Abstract: Process for preparing a flavoring composition suitable as a butter flavor block by subjecting triglyceride fats, fatty acids or fatty acid derivatives to oxidizing conditions, comprising:(a) admixing an anti-oxidant to triglyceride fats, fatty acids or fatty acid derivatives at least to a concentration which is sufficient to increase the induction period of the fat by a factor of 1.5,(b) heating the mixture for 0.5 hours-1 week at 50.degree.-150.degree. C. under access of atmospheric oxygen and in the presence of water,under the condition that the triglyceride fats, fatty acids or fatty acid derivatives contain at least one poly-unsaturated fatty acid with an omega-3 non-conjugatable double bond system in an amount of >0.01 wt. %. Such fatty acids or derivatives of fatty acid are preferably obtained by partially hydrogenating a natural vegetable glyceride fat.