A Review of Non-Chemical Alternatives to SO2 Fumigation to Prevent Pericarp Browning of Litchi

Abstract

Litchi pericarp browning is a widespread problem caused by a wide range of factors, such as polyphenolsoxidase and peroxidase, disease, desiccation, chilling, senescence, decay, micro-cracks, and heat injury. To overcome these problems, the litchi industry commercially uses SO2, but it leaves undesirable residues. Furthermore, chemical controls of browning have been threatened by consumer preferences and regulatory issues concerning pesticide residues in fruits. Thus, there is a necessity to develop alternatives to maintain the overall quality. Several alternatives to SO2 fumigation, such as hot water brushing, modified/controlled atmosphere storage, bio-control agents, surface coating, cold storage, and irradiation, have been proposed.