The Preliminary Studies On Improving The Quality Of Peanut Meal With Microbial Fermentation

In this study, one strain Lactobacillus casei was screened from moldy peanuts and peanutmeal with the characters of removing aflation, fast growing and producing lactic acid, andaccording with the variety catalogue of feed additives. Peanut meal was fermented by strain ofLactobacillus casei and combined with enzymes. The fermentation conditions were optimized.With the optimaized fermentation process, the protein digestibility was improved, aminoacids profile was balanced, more aflatoxin B1was removed, and more anti-nutritional factorssuch as phytic acid, were degraded. While as more lactic acid was accumulated and the safetyquality and the nutritive value of feed were improved.One strain of Lactobacillus sp.was screened by compared the ability of removingaflatoxin B1and producing lactic acid from moldy peanut and moldy peanut meal. It wasidentified as Lactobacillus casei by16S rDNA, and named as Lactobacillus casei R-07in thisstudy. It conformed to the the variety catalogue of feed additives..Combined with the single factor experiments and uniform design experiments, the solidstate ferment conditions were optimized. It was that the raw material treated at100℃for1min, fermented at35.8℃for48h with10%inoculation volume, ratio of material to waterwas1:0.8, acid protease was added by100U/g, phytic acid enzyme was added by1.5U/g. Inthese conditions, the number of L. cacei reached to2.35×10¹⁰cfu/g, and the contents ofpeptide, aflatoxin B1and total acid were15.66±0.43%,13.01±0.98ng/g, and6.73±0.27%,respectively.After the peanut meal being fermented by the strain of Lactobacillus casei R-07, thecontent of essential amino acid was improved by16.43%, the content of peptide wasimproved from3.34%to16.36%, in vitro protein digestibility was improved from57.45%to68.36%, and the content of anti-nutritional factor phytic acid was decreased from1.36%to0.23%. Meanwhile, the content of inorganic phosphorus was increased from0.11%to0.40%.Furthermore, the fermented sample was found to be able to partially inhibit the growth ofEscherichia coli. The structure of the microorganisms in fermented peanut meal wasrelatively simple, with major of Lactobacillus. Comparatively, the unfermented peanut mealhas rather more categories and quantities of contaminated microorganisms. With the increaseof storage time, the structure of the microorganisms in control peanut meal was found to bemuch more complex. In contrast, the fermented peanut meal with a less number ofcontaminated microorganisms and the Lactobacillus died gradually, could extended thestorage period.