journal of agricultural engineering

ISSN : 0256-6524

VOL. 49, No. 2

April-June 2012

JOURNAL OF AGRICULTURAL ENGINEERING

INDIAN SOCIETY OF AGRICULTURAL ENGINEERS ISAE

2nd

Indian Society of Agricultural Engineers Editorial Board

Chief Editor: Dipankar De ([email protected] Farm Machinery and Power Division

Processing, Dairy and Food Engineering Division

Soil and Water Engineering Division

Energy and Other Areas Division

Editor

A.P. Srivastava [email protected]

S.D. Kulkarni [email protected]

S. K. Gupta M. Shyam [email protected] [email protected]

Associate Editors

L.P. Gite V.M. Duraisami Atul Srivastava G.S. Tewari P.K. Sahoo

D.C. Joshi Jaswant Singh Lalan K. Sinha Ravindra Naik S.K. Jha

Satyendra Kumar P.K. Singh Madan K. Jha D. K. Singh

N.S. Rathore Y.K. Yadav

Publication Enquiries The journal of Agricultural Engineering, a publication of the Indian Society of Agricultural Engineers, is published in four issues per year. This journal is not responsible for statements and opinions expressed by the authors of papers published in it. Reprints may be made from this publication on the condition that full credit is given to the author(s) and the Journal of Agricultural Engineering. All communications regarding the publication or submission of manuscripts should be addressed to The Chief Editor, Journal of Agricultural Engineering at the address given below.

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Journal of Agricultural Engineering Vol. 49(2): April - June, 2012

Effect of Peening Intensity and Applied Load on Low Stress Abrasive Wear Response of Agricultural Grade SAE-6150 Steel Dushyant Singh1, DP Mondal2 and V.K.Sethi3 Manuscript received: March 2011

Revised manuscript accepted: March, 2012

ABSTRACT The effect of shot peening on low stress abrasive wear behaviour of SAE-6150 steel was studied at various intensities varying from 0.17A to 0.47A. The abrasive wear test on un-peened and peened specimens by dry sand abrasion tester revealed that shot peening reduced abrasive wear considerably, when it was restricted up to 0.17A. But over peening led to higher abrasive wear rate. In the critical period, the peened and un-peened samples exhibited comparable wear rate, indicating that peening was required on regular interval to maximize the advantages. The technology would be useful for manufacturer of agricultural implements in India, due to its simplicity and cost effectiveness. Key words: Peening, abrasive wear

Medium carbon steels are used for various engineering and agricultural applications. In fact, these steels are used in high volume in tillage/soil working implements (Bliesener, 1953) like cultivator sweep, furrow opener of seed drill, ploughshare, etc. The rapid wear of these machine parts is responsible for most of idle time for maintenance as well as expenditure on repair and manufacturing of spare parts (Foley et al., 1994). A large fraction of agricultural implements in India is fabricated by the small scale sector, which generally face problems of non availability of proper material, inadequate manufacturing process and quality improvement techniques. The Government of India in its report stressed for more research and development activities on the design and quality production of agricultural implements (Anon, 1986). To overcome the effects of these adverse factors (dynamic loads, abrasive wear and chemical action), various attempts have been made to improve the surface properties (specially hardness) of soil-engaging components such as diffusion coating, hardfacing (weld deposit) and enamel coating. Commonly used diffusion process by the investigators for life extension of fast wearing components of agricultural implements are carburizing (Rautaray,1997; Varshney, 2000; Saxena and Sharma, 2001; Moore,1975) nitriding, carbonitriding (Moore,1975) and boriding (Moore, 1975; Er and Par, 2006). The relative wear resistance of carbonized and nitrided materials used for soil working components of agricultural implements were found similar to that of a high carbon steel of same hardness. A regular cultivator sweep tested with five kinds of hardfaced sweeps indicated that the wear in all hardfaced sweeps were considerably less in comparison to regular

sweep. But, the extents of wear are different in different kinds of hardfacing (Zhang and Kushwaha, 1995). The wear rate in soil working components of agricultural implements like tine point, subsoiler, plough land slide and mole plough with alumina protection are reported to be five times lower than that of conventional steel components (Foley et al., 1994). Hardfacing by weld deposit on the surface of soilengaging components is more useful in sliding wear in weak soils with low stone content (Moore, 1979). In hardsurfacing of cultivator shovel, a single-layer deposit is reported to be satisfactory. Hardsurfacing shovels with electrodes Modi 600, Lomet 304,Cromcarb N6006, Lomet 303 and ultimium N112 exhibited reduced wear in the order of electrodes listed (Raval and Kausal, 1990). Hardfacing is a very effective and techno-economic solution for wear problem (Kumar et al., 1999; Kumar et al., 2000). Various enamel coatings were also used in agricultural implements to reduce draft requirement, improving scoring and to minimize wear (Foley, 1988; Salokhe and Gee clough, 1988; Salokhe et al., 1989). Enamel coated plates have shown excellent non–stickiness to the soil in actual field conditions (Salokhe and Gee Clough , 1988). All these processes are cost and energy intensive, as new materials are deposited and considerable amount of electrical energy is required. Shot peening is reported to be an appropriate technique to improve the strength of metal, which indirectly improves wear resistance without using alloying or other processes that changes the bulk microstructures of materials due to surface work hardening (Yan et al., 2007). As shot peening is also a surface work-hardening process,

Scientist (SS), Central Institute of Agricultural Engineering, Bhopal-462038, Bhopal, 3 IIIT, Rajiv Gandhi Proudyogiki Vishwavidayala, Bhopal. 1

2

Advanced Materials and Processes Research Institute,

April - June, 2012

Effect of Peening Intensity and Applied Load on Low Stress Abrasive Wear Response of Agricultural Grade SAE-6150 Steel

it is expected that considerable improvement in wear resistance could be achieved due to application of the technique. Singh and Saxena (2008) examined the effect of heat-treatment and shot peening on 50B50 boron steel at 75N load, and found that heat-treatment cycles as well as shot peening intensity significantly affected the wear rate of 50B50 boron steel. Presently, boron steels are commonly used for manufacturing of agricultural implements only in developed countries, as its cost is higher and are not easily available in developing countries like India. Heat-treatment is again a costly process to alter the properties of a material. Keeping this in view, medium carbon steel (SAE-6150), commonly used for making fast-wearing components of agricultural implements in India, was selected to understand its wear behaviour in “as-received condition” (without heattreatment) with and without shot peening process at three different loads of 75, 200 and 375N.

Fig.1: Measurement of shot peening intensity

samples were used for hardness measurement. Opposite surfaces of the samples were made parallel to each other prior to hardness measurement. As per standard procedure, a load of 294 N was used for making the indentations. Micro-hardness measurements were carried out on polished and etched surfaces of the samples with the help of a digital microhardness tester (LECO: Model DM-400). A Scanning Electron Microscope (SEM) was used to examine the microstructure of peened and un-peened specimens.

MATERIALS AND METHODS Chemical Characterization of Steel and Shot Peening Medium carbon low alloy SAE-6150 steel was used in the study. Its chemical composition is given in Table 1. Table 1. Chemical composition of steel used Specification

Chemical composition (weight, %)

SAE-6150 steel

C

Si

Mn

Cr

V

0.52

0.22

0.70

1.0

0.17

Low stress abrasive wear tests Low stress abrasive wear tests were conducted using a dry sand abrasion tester as per ASTM-65 standard. Before starting the wear tests, the specimens were cleaned and polished according to standard metallographic techniques, weighed by an electronic balance, and then fitted in specimen holder. The test was started and as the machine stopped after completion of preset revaluations; the specimens were taken out, cleaned and weighed. This process was repeated for 18 times (200 revolutions, or 144m each time) to examine the wear trend of the specimen. The specimens (“as received” and shot peened) were tested at three loads (75N, 200N and 375 N). The wear rate was calculated from volume loss. This test methodology very well simulates with the working condition of fast wearing components of agricultural machinery as shown in Fig. 2. The test specimen was pressed against a rotating rubber wheel, while a controlled flow of abrasives was maintained at the test surface. The duration of the test and the applied load was varied as per the experiment requirements. Crushed silica sand particles (size 212-300mm) at the rate of 370 g.min-1 were applied for abrasive action. During the tests, a constant sliding speed of 1.86 m.s-1 was maintained.

