Study On Solid-state Fermentation Of Soybean Meal

Soybean meal is one of the high-grade vegetable protein sources.Its resource and nutrition are rich.But there are many kind of anti-nutrition factor in soybean meal which greatly influences its utilization in young stock's feed.Nowadays people mainly use chemical or physical method to eliminate the anti-nutrition factors of soybean meal.It always costs too much and unsafe,although it has effect on elimination of anti-nutrition factors.We choose the microbe fermentation method to treat soybean meal so that to research the effect of microbe fermentation on anti nutrition factor and nutrition value of soybean meal.Experiment 1:Influence of different strains and fermentation conditions on anti-nutrient factors of fermented soybean meal.In this study,we used bacillus subtilis,bacillus cereus,lactobacillus,clostridium butyricum to apply polyfactorial experiment design to study the effect of inoculum size,moisture capacity and fermentation time on contents of anti-nutrition factors and small peptide in fermented soybean meal. Througth the experiment we concluded that:The elimination coefficient of trypsin inhibitor and phytic acid were 65.36%,83.45%fermentated by bacillus subtilis when inoculum size was 9%,moisture capacity was 1:1 and fermentation time was 48h(P＜0.01 ), respectively,Lipoxygenase were eliminated completely under the same conditions (P＜0.01).The effects of Bacillus subtilis on elimination of trypsin inhibitor is the best in all four strains we used.The elimination coefficient of lectin were 90%fermentated by bacillus subtilis when inoculum size was 9%,moisture capacity was 1:1.2 and fermentation time was 48h(P＜0.01).Experiment 2:Effect of mixed culture fermentation on anti-nutrient factors of soybean Meal.In this study,we used raw soybean meal as raw material,and select bacillus subtilis,bacillus cereus,lactobacillus,clostridium butyricum to carry out the mix swains fermentation.Applying L₂₇(3¹³) orthogonal experiment design to study the effect of different mixed culture fermentation inoculum size ratios on anti-nutrition factors in fermented soybean meal.It was concluded that the best multi-strains inoculum size ratio was bacillus subtilis:bacillus cereus:laobacillus plantarum:clostridium butyricum= 6%:4%:4%:4%,that can removal the chief anti-nutrition factors in soybean meal greatly. The elimination coefficient of trypsin inhibitor,phytic acid and soybean protein were 75.89%,86.71%and 100%fermentated by bacillus subtilis when temperature was 34℃, moisture capacity was 1:1 and pH was nature(P＜0.01).The results show that on removing trypsin inhibitor effects of bacillus subtilis affected significantly(p＜0.01), Bacillus cereus affect significantly(p＜0.05).Removed of phytic acid with multi-strains fermentation,bacillus subtilis and lactobacillus both had significant impact(p＜0.05),and bacillus subtilis also had a very significant impact(p＜0.01) on improve peptide content in soybean meal fermented.Soybean protein was nearly eliminated completely.Experiment 3:Study of mixed culture fermentation optimization fermentation condition.In this study,we used raw soybean meal as raw material,and selected the best inoculum size ratio of multi-strains was bacillus subtilis:bacillus cereus:laobacillus plantarum:clostridium butyricum=6%:4%:4%:4%,apply five levels monomodule experiment design to study the effect of temperature,initiatial pH,moisture capacity and fermentation time on multi-strains fermentation effectiveness and determining the best multi-strains fermentation conditions.Comprehending the results,we conclude that bacillus subtilis 6%,bacillus cereus 4%,lactobacillus 4%,yeast fungus 4%,moisture capacity1:1,40℃,60h,initiatial pH natural are the best fermentation conditions.Finaly,, the content oftrpsin inhibitor,phytic acid and lectin were10.21mg/g,0.07%and 3.216ug/g, respectively.And the elimination coefficient of them were 79.44%,90.62%and 99.69%. The activity of lipoxygenase-1 was 0.125,its elimination coefficient was 90%. Lipoxygenase-2 was completely eliminated,and the elimination coefficient of soybean protein was more than 95%.And the content of small peptide increased from 2.7%to 11.98%.