壳聚糖/微晶甾醇可食性复合膜的制备、性能及结构表征

以壳聚糖为成膜基质,添加具有抗氧化和抑菌作用的植物甾醇,采用流延法制备壳聚糖/微晶甾醇可食性复合膜,旨在赋予壳聚糖膜抗氧化活性及提高其抑菌性。当甾醇添加量分别为壳聚糖质量的0%~12%时,随着添加比例的增加,复合膜的拉伸强度和断裂伸长率逐渐下降,溶解度和溶胀度逐渐增加,水蒸气透过系数显著降低,对超氧阴离子自由基(O_2~-·)及羟自由基(·OH)的清除率显著提高,对金黄色葡萄球菌和大肠杆菌的抑菌性能明显增强;采用红外光谱、扫描电子显微镜、X射线衍射和热重分析表征了复合膜的相容性。结果表明:甾醇添加量为9%的壳聚糖/微晶甾醇可食性复合膜各项性能指标良好,且壳聚糖与甾醇分子之间形成了分子间氢键,有较强的相互作用,整个共混体系的相容性良好。

Preparation,Properties and Structural Characterization of Chitosan/Microcrystalline Sterol Composite Edible Films

Chitosan/microcrystalline sterol composite edible films were prepared by flow casting method using chitosan as a film-forming material, where phytosterols were added for their antioxidant and antimicrobial properties. With increasing addition of phytosterols up to 12% (relative to the mass of chitosan), the tensile strength and elongation at break of composite films declined gradually, the solubility and swelling degree gradually increased, and the water vapour permeability coefficient remarkably reduced, indicating an improved moisture barrier property after the addition of sterol. In addition, the superoxide anion and hydroxyl radical scavenging capacities of films were improved remarkably, and the antimicrobial activity against Staphylococcus aureus and Escherichia coli were significantly enhanced. The compatibility of composite films was analyzed by infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetry (TG). The films with 9% sterol added showed good performance. Moreover, chitosan-sterol complexes were formed by strong intermolecular hydrogen bonding interactions, and the blend system had good compatibility.