Evaluation of six commercial koji on the formation of biogenic amines and higher alcohols in rice wine

Commercial koji are increasingly used as the microbial inoculum in the production of rice wine. This study reports on the use of six commercial koji on rice wine brewing and shows that the microbial composition varied significantly among the different koji. Of the koji, AQ (An Qi) and YB (Yi Bin) contained fewer microflora but exhibited higher starch degradation and wine production efficiency. The Two-way Orthogonal PLS model and Pearson correlation analysis suggests that the presence of biogenic amines in rice wine was related to contaminating microorganisms in the koji including Lactobacillus, Kosakonia, Pantoea, Ralstonia, Kosakonia and Pantoea. The formation of higher alcohols is related to Saccharomyces species. Screening of beneficial yeasts with low production of higher alcohols and avoiding contamination by unwanted bacteria are suggested for improving the quality of rice wine. © 2022 The Institute of Brewing & Distilling.