高粱糠中不同存在形态酚类物质的组成及抗氧化活性

Composition and Antioxidant Activity of Different Forms of Phenolic Compounds from Sorghum Bran

摘要:

本文提取了高粱糠中的游离酚、可溶性酯型酚、可溶性苷型酚、束缚型酯型酚和束缚型苷型酚，用高效液相色谱法测定其中15种酚类化合物的含量，并对抗氧化能力进行研究，其中包括DPPH自由基、ABTS自由基、O2-自由基清除率的测定，以及Fe3+还原力的测定实验等。实验结果表明：本实验研究的高粱糠的游离酚、可溶性酯型酚、可溶性苷型酚、束缚型酯型酚和束缚型苷型酚的含量分别为645.27、138.57、48.67、118.92、176.06 mg GAE/100 g DW；阿魏酸和水杨酸的含量较高，分别为39.04%和28.04%，3,4-二羟基苯甲酸的含量最低（0.09%）；阿魏酸主要以束缚型的形式存在，可溶性酚中的异绿原酸的含量较高，而游离酚中水杨酸的含量最高；不同存在形态的酚类物质的抗氧化能力在不同的抗氧化体系中略有差异，总的来说，束缚型酯型酚、束缚型苷型酚、可溶性酯型酚的抗氧化能力较强，虽然游离酚含量最高，但其抗氧化能力较弱。

Abstract:

The different forms of phenols, including free, soluble esterified, soluble glycosidic, insoluble-bound esterified, and insoluble-bound glycosidic polyphenols were extracted from sorghum bran. The content of 15 phenolic compounds were determined by high performance liquid chromatography. The antioxidant activities of different forms of phenols were evaluated by measuring the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and superoxide (O2-) radical scavenging activities and Fe3+ reducing ability power. The results showed that the content of free, soluble esterified, soluble glycosidic, insoluble-bound esterified, and insoluble-bound glycosidic phenols in sorghum bran were 645.27, 138.57, 48.67, 118.92, and 176.06 mg GAE/100 g, respectively. The highest phenolic content were found in ferulic acid (39.04%) and salicylic acid (28.04%), while 3,4-dihydroxybenzoic acid showed the lowest phenolic content (0.09%). Ferulic acid was mainly found in insoluble-bound form, and the content of isochlorogenic acid was relatively high in the soluble phenolic compounds, while salicylic acid had the highest content among the free phenolic compounds. In different antioxidant systems, there were slight differences in the antioxidant activities of phenols in different forms. In general, soluble esterified, insoluble-bound esterified, and insoluble-bound glycosidic phenols possesses relatively high antioxidant activities, while free phenols have relatively low antioxidant activity, in spite of having the highest phenol content.