复合菌与复合酶联合处理对大豆皮营养成分及品质的影响

Effects of multiple strains fermentation and enzymatic hydrolysis on nutrient composition and quality of soybean hulls

摘要:

[背景] 大豆皮纤维含量较高，而且含有多种抗营养因子如脲酶和抗原蛋白等，限制了大豆皮的利用。[目的] 通过菌酶联合处理以进一步降低大豆皮中的纤维和抗营养因子含量，利用此方法在实验室进行大豆皮的袋装处理，评价大豆皮的营养价值及品质，为大豆皮的产业化利用奠定基础。[方法] 实验分为4组，对照组（未经菌株发酵和酶解处理的大豆皮）、菌株发酵组（乳酸杆菌、芽孢杆菌和酵母菌复合发酵组）、酶解组（纤维素酶和木聚糖酶酶解组）及酶解+菌株发酵组（乳酸杆菌、芽孢杆菌和酵母菌+纤维素酶、木聚糖酶，菌酶发酵组），研究复合酶和复合菌联合处理对大豆皮营养价值及品质的影响，筛选袋装处理的最佳时间。[结果] 与对照组相比，发酵组的pH值、还原糖、脲酶活性、球蛋白和β-伴大豆球蛋白含量下降（P<0.05）；酶解组的还原糖、粗蛋白、真蛋白含量显著提高（P<0.05），中性洗涤纤维、酸性洗涤纤维显著下降（P<0.05）；菌酶发酵组的还原糖、粗蛋白和真蛋白的含量显著提高（P<0.05），pH值、中性洗涤纤维和酸性洗涤纤维的含量显著降低（P<0.05）。与发酵组相比，菌酶发酵组的乳酸浓度和活菌数较高，pH值、脲酶活性、球蛋白和β-伴大豆球蛋白显著降低（P<0.05）；与酶解组相比，菌酶发酵组还原糖浓度、中性洗涤纤维、酸性洗涤纤维和半纤维素显著下降（P<0.05）。袋装实验中，在最佳发酵时间5 d时，菌酶发酵组的pH值为4.87，显著低于其他组（P<0.05）；与发酵组相比，菌酶发酵组的还原糖、粗蛋白、真蛋白含量显著提高（P<0.05），脲酶活性、球蛋白、β-伴大豆球蛋白、中性洗涤纤维、酸性洗涤纤维和半纤维素显著下降（P<0.05）。与酶解组相比，菌酶发酵组的还原糖、中性洗涤纤维、酸性洗涤纤维和半纤维素含量显著降低（P<0.05），菌酶发酵组中霉菌含量仅为0.89 lg（CFU/ml），显著低于其他组（P<0.05）。[结论] 菌酶结合处理大豆皮可通过提高粗蛋白、真蛋白的含量，降低纤维和抗营养因子含量，抑制大豆皮中霉菌的产生，显著改善大豆皮的营养价值及品质。

Abstract:

[Background] Soybean hulls as a crude feed have high digestibility, but their fiber content is high, and contains a variety of anti-nutritional factors such as urease and antigen protein, which limits its application in monogastric animal feed. [Objective] The aims of this study to reduce the content of fiber and anti-nutritional factors in soybean hulls by combination of bacteria fermentation and enzymatic hydrolysis. The packaging treatment of soybean hulls by using this method was conducted in the laboratory to evaluate the number of molds and the nutritional value and quality of soybean hulls for the foundation of future industrial application of soybean hulls. [Methods] The experiment was divided into four groups:control group (soybean hulls without fermentation and enzymatic hydrolysis group), strain fermentation group (Lactobacillus, Bacillus, and Saccharomyces mixture fermentation), enzymatic hydrolysis group (cellulase and xylanase enzymatic hydrolysis), and enzymatic hydrolysis + strain fermentation group (Lactobacillus, Bacillus and Saccharomyces compound fermentation + cellulase and xylanase enzymatic hydrolysis). The optimal time for packaging treatment was selected. [Results] Compared with the control group, the pH value, reducing sugar content, urease activity, globulin, and β-conglycinin of the fermentation group were decreased (P<0.05). The reducing sugar, crude protein, and true protein content in the enzymatic hydrolysis group was increased (P<0.05), while the neutral detergent fiber and acid detergent fiber were decreased (P<0.05). The pH value, the contents of neutral detergent fiber, and acid detergent fiber were decreased (P<0.05), while the reducing sugar content, crude protein, and true protein contents were increased (P<0.05) in the bacteria fermentation and enzymatic hydrolysis group. Compared with the fermentation group, lactic acid concentration, and viable bacteria number were higher, while pH value, urease activity, globulin, and β-conglycinin were decreased in the bacteria fermentation and enzymatic hydrolysis group (P<0.05). Compared with the enzyme hydrolysis group, the reducing sugar concentration, the neutral detergent fiber, acid detergent fiber, and hemicellulose in the bacteria fermentation and enzymatic hydrolysis group were decreased (P<0.05). In the bag experiment, the pH value of the enzyme fermentation group was 4.87 at the optimal fermentation time of 5 d, which was lower than that of the other groups (P<0.05). Compared with the fermentation group, the reducing sugar content, crude protein, and true protein in the bacteria fermentation and enzymatic hydrolysis group were increased (P<0.05), while the urease activity, globulin, β-conglycinin, neutral detergent fiber, acid detergent fiber and, hemicellulose in the bacteria fermentation and enzymatic hydrolysis group were decreased (P<0.05). Compared with the enzymatic hydrolysis group, the reducing sugar content, neutral detergent fiber, acid detergent fiber and, hemicellulose in the bacteria fermentation and enzymatic hydrolysis group were decreased (P<0.05). The content of mold in the bacterial enzyme fermentation group was only 0.89 lg(CFU/mL), which was lower than that in the other groups (P<0.05). [Conclusion] The combination of bacteria and enzymes can increase the crude protein and true protein content, reduce the content of fiber and anti-nutritional factors, inhibit the production of mold in soybean hulls, and finally improve the nutritional value and quality of soybean hulls.