Volatile odorous compounds responsible for metallic, fishy taint formed in butterfat by selective oxidation

The volatile compounds produced during the selective oxidation of butterfat at 35°C induced by α‐tocopherol and cupric palmitate were isolated and their characteristic odour described as “metallic” and “fishy”. These odorous volatiles were shown to be carbonyl compounds. On chromatographic separation, the “metallic” odour was found to be associated with certain vinyl ketones, and the unpleasant “fishy” character with the class of compounds containing a 2, 4‐dienal structure. The relative yields of the various volatile compounds indicated a selective mechanism for their production.