Accumulatioh of Diglycerides and Monog1ycerides and Decrease of Unsaturated Free Fatty Acids in Miso

Abstract

Lipid contents and free fatty acid composition of lipid components of miso were analyzed. Lipid contents were 3.8 to 6.9% in rice miso, and 7.6 to 8.5% in soybean miso(weight/wet weight of miso). Soybean miso samples showed the highest content of free fatty acids(36 to 58% of total lipids). A few miso samples accumulated 1, 3-diglycerides or monoglycerides which were intermediates of the hydrolysis of triglycerides. Fatty acid compositions of most of miso were found similar to that of soybean, but in a few soybean miso the linolic acid content of free fatty acid fraction was found less than 35%, unlike in shoyu oil and tamari shoyu oil. In order to investigate the reason for the soybean miso smaller content of linolic acid of free fatty acids in soybean miso, warmed brewing of was carried out. In the fermentation of soybean miso, no progress of lipid hydrolysis was observed in the first two months. Free fatty acid fraction increased and linolic acid of free fatty acid fraction decreased after the two-month period.