Evolution of lipids during koji fermentation and the effect of lipase supplementation on the sensory properties
of soy sauce were investigated. Results showed that total lipids of the koji samples were in the
range of 16–21%. The extracted lipid of initial koji consisted mainly of triacylglycerols (TAGs, >98%),
followed by phospholipids (PLs), diglycerides (DAGs), monoacylglycerols (MAGs) and free fatty acids
(FFAs). As the fermentation proceeded, peroxide value of the lipids decreased while carbonyl value
increased (p < 0.05). Linoleic acid was utilised fastest according to the fatty acid composition of total lipids,
and preferential degradation of PLs to liberate FFAs was also observed. Moreover, phospholipase supplementation
had significant influence on the sensory characteristics of soy sauce, especially enhanced
(p < 0.05) scores for the umami and kokumi taste attributes. All these results indicated that the control
of PLs utilisation during fermentation was a potential method to improve soy sauce’s characteristic taste.