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

Rapeseed meal was fermented through mixing Bacillus Subtilis-2 with Pediococcus pentosaceus-1 for promoting its comprehensive quality.Firstly, 205 strains isolated from rapeseed meal were screened through cultivating in the medium with glucosinolate as a sole carbon source and 22 strains with good growth (OD600> 0.6) were obtained. Secondly, 6 strains of Lactic acid bacterium were achieved according to the degradation ability of glucosinolates. Finally, 1 strain of Pediococcus pentosaceus-1 was achieved through re-screening in the solid-state fermentation.whose degradation rate of glucosinolates was 62.11%.Meanwhile, three kinds of strains including Bacillus SubtiLis, Bacillus megaterium and Bacillus licheniformis preserved in the Laboratory were screened by determination of peptide content and SDS-PAGE analysis of rapeseed meal under solid-state fermentation. And finally, a strain of Bacillus subtilis with good protein degradation ability was achieved.Furthermore, the fermentation conditions for rapeseed meal were optimized by mono factor experiment and orthogonal experiment. The optimal conditions were as follows: fermentation at 35℃for 48h with the inoculation of 20%, inoculating Pediococcus Pentosaceus at 6th hour, liquid ratio 1:1, inoculation ratio 1:3 for Bacillus subtiLis-2 to Pediococcus pentosaceus-1 .under these conditions: the contents of peptide, glucosinolate and total acid were 10.25±0.43%, 20.15±0.65μmol/g, and 3.57±0.27%, respectivelyAs a result, the quality evaluation system for fermented rapeseed meal was initially established. Indexes were as follows: glucosinolate content≤25μmoL/g, the crude protein content≥43%, hydrolyzed amino acids content≥33%, 12S globulin degradation rate≥80%, peptide content within a molecular weight of 5 kDa≥9%, the rapid in vitro digestion increased by 1.5%, Lactic acid content≥2.5%.