (1,000°C). Well-prepared composts are generally pest free because sustained, elevated temperatures during composting kill most pathogens. Another benefit of composting is that beneficial microorganisms increase in the final stages of the process. Composted bark of some tree species, for example, contains microbes that suppress common fungal pathogens and nematodes. References 1. 2.
3.
4. 5. 6. 7.
8.
Buamscha G, Altland J. Pumice and the Oregon nursery industry. Digger. 2005; 49(6):18-27. Evans MR, Konduru S, Stamps RH. Source variation in physical and chemical properties of coconut coir dust. Hort-Science. 1996; 31:96567. Ingram, Dewayne L. Bulletin 241, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: August 1991. Revised: May, 1993. Johnson P. Horticultural and agricultural uses of sawdust and soil amendments. National City, CA: Paul Johnson, 1968, 46. Kester Dale E. Hartmann and Kester’s plant propagation: principles and practices, 7th edition. Prentice Hall, 2002. Kuepper George. Potting Mixes for Certified Organic Production. September, 2004. Landis TD, Morgan N. Growing media alternatives for forest and native plant nurseries. In: Dumroese RK, Riley LE, tech. coords. National proceedings: forest and conservation nursery associations. Proc. RMRS Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 2008, 2009, 26-31, 58. Liegel LH, Venator CR. A technical guide for forest nursery management in the Caribbean and Latin America. General Technical Report S0-67. New Orleans, LA: USDA Forest Service, Southern Forest Experiment Station, 1987. Page | 12
9.
10. 11.
12. 13.
14.
15. 16.
17.
Lovelace W, Kuczmarski D. The use of composted rice hulls in rooting and potting media. International Plant Propagators’ Society, Combined Proceedings. 1994; 42:449-50. Meche Michelle. Hort 202, General Horticulture Lab 7. Copyright D.W. Reed, TAMU. Miller JH, Jones N. Organic and compost-based growing media for tree seedling nurseries. World Bank Tech. Forestry Series. Washington, DC: The World Bank, 1995, 75, 264. Newman J. Core facts about coir. Greenhouse Management and Production. 2007; 27(2):57. Noguera P, Abad M, Noguers V, Puchades R, Maquieira A. Coconut coir waste: a new and environmentally friendly peat substitute. Acta Horticulture. 2000; 517:279-86. Scagel RK, Davis GA. Recommendations and alternative growing media for use in containerized nursery production of conifers: some physical and chemical properties of media and amendments, 1988, 8-11, Spokane Community College. Greenhouse Nursery Management. Ag 108. Superior Soil Supplements. Ammendments. Vancouver BC. Gen. Tech. Rep. RM-167 Fort Collins, CO: USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, 1988, 60-65. Wade W. McCall. Basic characteristics of media for container-grown plants. General home garden series. 10, 1980.
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Chapter - 2 Edible Coatings for Enhancing the Shelf Life of Fresh Produce during Storage
Authors Pushpendra Kumar Division of Food Science and Postharvest Technology, IARI, New Delhi, India Shruti Sethi Division of Food Science and Postharvest Technology, IARI, New Delhi, India
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Chapter - 2 Edible Coatings for Enhancing the Shelf Life of Fresh Produce during Storage Pushpendra Kumar and Shruti Sethi
Abstract The application of coatings is one of the most innovative methods to enhance the shelf life of fruits by acting as a moisture and gas barrier and having a similar impact as the storage under modified atmosphere packaging (MAP). Edible coatings on fruits can furnish an substitute to modified atmospheric storage by controlling quality changes and slowing down of quantity losses through modification and control of the internal atmosphere of the individual commodity. This chapter elucidated the role of edible coatings for extending shelf life and preserving quality of fruits. The chapter also described the action of edible coatings and methods of applying coatings. Ultimately the chapter discussed the recent findings for further improving the performance and function of edible coatings for fresh produce during storage. Keywords: Edible coating; fresh fruit; modified atmospheric packaging; shelf life; properties Introduction Edible coating has been describe as a thin layer of edible materials which can be consumed with the products, formed on foods and provides a barrier to oxygen, moisture and solute movement for food, to serve as a carrier of food additives and ingredients or to provide mechanical and microbial protection. Preservation of fruits is a major concern for the fresh produce industry. Various technologies are available to enhance the shelf life of fresh fruits and to prevent postharvest losses such as controlled atmosphere and modified atmospheric packaging (MAP) is popular. Coatings are a simple technology by which fresh fruits can be physically protected and have their respiration and also ripening regulated as with passive modified atmospheric packaging (MAP). The elongation of shelf life of food is mainly depending on three major factors such as reduction in the physiological process, reduction in Page | 17
desiccation and reduction in the microbial growth. Coatings on fruits can provide a substitute to modified atmosphere storage by controlling quantity losses and quality changes through modification and control of the internal atmosphere of the individual fresh fruit. Edible materials may contribute to enhance the storage life of fresh fruits by decreasing solute and moisture migration, respiration, gas exchange and oxidative reaction rates as well as by decreasing and suppressing the physiological disorders. It has a high capability to carry active ingredients such as flavours, nutrients, browning inhibitors, colorants and antimicrobial compounds that can enhance produce storage life and reduce the risk of microbial growth on surface of food. Moreover, another important benefit of edible coatings is the decreasing of synthetic packaging waste because these coatings are composed of biodegradable material. Over the last decades the use of coatings to extend the storage life and improve the quality of fresh fruits has been receiving increased attention. Properties of Edible Coatings
It should be water resistant.
Improve glossiness, improve mechanical handling properties, retain volatile flavour compounds and carry active agents.
Never interfere with the fruits quality.
It should not deplete O2 and build up excessive CO2.
Reduce water vapour permeability.
Non-sticky, easily performance.
Economical.
emulsifiable
and
have
efficient
drying
Application of Edible Coatings Edible coatings are applied directly on the fruits surface; the thin film is formed on the product. Edible coatings may be applied by spraying, dipping, brushing and foam application. In dip method coating, food is directly dipped into the composite coating formulations, then removed and allowed to dry. Edible coating by spraying' is the conventional method generally used in most of the cases. Foam application method is used for coating emulsions. Mechanisms of Edible Coatings to Enhance the Storage Life of Fruit It is noted that fruits continue to respire even after detached from the plant, resulting utilize up all the O2 within the commodity which is not replaced as immediate as by edible coating and produces CO2 which Page | 18
accumulates within the commodity because it cannot escape as easily through edible coating. Ultimately, the produce will shift to partial anaerobic respiration that requires less O2. With less oxygen, the production of C2H4 which enhance the ripening process is retarded and the loss of moisture is reduced. Thus, the fruits remain fresh, firm and nutritious for longer duration and their shelf life almost doubles. The natural barrier on fruits and the amount and type of coating will affect the extent to which the internal atmosphere are modified and the level of reduction in moisture loss. Advantages of Edible Coatings
Reduces the rate of respiration and ethylene evaluation.
Improves external appearance of fruits surface by giving additional shine.
Reduces moisture loss and keep the fruits firm.
Prevents storage disorders and chilling injuries.
Act as barrier to free gas exchange.
Provides a carrier for postharvest chemical treatments.
Minimizes the use of synthetic packaging material.
Encapsulates aroma compounds, pigments, antioxidants, ions that stop browning reactions and nutritional substances such as vitamins.
The present chapter is an attempt to compile a comprehensive review by critically examining scientific literature pertaining to the physical, physiological and biochemical changes in fruits in response to postharvest treatments with surface coatings. Nevertheless, this chapter would provide valuable insights into what has already been achieved in fresh fruits. Influence of Edible Coatings on Physical Attributes Edible Coatings Affect the Physiological Loss in Weight Physiological loss in weight is an important parameter which affects the freshness of a fruit, cause flesh softening, fruits ripening and senescence because of C2H4 production and other metabolic reactions. The primary mechanism of moisture loss from the fruits is by vapour-phase diffusion driven by a gradient of water vapour pressure (WVP) at different locations. The moisture permeability and thickness of the barrier of edible coatings is important factors for the mass transfer rate. Decrease in weight loss due to the respiration because of carbon atom losses from the fruits in each cycle. Zhou et al. (2008) worked with Huanghua pears cultivar Huanghua. Shellac, SemperfreshTM and carboxymethyl chitosan edible coatings were Page | 19
used during cold storage. The pear fruits coated with shellac and SemperfreshTM showed reduced weight loss as compared to control fruits and chitosan coated fruit. All the edible coatings decreased moisture loss in fruits during storage and no shrivelling was recorded in treatment. The greater physiological loss in weight was observed in carboxymethyl cellulose (CMC) and SemperfreshTM edible coatings because they are more hydrophilic than the shellac based edible coating. It was clearly observed that the reduced moisture loss in shellac coated samples contributed for maintaining better quality of pear fruits during cold storage. Plums cv. ‘Autumn Giant’ was coated with hydroxypropyl methylcellulose–lipid composite edible coatings by Perez-Gago et al. (2003). The edible coatings consist of beeswax and shellac. It was revealed that the weight loss of coated plum fruits reduced only at the high lipid content. Firmness was not influenced by coating after short term storage at 20°C. However, the plums stored at 20°C for prolonged, the edible coatings significantly decreased the softening and internal breakdown compared with control samples. Eum et al. (2009) reported that the plums have a natural wax layer which acts as a barrier to gas diffusion and water loss and protects the fruits against environmental stresses. Physiological loss in weight was higher in uncoated and versasheen without sorbitol coated fruits compared to the versasheen with sorbitol coated samples. At the termination of experiment the uncoated and versasheen without sorbitol samples recorded higher weight loss whereas the versasheen with sorbitol coated fruits had a reduced weight loss. The enhanced moisture loss could be due to the higher respiration rate. Navarro-Tarazaga et al. (2011) coated the plums cv. Angeleno with hydroxypropyl methylcellulose (HPMC) based edible coatings containing beeswax and reported that the coating significantly decreased the moisture loss in comparison to the uncoated and hydroxypropyl methylcellulose coated fruits with no beeswax. Finally, they suggested that in order to enhance moisture barrier properties of edible coatings must have a hydrophobic compound. Valero et al. (2013) reported that alginate coating significantly reduced the moisture loss for all plum tested cultivars. They observe that the physiological loss in weight in fruits is due to the transpiration process which is measured by the gradient of water vapour pressure (WVP) between the fruits and the surrounding air. Cuticle and epidermal cell layer reduced the transpiration. As epidermis and cuticle structure and fruits surface/volume ratio are varied among plum fruits varieties, variations in moisture loss were recorded in control fruits depending on varieties. In addition, coatings act as
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an extra layer which coats the stomata leading to a reduction in transpiration and finally decrease in moisture loss. Duan et al. (2011) worked on fresh blueberries cv. Duke and Elliott and applied SemperfreshTM (1%), acid soluble chitosan (2%), water soluble chitosan (3%), water soluble chitosan 3% + sodium alginate 2%. They reported that SemperfreshTM coating significantly reduced moisture loss. Malmiri et al. (2011) worked on ‘Berangan’ banana cultivar. Banana fruits coated with chitosan (0.5-2.5% w/w) with glycerol (0 – 2% w/v) and stored at 26°C along with 40-50% Relative humidity for 10 d. They observed a significant reduction in the loss of weight of banana at low concentrations of glycerol and an increase in the chitosan concentration. Velickova et al. (2013) worked with strawberry cv. Camarosa. The strawberry fruits coated with chitosan and bee wax coatings and three layers coating composite coating consisting of beeswax-chitosan-beeswax followed by storage at 20°C and 35-40% Relative Humidity. It was evidenced that the chitosan coatings prolonged the storage life of strawberry fruits for 7 d at 20°C and 53% RH and retard the senescence process compared to the control strawberry samples whereas composite coating revealed beneficial effect against fungal infection and decrease in moisture loss. Edible Coatings Affect the Fruits Decay Singh et al. (2009) conducted the experiment to investigate the influence of sodium carbonate and sodium bicarbonate on improving the bio-efficacy of Debaryomyces hansenii for reducing the incidence of blue mould rot of apple fruits caused by Penicillium expansum. It was reported that the blue mould incidence reduced in sodium bicarbonate treatment combination after 15 d of inoculation at 25 ºC and the minimum infected area was observed in D. hansenii + sodium carbonate treated samples. Apples treated with sodium bicarbonate + D. hansenii also recorded a minimum spoilage than control samples after 42 d of storage at ambient temperature. Han et al. (2004) studied the impact of chitosan (2%) edible coatings to enhance the shelf life and nutritional value of strawberry and red raspberry fruits stored at 2oC and 88% RH for 3 weeks and at -23oC for 6 months. It was reported that the decay incidence of treated strawberries and red raspberries fruits stored at 2oC and 88% RH were decreased significantly compared to control fruits. El-Anany et al. (2009) studied the efficacy of jojoba wax, soybean gum, Arabic gum and glycerol as coatings on the quality and shelf-life of Anna apple during low temperature storage at 0°C and 90-95% RH. It was found that coated apple fruits significantly delayed Page | 21
