米曲霉全小麦制曲条件的优化

Study on Optimization of Whole Wheat Koji-making Conditions of Aspergillus oryzae

以全小麦为米曲霉制曲原料,蛋白酶活力为指标,研究了小麦焙炒时间、曲料初始水分含量、曲精接种量、培养时间、外加营养物对成曲蛋白酶活力的影响。结果表明,米曲霉全小麦制曲的最优条件为:焙炒小麦30min、曲料初始水分55%(w/w)、曲精接种量0.05%(w/w)、培养时间46h、葡萄糖添加量0.3%(w/w)。在此条件下,小麦成曲的中性蛋白酶活力可达1424U/g(干基,下同),与大豆成曲相当;酸性蛋白酶活力可达486U/g,较大豆成曲提高62%。

The koji-making conditions of Aspergillus oryzae cultivated with whole wheat were optimized and the effects of wheat roasting time, initial moisture content of the koji, inoculum size, culture time and addition of nutrition on protease activity were studied. The results showed that the optimum koji-making conditions were as follows： wheat roasted for 30 min, initial moisture content 55% , inoculum size 0. 055% , culture time 46 h, and glucose 3%. Under above conditons, the neutral protease activity of wheat koji was 1424 U/g, equal to that of soybean koji. The acid protease activity was 486 U/g, 62% higher than that of soybean koji.