Department of Food Technology, Public University of Navarre, 31006 Pamplona, Spain.
J Agric Food Chem. 2011 Jul 13;59(13):7211-7. doi: 10.1021/jf200833a. Epub 2011 Jun 2.
The thermal modification kinetics of a commercial grape seed extract (GSE) was investigated. A GSE was exposed to 60, 90, and 120 °C for 5, 10, 15, 30, 45, and 60 min. The antioxidant activity (AA) and the absorbance at 420 nm (A(420)) were measured. (+)-Catechin, (-)-epicatechin, procyanidins B1 and B2, and gallic acid were identified and measured. After the thermal treatments, the AA did not show a significant difference (p > 0.05) and both procyanidins and gallic acid increased as well as A(420). (+)-Catechin and (-)-epicatechin decreased. To obtain the activation energy (E(a)) of the changes, a modified Weibull and a combined zero- and first-order model were compared, both followed by the Arrhenius equation. The Weibull model was more accurate. The E(a) values for browning and (+)-catechin, (-)-epicatechin, gallic acid, and procyanidins B1 and B2 were 170, 286, 42, 102, 249, and 95 kJ/mol, respectively. The results were valid at a confident level of 95%.
研究了商业葡萄籽提取物（GSE）的热改性动力学。将 GSE 暴露于 60、90 和 120°C 下 5、10、15、30、45 和 60 min。测量抗氧化活性（AA）和 420nm 处的吸光度（A(420)）。鉴定并测量了（+）-儿茶素、（-）-表儿茶素、原花青素 B1 和 B2 以及没食子酸。经过热处理后，AA 没有显著差异（p > 0.05），原花青素和没食子酸增加，A(420)也增加。（+）-儿茶素和（-）-表儿茶素减少。为了获得变化的活化能（E(a)），比较了改进的 Weibull 模型和零级和一级联合模型，均遵循 Arrhenius 方程。Weibull 模型更准确。褐变和（+）-儿茶素、（-）-表儿茶素、没食子酸以及原花青素 B1 和 B2 的 E(a)值分别为 170、286、42、102、249 和 95 kJ/mol。结果在置信水平为 95%时有效。
