Technological Institute of Food and Agriculture (CICYTEX-INTAEX). Government of Extremadura. Avda. Adolfo Suárez s/n, 06007 Badajoz, Spain; Agricultural Engineering School, University of Extremadura, Avda. Adolfo Suárez s/n, 06007 Badajoz, Spain.
Agricultural Engineering School, University of Extremadura, Avda. Adolfo Suárez s/n, 06007 Badajoz, Spain; University Research Institute of Agricultural Resource, Avda. de Elvas, s/n, 06071 Badajoz, Spain.
Food Res Int. 2018 Sep;111:299-305. doi: 10.1016/j.foodres.2018.05.057. Epub 2018 May 23.
The aim of this study has been to assess the composition and antioxidant activities of rice bran extracts submitted to a human simulated digestion, which extraction process was previously optimized. In order to adjust the optimum values for the extraction, D-optimal experimental design and response surface methodology have been applied. Phenolic compounds and γ-oryzanol contents have been used as response parameters. In this way, two different extracts have been obtained. The first one, was obtained with 100% water as solvent, and it was mainly composed by phenolic acids. Ferulic acid was the majority compound found with a concentration of 1.00 ± 0.03 mg/g extract, followed by p-coumaric acid (0.19 ± 0.02 mg/g), The second extract, extracted with ethanol as solvent, was a γ-oryzanol enriched fraction with a content of 14.41 ± 0.26 mg/g extract. The optimized rice bran extracts thus obtained were subjected to a process of human in-vitro digestion. In the first extract, with high polyphenol content, the phenolic content was oscillating during the digestion, like antioxidant activity. The oryzanol content found in this fraction (0.079 ± 0.002 mg/g) has not been detected in any phase of digestion. In the second extract, with a high oryzanol content at the beginning, oryzanol content was not detected in any of digestion steps. However, phenolic composition was stable in all phases of simulation (ranging from 0.117 and 0.094 mg/g in the case of ferulic acid). This fact evidence that oryzanol is not a bioavailability fraction, while phenolic compounds support to some extent, the conditions of digestion.
本研究旨在评估经人体模拟消化后的米糠提取物的组成和抗氧化活性，该提取过程之前已进行了优化。为了调整提取的最佳值，应用了 D-最优实验设计和响应面法。酚类化合物和γ-谷维素的含量被用作响应参数。通过这种方式，得到了两种不同的提取物。第一种提取物，用 100%的水作为溶剂，主要由酚酸组成。阿魏酸是含量最高的化合物，浓度为 1.00±0.03mg/g 提取物，其次是对香豆酸（0.19±0.02mg/g）。第二种提取物，用乙醇作为溶剂提取，是一种富含γ-谷维素的馏分，含量为 14.41±0.26mg/g 提取物。因此，优化的米糠提取物经过人体体外消化过程。在含有高多酚含量的第一种提取物中，酚含量在消化过程中波动，如抗氧化活性。在该馏分中发现的谷维素含量（0.079±0.002mg/g）在消化的任何阶段都未检测到。在第二种提取物中，一开始谷维素含量较高，在消化的任何阶段都未检测到谷维素。然而，酚类成分在模拟的所有阶段都保持稳定（阿魏酸的范围为 0.117 和 0.094mg/g）。这一事实表明，谷维素不是生物利用度部分，而酚类化合物在一定程度上支持消化条件。
