Degradation mechanism of cuticular wax composition and surface properties of bamboo culm during storage

Abstract

Cuticular wax on bamboo culm forms a kind of protective biointerface during growing and degrades after harvesting leading to the deterioration of surface quality and protection function during storage. The degradation mechanism of the cuticular wax and surface property of harvested bamboo culm during storage is still unclear. To understand it, the microstructure of cuticular wax on the harvested bamboo culm was characterized and composition content was analyzed by GC-MS as well as the contact angle and color of bamboo culm surface were tested after the bamboo culm was stored in four simulated seasons: spring, summer, autumn and winter. The results showed that the more wax deposited on bamboo culm surface during storage, and the thickness of cuticular wax increased. During storage, the content of alkanes, alcohols and total ketone in bamboo culm cuticular wax decreased as well as the contents of terpenoids and esters increased. This suggested that the degradation of cuticular wax on bamboo culm should be due to the hydrolysis of alkane into fatty acids and terpenoids.The surface contact angle of stored bamboo culm decreased and the color of bamboo culm changed. The contact angle of the stored bamboo culm surface reduced 12.24%, 25.53%, 9.76%, 1.85% compared with the fresh bamboo culm. The surface color of bamboo culm was related to the content of cuticular wax and weight loss of bamboo culm and was the joint function of weight loss and wax content change.