SummaryThe oxypolymerization of unsaturated fat in the presence of protein and amino acid was studied to determine whether the active carbonyl‐amine‐browning reaction is a dominant mechanism for the formation of brown‐colored polymers. A highly reactive system of menhaden oil‐aqueous egg albumin emulsion was studied in greatest detail. Three types of studies: activation energy of formation of brown color, inhibition analysis of the mechanism leading to formation of brown color, and measures of amino acid reaction in the oxidizing unsaturated fats, all gave evidence that active carbonyl‐amine browning was not a dominant mechanism.