Equipe de Chimie Analytique des Molécules BioActives, UMR 7178, France.
J Agric Food Chem. 2011 Feb 23;59(4):1249-55. doi: 10.1021/jf104094c. Epub 2011 Jan 24.
A new analytical method (liquid chromatography-antioxidant, LC-AOx) was used that is intended to separate beer polyphenols and to determine the potential antioxidant activity of these constituents after they were allowed to react online with a buffered solution of the radical cation 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(•+)). Using the LC-AOx method, it was possible to demonstrate that the extent of the antioxidant activity was very much dependent on the phenolic compound considered. The method was also applied to the analysis of beer extracts and allowed the evaluation of their antioxidant activity at different steps of beer processing: brewing, boiling, and fermentation. This study showed that the total antioxidant activity remained unchanged throughout beer processing, as opposed to the polyphenolic content, which showed a 3-fold increase. Hopping and fermentation steps were the main causes of this increase. However, the increase measured after fermentation was attributed to a better extraction of polyphenols due to the presence of ethanol, rather than to a real increase in their content. Moreover, this method allowed the detection of three unknown antioxidant compounds, which accounted for 64 ± 4% of the total antioxidant activity of beer and were individually more efficient than caffeic acid and epicatechin.
一种新的分析方法（液相色谱-抗氧化分析，LC-AOx）被用于分离啤酒多酚，并测定这些成分在与缓冲的自由基阳离子 2,2'-偶氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS(•+)）溶液在线反应后的潜在抗氧化活性。使用 LC-AOx 方法，可以证明抗氧化活性的程度非常取决于所考虑的酚类化合物。该方法还应用于啤酒提取物的分析，并允许在啤酒加工的不同步骤评估其抗氧化活性：酿造、煮沸和发酵。这项研究表明，与多酚含量相比，啤酒加工过程中的总抗氧化活性保持不变，多酚含量增加了 3 倍。啤酒花和发酵步骤是导致这种增加的主要原因。然而，发酵后测量到的增加归因于由于存在乙醇而导致多酚更好地提取，而不是其含量的真正增加。此外，该方法还可以检测到三种未知的抗氧化化合物，它们占啤酒总抗氧化活性的 64±4%，并且比咖啡酸和表儿茶素更有效。
