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This study aims to investigate the preservative effects of chitosan film incorporated with thinned young apple polyphenols (YAP) on grass carp fillets (GCF) quality during cold storage. The results showed that the chitosan-YAP film wrapping effectively retarded the microbial proliferation, lipid and protein oxidation, changes in pH and color values and decrease in water holding capacity of GCF during cold storage. Besides, the wrapping with chitosan-YAP film could significantly delay the decrease in the content and functional properties of soluble myofibrillar protein, the loss of the texture and amino acids, and the adverse changes in the surface morphology and sensory values of GCF. Through correlation analyses, the preservative effects of the film may be attributed to its water retention capacity, antioxidant and antibacterial activities. Therefore, the chitosan-YAP film has a potential as a packaging material to extend shelf life of freshwater fish fillets during cold storage.

The method for separating and purifying chlorogenic acid (CA), epicatechin (EC), hyperoside (HY) and phlorizin (PH) simutaneously from young Qinguan apples by successive use of X-5 and polyamide resins has been developed in this study. The order of adsorption capacities of X-5 for the four phenolics was PH>HY>EC>CA, and the adsorption equilibriums of the four phenolics onto X-5 resin conformed to Langmuir isotherms preferentially. The adsorption kinetics of EC and CA onto X-5 conformed to the pseudo-first-order model, while that of HY and PH accorded with the pseudo-second-order model. Interestingly, the values of equilibrium adsorption capacities (Qe) calculated in the preferential kinetics models were closer to that of theoretical maximum adsorption capacities (Q0) calculated by Langmuir isotherms. Through dynamic adsorption and desorption using X-5 and polyamide resins with ethanol solution as strippant, CA, EC, HY and PH were obtained with purities of 96.21%, 95.34%, 95.36% and 97.36%, respectively.