流延法制备壳聚糖单层膜及羧甲基纤维素钠/壳聚糖复合膜，并测定膜机械性能、微观结构和水蒸气透过性等对其进行表征；以春香和柠檬两个柑橘品种为试材，研究壳聚糖单层涂膜及羧甲基纤维素钠/壳聚糖自组装复合涂膜对两种柑橘果实（春香，柠檬）采后货架期品质的影响。结果发现：复合膜的水蒸气透过性显著（p<0.05）高于单层膜，为壳聚糖单层膜的1.74倍；且维持良好的力学性能及微观结构。应用于柑橘采后保鲜，发现涂膜可提高柑橘果亮度，抑制抗坏血酸氧化，减少硬度降低。涂膜处理可减少柑橘果实表面气孔数量，降低贮藏期间柑橘果实失重率，贮藏20 d处理组失重率均在7.5%以下；且涂膜延缓了柑橘可滴定酸含量的下降。与单层涂膜相比，羧甲基纤维素钠/壳聚糖自组装复合涂膜可显著（p<0.05）提高春香、柠檬硬度及抗坏血酸含量。经20 d贮藏，复合涂膜组的春香及柠檬硬度分别是对照组的1.15倍、1.23倍。复合膜证实了静电吸附自组装形成的多糖基膜具有维持柑橘采后品质的潜力，为开展不同柑橘品种生物涂膜保鲜研究提供参考。

The single-layer chitosan film and the Na-carboxymethyl cellulose/chitosan double-layer film were prepared by casting method, and the mechanical properties, microstructure and water vapor transmission rate were investigated. Two Citrus varieties of Chunxiang and lemon were used as test materials. The effects on the postharvest quality of two Citrus fruits (Chunxiang, lemon) during shelf life by chitosan monolayer coating and Na-carboxymethyl cellulose/chitosan self-assembled coating were studied. Results showed that the water vapor permeability of the composite film significant (p<0.05）higher than single-layer film and it was 1.74 times that of the chitosan film. What’s more, it could maintain good mechanical properties and microstructure. Applied to the Citrus preservation, the film could improve the lightness of Citrus, inhibit the oxidation of ascorbic acid (Vc) and reduce the decline of firmness. By reducing the number of stomata on the surface of Citrus fruit, coating can effectively reduce weightlessness rate which controlled in 7.5% during storage and delay the decline on titratable acid content of Citrus fruit. Compared with single-layer coating, Na-carboxymethyl cellulose/chitosan self-assembled coating can significantly (p<0.05) improve the postharvest quality of Chunxiang and lemon, maintain high firmness and Vc content, and prolong the storage period. After 20 d of storage, the firmness of Chunxiang and lemon were 1.15 and 1.23 times that of the control group, respectively. This work confirmed that the polysaccharide film formed by electrostatic adsorption and self-assembly had the potential to maintain postharvest quality of Citrus fruits and provided reference for the study on the preservation of biological coating film on different Citrus varieties.

浙江省自然科学基金一般项目（LY17C200008）；浙江省公益技术研究项目（LGN18C200022）；国家重点研发计划项目（2017YFD0401305）；天津市林果产业技术体系（ITTFPRS2018009）；农业农村部重点实验室开放课题（KLAPPH2-2017-07）；浙江科技学院青年科学基金（2019QN21）；中国博士后科学基金面上资助（2018M641659）