为开发性能更优、可生物降解的食品保鲜材料，以壳聚糖和结冷胶为原料制备可食用性复合膜。该研究通过羧甲基化和胆酸化改性壳聚糖，使其具有两亲性，并使改性后壳聚糖易溶于水；再进行羧甲基化改性结冷胶，使其在常温下为均一水溶性材料，不再形成凝胶状，利用傅里叶红外光谱，核磁氢谱等对其结构进行表征；该研究以改性壳聚糖为主要成膜材料，结冷胶为增强相、丙三醇为增塑剂，制备了两亲性壳聚糖/改性结冷胶复合膜，并对复合膜进行力学、热学、光学性能进行探究。结果表明，在55 ℃干燥24 h条件下，当两亲性壳聚糖与改性结冷胶质量比为5:2，丙三醇添加量为2%，此时复合膜最大热降解速率推迟到260 ℃左右，透明度达到84%，同时机械性能的拉伸强度值达到最大3.35 MPa，断裂伸长率达到111.00%。此条件下的复合膜热稳定性和机械性能最优，透明度保持较高，感观评定较好，结冷胶的加入改善了壳聚糖的热稳定性与机械性能。

To develop food preservation materials with better performance and biodegradability, edible composite membranes were prepared using chitosan and gellan gum as raw materials. In the present work, chitosan was modified via carboxymethylation and cholic acid, which conferred amphiphilic properties and allowed ready dissolution of the modified chitosan in water. Gellan gum was modified via carboxymethylation to prevent gel formation and make it uniformly water-soluble at room temperature. The structures of the modified materials were characterized using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The modified chitosan was used as the main film-forming material, gellan gum as the reinforcing phase, and glycerol as the plasticizer in the preparation of amphiphilic chitosan/modified gellan gum composite membranes. Subsequently, the mechanical, thermal, and optical properties of the composite membranes were investigated. Results indicated that, under conditions of drying at 55 ℃ for 24 h wherein the mass ratio of amphiphilic chitosan to modified gellan gum was 5:2 and the content of added glycerol was 2%, the temperature at which the thermal degradation rate of the composite membrane reached a maximum was increased to approximately 260 ℃. Moreover, a membrane transparency of 84% was achieved. Tensile strength reached a maximum of 3.35 MPa, and the elongation at break was increased to 111.00%. Under these conditions, the composite membrane achieved optimum thermal stability and mechanical properties, high transparency, and good sensory evaluation results. Therefore, the addition of gellan gum improved the thermal stability and mechanical properties of chitosan.

海南省科技厅科技项目（ZDYF2021XDNY145）；云南省李普旺专家工作站（202005AF150007）；广东省基础与应用基础研究基金资助（2019A1515010714）；广东省现代农业产业技术体系创新团队建设专项（2019KJ140）