Food Chemistry, Department of Food Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg C, Denmark.
Food Chem. 2012 Dec 15;135(4):2195-202. doi: 10.1016/j.foodchem.2012.07.025. Epub 2012 Jul 16.
The antioxidant effects of α-tocopherol (TOH) in combination with green tea extract (GTE), the green tea polyphenol (-)-epicatechin (EC) or the isomeric (+)-catechin (C), were investigated using different lipid systems based on high linoleic sunflower oil: bulk oil, o/w-emulsion and a phosphatidylcholine-based liposome system. Both polyphenols as well as TOH were efficient antioxidants in all systems when used alone, as detected by the formation of free radicals and conjugated dienes and by oxygen consumption. Strong synergistic effect was found for the combination of TOH and GTE in a methyl linoleate o/w-emulsion and in the pure bulk oil, while only an additive effect was observed in a liposome system. The synergism was already evident for the tendency for radical formation in the bulk oil as detected by electron spin resonance (ESR) spectroscopy. On the contrary, combinations of TOH with either EC or C showed clear synergistic effects in both heterogeneous systems, but antagonistic or additive effects in bulk oil. GTE may accordingly be used to protect both vegetable oils and their emulsions against oxidation through enhancement of the activity of their endogenous antioxidants, while GTE is less efficient in the protection of phospholipids as in liposomes.
研究了α-生育酚（TOH）与绿茶提取物（GTE）、绿茶多酚（-）-表儿茶素（EC）或异构体（+）-儿茶素（C）联合使用时对基于高亚油酸葵花籽油的不同脂质系统的抗氧化作用：体相油、O/W 乳液和基于磷脂酰胆碱的脂质体系统。单独使用时，两种多酚和 TOH 都是有效的抗氧化剂，可通过自由基和共轭二烯的形成以及耗氧量来检测。在甲基亚油酸 O/W 乳液和纯体相油中，发现 TOH 和 GTE 的组合具有很强的协同作用，而在脂质体系统中仅观察到相加作用。在通过电子自旋共振（ESR）光谱检测的体相油中自由基形成的趋势已经显示出协同作用。相反，TOH 与 EC 或 C 的组合在两种非均相系统中均显示出明显的协同作用，但在体相油中则表现出拮抗或相加作用。因此，GTE 可通过增强其内源性抗氧化剂的活性来保护植物油及其乳液免受氧化，而 GTE 对脂质体中的磷脂的保护作用则较低。
