Study Of The Antioxidative Activity And The Conversion Of Sesamolin In Lipids

Sesame lignans is a kind of natural antioxidant and an important physiological active substances in sesame seeds, which has remarkable health benefits such as the promotion of ethanol metabolism, liver detoxification function, regulation of blood fat and anti-cancer effect and so on. Sesamolin is a kind of sesame lignans, which has significant physiological functions. In this paper, based on sesamolin extracted from sesame cake as antioxidant, the antioxidant effect of sesamolin on soybean oil and change the form of sesamolin under high temperature were discussed, the antioxidant mechanism was derived, and sesamolin as natural antioxidants on the quality of soybean oil for frying was evaluated.The extraction process of sesame lignans from sesame cake were studied. The best extraction conditions were obtained by orthogonal experiment: times 1, solid-liquid ratio 1:6, temperature 50℃, time 2.5 h.Under these conditions, the extraction rate of sesame lignans was 80.55%. Combined thin layer chromatography with recrystallization purification sesamolin,make sesamolin purity is more than 97.58%. The antioxidant effect of sesamolin on soybean oil under oven high temperatures was studied. Sesamolin had good inhibition on induced lipid peroxidation of soybean oil at high temperature, the antioxidant effect was enhanced with the increasing of the amount of sesamolin; synergistic effect of citric acid, ascorbic acid and phosphoric acid on antioxidant activity of sesamolin was significant(p<0.05) under high temperature respectively, which the best of synergistic effect is phosphate; the antioxidant effect was good as that of BHT and better than that of vitamin E under same concentration; the antioxidant effect of sesamolin on high acid value soybean oil was stronger than the low acid value oil; antioxidant effect of sesamolin on soybean oil was remarkable at 120~220℃.The intermediate products of sesamolin were isolated and purified by TLC and with HPLC, MS, NMR and IR, the structure was identified. The results showed that sesamolin was converted to produce sesamol in soybean oil heating system when sesamolin added separately; Sesamolin was converted to produce sesamol, sesaminol and sesaminol isomers when used with acid synergist phosphoric.The generation of sesamol and sesaminol as strong antioxidants were the reason why sesamolin exerted an antioxidant effect.The related factors of soybean oil by frying potato were determined. The finally results: sesamolin could inhibit the increase of fried soybean oil peroxide value, anisidine value, viscosity, extend the oxidation induction time of frying oil, slow down the oxidation of polyunsaturated fatty acids, increase the ratio of(β+γ)/α, improve the utilization ratio of vitamin E bioavailability, but there was no effect on acid value change of frying. Overall, the add of sesamolin as antioxidant enhanced the oxidation stability of soybean oil for frying.