多菌混合发酵豆豉后发酵工艺优化及品质分析

Optimization of post-fermentation process and quality of Douchi by multi-bacteria fermentation

为探究多菌混合发酵豆豉的发酵工艺和品质,该研究以大豆为原料,枯草芽孢杆菌(Bacillus subtilis)、卡利比克迈耶氏酵母(Meyerozyma caribbica)、溜曲霉(Aspergillus tamarii)为菌种制备豆豉,通过单因素试验结合响应面试验优化多菌混合发酵豆豉后发酵工艺条件,并对其后发酵过程中的理化、微生物指标及酶活力进行分析。结果表明,最优豆豉后发酵工艺条件为食盐添加量7%,发酵温度33℃,发酵时间8 d。在该优化条件下,豆豉感官评分为86.33分。后发酵完成时,豆豉水分含量、还原糖、总糖、总酸、总游离氨基酸、氨基酸态氮含量、颜色参数L^(*)值、a^(*)值、b^(*)值分别为23.76%、2.13 g/100 g、5.40 g/100 g、0.22 g/100 g、0.319 g/100 g、0.77 g/100 g、65.03、6.10、19.83;细菌、酵母菌、霉菌、乳酸菌活菌数对数值分别为3.13、0.97、3.44、2.12;蛋白酶与淀粉酶活力分别为322 U/100 g、13 U/100 g。

To investigate the fermentation process and quality of Douchi by multi-bacteria fermentation,Douchi was prepared with soybean as raw material and Bacillus subtilis,Meyerozyma caribbica and Aspergillus tamarii as strains,the multi-bacterial mixed fermentation process conditions of Douchi were optimized by single-factor tests combined with response surface tests,and the physicochemical,microbial indexes and enzyme activity were analyzed during post-fermentation.The results showed that the optimal post-fermentation process conditions of Douchi were salt addition 7%,fermentation temperature 33℃and time 8 d.The sensory score of Douchi was 86.33 under the optimized conditions.After post-fermentation,the moisture,reducing sugar,total sugar,total acid,total free amino acids,amino acid nitrogen content and color parameters L^(*),a^(*),b^(*)value of Douchi were 23.76%,2.13 g/100 g,5.40 g/100 g,0.22 g/100 g,0.319 g/100 g,0.77 g/100 g,65.03,6.10,19.83,respectively.The logarithmic values of viable bacteria,yeasts,molds and lactic acid bacteria were 3.13,0.97,3.44 and 2.12,respectively.The protease and amylase activities were 322 U/100 g and 13 U/100 g,respectively.