热处理对苹果果胶甲酯酶和多酚氧化酶活性影响  

Effect of thermal treatment on the activity of apple pectin methylesterase and polyphenoloxidase

作　　者：廖小军[1] 徐增慧[1] 智先[1] 

机构地区：[1]农业部果蔬加工重点开放实验室/果蔬加工教育部工程研究中心中国农业大学,北京100083

出　　处：《新余高专学报》2009年第3期5-8,共4页Journal of XinYu College

基　　金：国家自然基金(No.30571297);北京自然基金(No.6062015);"十一五"国家科技支撑计划(2006BAD05A02)。

摘　　要：研究了添加抗坏血酸对苹果浊汁中果胶甲酯酶(pectin methylesterase,PME)和多酚氧化酶活性(polyphenoloxi-dase,PPO)热钝化效果影响以及分析了PME热钝化动力学,结果表明,添加0.1%抗坏血酸(ascorbic acid,Vc)显著提高了苹果浊汁中PME和PPO活性以及热稳定性。95℃加热10 min后,PME和PPO活性下降了73.38%和94.10%,PME的热稳定性显著高于PPO。两段式一级反应动力学能较好拟合PME热钝化动力曲线,表明苹果浊汁中PME存在敏感型和稳定型两类同工酶。随着温度升高,敏感型和稳定型同工酶指数递减时间DL和DS值下降,钝化速率常数kL和kS值增大,其活化能EaL和EaS分别为62.57和108.11 KJ/mol。The influence of thermal treatment on the activity of apple PPO and PME were studied. Ascorbic acid as anti - browning agent significantly increased the activity of PME and PPO and their resistance to heat. The maximum reduction in activity of PME and PPO were 73.38% and 94.10% at 95 ℃ for 10 rain, suggesting that PPO was more susceptible to the temperatures than PME. The in- activation kinetics of PME was well fitted to a two - fraction model, indicating that the labile and stable fraction of PME were present. The death reduction time DL and DS for the labile and stable fraction decreased, and the inactivation rate constant kL and kS increased with increasing temperature, their activation energy EaL and EaS was 62.57℃ and 108.11 kJ/mol.

关 键 词：苹果浊汁 果胶甲基酯酶 多酚氧化酶 抗坏血酸 钝化 

分 类 号：S-3[农业科学]