the ripening process and therefore decayed slowly as compared to uncoated fruits. Another study was conducted by Maqbool et al. (2010) on banana fruits with use of chitosan edible coating. It was recorded that the chitosan reduced the growth of Colletotrichum musae as compared to the uncoated samples. Goncalves et al. (2010) reported that the use of carnauba wax (4.5%) significantly decreased the brown rot in plum and nectarine fruits in compared to the uncoated samples. The application of edible coating on surface of fruits which acts as a physical barrier around the fruits that prevents entry of pathogen and modified a atmosphere around the fruits and direct impact of the wax to the pathogens. Vargas et al. (2006) worked on strawberries cv. Camarosa. The chitosan edible coating (1%) with oleic acid was applied on strawberry fruits which were then stored at 4°C for 10 d. it was evidenced that the edible coating inhibit fungal infection in comparison to the uncoated samples which started to decay from the beginning of storage. At the termination of storage period the infection percentage in treated strawberry samples was below 50% whereas all uncoated strawberry samples showed visible signs of fungal infection. Wang and Gao (2013) observed that the decay of strawberry coated fruits with chitosan decreased significantly. The impact of chitosan edible coating in inhibiting the growth of microbial was more evident and clear for longer storage and at higher storage temperature. Edible Coatings Affect the Fruits Firmness Generally fruits firmness decreases as progression in the storage period. Malmiri et al. (2011) studied the effect of chitosan edible coating on fruits firmness of banana and clearly reported that with an increase in chitosan concentration there was a beneficial effect on firmness retention. It has been reported by Barman et al. (2011) that the use of Putrescine + carnauba wax coatings retained maximum firmness in comparison to the uncoated samples. Higher retention of firmness during storage might be due to reduced the dehydration and degradation of cell wall components. Yang et al. (2007) reported that the disassembly cell wall and middle lamella structures of fruits may be due to the changes in texture during storage. Hardness in climacteric fruits during ripening is generally associated to degradation of the cell wall and loss of turgor pressure in the cells reduced by moisture loss (Lohani et al., 2004; Khin et al., 2007). Edible coating may the preserve the hardness of fruits by decreasing moisture loss. Edible coating may also restrict the activities of pectin degrading enzymes which related to softening of fruits by inhibiting the rate of metabolic processes during senescence (Conforti and Zinck, 2002; Zhou et al., 2008). Earlier studies have also reported a similar Page | 22
performance of inhibiting softening by SemperfreshTM coating in quinces (Yurdugul, 2005), shellac coating in apples (Bai et al., 2002) and by chitosan edible coating in citrus fruits (Chien et al., 2007). Zhou et al. (2008) reported that the shellac and carboxy methyl chitosan coatings were more efficient in decreasing changes in the texture than SemperfreshTM coating during storage. Valero et al. (2013) coated four plum (Prunus salicina Lindl.) cultivars namely Blackamber, Golden Globe, Larry Ann and Songold with alginate 1% and 3% w/v. They observed that the softening process was rapid when plum fruits were transferred to 20oC after low temperature storage. It is evidenced that the alginate coatings slowed down the softening process for plums either during low temperature storage or subsequent shelf life and the 3% alginate coating more effective in comparison to 1%. The changes in cell wall composition particularly mechanical strength and cell-to-cell adhesion are the important attributes contributing to firmness losses during fruits ontree ripening or after harvesting, the activity of hydrolysing enzymes enhanced by C2H4 in climacteric fruits. In plums, the cell wall degrading enzymes are pectin methyl esterase (PME), polygalacturonase (PG), galactosidase and 1, 4-d-glucanase/glycosidase. Thus, they infer that the reduction of C2H4 production reported in alginate coated plum fruits could be responsible for their lower softening process with respect to uncoated fruits. Edible Coatings Affect the Peel Colour Colour is important fruits quality parameter which influences the consumer appeal as well as internal condition. Yaman and Bayoundurlc (2002) reported that SemperfreshTM coating were effective in improving lightness in sweet cherry. Han et al. (2004) studied red raspberries and observe that the chitosan edible coating alone showed the best control of colour of fruits during storage. Ergun et al. (2005) reported that Mamey sapote fruits coated with wax and 1-MCP had a good colour than that of untreated fruit. Eum et al. (2009) investigated that the surface colour of ‘Sapphire’ plums changed from green to red and dark black storage at 20°C and 85% RH. The colour changes of plum fruits were identified by hue angle and correlated to the chlorophyll as well as anthocyanin alterations. It was found that the L* value was not different in all sample treatment. However, during the storage period the value was decreased. The diminishing of a* value and hue indicated that the plum fruits became darker and redder during ripening and senescence. Barman et al. (2011) also found that the changes of colour of peel during maturation in pomegranate fruits were related with the synthesis of anthocyanin. It was investigated that control fruits revealed significantly decrease of hue and increase in chroma value as compared to treated pomegranate fruit. The higher chroma and lower hue values of Page | 23
putrescine + carnauba wax coated fruits attributed to delayed process of maturation in comparison to uncoated fruit. Valero et al. (2013) coated four plum (Prunus salicina Lindl.) cultivars ‘Songold’ ‘Blackamber’, ‘Golden Globe’ and ‘Larry Ann’ with alginate 1% and 3% w/v. They found that colour of skin changed during storage in all plum cultivars, to deep yellow in ‘Golden Globe’ and ‘Songold’ and to dark purple in ‘Blackamber’ and ‘Larry Ann’. The colour changes were inhibited by 1% alginate and 3% alginate coatings without major differences between them except for ‘Golden Globe’ plum fruits and 3% alginate was the most effective. Colour changes were lower during low temperature storage than after the shelf life periods. Influence of Edible Coatings on Physiological Attributes Edible Coatings Affect the Respiration and Ethylene Production As the progression of storage period the respiration rate of fruits has been increases. Zhou et al. (2008) worked with Huanghua pears cv. Huanghua. Edible coatings oatings used were SemperfreshTM, shellac and carboxymethyl chitosan during cold storage. The edible coatings were applied as SemperfreshTM 1 gm/100 ml water, shellac 14.3 gm/100 ml water and CMC 2 g/100 mL water. The results of entire the storage period revealed that the respiration rates of treated pear fruits significantly reduced. Earlier studies indicated that the gas exchange between the atmosphere and fruits occurs partly by diffusion through open pores and partly by permeation through skin of fruits (Bai et al., 2002) and which take place mainly through pores (Amarante et al., 2001). All the applied edible coating reduced the respiration rate of pear fruits which might be due to the partial or complete blockage of pores. Low levels of O2 in treated pear fruits suppressed the cytochrome oxidase activity and played a important role in the restriction of activities of ascorbic acid oxidase, glycolic acid oxidase and polyphenol oxidase. These edible coatings treatment associated to the inhibition of vital activities thus preserving the Huanghua pears quality during storage. Shellac coating was reported to be more effective in inhibiting the respiration rate of fruits might be due to the shellac coating is more effective in reducing the gas exchange between fruits and the atmosphere during storage. In carnauba wax coated fruits the low respiration rate related due to the reduced gas interchange and availability of low O2 to the tissues of fruits for respiration. Further, as reported by Barman et al. (2011) the effect of combined application of Putrescine + carnauba wax in pomegranate fruits proved better because of anti-senescence and barrier properties of Putrescine and carnauba
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wax, respectively. It was also reported that C2H4 evaluation of fruits was suppressed when they were coated with Putrescine and carnauba wax alone or in combination. Eum et al. (2009) worked on plum cv. Sapphire and applied carbohydrate based Versasheen 5% with sorbitol as plasticizer. The treated plum fruits were stored at 20°C with 85% Relative humidity for 8 d. The edible coating of versasheen without sorbitol exhibits a higher C2H4 production than control and versasheen with sorbitol during 3 d of storage at 20°C. Earlier, Perez-Gago et al. (2003) showed that the impact of edible coating on the C2H4 production depended on the produce and type of coating materials. The C2H4 production of apple fruits treated with polysaccharidebased coating was decreased whereas those for plums treated with HPMC it was not affected. Valero et al. (2013) coated four plum (Prunus salicina Lindl.) cultivars, namely, ‘Songold’, ‘Larry Ann’, ‘Golden Globe’ and ‘Blackamber’ with alginate 1% and 3%. Observations were recorded after 7, 14, 21, 28 and 35 d at 2°C and after period of 3 d at 20°C (shelf life). It was reported that edible coatings significantly reduced the ethylene production for all plum cultivars especially in 3% alginate coated plum fruits in which the climacteric peak of C2H4 production was highly suppressed. Influence of Edible Coatings on Biochemical and Quality Attributes Edible Coatings Affect the Antioxidant Activity and Phenol Content Sánchez-González et al. (2011) worked on edible coatings based on hydroxypropyl methyl cellulose (HPMC) and chitosan with and without bergamot essential oil on grape fruits cv. Muscatel. They reported that the antioxidant capacity of the grape samples rapidly increased during the first 3 d of storage at 1-2oC and 85-90% RH but afterwards there was hardly any increase of the treatment which they related to the production of Maillard compounds with the appearance of the brown colour. It was also observed in grape fruits during storage that the formation of antioxidant compounds may be resultant of enzymatic browning by the increasing activities of polyphenol oxidase and peroxidase. No significant differences showed for the phenol content in grape samples. The content of phenol rapidly significantly reduced from 121 to 82 mg/100 g during the initial 3 d of cold storage for all the treatments regardless of the edible coating applied and a continuously slow fruits decay occurred afterwards (68 mg/100 g in the uncoated) as has been earlier recorded in grape fruits (Valero et al., 2006; Meng et al., 2008) and in other non climateric fruits such as strawberry (Ferreyra et al., 2007). Page | 25
The phenylalanine ammonialyase (PAL) activity is a important factor in the phenolic accumulation in grape fruits and this activity reduced during maturation and postharvest stages (Meng et al., 2008). Edible Coatings Affect the Anthocyanins Content Wang and Gao (2013) reported that pelargonidin 3-glucoside was the main anthocyanin in strawberries with an initial content of 424.5 mg/g FW. In chitosan coated fruits the total anthocyanins also increased but at a slower pace and not revealed a decreasing trend at the later part of the storage in comparison to the uncoated samples. Therefore, chitosan-coated samples preserved higher anthocyanins content in comparison to the control fruits. It was evidenced from this study that the anthocyanin contents and total phenolic generally increased with increasing temperature. Cordenunsi et al. (2005) reported that anthocyanins increases during storage with the increasing temperature. These results showed that there was still anthocyanin biosynthesis after harvesting and by the end of storage. Similarly, Fan et al. (2009) found that the strawberry fruits coated with alginate at 2% exhibit the lower increases in total anthocyanins than uncoated samples. Edible Coatings Affect the Lipid Peroxidation/Malondialadehyde Content The increase of malondialdehyde content which is a product of the oxidation of polyunsaturated fatty acids is a measure for formation of active oxygen specie that results in oxidative stress leading to peroxidative damage in the membranes (Shao et al., 2005). Controlled atmosphere (CA) storage has been known to inhibit the increase in TBARS concentration under optimal conditions in pear (Larrigaudière et al., 2001). Eum et al. (2009) worked on plum cultivar Sapphire and used carbohydrate based edible coating, versasheen 5% with sorbitol as plasticizer. The treated plum samples were stored at 20°C with 85% Relative Humidity for eight d. They recorded differences in malondialdehyde (MDA) content between control and versasheen coated with and without sorbitol value after 4 d of storage at room temperature. It was observed that the production of malondialdehyde (MDA) in versasheen coated fruits reached the same level as for control samples after 4 d of storage. The treatment with and without sorbitol not significantly affect the malondialdehyde (MDA) content. Yu et al. (2012) investigated that the MDA contents of all the samples of jujube constantly increased during the entire period of storage. No significant difference was reported in the malondialdehyde (MDA) content between the jujubes coated with chitosan + nano silicon dioxide and chitosan Page | 26
alone. The chitosan + nano silicon dioxide edible coating also delayed the increase of malondialdehyde (MDA) content in jujube. After 32 d of storage the MDA content of the jujube coated with chitosan + nano silicon dioxide was 0.38 µmol/g which was lower than that of the jujube coated with chitosan alone. It was recorded that the MDA content of the jujube coated with chitosan + nano silicon dioxide was the lower might be due to the higher activities of superoxide dismutase, peroxidase and chloramphenicol acetyltransferase could quickly eliminate the free radical. Thus, the damage caused by the free radical to the cytoplasmic membrane by was reduced. References 1.
