东山老米酒酿造过程中酵母菌的分离鉴定及其品质分析

目的 本文对传统东山老米酒的发酵特性进行了比较全面研究。方法 首先利用26S rDNA序列分析法对酒曲中的酵母菌进行了分离鉴定,借助高效液相色谱法测定酒中的氨基甲酸乙酯,利用气相色谱-质谱联用法分析了老米酒中的风味物质,同时还用氨基酸自动分析仪测定了游离氨基酸种类。结果 分离得到的菌株有3株为酿酒酵母,1株为白色隐球菌；老米酒中氨基甲酸乙酯含量处于较低水平,尤其是陈酿中仅含0.6 mg/L；风味物质以醇、酯类为主,如苯乙醇、琥珀酸二乙酯,酯类随酒的陈化而逐渐增多；老米酒中组氨酸和精氨酸含量较高,导致酒中苦味氨基酸含量高于60%,同时氨基酸含量在陈化过程中逐渐下降。结论 东山老米酒的发酵以酵母发酵为主,发酵产生的氨基甲酸乙酯的含量处于较低水平,且随着老米酒的陈化而降低。

Isolation, identification and quality analysis of yeasts in the brewing process of Dongshan old rice wine

Objective To explore the main yeast strains, typical flavor components and changes of ethyl carbamate in Dongshan old rice wine by studying the fermentation characteristics of traditional Dongshan old rice wine. Methods Firstly, yeast of Dongshan old rice wine was isolated and identified by 26S rDNA sequence analysis, the ethyl carbamate was determined by high performance liquid chromatography, and the volatile flavor compounds were determined by gas chromatography-mass spectrometry instrument, at the same time, the free amino acids were determined by amino acid automatic detector. Results Three strains isolated were Saccharomyces cerevisiae, and one strain was Cryptococcus albidus; the content of urethane in rice wine was at a relatively low level, especially the content of ethyl carbamate in aged wine was significantly lower than that in new wine (P<0.05); the flavor substances were mainly alcohols and esters, such as phenethyl alcohol and diethyl succinate, the esters were gradually increased with the aging of the wine; the content of histidine and arginine in rice wine were higher, resulting in the bitter amino acid content in the wine being higher than 60%, while the amino acid content was gradually decreased during aging. Conclusion The fermentation of Dongshan old rice wine is mainly by yeast fermentation, and the content of ethyl carbamate produced by fermentation is at a low level, and decreases with the aging of old rice wine.