Formation of the intense flavor compoundtrans‐4,5‐epoxy‐(E)‐2‐decenal in thermally treated fats

Thermal degradation of several possible precursors of the intense flavor compound trans ‐4,5‐epoxy‐( E )‐2‐decenal in model experiments revealed that the odorant is formed in significant yields from 13‐hydroperoxy‐9,11‐octadecadienoic acid (13‐HPOD) and 9‐hydroperoxy‐10,12‐octadecadienoic acid (9‐HPOD). Of these hydroperoxides, arising in equal amounts during autoxidation of linoleic acid, the 9‐HPOD was established as the more effective precursor. The key intermediates in the generation of the epoxyaldehyde were found to be 2,4‐decadienal, arising from 9‐HPOD, and 12,13‐epoxy‐9‐hydroperoxy‐10‐octadecenoic acid, a degradation product of 13‐HPOD. Isolation and characterization of the precursors from a baking margarine confirmed glycerine‐bound 9‐ and 13‐HPOD as the intermediates in the formation of the epoxyaldehyde during heating of fats that contain linoleic acid.