Amarante C, Banks NH, Ganesh S. Relationship between character of skin cover of coated pears and permeance to water vapour and gases. Postharvest Biology and Technolology. 2001; 21:291-301.
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Barman K, Asrey R, Pal RK. Putrescine and carnauba wax pretreatments alleviate chilling injury, enhance shelf life and preserve pomegranate fruits quality during cold storage. Scientia Horticulturae. 2011; 130:795-800.
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Chien PJ, Sheu F, Lin HR. Coating citrus (Murcott tangor) fruits with low molecular weight chitosan increases postharvest quality and shelf life. Food Chemistry. 2007; 100:1160-1164.
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Conforti FD, Zinck JB. Hydrocolloid-lipid coating affect on weight loss, pectin content, and textural quality of green bell peppers. Food and Chemical Toxicology. 2002; 67:1360-1363.
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Cordenunsi BR, Genovese MI, Nascimento JO, Aymoto HNM, dos Santos RJ, Lajolo FM et al. Effects of temperature on the chemical composition and antioxidant activity of three strawberry cultivars. Food Chemistry. 2005; 45:4589-4594.
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Duan J, Zhao Y, Strik BC, Wu R. Effect of edible coatings on the quality of fresh blueberries (Duke and Elliott) under commercial storage conditions. Postharvest Biology and Technology. 2011; 59:71-79.
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El-Anany AM, Hassan GFA, Ali FMR. Effect of edible coatings on the shelf life and quality of ‘Anna’ apple (Malus domestica Borkh.) during cold storage. Journal of Food Science and Technology. 2009; 7:5-11.
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Ergun M, Sargent SA, Fox AJ, Crane JH, Huber DJ. Ripening and quality responses of mamey sapote fruits to postharvest wax and 1methylcyclopropene treatments. Postharvest Biol. Technology. 2005; 36:127-134.
10. Eum HL, Hwang DK, Linke M, Lee SK. Influence of edible coating on quality of plum (Prunus salicina Lindl. cv. ‘Sapphire’). European Food Research and Technology. 2009; 29:427-434. 11. Fan Y, Xu Y, Wang D, Zhang L, Sun J, Sun L et al. Effect of alginate coating combined with yeast antagonist on strawberry (Fragaria × ananassa) preservation quality. Postharvest Biology and Technology. 2009; 53:84-90. 12. Ferreyra RM, Vina SZ, Mugridge A, Chaves AR. Growth and ripening season effects on antioxidant capacity of strawberry cultivar Selva. Scientia Horticulturae. 2007; 112:27-32. 13. Goncalves FP, Martins MC, Silva GJ, Lourenc SA, Amorim L. Postharvest control of brown rot and Rhizopus rot in plums and nectarines using carnauba wax. Postharvest Biology and Technology. 2010; 58:211-217. 14. Han C, Zhao Y, Leonard SW, Traber MG. Edible coatings to improve storability and enhance nutritional value of fresh and frozen strawberries (Fragaria × ananassa) and raspberries (Rubusideaus). Postharvest Biology and Technology. 2004; 33:67-78. 15. Han C, Zhao Y, Leonard SW, Traber MG. Edible coatings to improve storability and enhance nutritional value of fresh and frozen strawberries (Fragaria × ananassa) and raspberries (Rubusideaus). Postharvest Biology and Technology. 2004; 33:67-78. 16. Hodges DM, Forney CF. The effects of ethylene, depressed oxygen, and elevated carbon dioxide on antioxidant profiles of senescing spinach leaves. Journal of Experimental Botany. 2000; 51:645-655. 17. Jimenez A, Creissen G, Kular B, Firmin J, Robinson S, Verhoeyen M et al. Changes in oxidative processes and components of the antioxidant system during tomato fruits ripening. Planta. 2002; 214:751-758. 18. Khin MM, Zhou W, Yeo SY. Mass transfer in the osmotic dehydration of coated apple cubes by using maltodextrin as the coating material and their textural properties. Journal of Food Engineering. 2007; 81:514522.
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19. Larrigaudière C, Pintó E, Lentheric I, Vendrell M. Involvement of oxidative processes in the development of core browning in controlledatmosphere stored pears. The Journal of Horticultural Science and Biotechnology. 2001; 76:157-162. 20. Lohani S, Trivedi PK, Nath P. Changes in activities of cell wall hydrolases during ethylene-induced ripening in banana: Effect of 1MCP, ABA and IAA. Postharvest Biology and Technology. 2004; 31:119-126. 21. Malmiri J, Osman A, Tan CP. Development of an edible coating based on chitosan-glycerol to delay ‘Berangan’ banana (Musa sapientum cv. Berangan) ripening process. International Food Research Journal, 2011; 18:989-997. 22. Meng X, Li B, Liu J, Tian S. Physiological responses and quality attributes of table grape fruits to chitosan preharvest spray and postharvest coating during storage. Food Chemistry. 2008; 106:501-508. 23. Navarro-Tarazaga ML, Massa A, Perez-Gago MB. Effect of beeswax content on hydroxypropyl methylcellulose-based edible film properties and postharvest quality of coated plums (cv. Angeleno). LWT - Food Science and Technology. 2011; 44:2328-2334. 24. Perez-Gago MB, Rojas C, Del Rio MA. Effect of hydroxypropyl methylcellulose-lipid edible composite coatings on plum (cv. Autumn Giant) quality during storage. Journal of Food Science. 2003; 68:87983. 25. Purvis AC. Interaction of waxes and temperature in retarding moisture loss from and chilling injury of cucumber fruits during storage. Proceedings of the Florida State Horticultural Society. 1994; 107:257260. 26. Sánchez-González L, Pastor C, Vargas M, Chiralt A, González-Martínez C. Effect of hydroxypropylmethylcellulose and chitosan coatings with and without bergamot essential oil on quality and safety of cold-stored grapes. Postharvest Biology and Technology. 2011; 60:57-63. 27. Shao HB, Liang ZS, Shao MA, Wang BC. Changes of anti-oxidative enzymes and membrane peroxidation for soil water deficits among 10 wheat genotypes at seedling stage. Colloids and Surfaces B: Biointerfaces. 2005; 42:107-113. 28. Singh D, Mondal G, Sharma RR. Effect of Individual Shrink Wrapping on Spoilage and Quality of Peaches during Storage. Journal of Agricultural Engineering. 2009; 46(2):22-25. Page | 29
29. Singh D, Sharma RR, Samuel DVK, Pal RK. Enhancing the bio-efficacy of Debaryomyces hansenii with sodium salts for reducing the blue mould rot in apples. Indian Phytopathology. 2009; 62(4):478-483. 30. Valero D, Mula-diaz HM, Zapata PJ. Effect of alginate edible coating on preserving fruits quality in four plum cultivars during postharvest storage. Postharvest Biology and Technology. 2013; 77:1-6. 31. Valero D, Valverde JM, Martínez-Romero D, Guillén F, Castillo A, Serrano M. The combination of modified atmosphere packaging with eugenol or thymol to maintain quality, safety and functional properties of table grapes. Postharvest Biology and Technology. 2006; 41:317-327. 32. Vargas M, Albors A, Chiralt A, Gonzalez-Martınez C. Quality of coldstored strawberries as affected by chitosan-oleic acid edible coatings. Postharvest Biology and Technology. 2006; 41:164-171. 33. Velickova E, Winkelhausen E, Kuzmanova S, Alves BD. Impact of chitosan-beeswax edible coatings on the quality of fresh strawberries (Fragaria ananassa cv Camarosa) under commercial storage conditions. Food Science and Technology. 2013; 52:80-92. 34. Wang SW, Gao H. Effect of chitosan-based edible coating on antioxidants, antioxidant enzyme system, and postharvest fruits quality of strawberries (Fragaria x aranassa Duch). Food Science and Technology. 2013; 52:71-79. 35. Yaman O, Bayoundurlc L. Effect of an edible coating and cold storage on shelf life and quality of cherries. LWT-Food Science and Technology. 2002; 35:146-150. 36. Yang Z, Zheng Y, Cao S, Tang S, Ma S, Li N et al. Effects of storage temperature on textural properties of Chinese bayberry fruit. Journal of Texture Studies. 2007; 38:166-177. 37. Yu Y, Zhang S, Ren Y, Li H, Zhang X, Di J. Jujube preservation using chitosan film with nano-silicon dioxide. Journal of Food Engineering. 2012; 113:408-414. 38. Yurdugul S. Preservation of quinces by the combination of an edible coating material, semperfresh, ascorbic acid and cold storage. European Food Research and Technology. 2005; 220:579-586. 39. Zhou R, Mo Y, Li Y. Quality and internal characteristics of huanghua pears (Pyrus pyrifolia Nakai, cv. Huanhhua) treated with different kinds of coating during storage. Postharvest Biology and Technology. 2008; 49:171-179. Page | 30
Chapter - 3 Hermetic Storage Practices of Dolichos Bean Seeds for Control of Bruchids
Authors K Vanitha Department of Vegetable Science, College of Horticulture, Sri Konda Laxman Telangana State Horticulture University, Rajendranagar, Hyderabad, Telangana, India P Saidaiah Department of Genetics and Plant Breeding, College of Horticulture, Sri Konda Laxman Telangana State Horticulture University, Rajendranagar, Hyderabad, Telangana, India Harikishan Sudini International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Hyderabad, Telangana, India A Geetha Department of Crop Physiology, College of Agriculture, Professor Jayashankar Telangana State Agricultural University, Palem, Nagar Kurnool district, Telangana, India M Vijaya Department of Plant Pathology, College of Horticulture, Sri Konda Laxman Telangana State Horticulture University, Rajendranagar, Hyderabad, Telangana, India
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Chapter - 3 Hermetic Storage Practices of Dolichos Bean Seeds for Control of Bruchids K Vanitha, P Saidaiah, Harikishan Sudini, A Geetha and M Vijaya
Abstract Indian bean (Lablab purpures L.) is one of the most popular vegetable crops in India. Its ripe seed contains high protein. But, it suffers losses in the field as well as in the storage mainly due to bruchids. Many traditional and modern storage structures are tried for control of bruchids; none of them are perfect and cost effective. PICS bags by hypoxia and hypercarbia are very effective in control of pulse beetle (Callosobruchus theobromae) compared to other traditional storage bags. It is concluded that the triple layer PICS bag as chemical free hermetic technology is efficient and managed the bean quality as well as other parameters. Keywords: Storage practices, bruchids, dolichios bean, PICS bag Introduction Dolichos bean (Lablab purpures L.) also called as Dolichos bean or hyacinth bean belongs (Fabaceae) is a native of India and mainly cultivated as a inter crop with cereals. It is also called as Bonavist bean, Egyptian kidney bean, Egyptian bean, Hyacinth bean, Field bean, Indian bean, Indian butter bean, Papaya bean, Musical bean, Rondai dolichos bean, Poor man’s bean, Tonga bean, Sweet pulse, Wild bean creeper, Wild bean, Chikkadikai (Kannada), Mochai (Tamil), Chikkudu (Telugu), Shim (Bengali), Ballar (Hindi). In South India this crop is best grown for fresh green pods used as vegetable and dry seeds for preparations of various dishes and the other plant parts as fodder for livestock. The green pods contain vitamin A (864 IU), vitamin C (12.6 mg), protein (31.58%), iron (8.89 mg) and rich in calcium (78 mg). The dried seeds contain protein (40%), carbohydrates (20.04%) and fat (1%). Dolichos bean major producing states are Uttar Pradesh, Telangana, Madhya Pradesh, West Bengal, Andhra Pradesh, Karnataka, Tamil Nadu, Maharashtra, Haryana and Kerala. Legumes are rather unique compared to Page | 33
other vegetables in that they can obtain free atmospheric nitrogen through their symbiotic association with the nitrogen fixing bacteria. The nitrogen fixed in the root nodules are not only available to the plant but they also enrich the soil, in varying amounts, when the plants complete their life cycle. Indian bean is one of the most popular perennial vegetable crops in India. The nutritive quality of dolichos bean is better than that of French bean (Aykroyd, 1963). The ripe seed contains high protein (Schaaffhausen, 1963). However, the crop suffers losses in the field as well as in the storage. Callosobruchus Spp. Callosobruchus is a genus of beetles in the family Chrysomelidae, the leaf beetles. It is in the subfamily Bruchinae, the bean weevils (Tuda et al., 2006). Many beetles in the genus are well known as economically important pests that infest stored foodstuffs (Tuda et al., 2005). These beetles specialize on legumes of the tribe Phaseoleae, which includes many types of beans used for food. Host plants include mung bean (Vigna radiata), adzuki bean (V. angularis), rice bean (V. umbellata), cowpea (Vigna unguiculata), Bambara groundnut (V. subterranea), pigeon pea (Cajanus cajan), lablab (Lablab purpureus), and common bean (Phaseolus vulgaris) (Tuda et al., 2005). They can also be found in peas, lentils, chickpeas, and peanuts (Tuda et al., 2005). Bruchid (Callosobruchus theobromae) Bruchids also called as pulse beetle are distributed throughout the world except Antartica and the largest number of species occurs in tropical regions of Asia, Africa and South America (South, 1979). There are approximately 1300 described species of bruchids in the world and as many again to be described (Johnson and Kistler, 1987). About 84% of the known hosts of bruchids are in the family Leguminosae (Johnson, 1970) and 33 families have been reported as hosts (Kinslover, 1979). Callosobruchus theobromae (Linnaeus) infests developing pods and seeds of Dolichos lab lab syn. Lablab purpureus sweet throughout the year and extended its host range on other legume commodities in the stores. Perusal of literature revealed C. theobromae to be a pest of D. lab lab but the present investigations have unveiled its biology and pest status for the first time on other edible legume's viz. Glycine max, P. aureus and V. sinensis. In India, 117 bruchid species belonging to 11 genera are been reported by (Arora 1997). It includes Acantoscelides, Bruchids, Caryodon, Callosobruchus, Zabrotes and Sulkobruchus. Of these, genera Page | 34
