Effect of gallic acid/water-soluble chitosan coating solution on preservation of white shrimp during refrigerated storage

Abstract White shrimp ( Fenneropenaeus chinensis ) is susceptible to melanosis and spoilage during refrigerated storage. The development of natural preservatives to enhance the quality of white shrimp under refrigerated conditions is therefore of significant importance. This study focused on the preservation of the white shrimp using a composite preservative chitosan coating prepared by combining phenolic acids with water-soluble chitosan. The composite preservative formulations were screened through in vitro antioxidant and antibacterial assays, leading to the identification of sample III (water-soluble chitosan + gallic acid) as the optimal formulation. This chitosan coating was subsequently applied to investigate its preservative efficacy on the white shrimp. Results from various analyses of the white shrimp samples stored at 4 °C indicated that treatment with the sample III preservative chitosan coating significantly slowed the increase in pH, reduced the production of total volatile basic nitrogen (TVB-N), and lowered thiobarbituric acid reactive substances (TBARS) values. Additionally, SDS-PAGE analysis revealed that the degree of myofibrillar protein hydrolysis in the white shrimp treated with the sample III coating was significantly lower than that in the control group. These findings confirm that the water-soluble chitosan + gallic acid composite effectively improves the quality of the white shrimp during refrigerated storage.