Abstract

"Sake Yeast Beer” is a beer style characterized by the unique flavor of the sake yeast strain; however, it cannot ferment wort because of the low assimilation ability of maltose. Herein, a sake yeast strain was bred for improved maltose assimilation ability and an original sake yeast strain optimized for a beer brewing environment was developed. The mutant sake yeast strains produced large amounts of isoamyl acetate (3-methylbutyl acetate) and ethyl caproate (ethyl hexanoate) responsible for the ginjo-aroma of sake. A detailed analysis of the volatile components in a small-scale beer brewing test revealed that the beer brewed with BMK3, one of the mutant strains, was composed of many volatile components generated by yeast, such as esters, alcohols, and fatty acids, in comparison to the beer fermented with a general brewer’s yeast. Moreover, in a full-scale beer brewing test using BMK3, the beer was composed of isoamyl acetate and ethyl caproate at 2.3 and 6.7 ppm, respectively. On the sensory evaluation of two beers fermented with BMK3 and a general brewer’s yeast, the beer brewed with BMK3 had the unique characteristics of “ginjo-aroma like fruit,” remaining “sweetness,” and a “rich body but crisp finish.”

摘要

“清酒酵母啤酒”是一种以清酒酵母菌株独特风味为特征的啤酒风格，但由于麦芽糖同化能力低，无法发酵麦芽汁。为此，培育了一种清酒酵母菌株，以提高麦芽糖同化能力和开发了针对啤酒酿造环境优化的原始清酒酵母菌株。突变的清酒酵母菌株产生大量的乙酸异戊酯（乙酸3-甲基丁酯）和己酸乙酯（己酸乙酯），从而产生了吟酿。- 清酒的香气。通过对小规模啤酒酿造试验中挥发性成分的详细分析发现，用突变菌株之一BMK3酿造的啤酒中含有多种由酵母产生的酯类、醇类、脂肪酸等挥发性成分。与用一般啤酒酵母发酵的啤酒相比。此外，在使用 BMK3 的全面啤酒酿造测试中，啤酒中乙酸异戊酯和己酸乙酯的含量分别为 2.3 ppm 和 6.7 ppm。对用BMK3和普通啤酒酵母发酵的两种啤酒进行感官评价，用BMK3酿造的啤酒具有“果香般的吟酿香气”、保留“甜味”和“酒体浓郁但余味清脆”的独特特征。