Multifunctional Hydrogel based on Chlorella Protein: Structure, Performance and Application in Cherry Preservation

This study presents a novel multifunctional hydrogel synthesized by crosslinking Chlorella protein using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/n-hydroxysuccinimide, aimed at extending the shelf life of perishable fruits like cherries. Structural, rheological, and scanning electron microscopy analyses revealed that Chlorella protein hydrogels (CPH) possess excellent solid-like properties and a stable porous structure. The water-holding capacity improved significantly from 67.11 ± 0.72% to 96.53 ± 0.61% with increasing CP concentration (10–22.5%, w/v). Additionally, CPH decomposition temperatures were ~ 150 °C (5% weight loss), demonstrating good thermal stability. Due to the ionization of -COOH and -NH₂ groups, the CPH showed excellent pH sensitivity, with low dissolution rates in acidic environments (64.97%) and significantly higher rates in alkaline environments (448.50%). Furthermore, the CPH inhibited the penetration of Staphylococcus aureus and Escherichia coli, and exhibited good free radical scavenging abilities against DPPH (74.50%) and ABTS^•+ (97.92%). In cherries preservation tests, CPH extended preservation time to 15 days compared to 5 days in the control group, effectively inhibiting decay, suggesting CPH is a promising choice for multifunctional fruit preservation.