Abstract
Antioxidative action of methionine in the systems containing linoleic acid (LA system), linoleic acid hydroperoxide (LAHPO system) and secondary degradation product of linoleic acid (LASP system) was studied and the following results were obtained.
1) Methionine inhibited the increase of POV in LA system and decreased the POV in LAHPO system, remarkably.
2) Amount of free methionine in LAHPO system was decreased during the reaction, and the decreases of POV and of methionine were highly corrected. Furthermore, it was confirmed that methionine in LAHPO system was transformed into methionine sulfoxide in the course of the reaction.
3) Methionine increased the acidity of the LAHPO system, while no significant difference was observed in hydroxyl group content in all the systems with or without methionine.
4) The presence of methionine in both LA and LAHPO systems did not increase the oxygen absorption of the systems.
5) From these results, the following mechanism on antioxidative action of methionine is proposed:
