Preparation And Characterization Of Tea Polyphenol/Starch Active Film

Development of biodegradable active films with an incorporation of natural functional additives,has constituted a new strategy to extent shelf-life of food products and to improve the functionality of packaging materials.In this dissertation,starch-based active films were designed and prepared using hydroxypropyl-high amylose?HPS?with an incorparation of tea polyphenol?TP?,which acted as a natural multi-functional active ingredient.According to the optimized conditions of film preparation,HPS-based films with different concentration of TP were produced and the relative physicochemical properties and performance were systematically characterized and compared.Results showed that:The composition of film is vital important for the mechanical and barrier properties,as well as the temperature of preparation.An optimized experimental condition for the films was that,the starch concentration,glycerol content and the preparation temperature were 7%,20%and 70°C,respectively.When the TP content was more than 2.5%,incompletely gelatinized starch granules on the air contact surface of the films reduced obviously.However,an increase in TP content improved the surface hydrophilicity and water solubility.FT-IR spectral analysis indicated that TP inhibited the recrystallization of starch film based on an increased intensity of the absorption peak around 1640 cm^-1.Moreover,the water holding capacity of the films was also improved in the presence of TP.Due to the presence of TP,the mechanical behavior and ultraviolet barrier property of the film were significantly changed,which closely related to the TP content.Comparatively,TP had slight influence on the grease permeability and oxygen barrier property.Moreover,TP addition improved the both antioxidant and antimicrobial effect,and such function was less influenced by normal light and ultraviolet light treatment during the process of storage.The dissolution behavior,antioxidative and antibacterial activity of the active film were also studied during storage.It was showed that in high moisture condition,TP in the film matrix were highly released.Such phenomenon was directly related to the TP content,and a best dissolution was observed as the TP content was about 5%.Meanwhile,it was also confirmed that the antioxidant and antibacterial functions of the film remained relatively stable during the storage of 3⁴ months.Moreover,the study of anti-oxidation of fish oil packaged by the active film showed that such active packaging could keep the quality and safety of food inside it.