Shot peening Shot peening was carried out at various peening intensities ranging between 0.17A and 0.47A by shot-peening (Mech Shot, Jodhpur, India) machine. Standard “A” type Almen strips were used to measure the peening intensity. The expose time was varied, keeping other parameters constant, for obtaining different peening intensities. The methodology of shot peening intensity measurement is given in Fig. 1. The peening intensity as a function of peening time is shown in Table 2. Table 2. Peening intensity as a function of peening time

Peening intensity (A) Expose time (s)

0.17

0.27

0.37

0.47

18

25

55

120

Measurements Hardness, microhardness and microstructure of material The hardness of test piece materials was measured before and after shot peening by a Vicker hardness tester. Polished 2

Dushyant Singh, DP Mondal, V.K.Sethi

JAE : 49 (2)

noted to be 150HV. The micro-hardness of steel at the subsurface after shot peening is given in Table 3. It revealed that the subsurface microhardness increased with increase in peening intensities, which indirectly suggested that work hardening of the surface took place due to shot peening. The microstructure of shot peened surface showed dents and leaps (marked ‘D’, Fig. 3(b)). The microstructure of heavily peened specimen at the surface showed extensive micro-cracking marked ‘arrow’ as depicted in Fig. 3(b). Effect of sliding distance on abrasive wear The variation of abrasive wear with sliding distance is depicted in Fig. 4, Fig. 5 and Fig. 6 at 75N, 200N and 375N, respectively. It could be noted that wear rates were decreasing with sliding distance, and obtained a steady state value. The initial wear rate was higher either due to presence of foreign material at the surface of un-peened specimens or presence of weaker leaps on the peened specimens, which were removed at faster rate during wear. The continuous plastic deformation caused surface work hardening and it could be expected that the wear rate would reduce monotonically with sliding distance. However, other phenomena like surface and subsurface cracking annihilated this effect after some time when the surface work hardened excessively. Under steady state condition, the wear rate of mild peened (0.17A) samples were found

Fig.2: Abrasion tester (in conformity of ASTM G65)

RESULTS AND DISCUSSION Materials and Microstructures The microstructure of SAE-6150 steel exhibited two-phase structures of ferrite (F) and pearlite (P) in which the pearlite colonies were more or less surrounded with ferrite network as shown in Fig. 3 (a). In this ferro–pearlitic structure, the pearlite is a harder phase and the abrasive wear is controlled by the amount and distribution of this pearlitic phase. The volume fraction of ferrite and pearlite phases was found to be 20% and 80%, respectively. The hardness of steel was

Table 3. Micro-hardness (MH) of steel at the subsurface after shot peening Peening intensity, A Parameter

unpeened

Depth, mm

-

0.0

0.1

0.2

0.3

0.0

0.1

0.2

0.3

0.0

0.1

0.2

0.3

0.0

0.1

0.2

0.3

150

190

172

154

150

215

183

169

152

240

203

182

156

270

232

194

159

MH, HV

0.17

0.27

(a) Un-peened Fig. 3:

0.37

0.47

(b) Peened at high intensity

Microstructure of as received un-peened and peened SAE-6150 3

April - June, 2012


Fig.4: Effect of sliding distance on wear rate of SAE-6150 steel at 75N

Fig.5: Effect of sliding distance on wear rate of SAE-6150 steel at 200N

Fig.6: Effect of sliding distance on wear rate of SAE-6150 steel at 375N 4


JAE : 49 (2)

to be about 35 %, 28.83% and 38.39% less in comparison to un-peened specimens at 75N, 200N and 375N loads, respectively. The wear behaviour of SAE-6150 steel is almost similar under varying applied loads. The reduction in wear rate due to mild peening occurred due to improvement in surface hardness (Table 3). This resisted the penetration of sand particles and development of residual compressive stresses at the surface and sub-surfaces that resisted crack formation and crack initiation at the surface and subsurface level during peening. Further increase in peening intensity led to crack formation and increased brittleness at the surface and subsurface level, which led to more severe wear.

applied load was expected. However, Fig. 7 demonstrated that the trend in variation in wear rate with applied load was almost invariant to peening intensity. With increase in applied load, the depth of penetration increased which led to more material removal. The figure also indicated that the steel exhibited minimum wear rate when subjected to peening at intensity of 0.17A, irrespective of the applied load. Further increase in peening intensity led to more wear, which is discussed in later section. Effect of peening intensity on abrasive wear The effect of peening intensity on abrasive wear of SAE6150 steel at three loads of 75N, 200N and 375N are shown in Fig. 8. It is evident from the figure that wear rate decreased initially with increase of peening intensity up to 0.17A.

Effect of applied load on abrasive wear The effect of applied load in abrasive wear of SAE-6150 steel is depicted in Fig. 7. The increase in wear rate with

Wear rate, m3.m-1 X10-11

Fig.7: Effect of applied load on abrasive wear of “as received” SAE-6150 steel

Peening intensity, A

Fig.8: Effect of peening intensity on abrasive wear of “as received” SAE-6150 steel 5

April - June, 2012


Further increase in peening intensity led to increase in wear rate. It could be observed from Fig. 8 that minimum wear rate could be achieved with peening intensity limited to 0.17A. At considerable higher peening intensity, the wear rates of material were considerably higher, and sometimes even higher than that of un-peened specimens. The extent of improvement in wear resistance due to mild peening was due to higher surface and subsurface hardness (Mondal et al., 2008; Singh et al., 2010), which might have been achieved due to work-hardening and micro-structural refinement. Compressive residual stress developed on the surface due to shot peening reduced micro-cracking tendency during wear on the surface (Lida, 1996; Yan et al., 2007). Higher peening intensity made the surface saturated with work-hardening and caused surface and subsurface micro-cracking either during peening or wear test due to application of load. The dents and leaps formed during peening got damaged during severe peening, and thus easily removed. Furthermore, surface and subsurface cracks developed during peening started growing further and interacted with each other, leading to delaminating wear in addition to the abrasive type wear. The subsurface being significantly work-hardened during peening, only minimum amount of energy was spent on the surface and subsurface deformation, and major extent of energy was consumed for abrasion. All these facts led to increase in the wear rate at higher peening intensity. Thus, it could be recommended that higher peening intensity should be avoided for obtaining improved wear resistance.

expected that after removal of material up to this depth, even the shot peening material would behave similar to that of un-peened material. In this context, comparison of wear rate of un-peened and peened (0.17A) specimens of SAE-6150 at different intervals was examined, and shown in Fig. 9. It is exhibited from the figure that the wear rate of peened (0.17A) specimen in the initial intervals were significantly less than that of un-peened samples. In later intervals, the difference in the wear rate amongst the peened and un-peened samples reduced and after a critical distance of about 1700 m, both the peened and un-peened samples exhibited almost similar wear rate at each proceeding intervals. This demonstrated that the effective depth of peening got removed after sliding up to 1700 m. The effect of shot peening towards wear behaviour became inactive after a sliding distance of about 1700 m. This further suggested that the overall improvement in the wear rate in shot peened and un-peened samples was due to significant influence of peening in the initial stages of the wear behaviour, which caused considerable decrease in wear rate in the initial sliding period. In fact, a critical depth from the peening surface of the specimen got subjected to plastic deformation during peening and the influence of peening was limited to this depth only. After a certain distance (about 1700 m in the present study) the layer influenced by shot peening got completely removed and thus, beyond this sliding distance, even the shot peened samples behaved similar to the un-peened samples. This further suggested that in order to have continuous improvement in the wear resistance, the material could be shot peened intermediately during its operation.

Peening leads to microstructural refinement and surface work-hardening up to limited depth. As a result, it is

Fig.9:

Comparison of wear rate of “as received” SAE-6150 steel peened and un-peened condition (at 200N load) at different intervals 6


JAE : 49 (2)

CONCLUSIONS i.

Mondal D P; Vinod E M; Das S; Rao T S V. 2008. High stress abrasive wear behaviour of shot peened AA2014 Alalloy. Indian J. Eng. Mater. Sci., 15, 41-50.

Wear rate decreased with sliding distance irrespective of peening intensities and applied loads. Wear rate increased monotonically with increase in applied load, irrespective of peening intensity.

Moore MA. 1975. The abrasive wear resistance of surface coatings. J. Agric. Eng. Res., 20, 167–179. Moore MA; McLees; King FS. 1979. Hard facing soilengaging equipments. The Agric. Engineer, Spring, 15-19.

ii. Shot peening was found to be a suitable surface treatment technology to improve abrasive wear resistance to a great extent.

Rautaray S K. 1997. Fatigue and wear characteristics of shot peened Rotavator blade materials. Unpublished Ph. D thesis, Faculty of Engineering, Barkatullah Vishwavidyalaya, Bhopal, India, 60-61.

iii. Peening up to 0.17A (in this case) was beneficial. Over peening had adverse effect on abrasive wear. iv. Fast wearing components of agricultural implements would require to be shot peened after about 1700 m of travel, as soon as the effected depth from surface gets worn out.

Raval A H; Kaushal OP. 1990. Wear and tear of hard surfaced cultivator shovel. Agric. Mech. in Asia, Africa and Latin America, 21(2), 46-48. Salokhe V M; Gee – Clough D. 1988. Coating of cage wheel lugs to reduce soil adhesion. Agric. Eng. Res., 41, 201-210.

REFERENCES Anon. 1986. Perspective for agricultural tractor industry in India. Report of Working group of Ministry of industry, Government of India, 13-31.

Salokhe V M; Gee–Clough D; Mufti A I. 1989. Performance evaluation of an enamel coated mouldboard plough. Land and water use (Eds.: Dodd and Grace), 16331637.

Bliesener W C. 1953. Farm equipment steels: a tillage implements metallurgist’s viewpoints. Agric. Eng., 34, 697699. Er U; Par B. 2006. Wear of ploughshare components in SAE 950C Steel surface hardened by power boriding. Wear, 261, 251-255.

Saxena A C; Sharma M C. 2001. Wear of shot peened thresher pegs. In: International Conference on Shot Peening and Blast Cleaning (Ed: M.C. Sharma), MACT, Bhopal, India, 281-287.

Foley A G; Chisholm C J; McLees V A. 1988. Wear of ceramic-protected agricultural subsoilers. Tribol. Int., 21(1), 97-103.

Singh, D; Saxena, A.C. 2008. Effect of heat-treatment and shot peening on low stress abrasion wear behaviour of medium carbon steel. J. Agric. Eng., 45 (2), 48-53.

Foley A G; Lawton P J; Barker A W; McLees V A. 1994. The use of alumina ceramic to reduce wear of soilengaging components. J. Agric. Eng. Res., 30, 37-46.

Singh D; Mondal D P; Modi O P; Sethi V K. 2010. Low stress abrasive wear response of boron steel under three body abrasion: effect of heat-treatment and peening intensities. Indian J. Eng. Mater. Sci., 17, 208-218.

Kumar S; Mondal D P; Khaira H K; Jha A K. 1999. Improvement in high stress abrasive wear properties of steel by hard facing. J. Mater. Eng. Perform., 8 (6),711–715.

