Premium
Antioxidant effects of d‐tocopherols at different concentrations in oils during microwave heating
Author(s) -
Yoshida Hiromi,
Kajimoto Goro,
Emura Shiuji
Publication year - 1993
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02543025
Subject(s) - tocopherol , chemistry , antioxidant , chromatography , microwave oven , peroxide , oxidative phosphorylation , substrate (aquarium) , vitamin e , peroxide value , organic chemistry , microwave , biochemistry , physics , oceanography , quantum mechanics , geology
The effects of d‐tocopherols at different concentrations (50 to 1000 ppm) on the oxidative stability of ethyl linoleate and tocopherol‐stripped oils were investigated under microwave heating conditions. Purified substrate oils were prepared by aluminum oxide column chromatography. After the addition of tocopherols (α‐, β‐, γ‐ or δ‐) to the oils, peroxide, carbonyl and p ‐anisidine values were measured in the samples after heating in a microwave oven. Further, the residual amount of tocopherol homologues in the oils after heating was determined by high‐performance liquid chromatography for evaluation of their effects at different concentrations on oxidative deterioration. Microwave heating resulted in some acceleration in the oxidation of the purified substrate oils. Optimum concentrations of tocopherols required to increase oxidative stability were 100 ppm for α‐, 150–200 ppm for β‐ or γ‐ and 500 ppm for δ‐tocopherol, respectively. The antioxidant effect of tocopherols decreased in the order α>β ≒ γ>δ at each level, in all substrates. Therefore, α‐tocopherol was consumed first, followed by β‐ or γ‐tocopherol, and δ‐tocopherol was consumed more slowly. The tocopherols had no further significant antioxidant activity ( P >0.05) at concentrations higher than 500 ppm.