487. Studies on the origin of oxidized flavour in whole milk

Abstract

With 1·0 p.p.m. of added copper, well-defined oxidized flavours described as cardboard, oily and metallic developed in pasteurized whole milk after ·2–3 days' storage at 3° C. With 0°1 p.p.m. copper only slight and irregular off-flavours, usually described as cardboard, appeared. Partial oxidation of the ascorbic acid of the milk with H2O2did not increase its susceptibility to oxidized flavour development.Marked off-flavours were always associated with peroxide values in the milk fat of 0·2 and more (m.equiv. oxygen/kg.) determined by the ferric thiocyanate technique. With fat peroxide values of about 0·5, usually obtained after 6–7 days at 3° C. with 1·0 p.p.m. copper, the oxidized flavour was very strong and the milk usually undrinkable.