Inhibition of Formation of Conjugated Dienes in Linseed Oil

Oxidation of fats and oils reduces the nutritional value of food and causes various health problems. The addition of antioxidants prevents the oxidation of fats in the food. The antioxidant activity of antioxidants represents the ability to inhibit the process of oxidation. The antioxidant activity of herbal extracts has usually been assessed in a linoleic acid emulsion system. The aim of the present study was to evaluate inhibition of conjugated diene formation in Latvian linseed oil. Ethanol extract of the calyx of Hibiscus sabdariffa L., vanillin, α-tocopherol and 2,6-di-tert-butyl-4-methylphenol as additives were compared for their antioxidative activity. The samples of linseed oil with additives were incubated for 24 h at 60 °C and then analysed using UV spectrophotometry (λ = 234 nm). The antioxidant activity of additives was characterised by the percentage of formation of conjugated dienes. The ability of additives to inhibit oxidation in linseed oil decreases as follows: vanillin, 2,6-di-tert-butyl-4-methylphenol and α-tocopherol. Our results indicate that linseed oil can be used to test antioxidative activity of substances.