Journal of the American Oil Chemists’ Society

, Volume 70, Issue 10, pp 989–995

Antioxidant effects of d-tocopherols at different concentrations in oils during microwave heating

  • Hiromi Yoshida
  • Goro Kajimoto
  • Shiuji Emura
Article

DOI: 10.1007/BF02543025

Cite this article as:
Yoshida, H., Kajimoto, G. & Emura, S. J Am Oil Chem Soc (1993) 70: 989. doi:10.1007/BF02543025

Abstract

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 andp-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.

Key words

Anisidine valueantioxidant effectscarbonyl valuehigh-performance liquid chromatographymicrowave heatingperoxide valuepurified vegetable oilstocopherol homologues

Copyright information

© AOCS Press 1993

Authors and Affiliations

  • Hiromi Yoshida
    • 1
  • Goro Kajimoto
    • 1
  • Shiuji Emura
    • 1
  1. 1.Department of NutritionKobe-Gakuin UniversityKobeJapan