Photooxidation of unsaturated oils: Effects of singlet oxygen quenchers

Abstract

Abstract The photooxidative deterioration of unsaturated food oils by near UV and visible light was found to be retarded by nickel (II) chelates well known to quench singlet oxygen ( 1 O 2 ). The rates of hydroperoxide formation during light exposure were unaffected by efficient peroxy radical scavengers such as hindered phenols. α‐Tocopherol (vitamin E) underwent a relatively rapid oxidation itself when exposed to 1 O 2 in oil solutions, despite being able to deactivate 1 O 2 quite efficiently. From a comparison of the rates of scavenging by stabilizers and attack on allyl groups, 1 O 2 initiated deterioration is appreciably more difficult to retard than peroxy radical processes.