Effect of waxing on postharvest quality and storability of ginger (Zingiber officinal Roscoe)

Desiccation remains a major limiting factor affecting the storage life of many horticultural crop species. The process of waxing, which provides a seal to protect against water loss, is currently the main method for maintaining postharvest quality of many crops. However, the effects of waxing on reducing desiccation, thereby improving postharvest quality of ginger remains unclear. This study investigates the effects of waxing on the common physiological and molecular markers of desiccation, including fresh weight loss, antioxidant system, and endogenous hormones of ginger postharvest. Results showed that both 2% and 4% wax treatments significantly inhibited rhizomes desiccation, marked by the reduced fresh weight loss and maintenance of total protein content in ginger rhizomes. Wax application significantly inhibited the rate of increase in the activities of antioxidant enzymes, including SOD, POD, and CAT, as well as lowered the concentration of MDA-each of which are required for desiccation tolerance. In addition, ABA biosynthesis and signaling were repressed by 2% and 4% wax treatments, indicating that regulation of desiccation by ABA was required. These results demonstrate that waxing of ginger rhizomes adequately reduce the rate at which desiccation may occur in horticultural crops. Therefore, the application of wax is an effective method to reduce postharvest loss of ginger rhizome.