Evaluation of compounds contributing characterizing fishy flavors in fish oils

Abstract

Abstracts Vacuum steam‐deodorized fish oils oxidized under flourescent light (950 lux) at 21°C initially developed green flavors which were caused principally by t,c‐2,6‐non‐adienal, but some green‐type flavor notes were contributed by t ‐2‐hexenal and 1,c‐5‐octadien‐3‐one. Diminishment of green flavor notes resulted from the depletion of 2,6‐nonadienal and the formation of c ‐4‐heptenal (>1 ppm) which contributed oxidized, burnt flavor notes. Concomitant formation of t,c,c‐ and t,t,c ‐2,4,7‐decatrienal (>1 ppm) yielded characterizing burnt/fishy or cod liver oil‐like flavors in fish oils. Two unidentified compounds exhibiting minnow‐bait‐bucket and trout‐like odor qualities, respectively, were encountered in oxidizing fish oils. Hexanal, 2,4‐heptadienals and 2,4‐decadienals contributed general oxidized, painty flavors to fish oils.