以枯草芽孢杆菌(Bacillus subtilis J3)和植物乳杆菌(Lactobacillus plantarum JNX)为发酵菌株,以发酵产物中小肽含量和挥发性盐基氮含量为检测参数,优化了混合菌固态发酵豆粕以制备大豆肽的生产工艺参数,并对发酵产生的大豆肽的性质进行了初步研究。确定的固体发酵工艺为:植物乳杆菌和枯草芽孢杆菌菌种比例为2∶1、料水比1∶0.6、接种量6%、30℃发酵24 h,该条件下发酵产物中小肽含量最高为10.64%,挥发性盐基氮含量最低为50.70 mg/100 g。SDS-PAGE电泳结果表明,发酵后豆粕提取液中的蛋白类产物的分子质量均为10k Da以下,其抗氧化活性最高可达65.76%。氨基酸组成成分分析表明,混合菌固态发酵豆粕后的提取液中甲硫氨酸、亮氨酸、缬氨酸、苯丙氨酸和异亮氨酸等必需氨基酸的含量提高了5倍以上。

Soybean meal was inoculated with Bacillus subtilis J3 and Lactobacillus plantarum JNX. The soybean peptides were prepared through solid-state fermentation with one-variable-at-a-time strategy,using the contents of small peptides and volatile basic nitrogen as parameters. The soybean peptides were characterized. The highest content of small peptide reached 10. 64% and the lowest content of volatile basic nitrogen was 50. 70 mg /100 g under the optimized conditions as follows: the ratio of L. plantarum JNX to B. subtilis J3 was 2∶ 1,the ratio of material to water was 1∶ 0. 6,inoculum concentration was 6%,soybean meal was fermented at 30℃ for 24 h. The results of SDS-PAGE showed that soybean meal was degraded to small peptides with molecular weight below 10 k Da and the antioxidant activity of soybean peptides reached 65. 76% after soybean meal was fermented at 30℃ for 48 h. The analysis of amino acid components showed that the content of essential amino acid including Methionine,Leucine,Valine,Isoleucine,Phenylalanine etc. was 5 times higher in the fermented products than that in the un-fermented products.