米曲霉和乳酸菌混合制曲对小麦大曲制曲效果的影响

本文研究了米曲霉和乳酸菌混合制曲(KR)及米曲霉单独制曲(KP)条件下,小麦大曲中菌落总数、中性蛋白酶活力、酸性蛋白酶活力、总酸以及发酵液品质,探讨了多菌种制曲的可行性,以期为高品质小麦基调味料的生产提供理论指导。研究结果表明:KR工艺中小麦大曲的乳酸菌和霉菌均繁殖良好,12 h时乳酸菌达到了4.15×108 cfu/g,乳酸菌的繁殖对霉菌的生长有一定的抑制效果;米曲霉和乳酸菌混合制曲比米曲霉单独接种制曲效果好,制曲48 h时,KR工艺所得到的大曲中性和酸性蛋白酶与米曲霉纯种制曲相比,分别提高了22.79%和22.26%;KR大曲发酵液的全氮含量、氨基酸态氮含量均高于KP工艺,发酵60 d时KR发酵液的游离氨基酸含量高于KP,其中谷氨酸含量明显提高,对比KP工艺提高了24.21%,具有更明显的鲜味口感。

Effects of Aspergillus oryzae and Lactic acid bacteria Mixture on Wheat Koji-making

The total bacterial count ,neutral protease activity, acid protease activity, total acid and the quality of fermented liquid in separated koji-making by Aspergillus oryzae (KP) and mixed koji-making by Aspergillus oryzae and Lactic acid bacteria (KR) were measured in this paper. The feasibility of multi-strains for koji-making was discussed to provide theoretical guidance for high quality of wheat tasty substance. The results showed that lactic acid bacteria and fungi grew well in KR system, and the count of lactic acid bacteria was reached 4.15×108 cfu/g after 12 h, while the growth of lactic acid bacteria had inhibitory action on fungi growth; the effect of mixed koji-making was better than separated koji-making in all respects. The neutral protease activity and acid protease activity of KR after 48 h fermentation were increased by 22.79% and 22.26% compared to KP, respectively. The total nitrogen content and amino acid nitrogen content in KR fermentation liquor were more than those in KP. However, the free amino acid content in KR system was more than that in KP after 60 days fermentation. Especially, glutamic acid was improved by 24.21%, making the fermentation liquid more obvious umami taste.