[in Japanese]

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[in Japanese]

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[in Japanese]

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This study aimed to establish quantitative methods for analyzing the maturation and antioxidant activity of sake by chemiluminescence. For this purpose, we focused our attention on chemiluminescence and identified the suitability of each index for use. The maturation indexes included X photon emission and NaCIO photon emission. The antioxidation indexes included Y photon emission, MPEC (Atto Co., Ltd.), and Radical Catch (RC, Aloka Co., Ltd.).
Photon emission could be measured by a mobile photon counter machine, and there was stability in the NaClO photon emission, Y photon emission, MPEC, and RC. However, there was little reactivity and no stability in the X photon emission. In the sake stored at 50°C during a period of up to six days, NaClO photon emission and MPEC had a high correlation between chemical indexes (3-DG and DPPH). Neither the Y photon emission nor RC showed a clear correlation between chemical indexes. From the present results, NaClO photon emission and MPEC would appear to be the most suitable methods for the maturation and antioxidant activity evaluation of sake. Furthermore, we clarified the need to identify the pH of sake and correct NaClO photon emission. MPEC was able to measure the quantity of gallic acid and tannic acid, antioxidant ingredients.

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We carried out test brewing with two types of yeast to compare changes in visible cell counts and several components in moromi mash during fermentation. S. cerevisiae Hiroshima ginjo kobo(HG) and Kumamoto kobo KA-4(KA-4) were respectively used as an ethyl capronate high-producing yeast and an ordinary yeast, which has good fermentation ability, for high quality sake. Visible cell counts of HG were lower than those of KA-4 throughout the fermentation period. Percentages of visible cell counts of HG to total yeasts began to decrease at the early stage of fermentation and were approximately 10-60% at the middle stage of fermentation. As the ratio of the addition of HG to KA-4 to moromi mash for starter culture was higher, the alcohol content and acidity were lower and the baumè deceasing rate was slower during fermentation. In addition, ethyl capronate and capronate concentrations were higher, but ethyl acetate and isoamyl acetate concentrations were lower on flavor components throughout the fermentation period. Malate and succinate concentrations decreased in moromi mash on organic acids with increasing ratios of the addition of HG to KA-4 to moromi mash.

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