Sericultural & 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 Chem. 2017 Jan 1;214:1-8. doi: 10.1016/j.foodchem.2016.07.038. Epub 2016 Jul 6.
In this study, phenolic profiles and antioxidant activity of rice bran were analyzed following successive treatment by gelatinization, liquefaction and complex enzyme hydrolysis. Compared with gelatinization alone, liquefaction slightly increased the total amount of phenolics and antioxidant activity as measured by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Complex enzyme hydrolysis significantly increased the total phenolics, flavonoids, FRAP and ORAC by 46.24%, 79.13%, 159.14% and 41.98%, respectively, compared to gelatinization alone. Furthermore, ten individual phenolics present in free or soluble conjugate forms were also analyzed following enzymatic processing. Ferulic acid experienced the largest release, followed by protocatechuic acid and then quercetin. Interestingly, a major proportion of phenolics existed as soluble conjugates, rather than free form. Overall, complex enzyme hydrolysis releases phenolics, thus increasing the antioxidant activity of rice bran extract. This study provides useful information for processing rice bran into functional beverage rich in phenolics.
本研究采用糊化、液化和复合酶水解对米糠进行连续处理，分析了米糠的酚类物质组成和抗氧化活性。与单独糊化相比，液化略微增加了总酚类物质的含量和抗氧化活性，如铁还原抗氧化能力（FRAP）和氧自由基吸收能力（ORAC）测定所示。与单独糊化相比，复合酶水解使总酚类物质、类黄酮、FRAP 和 ORAC 分别增加了 46.24%、79.13%、159.14%和 41.98%。此外，还分析了游离或可溶性共轭形式存在的十种酚类物质在酶处理后的情况。阿魏酸的释放量最大，其次是原儿茶酸，然后是槲皮素。有趣的是，很大一部分酚类物质以可溶性共轭物的形式存在，而不是游离形式。总的来说，复合酶水解释放出酚类物质，从而提高了米糠提取物的抗氧化活性。本研究为将米糠加工成富含酚类物质的功能性饮料提供了有用的信息。