Callosobruchus is prominent in its incidence and includes species like C. chinensis (L.), C. maculatus (F.), C. analis (L.), C. theobromae (L.) and C. phaseoli (Gyll.) which cause heavy losses to the stored grains. Stored product pest beetles retain a higher percentage of water in their body, relative to the water content of their diet, than beetles that feed on fresh crops. Majority of the pulses are susceptible to pulse beetles mainly because of lack of proper management practices and unavailability of resistant varieties to bruchids. In general, it is prone to damage by insect pests and microorganisms compared to many cereals. Among insect pests, bruchids assume greater importance as they damage the final produce in the field and storage which cause losses quantitatively and qualitatively. Life Cycle: Development and Larval Morphology of (Callosobruchus theobromae) (L.) (Bruchidae: Coleoptera) These bruchids are known to lay eggs on pods of different pulses and larvae through the chorion of eggs directly through the pod wall, seed coat and then into the seed where the larvae develop and pupate to emerge finally as adults from the pod itself. Bruchids are mainly stored pests but the infestation starts in field before harvest. The bruchid, Callosobruchus theobromae L. was recorded on redgram from Karnataka (Usman and Puttarudraiah, 1955; Prabhakara, 1979) from Orissa (Hariprasad Patnaik, 1984) on soybean from Punjab (Arora, 1977). The life cycle of Callosobruchus theobromae (L.), a pest of the legume Dolichos lablab (L.), was observed. Its incubation period was 6.7±0.67 days under controlled laboratory conditions. First-instar larvae hatched out from the ventral surface of eggs and bored into the wall of the pod or testa of the seed to reach the seed contents. The entrance hole on the seed was small and plugged due to accumulation of larval frass. Freshly emerged first-instar larva was minute and measured 0.566 ± 0.04 mm in length and 0.304 ± 0.04 mm in width. Larvae had a well-developed, dark brown, prothoracic retracted prognathous head provided with usual mouthparts, including dark brown, highly sclerotized, equal-sized mandibles and an H-shaped plate on the prothorax. Larval and pupal development was completed inside the host seed. Last-instar larva was comma-shaped, measuring 3.712 ± 0.36 mm in length and 1.884 ± 0.14 mm in width. Pupa took 6.1 ± 0.73 days to transform into an imago and the adult insect cut a circular window to emerge. The life cycle was completed in 31.4 ± 2.11 days at 30-35 0C and 86-98% humidity. After passing the winter hibernated larvae, adults emerged during March Page | 35
and April. Amorous males impregnated the females among the seed and pods of the host plant. Egg laid on seeds and pods developed into first instar larvae, which penetrated the seeds of host plant. Remaining life cycle was completed inside the host seed, and adults came out by cutting a circular window in the testa of host seed. Six to seven overlapping generations have been recorded between April to October. The life cycle is completed in 28.9 ± 1.72 days. Respiratory Biology of Bruchids: The respiratory biology of Callosobruchus theobromae revealed that pulse beetle required about 39.96 ml of oxygen and 26.20 ml of carbon dioxide simultaneously for its development from egg to pupal stage. The respiratory quotient (RQ) at different life stages showed highest RQ for development from first instar to final instar. Creating hypercarbia and hypoxia condition will lead to death of bruchid. The respiratory quotient conditions in the triple layer PICS bag storage were less than RQ at all stages with less than essential oxygen levels required for bruchid survival. Storage Practices In general, post harvest losses due to bruchid damage are high in dolichos bean. The bruchid or infested pulses are rendered unfit for consumption because of the presence of excreta and metabolic waste products like uric acid which leads to fungal infection of the grains (Gowda and Kaul, 1982). If proper care was not taken, damage due to bruchids accounts up to 100%. Farmers use a variety of commercial and traditional methods to control bruchids, many of which have restricted value because of cost, labour and potential toxicity. For instance, insecticides, they often misuse them resulting in health and environmental problems. Ash is also used for storage, but only for small quantities due to labour requirement and because many people consider ash as dirty and refuse to eat food stored in ash. Other storage methods include metal drums, widely available and used in northern Senegal and South Benin. In recent years, there has been a decline in metal drum use due primarily to their cost and the inflexibility of drum storage to production quantities. In addition, many farmers were using insecticides to store in metal drums because many were rusting (hence, no longer air tight). Some farmers employ indigenous methods such as sieving and solarisation, mixing with fine dusts (wood ashes, sand, lime and animal dung), or admixing with botanical products that exert some fumigant activity, contact toxicity or repellency and oviposition deterring properties. The efficacies of these native
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methods are however, low because there exist no standard (dosage and timing) application guidelines and their use is only practical where the desire is to preserve small quantities for seed or home consumption, and not large quantities for sale. Some storage methods also interfere with quality (Songa and Rono, 1998). Therefore, an increased attention towards non-chemical methods of stored product protection is the need of modern agriculture system, because chemical controls often not affordable for sustainable farming, where as chemicals available are health hazards. The majority of smallholder farmers use traditional methods to handle and store their grain after harvest. Storage of the grain in woven bags is inexpensive but requires the application of insecticide (De Groote et al., 2013; Kamanula et al., 2010; Maina et al., 2016). Farmers have become more aware of the potential health issues associated with these insecticides, especially when the grain is stored within the home. Over the past decade, the application of hermetic storage bags has been promoted in the Sub-Sahara region for the storage of maize and other vulnerable crops (Baoua et al., 2014; De Groote et al., 2013). Traditional Grain Storage Practices Farmers and traditional grain processors have been evolving number of traditional practices through trial and error method, to avoid huge loss that are occurring in stored pulse grains due to insect and pest infestation. Certain practices are unique to a given culture of a society and vary between countries, regions, villages and even communities. Indigenous practices emanate from the cultural contact of the people concerned and evolve in close contact with specific environmental conditions and are based on traditional society’s intimate knowledge of their environment. Storage Structures Storage in Bags: This method consists of conserving dried and cleaned grain in bags made of plant fiber or plastic, and neatly stacking the bags in carefully prepared areas. It is economical and well-adapted to local grain transport and marketing conditions. Traditional Storage Bins: Farm families use various grain bins of local design, made from locally available materials, such as bamboo, clay, mud, straw, jute bags, bricks, and wood. Those made of unburnt or burnt clay, stone slabs, or bricks used to store grains and legumes. These bins restrict airflow but are ineffective against rodents and moisture. Those made of bamboo, wood, straw, or other dried plant material, used Page | 37
for storage of paddy and maize. These bins allow free flow of air for drying but are open to insects, rodents, fire, domestic animals, rain, and subsoil water. Stone slab, brick, and burnt clay bins can be made moisture-proof by placing polythene sheets between two layers of brick or slab and by building the bin on a raised platform. Such structures are safe for effective fumigation. Storage in Flexible Silos: A flexible silo is made on a concrete platform, generally circular in shape. Walls of galvanized screening about 2.5 meters high are erected around it and the inner walls lined with a thick film of plastic. On the outside, about 50 cm from the walls, galvanized metal sheets about 1 m high surround the silo to protect the grain from rodent attacks. Flexible silos of 500 tonnes are the most common, but some are also built with storage capacities of 250-1000 tonnes. Warehouses and Storehouses Silos: To store grains, warehouses are used to stack the bags. Periodical checking of the stored lots is done for timely spray of insecticides for any visible insect activity. At rural levels, even huts are used to serve the purpose. A warehouse must prevent the grains from getting wet, protect the grains from high temperatures, prevent the access of transport the bags. Bulk Storage: This method consists of storing unpackaged grain in structures built for this purpose (bins, silos). There can be relatively simple low capacity structures for storage of agricultural surpluses in production areas, or large complex installations for commercial or industrial storage of products. In developing countries like India, high initial investment and lack of bulk material handling systems prevent wider adoption of this technology. Metal Bins-Indoor Design: Bins for community use and for urban households. Larger bins can be used by several households or whole communities. Smaller bins made of metal or plastic are suitable for households in urban areas. They can be bought from commercial manufacturers or made locally. Low Capacity Silos For Farm Storage: On-farm storage for home consumption is the basic form of rural storage in India. Metallic bins low capacity, metal drums are best adapted to rural storage. The security of metal bins against rodent and features of air-tightness make the bins more versatile. High Capacity Silos: It can also be used to fumigate the bin whenever any insect activity is observed. In addition to that, in airtight silos oxygen Page | 38
level depletes due to respiration of grains or living insects and microorganisms, this is called controlled atmospheric storage, making internal atmosphere difficult for survival of insects. Airtight silos still have limited distribution because of technological complexity especially for the high capacity bins. Synthetic Silos: Various attempts have been made to develop small scale storage bins, using synthetic materials such as butyl rubber and high density polyethylene. However, such bins proved to be either too expensive or prone to damage by pests. Also the management level required by such storage facilities is probably too high for most rural situations. Aerial Storage: Maize cobs, sorghum or millet panicles are sometimes tied in bundles, which are then suspended from tree branches, posts, or tight lines, on or inside the house. This precarious method of storage is not suitable for very small or very large quantities and does not provide protection against the weather (if outside), insects, rodents, or thieves. Open Timber Platforms: A platform consists essentially of a number of relatively straight poles laid horizontally on a series of upright posts. Platforms in the open may be raised at least 1 metre above ground level. Grain is stored on platforms in heaps, in woven baskets or in bags. Storage Baskets (Cribs) Made Exclusively of Plant Materials: Traditional granaries (cribs) are usually constructed entirely out of locally available plant materials: timber, reeds, bamboo, etc. Under prevailing climatic conditions most plant material rot fairly quickly, and most cribs have to be replaced every two or three years. Calabashes, Gourds, and Earthenware Pots: These small capacity containers are most commonly used for storing seed and pulse grains, such as cowpeas. Having a small opening, they can be made hermetic, by sealing the walls inside and out with liquid clay and closing the mouth with stiff clay, cow dung. Jars: These are large clay receptacles whose shape and capacity vary from place to place and serve equally for storing seeds and legumes. So that they may remain in good servicable condition, they should not be exposed to the sun and should not be either porous or cracked. Underground Storage: Practiced in India for long term storage, pits vary in capacity (from a few hundred kilogrammes to 200 tonnes). The entrance to the pit may be closed either by heaping earth or sand onto a timber cover, or by a stone sealed with mud. Page | 39
