Abstract: In order to clarify the possibility of edible film as a substitute for traditional preservatives, the fresh-keeping effect of Coptis chinensis Franch (50% ethanol extract from Rhizoma Coptis)-chitosan film on Citrus sinensis (L.) cv. Olinda Valencia orange fruits was investigated. The results showed that the composite coating could significantly decrease disease index and weight loss rate as well as decay fruit rate. Meanwhile, it could also decrease respiration intensity, maintain higher contents of titratable acids and vitamin C and stabilize the content of soluble solids. In addition, the composite coating could enhance the activity of catalase (CAT) in valencia orange fruits. Moreover, compared with the traditional preservation treatment, this coating could maintain higher activities of CAT and SOD in orange fruits during the late stage of storage, consequently inhibiting the accumulation of malondialdehyde (MDA) and maintaining cell membrane integrity. Therefore, this coating not only has similar effect to the traditional preservative in maintaining fruit quality and delaying quality senescence, but also possesses edible safety and environment-friendly characteristics, suggesting its promising application potential as a substitute for traditional preservatives.

Key words: Valencia orange, composite coating, fresh-keeping effect