Chitosan-graft-Pomegranate Extract Hydrogel: A Dual-Functional Pad for Antibacterial and Antioxidant Enhancement for Shelf Life Extension in Food Packaging

Abstract

In the preservation of water-rich foods, especially meat, spoilage can occur due to bacterial contamination and oxidative degradation. This study aimed to determine the structural characteristics and synthesis of the chitosan-graft-pomegranate extract (CS-g-POM) hydrogel using a cost-effective and biobased method to develop antibacterial and antioxidant pads. Pomegranate extract is used to fabricate covalently and noncovalently interconnected chitosan hydrogel networks. Several characterization methods, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, atomic force microscopy, and rheological analysis, confirmed the successful design of the produced hydrogel. The freeze-dried CS-g-POM hydrogel had a swelling ratio of 373%, 614%, and 508.5% at pH 5, 7.4, and 10, respectively. FE-SEM images showed the porous hydrogel, which confirmed the cross-linking process. The addition of pomegranate extract increased the phenolic content, resulting in a DPPH radical scavenging activity of 50.20%. The hydrogel also had good antibacterial properties, with the inhibition zones against Escherichia coli and Staphylococcus aureus measuring 18 ± 1 mm and 12 ± 1 mm. The CS-g-POM hydrogel plays a crucial role in moisture absorption in water-rich foods such as meat due to its high degree of swelling and could be used as an antibacterial absorption pad.