壳聚糖/明胶/纳米氧化锌复合膜的制备及其性能研究

Preparation of chitosan/gelatin/zinc oxide nanocomposite films and their properties

壳聚糖和明胶来源于天然且具有良好的成膜性,但是两者的抑菌性能较差,因而限制了它们在食品包装中的应用.为提高壳聚糖/明胶复合膜的抑菌性,本研究以壳聚糖和明胶为成膜材料并添加纳米氧化锌为抗菌材料,以共混法制备了壳聚糖/明胶/纳米氧化锌复合膜,探讨了纳米氧化锌含量对壳聚糖/明胶/纳米氧化锌复合膜结构、力学性能以及抑菌性能的影响.研究结果表明,当复合膜中纳米氧化锌含量为0.5%时复合膜抑菌性能最佳,此时其水溶性为17.3%、吸水率为100.0%、拉伸强度为5.5 MPa、断裂伸长率为8.0%、水蒸气透过率为94.72 g·m^(-2)·h^(-1)、透湿系数为2.44×10^(-12)g·cm^(-1)·s^(-1)·Pa^(-1)、金黄色葡萄球菌(Staphylococcus aureus)和大肠杆菌(Escherichia coli)的抑菌圈直径分别为(37.8±0.1) mm和(25.7±0.1) mm,具有良好的力学性能和抗菌性能,在食品保鲜膜,特别是水果保鲜液膜方面有广阔的应用前景.

Chitosan and gelatin come from natural sources and have good film-forming properties,but both have poor bacteriostatic performance,which limits their application in food packaging.In order to enhance antimicrobial activity of the film,nano-zinc oxide was incorporated in gelatin/chitosan composite film.In this study,chitosan and gelatin were used as film-forming materials and nano-zinc oxide was added as antibacterial material,and the composite film was prepared by blending method.The effects of nano-zinc oxide content on the structure,mechanical properties and antibacterial properties of chitosan/gelatin/nano-zinc oxide composite films were investigated.The results showed that the introduction of nano-zinc oxide effectively improved the mechanical properties,water vapor permeability,thermal stability and antibacterial properties of the composite film.When the content of nano-zinc oxide in the composite film is 0.5%,the antibacterial performance of the composite film was the best,with the water solubility of 17.3%,the water absorption rate of 100.0%,the tensile strength of 5.5 MPa,the elongation at break of 8.0%,the water vapor transmittance of 94.72 g·m^(-2)·h^(-1),the water vapor permeability of 2.44×10^(-12) g·cm^(-1)·s^(-1)·Pa^(-1),and the diameter of the zone of inhibition of Staphylococcus aureus of(37.8±0.1)mm and Escherichia coli of(25.7±0.1)mm.These findings indicate that chitosan/gelatin/nano-zinc oxide composite films have great potential to be developed as biodegradable alternative for postharvest packaging of fresh fruits and vegetables.