Shahidi Fereidoon, Alasalvar Cesarettin, Liyana-Pathirana Chandrika M
Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada.
J Agric Food Chem. 2007 Feb 21;55(4):1212-20. doi: 10.1021/jf062472o. Epub 2007 Jan 24.
Antioxidant efficacies of ethanol extracts of defatted raw hazelnut kernel and hazelnut byproducts (skin, hard shell, green leafy cover, and tree leaf) were evaluated by monitoring total antioxidant activity (TAA) and free-radical scavenging activity tests [hydrogen peroxide, superoxide radical, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical], together with antioxidant activity in a beta-carotene-linoleate model system, inhibition of oxidation of human low-density lipoprotein (LDL) cholesterol, and inhibition of strand breaking of supercoiled deoxyribonucleic acid (DNA). In addition, yield, content of phenolics, and phenolic acid profiles (free and esterified fractions) were also examined. Generally, extracts of hazelnut byproducts (skin, hard shell, green leafy cover, and tree leaf) exhibited stronger activities than hazelnut kernel at all concentrations tested. Hazelnut extracts examined showed different antioxidative efficacies, expected to be related to the presence of phenolic compounds. Among samples, extracts of hazelnut skin, in general, showed superior antioxidative efficacy and higher phenolic content as compared to other extracts. Five phenolic acids (gallic acid, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid) were tentatively identified and quantified (both free and esterified forms). Extracts contained different levels of phenolic acids. These results suggest that hazelnut byproducts could potentially be considered as an excellent and readily available source of natural antioxidants.
通过监测总抗氧化活性（TAA）和自由基清除活性测试[过氧化氢、超氧阴离子自由基和2,2-二苯基-1-苦基肼（DPPH）自由基]，以及在β-胡萝卜素-亚油酸模型系统中的抗氧化活性、对人低密度脂蛋白（LDL）胆固醇氧化的抑制作用和对超螺旋脱氧核糖核酸（DNA）链断裂的抑制作用，评估了脱脂生榛子仁及榛子副产品（果皮、硬壳、绿叶覆盖物和树叶）乙醇提取物的抗氧化功效。此外，还检测了提取物的得率、酚类物质含量以及酚酸谱（游离和酯化部分）。一般来说，在所有测试浓度下，榛子副产品（果皮、硬壳、绿叶覆盖物和树叶）提取物的活性均强于榛子仁提取物。所检测的榛子提取物表现出不同的抗氧化功效，这可能与酚类化合物的存在有关。在所有样品中，榛子皮提取物总体上表现出优于其他提取物的抗氧化功效和更高的酚类物质含量。初步鉴定并定量了五种酚酸（没食子酸、咖啡酸、对香豆酸、阿魏酸和芥子酸）（游离和酯化形式）。提取物中酚酸含量各不相同。这些结果表明，榛子副产品有可能被视为一种优质且易于获取的天然抗氧化剂来源。