Varshney A C. 2000. Studies on wear characteristics of materials used as cutting edge for augur digger. Unpublished Ph. D thesis, Faculty of Engineering, Barkatullah Vishwavidyalaya, Bhopal, India, 73, 111.

Kumar S; Mondal D P; Jha A K. 2000. Effect of microstructure and chemical composition of hardfacing alloy on abrasive wear behaviour. J. Mater. Eng. Perform., 9 (6), 649–655.

Yan Weilin Fang; Liang Sun Kum; Xu Yunhua. 2007. Effect of surface work hardening on wear behaviour of hard field steel. Mater. Sci. Eng., 460-461,542–549.

Lida, K. 1996. Historical aspect of shot peening. In: Proceeding of International Conference on Shot Peening and Blast cleaning (Eds.: M.C. Sharma and S.K. Rautaray) MACT, Bhopal, India, 26-29.

Zhang J; Kushwaha R L. 1995. Wear and draft of cultivator sweeps with hardened edges. Canadian Agric. Eng., 37 (1), 41-47.

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Anthropometry of Farm Workers of Kashmir Region of India for Equipment Design Jagvir Dixit1and Deldan Namgial2 Manuscript received: September 2011

Revised manuscript accepted: April 2012

ABSTRACT Anthropometric data (25 body dimensions, relevant to design of farm machinery) of 610 farm workers was collected from Kashmir region of India. The comparison between the Kashmir region data and different regions of India and six foreign countries is presented. There were significant differences in weight, stature and other body dimensions between the populations. Kashmiri women were taller by 31 mm as compared to south Indian female workers, but had differences in hand length. No differences existed between stature eye height, hand length and inside grip diameter among females from Kashmir and North-eastern regions. Kashmiri women were heavier and fatter as compared to other selected regions of the country. Indian men were shorter by 75 mm as compared to Americans. The muscular strength (elbow flexion) of Indian workers was lower (241 N) as compared to Americans (270.7 N). Similarly, hand grip strength of Indian workers was lower (301.8 N) than Americans (398 N). Application of data in design of agricultural equipment is demonstrated. Key words: Anthropometry, body dimensions, hand tools, Kashmir region

equipment easily adaptable by them. Therefore, a study was undertaken during 2004-2006 to collect anthropometric data of agricultural workers of Kashmir region to be used in the design and/or design modification of agricultural tools, machinery and equipment.

Improved equipments play an important role in farm mechanization of a country. Compatibility between size and physical strength of the users, design and dimensions of farm tools and equipment is essential to achieve enhanced performance and efficiency of man-equipment system along with better comfort and safety of operators. Availability of database on anthropometric dimensions of the user population, and its customization for target groups is thus important.

MATERIALS AND METHODS Selection of Subjects Anthropometric survey was carried out in all six districts of Kashmir region of Jammu and Kashmir State of India. Three to four villages were selected from each district. The subjects were selected among farmers and agricultural labourers. As per recommendation of AICRP on ESA, a total of 425 male and 185 female subjects in the age group of 18-60 years of age were randomly selected from each district for the study.

About 49% of the working population in Kashmir region is engaged in agricultural operations involving traditional manual activities associated with lot of drudgery and low efficiency. Equipments have not been designed for majority of the user population due to insufficient anthropometric data, and are liable to cause operational difficulties, fatigue and lower performance. Anthropometric measures vary considerably with factors such as gender, race and age. Considerable difference has been found in Indian and Western anthropometric data (Gite and Yadav, 1989). Application of anthropometric data is, therefore, controlled largely by the anticipated user population. Human population of Kashmir region varies considerably from the rest of the country and J&K state due to factors such as race. Anthropometric data of farm workers of the region are essential for design and development of new tools and

Anthropometric dimensions Keeping into consideration the design requirements of hand tools, animal drawn equipment, tractors, power tillers, self propelled machines and workplaces, a total of 79 body dimensions were identified (Gite and Chatterjee, 1999; ISO 7250, 1996; Hertzberg, 1968). In the standing posture, 49 measurements including 16 vertical dimensions, 9 transverse dimensions, 5 circumferential dimensions, 18

Associate Professor, Division of Agricultural Engineering, S. K. University of Agricultural Sciences and Technology of Kashmir, Shalimar, Srinagar-191121, e-mail: [email protected]; 2Assistant professor, RARS, SKUAST-K, Leh

1

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JAE : 49 (2)

Jagvir Dixit and Deldan Namgial

fore limb measurement and weight were recorded. In the sitting posture, 16 measurements including 8 heights and 8 transverse measurements were taken. In sitting/ standing posture 14 measurements included 7 hind limbs, 3 head dimensions and 4 skin fold dimensions. Standard terminologies were used (Anthropometric Source Book, NASA, 1978) for measurement.

region. However, there were no significant differences in stature between Kashmiri and north-eastern female population. Geographical effect was much stronger when comparing the anthropometric data from this study with the anthropometric data of population from southern, central and western India. The z-test indicated that most of the selected dimensions were significantly different.

Instrumentation

Anthropometric Data for Kashmir Region Farm Workers

An integrated composite anthropmeter (ICA) designed and developed at the Indian Institute of Technology (IIT), Kharagpur, India was used to measure the anthropometric dimensions. It facilitates the measurement of vertical, transverse and circumferential body dimensions in standing as well as in sitting posture. A wooden cone was used to measure internal grip diameter. A steel hole template of 12 different sizes (13-24 mm) was used to measure the diameter of index finger. A portable weighing scale (0-125 kg) was used for body weight. Grip dynamometer and skin fold calliper were used for measuring hand grip and skin dimensions. A vernier calliper (sensitivity of 0.1 mm) was used to measure hand and foot dimensions.

A set of 25 body dimensions, relevant to design of farm machinery, were selected and analysed. Descriptive statistics including range, mean, standard deviation, coefficient of variance and percentile values of each population group are presented in Table 1. Comparison of Kashmir region female workers and other regions of India Z-test was performed to determine the differences between mean values of Kashmir region female anthropometric data and the other regions of India viz. southern, central, western and north-eastern. A total of 16 body dimensions were selected for comparison. The results indicated that Kashmiri women had greater weight, stature, eye height, popliteal height sitting, hip breadth sitting and hand breadth across thumb than the southern, central and western regions of Indian female workers (Table 2). The Kashmiri women were taller in stature (1538 mm) as well as they had high circumferential dimensions of chest and waist as compared to women of southern, central and western India, while they were at par in stature with those of North-eastern female population. They had lower buttock popliteal length, hand length and inside grip diameter in comparison to those of southern, central and western Indian female workers. However, there were no significant differences between stature, eye height, knee height, hand length and grip diameter (inside) among Kashmiri and north-eastern Indian female populations.

Experimental Procedure All subjects were informed about the objectives, measurement procedures and clothing requirement. Data of female workers was collected by well trained women investigators. For measuring body dimensions in standing posture, the subjects stood on base platform of ICA with their feet closed and their body vertically erected, while heels, buttocks and shoulders touched the same vertical plane. ICA was adjusted for height of the subject. Similarly, in the sitting posture, subjects sat with their body vertically erect, while their shoulders and head touched the same vertical plane. In sitting posture, feet of the subject completely touched the base platform. Subjects were bare footed with light clothes during measurement to minimize errors. During the measurement of body dimensions, care was taken to avoid any excessive compression of underlying tissues. Data were recorded in a standard proforma provided by the AICRP on ESA, Bhopal, India.

Comparison of Indian and Western Countries male population A total of 9 matching dimensions were selected for comparison among Indian and western countries populations, and presented in Table 3. The results showed that Indian workers were smaller in weight, stature, chest circumference, popliteal height, buttock popliteal length and hip breadth. Also, the muscular strength (elbow flexion) of Indian workers was much lower (241 N) than American (270.7 N) workers. On an average, Indian workers were shorter by 79 mm than Americans in standing posture. Similar trends were observed by Gite and Yadav (1989).

RESULTS AND DISCUSSION Anthropometric data of male and female farm workers, aged 18-60 years, throughout Kashmir region were collected and summarized. The comparison between the populations from Kashmir region and other regions of India indicated that most of the dimensions were significantly different. Female workers from Kashmir region were significantly taller than the female workers from southern, central and western 9

10

Weight (kg) Stature Eye height Shoulder height Elbow height Metacarpal-III height Scapula to waist back length Arm reach from the wall Bi-deltoid breadth Waist circumference Grip diameter (inside) Sitting height Sitting eye height Grip span Popliteal height sitting Forearm hand length Elbow grip length Hand breadth at metacarpal-III Hand breadth across thumb Buttock popliteal length Hip breadth sitting Elbow- elbow breadth sitting Hand grip strength , N Leg strength, N Steering force, N

Dimension

Range (Min. – Max.) 45.0 (34.0) - 79.0 (70.0) 151.1(132.0)- 184.3(168.9) 133.6(123.0)- 168.5(156.6) 114.4(108.3)- 156.9 (142.0) 87.9 (81.3)- 118.3(112.3) 56.9 (52.0)- 86.7 (76.8) 40.9 (38.0)- 64.9 (54.3) 61.8 (67.3)- 98.2 (90.2) 31.2(30.8)- 52.1(45.6) 62.3(49.5)- 103.1(105.0) 3.9 (2.1)- 10.2 (7.9) 67.2 (61.2)- 100.3 (99.1) 58.1(51.2)- 92.3(89.2) 4.3 (4.1)- 8.6 (8.0) 30.1(31.0)- 58.2 (47.4) 33.2 (31.5)- 55.3 (51.0) 16.7(22.8)- 44.8 (39.2) 6.2(5.3) – 11.9 (10.4) 7.2 (7.1) – 12.2 (10.6) 33.9(29.3) – 54.9 (48.7) 22.0 (26.7) – 36.5 (38.9) 24.5(22.0)- 44.8 (42.3) 117.6 (70.6)- 481.2 (240.3) 190.1(126.5)- 500.3 (394.3) 102.6(76.5)- 442.0 (219.7)

