Abstract:The effects of various concentrations of tea polyphenols on the grass carp (Ctenopharyngodon idella) preservation capabilities of chitosan cross-linked by Maillard reaction/alginate dialdehyde-cinnamaldehyde/chitosan-tea polyphenol (CMR/ADA-CA/CS-TP) trilayer composite films were investigated. The cross-linked CS layer was first prepared using the Maillard reaction. ADA-CA and CS-TP layers were then formed by layer-by-layer casting, followed by drying. With increasing TP concentration, the film color intensified and its transmittance reduced. The tensile strength of film with a TP mass fraction of 0.04% increased to 31.22 MPa, whereas elongation at film break point was 19.59%~22.44%. In contrast, the barrier performances of the film against water vapor and oxygen declined. As the TP mass fraction reached 0.08%, the DPPH scavenging ability of the film increased to 98.12%. Compared with the control, total viable counts of Staphylococcus aureus and Escherichia coli decreased by 56.44% and 56.29% after 24 h of culture. Furthermore, on day 8 of storage, total volatile basic nitrogen, thiobarbituric acid-reactive substances, and total viable counts in fish wrapped with active film decreased by 45.7%, 50.7%, and 2.33 log•CFU/g, respectively, compared with the control group. In conclusion, a TP mass fraction of 0.06% yielded the best overall performance of the film. This film additive could prolong the shelf life of fish and offers strong potential to be used as active packaging to preserve perishable food.
