Comparative analysis of total wax content, chemical composition and crystal morphology of cuticular wax in Korla pear under different relative humidity of storage

Abstract

The cuticular wax of Korla pear stored under different relative humidity (0 ± 1 ℃, 50-55%, 70-75% and 90-95%) was examined in terms of total wax content, chemical composition and crystal morphology. The cuticular wax was composed of alkanes, olefins, fatty acids, alcohols, aldehydes, esters and terpenoids. High humidity maintained the content of total wax, alkanes and aldehydes at sufficient levels, especially C₂₉ alkane and C₁₈ aldehyde, which could positively regulate the quality of the pear fruits. Cuticular wax contributes to the capacity of preserving water, maintaining cell wall and delaying senescence. Scanning electron microscopy showed that wax crystals appeared as numerous platelets with irregular ovate crystals, high humidity delayed the transformation of wax structure. Taken together, high humidity delayed the ripening and aging by effectively maintaining wax, which was essential for postharvest storage and provide a reference for the production of synthetic wax for Korla pear fruits.

Keywords: Chemical composition; Crystal morphology; Cuticular wax; Humidity; Korla pear.