糙米体外消化过程中酚类物质含量及抗氧化活性

以糙米为对象，围绕其体外消化过程酚类物质及抗氧化活性变化开展研究。结果表明：粳型糙米中总酚含量显著高于籼型糙米（约1.5?倍）。胃和小肠消化显著促进粳型和籼型糙米中酚类物质释放（P＜0.05），其释放量（以没食子酸当量计）最高值为460.9?mg/100?g和401.1?mg/100?g，粳型糙米中酚类物质释放量显著高于籼型糙米；两者酚类物质释放量随消化时间变化趋势均符合幂函数模型。铁离子还原/抗氧化能力（ferric-reducing antioxidant power，FRAP）和氧自由基清除能力（oxygen radical absorbance capacity，ORAC）实验表明糙米体外消化过程中释放的酚类物质具有良好抗氧化能力，粳型和籼型糙米消化液FRAP值（以Trolox当量计）最大为10.76、8.44?μmol/g，ORAC值（以Trolox当量计）最大为6.82?μmol/g和6.23?μmol/g。

Changes in Polyphenols Content and Antioxidant Activity during in Vitro Digestion of Brown Rice

In this research, changes in polyphenols content and antioxidant capacity during in vitro digestion of brown rice were studied. The total phenolic content in brown Japonica rice was significantly higher than that in brown Indica rice (about 1.5 times). During simulated in vitro gastrointestinal digestion, the release of polyphenols (calculated as gallic acid equivalent) was increased significantly for both rice varieties (P < 0.05), with the maximum value (460.9 mg/100 g) of Japonica rice being significantly higher than that (401.1 mg/100 g) of Indica rice. The release of polyphenols versus digestion time was fitted to a power function. The results of ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) showed that the polyphenols released during in vitro digestion of brown Japonica and Indica rice possessed potent antioxidant activity. Both FRAP and ORAC were calculated as trolox equivalent. The maximum FRAP values of digested Japonica and Indica rice were 10.76 and 8.44 μmol/g, and the maximum ORAC values were 6.82 and 6.23 μmol/g, respectively.