Diano Nadia, Grimaldi Tiziana, Bianco Mariangela, Rossi Sergio, Gabrovska Katya, Yordanova Galya, Godjevargova Tzonka, Grano Valentina, Nicolucci Carla, Mita Luigi, Bencivenga Umberto, Canciglia Paolo, Mita Damiano G
Department of Experimental Medicine, Second University of Naples, Italy.
J Agric Food Chem. 2008 Dec 10;56(23):11471-7. doi: 10.1021/jf8019437.
The catalytic behavior of a mixture of pectic enzymes, covalently immobilized on different supports (glass microspheres, nylon 6/6 pellets, and PAN beads), was analyzed with a pectin aqueous solution that simulates apple juice. The following parameters were investigated: the rate constant at which pectin hydrolysis is conducted, the time (tau(50)) in which the reduction of 50% of the initial viscosity is reached, and the time (tau(comp,dep)) required to obtain complete depectinization. The best catalytic system was proven to be PAN beads, and their pH and temperature behavior were determined. The yields of two bed reactors, packed or fluidized, using the catalytic PAN beads, were compared to the circulation flow rate of real apple juice. The experimental conditions were as follows: pH 4.0, T = 50 degrees C, and beads volume = 20 cm(3). The initial pectin concentration was the one that was present in our apple juice sample. No differences were observed at low circulation rates, while at higher recirculation rates, the time required to obtain complete pectin hydrolysis into the fluidized reactor was found to be 0.25 times smaller than in the packed bed reactor: 131 min for the packed reactors and 41 min for the fluidized reactors.
分析了共价固定在不同载体（玻璃微球、尼龙6/6颗粒和聚丙烯腈珠粒）上的果胶酶混合物，对模拟苹果汁的果胶水溶液的催化行为。研究了以下参数：果胶水解进行的速率常数、达到初始粘度降低50%所需的时间（τ(50)）以及实现完全脱果胶所需的时间（τ(comp,dep)）。已证明最佳催化体系是聚丙烯腈珠粒，并测定了其pH值和温度行为。将使用催化性聚丙烯腈珠粒的两种填充床或流化床反应器的产率与实际苹果汁的循环流速进行了比较。实验条件如下：pH值4.0，温度T = 50℃，珠粒体积 = 20立方厘米。初始果胶浓度为我们苹果汁样品中的浓度。在低循环流速下未观察到差异，而在较高再循环流速下，发现流化床反应器中实现果胶完全水解所需的时间比填充床反应器小0.25倍：填充床反应器为131分钟，流化床反应器为41分钟。
