糙米、米糠和精米在体外模拟消化过程中抗氧化活性的变化规律

摘要

采用体外模拟消化法对糙米、米糠和精米进行模拟胃肠消化实验,采用Folin-ciocalteu法、氯化铝-亚硝酸钠法和氧自由基吸收能力法(ORAC)分别测定模拟消化过程中抗氧化活性物质(以多酚表示)、黄酮和抗氧化活性的变化规律.结果显示:与模拟胃消化0h相比,模拟胃消化和模拟胃肠消化过程中糙米、米糠和精米的最大多酚释放量分别为其3.499、1.753和6.595倍和4.704、1.828、9.113倍,最大黄酮释放量分别为其的1.522、5.961和1.653倍和3.359、5.958、3.242倍,最大ORAC值分别为其3.459、4.849和12.93倍和5.659、5.112、19.65倍.表明谷物结合多酚在胃肠消化过程中,由于胃酸水解和胃肠蛋白酶酶解等消化作用使多酚由结合态转变为游离态,因而谷物结合多酚可以在胃肠道消化吸收.%The simulated gastrointestinal digestive experiments were studied by the method of simulated digestion in vitro for brown rice,rice bran and polished rice,Regularity of antioxidant active substances (expressed in polyphenols) and flavonoids,as well as antioxidant activity were determined by Folin-ciocalteu method,aluminum chloride sodium nitrite and oxygen radical absorption capacity(ORAC) during in vitro simulated digestion process.The results showed that the maximum release of polyphenols for brown rice,rice bran and polished rice were 3.499-,1.753-,6.595-and 4.704-,1.828-,9.113-folder higher than that at the simulated gastric digestive time point 0 h during the simulated gastric digestion process and during simulated gastrointestinal digestion respectivly;the biggest release of flavonoids were 1.522,1.961,1.653 and 3.359,5.958,3.242 times more than that at 0 h as well as the maximum ORAC values raised 3.459,4.849,12.93 and 5.659,5.112,19.65 times respectivly.The results show that the grains bound polyphenols could transfer to free polyphenols during hydrochloric acid and enzymes hydolysis digestion and be available in the upper gastrointestinal tract.