Ravber Matej, Pečar Darja, Goršek Andreja, Iskra Jernej, Knez Željko, Škerget Mojca
Faculty of Chemistry and Chemical Engineering, University of Maribor , Smetanova 17, SI-2000 Maribor, Slovenia.
Jožef Štefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia.
J Agric Food Chem. 2016 Dec 7;64(48):9196-9202. doi: 10.1021/acs.jafc.6b03191. Epub 2016 Nov 28.
The model glycoside compound quercetin-3-O-rutinoside (rutin) was subjected to subcritical water within the temperature range of 120-220 °C, and the hydrothermal degradation products were analyzed. Two kinetic models describing the degradation of this compound in two different atmospheres (N and CO), used for pressure establishment in the reactor, have been developed and compared. Reaction was considered a successive one with three irreversible steps. We confirmed that rutin degradation to quercetin follows first-order kinetics. At higher temperatures quercetin is further degraded in two degradation steps. Formations of 3,4-dihydroxybenzoic acid and catechol were described with the zero-order kinetic models. Reaction rate constants for hydrolysis of glycoside to aglycone in a CO atmosphere are higher compared to those in a N atmosphere, whereas at higher temperatures reaction rate constants for further two successive reactions of aglycone degradation are slightly lower in the presence of CO. The difference in reaction activation energies is practically negligible for both gases. Furthermore, degradation products of sugar moieties, that is, 5-hydroxymethylfurfural and 5-methylfurfural, were also detected and analyzed.
将模型糖苷化合物槲皮素 - 3 - O - 芦丁糖苷（芦丁）置于120 - 220°C温度范围内的亚临界水中，并对水热降解产物进行分析。已开发并比较了两种动力学模型，用于描述该化合物在两种不同气氛（N和CO）下在反应器中建立压力时的降解情况。反应被认为是具有三个不可逆步骤的连续反应。我们证实芦丁降解为槲皮素遵循一级动力学。在较高温度下，槲皮素会在两个降解步骤中进一步降解。3,4 - 二羟基苯甲酸和儿茶酚的形成用零级动力学模型描述。与在N气氛中相比，在CO气氛中糖苷水解为苷元的反应速率常数更高，而在较高温度下，在CO存在下苷元进一步连续两个反应的反应速率常数略低。两种气体的反应活化能差异实际上可以忽略不计。此外，还检测并分析了糖部分的降解产物，即5 - 羟甲基糠醛和5 - 甲基糠醛。
