紫红曲霉与酿酒酵母共发酵对红曲甜米酒风味的影响

研究紫红曲霉和酿酒酵母在红曲甜米酒发酵过程中风味物质形成的作用。利用紫红曲霉和酿酒酵母以不同比例复配进行甜米酒发酵,监测微生物、有机酸和挥发性香气成分的动态变化。结果表明,以发酵12 h为分界点,酵母菌先增加后减少,而红曲菌则同步呈先减少后增加的趋势;添加红曲菌能够显著促进酵母菌增殖。发酵过程中,酒样的糖度不断降低,酒精度不断增加,发酵36 h后有机酸(乳酸、乙酸、柠檬酸、酒石酸)含量迅速增加;随着红曲菌添加量的提高,糖度减少,酒精和有机酸含量均显著增加。发酵过程共检出47种挥发性组分,包括6种醇类、14种酸类、12种酯类、8种醚类、4种醛酮类、2种醌类和1种酚类,其中高级醇类(苯乙醇、香草醇、异丁醇)和酯类(对羟基扁桃酸乙酯)相对含量较高;酸类含量随发酵时间的延长不断减少,而醇类、酯类和醚类含量则不断增加;添加红曲菌使酯类在发酵前期迅速增加,显著提高其含量。综上所述,添加红曲菌共发酵,促进了酿酒酵母增殖,显著增加了有机酸和酯类等挥发性组分的种类和含量,对甜米酒风味物质的丰富具有重要贡献。

Influence of Monascus purpureus and Saccharomyces cerevisiae Co-fermentation on the Flavor of Sweet Red Yeast Rice Wine

In order to investigate the influence of Monascus purpureus and Saccharomyces cerevisiae co-fermentation on the flavor of sweet red yeast rice wine,the two different strains in various proportions were combined and used for rice wine fermentation.The dynamic changes of microorganisms,organic acids and volatile aroma components were monitored during fermentation,aiming to reveal the causal relation between microbial fermentation and flavor compounds production.Microbial count showed that yeast increased in the early 12 h and then began to decrease,and Monascus correspondingly decreased in the beginning and then increased gradually during fermentation.But addition of Monascus obviously promoted yeast proliferation.Moreover,the alcohol content increased slowly as sugars were consumed during fermentation,and more organic acids were produced after 36 h of fermentation,which were mainly composed of lactic acid,acetic acid,citric acid,and tartaric acid.Remarkably,higher inoculum size of Monascus used in fermentation resulted in more sugar consumption and more alcohol and organic acids production in rice wine.Furthermore,47 volatile components in total were detected during fermentation,including 6 alcohols,14 acids,12 esters,8 ethers,4 aldoketones,2 quinones,and 1 phenol,in which higher alcohols(2-phenylethanol,vanillyl alcohol,isobutanol)and esters accounted for the highest content.The relative contents of acids decrease constantly,while the relative contents of alcohols,esters,and ethers increased during fermentation.Besides,addition of Monascus prominently led to a rapid increase in esters production in early fermentation and a final higher concentration of esters.To sum up,addition of Monascus in rice wine fermentation promoted the proliferation of yeast and the generation and enrichment of diverse organic acids and volatile components,especially the esters.Co-fermentation of M.purpureus and S.cerevisiae significantly contributed to the abundant flavor compounds in sweet red yeast rice wine.