Japanese sake production involves three processes: rice koji fermentation, seed mash fermentation, and main mash fermentation. Traditional seed mash (kimoto) production utilizes natural lactic acid produced by lactic acid bacteria for pure cultures of only sake yeast, preventing the growth of wild yeast and other unwanted bacteria. Recently, because kimoto production requires substantial time and labor, sake yeast mass-cultured in usual liquid medium has been used as a seed mash alternative. Sake quality is highly similar to that of kimoto, suggesting that they share similar component profiles. However, comparative component analyses of sake brewed with kimoto and sake brewed with cultured yeast are lacking. In this study, a time-course analysis of hydrophilic compounds in the main mash brewed with kimoto and with cultured yeast as well as a sensory evaluation of the products were performed. As a result, differences in various compounds and in umami taste level between sake brewed with kimoto and cultured yeast were detected. This is the first comparative analysis of changes in the component profile during sake main mash brewing using kimoto seed mash and cultured sake yeast; our results clarify the effects of kimoto seed mash on main mash brewing and sake quality.

日本清酒的生产涉及三个过程：米曲发酵，种子糖化fermentation发酵和主要糖化fermentation发酵。传统的种子（kimoto）生产利用乳酸菌产生的天然乳酸仅用于清酒酵母的纯培养，从而防止了野生酵母和其他有害细菌的生长。近来，由于kimoto的生产需要大量的时间和劳力，因此在常规液体培养基中大量培养的清酒酵母已被用作种子浆的替代品。清酒的品质与kimoto的品质非常相似，表明它们具有相似的成分特征。但是，用kimoto酿造的清酒的比较成分分析缺乏用培养的酵母酿造的清酒。在这项研究中，进行了时程分析，分析了用木本和培养的酵母酿造的主麦芽中的亲水性化合物，并对产品进行了感官评估。结果，检测了用kimoto酿造的清酒和培养的酵母之间的各种化合物和鲜味水平的差异。这是首次使用木本籽泥和培养的清酒酵母酿造清酒主糖浆过程中成分变化的比较分析。我们的结果阐明了Kimoto籽糖浆对主要糖浆酿造和清酒质量的影响。