In this study, a Gifu University yeast, strain GY115, was bred for ale beer brewing and its fermentation characteristics were evaluated. Strain GY115, which belongs to the sake yeast group, had high growth and fermentation abilities for maltose. In addition, strain GY115-a3M, a mutant strain adapted to high maltose conditions, demonstrated excellent fermentation ability even in a wort medium with added hops. In the early stages, its fermentation ability was significantly higher than that of the ale yeast strain US-05. Furthermore, in an ale beer brewing test using wort, strain GY115-a3M was shown to brew an ale beer with a fruity flavor, similar to that of Japanese sake. From these results, we propose that strain GY115-a3M has a high potential for brewing both ale beer and Japanese sake.

Samples of six types of narezushi (nine products), a traditional Japanese fermented fish food, were analyzed for pH, salt, free amino acids and organic acids. Taste was analyzed using a taste sensor. The pH of narezushi ranged from 3.7 to 4.5. The salt content ranged from 1.3 g to 4.6 g/100 g. The free amino acids varied depending on the types of narezushi. The ingredients added in each type are assumed to be one of the factors affecting the difference. The organic acids also varied with the narezushi types. The taste sensor analysis showed that the taste characteristics of funazushi differed from those of the other narezushi examined in this study. The taste characteristics were similar among the three ayu-narezushi products and among the two nezushi and one kaburazushi products. This study provides basic data on the chemical compositions and taste of narezushi, including comparisons between and among the different types.

In this study, we examined the effects on microorganisms of Ishizuchi-kurocha depending on the production container, the position during fermentation, and the production lot. Ishizuchi-kurocha is produced in Ehime Prefecture, Japan, and produced by tea leaves through two-step fermentation: aerobic fermentation followed by anaerobic fermentation. In the traditional production method, wooden barrels were used for the anaerobic second fermentation, but now plastic buckets are used. Microorganisms were isolated from the inner and outer layers of tea leaves at each fermentation stage, and the microbial community structure was analyzed using a nextgeneration sequencer for tea produced in multiple lots in the same year using plastic buckets or wooden barrels during the second fermentation. Regardless of the production conditions, molds of the genus Aspergillus were dominant in the primary fermentation and lactic acid bacteria were dominant in the secondary fermentation, suggesting normal fermentation progression. On the other hand, there were differences in yeast species depending on the production container used for secondary fermentation. Although differences in manufacturing containers do not affect the dominant species, they are thought to affect the growth and type of yeast, which may affect the flavor of Ishizuchi-kurocha. In addition, the influence of the position during fermentation was also confirmed, as lactic acid bacteria were detected inside the tea leaves after primary fermentation. The findings obtained from this study are thought to lead to the application of the traditional manufacturing method and stabilization of Ishizuchi-kurocha production.