Effects of tocopherols and their mixtures on the oxidative stability of olive oil and linseed oil under heating

The tested tocopherols (γ,δ,α) showed antioxidative activity at all levels of addition to the monounsaturated olive oil, the effects increased as a function of concentrations (maximum: +287% with 800 mg γ-tocopherol/100 g oil compared to the control oil). In the highly unsaturated linseed oil, which contains 58 mg/100 g initial concentration of γ-tocopherol, γ-tocopherol showed antioxidative behavior up to the addition of 100 mg/ 100 g oil. Additions of more than the 100 mg/100 g affected the oil, resulting in a faster oxidation. Mixtures of γ/δ-tocopherols in olive oil were found to protect more efficiently than both vitamins when added separately α-tocopherol reduced effects of other tocopherols in both plant oils. The stabilizing effect of added tocopherols and their mixtures (100 mg/100 g oil each) in olive oil are γ/δ-T>γ-T>δ-T>γ/α-T>δ/α-T>α-T and in linseed oil γ-T>γ/δ-T>δ-T>γ/α-T>α-T>α/δ-T.