Other Traditional Storage Practices
Red gram storage with common salt
Ash seed treatment in sorghum
Ragi storage with neem and thumbai leaves
Storage of grains using camphor
Storage of seeds with lime
Neem oil in seed storage
Need seed kernel extract dip jute gunny bags
Storage of vegetable seeds with cow dung
Pungam leaves in paddy storage
Neem leaves against storage pests Pulse grains storage with ash
Paddy husk in managing storage pests
Mud pots in grain storage
Storage of tamarind with salt
Storage of grains with sweet flag
Oil storage practices
Improved Grain Storage Practice (Pics Technology) Triple layer bags were developed by Professor Larry Murdock in 1987 at Purdue University, in association with Cowpea CRSP (Cowpea Collaborative Research Support Program) and USAID team of researchers to combat bruchid infestation on cowpea in Cameroon. Working Principle of PICS Bag: The triple layer PICS bag by hermetic principle creates an airtight condition and which causes hypercarbia (increased levels of carbon dioxide) and hypoxia (decreased levels of oxygen) due to the respiration of biotic organisms present in the bag which cause death of pest at that conditions and protects the produce stored in the bag. Purdue Improved Crop Storage (PICS) bag is a simple and effective technology for reducing grain losses to insects during post harvest storage. The technology was initially developed for cowpea storage in West Africa but is currently being used to store many different cereal and legume crops including maize, beans, sorghum, mung bean, pigeon pea, wheat and rice. Its use has spread to many countries in Sub-Saharan Africa and Asia. Since 2007, PICS bags have been disseminated on a large scale. While substantial, Page | 40
the 3.5 million PICS bags represent only 1600 tons of plastic material (Ogunniyi, 1990). In West Africa, cowpea (Vigna unguiculata) productionwas estimated to be 4.5 million tons. This essential food legume for rural populations is ravaged by insects in the field and during storage after harvest. Losses caused by bruchids are estimated to range from 25 to 95% after 3 to 4 months of storage (Singh et al., 1985). Over the last ten years, post-harvest protection of cowpea grain in the Sahelian zone of Africa has improved considerably thanks to the introduction and dissemination of the hermetic triple-bagging technology called PICS (Purdue Improved Crop Storage) (Baributsa et al., 2010). A PICS bag consists of a woven polypropylene outer bag and two internal polyethylene liners. The bags are effective in preserving grain quality for at least fourteen different crops. The technology has been directly demonstrated to more than 5 million farmers in 56,000 villages in Africa and at least 10 million bags have been sold by June 2017. The bags are made of plastic with low permeability to atmospheric gases. Although these bags cost significantly more than the traditional woven bags, the need for insecticide applications is eliminated. One of the concerns associated with storing maize in hermetic bags has been the efficacy for controlling the growth of mycotoxigenic Aspergillus sps. and the potential for aflatoxin accumulation during storage. Aflatoxins are potent carcinogens produced primarily by A. flavus and A. parasiticus (Woloshuk and Shim, 2013). The triple layer Purdue Improved Crop Storage (PICS) bags consists of three layers; inner and middle layers were made up of 80µ thickness high density polyethylene (HDPE) material and do not allow diffusion of gases (Oxygen and Carbon dioxide) while the outermost layer is a normal woven sac made up of polypropylene and provides strength for handle. (Baributsa et al, 2012), they provide excellent protection of cowpea grain against bruchid seed beetles in West Africa (Murdock et al., 2012: Baoua et al., 2012, 2013). Steps for Using of PICS Bag The triple layer PICS technology owes its effectiveness to the airtight storage.
Threshed grain is put into 50 to 100 kg capacity high density polyethylene (HDPE) bags taking care to fill the bag completely without air pockets, except for a neck of 20 to 30 cm length.
This first bag is tied securely shut at the neck and then surrounded by a second bag of the same material and thickness. Page | 41
The middle layer bag, completely surrounding the first, is tied shut at the mouth in the same way as the first.
These two sealed bags are then placed inside a third plastic bag, which is woven nylon or polypropylene for strength.
This container thus formed can be handled without bursting the inner bags, and is readily accepted by grain handlers.
The combination of two liners and one woven bag provide a robust composite that can continue to function after handling and minor damage. Triple layer PICS bags can be used to store grain for multiple seasons. Farmers can use triple layer PICS bags for atleast three years to store produce (Baributsa et al., 2014: Moussa et al., 2014). Triple layer PICS bags that have been used for several years have been shown to be as effective as new triple layer PICS bags (Baoua et al., 2012). When triple layer PICS bags lose their air tightness, farmers use them to store crops that are less susceptible to pests (Baributsa et al., 2014). Effectiveness of PICS Bag Purdue Improved Crop Storage (PICS) bags provide excellent protection of cowpea grain against bruchid seed beetles in West Africa (Murdock et al., 2012; Baoua et al., 2012, 2013). They are likewise effective in protecting other stored grains against insect pests, including (1) maize attacked by the larger grain borer (Njoroge et al., 2014); (2) Bambara ground nut against bruchids (Baoua et al., 2014b), and; (3) mung beans and pigeonpea (Baoua et al., 2014b; Mutungi et al., 2014) attacked by bruchids. PICS bags, on the other hand, were found not to be effective in controlling cassava chips (Hell et al., 2014) infested with larger gain borer. We sought to determine if PICS bag could protect H. sabdariffa grain against its main storage pest while maintaining seed viability. Williams et al. (2014) demonstrated the use of PICS bags for the storage of maize at 27 0C in laboratory conditions, showing that PICS bags mitigate the growth of A. flavus and the accumulation of aflatoxin during storage as well as maintaining the initial moisture content of the maize. Similar results were reported for the storage of shelled peanuts in hermetic bags at 30 0C (Navarro et al., 2012). However, (Fusseini et al., 2016) found an increase in maize moisture content as well as aflatoxin levels during storage in triplelayer hermetic bags across multiple temperatures under laboratory conditions. Their results also indicated that cooler temperature (16 0C) resulted in the largest increase in aflatoxin accumulation. This conflicting evidence furthers the debate on the efficacy of hermetic storage for the Page | 42
mitigation of accumulation of aflatoxin. Under field conditions in Brazil and Kenya, the number of Aspergillus spp. increased during storage, even in hermetic storage systems (Di Domenico et al., 2016; Maina et al., 2016; Viebrantz et al., 2016). The Purdue Improved Crop Storage (PICS) hermetics bags were compared with polypropylene woven bags. PICS bags are a triple layer hermetic storage bag that are effective at protecting stored grains from damaging insect infestation (Baoua et al., 2014; Murdock et al., 2012). Results demonstrated the efficacy of PICS bags for protecting the grain from moisture and temperature fluctuations during storage. The performance of PICS bags in maintaining grain quality under the extreme environmental conditions obtained in the Sahelian zone of Africa. PICS bags stored outside with daily direct exposure to the sun for 10 or 11 h can still preserve cowpea grain for up to 4.5 months in a Sahelian environment under average daily temperatures ranging from 11.4 to 44.6 0C. Despite the extreme conditions, the PICS bags still maintain airtight conditions that cause high mortality and arrest population growth of C. maculatus. PICS bag exposed to the sun were as effective as those stored inside the laboratory. Our present results confirm the findings of previous studies showing that PICS bags preserve cowpea grain extremely well (Baoua et al., 2012, 2015; Murdock and Baoua, 2014) when they are stored inside buildings. Substantial protection for some months even occurs when the bags are exposed to sun and weather. Average daily temperatures in PICS bags held outside or inside the laboratory remained highly correlated and dependent on the prevailing ambient temperature. Williams et al. (2017) reported similar results after testing PICS technology for maize storage in the USA. As regards relative humidity, there was no significant correlation between RH values recorded within in PICS bags and outer RH when they were stored inside or outside the laboratory. Despite high daytime and low nighttime temperatures, PICS bags buffer cowpea grain from variations of ambient humidity, which is in agreement with results reported by Baoua et al. (2014) with maize stored in PICS bags. Relative humidity in PICS bags stored inside and outside the laboratory remained relatively constant with variations of less than 10% for the 4.5 months of storage. During this same period ambient RH varied more than 30%. PICS bags stored outside had relatively higher internal RH compared to bags stored inside the laboratory and the gap increased with time. The effect of continued exposure to the sunlight and varying internal temperatures combined with slow deterioration of the bags over time probably account for the higher RH in PICS bags stored outside. Page | 43
Degradation of the polypropylene outer woven bag was likely due to the effect of sunlight and high temperatures on the organic chemical compounds that make up the plastic bags material. Radiant energy leads to a reorganization of the polymer chains which affects the flexibility and structure of the plastic (Tocchetto et al., 2001). The bags stored inside are reused by farmers for 3 storage seasons on average (Baributsa et al., 2014; Baoua et al., 2013). Exposure of PICS bags to the sun affected the cowpea grain stored outside by decreasing germination by 7.6% compared to the germination rate at the outset of storage. This modest reduction in germination probably result from the swings in relative humidity resulting from the condensation and evaporation as well as the large variations in daily temperatures. Germination of grain held in woven bags was severely affected, most of it primarily because of damage to the grain caused by insects developing in these bags. There was a still greater drop in germination of grain stored in woven bags outside – a decrease of 60% compared to the initial germination and at least 5 times less than that seen in grain in woven bags stored inside. Increases in temperature in woven bags stored outside due to the extremely high exterior temperatures as well as to bruchid activity resulted in an increase in the proportion of grains with holes (73.2% inside to 88.5% outside) and seed weight losses (16.6% - 29.2%). Damage to grain measured as emergence holes and grain weight loss appeared to be slightly higher in woven bags stored outside than those kept inside. Higher temperatures in bags exposed to sunlight may have contributed to greater insect feeding and reproductive activity and hence increasing damage to cowpea grains stored outside. We noted that variations in temperatures and RH resulted in seed cracking and contamination by other microorganisms, etc. This study gave us new information on the performance of PICS bag when exposed to extreme environmental conditions of the Sahel. Despite the harsh conditions, PICS bags stored outside can maintain grain quality and good germination rates for several months. Clearly it is strongly preferable to store PICS bags inside, where they are exposed to milder ambient conditions and are not exposed to sunlight. But in harvest situations and in the difficult world of international development or aid emergencies where large shipments of grain may occur and arrive in localities where there is limited storage space, PICS bags could be held outside for a limited time, if shielded from livestock and thieves, and be safely used to store grain and prevent losses to bruchids. Once interior storage space became available, they could be moved inside to more favorable conditions. Exposure to the sun should be avoided if at all possible. The performance of the PICS bags for a few months outside is Page | 44
