葡萄籽和皮中黄酮成分和抗氧化能力研究

通过高效液相色谱(HPLC)分析了酿酒葡萄中的梅鹿辄和霞多丽品种的籽和皮及圆叶葡萄品种麝香葡萄籽中主要单体黄酮醇和酚酸种类，并测定了葡萄籽和皮中的单体黄酮醇和酚酸对总抗氧化能力的贡献。结果表明：麝香葡萄籽中没食子酸、儿茶素、表儿茶酸的含量为68，7和69mg／100g干重，而在霞多丽葡萄籽相应为10，211和303mg／100g干重，梅鹿辄葡萄籽中为7，74和83mg/100g干重。这3种成分在葡萄酒副产物的皮中的含量低于籽中，采用抗氧化能量指数法(ORAC)测定其抗氧化能力贡献占总抗氧化能力的17％。在葡萄籽或皮中的酚类对过氧化游离基清除能力从大到小依次为：白藜芦醇、儿茶素、表儿茶酸=没食子儿茶精、没食子酸=鞣花酸。葡萄籽中抗氧化能力的最主要物质是二聚、三聚、寡聚或多聚原花青素。

MAJOR FLAVONOIDS AND THEIR ANTIOXIDANT CAPACITY IN GRAPE SEEDS AND SKINS

Seeds and skins from grapes of Vitis vinifera varieties Merlot and Chardonnay and in seeds from grapes of Vitis rotundifolia variety Muscadine were analyzed with HPLC for the major monomeric flavanols and phenolic acids. The contribution of the major monomeric flavanols and phenolic acid to the total antioxidant capacity of grape seeds and skins was also determined. Gallic acid, catechin and epicatechin concentrations were 68, 7, and 69 mg/100 g d. m. in Muscadine seeds, 10, 211, and 303 mg/100 g d. m. in Chardonnay seeds, and 7, 74, and 83 mg/100 g d. m. in Merlot seeds, respectively. Concentrations of these three compounds were lower in winery byproduct grape skins than seeds. These three major phenolic constituents of grape seeds contributed less than 17% to the antioxidant capacity measured as ORAC. Peroxyl radical scavenging activities of phenolics present in grape seeds or skins in decreasing order were resveratrol > catechin > epicatechin = gallocatechin > gallic acid = ellagic acid. The results indicated that dimeric, trimeric, oligomeric or polymeric procyanidins account for most of the superior antioxidant capacity of grape seeds.