Lipofuscin-Like Substance Involved in Pericarp Browning of Postharvest Litchi Fruit During Storage

Litchi (Litchi chinensis Sonn.) is a subtropical fruit of high commercial value in international trade. However, litchi fruit after harvest can rapidly lose their bright red skin color and turn brown with increasing storage time at ambient temperature. Postharvest browning of litchi fruit is mainly attributed to the degradation of anthocyanins and the oxidation of phenolics. In this study, the contents of lipofuscin-like substance in relation to the levels of anthocyanins and (–)epicatechin, and browning index of litchi fruit during storage were investigated. In a storage period from 72 to 144 h, the relative content of lipofuscin-like substance increased by 51.1% while the contents of (–)-epicatechin and anthocyanins decreased by 41.2 and 98.1%, respectively, and the obvious accumulation of lipofuscin-like substance of pericarp tissue of litchi fruit was related to the reduced contents of anthocyanins and (–)-epicatechin. Furthermore, the increase in the content of lipofuscin-like substance was significantly related to the increased browning index. It is suggested that lipofuscinlike substance could be one of the final products from the browning reaction of litchi fruit during storage.