[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 commercial scale for shochu production tests was carried out using Saccharomyces cerevisiae "Heisei Miyazaki Yeast" (MF062), which was selected for its superior ability in terms of alcohol fermentation and aromatic ingredient generation among 272 wild yeasts isolated from the shochu mash of shochu breweries. Alcohol yield and general components in shochu production using MF062 were the same as those in industrial yeasts like "Miyazaki Yeast" (MK021) in seven shochu breweries, namely, 3 sweet potato shochu and 4 barley shochu breweries. Five series of sashimoto were also performed with constant high alcohol yield. Shochu produced using MF062 was awarded high scores in the sensory tests. Investigation of the relations between sensory tests and higher alcohol (n-propyl alcohol(P), i-butyl alcohol(B), and i-amyl alcohol(A)) in shochu showed that shochu with smaller A/P and A/(P+B) received better evaluations. Shochu made using MF062 received high evaluations because MF062 could produce a suitable ratio of higher alcohol. From the above results, it was confirmed that MF062 could be used for commercial production of shochu just the same as with commercial strains which have excellent brewing properties.

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In this study, we attempted to isolate yeast by an enriched culture method from 124 flower samples collected from various regions of Japan. Forty-seven isolates which vigorously fermented and did not form a film on the YM medium containing 10% glucose were obtained. On the basis of the analyses of filtrates of sake mashes which were products of froth forming tests, only 3 isolates--TP1, DR3, and KM8-3 strains--produced good aromas although 30 isolates produced alcohol equivalent to sake yeast kyokai No. 9. The small-scale sake brewing tests with TP1, DR3, and KM8-3 strains revealed that TP1 had equivalent fermentation ability to sake yeast kyokai No. 9. On the basis of molecular evolutionary analyses based on DNA sequences of 26S rDNA-D1/D2 and ITS regions, TP1 was identified as Saccharomyces cerevisiae. The sake produced by TP1 showed particular compositions of aroma compounds and organic acids. Especially, high ethyl caproate concentration, high citric acid concentration, low succinic acid concentration, high isoamyl alcohol/ isobutyl alcohol ratio, and high malic acid/ succinic acid ratio were shown. The TP1 strain was deemed a useful yeast for sake production because it did not form foam on sake mash and was able to reduce TTC. It is expected that the TP1 will be used for sake production as a useful yeast which is able to produce a unique flavor.

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