title: Effect of combined high pressure and thermal treatment on kiwifruit peroxidase.
abstract: The effects of high pressure and heat treatments on peroxidase (POD) activity in kiwifruit were investigated. Pressure levels ranging from 200 to 600MPa and temperatures varying from 10 to 50°C were applied for up to 30min. Assays were carried out on crude peroxidase in kiwifruit juice and on partially purified peroxidase in a model system. Pressures higher than 400MPa could be combined with mild heat (⩽50°C) to accelerate enzyme inactivation. Prolongation of the exposure time had no great effect after the first 15min. The slope of POD in kiwifruit juice at 30°C was slightly decreased compared with that in a model system. Furthermore, the optimum pH for POD was 6.0-8.5. The presence of POD isoenzymes and their difference in resistance to pressure were thought to be responsible for the final residual activity observed in this study.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, Jiangsu, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, Jiangsu, People's Republic of China. Electronic address: bjiang@jiangnan.edu.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, Jiangsu, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
keywords: High pressure; Kiwifruit; Peroxidase