鲜食水稻籽粒成熟过程中多糖组成及抗氧化活性分析

以不同成熟时期的鲜食水稻籽粒为原料,采用超声—微波协同萃取法提取多糖,同时利用HPLC法分析了多糖的组成,并通过体外抗氧化试验测定其抗氧化活性。试验结果表明,乳熟后期,鲜食水稻中多糖含量最高,达46.89 mg/g;此时的多糖组分主要为甘露糖、鼠李糖、葡萄糖醛酸、半乳糖醛酸、葡萄糖、半乳糖、木糖、阿拉伯糖和岩藻糖等,而完熟期鲜食水稻的多糖组分中并未检出甘露糖和岩藻糖;通过对不同时期鲜食水稻中多糖的抗氧化能力研究发现,乳熟后期的鲜食水稻籽粒中,多糖对ABTS+自由基、DPPH自由基、羟基自由基、超氧阴离子清除率分别为86.18%,56.81%,75.62%,41.69%,均强于其他时期。

Analysis of composition and antioxidant activity of polysaccharides in immature rice during seed development

In order to determine the change rule of polysaccharides content in fresh rice grains at different mature stages, the polysaccharides were extracted from fresh rice grains at different mature stages by ultrasonic-microwave synergistic extraction method. The composition of polysaccharides was analyzed by HPLC, and the antioxidant activity of polysaccharides was determined by antioxidant test in vitro. The results showed that the content of polysaccharides in fresh rice was the highest at the stage of late milk, up to 46.89 mg/g. Mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose, arabinose and fucose were the main components of polysaccharides at this stage, while mannose and fucose were not detected in polysaccharides of fresh rice at full ripening stage. The scavenging effects of polysaccharides on ABTS⁺, DPPH free radical, hydroxyl free radical and superoxide anion in fresh rice grains at later milk stage were 86.18%, 56.81%, 75.62% and 41.69% respectively, which were higher than those at other stages. This study has practical significance for the comprehensive utilization of fresh rice, and can provide reference for the development and utilization of fresh rice in functional food.