毛霉型豆豉后发酵阶段蛋白质水解产物的生成及影响因素

采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、反相高效液相色谱等方法对毛霉型豆豉后发酵过程中蛋白质及其水解产物的变化情况进行研究,对各阶段蛋白质水解产物与不同因素指标的相关性进行分析,并采用APIZYM系统对毛霉所产胞外酶进行半定量检测。结果表明:蛋白质最终水解产物的分子质量主要集中在11~20 kD之间,后发酵0~7 d蛋白质分子质量下降迅速,且此阶段多肽成分发生较大改变,7~42 d主要引起的是多肽含量的变化;总酸含量与蛋白质水解物生成的相关性最高,相关系数为0.972,其次为褐变强度,再次为还原糖含量;API ZYM系统检测出毛霉可产生6种胞外酶。

Formation of Protein Hydrolysate and Its Influencing Factors during the Post-Fermentation of Mucor-Type Douchi,a Chinese Traditional Fermented Soybean Product

This study analyzed the change of protein and its hydrolysate during the post-fermentation of Mucor-type douchi by SDS-PAGE and reversed-phase liquid chromatography (RP-LC). The correlation of free amino acid content with different chemical components and browning intensity was analyzed, and the extracellular enzymes from Mucor were semi-quantitatively detected by the API ZYM system. The results showed that the molecular weight of the final protein hydrolysate was mainly distributed in the range of 11–20 kD. The molecular weight of proteins was reduced rapidly at the early stage (from day 0 to 7), and the polypeptide composition changed greatly. The polypeptide content changed from day 7 to 42. The formation of free amino acids had the highest correlation with the total acid content with a correlation coefficient of 0.972, followed sequentially by the browning intensity and reducing sugar. Using the API ZYM system we detected 6 extracellular enzymes from Mucor.