用非离子表面活性剂Tween20稳定的葵花油水包油乳状液模拟非均相食品体系,大豆磷脂脂质体模拟非均相生物体系,用水溶性的偶氮化合物AAPH热分解生成的自由基引发脂质氧化,通过硫氰酸铁法(FCT)和硫代巴比妥酸反应物法(TBARS)检测脂质的氧化进程,研究胆固醇的抗氧化活性以及VC和VE对它们抗氧化活性的影响。结果表明:不同浓度的胆固醇均具有抗氧化活性,但不同体系中其抗氧化活性并不相同。胆固醇在葵花油乳状液中具有最佳抗氧化浓度(0.02 mg/mL)。在考察2种抗氧化剂的协同作用时发现:除了用TBARS法测得3种不同浓度的胆固醇和0.001 6 mg/mL VE共同作用时显示了一定的协同抑制作用外,其余各种浓度的胆固醇与VC、VE共同作用时大部分配比是不显示协同增效作用的。

Antioxidant activities of cholesterol to lipid oxidation in sunflower oil-in-water emulsions( food model systems) stabilized by Tween 20 and soybean phosphatidylcholine liposomes( biological membrane model system) was studied. The effect of ascorbic acid and α-tocopherol on the antioxidant activity of cholesterol in different model systems was investigated. The water soluble azo-compound 2,2'-azobis( 2-amidinopropane) dihydrochloride( AAPH)could be used to generate carbon centered radicals by thermal decomposition for initiating lipids oxidation. Total antioxidant activity( TAA) was measured by ferric thiocyanate assay( FTC) and thiobarbituric acid-reactive substances( TBARS) test. The results showed that cholesterol had antioxidant activities,but was different in different systems. It was clear that cholesterol had the best antioxidant at the concentration of 0. 02 mg /mL in traditional sunflower oil-inwater emulsion. Furthermore,synergistic interactions between the cholesterol and ascorbic acid / α-tocopherol against lipid peroxidation were also investigated. It can be seen that the combination of three different concentrations cholesterol and 0. 0016 mg /mL VE had certain synergistic interactions. The other combination of cholesterol and ascorbic acid /α-tocopherol did not lead to synergistic interactions.