D-Amino acids, which are non-structural amino acids for proteins, are present only in small amounts in vivo. Nevertheless, some D-amino acids produce a strong taste for sake. Particularly, sake made by Kimoto, a Japanese traditional brewing method, contains high D-amino acid concentrations because lactic acid bacteria grown in Kimoto mash produce D-amino acid during fermentation. D-alanine in sake improved the Umami taste of sake. For production of a good tasting sake, high concentrations of D-amino acids must be produced during fermentation by lactic acid bacteria. For this study, we isolated lactic acid bacteria that have a high potential for producing D-amino acid. We did so rapidly with a D-amino acid assay method using D-amino acid oxidase. The Lactobacillus sakei ZH-2 strain was isolated from vegetable plant sources. The strain supported a D-amino acid conversion ratio of approximately 16% in a glucose（1.0 %）–peptone（1 %）–yeast extract（GYP）medium containing 3μg/L pantothenate for 24 hr. The crude enzyme extracted from the ZH-2 strain was converted from L-alanine, L-serine, or L-glutamic acid to D-amino acid formation. Results suggest that the strain was able to produce D-amino acid.

Red koji, a traditional food or medicine for centuries in East Asia including China, the Ryukyu Islands, Taiwan, and Japan, is made by fermenting steamed rice with red fungus Monascus. Previous studies showed the anti-inflammatory effect of M. purpureus. In this study, the anti-inflammatory substances of M. purpureus and M. pilosus were investigated using mouse macrophage RAW264.7 cells. The strongest anti-inflammatory lipid fraction of M. purpureus was purified and structurally determined to be ergosterol by trimethylsilylation followed by GC-MS. The same ergosterol was also found in M. pilosus. using trimethylsilylation followed by GC-MS and NMR. These results indicate that red koji manufactured using M. purpureus and M. pilosus contains ergosterol, which exhibits a strong anti-inflammatory effect.

In the production of sake, the enzyme digestibility of the steamed rice grains is a critical factor to realize a good quality of sake and to utilize rice grains efficiently. The retrogradation of rice starch in the steamed rice grains proceeds during sake making, and the enzyme digestibility of the steamed rice grains decreases significantly. However, the influencing factors of the retrogradation of starch in the steamed rice grains have not been elucidated clearly. In the present study, the relationships between the moisture content in steamed rice grains, the retrogradation of rice starch, and the enzyme digestibility were examined to clarify the influencing factors of the retrogradation of the starch. Steamed rice grains with a high moisture content showed a faster retrogradation of starch and lower enzyme digestibility than those with a low moisture content after storage in a plastic bag. Moreover, when the moisture content in the steamed rice grains decreased during storing under lower humidity conditions, the rate of the retrogradation and the decrease of the enzyme digestibility were slight. The present results indicated that the moisture contents of the steamed rice grains have a significant influence on rice starch retrogradation and enzyme digestibility after storing in conditions such as the cooling process of steamed rice grains in Daiginjyo sake production.