New insights into the antioxidant activity of Trolox in o/w emulsions

The antioxidant activity of Trolox was investigated in emulsions containing different emulsifiers, and decreased in the order Brij 58 > CTAB > SDS. Two degradation products were isolated and identified as Trolox quinone and a keto-derivative. In addition to the stability of Trolox, the effects of the degradation products on lipid oxidation were investigated. In emulsions with SDS, the quinone and the keto-derivative contributed to the overall pro-oxidant effect of Trolox, whereas they had no effect in emulsions containing CTAB or Brij 58. It was concluded that the microenvironment at the o/w interface has a marked influence on the antioxidant and pro-oxidant effects of Trolox and its degradation products via molecular interactions and by affecting its molecular mobility. (C) 2010 Published by Elsevier Ltd.