Impacts of high pressure assisted freezing on the denaturation of polyphenol oxidase

作者：Cheng, Lina; Zhu, Zhiwei; Sun, Da-Wen^*

来源：Food Chemistry, 2021, 335: 127485.

DOI：10.1016/j.foodchem.2020.127485

• High pressure freezing
• Thermodynamics
• Conformation
• PPO
• Denaturation

The mechanism of enzyme protein denaturation induced by high pressure freezing is complicated and unclear as this process involves Pressure-Factors (pressure and time) and Freezing-Factors (temperature, phase transition, recrystallization, and ice crystal types). In this study, the thermodynamics and conformation changes of mushroom polyphenol oxidase (PPO) under high pressure freezing treatments (HPF, P-100,150,200,300,400,500MPa(20 degrees C/30min)) and high pressure processes (HPP) followed with normal pressure immersion freezing (HPP-IF, P-100500MPa(25 degrees C/30min) - P-0.1MPa(-20 degrees C/30min)) are investigated as compared with that processed under high pressure processes (HPP, P-100-500MPa(25 degrees C/30min)) and normal pressure immersion freezing process (IF, P-0.1MPa(-20 degrees C/30min)). The results suggested that the treated PPO with the same enzyme activity may have various thermodynamic characteristics and conformations; Pressure-Factors play the main roles in the denaturation of the PPO during the HPF treatment, and Freezing-Factors can weak the effect of Pressure-Factors on PPO denaturation; The treated PPO may be transferred into a partially fold intermediate state.

• 单位
  广东省农业科学院