[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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A novel approach to isolate a low pyruvate-producing sake yeast by using mitochondrial transport as the breeding target has recently been proved successful. Using this approach, we have bred a new sake yeast strain which produces low amounts of pyruvate during sake brewing on a laboratory scale. In this study, we brewed low alcohol sake with this new strain and analyzed the pyruvate concentration, organic acid concentrations, and brewing characteristics. Results showed that this strain produces a low amount of pyruvate during the brewing of low alcohol sake on a laboratory small scale relative to its parent strain K7（Kyokai No. 7）. This strain additionally produced a low amount of pyruvate during the brewing of low alcohol sake on a middle pilot scale relative to its parent strain K7, and this strain had a desirable brewing competence, with no observable deterioration relative to its parent strain K7. The low alcohol sake brewed with TCR7 was evaluated by trained panels to have a favorable tart taste. A principal component analysis of the organic acids of low alcohol sake revealed that the first principal component, which correlates with 2 or 3 carbonic acids, of sake brewed with TCR7 is lower than that of sake brewed with K7. These results put this strain as a promising and practical sake yeast strain appropriate for the brewing of low alcohol sake at the factory level.

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