() indicates female dimensions All dimensions are in cm until otherwise specified

S. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 60.0 (52.7) 165.7 (153.8) 154.3 (142.4) 137.0 (127.8) 104.3 (98.1) 71.0 (64.8) 51.6 (47.8) 84.0 (78.9) 41.8 (40.7) 76.3 (76.5) 4.9 (4.4) 83.8 (78.7) 73.2 (68.5) 6.1 (5.7) 42.0 (41.2) 44.5 (42.8) 34.6 (33.4) 8.6 (7.8) 9.9 (7.1) 43.7 (41.7) 31.6 (32.8) 34.2 (33.4) 302.2 (124.6) 355.9 (267.8) 279.9 (127.5)

Mean

Standard deviation 5.1 (5.3) 5.7 (7.5) 5.8 (7.8) 6.0 (7.6) 5.7 (6.4) 6.2 (5.9) 4.3 (3.2) 5.8 (5.0) 3.2 (2.7) 5.4 (6.6) 0.8 (0.7) 6.6 (6.7) 7.1 (6.6) 0.7 (0.8) 3.9 (2.6) 3.4 (2.8) 3.6 (2.4) 0.7 (0.7) 0.6 (0.7) 3.8 (3.2) 2.3 (1.9) 2.5 (2.9) 52.4 (30.4) 55.4 (47.1) 64.5 (26.5)

Coeff. of var., % 4.0 (3.9) 5.1 (6.0) 4.6 (6.2) 4.8 (6.0) 4.6 (5.1) 5.1 (4.8) 3.3 (2.6) 4.7 (4.1) 2.6 (2.1) 4.3 (4.7) 0.5 (0.5) 5.3 (5.3) 5.6 (5.2) 0.6 (0.7) 3.0 (1.9) 2.7 (2.0) 2.8 (1.8) 0.5 (0.6) 0.5 (0.6) 2.8 (2.2) 1.8 (1.4) 1.7 (2.2) 40.2 (23.5) 44.1 (36.3) 49.0 (19.6)

5th percentile 51.5 (44.0) 156.2 (141.5) 144.8 (129.7) 127.2 (115.3) 94.9 (87.5) 60.9 (55.1) 44.4 (42.6) 74.5 (70.6) 36.5 (36.3) 67.3 (65.7) 3.6 (3.3) 72.9 (67.7) 61.6 (57.6) 5.0 (4.4) 35.5 (36.9) 38.8 (38.1) 28.7 (29.4) 7.5 (6.6) 8.9 (8.2) 37.5 (36.4) 27.8 (29.6) 30.1 (28.7) 216.0 (74.5) 264.7 (190.3) 173.8 (83.3)

Table 1. Anthropometric dimensions of male and female agricultural workers of Kashmir region of Jammu and Kashmir 95th percentile 68.4 (61.3) 175.1 (166.2) 163.8 (155.2) 146.8 (140.2) 113.7 (108.6) 81.1 (74.5) 58.7 (53.0) 93.6 (87.2) 47.1 (45.1) 85.2 (97.3) 6.1 (5.6) 94.7 (89.7) 84.8 (79.4) 7.3 (7.0) 48.5 (45.4) 50.1 (47.4) 40.6 (37.3) 9.8 (9.0) 10.8 (10.7) 50.0 (47.0) 35.5 (35.9) 38.2 (38.1) 389.5 (174.6) 449.3(346.3) 386.1(171.7)

April - June, 2012 Anthropometry of Farm Workers of Kashmir Region of India for Equipment Design

11 41.2 (2.6) 48.8 (2.8) 41.7 (3.2) 32.8 (1.9) 16.6 (1.2) 9.4 (0.7) 4.4 (0.7)

Knee height sitting

Buttock popliteal length

Hip breadth sitting

Hand length

Hand breadth across thumb

Grip diameter (inside)

4.5 (0.2)

8.9 (0.4)

16.6 (0.7)

28.5 (2.4)

44.0 (3.1)

47.4 (3.1)

39.5 (3.2)

60.2 (9.2)

77.8 (5.3)

22.2 (2.0)

36.2 (2.7)

44.1 (2.5)

96.5 (4.2)

138.5 (6.4)

150.7 (6.0)

47.2 (8.3)

Southern Indiaa

4.9 (0.3)

8.8 (0.5)

17.2 (0.8)

31.3 (2.5)

45.7 (2.4)

46.9 (2.4)

38.9 (2.3)

77.4 (2.9)

81.2 (7.4)

22.7 (2.7)

36.3 (2.4)

43.3 (2.5)

96.0 (4.0)

141.2 (5.1)

151.2 (5.2)

45.2 (7.3)

Central Indiab

4.5 (0.3)

8.3 (0.5)

16.8 (0.8)

30.4 (2.7)

44.0 (3.2)

46.5 (2.3)

38.9 (2.1)

75.4 (3.1)

79.1 (6.5)

22.5 (2.8)

35.1 (2.4)

43.6 (2.2)

94.3 (3.9)

139.2 (5.0)

151.0 (5.1)

43.2 (7.2)

Western Indiac

4.3 (0.3)

8.8 (0.5)

16.5 (0.7)

31.1 (2.0)

38.1 (2.9)

45.3 (2.4)

35.3 (1.8)

80.2 (3.4)

85.0 (6.4)

24.8(1.9)

42.0 (3.6)

41.2 (2.4)

96.2 (4.2)

141.7 (5.1)

153.2 (5.5)

48.0 (4.4)

North eastern Indiad

Unit: cm unless otherwise stated *significant (p< 0.01) a Kathirvel et al. (2005); bGite et al. (2005); cPowar and Aware (2005) ; dDewangan et al. (2008)

78.7 (6.7)

Waist back length

Popliteal height sitting

41.2 (3.9) 41.3 (3.2)

Knee height

Sitting height

98.1 (6.4)

Elbow height

87.3 (6.0)

142.4 (7.8)

Eye height

Chest circumference

153.8 (7.5)

Stature

27.2 (1.8)

52.7 (5.3)

Weight, kg

Waist breadth

Kashmir region

Body dimension

-1.9

9.3*

0.0

25.1*

-8.6*

5.8*

7.3*

29.7*

19.3*

32.1*

19.6*

-9.5*

3.2

6.2*

5.1*

10.6*

Kashmir Vs. Southern India

-9.2*

10.2*

-6.1*

7.6*

-14.7*

7.7*

10.0*

2.5

10.1*

22.3*

18.4*

-6.6*

4.0*

1.9

4.2*

13.2*

Kashmir Vs. Central India

-1.8

17.6*

-1.9

10.1*

-7.0*

8.7*

9.5*

6.1*

12.8*

19.6*

21.3*

-7.3*

6.9*

4.7*

4.2*

14.7*

Kashmir Vs. Western India

Table 2. Comparison of mean (SD) of anthropometric data of female farm workers of Kashmir region with different regions of India

1.9

10.5*

1.1

9.9*

13.0*

14.7*

27.9*

-2.9*

4.2*

14.7*

-2.4*

0.0

3.7*

1.1

1.0

10.5*

Kashmir Vs. Northeastern India


JAE : 49 (2)

April - June, 2012

Anthropometry of Farm Workers of Kashmir Region of India for Equipment Design

Application of Anthropometry in Design of Farm Tools

Ratio of sitting height to stature (RSH) of male population surveyed was computed and compared with western countries. The RSH ratio was found to be lower for Indian male workers (0.5057) than those of Americans (0.5225 and 0.5218). Gite and Yadav (1989) reported RSH ratio of 0.5172 for Indian population.

It is generally accepted that a mismatch between users and tools can cause musculoskeletal disorders, discomfort and lower the productivity. According to previous experiences and a survey among the professional designers and engineers, not many of those professionals exactly knew how the anthropometric data could be used (Wang et al., 1999). Gite (1999) pointed out that there is large variation in handle height in various models of manually drawn weeder. The design of equipment based on anthropometric dimensions should be carefully selected, as generalization from the sample to the population may be difficult. It may also be noted that anthropometric measurements are taken in static posture. Therefore, the data given in Table 1 should not be used directly for design/ design modification of tools, implements and work places. For this, functional body dimensions which are more representative of human activities are required (Dewangan et al., 2008). In order to use the data taken under static posture for design of equipment in dynamic conditions, a guideline has been provided (Kroemer, 1983). In order to illustrate the use of anthropometric data, three examples relating to the design of handle of a sickle, wheel hand hoe and size of octagonal tubular maize sheller for female workers are given below.

According to classification of Pheasant (1998), the Indian female farm workers are between short and long legged (RSH ratio of 0.5117). Liu et al. (1999) observed that differences in anthropometric characteristics existed between different populations. Similar view was expressed for four ethnic groups, namely Chinese, Japanese, Korean and Taiwanese (Lin et al., 2004). It indicates that morphological characteristics among the four groups of people in East Asia are dissimilar. Further, ethnic differences in body shape are also affected by heredity, economic development, social environment, type of work and labour structure (Lin et al., 2004). It is clear from Table 3 that anthropometric dimensions also differed among Indian and western countries. These results suggested that it is essential to incorporate accurate anthropometry in the design process. Most of the agricultural tools/ machinery used in India are based on body dimensions of western workers. Designs that once suited the British population are followed in India (Chakrabarti, 1997). This implies that available hand tools and implements designed abroad should be modified as per local population anthropometric dimensions before introducing in their region.

