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Differential Research On Nutritional Quality Of Soybean Meal Solid-state Fermented By Different Strain Microbes

Posted on:2015-08-17Degree:MasterType:Thesis
Country:ChinaCandidate:T T FuFull Text:PDF
GTID:2181330422489034Subject:Food, grease and vegetable protein engineering
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Soybean meal (SBM) as a high quality protein feedstuff has many advantages,such as high crude protein content, ideal amino acid composition, high bioavailability,and so on. Howevre, there are many antinutritional factors in SBM (antigen protein,stachyose, raffinose), that influence the feed value of SBM. The solid-statefermentation of SBM can effectively degrade antinutritional factors and improve thefeed value of SBM. Under the same substrates and culture condition, The current studyuses the method of solid-state fermentation (SSF) to produce fermented soybean mealunder the same substrates and culture condition, and compare the effect of four kindsmicrobes on nutritional quality fermented soybean meal. The research mainly includesfour aspects:1. The screening of microbe strains for solid-state fermentation of SBMThis study screened out two strains microbes by flat transparent circle method.After identification of micromorphology and molecular biology, they are Bacillussubtilis and Enterococcus faecium, respectively. Besides, Saccharomycetes8605andCandida utilis stored in our laboratory were also used for SSF.2. Research on the characteristics of strains for SSFTo confirm the proliferative activity and inoculative time of the selectedmicrobial cells, the growth curves in liquid medium were determined. The resultshowed that the optimal inoculation time of8605, C. utilis, B. subtilis and E. faeciumwas20,24,20and14h, respectively. The viable cell counts of8065, C. utilis, B.subtilis and E. faecium were increased by6.38,82.26,3.64and3.02times. In addition,the FSBM had good sensory characteristics, golden color, fermentative fragrance andhigh viscosity.3. Nutrition composition analysis of SBM fermented by four microbesThe content of crude protein, acid soluble protein, small peptides and amino acid increased by17.71%,15.01%,9.01%and15.19%in SBM after48h fermentation with8605. The content of crude protein, acid soluble protein, small peptides and amino acidincreased by13.15%,11.15%,7.31%and15.70%in SBM after48h fermentation withC. utilis. The content of crude protein, acid soluble protein, small peptides and aminoacid increased by11.30%,9.8%,4.4%and21.01%in SBM after48h fermentationwith B. subtilis. The content of crude protein, acid soluble protein, small peptides andamino acid increased by10.65%,8.41%,3.62%and9.46%in SBM after48hfermentation with E. faecium. The content of lactic acid in FSBM increased by6.2,17.0,5.0and34.0times after fermentation with8605, C. utilis, B. subtilis and E.faecium, respectively.4. Antinutritional factors composition analysis of FSBM by four microbesAfter SBM fermented by8605, the urease inactivated rate was91.71%, stachyoseand raffinose were fully degraded, the degradation rate of globulin and β-conglycininwas8.64%and8.86%. After SBM fermented by C. utilis, the urease inactivated ratewas96.58%, stachyose and raffinose were also fully degraded, the degradation rate ofglobulin β-conglycinin was29.25%and29.26%. The urease inactivated rate was87.07%, the degradation rate of stachyose was23.38%, the degradation rate ofraffinose was48.85%, the degradation rate of globulin β-conglycinin was6.86%and6.61%, after the SBM fermented by B. subtilis. The urease inactivated rate was46.29%, the degradation rate of stachyose was46.29%, the degradation rate ofraffinose was50.97%, and the degradation rate of globulin β-conglycinin was24.81%and10.83%, after SBM fermented by E. faecium.In conclution, fermentation processes can improve the nutritional quality andeffectively degrade the antinutritional factors of SBM. Different microbes fermentioncan cause the nutrients variation of FSBM.8605, C. utilis, B. subtilis and E. faeciumcan be as the better microbial strains to produce fermented soybean meal.
Keywords/Search Tags:Soybean meal, Solid-state fermentation, Yeast8605, Candida utilis, Bacillus subtilis, Enterococcus faecium, Nutritional values, Anti-nutritional factors
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