minimally affected by exposure to the sun, but the longevity and reuse of the bags are reduced. In an experiment the numbers of adults and emergence holes in Hibiscus grain held in PICS bags for six months were far less than observed in the woven control bag. After six months of storage the Spermophagus sp. population was 91.2 adults per 500 g of grain held in woven bags, while in PICS bags the pest density was less than 2 living insects per 500 g. This finding is consistent with that obtained by Mutungi et al. (2014) who tested PICS bag for storing mung beans and pigeon peas. After six months of storage in woven bags the mean H. sabdariffa grain weight losses was 8.6%. It is interesting that this is substantially lower than the weight loss observed by Baoua et al. (2014a) when bruchid-infested Bambara ground nut was stored in woven bags. Regarding the near absence of abrasions and holes in the HDPE liners, it appears that Spermophagus sp. is less damaging to HDPE compared to Callosobruchus maculatus on cowpea (Baoua et al., 2012) and larger grain borer (P. truncatus Horn) on maize (Baoua et al., 2014b). Oxygen and Carbon Dioxide Levels in The PICS Bag: Triple layer PICS bags work as do other hermetic storage contains such as sealed steel drums (Seck et al. 1996) because insects respire aerobically and thus utilize the oxygen in the airtight container while also raising CO2 levels. Once the oxygen level in the container falls sufficiently low, insects cease feeding and become inactive (Margam, 2009). Inactivity itself causes the growth and development to cease and in turn reproduction stops. This results in the arrest of pest population growth. During the oxygen deficit caused inactivity insects begin dying. The early instar larvae and pupae appear to be particularly vulnerable. Respiration by the grain, insects, and fungi lead to a reduction in oxygen and an increase in carbon dioxide within the hermetic bag (Murdock et al., 2012). Within a short period of time, conditions become inhibitory to insect and fungal growth and development. The O2 level in PICS bags dropped over the first three weeks while CO2 rose. By contrast, there was little change in the levels of these two gases in the woven control bags. This is simply explained by the fact that the triple layer PICS bags are practically hermetic and greatly retard gas movement across the bag walls. Woven bags, on the other hand, have a single porous wall, and as insects living in the grain held in these bags grow, develop and reproduce, the O2 they consume is replaced by diffusion from the environment and the CO2 they produce likewise diffuses out, resulting in little change in the concentrations of the two gases within the woven bags. The drop in O2 and rise in CO2 observed in Page | 45
PICS bags leads to Spermophagus sp. mortality and failure of its population to grow. Our results point towards cessation of egg production and development, as well as larval and adult mortality. Similar changes in gas composition and arrest of population development have been observed with stored maize (De Groote et al., 2013) and Bambara ground nuts (Baoua et al., 2014a) as well as with other stored crops and pests. The simplest hypothesis to explain these results is that prolonged restriction in available O2 not only suppresses the insect population growth but leads to the reduction in the supply of water because of the inadequate supply of O2, leading to eventual insect death by desiccation (Murdock et al., 2012). PICS bags become even more economical if they can be reused (Jones et al., 2011). Bag reuse depends on the degree of damage seen as holes, abrasions, broken seals and tears. When no holes, abrasions or more serious damage is seen, the bag will continue to protect grain for additional uses. PICS bags used for cowpea in Niger are used, on average, for three storage seasons (Baributsa et al., 2014). Exposure of the grain to lowered levels of oxygen in PICS bags evidently had no effect on seed viability, just as has been observed in the case of cowpea (Baoua et al., 2013); mung bean (Mutungi et al., 2014); Bambara ground nut (Baoua et al., 2014a); and maize (Baoua et al., 2014b). The results of other studies focused on PICS bags, which demonstrated better outcomes for grain stored in the triple bags than for grain stored in other ways (Murdock et al., 2012, Baoua et al., 2012) (16±21). PICS triple bags possess several properties that allow them to maintain grain quality. First, the plastic liners greatly hinder transmission of oxygen into and out of the grain bulk. When oxygen levels fall rapidly in the infested PICS bag group, this creates a negative feedback loop on the insect population that was driving this decline. Consumption of oxygen by the insects led to conditions that were unfavorable for further population growth. Once oxygen levels fell to around 5%, oxygen, consumption noticeably slowed down and feeding activity ceased. Even after the bags were opened and resealed during the bimonthly sample collection, the surviving insects drove the oxygen below sustainable levels again. Murdock et al., 2014 have pointed out that the PICS bags' ability to create low-oxygen environments is the key to their protective nature. Contributing to this protection is the higher level of oxygen within the space between the two polyethylene liners. While a plastic membrane like the polyethylene liners can permit minimal diffusion of oxygen, this process is slow and dependent on the difference in concentrations of oxygen on either side of the membrane. Our current results show for the first time Page | 46
that oxygen levels in the inter-liner space can be 3±4% higher than the inner grain environment. Thus, as originally suggested (Martin et al., 2015) this space of higher oxygen creates a buffer zone that discourages oxygen movement across both liners, as it reduces the difference in oxygen concentration on either side. The result is slower movement of the oxygen into the grain environment from the ambient air than if there were a single layer, even if that layer were thicker than typical for PICS bags. This fact establishes the value of the double-layer of HDPE as part of the triple bag configuration. Preventing water vapor transmission is another valuable trait of triple layer bags. PICS bags had higher internal R.H. and maintained grain moisture better than woven bags, in which the grain dried out as ambient R.H. dropped over the 8 month storage period. This is consistent with previous observations showing the PICS bags have a more stable R.H. environment than other bag types (Njoroge et al., 2014, Vales et al., 2014). A stable moisture environment is beneficial from a farmer's perspective, as it creates an expectation that initial grain moisture conditions will remain the same so long as the bag is closed. For tropical regions, having a barrier against water vapor transmission would prevent stored maize from absorbing water when humidity is high (Devereau et al., 2002) and from losing water when it is low. Overall, the oxygen and moisture conditions within PICS triple-layer bags appear to maintain the quality of stored maize. Both PICS bag treatments had similar germination rates to the non-infested woven bag treatment group and higher rates than the infested woven group. This agrees with previous observations for maize stored in PICS bags at similar moisture ranges (Williams et al., 2014). Storage of Dolichos Bean Seed: The triple layer PICS bags hermetic technology is efficient in managing moisture content (%), germination per cent, test weight compared to other bags over periods of storage. They are also highly useful for retaining carbohydrate (%) and protein (%) at almost same levels compared to initial values The use of triple layer PICS bag as improved storage practice by creating hypercarbia and hypoxia and maintaining same temperature highly useful in controlling pulse beetle over six months of storage period. The chemical free triple layer PICS bag technology can be efficiently used for long term storage of produce and the bags can be used for multiple times over seasons. Conclusions: Giving the interest in the technology and its potential to reach tens of millions of farmers across the globe, it is both desirable and necessary to promote proper use and encourage recycling or re-purposing of triple layer PICS bags. Proper management and use of triple layer PICS bags Page | 47
can benefit farmers by extending their life span, thus increase farmer’s incomes and reduce the impact of the triple layer PICS bags on the environment. To increase the longevity of triple layer PICS bags for grain storage, users should: Store clean grain containing no debris, which tends to make holes in the bags. Handle the bags carefully to avoid damaging them, especially when tying and transporting them. Store bags in clean areas to avoid damage by rodents and other household objects. Store bags away from direct sunlight and extreme heat. Patch small holes or tears with tape to maintain air-tightness. Triple layer PICS bags should be recycled for other use when the liners have accumulated numerous holes or tears that cannot be repaired with tape. The lifespan of triple layer PICS bag can be increased by farmers good practices. Because triple layer PICS bags are not treated with insecticides and pose no hazard, filled bags are usually stored in the living or sleeping rooms on low resource farms. Most smallholder farmers treat triple layer PICS bags as granaries, that is, they do not sell the triple layer PICS bags with the grain. Usually, farmers empty the grain into a different container before taking it to the market. The triple layer PICS bag is folded and kept to use again in the following storage season. Based on the results obtained from the study on use of different storage bags on management of dolichos bean seed moisture content, germination per cent, test weight (g), quality (protein content, carbohydrate content and fat content) and pulse beetle (Callosobruchus theobromae) the following conclusions were drawn
The triple layer PICS bag is not influenced by the surronding environmental conditions and maintains the moisture content of the produce stored in the bag and no further loss of moisture to the seed.
The triple layer PICS bag created the hypercarbia (increased levels of carbon dioxide) and hypoxia (decreased levels of oxygen) conditions within the bag and lead to mortality of pest. Which further reduced the damage to seed. This helped in maintaining the good germination per cent, test weight, protein content and carbohydrate content with in the seeds stored in the bag.
The triple layer PICS bag resulted in complete mortality of bruchids in the bag and there was no further loss of seed that was stored for longer duration.
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Triple layer PICS bag maintained the constant temperatures within the bag irrespective of surrounding environment.
The bruchid required certain amount of oxygen for its growth, development and completion of its life cycle. From the results the RQ of 0.53 was registered. Hence, maintaining RQ in the storage exist below 0.53 will keep the produce free from infestation of pulse beetle. Creation of hypercarbia (increased levels of carbon dioxide) and hypoxia (decreased levels of oxygen) conditions lead to mortality of the insect.
It is concluded that the triple layer PICS bag as chemical free hermetic technology is efficient and managed the moisture content (%), germination per cent (%), test weight (g), quality (protein content (%), carbohydrate content (%) and fat content (%) and pulse beetle (Callosobruchus theobromae) compare to other traditional storage bags.
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30. Moussa B, Abdoulaye T, Coulibaly O, Baributsa D, Lowenberg-De Boer J. Adoption of on-farm hermetic storage for cowpea in west and central Africa in. J Stored Prod. Res. 2012, 2014; 58:77e86. 31. Murdock LL, Bauoa IB. On Purdue Improved Cowpea Storage (PICS) technology: background, mode of action, future prospects. J Stored Prod. Res. 2014; 58:3-11. 32. Murdock LL, Margam V, Baoua I, Balfe S, Shade RE. Death by desiccation: Effects of hermetic storage on cowpea bruchids. J Stored Prod. Res. 2012; 49:166-170. 33. Mutungi CM, Affognon H, Njoroge AW, Baributsa D, Murdock LL. Storage of mung bean (Vigna radiata [L.] Wilczek) and pigeonpea grains (Cajanus cajan [L.] Millsp) in hermetic triple-layer bags stops losses caused by Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). J Stored Prod. Res. 2014; 27:239-e243. 34. Navarro H, Navarro S, Finkelman S. Hermetic and modified atmosphere storage of shelled peanuts to prevent free fatty acid and aflatoxin formation. In: Athanassiou CG, Kavallieratos N, Weintraub PG. (Eds.), Integrated Protection of Stored Products. IOBC-WPRS, Volos (Greece), 2012, 183-e192. 35. Njoroge AW, Affognon HD, Mutungi CM, Manono J, Lamuka PO, Murdock LL. Triple bag hermetic storage delivers a lethal punch to Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) in stored maize. J of Stored Prod Res. 2014; 58:12-19. 36. Ogunniyi DS. The plastics and rubber industries in Niger. Plastic and Rubber International. 1990; 15(1):26-27. 37. Prabhakara GS. Studies on the bruchid fauna infesting pulse crops of Karnataka with special emphasis on the bio ecology of Callosobruchus chinensis L. (Coleoptera: Bruchidae), M.Sc. (Agri) Thesis, University of Agricultural Sciences, Banglore, 1979, 168. 38. Schaaffhausen RV. Dolichos lablab or Hyacinth bean, its use for feed, food and soil improvements. Economic Botany. 1963; 17:146-153. 39. Seck D, Lognay G, Haubruge E, Marlier M, Gaspar C. Alternative protection of cowpea seeds against Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) using hermetic storage alone or in combination with Boscia senegalensis (Pers.) Lam ex Poir. J Stored Prod. Res. 1996; 32:39-44.