Size of handle for hand tools Design of a handle depends on many factors like mode of operation, anthropometric data of user population, material of handle and shape of handle. Sickle is commonly used

Table 3. Comparison of anthropometric and strength data for Indian and western male workers S. No Body dimension

Indian data

Western data

Kashmir region

Indian (Gite and Yadav, 1989)

American (NASA, 1978)

Swedes (NASA, 1978)

USA (Helander, 1996)

1

Weight

60.0

49.3

74.9

71.6

NA

2

Stature

165.7

162.0

173.2

174.1

173.6

3

Chest circumference

86.0

83.1

99.2

NA

NA

4

Sitting height

83.8

83.8

90.5

NA

90.6

5

Popliteal height (sitting)

42.0

41.6

44.0

NA

44.2

6

Buttock popliteal length

43.7

46.6

49.4

48.2

49.5

7

Hip breadth (sitting)

31.6

30.8

35.4

NA

35.4

8

Muscular strength (elbow flexion) N

241.0

173.2

270.7

NA

NA

9

Hand grip strength, N

301.8

357.0

398.0

NA

NA

10.

RSH

0.5057

0.5172

0.5225

-

0.5218

Unit: cm unless otherwise stated; NA: Not Available 12

JAE : 49 (2)


the cob specification. Based on studies, the average size of maize cob was found to range between 30 and 42 mm. Hence, the internal diameter of fins should be in taper from 30 to 42 mm. For internal diameter (42 mm) of fins, the recommended external diameter of maize cob sheller is 50 mm. The recommended dimensions of the octagonal tubular maize sheller are presented in Table 5.

for harvesting of cereal crops in the region. The length and diameter of handle of sickle used in the region was observed to be 125 mm and 34 mm, respectively. Anthropometrically, the diameter of handle should be such that while an operator grips the handle, his longest finger should not touch the palm and also it should not exceed the internal grip diameter. The 5th percentile values of grip diameter (inside) of female farm workers was found to be 33 mm. Based on the studies of men and women with reference to an ergonomic evaluation of different hand tools with household appliances, it had been found that to allow good grip on the handle, the diameter of the handle should be a little lesser than the inside grip diameter (Nag et al., 1988). Thus, the recommended diameter of handle is 30 mm. The optimum value for grip length should be such that the widest palm should accommodate the handle. The 95th percentile value of hand breadth across thumb was 107 mm for female. The recommended length of handle for female worker works out to 117 mm allowing a clearance of 5 mm on each side of the grip. The recommended dimensions of the sickle handle are presented in Table 4.

Table 5. Modified dimensions of octagonal maize sheller

Available dimension

Diameter of handle, mm

34

30

125

118

Proposed dimension

Length, mm

70

90

External diameter, mm

61

50

Inlet, mm

32

30

Outlet, mm

42

42

Size of handle of wheel hand hoe Manual wheel hand hoe is commonly used for weeding and interculture in upland row crops. Weeds cutting and uprooting are done by the blade through push and pull action of the unit. The farmer grasps the handle and operates it in push-pull mode. Handle width, handle diameter and handle length are three important components of wheel hand hoe to be considered for ergonomic design. For maximum work efficiency, hand positioning should be such that both are close to their neutral position. Thus, handle width depends on elbow-elbow breadth. The 95th percentile values for elbow-elbow breadth were found to be 381 mm for female workers. Taking a clearance of 10 mm on each side, the recommended handle width is 401 mm. The handle of wheel hoe should be designed such that during operation the operator stands erect as far as possible to reduce musculoskeletal discomfort. For maximum work efficiency, it was suggested that the elbow flexion angle should be in the range of 85-110° (Grandjean, 1988). Tewari (1985) showed that for push and pull operation of a machine, the elbow flexion angle should be about 90 degrees. A value in the range of 50-60° has been suggested for the angle between ground and handle (Pradhan et al., 1987; Philip and Tewari, 2000). Elbow flexion angle as 100°; angle of operation as 45°; 5th and 95th percentile value of elbow height as 875 and 1086 mm, respectively; and elbow grip length for 5th and 95th percentile population as 294 and 373 mm, respectively (Tewari et al., 2007) were considered for determining the optimum length of handle. For female population under study, the recommended handle length ranged between 1038.7- 1203.5 mm. The recommended dimensions of a wheel hoe are given in Table 6.

Proposed dimension

Length of handle, mm

Available dimension

Diameter of fins, mm

Table 4. Modified dimensions of sickle handle Parameter

Parameter

Size of octagonal maize sheller The marginal and small farmers of hilly region extensively use octagonal hand operated maize sheller for maize shelling, generally performed by women. The sheller is held in one hand, a cob held in other hand (preferable hand) is inserted into it with forward and backward twist to achieve shelling. The sheller is held such that finger and thumb make a grip around the sheller. The length and external diameter of sheller used in the region (CIAE design) was 70 and 61 mm, respectively. The diameter of fins is in taper from 32 to 42 mm (inlet to outlet). Based on anthropometric consideration, the external diameter of sheller should not exceed the grip span of user (say female). The external diameter of sheller should be 5th percentile value of grip span to accommodate the larger population group, which in this case was 44 mm for female workers. For efficient work, the length of sheller should accommodate the maximum dimension of hand breadth at metacarpal-III. The 95th percentile value of the above dimension for female was 90 mm. Thus, the recommended length of maize sheller is 90 mm. The internal diameter of fins should be as per 13

April - June, 2012

Anthropometry of Farm Workers of Kashmir Region of India for Equipment Design

Gite LP; Chatterjee D. 1999. All India anthropometric survey of agricultural workers: proposed action plan. All India Coordinated Research Project on Human Engineering and Safety in Agriculture, Central Institute of Agricultural Engineering, Bhopal, India.

Table 6. Modified dimensions of wheel hand hoe Parameter

Available dimension

Proposed dimension

Length of handle, mm

1400

1035.7- 1203.5

Width of handle, mm

550

401

Diameter of handle, mm

46

43

Gite LP. 1999. Optimum handle height for animal drawn mouldboard plough. Appl. Ergon., 22(1), 21-28. Gite LP; Tiwari PS; Babu VB. 2005. Anthropometric and strength survey of agricultural workers of Madhya Pradesh. Annual progress report AICRP on Ergonomics and safety in Agriculture, CIAE, Bhopal.

CONCLUSIONS 1. Kashmiri women are taller than southern, central and western Indian women by 31, 26 and 28 mm, respectively. Same trend was observed for the data on body circumferences and breadth dimensions. However, most of their body dimensions are comparable to those of North-eastern Indian women.

Grandjean E. 1988. Fitting the Task to the Man. Taylor and Francis, London. Helander Martin.1996. A Guide to the Ergonomics of Manufacturing. Taylor and Francis, London.

2. Indian male workers are shorter in stature by 84 mm than Swedes male workers and 132 mm shorter in chest circumference than American workers. They are shorter in buttock popliteal length by 57 mm than Americans.

Hertzberg HTE. 1968. The conference on standardization of anthropometric techniques and terminology. Am. J. Phys. Anthropol., 28(1), 1–16.

3. Muscular strength of Indian male workers (241 N) is lower than that of American workers (271 N). Similarly hand grip strength of Indian male workers (301.8 N) is lower than that of American workers (398 N).

ISO 7250. 1996. Basic Human Body Measurements for Technological Design. International Standard Organization, Genava. Kathervel K; Sivakumar SS; Ramesh D. 2005. Collection of anthropometric and strength data of male and female agricultural workers of Tamil Naidu. Project Report, All India Coordinated Research Project on Human Engineering and Safety in Agriculture, TNAU Coimbatore Centre.

4. The RSH of Indian male workers is 0.5057 against 0.5225 of American workers. 5. Data generated would be useful for the designers to develop and introduce machines suiting to the requirements of population so that human drudgery in operation could be minimised and operator’s comfort could be enhanced.

Kroemer KHE. 1983. Engineering anthropometry: work, space and equipment to fit the user. In: Oborne D; Gruneberg M (Eds.), The Physical Environment at Work, Wisley, London.

ACKNOWLEDGEMENT The authors are thankful to the Indian Council of Agricultural Research (ICAR), New Delhi for funding the project.

Lin YC; Wang MJ; Wang EM. 2004. The comparisons of anthropometric characteristics among four people in East Asia. Appl. Ergon., 35, 173-178.

REFERENCES

Liu WCV; Sanchez-Monroy D; Parga G. 1999. Anthropometry of female aquiladora workers. Int. J. Ind. Ergon., 24, 273–280.

Chakrabarti D. 1997. Indian anthropometric dimensions for ergonomic design practice. National Institute of Design, Ahmedabad, India.

NASA. 1978. Anthropometry for designer. In: Anthropometric Source Book, vol. I, NASA Reference Publication 1024, National Aeronautics and Space Administration, Washington.

Dewangan K N; Owary C; Datta RK. 2008. Anthropometric data of female farm workers from north eastern India and design of hand tools of the hilly region. Int. J. Ind. Ergon., 38, 90-100.

Nag PK; Goswami A; Ashtekar SP; Pradhan CK. 1988. Ergonomics in sickle operation. Appl. Ergon., 19(3), 233239.

Gite LP; Yadav BG. 1989. Anthropometric survey for agricultural machinery design. Appl. Ergon., 20(3), 191-196.

14

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Pheasant S. 1998. Bodyspace: Anthropometry, Ergonomics and the Design of Work. Second ed., Taylor & Francis, London.

Ergonomics in Developing Countries, Jakharta, Indonesia.

Philip GS; Tewari VK. 2000. Anthropometry of Indian female agricultural workers and implication on tool design. Agric. Mechanization in Asia, Africa and Latin America, 31(1), 63-66.

Tewari VK. 1985. Development of weeder from engineering and ergonomic considerations. Unpublished PhD Thesis, Department of Agricultural and food Engineering, Indian Institute of Technology, Kharagpur, India.

