Antioxidant activity of sesame seed lignans in sunflower and flaxseed oils

Abstract

This study investigated the antioxidant activity of crude lignan extracts and purified lignans (sesamin, sesamolin, and sesamol) in sunflower and flaxseed oils. Lignan extracts were prepared from roasted sesame seed oil (LRSO) and unroasted sesame seed oil (LUSO). Additionally, the individual lignans were purified from both oils. The crude extracts and purified lignans were added at concentrations of 0.01, 0.02 and 0.03% to the oils and stored at 25 and 65°C over time and peroxide values and thiobarbituric acid values were measured. Each oil showed an increase in oxidation over time, with the samples stored at 65°C exhibiting accelerated oxidation. In general, LRSO showed higher antioxidant activity than LUSO and the antioxidant activity was similar to the antioxidant activity of butylated hydroxytoluene (0.02% BHT) in both oils when used at concentrations of 0.02 and 0.03%. Sesamol showed the highest antioxidant activity of each of the purified lignans followed by sesamin and sesamolin respectively. Crude and purified sesame lignans may have potential applications as natural antioxidants in food systems.