不同颜色糙米的酚类物质组成及抗氧化活性分析

Phenolic compounds and antioxidant activity of brown rice in different color of bran

以8种不同颜色的糙米为研究对象,分别提取糙米中游离型和结合型酚,并对提取物中的酚类物质(总酚、总黄酮、总花青素、总原花青素、总酚酸)的含量以及ABTS自由基(ABTS+)清除能力与铁离子还原能力进行了研究,比较了不同颜色间糙米的酚类物质和抗氧化活性的差异以及两者与颜色参数间的相关性。研究结果表明:糙米的抗氧化活性与结合型、游离型的酚类物质含量呈正相关(P<0.05);结合型酚类物质的含量和抗氧化活性与糙米颜色均无显著相关(P>0.05);游离型酚类物质含量、组成以及抗氧化活性与糙米颜色有相关,糙米颜色越深酚含量越高、抗氧化活性越强,且原花青素主要存在于红色糙米或部分黑色糙米中。

Eight different color brown rice were used to extract the free and compound form of phenolics. The content of phenolic compounds,including total phenolic,total flavonoids,total anthocyanins,total proanthocyanidin,total phenolic acids,and the capacity of ABTS＋radical scavenging and ferric ion reduction were studied. We also compared the difference of phenolic compounds and antioxidant activity in different color brown rice as well as the correlation between color parameters,phenolic content and antioxidant activity. Those results shown that antioxidant activity and content of phenols in both free and bound forms were positively correlated（ P〈0. 05）; the compound form of phenols and antioxidant activity were unrelated with rice bran color（ P〉0. 05）; while the free phenolic content and composition,antioxidant activity were related with rice bran color. The more dark color of the rice,the more phenols,and the stronger antioxidant activity. Proanthocyanidin was mainly existed in red rice and some black rice varieties.