Studies on awamori brewing using a mixture of koji made for different time : (II) Changes in fatty acid in process of awamori brewing (Department of Bioscience and Biotechnology)

泡盛酒質は米麹の品質によって著しく影響される。米麹脂質成分の脂肪酸は酒精発酵における酵母のエステル生成に関わる重要な成分である。本研究では,泡盛醸造工程における脂肪酸の変動を通常麹と製麹時間差麹を用いた発酵において調べ,次の様な結果を得た。黒麹菌(Asp.awamori G-122)を用いて調製された米麹の脂質画分には5種類の脂肪酸が検出され,リノール酸とパルミチン酸が主成分であった。米麹中の全脂肪酸は製麹時間が40時間までは増大したが,その後徐々に減少した。一方,遊離脂肪酸は製麹工程で初発含量の約24%が減少した。発酵液中の全脂肪酸は発酵初期に増加し,後期には一定値を示した(1100-1160mg/100g, 乾燥掬麺)。遊離脂肪酸の中でリノール酸は発酵4日目まで著しく減少し,その後一定値を推移した。通常麹と製麹時間差麹を用いた発酵における全脂肪酸および遊離脂肪酸量には著しい差異は認められなかった。The quality of awamori beverage is greatly affected by the quality of rice-koji prepared by cultivating black-koji mold on steamed-broken rice. Fatty acids in lipid of rice-koji are very important components for ester formation by brewer's yeast in alcohol fermentation. In this study, changes in fatty acid concentration in process of awamori brewing were investigated by use of normal-koji, only 42 hr-making koji, and mixture-koji which were combined 20hr-making koji with 42 hr-making koji as a substrate and the following results were obtained. Five kinds of fatty acid were detected in the lipid of rice-koji prepared with Asp. awamori G-122,of which main compounds were linoleic and palmitic acids. Total-fatty acid of rice-koji increased in course of koji making time up to 40 hr and gradually decreased in the later stages. On the contrary, free-fatty acid of rice-koji reduced about 24% of initial amount during koji making. For the quantity of fatty acid in moromi-mash, total-fatty acid trended to increase in early stages of fermentation and reached a plateau in the range from 1100 to 1160mg per 100g of dried-koji. Only linoleic acid of free-fatty acid significantly decreased in 4 days of fermentation and retained nearly constant values in later stages. There was no significant difference between normal-koji and mixture-koji in the level of total-and free-fatty acid concentrations during fermentation