番茄汁和纯化形式中果胶甲酯酶失活动力学的比较研究

Comparative study of the inactivation kinetics of pectinmethylesterase in tomato juice and purified form.

作者信息

Fachin Diana, Van Loey Ann M, Ly Nguyen Binh, Verlent Isabel, Indrawati Indrawati, Hendrickx Marc E

机构信息

Pontificia Universidade Católica do Paraná, Brazil, and Laboratory of Food Technology, Department of Food and Microbial Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, B-3001 Leuven, Belgium.

出版信息

Biotechnol Prog. 2002 Jul-Aug;18(4):739-44. doi: 10.1021/bp0155080.

DOI:10.1021/bp0155080

PMID:12153307

Abstract

Pectinmethylesterase (PME) extracted from tomato fruit was purified by affinity chromatography. A single peak of PME activity was observed, presenting a molar mass of 33.6 kDa, an isoelectric point higher than 9.3, and an optimal temperature and pH for activity of 55 degrees C and 8.0, respectively. The processing stability of purified tomato PME in buffer solution was compared to PME stability in tomato juice. In both media, thermal inactivation of PME presented first-order inactivation kinetics, PME in tomato juice being more heat-labile than purified PME. Regarding high-pressure treatment, tomato PME showed to be very pressure-resistant, revealing an outspoken antagonistic effect of temperature and pressure. To avoid cloud loss in tomato juice, a time-temperature treatment of 1 min at 76.5 degrees C was calculated in order to have a residual PME activity of 1 x 10(-)(4) U/mL.

摘要

从番茄果实中提取的果胶甲酯酶（PME）通过亲和色谱法进行纯化。观察到PME活性的单一峰，其摩尔质量为33.6 kDa，等电点高于9.3，活性的最佳温度和pH分别为55℃和8.0。将纯化的番茄PME在缓冲溶液中的加工稳定性与PME在番茄汁中的稳定性进行了比较。在两种介质中，PME的热失活均呈现一级失活动力学，番茄汁中的PME比纯化的PME对热更不稳定。关于高压处理，番茄PME显示出非常耐压，揭示了温度和压力之间明显的拮抗作用。为避免番茄汁出现浑浊损失，计算出在76.5℃下进行1分钟的时间-温度处理，以使PME残留活性为1×10⁻⁴ U/mL。