Advanced Materials Research Vols. 347-353 (2012) pp 1647-1651 Online available since 2011/Oct/07 at www.scientific.net © (2012) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.347-353.1647
Research on Chemical Composition and Ensiling Characteristics of Banana Stems and Leaves Jinsong Yang1a , Haisheng Tan1b, Hairui Zhai1c, Qian Wang1d, Nan Zhao1e, Yimin Cai2f, Mao Li3g, Hanlin Zhou3h* 1 Hainan University, Haikou, Hainan 570228, China 2 Japan International Research Center for Agricultural Sciences 3 Chinese Academy of Tropic Agriculture Sciences, Hainan 571737, China a
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[email protected], *Hanlin Zhou: Corresponding author, Email:
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Keywords： ：banana stems and leaves, silage, fermentation quality.
In order to investigate the nutritive and ensiling characteristics of banana stems and leaves, the chemical compositions of banana stems and leaves were analyzed and the effects of additives on fermentation quality were measured. The research results showed: Banana stems and leaves had high fiber content (stem>58% DM, leaf >72% DM), nitrogen free extract content (>50% DM), and water soluble carbohydrate contents (WSC>5% DM), with certain nutritive value. Tannins of banana stem and leaf were 0.11% DM and 0.24% DM. There were lactic acid bacteria (>105cfu/g FM) in the banana stems and leaves; they might be well preserved with some treatments. Abstract.
Introduction Banana (or Musa paradisiacal) was one kind of popular tropical fruit. The growth area in china increased 5%～10% in 2010 to about 5.30 million acres with a total output of 8.50 tons. At the mean time of producing big amount of it, banana stems and leaves of about the same quantity were also produced and abandoned as waste in a long term; hence, it became an important topic about how to dispose of them [1]. There are certain content of protein, crude fat, and crude fiber in banana stems and leaves which made it a very potential non-convention plant feed [2]. There was a big amount of tannin in banana stem and leaf. The combination of tannin and glycoprotein, which was used in oral lubrication, was insoluble and tasted bitter leading to fewer feed intake [3]. Another factor causing banana stem and leaf bad taste and low digestibility was huge amount of fiber contained. Thus, it would help to make full of banana stem and leaf by improve the fiber’s nutritive value and remove or inactivate tannin. There were many methods to processing banana stem and leaf, and in comparative to others, ensiling was relatively low cost one. The energy and protein digestibility of silage was higher than dryer one; in addition, content of digestible crude protein, total nutrient and energy content in dry matter of silage were also high. What’s more, digestibility of silage’s cell wall after silage fermentation was apparently increased [4]. In order to use the by-products as feeds for dairy cows well, the chemical compositions of banana stem leaf were analyzed and the effects of wilting and additives on their fermentation quality were measured.
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Materials and Methods Silage preparation. Banana stems and leaves were obtained from Banana plantations in Hainan province, China. The materials were chopped to approximately 2cm, wilting and were ensiled directly or after treated with 5% molasses (II group), 1% lactic acid bacteria (LAB, Lactobacillus plantarum HN1) inoculation at 1.0×108 cfu/g FM (III group), 5% molasses +1% LAB (IV group). The control (I group) was made without additives. Each 200g treated material was packed into a plastic film bag and the bags were degassed, sealed and kept at ambient temperature for 40 days. Chemical analysis. Dry matter (DM) content was determined by oven drying at 70˚C for 48 h. Crude ash content was measured after incinerated for 3 h at 550˚C. Crude protein (CP) and ether extract were analyzed according to AOAC methods [5]. Water soluble carbohydrate (WSC) content was determined using the anthrone method [6]. The buffering capacity was determined as described by Playne and McDonald [7]. Tannin content was determined by the use of Phosphor molybdatetungstic acid colorimetric method [8] Microbial analysis. Ten gram of material was shaken well with 90mL of sterilized saline solution (0.85% NaCl), and serial dilutions (10-1-10-6) were made in sterile saline solution. LAB was counted on MRS medium agar (Difco Laboratories, Detroit, Mich, USA.) after incubation in an anaerobic incubator (N2:H2:CO2 =85:5:10, YQX-II, CIMO Medical Instrument Manufacturing Co., Ltd, Shanghai, China) at 37˚C for 2 days. Yeasts and molds were counted on potato dextrose agar (Nissui-seiyaku Ltd, Tokyo, Japan) acidified with sterilized tartaric acid solution (10%) to pH 3.5. These agar plates were incubated at 37˚C for 2 days. Fermentation quality. When the bag silos were opened, 20g of silage sample was taken and mixed with 80mL of distilled water and stored in a refrigerator at 4˚C for 18 h. Then, the material was filtered and the filtrate was used for the measurements of pH value, ammonia nitrogen (NH3-N) and organic acids. The pH value was measured with a glass electrode pH meter (PHS-3C, CSDIHO Co., Ltd, Shanghai, China). Concentration of NH3-N was analyzed by Kjeltech analyzer according to Kjeltech method without a digestion step. The organic acid contents were analyzed by HPLC (column: Sodex RS Pak KC-811, Showa Denko K.K., Kawasaki, Japan; detector: DAD, 210 nm, SPD-20A, Shimadzu Co., Ltd., Kyoto, Japan; eluent: 3 mM HClO4, 1.0 mL/min; temperature: 60˚C). The pH changes of samples after exposure to the air for 48, 96 and 144 hours were measured. Data analysis. The data were analyzed by analysis of variance and means. Then it was compared for significance by Duncan’s multiple range method. All statistical procedures were performed using the statistical packages for the SAS and Excel.
