香椿叶抗脂质过氧化物的分离及抗氧化特性

Separation and antioxidant properties of anti-lipid peroxidation fraction from Toona sinensis leaves

为寻求有应用前景的油脂抗氧化剂,分离纯化香椿叶中抗脂质过氧化物(FTAP),研究pH值、热处理及贮藏对FTAP抗氧化活性的影响及FTAP在油脂中的应用。FTAP的抗氧化活性用亚油酸过氧化法测定。采用大孔树脂分离纯化FTAP,比色法测定FTAP中的黄酮类含量。以FTAP对亚油酸过氧化抑制率反映其在不同pH值介质、热处理以及贮藏期的抗氧化性。用过氧化值评价FTAP在油脂中的抗氧化作用。结果表明,LSA-10树脂适于FTAP的分离纯化,FTAP抗脂质过氧化作用与其黄酮含量有关;FTAP在pH7、pH4时抗氧化活性较强,185℃下加热60min抗氧化性无显著变化,5℃下贮存30d抗氧化性稳定,而后逐渐降低;FTAP能抑制猪油和菜籽油的氧化,且呈量效关系,0.02%FTAP与0.02%BHT抗氧化活性相当。FTAP是具有潜力的天然抗氧化剂,可用于油脂或含油脂食品中。

In order to search for a natural antioxidant applicable for oil, fraction with anti-lipid peroxidation （FTAP） was purified from Toona sinensis leaf extracts. Effects of pH value, heat treatment and storage time on the antioxidant activity of FTAP were investigated. The suitability of FTAP as an antioxidant in lard and vegetable oil was examined. Antioxidant activity was evaluated using linoleic acid peroxidation method. Macroporous resin was used for purifying FTAP. Content of flavonoids in FTAP was assayed with spectrophotometric method. Inhibition for linoleic acid peroxidation was emplied for monitoring antioxidation of FTAP at different pH values, heat treatment and storage duration. Peroxidation value was used as a criterion to assay antioxidant activity of FTAP in oil. LSA-10 was considered as optimal macroporous resin for FTAP. Anti-lipid peroxidation of FTAP could be correlated with content of flavonoids. The antioxidant activity of FTAP was maximum at pH 7 or pH 4 and remained unchanged at 185 ℃ for 60 min. FTAP stored at 5℃ in the dark was stable for 30 days, after that the antioxidant activity was reduced. FTAP reduced lipid peroxidation significantly in lard and vegetable oil in a dose-dependent manner, and 0.02% FTAP matched 0.02% butylated hydroxytoluene（BHT）. FTAP is a potential source of natural antioxidants, and can be applied in oil or rich-oil foods.