耐低温酵母的分离鉴定及对低温酿造米酒品质的影响

Isolation and Identification of Cold Adaptive Yeast and Its Influence on the Quality of Low Temperature Brewing Rice Wine

为筛选适合低温酿造米酒的酵母菌株,本研究从米曲中分离纯化、筛选出低温下产香舒适、发酵能力优良、产酒精能力和产酯能力强的酵母,通过形态观察及分子生物学方法对其进行菌种鉴定,分析其生长情况和耐受性,并将其应用于低温酿造米酒。结果表明,分离、筛选得到一株耐低温酵母菌株XQ2-8,经鉴定为酿酒酵母(Saccharomyces cerevisiae)。与对照菌株相比,菌株XQ2-8在15℃下生长曲线的延滞期变短、达到稳定期时的生物量更高,具有较好的耐低温特性。菌株XQ2-8对生长环境具有一定的耐受性,可在乙醇体积分数8%vol、葡萄糖含量60%、pH3.0、低温10℃条件下正常生长。利用菌株XQ2-8酿造米酒,与常温酿造相比,低温米酒的总酯含量(60.08 mg/L)和甘油含量(2.59 g/L)分别提高了15.6%、22.7%;总酸含量(1.91 g/L)和总高级醇含量(578.20 mg/L)分别降低了18.0%、17.7%;感官得分(89.47)提高了11.7%。说明利用筛选得到的菌株XQ2-8低温酿造可以改善米酒中酯类含量低、高级醇含量偏高的问题,提高米酒品质。

In order to screen yeast strains suitable for low-temperature brewing rice wine,this study isolated and purified and screened yeast with comfortable aroma production,excellent fermentation capacity,alcohol production capacity and ester production capacity at low temperature from rice bent,and identified the strain by morphological observation and molecular biology methods,analyzed its growth and tolerance,and applied it to low-temperature brewing rice wine.The results showed that a low temperature tolerant yeast strain XQ2-8 was isolated and screened,which was identified as Saccharomyces cerevisiae.Compared with the control strain,strain XQ2-8 had a shorter delayed growth curve and higher biomass when reaching the stable phase at 15℃,and had better low-temperature tolerance characteristics.The strain XQ2-8 was tolerant to the growth environment and could grow normally under the conditions of ethanol volume fraction 8%vol,glucose content 60%,pH3.0 and low temperature 10℃.When rice wine was brewed using strain XQ2-8,the total ester content(60.08 mg/L)and glycerol content(2.59 g/L)of low-temperature rice wine increased by 15.6%and 22.7%,respectively,the total acid content(1.91 g/L)and total higher alcohol content(578.20 mg/L)decreased by 18.0%and 17.7%,respectively,compared with room temperature brewing,and the sensory score(89.47)increased by 11.7%.This indicates that low temperature brewing using the screened strain XQ2-8 can improve the low ester content and high higher alcohol content in rice wine and improve the quality of rice wine.