Evaluation on Effects of Chitosan Derived From Shrimp Shells on Engineering Properties, Antioxidant, Antibacterial, and Microstructural Characteristics of Chitosan–Alginate–Carrageenan‐Based Hydrogels

ABSTRACT This study aimed to evaluate the effects of chitosan, extracted from shrimp shells, on the engineering, antioxidant, antibacterial, and microstructural properties of chitosan–alginate–carrageenan‐based hydrogels. Hydrogels were synthesized with fixed sodium alginate (1.00 g) and carrageenan (0.50 g) while varying chitosan content from 0.50 to 1.50 g (samples of M1, M2, M3, M4, and M5). Among the samples, M3 (1.00 g chitosan) demonstrated optimal performance with a tensile strength of 5.3 MPa, a swelling ratio of 1202% (at pH 7) and 1256% (at pH 11), and the lowest conductivity (306.2 μS/cm). This sample also exhibited the highest scavenging activity (94.95%) after 120 h and maximum antibacterial efficiency (99.2% against E. coli , 99.0% against S. aureus ). Structural characterization revealed that sample M3 had an amorphous structure confirmed by X‐ray diffraction (XRD), with a highly porous microstructure (micron‐sized pores) observed via scanning electron microscopy (SEM), facilitating water absorption and molecular diffusion. Analysis of Fourier transform infrared spectroscopy (FTIR) indicated strong intermolecular interactions through ionic bonds and hydrogen bonding among OH, NH, CO, COO − , OSO 3 − , COC groups. These findings highlight the potential of chitosan‐based natural hydrogels for biomedical, food packaging, and environmental applications.