Characterization of Off-Flavors by Aroma Extract Dilution Analysis

Aroma extract dilution analysis was used to identify those odorants which contribute significantly to the warmed-over flavor (WOF) of boiled beef, as well as to the light-induced off-flavors of soybean oil and milkfat. WOF was due to an increase of the odorants formed by lipid peroxidation, in particular hexanal and trans-4,5-epoxy-(E)-2-decenal. The light-induced off-flavors of soybean oil and milkfat were mainly caused by 3-methylnonane-2,4-dione, which was formed by photosensitized oxidation of furanoid fatty acids, whose concentration levels in these fats were in the range of 0.01 to 0.05 per cent.