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Results and Discussion Characteristics of banana stems and leaves Banana stems and leaves had higher contents of crude fiber, lower contents of crude fat and nitrogen free extract, lower contents of crude protein and water soluble carbohydrate (Table 1). Table 1 Nutrition and tannins content of banana stems and leaves (DM, %) Sample
DM
CP
CF
NDF
ADF
WSC
NFE
Tannins
22.11a
11.21b
2.87c
67.63ab
33.98c
6.52a
54.76bc
0.66a
Medium plantain
17.11a
14.96a
3.34b
67.92ab
39.30bc
6.24a
54.44bc
0.46b
Brazil banana
17.99a
8.16c
5.65a
72.57a
46.78b
6.43a
51.32c
0.24c
4.59b
1.53f
1.58d
73.88a
56.45a
5.64b
51.26c
0.08d
Medium plantain
4.67b
2.01e
2.18cd
64.05b
53.25a
5.48b
53.18b
0.10d
Brazil banana
4.52b
4.49d
1.35d
58.37c
46.96b
5.82b
54.55a
0.11d
Average
11.85
7.06
2.83
67.40
46.12
6.21
53.25
0.28
Banana leaves Dwarf banana Dongguan
Banana stems Dwarf banana Dongguan
DM, dry matter; CP, Crude protein; CF, Crude fat; WSC, water-soluble carbohydrate; NFE, Nitrogen free extract; ND, not detect; Neutral Detergent Fibre, NDF; Acid Detergent Fibre, ADF; Water soluble carbohydrate, WSC.
Remark: different letter in the same range stands for obvious differentiation (P＜0.01).
Average value of DM, CP, EE, NDF, ADF, Nitrogen free extract and Tannins in banana stem and leaf were 11.85%, 7.06%, 2.83%, 67.40%, 46.12%, 6.21%, 53.25%, and 0.28%, in which content of DM, CP, EE, and Tannins were obviously higher than banana stem(P＜0.01）. Because of the big amount of yield of Brazil banana, its leaf and stem (about 99% stem) were chosen as silage experiment material. Adhering microbes in banana stems and leaves. Microbes adhering to banana stems and leaves in three species of banana were analyzed. Analysis result was shown in Table 2. Table 2: The micro-organisms attached to the banana stems and leaves (cfu/g FM) Aerobic Sample
LAB
Bacilli
bacteria
Yeast
Mold
Dwarf banana leaf
6.5x105
ND
6.4x106
1.8x106
1.0x102
Dongguan medium plantain leaf
2.1x104
6.5x103
5.2x105
3.4x104
1.0x102
Brazil banana leaf
6.8x105
4.5x103
4.4x106
2.8x105
2.0x102
1.4x106
5.0x103
5.8x107
4.0x106
ND
6
4
8
6
1.0x102
6.5x106
2.0x102
Banana leaf
Banana stem Dwarf banana stem Dongguan medium plantain stem
2.8x10
Brazil banana stem
6.0x106
2.5x10
6.5x103
2.3x10
6.4x107
7.0x10
ND：not detect. LAB: Lactic acid bacteria.
There were many LAB in Brazil banana leaf and stem which was 6.8x105 cfu/g FM, 6.0x106 respectively. There was a big amount of Bacilli in Dongguan medium banana leaf and stem which were 6.5x103cfu/g FM, 2.5x104 respectively. There were many Aerobic bacteria in Dongguan medium plantain stem, and the second most was in Brazil banana stem. There were a big amount of
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Yeast in Dongguan medium plantain; the second most was in Brazil banana stem. Except for Dwarf banana stem, there were a few mould adhere in banana stems and leaves. Aerobic bacteria, followed by Yeast and LAB, ranked first in quantity among microbes adhering in banana stems and leaves. Fermentation quality of banana stems and leaves silage Organic acid content was the main indicator valuing fermentation quality of silage. Analysis result of organic acid in banana stems and leaves silage was shown in Table 3. Table 3 The ratio of concentrations of organic acid of banana stems and leaves silage (%FM) Group number I（contrast） II III IV
Lactic acid d
0.84 0.90c 1.32b 1.62a
Acetic acid 0.42b 0.43b 0.46a 0.45a
Propionic acid 0.16b 0.19a 0.14c 0.17b
Butyric acid 0.03a 0.03a 0.01a 0.00a
pH 4.6a 4.3b 4.1c 3.9d
Remark: different letters in the same range shown significant difference (p
