茶多酚对普鲁兰-明胶膜理化及抗氧化、抗菌性能的影响

Effects of Tea Polyphenols on Physicochemical,Antioxidant and Antibacterial Properties of Pullulan-Gelatin Films

茶多酚因其优异的抗氧化和抗菌性能,在食品领域被广泛应用。通过制备茶多酚-普鲁兰-明胶复合生物活性膜,研究茶多酚的质量分数(0%、2%、4%、6%、8%、10%,基于明胶和普鲁兰的总干质量)对膜理化性质及抗氧化、抗菌性能的影响。傅里叶红外光谱和扫描电子显微镜结果表明:茶多酚与普鲁兰多糖和明胶之间存在分子间相互作用,尤其当茶多酚质量分数为6%时,膜结构更加致密。理化实验结果表明:随着茶多酚质量分数的增加,复合膜的抗拉强度和断裂伸长率均先增大后减小,水蒸气透过性先减小后增大,紫外线阻隔性能增强,膜变得更暗黄;而茶多酚的添加没有显著提高复合膜的热性能。此外,复合膜对DPPH自由基的清除率最高达87.44%,对大肠杆菌和金黄色葡萄球菌的最大抑制率分别为95.73%和85.22%。同时,复合膜能实现茶多酚的缓慢释放。茶多酚-普鲁兰-明胶复合膜的制备旨在为良好生物活性包装膜的开发提供有益参考。

Tea polyphenols have been widely used in the food field due to their excellent antioxidant and antibacterial properties.By preparing tea polyphenols-pullulan-gelatin composite bioactive films,the effects of the mass fraction of tea polyphenols(0%,2%,4%,6%,8%,and 10%,based on the total dry weight of gelatin and pullulan)on the physicochemical properties,antioxidant and antibacterial properties of the films were studied.FTIR and SEM results showed that intermolecular interactions between tea polyphenols and pullulan and gelatin were appeared,especially when the mass fraction of tea polyphenols was 6%,the film structure became denser.Physical and chemical experiment results showed that,with the increase of the mass fraction of tea polyphenols,the tensile strength and elongation at break of the composite films first increased and then decreased,while the water vapor permeability first decreased and then increased.Meanwhile,the UV resistance increased and the films became darker and yellower.However,the addition of tea polyphenols did not significantly improve the thermal performance of the composite films.In addition,for the composite films,their maximum scavenging rate of DPPH radical was 87.44%and the maximum inhibition rate of Escherichia coli and Staphyloccus aureus were 95.73%and 85.22%,respectively.At the same time,the composite films could realize slow-release of tea polyphenols.The preparation of tea polyphenols-pullulan-gelatin composite films was aimed to provide a useful reference for the development of good bioactive packaging films.