Activity of antioxidants in solution and in irradiated heterogeneous system

Abstract

AbstractThe efficiency of some common antioxidants, α‐tocopherol, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), was studied relative to β‐carotene in a homogeneous solution and in a model system of an irradiated solid food. Relative reactivities in homogeneous solution covered a range of three orders of magnitude, α‐tocopherol being the best and BHT the poorest antioxidant of the three. In irradiated systems consisting of oleic acid coated on a solid support (egg white), the range of reactivities was much narrower within one order of magnitude. In solution, there was a parallelism of the relative reactivities with oxidizing alkoxyl radicals derived from oleic acid hydroperoxides andtert‐butyl hydroperoxide. On the solid support the relative reactivities of α‐tocopherol and BHA with oleic acid radiation‐induced oxidizing radicals were reversed, BHA appearing the best. Efficient antioxidants do not retain their great antioxidant activity in comparison with the moderate ones on transition from a homogeneous solution to a heterogeneous system. Relative efficiencies of antioxidants do not critically depend on the nature of oxidizing radicals in heterogeneous media.