酱油制曲过程中蛋白质的降解规律研究

研究了酱油制曲过程中总氮含量、氮溶指数、氨基酸转化率、挥发性盐基氮含量及可溶性多肽分子量分布的变化规律;结果表明:豆粕曲和大豆曲的总氮含量、氮溶指数、氨基酸转化率均随培养时间的延长呈上升趋势,培养48h后,豆粕曲和大豆曲的总氮含量分别提高了15.89%和12.43%,豆粕曲和大豆曲的氮溶指数分别达到26.37%和34.45%;氨基酸转化率分别达到12.11%和16.00%,大曲的氨基酸转化率与氮溶指数呈明显正相关。不同培养时段的豆粕曲和大豆曲的肽分子量均以1000～5000u为主,制曲结束后,分别占肽总量的63.55%和67.62%。

Study on protein degradation rules during soy sauce koji-making

The aim was to study the changes of total nitrogen content,NSI,amino acid conversion rate,TVB-N content and molecular weight distribution.The results showed that the total nitrogen content and amino acid conversion rate of both soybean koji and defatted soybean koji increased during fermentation.After cultivation for 48h,the total nitrogen contents of soybean koji and defatted soybean koji increased by 15.89% and 12.43%,and NSI increased by 26.37% and 34.45% respectively.The conversion rates of amino acid in defatted soybean kojis and soybean koji increased by 12.11% and 16.00%,respectively.The amino acid conversion rate and NSI of koji had significantly positive correlation.Molecular weight of peptides was mainly distributed between 1000u and 5000u,accounting for 63.55% and 67.62% of the total peptides in mature soybean koji and defatted soybean koji,respectively.