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40. Singh BB, Singh SR, Adjadi O. Bruchid resistance in cowpea. Crop Sci. 1985; 25(5):736e739. 41. Songa JM, Rono W. Indegenous methods for bruchid beetle (Coleoptera: Bruchidae) control in stored beans [Phaseolus vulgaris (L.)]. International Journal of Pest Management. 1998; 44:1-4. 42. South BJG. Biology of Bruchidae. Annu. Rev. ENT. 1979; 24:449-473. 43. Tocchetto RS, Benson RS, Dever M. Outdoor weathering evaluation of carbon-black-filled, biodegradable copolyester as substitute for traditionally used, carbon-black-filled, non-biodegradable, high-density polyethylene mulch films. J Polym. Environ. 2001; 9(2):57e62. 44. Tuda M. Ecological factors associated with pest status in Callosobruchus (Coleoptera: Bruchidae): high host specificity of nonpests to Cajaninae (Fabaceae). Journal of Stored Products Research. 2005; 41:31-45. 45. Tuda M. Evolutionary diversification of the bean beetle genus Callosobruchus (Coleoptera: Bruchidae): traits associated with stored‐product pest status. Molecular Ecology. 2006; 15(12):3541-51. 46. Usman S, Puttarudraiah M. A list of the insects of Mysore including the mites. Bull. Dept. Agric. Mysore. 1955; 16:103. 47. Vales MI, Rao GV, Ranga RH, Sudini H, Patil SB, Murdock LL. Effective and economic storage of pigeon pea seed in triple layer plastic bags. J of Stored Prod Res. 2014; 58:29-38. 48. Viebrantz PC, Radunz LL, Dionello RG. Mortality of insects and quality of maize grains in hermetic and non-hermetic storage. Rev. Bras. De. Eng. Agric. E Ambient. 2016; 20:487-e492. 49. Williams SB, Baributsa D, Woloshuk C. Assessing Purdue Improved Crop Storage (PICS) bags to mitigate fungal growth and aflatoxin contamination. J of Stored Prod Res. 2014; 59:190-e196. 50. Williams SB, Murdock LL, Baributsa D. Storage of maize in Purdue improved Crop storage (PICS) bags. PLoS One. 2017; 12(1):e016-8624. 51. Woloshuk CP, Shim WB. Aflatoxins, fumonisins, and trichothecenes: a convergence of knowledge. Fems Microbiol. Rev. 2013; 37:94e-109.
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Chapter - 4 Purdue Improved Crop Storage (PICS) Bags for Control of Aflatoxins in Dry Chillies
Authors K. Madhusudhan Reddy Department of Vegetable Science, College of Horticulture, Sri Konda Laxman Telangana State Horticulture University, Rajendranagar, Hyderabad, Telangana, India P. Saidaiah Department of Genetics and Plant Breeding, College of Horticulture, Sri Konda Laxman Telangana State Horticulture University, Rajendranagar, Hyderabad, Telangana, India Harikishan Sudini International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Hyderabad, Telangana, India A Geetha Department of Crop Physiology, College of Agriculture, Professor Jayashankar Telangana State Agricultural University, Palem, Nagar Kurnool, Telangana, India M Vijaya Department of Plant Pathology, College of Horticulture, Sri Konda Laxman Telangana State Horticulture University, Rajendranagar, Hyderabad, Telangana, India
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Chapter - 4 Purdue Improved Crop Storage (PICS) Bags for Control of Aflatoxins in Dry Chillies K Madhusudhan Reddy, P Saidaiah, Harikishan Sudini, A Geetha and M Vijaya
Abstract Dry chillies are commercial produce of international importance. The occurrence of moulds and mycotoxins can deteriorate the viability of the chilli products including seeds, so that finally it leads to spoilage of products and failure of the seed germination. Several countries are denying the exports on the grounds of contamination of dried chillies due to mycotoxins. Indian chillies are especially uncompetitive in export market due to the severity of this problem. Chemical-free hermetic storage technologies may safe, cost- effective protection of stored red chillies against damage by Aspergillus spp. and mycotoxins. The triple layer plastic bags provided an improved alternative for insecticide-free, long-term storage of common beans, groundnuts, and other garains also with minimal grain damage. First time we have evaluated them and found hermetic safe storage of dry chillies with zero incidences of aflatoxins over a period of six months. Introduction Chilli (Capsicum annuum L.) is an important commercial spice-cumvegetable crop belongs to the family solanaceae, having chromosome number 2n=24 and originated in South America. It is grown in India under various agro climatic conditions viz., tropical, sub- tropical and temperate climates (Hazra et al., 2011). India is the major producer, consumer and exporter of chilli, covering an area of 0.774 million hectares with a production of 1.492 million tonnes averaging a productivity of 1.93 tonnes per hectare (Anon., 2015). The genus Capsicum consists of a diverse range of plants and fruits, and varies enormously with respect to morphology, yield and nutrition related parameters. Chillies are grown as annual crop, although it can also be grown as perennial shrub in suitable climatic conditions. Among the five cultivated species C. annuum is the most widely cultivated species for its pungent (hot pepper) and non-pungent (sweet pepper) fruits throughout the world. Page | 57
The presence of capsaicinoids is specific to the genus Capsicum, which varies widely among the varieties, seasons, places of origin, etc (Prasath et al., 2007). Usually the chilli fruits are consumed at different ripening stages such as green, red or partial red-ripe. Telangana State occupies second position in production (279.8 tonnes) and third position in area (78.9 ha) with productivity of 3.54 t/ha. Dried chillies with a moisture content of 10%, consists of protein (15g), Fat (6.20g), Minerals (6.10g), Carbohydrates (30.20g), Energy (246 k cal), Calcium (160mg), phosphorus (370mg), Iron (2.300mg), Carotene (345µg), Caloric value (297), Riboflavin (0,430mg), Niacin (9.500mg), Vitamin C (50.000mg), Sodium (14.000mg), Potassium (530.000mg), Phytin Phosphorus (71.000), Thiamine (0.930 mg), Mg, Cu, Mn, Zn, Cr, and Oxalic Acid (nill) per every 100 grams. World Production Scenario The largest producer of chillies in the world is India accounting for 13.76 million tonnes of production annually. In India, Chilli was grown in an area 774.9 thousand hectare and production 1492.10 thousand tonnes and the productivity was 1.93 tonnes per hectare in 2014-15 (R. Geetha, and Dr. K. Selvarani., 2017). If the country is able to meet the strict quality demands of the international market, the exports can be further improved. Necessary steps have to be taken by the Government encouraging the exporters to maintain the Indian dominance in the world market. World chilli production is primarily concentrated in South Asian countries to an extent of about 55% of total world production. India is the single largest producer contributing for about 38% followed by neighbors China with 7%, Pakistan and Bangladesh contributing for about 5% each. Rest of the output is spread across South American countries and African countries.
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World Export Scenario Further, India is the largest exporter of chillies, meeting nearly half of the world's consumption demand. Apart from India, China also exports to an extent of about 19% of total exports chilli exports in the world. Peru contributes for nearly 9%, while Spain is the fourth largest exporter in the world as per the data provided by the FAO. Rest of exports are scattered across a number of countries each contributing in minor quantities. Table 1: Top five trading countries in the world
Major importers include the U.S. with about 24% followed by Malaysia with 12% and Sri Lanka with 9% of total imports in the world. Interestingly, Spain is not only fourth largest exporter but also the fourth largest importer as well. Export Details of Chilli from India (Source: Spice Board of India) Chilli Export From India (Quantity in Tonnes & Values in rs. Lakhs) S. No
Year
Quantity
Value
1
2013-14
312,500
272,227.20
2
2014-15
347,000
351,710.00
3
2015-16
347,500
399,743.97
4
2016-17
400,250
507,075.00
5
2017-18 (Est)
443,900
425,633.00
Major Item/Country-Wise Export of Chilli from India (Qty in M.T; Value in Rs. Lakhs) (Source: Spice Board of India) 2013-14
2014-15 2015-16
2016-17
Qty Value
Qty Value Qty Value
Qty Value
Vietnam
32485.31 35856.67 51829.10 63537.42 58842.62 78559.98 70012.51 95929.40
Thailand
21849.64 30141.15 47703.06 45184.38 59916.14 70671.43 60008.77 96101.18
Sri lanka
44360.83 28679.84 49900.51 38783.78 46508.50 50120.24 51392.56 52053.02
Malaysia
35580.69 36416.93 33868.09 38144.86 30994.31 40031.33 28791.87 44187.47
U.S.A
21076.37 29080.69 23109.12 31652.51 24074.47 37846.45 20792.36 39172.20
U.A.E Indonesia Mexico
9207.10
13319.26 18049.71 12774.48 33786.07 23689.53 38318.37 28636.36
18095.24 14150.42 17479.58 15545.03 19855.60 22115.91 33393.85 40934.35 7709.38
9098.30 13280.30 16377.14 10588.70 14719.16 13105.64 20309.50
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6694.74
8714.88
6829.83
Bangladesh 43578.29 32647.89 41916.79 32977.11 14426.43
U.K
5307.78
6724.79
5053.62
6825.68
5614.20
39685.52 32720.04
10302.88
Singapore
3306.37
4009.67
3826.15
4274.90
3432.36
4314.95
3277.36
5086.01
Nepal
5909.14
3432.97
6327.72
4384.13
5167.96
4143.29
8812.20
7042.87
Saudi arabia
5192.72
3650.93
4091.13
3559.05
2017.01
2829.59
2426.70
3416.21
Qatar
1354.57
1024.48
1965.70
1532.94
3571.49
2696.30
3364.55
3564.58
Canada
1259.28
1685.44
1313.34
1760.85
1471.75
2267.06
1463.72
2634.63
China
3531.51
3170.85
2378.34
2469.37
2029.35
2211.42
2399.90
2723.48
Australia
1206.78
1574.62
1294.84
1719.61
1356.77
2136.23
1587.35
2861.85
Oman
2353.37
1493.49
2031.39
1501.69
2226.85
2071.60
1843.84
2298.30
South africa
2508.30
2906.01
2881.12
3252.30
1483.85
2034.59
2022.64
3540.41
Total (Incl. 312500.00 272227.20 347000.00 351710.00 347500.00 393170.00 400250.00 507075.00 Others)
Domestic Scenario India, as observed in the earlier section, is the largest producer, consumer and exporter of chillies in the world. India produces on average 1.3 to 1.5 million tonnes of red chillies annually. India is the largest consumer of chilli in the world. Nearly 80% of India's production is consumed within the country and only about 15-20% of domestic production is exported. Trends in area and production during the last two decades indicate that there is a significant rise yields per hectare particularly from 2003-04 onwards and it has led to a sharp increase in production level from less than one million tonne to 1.2 million tonnes in late 2000s. However, Area under chilli cultivation has largely remained the same hovering around 8 lakh hectares throughout 2000s and after. Several different varieties of chiles are cultivated for various economic uses like vegetable, pickles, spice, condiments and doubling as a nutraceutical crop (Geetha et al., 2017). As of the year 2014, India ranked 1st in dry chili production (1.49 Mt) and 17th in green chili (0.69 Mt) in comparison to China, Indonesia and Egypt are the 1st three contenders, respectively (FAO, 2014-15). Considering the Indian scenario in the year 2014-15, estimates suggest that Telangana is the 2nd largest producer of dry chilies (0.3 Mt), following Andhra Pradesh and the 6th largest producer of green chilies (0.09 Mt) following Karnataka, Bihar, Andhra Pradesh, Jharkhand & Haryana, respectively. Productivity wise, Telangana ranks 3rd at 3.54 t/ha followed by Andhra Pradesh (4.58 t/ha) and Uttarakhand (3.60 t/ha), respectively. The average productivity in Khammam district was 3453 Kg/ha and production was 11.318 t, respectively (Velayutham, L.K. and Damodaran, K., 2015). Collars are an important ingredient in many different Page | 60
cuisines across nations adding pungency, taste, flavor and color to food. Indian chili is acclaimed for its color and pungency levels. Some varieties are famous for the red color and others for quality parameters in Chile like length, width, skin thickness and antioxidant compounds (Howard et al., 2000). A wide spectrum of antioxidants viz. Vitamins, carotenoids, capsaicinoids and phenolic compounds are present in hot pepper fruits. The intakes of these compounds as food, supplement health-protection against several diseases. As consumption continues to increase, hot peppers could provide important amounts of nutritional antioxidants in the human diet. Green chilies are rich in proteins 2.9 g per 100 g. Ca, Mg, P, K, Cu and S. Vitamins like Thiamine, Riboflavin and Vitamin C. Major Spice/State Wise Area and Production of Spices (Area in Hectare, Production in Tons) (Source: Spice Board of India) State
2012-13
2013-14
2014-15
2015-16
2016-17 (Est)
Area Production Area Production Area Production Area Production Area Production Andhra 204000 761000 131316 601990 134960 739620 156055 618420 206000 883000 pradesh Telangana
78935
279770
73270
253260
Karnataka 100729 107000
89556
111540
95450
118490 102290 103242 102290 103242
81597
227610 120160 337005
