Characterization and Inhibition of Plant Polyphenol Oxidase for Quality Preservation in Post-Harvest Processing

Polyphenol oxidase (PPO), an important copper-containing redox enzyme, is widely distributed among plants, animals, and microorganisms. PPO plays a crucial role in various physiological processes in plants, including stress resistance, photosynthesis, fruit ripening, and tea processing. However, the enzymatic browning reaction mediated by PPO often leads to the deterioration of fruit and vegetable quality during post-harvest processing and storage, posing a significant challenge for the food industry. This article systematically reviews the enzymatic characteristics of plant PPO, including optimal reaction temperature, pH value, substrate specificity, and catalytic mechanisms. Additionally, it summarizes the fundamental mechanisms of enzymatic browning and its inhibition strategies while reviewing systematic techniques for the extraction and purification of PPO, highlighting both the advantages and disadvantages as well as the application scope of simple preparation and fine purification. In conclusion, by synthesizing the current research landscape, this review provides a forward-looking perspective on the potential applications of PPO in elucidating molecular mechanisms, functional regulation, and its utilization in the agricultural and food industries. The review aims to offer theoretical references for research areas such as enzymatic browning control and biotechnological fermentation applications.