Graduate Institute of Food Science and Technology, National Taiwan University, Taipei 10672, Taiwan.
J Agric Food Chem. 2011 Jul 27;59(14):7818-24. doi: 10.1021/jf200817e. Epub 2011 Jun 21.
Nonenzymatic browning occurs readily in alcoholic beverages and degrades their color quality. Ascorbic acid degradation in the presence of phenolic compounds is a major browning pathway in alcoholic beverages with fruit or fruit juice as the raw material or an ingredient. In the present study ethanolic solutions of ascorbic acid and catechin were prepared to simulate the alcoholic beverages. Ascorbic acid degradation and browning in these model solutions were investigated. Glycerol solutions with the same water activity (A(w)) values as those of the ethanolic model solutions were used as controls in the evaluation of browning rate. Results showed that the aerobic degradation of ascorbic acid dominates over the anaerobic one in ethanolic solutions, that the browning rate decreases as the ethanol concentration increases, that the compound 3-hydroxy-2-pyrone may not be a good indicator of browning in ethanolic ascorbic acid-catechin solutions, and that A(w) is a major factor responsible for the difference in the browning rate among ascorbic acid-catechin solutions with different ethanol concentrations.
非酶褐变在酒精饮料中很容易发生，并降低其颜色质量。在含有酚类化合物的情况下，抗坏血酸的降解是水果或果汁作为原料或成分的酒精饮料的主要褐变途径。在本研究中，制备了抗坏血酸和儿茶素的乙醇溶液来模拟酒精饮料。研究了这些模型溶液中抗坏血酸的降解和褐变。具有与乙醇模型溶液相同水活度 (A(w)) 值的甘油溶液用作褐变速率评估的对照。结果表明，在乙醇溶液中，抗坏血酸的需氧降解占主导地位，随着乙醇浓度的增加，褐变速率降低，3-羟基-2-吡喃酮化合物可能不是乙醇抗坏血酸-儿茶素溶液褐变的良好指标，并且 A(w)是导致不同乙醇浓度下抗坏血酸-儿茶素溶液褐变速率差异的主要因素。
