Ti Huihui, Zhang Ruifen, Li Qing, Wei Zhencheng, Zhang Mingwei
Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, PR China.
Sericultural and Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, PR China.
Food Res Int. 2015 Oct;76(Pt 3):813-820. doi: 10.1016/j.foodres.2015.07.032. Epub 2015 Jul 29.
The aim of this study was to analyze the content and distribution of free and bound phenolic components and the oxygen radical absorbance capacity (ORAC) antioxidant activity of brown and polished rice after cooking and in vitro digestion. The results showed that cooking decreased the free and bound phenolic and flavonoid contents and ORAC values. Cooking decreased the total phenolic content of brown and polished rice by 47.9% and 71.0%, total flavonoid content by 72.8% and 82.5%, and total ORAC values by 31.8% and 72.9%, respectively. After in vitro digestion, the total phenolic content, total flavonoid content, and total ORAC values had increased by 195.6%, 34.6% and 185.7%, respectively, in brown rice, and by 403.3%, 13.1% and 293.4% respectively, in polished rice, compared with the cooked samples. Seven individual phenolics (gallic, protocatechuic, chlorogenic, caffeic, syringic, coumaric, and ferulic acids) were detected in both free and bound forms. The results showed that the phytochemical content and its antioxidant activity after cooking will be underestimated if the bound fraction after in vitro digestion is not included in calculations. The results of this study show that cooking affects the phenolic content and antioxidant capacity of rice. However, the in vitro digestion process could actually improve the digestion and absorption of beneficial components of cooked rice at the intestinal level.
本研究旨在分析蒸煮及体外消化后糙米和精米中游离及结合态酚类成分的含量与分布，以及氧自由基吸收能力（ORAC）抗氧化活性。结果表明，蒸煮降低了游离及结合态酚类和黄酮类含量以及ORAC值。蒸煮使糙米和精米的总酚含量分别降低了47.9%和71.0%，总黄酮含量分别降低了72.8%和82.5%，总ORAC值分别降低了31.8%和72.9%。与蒸煮后的样品相比，体外消化后，糙米的总酚含量、总黄酮含量和总ORAC值分别增加了195.6%、34.6%和185.7%，精米分别增加了403.3%、13.1%和293.4%。检测到7种游离和结合态的单一酚类物质（没食子酸、原儿茶酸、绿原酸、咖啡酸、丁香酸、香豆酸和阿魏酸）。结果表明，如果在计算中不包括体外消化后的结合部分，蒸煮后植物化学物质的含量及其抗氧化活性将被低估。本研究结果表明，蒸煮会影响大米的酚类含量和抗氧化能力。然而，体外消化过程实际上可以在肠道水平上改善熟米饭有益成分的消化和吸收。