Storage Problems in Dry Chillies The safe storage of a particular produce for considerable period depend up on the fact the probable damage the produce is prone due to biotic or abiotic factors during storage. Fundamentally it is to be taken into consideration that for any grain ecosystem, the most important abiotic conditions influencing biotic activity viz., insect attack, mould growth and mycotoxin production are water activity, temperature and gas composition (Magan et al., 2004). Chillies are produced in countries with tropical climates that have high range of temperature, humidity and rainfall. The crop suffers in the field as well as in storage losses. Traditionally, red chillies are spread out on the surface of ground/polythene sheets/concrete floors to dry in the open air, where the climatic conditions are ideal for growth of molds and production of mycotoxins. Effect of Afflatoxin on Dry Chillies Quality The losses may ranges from 70-80 percent of total quantity due to sun drying. The occurrence of moulds and mycotoxins can be alleviated by the application of variety of preventive measures i.e. good harvesting and Page | 61
storage practices. Aspergillus sp. is commonly found on chilli fruits stored in humid region. Aspergillus flavus is predominant component of the mycoflora of red chilli. The occurrence of moulds and mycotoxins can deteriorate the viability of the chilli products including seeds, so that finally it leads to spoilage of products and failure of the seed germination. Several countries are denying the exports on the grounds of contamination of dried chillies due to mycotoxins. Indian chillies are especially uncompetitive in export market due to the severity of this problem. Chemical-free hermetic storage technologies may safe, costeffective protection of stored red chillies against damage by Aspergillus spp. and mycotoxins. Aflatoxin is a chemical produced in chillies due to fungal causal organisms i.e., aspergillus flavus and apergillus parasiticus. It comes in chillies during picking, drying, handling, packing, and transportation because of the metabolic activity of fungus, physical rupturing and insect damage. Aflatoxin is one of the sources of primary liver cancer (PLC) in human and animals. According to the World Trade Organization (WTO), the international aflatoxin permissible level is less than five parts per billion (ppb). The postharvest management of chillies comprises picking, handling, drying and grading, packing, storage and transportation. An aflatoxin free chilli is only possible by proper picking, good handling practices, necessary improvement of traditional sun drying practices, introduction jw3rof commercial scale mechanical dryers, isolation of old and new chillies, proper grading and storage. Chili crop does not mature at one time and ripe crops should be harvested at frequent intervals. The most important factors affecting aflatoxin formation are moisture, temperature and insect and physical damage. During picking, the chillies must avoid the direct contact with dew and rain. Ill handling is also one of the major causes of aflatoxin contamination to chillies which can be ameliorated by orientation and creating the awareness among growers to produce the internationally acclaimed product. Careful handling from picking to transportation results in minimum injured, broken or ruptured produce. Quality regarding aflatoxin also depends on drying. Fresh picked chillies have unsafe moisture content which results in heating of the fruit and rapid deterioration. To avoid microbial activity and aflatoxin production, the Page | 62
moisture content in dried pods should not exceed 10 per cent by weight. There are two methods of drying i.e., sun drying (natural drying) and artificial drying (mechanical drying). During the dry season, sun drying is usually simplest and cheapest method to dry chillies. In this method the produce is spread on an open floor or roof of the building and exposed to sun for 10–15 days. However, some problems are associated with this method. Dust or dirt is blown onto the crop which contaminates and unexpected rainstorms can re-wet the produce, which activates microbial activity and ultimately aflatoxin contamination. Description of PICS Bag In 1987, Professor Larry Murdock of Purdue University, in partnership with Bean/Cowpea CRSP, USAID, and BIFAD, led a team of researchers working to combat bruchid infestations of cowpea harvests in Cameroon. The outcome of this initiative were PICS bags. Formerly Purdue Improved Crop Storage (PICS) bags (formerly Purdue Improved Cowpea Storage bags) provide a simple, low-cost method of reducing post-harvest cowpea (Vigna unguiculata) losses due to bruchid infestations in west and central Africa. A PICS bag consists of two layers of polyethylene liners and a third layer made from woven polypropylene. When each layer is tied and closed separately, it creates a hermetically sealed environment for storing harvested produce. This oxygen-deprived environment proves fatal for insect pests and molds present in the stored produce. Triple layer plastic bags developed recently by Purdue University, USA under the Bean/Cowpea Collaborative Research Support Program (CRSP). These triple layer plastic bags provided an improved alternative for insecticide-free, long-term storage of common beans with minimal grain damage (Murdock et al., 2003). Triple layer plastic bags consists of three layers; inner and middle layers were made up of 80 micron thickness high density polyethylene (HDPE) material and do not allow diffusion of gases (Oxygen and Carbon dioxide) while the outermost layer is a normal woven sac made up of polypropylene and provides strength for handling.
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Different Layers of Triple Layer Plastic Bag
Advantages of PICS Bag PICS bags provide many benefits to smallholder farmers. Not only is this an effective insecticide/fungicide-free, low-cost method of storing cowpeas and other harvested dried produce, but it is easy to explain to farmers, and PICS bags can be stored in family homes– making this an effective way for smallholder farmers to protect their harvests. In addition, the bags can be opened at any time – when they are unsealed the stored produce are ready to be consumed. The PICS bags can then be reused (Boaua et al., 2012 conducted extensive studies on different types of PICS bags: (1) new 50 kg (2) new 100 kg bags and (3) once-used 50 kg bags. After five months of storage, new and used 50 kg bags and new 100 kg bags preserved the grain equally well) provided they are free of holes and tears. Studies have demonstrated that PICS can be used multiple times across several years without any loss in quality.
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Storing produce until it reaches a high market value allows farmers to gain greater profits, and storage provides communities with food reserves during the post-harvest season. Even after several months of storage in PICS bags, the quality of the grain does not decline. How to use PICS Bag After harvesting and thoroughly drying the produce, farmers place produce into a polyethylene bag capable of holding either 50 kg or 100 kg. The bag is then tightly sealed, preventing air from entering. The first polyethylene bag is surrounded by a second identical bag, which is also sealed, making it airtight. The double-bagged grain is then sealed inside a third woven polypropylene bag, which provides the mechanical strength for PICS bags. This method of triple bagging creates an airtight environment, and seals any insects/molds present in the crop inside the bag. These insects/molds briefly continue to consume oxygen, but as oxygen levels in the bags drop, and CO2 concentrations rise, the insects/molds stop feeding and quickly die, thereby protecting the crop from further damage (Anankware and Ire., 2013, Macro et al., 2014, Navarro et al., 2014, Vales et al., 2014 and Njoroge et al., 2018). Economic Development The PICS project aims to increase the incomes of smallholder producers. Each household that adopts the use of PICS bags is expected to save $150 (USD) annually. With wide spread adoption of PICS bags, global savings of cowpea harvests are predicted to be worth half a billion US dollars annually. The additional income provided through the use of PICS bags will allow smallholder producers to invest in their own farming practices and local communities, thereby encouraging local development.
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Storage of Dry Chillies by Using PICS Bags The other traditional structures like underground pits effectively control the insect pests as they create airtight environment but the produce is liable to theft by thieves and also need to have proper drainage facilities during rainy season. An improved traditional storage tool currently being used by farmers on a large scale includes jute bags as they are easy to handle but they are highly porous in nature and absorbs moisture and allows free exchange of gases from atmosphere leading to attack of pests. Further, plastic polythene bags do not absorb the moisture but they are sensitive to sunlight and deteriorate the produce. Metallic bins, as they are more resistant to insect attack by creating closed environment but require more space to storage. Considering the limitations associated with traditional and improved storage structures a more recent technique was developed known as controlled atmosphere storage technique which works on the principle of hermetic storage technology targeting the respiratory biology of a living organism. Every living organism requires oxygen to survive by inhalation of oxygen with exhalation of carbon dioxide to continue its metabolic activities. In pest management perspective, the amount of oxygen required to complete the life cycle of an insect is essential to estimate what percent depletion of oxygen prompts the insect to die due to hypoxia (reduced levels of oxygen) and hypercarbia (increased levels of carbon dioxide) (Vales et al., 2014, Martin et al., 2015 and Boaua et al., 2012). Baribusta et al., 2017 reported that after storage, in PICS bag the average O2 level fell from 21% to 18% (v/v) and 21% to 15% (v/v). In this way it is useful to devise management practices that avoid the usage of insecticides as they leave hazardous residues on stored products. The controlled atmosphere storage technology was found to give good control of storage insect pests without usage of chemical insecticides but, the very draw back about the technology was creation of a modified environment by changing the gas compositions artificially using vacuum cylinders in the storage structures and thus making the technology nonpractical at farmers’ level. An improvement of the above technology following the hermetic storage principles is the use of triple layer plastic bags developed recently by Purdue University, USA under the Bean/Cowpea Collaborative Research Support Program (CRSP). These triple layer plastic bags provided an improved alternative for insecticide-free, long-term storage of common beans with minimal grain damage (Murdock et al., 2003). Repeatedly breaking the hermetic seal of the PICS bags will increase
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fungal growth and the risk of aflatoxin contamination (Timothy et al., 2016). First time in world we, evaluated the PICS bags for hermetic storage of dried chillies. Five kilograms of dried chilles with moisture per cent of 10 were weighed separately and placed in each of four bags viz.,1) Jute bags (2) Polythene bags (3) Triple layer plastic (PICS) bags and (4) Jute bags treated with insecticide Mancozeb. Each of these bags will be infected with spore suspension of Aspergillus flavus toxigenic strain (AF 11-4) @ 15 ml/bag. The bags were then moved gently upside and down for uniform mixing of fungus infected dried chillies before closing the bags. The storage bags (one layer at a time starting with the inner most in the case of triple layer bags (PICS) were sealed with heat sealer without any air present inside the bag then middle layer is sealed, finally the outer polypropylene bag is tied with thread tightly which gives protection to the inner two layers. Each of the four bags used for the experiment were replicated thrice at same moisture percentage of 10%. Hence, a total of 36 such storage bags were formed in the experiment, which were tested for Aspergillus flavus development, moisture content, germination percentage, protein content, carbohydrate content and fat content in the seed after an interval of 2, 4 and 6 months of storage. With respect to aflatoxin accumulation, the initial aflatoxin content recorded was 0 ppb. Among different types of storage bags, there is no aflatoxin accumulation was recorded in triple layer plastic bag (0 ppb) and jute bag treated with fungicide (0 ppb). The maximum aflatoxin accumulation was recorded in jute bag (4 ppb). Triple layer plastic bag (0 ppb) and jute bag treated with fungicide (0 ppb) were at par and recorded no aflatoxin accumulation. Among different set of storage periods such as 2, 4 and 6 months, the minimum aflatoxin accumulation was recorded in the 2 months storage period (1.25 ppb) followed by the 4 months storage period (1.75 ppb). The maximum aflatoxin accumulation was recorded in 6 months storage period (2.25 ppb). All the storage periods were significantly different (P
