茅台大曲中酵母的分离、鉴定及其功能初探

采用可培养方法对酱香型白酒大曲中的酵母菌进行计数和筛选,通过形态学特征、生理生化实验及酵母26S rDNA分子生物学方法鉴定酵母,并分析酵母的发酵能力和风味成分。结果表明,酱香型大曲中酵母数量为103 CFU/g;共分离鉴定6种酵母,各酵母产香能力不同,编号FBKL2.0071扣囊复膜酵母(Saccharomycopsis fibuligera)固态发酵物具有浓郁的果香味,其中以乙酸乙酯、乙酸异戊酯、苯乙醇、乙酸苯乙酯、棕榈酸乙酯含量较高。编号FBKL2.0082多株伯顿丝孢毕赤酵母(Hyphopichia burtonii)固态发酵物呈浓郁的花香味,其中以乙酸乙酯、乙酸异戊酯和苯乙醇含量较高。这两株酵母固态发酵时都能产生大量的酯类和醇类等挥发性香味物质,还有少量醛、酮、酚和烷类等物质。分离得到的酵母产酒能力不同,总体产酒能力不高。

Separation,Identification and Functional Characterization of Yeast Strains from Moutai-Flavor Daqu,a TraditionalChinese Liquor Fermentation Starter

The yeasts in Moutai-flavor Daqu were counted and screened. Through morphological characteristics, physiological and biochemical tests, yeast 26S rDNA and molecular biology, we identified and classified the isolated yeasts. In addition, the flavor compounds produced by the yeast strains in solid-state fermentation and their fermentation performance were also analyzed. The results showed that the number of yeasts in Moutai-flavor Daqu was 103 CFU/g. The yeasts isolated were classified into 6 species. All the yeast strains showed different aroma-producing abilities. Among them, the solid-state fermented products of FBKL2.0071 (Saccharomycopsis fibuligera) smelled like full-bodied fruity fragrance, and the main volatile flavor compounds included ethyl acetate, isoamyl acetate, phenylethyl alcohol, phenyl ethyl acetate and ethyl palmitate. Moreover, the solid-state fermented products of FBKL2.0082 (Hyphopichia burtonii) smelled like fullbodied flowery fragrance, and the major volatile flavor components, included ethyl acetate, isoamyl acetate and phenylethyl alcohol. These two strains not only could produce a large amount of alcohols and esters, but also produce small amounts of aldehydes and ketones. Besides, all the yeast strains showed different and poor ethyl alcohol-producing abilities.