Study On Increaseing The Hydrolysis Degree Of Fermented Soybean Meal By Exogenous Enzyme

Soybean meal (SBM) of high nutritional value is one of the most useful feedstuff in feed industry. But a large number of anti-nutritional factor exist in SBM limit its further application. Now SBM is usually fermented by microbial, those can produce various enzyme to depredate the macromolecular protein and anti-nutritional factor when grow in SBM. But the growth is probably not that well because the SBM, without any pretreatment before fermentation, is not the optimal medium for microbial. As a result, the quality of the fermentation product is instable.As an assistant, exogenous enzyme can improve the stability of product. And because the cutting sites are not specific, it can continue to break the balance of enzyme reaction system to improve the efficiency of hydrolysis.The objectives of this study were to determine the optimal parameters by fermentation and enzymatic degradation of soybean meal with bacillus and neutrase, and to evaluate the nutrient composition of the fermented soybean meal (FSBM).The main achievement were as follows:1,We have obtained a bacillus named F which had a stronger ability to hydrolyzethe soybean protein. The degree of hydrolysis (DH) of the FSBM was 14.091%.2,On the basis of fermentation by F, the effects of the supplementing levels ofneutrase, cellulase, pectinase and xylanase on the DH were evaluated, and theoptimal fermentation parameters were established. The results showed that treatmentof SBM by neutrase and F together could achieve good hydrolyzed results. The DHwas 21.027%.3,A orthogonal design of L₁₆ (4⁵) was conducted to determine the optimal fermentation parameters. The results showed that the optimal parameters were proteinase concentration of 50μ/g, inoculation quantity of 1.5%, anticipate water to compare 1: 1.2, temperature of 35℃, fermentation period of 48 h, and the DH was up to 21.027%.4,Studied on the nutrient composition of the product under the optimal conditions, compared with raw soybean and the product under the conditions before optimized, the FSBM fermented under optimal condition:The conventional nutrition composition and amino acid content increased in varying degrees, especially the TCA nitrogen content,the Soybean Isoflavone content and Met&Lys,the amino acid that FSBM usually shorted of, respectively the concentration were up to 31.42%,1.9 (OD_260nm),1.34% and 3.38%; The macromolecular protein suffered a further decrease, the Mw was lower than 2700Da, and the content of functional oligopeptide was increased greatly; nutrition anti-factor and most soybean antigen suffered a degradation and elimination.