Postharvest Calcium Chloride Treatment Strengthens Cell Wall Structure to Maintain Litchi Fruit Quality

Abstract

Litchi (Litchi chinensis Sonn.) fruit deterioration occurs rapidly after harvest and is characterized by pericarp browning, pulp softening, and decay. In this study, we found that calcium chloride (CaCl2) treatment (5 g L−1 CaCl2 solution vacuum infiltration for 5 min) affected the cell wall component contents and cell wall-degrading enzyme activities of litchi fruit during storage at room temperature. CaCl2 treatment significantly increased the contents of Ca2+ and cellulose, while it decreased the water-soluble pectin content, and the activities of polygalacturonase, β-galactosidase, and cellulase in the litchi pericarp. Meanwhile, the treatment resulted in significantly increased contents of Ca2+, water-soluble pectin, ionic-soluble pectin, covalent-soluble pectin and hemicellulose, and upregulated activities of pectinesterase and β-galactosidase, while significantly decreasing the activities of polygalacturonase and cellulase in litchi pulp. The above results indicate that CaCl2 treatment strengthened the cell wall structure of litchi fruit. More importantly, the enzymatic browning of the pericarp, softening of the pulp, and disease incidence were delayed. The treatment had a more pronounced effect on the pericarp than on the pulp. We consider CaCl2 treatment to be a safe and effective treatment for maintaining the postharvest quality of litchi fruit.

Effect of Pre-Harvest Calcium Treatment on Post-Harvest Fruit Quality of Nanfeng Tangerine

“…However, excessive cytoplasmic Ca 2+ can damage membranes and elevate respiratory rates, leading to increased weight loss, as observed when CaCl 2 concentrations exceeded 1.0%. For example, Guo et al [26] demonstrated that post-harvest treatment of lychee with Ca chloride strengthened the cell wall structure, delaying enzymatic browning of the pericarp, pulp softening, and disease development.…”

Overexpression of the Rubus idaeus Polygalacturonases Gene RiPG2 Accelerates Fruit Softening in Solanum lycopersicum

“…It extracts and clarifies fruit juices, reduces viscosity, and releases nutrients, a property that has led to its use in improving feed absorption and textile degumming [8]. In previous reports, there have also been many studies on the reduction of PG enzyme activity by post-harvest treatment of fruit to improve fruit quality [9,10].…”