Power AG; Aware VV. 2005. Anthropometric survey on agricultural workers of Konkan region of Maharashtra state for efficient and safe design of agricultural equipment. Annual Project Report, ICAR funded project.

Tewari VK; Ailavadi R; Dewangan KN; Sharangi S. 2007. Rationalized database of Indian agricultural workers for equipment design. Agric. Eng. Int., The CIGR Ejournal, Manuscript MES 05 004, IX.

Pradhan CK; Goswami A; Gosh SN; Nag PK. 1987. Ergonomic design and physical evaluation of spade work. In: Proceedings of the International Symposium on

Wang EM; Wang M; Yeh W; Shih Y; Lin Y. 1999. Development of anthropometric work environment for Taiwanese workers. Int. J. Ind. Ergon., 23, 3-8.

15


Mathematical Model for Shelf-life of Chickpea Sprouts under Modified Atmospheric Packaging Ranjeet Singh1, Ashok Kumar2 , Jarnail Singh3 and S. D. Kulkarni4 Manuscript received: April, 2011

Revised manuscript accepted: May, 2012

ABSTRACT Simulation study compared predicted in-pack gaseous composition of O2 and CO2 with the actual experimental data and predicted in-pack water vapour and temperature as well as the appropriate shelf life of chickpea sprouts. The actual and simulated results for in-pack gaseous composition O2/CO2 was 14.46; 8.45 % and 14.99; 7.92 % for PP package (100g) and 14.22; 8.85 % and 14.21; 10.57 % for 100g of LDPE package containing chickpea sprout under MAP. Verification of developed model considered the prediction of in-pack gaseous composition and storage period packed under PP and LDPE polymeric films with the experimental value and showed a near proximity. A model with the selected quality attribute (lightness of hypocotyl) thus could provide a fair insight into the shelf life of chickpea sprout under modified atmospheric packaging. Key words: Chickpea (Cicer arietinum) sprouts, MAP, respiration rate, modelling, shelf life

A short shelf life of products like fresh vegetables and fruits is a major problem to producers. Producers have been striving for an acceptable way of extending the shelf life at reduced cost. One of the widely applied techniques is modified atmosphere packaging (MAP) together with cold storage condition. Even though MAP method has been known for a long time, the technique has a limited use in certain groups of vegetables or fruits due to lack of allpurpose packaging film and also of accuracy of plant respiration and transpiration predictive models (Susana et al., 2002). The latter issue is a big hurdle since the models need to incorporate a function of storage variables, e.g. humidity, temperature and air composition. Currently, there are only three respiration models used for MAP design, namely constant rate respiration model, enzyme kinetic model, and transition state model (Emond et al., 1991; Lee et al.,1991; Fonseca et al., 2002; Rai et al., 2002; Iqbal et al., 2009). The only model that is a true function of temperature was the transition state model, whereas the other two models rely on Arrhenius function to predict the effect of temperature on respiration rate. Nevertheless, all the three models require a specific group of parameters based on actual measurement of plant respiration (Liu and Li, 2004). The other important aspect is related to the designing of MAP for the products, for which the process involves lot of computation. The computation must simultaneously consider all factors, i.e. plant respiration, packaging constraints and storage conditions. Since each

of the factors contain many data and variables, the computational protocol to predict the shelf life frequently becomes a cumbersome process. Perhaps this may be the main reason for a slow improvement on the MAP technology (Del and Romani, 2006; Toshitaka and Daisuke, 2004). The development of a mathematical model capable of accurately predicting the shelf life of chickpea sprouts was, therefore, attempted. The paper demonstrates simulation and validation of developed model for shelf life prediction of chickpea sprouts under modified atmospheric packaging. MATERIALS AND METHODS Mathematical Modelling for Storage of Chickpea Sprouts under MAP Development of component equations consisted of identification of model parameters based upon the conceptualization of modified atmospheric packaging of chickpea sprouts. The parameters in terms of the variables/characteristics related by different components of MAP system i.e produce; packaging film, package and environment were identified for model development. These parameters were defined as respiration rate and transpiration co-efficient of the produce; thickness and permeability of polymeric film; area, size, and effective permeability of perforations, void

Scientist (SS), APPD, Central Institute of Agricultural Engineering, Nabi-Bagh, Berasia Road, Bhopal-462038, e-mail: [email protected]; Professor –cum- Head, 3 Professor, Department of Processing & Food Engineering, Punjab Agricultural University, Ludhiana-141004; 4 Project Director, APPD, Central Institute of Agricultural Engineering, Nabi-Bagh, Berasia Road, Bhopal-462038 1 2

JAE : 49 (2)

Ranjeet Singh, Ashok Kumar , Jarnail Singh and S. D. Kulkarni

volume of package; and temperature and relative humidity of environment. The various components of MAP were identified along with the input; output and parameters based upon these relationships/equations. The fundamental concepts involved in consumption and evolution of gases within the MA package and transfer of various gases through the package surface led to the development of mathematical relationships between inputs, outputs and other parameter of the system.

(Paul and Clarke, 2002):

Ji

Ji

Where, J is the diffusion flux of a gas, mol.m-2.h-1; D is the diffusion coefficient, m2.h-1; is the concentration, mol.m-3 and x is the thickness of film, mm.

J CO2

J O2 =

J CO2 =

in

(2)

Tp PCO2 × A p × ( p CO2

out

(3)

J H 2O

Similarly, the diffusive flow rate of water vapour across the film package in terms of film and environmental parameters is described by equation 4 (Talasila and Cameron, 1997):

J H 2O =

Tp

out

out

in

− p O2 )

(6)

= RO2 × M

MBS

(7)

= RCO2 × M

.

(8)

in

− p CO2 )

Tp

PH 2O × A p × ( p H 2O

(5)

The amount of the water vapour transpired from the surface of packaged produce during a particular interval of time MBS J H 2O (ml.h-1 ) is described as a product of transpiration coefficient K (ml.kg-1.h-1.kPa-1), initial mass of the sample, M (kg), the difference in saturated vapour pressure at sat produce surface p H 2O (kPa) and partial pressure of water in vapour inside film package/container p H 2O (kPa), and calculated by the Equation 9 (Talasila and Cameron, 1997; Salvador et al., 2002):

concentration of gases inside (P in) and outside (P out) the package by following relationships (Cameron et al., 1989; Salvador et al., 2002; Zhu et al., 2002):

− p O2 )

= n p .D i ( p O2

MBS

) through which gas φA p

exchange occurs, thickness ( T p ), and difference in

out

per

J O2

The rate of diffusion of O2 and CO2 across a permeable film package is described in terms of film characteristics

PO2 × A p × ( p O2

in

− p O2 )

The packaged sample respires and keeps on consuming the in-pack O2. Simultaneously, evolution of CO2 and water vapour takes place. The total quantity of O2 consumed MBS MBS J O2 (ml.h-1) and CO 2 produced J CO2 (ml.h -1) during a particular interval of time by a certain quantity of produce under MAP in a film package is defined as the product of respiration rate RO2 or RCO2 (ml.kg-1.h-1) and mass of the sample M (kg) expressed through relationships (Eq. 7 and 8), given by Beaudry et al., 1992 and Zhu et al., 2002:

(1)

(gaseous permeability (P), area (

out

For number of perforations (np)

Fick’s law of diffusion states that the steady state mass transfer of a gas through a unit area of a film of known thickness is proportional to concentration gradient, and represented by the following relationship:

∂φ ∂x

= D i ( p O2

Where, D is the diameter of perforation, mm.

Respiration rate and in-pack prediction of gases

J = −D

per

= K × M × ( p H 2O

sat

in

− p H 2O )

(9)

The concentration of water vapour during storage under MAP depends upon the transpiration of the produce as well as water vapour diffusion across the package surface. If water vapour permeability of the film decreases during storage due to formation of a thin water film on inside surface of the package, water vapour will condense in the form of droplets inside the film package.

in

− p H 2O )

MBS

(4)

Thus, the in-pack concentration of different gaseous components in a polymeric film package can be predicted by carrying out a simple mass balance on produce-package

The gaseous and water vapour exchanges through macroperforations can be described by the following relationship 17

April - June, 2012

Mathematical Model for Shelf-life of Chickpea Sprouts under Modified Atmospheric Packaging

system and combining the equations 2 to 9. This would result in the following ordinary differential Equations (Hayakawa et al., 1975; Talasila and Cameron, 1997; Techavises and Hikida, 2008; Susanna et al., 2002): dp O2

in

dt

dp CO 2

in

dt

dpH 2O

⎡⎛ pO × A p = ⎢⎜ n p DO2 + 2 ⎜ Tp ⎢⎣⎝

⎤ ⎞ ⎟ p O out − p O in − RO . M ⎥ pt 2 2 ⎟ 2 ⎥⎦ V ⎠

(10)

⎡⎛ p CO 2 × A p = ⎢⎜ n p D CO 2 + ⎜ Tp ⎣⎢⎝

⎤ ⎞ ⎟ p CO out − p CO in − RCO . M ⎥ p t 2 2 2 ⎟ ⎠ ⎦⎥ V

(11)

in

dt

(

(

)

(

)

provided as input (constants) in the transient-state model equations (Eq. 10, 11 and 12), and these equations were solved using computer source code written in Microsoft Visual C# .net language. The solution of the equations could predict the transient-state partial pressure of O2 and CO2 inside the film packages containing a known weight of chickpea sprout stored under MAP at a particular temperature and R.H as also the respiration rates (O2 consumption and CO2 evolution). During storage, the brightly coloured sprout undergoes deterioration. This change in colour can act as an analysis parameter to judge the freshness and quality of sprouted chickpea in storage. The intensity of colour is represented by its lightness (L), which is measured by colourimeter (McGuiree, 1992). The predicted environmental condition from the equations 10, 11 and 12 was combined with the period of storage and the consequent quality (lightness) on the stored hypocotyl of sprouted chickpea to arrive at a generalized relationship to predict safe storage.

