Superabsorbent and antimicrobial cryogel pads based on gelatin, sodium alginate and zinc oxide nanoparticles: Preparation, characterization and enhanced preservation of aquatic products.

Abstract

In this study, a superabsorbent cryogel pad based on gelatin‑sodium alginate (G/SA) was developed by freeze-drying method and functionalized with nano‑zinc oxide (nZnOs) to enhance the antibacterial preservation of aquatic products. The results showed that the G/SA cryogel exhibited a distinct three-dimensional network structure, along with an ultra-high water absorption rate of 43.26 g/g and an oil absorption rate of 8.78 g/g. The incorporation of nZnOs slightly reduced the water absorption rate (39.75 g/g) and oil absorption rate (8.29 g/g), but significantly improved the mechanical strength, increasing the stress from 950.74 kPa to 1145.42 kPa. Moreover, functionalized with nZnOs effectively reduced the water solubility from 27.07% to 4.41% and imparted pronounced antibacterial properties to the cryogel. The freshness preservation application results demonstrated that, at 4 °C, the cryogel pad inhibited the growth and reproduction of bacteria on the surface of shrimp, effectively maintained the color of shrimp, and extended the shelf life of shrimp from 4 to 6 days. Overall, this functional cryogel pad demonstrated great potential as an eco-friendly and efficient active packaging material for extending the shelf life of aquatic products.