Antioxidant activity of α- and γ-tocopherols in bulk oils and in oil-in-water emulsions

Shu Wen Huang, Edwin N. Frankel, J. Bruce German

Research output: Contribution to journalArticle

227 Scopus citations

Abstract

This study was aimed at evaluating the effectiveness of α- and γ-tocopherols in inhibiting the formation and decomposition of hydroperoxides in bulk corn oil stripped of natural tocopherols and in 10% oil-in-water emulsion systems. Whether α-tocopherol acted as an antioxidant or as a prooxidant depended on the test system, the concentration, the oxidation time, and the method used to determine lipid oxidation. On the basis of hydroperoxide formation, α-tocopherol showed maximum antioxidant activity at 100 ppm in bulk oil and at 250-500 ppm in emulsions, while γ-tocopherol showed maximum activity at 250-500 ppm in bulk oil but showed no significant difference in antioxidant activity between 250 and 1000 ppm in emulsions. α-Tocopherol had a slight, initial prooxidant effect at 250 ppm or higher concentrations in bulk oil and at 500 ppm or higher concentrations in emulsions, whereas γ-tocopherol showed no prooxidant activity in either system. However, γ-tocopherol showed less antioxidant activity than α-tocopherol at 100 ppm but higher antioxidant activity at higher concentrations in both systems. In contrast to hydroperoxide formation, the ability of both α- and γ-tocopherols in inhibiting hexanal formation improved with increased concentration and oxidation time.

Original languageEnglish (US)
Pages (from-to)2108-2114
Number of pages7
JournalJournal of Agricultural and Food Chemistry
Volume42
Issue number10
StatePublished - 1994

Keywords

  • Antioxidants
  • Antioxidation
  • Corn oil
  • Emulsion
  • Hexanal
  • Hydroperoxides
  • Interfacial oxidation
  • Mechanism
  • Tocopherols

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Food Science
  • Chemistry (miscellaneous)

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