Advances in control technologies and mechanisms to treat peel browning in postharvest fruit

This work reviews the main factors contributing to the occurrence of postharvest fruit peel browning, including water loss, chilling injury, disease and mechanical damage. In addition, the present work discusses the potential biochemical mechanisms involved in the occurrence of postharvest peel browning, mainly including insufficient energy supply and reactive oxygen species (ROS) burst. This work updates the progress of methods to control the occurrence of postharvest fruit peel browning, which provides an important reference role to reduce postharvest fruit losses. Notably, although the direct causative factor of peel browning in different fruit is PPO-mediated enzymatic browning of phenolics, the specific substrates of PPO are different in various fruit peels. Some conventional postharvest preservation methods have also shown promising effect in inhibiting postharvest fruit peel browning, while the next batch of candidates for inhibiting peel browning of postharvest fruit are some small molecule substances that have antioxidant activity and improve cell energy supply. However, to better inhibit the occurrence of peel browning, some combinations of conventional postharvest preservation methods should be considered in future studies, which might achieve better and more effective results.