Effect of Lipase Activity and Aging Temperature on Formation of Ethyl Fatty Acieds in Miso

Abstract

The “koji” for manufacturing “miso” showed 15.8U/g lipase activity, and an initial “miso” freshly prepared was showed 7.0U/g. Variation of lipase activity in the course of the “miso” aging was found to be negligible. Increase of ethanol content with aging of “miso” fermentation was examined by gas chromatography. At the first stage of fermentation, no ethanol was found, while 1.5% of ethanol was found at 30°C after 15days, and 2.5% after 30 days fermentation. The rations of ethylesters of fatty acid to total fatty acids varied as follows : the ratio of about 10.5% after 15 days fermentation at 30°C was found, and rose up to about 25.7% after 30 days, while the ratio for 15 days at 20°C showed only 5.2%, and for the 30 days at 20°C, 10.4% of esters were found. By the additional lipase on the standard miso manufacturing, the content of ethylesters of fatty acids showed a remarkable increase in comparison with no lipase “miso” fermentation. The ratio of the esters to total fatty acids was found to be about 45%.