⎡⎛ p H O × Ap ⎞ ⎟ p H O out − p H O in + = ⎢⎜ n p DH 2O + 2 2 ⎜ ⎟ 2 Tp ⎢⎣⎝ ⎠

+ K.M pH 2O

(

sat

⎤p in − pH 2O ⎥ t ⎦⎥ V

)

)

(12)

The equations 10, 11 and 12 would predict the concentrations of different gaseous constituents at any point of time for the specified parameters of produce and package during the entire storage period.

Development of computer codes for prediction of inpack transient state parameters The developed programme required input on fresh produce, film, package, and initial gaseous and environmental parameters (Fig. 1 and 2). The programme received the inputs and intermediate transient state parameters such as respiration rates. These values were further used to get the final results and arrive at in-pack partial pressures during the entire storage period at any time. The programme evaluated L-value of hypocotyl (lightness) for the specified

Numerical solution The transient-state model equations (Eq. 10, 11 and 12) were solved numerically (Rao and Shantha, 1992) for solutions of the ordinary differential equation. The values of various parameters related to produce, package, determined independently at various temperatures, were

Fig. 1: Input portion of flow chart 18

JAE : 49 (2)


Fig. 2: Output portion of flow chart

input variables corresponding to the consumer acceptable parameters.

atmosphere (or environmental) comprised of normal air, the outside partial pressure for O2, CO2 and H2O were also taken as 21.16 and 0.03 %, respectively. The step-size for the time interval selected for the simulation studies was taken as one hour for the entire storage period.

Model simulation In the present study, the in-pack atmosphere for polymeric film packages containing fresh chickpea sprouts was simulated using the developed computer programme. The transpiration and respiration rate parameters and the mass of chickpea sprout were taken as the produce parameters. The thickness and the permeability coefficients for O2 and CO2 were used as film parameter. The total surface area of the package, void volume of the packages, number and size of perforations and effective permeability of perforation for O2 and CO2 constituted the inputs for package parameter at the selected temperature (10oC), and 75 % relative humidity (Table 1). The initial in-pack and the partial pressure of the different gases were taken as the input for initial environmental conditions. Initially, the package headspace contained air, so initial in-pack partial pressure for O2 and CO2 were taken as 21.6 and 0.03 %, respectively (Talasila and Cameron, 1997). Similarly, as the storage

Simulation conditions The initial conditions for the simulation were set as follows: concentration of O 2 inside the bag= 21.6±0.1 %, concentration of CO2 inside the bag = 0.03±0.1 %, relative humidity of air = 75%, storage temperature= 10oC, and heat transfer coefficient of the air inside and outside the package = 1 W.m-1.K-1. Model validation The predicted value of in-pack gaseous composition of O2 and CO2, at any point of time, obtained from the computer implementation of the numerical solutions of equation 10, 11 and 12 were compared with the subjective (AOAC, 1965) and objective (Rangana, 1986) experimental data, 19

April - June, 2012


Table 1. Input package parameters Parameter

Value

Package length, m

0.182

Package breadth, m

0.131

Area of package, m2

0.046

Void volume, ml

100g: 823.12; 150g: 893.52; 200g: 964.04

Thickness of PP & LDPE polymeric film, μm

2.54

No of perforations

06

Diameter of perforations, mm

0.30

Effective permeability of perforation, ml.h-1.kP-1

0.986

Physiological loss in mass (PLM)

from actual storage under MAP in different film packages. The determined parameters were correlated with the predicted value of in-pack gaseous composition and subsequently with the shelf life of chickpea sprouts under MAP corresponding to the limiting value of the lightness of hypocotyl of chickpea sprouts (L=43). The different grades of chickpea sprouts based on the lightness of hypocotyl (L≥43) would qualify as wholesome and well flavoured produce from the point of view of consumer.

Physiological loss in mass was determined by weighing all samples with a laboratory level weighing scale (Model CX 504, Scaltec Instruments GmbH, Germany) having least count ±0.001g, at the beginning and end of the storage period. The difference between the two values was considered as mass loss and expressed in per cent.

PLM (%) =

Initial mass − Final mass × 100 Initial mass for storage of chickpea sprouts under MAP

...(13)

Experimental Procedure

Package headspace gas concentration

Plant material

The headspace gas concentration of O2 and CO2 were analyzed using a portable headspace gas analyzer (Model 902 D Dualtrak, Quantek). The apparatus uses an electrochemical and an infrared sensor to evaluate the headspace gas concentration and express it in percent. The sensor probe was inserted in the headspace of polymeric package and sensor signals were converted to gas concentration values of O2 and CO2, which were directly read on the digital display panel.

Chickpea (Cicer arietinum L.) sample of variety PBG-5 at full maturity was collected from a local farm in autumn. Chickpea seed were carefully inspected, any soil residues removed from grain surface, uniformly treated with Calcium Hypo-chloride [Ca (OCl)2]@ 20,000 ppm for 15 min for sterilization, and then soaked in clean water (1: 3, w/v) for 12 h (overnight) at ambient room temperature. In the next morning, the water was drained and the soaked seed were rinsed with clean fresh water before being shifted to clean sterile muslin cloth and placed in dark at ambient temperature of 26±4 oC for sprout growth. After 36 h, the sprouts were taken for experimentation.

pH analysis To measure pH, sprouted chickpea mixture was prepared as described by Barry-Ryan et al. (2000) using 1:1 of product and distilled water. Ten grams of chickpea sprout mixture were blended for 2 min with 10 ml of distilled water (pH: 7). Observations on pH of the prepared mixture were then taken using a portable pH meter (H160G portable pH meter). The pH of freshly harvested sprouts was measured before packaging and later on each day of storage with three replications.

Storage condition Sprouted samples were stored in modified atmosphere at 10±1oC and 75% RH, using a walk-in-type cool chamber, and analyzed every day until the end of the storage period of 7 days. Unpacked chickpea sprout sample stored at 10±1oC and 75% RH was used as control.

20

JAE : 49 (2)


and carbon dioxide evolution stabilized around 99.94ml.kg-1.h-1 and 66.52 ml.kg-1.h-1, respectively. Similar trends of rate of oxygen consumption and carbon dioxide evolution were observed in PP package with 150g of mass. Package with 200g stabilized at around 66.30; 65.19 ml.kg-1.h-1 and 98.83 and 97.72 ml.kg-1.h-1, respectively.

Hypocotyl colour Hypocotyl surface colour was measured at termination of sprouting and during storage using a handle colourimeter (chromameter) (Miniscan XE plus, Hunter associates, USA) appropriately calibrated with a standard white tile (UE certificated) with the following parameters: X=83.47, Y=84.43, Z=95.16 with illuminant C/2o, according to CIE L*, a*, b* scale. Data were collected for the hypocotyls and reported as an average of 30 measurements.

Likewise, Fig 3b shows that in-pack O2 depleted at a relatively faster rate leading to decline in oxygen consumption rate within a short span of time in LDPE package with 100g mass. During initial 24 h, the rate of oxygen consumption and carbon dioxide evolution stabilized at 96.72 ml.kg -1.h -1 and 63.52 ml.kg -1.h -1, respectively. Similar trends of rate of oxygen consumption and carbon dioxide evolution were observed in PP package having 150g, while 200g package rate stabilized at around 95.95 and 94.95 ml.kg-1.h-1 for O2 and 63.31 and 61.50 ml.kg-1.h-1 for CO2, respectively.

Yeast and mould counts Twenty-five g of each sample were aseptically placed into a sterile stomacher bag with an appropriate amount of buffered peptone water (Difco, Detroit, Mich., U.S.A.) to achieve a 10-1 dilution and pummelled for 2 min in a Tecmar 400 Stomacher (Tecmar® Co., Cincinnati, Ohio, U.S.A.). Serial dilutions were made in 0.1% buffered peptone water. Total yeast and moulds were enumerated (Soylemez, 2001).

The trends of both the curves became asymptotic, as evident from the straight-line portion in Fig 3a and 3b. However, steady state was established after sometime when both these rates matched. Thus, attaining equilibrium at a faster rate

Overall acceptability Visual quality evaluation was carried out for overall acceptance using a 10 point hedonic scale with the help of a test panel consisting of five panelists of different age groups and having different eating habits. The sprouted chickpea was served raw and the average indices (A.I.) of all the panelists were computed for different samples (Ranganna, 1986): A. I =

Total Scores No. of evaluators

Predicted CO2 Respiration rate, ml.kg-1.h-1

Predicted O2

… (14)

Statistical Analysis The entire set of experiment was replicated thrice. Analysis of variance (ANOVA), coefficient of determination (R2) and standard error for both objective and subjective parameters were carried out using SPSS 14.0 software. The developed model was analyzed using GraphPad PRISM® Version 5.00.288 software (GraphPad Software, Inc.).

(a) Predicted O2 Respiration rate, ml.kg-1.h-1

Predicted CO2

RESULTS AND DISCUSSION Rate of Respiration Output of the model component computed the in-pack gaseous composition for any specified time interval. The actual experimental observations of in-pack gaseous compositions were compared with model simulated values for validation. Fig 3a depicts that in-pack O2 depleted at a faster rate leading to decline in oxygen consumption rate within a short span of time in PP package having 100g mass. During initial 24 h, the rate of oxygen consumption

Fig. 3:

21

Simulated results for respiration rate in (a) PP and (b) LDPE polymeric packages (200g) under MAP for a storage period of 7 days

April - June, 2012


is highly desirable, and requires appropriate matching of permeability through film and perforations with the rates of respiration of the produce.

first day of storage. This indicated that the atmospheric modulation established immediately as the experimental packages were placed under designd MAP. The computer generated model predicted results, obtained through simulation for a particular set of variables, were in close agreement with experimental observations under the specified conditions (Fig 5).

