Oliveira Carla M, Ferreira António C S, de Pinho Paula Guedes, Silva Artur M S
Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. Bernardino de Almeida, 4200-072 Porto, Portugal.
J Agric Food Chem. 2008 Nov 12;56(21):10326-31. doi: 10.1021/jf8013662. Epub 2008 Oct 2.
The aim of this study was to obtain new information on antioxidant compounds in white wines. For this purpose, white wine degradation was promoted by a forced aged protocol, and six normally aged white wines from different vintages were analyzed. Both normal and forced aged wines were sequentially extracted using hexane and ethyl acetate. Apolar antioxidants were removed using hexane, and polar antioxidants were extracted with ethyl acetate. This last residue was subject to partial re-extraction with hexane and acetone. The antioxidant capacity of the wines and of each fraction was evaluated by two free radical methods, ABTS and DPPH. Normal aging provides a decrease in the total antioxidant capacity of wines. The antioxidant activity of ethyl acetate/acetone extracts was approximately 95% higher than that found for the hexane extracts. Concerning the forced aged wines, results showed that the wine submitted to a temperature of 60 degrees C for 21 days had higher antioxidant activity than that submitted to a temperature of 20 degrees C. With regard to the ethyl acetate/acetone extracts, oxygen and temperature treatment leads to a decrease in their antioxidant activity. NMR analysis was performed in the highest antioxidant capacity organic fractions (ethyl acetate/acetone extracts) and in the aqueous fraction of the control wine (T = 20 degrees C), in order to attempt the characterization of species involved in oxygen protection. Possible structures of antioxidant compounds in white wines were proposed. Two of these are tyrosol-like structures. This molecule is a well-known phenolic compound in wine, and it is reported to have antioxidative effects.
本研究的目的是获取有关白葡萄酒中抗氧化化合物的新信息。为此，通过强制陈酿方案促进白葡萄酒的降解，并对六种不同年份的正常陈酿白葡萄酒进行分析。正常陈酿和强制陈酿的葡萄酒均依次用己烷和乙酸乙酯萃取。用己烷去除非极性抗氧化剂，用乙酸乙酯萃取极性抗氧化剂。最后这个残余物用己烷和丙酮进行部分再萃取。通过ABTS和DPPH两种自由基方法评估葡萄酒及其各部分的抗氧化能力。正常陈酿会使葡萄酒的总抗氧化能力降低。乙酸乙酯/丙酮提取物的抗氧化活性比己烷提取物的抗氧化活性高约95%。关于强制陈酿的葡萄酒，结果表明，在60摄氏度下放置21天的葡萄酒比在20摄氏度下放置的葡萄酒具有更高的抗氧化活性。对于乙酸乙酯/丙酮提取物，氧气和温度处理会导致其抗氧化活性降低。对抗氧化能力最高的有机部分（乙酸乙酯/丙酮提取物）和对照葡萄酒的水相部分（T = 20摄氏度）进行了核磁共振分析，以尝试表征参与氧气保护的物质。提出了白葡萄酒中抗氧化化合物的可能结构。其中两种是酪醇样结构。这种分子是葡萄酒中一种著名的酚类化合物，据报道具有抗氧化作用。