In-pack Gaseous Compositions The in-pack O2 composition in PP package, remained well above the lower limit throughout the storage period of 7 days for all the treatments (Fig.4, Table 2). The headspace gaseous composition, steady state condition of 14.99 and 7.92 % (Table 3) was achieved in 24 h of storage in PP package having 100g mass. Following similar trend, 150g and 200g pack containing fresh chickpea sprouts, gas compositions were 15.77 and 9.99 %; 13.28 and 13.41 %, respectively. O2 concentrations decreased sharply with increase in package mass, but did not differ much after

Similarly, it was observed that under steady-state condition, the simulated results for gaseous composition O2 and CO2 having mass of 100g was 14.21 and 10.57 %, respectively (Fig 6). Similar pattern of experimental results for O2 and CO2 in-pack gas concentrations for LDPE (150g and 200g) containing fresh chickpea sprouts during the first 24 h of storage were obtained as 12.09 % and 13.71 %; 10.10 %

Table 2. Headspace (HS) of experimental gaseous composition (%) in chickpea sprouts sample

0.03±0.1 9.13±0.1 9.27±0.1 8.52±0.1 8.34±0.1 8.52±0.1 8.49±0.1 8.45±0.1

100g; O2 21.6±0.1 20.14±0.1 19.12±0.1 18.82±0.1 17.71±0.1 16.92±0.1 16.94±0.1 16.33±0.1 100g; CO2 0.03±0.1 9.16±0.1 8.87±0.1 8.62±0.1 8.59±0.1 8.42±0.1 8.40±0.1 8.39±0.1

21.6±0.1

100g; O2 21.6±0.1

21.6±0.1 17.23±0.1 15.14±0.1 14.92±0.1 15.03±0.1 14.85±0.1 14.76±0.1 14.46±0.1

15.23±0.1 15.12±0.1 15.09±0.1 14.73±0.1 14.63±0.1 14.25±0.1 14.22±0.1 0.03±0.1 9.75±0.1 9.52±0.1 9.36±0.1 9.12±0.1 8.98±0.1 8.82±0.1 8.85±0.1

15.23±0.1 14.22±0.1 14.38±0.1 14.28±0.1 14.27±0.1 14.38±0.1 14.4±0.1 100g; CO2 0.03±0.1 10.09±0.1 10.64±0.1 10.72±0.1 10.82±0.1 10.14±0.1 10.34±0.1 10.74±0.1

21.6±0.1 19.20±0.1 18.73±0.1 18.42±0.1 17.78±0.1 17.01±0.1 16.42±0.1 16.12±0.1 0.03±0.1 9.66±0.1 9.41±0.1 9.12±0.1 9.01±0.1 8.94±0.1 8.93±0.1 8.94±0.1

21.6±0.1 15.42±0.1 14.72±0.1 14.52±0.1 13.72±0.1 13.92±0.1 14.02±0.1 13.99±0.1 0.03±0.1 10.42±0.1 10.92±0.1 11.01±0.1 10.82±0.1 10.52±0.1 11.72±0.1 12.12±0.1

HS gas composition in chickpea sprouts sample packed in PP (10oC) Av. 150g; O2 Av. 21.60±0.1 21.6±0.1 21.6±0.1 21.6±0.1 21.6±0.1 21.6±0.1 18.86±0.1 16.79±0.1 17.52±0.1 18.22±0.1 17.51±0.1 15.19±0.1 17.67±0.1 15.23±0.1 16.98±0.1 16.88±0.1 16.36±0.1 13.42±0.1 17.38±0.1 14.52±0.1 14.78±0.1 15.76±0.1 15.02±0.1 12.29±0.1 16.84±0.1 13.91±0.1 14.71±0.1 16.43±0.1 15.01±0.1 12.66±0.1 16.26±0.1 13.81±0.1 14.62±0.1 15.98±0.1 14.80±0.1 12.79±0.1 16.04±0.1 13.69±0.1 14.53±0.1 15.89±0.1 14.70±0.1 12.52±0.1 15.63±0.1 13.47±0.1 14.39±0.1 15.51±0.1 14.45±0.1 12.31±0.1 Av. 150g; CO2 Av. 0.03±0.1 0.03±0.1 0.03±0.1 0.03±0.1 0.03±0.1 0.03±0.1 9.32±0.1 11.12±0.1 11.01±0.1 11.92±0.1 11.35±0.1 15.42±0.1 9.18±0.1 11.21±0.1 10.98±0.1 11.84±0.1 11.34±0.1 15.01±0.1 8.75±0.1 11.10±0.1 10.85±0.1 11.72±0.1 11.22±0.1 14.72±0.1 8.65±0.1 11.16±0.1 10.76±0.1 11.77±0.1 11.23±0.1 14.75±0.1 8.62±0.1 11.13±0.1 10.99±0.1 11.70±0.1 11.27±0.1 14.74±0.1 8.60±0.1 11.12±0.1 10.55±0.1 11.65±0.1 11.10±0.1 14.69±0.1 8.59±0.1 11.10±0.1 10.51±0.1 11.64±0.1 11.08±0.1 14.66±0.1 HS gas composition in chickpea sprouts sample packed in LDPE (10oC) Av. 150g; O2 Av. 21.6±0.1 21.6±0.1 21.6±0.1 21.6±0.1 21.6±0.1 21.6±0.1 15.29±0.1 14.68±0.1 14.66±0.1 14.24±0.1 14.27±0.1 14.21±0.1 14.20±0.1 Av. 0.03±0.1 10.08±0.1 10.36±0.1 10.37±0.1 10.25±0.1 09.88±0.1 10.29±0.1 10.57±0.1

13.23±0.1 12.95±0.1 12.89±0.1 12.69±0.1 12.84±0.1 12.63±0.1 12.14±0.1 0.03±0.1 14.42±0.1 14.4±0.1 13.98±0.1 13.83±0.1 13.67±0.1 13.9±0.1 13.52±0.1

14.4±0.1 13.56±0.1 13.05±0.1 13.89±0.1 13.36±0.1 13.32±0.1 13.42±0.1 150g; CO2 0.03±0.1 13.84±0.1 13.96±0.1 13.52±0.1 12.99±0.1 12.87±0.1 12.84±0.1 12.78±0.1

22

12.64±0.1 12.52±0.1 11.92±0.1 11.26±0.1 11.13±0.1 11.72±0.1 11.63±0.1 0.03±0.1 14.92±0.1 14.89±0.1 14.47±0.1 14.33±0.1 14.72±0.1 14.92±0.1 14.43±0.1

13.42±0.1 13.01±0.1 12.62±0.1 12.61±0.1 12.44±0.1 12.55±0.1 12.39±0.1 Av. 0.03±0.1 14.39±0.1 14.41±0.1 13.99±0.1 13.71±0.1 13.75±0.1 13.88±0.1 13.57±0.1

11.92±0.1 11.52±0.1 10.28±0.1 10.22±0.1 10.19±0.1 10.18±0.1 10.05±0.1 0.03±0.1 17.61±0.1 17.55±0.1 16.22±0.1 16.06±0.1 16.98±0.1 16.78±0.1 16.42±0.1

200g; O2 21.6±0.1 15.63±0.1 14.27±0.1 14.01±0.1 13.12±0.1 12.98±0.1 12.88±0.1 12.74±0.1 200g; CO2 0.03±0.1 16.39±0.1 16.12±0.1 15.76±0.1 15.65±0.1 15.37±0.1 15.26±0.1 15.19±0.1

0.03±0.1 14.71±0.1 14.62±0.1 14.34±0.1 13.98±0.1 13.53±0.1 12.98±0.1 12.73±0.1

Av. 21.6±0.1 15.08±0.1 14.31±0.1 12.94±0.1 12.71±0.1 12.63±0.1 12.45±0.1 12.15±0.1 Av. 0.03±0.1 15.50±0.1 15.25±0.1 14.24±0.1 14.79±0.1 14.54±0.1 14.31±0.1 14.19±0.1

200g; O2 21.6±0.1

21.6±0.1

Av. 21.6±0.1

11.4±0.1 11.92±0.1 10.27±0.1 10.14±0.1 10.42±0.1 10.19±0.1 10.41±0.1 200g; CO2 0.03±0.1 17.15±0.1 16.96±0.1 16.88±0.1 16.72±0.1 16.65±0.1 16.58±0.1 16.34±0.1

21.6±0.1 14.44±0.1 15.24±0.1 12.52±0.1 12.35±0.1 12.13±0.1 11.97±0.1 11.42±0.1

10.92±0.1 8.87±0.1 8.82±0.1 8.66±0.1 8.15±0.1 9.24±0.1 9.64±0.1 0.03±0.1 17.74±0.1 15.62±0.1 15.12±0.1 15.01±0.1 14.97±0.1 15.32±0.1 15.39±0.1

11.42±0.1 10.77±0.1 09.79±0.1 09.67±0.1 09.58±0.1 09.87±0.1 10.03±0.1 Av. 0.03±0.1 17.50±0.1 16.71±0.1 16.07±0.1 15.93±0.1 16.20±0.1 16.22±0.1 16.05±0.1

JAE : 49 (2)


pO2

Predicted pCO2

pCO2

Fig. 4:

Headspace gas, % (Simulated)

Headspace gas, O2/CO2

Predicted pO2

Simulated results for gas composition of O2/CO2 for chickpea sprout in PP package (200g) under MAP for a storage period upto 7 days

Headspace gas composition, % (Actual)

Actual and simulated values are non-significant at 5% level of significance (P