Cellulose–pectin composite hydrogels fabricated via LiBr solution: A sustainable approach to freeze–thaw and solvent regenerated networks with enhanced structure–function relationships

Cellulose–pectin composite hydrogels have been synthesized using LiBr solution to investigate the influence of pectin on cellulose network formation and to explore their potential applications in biomaterials. The hydrogels were synthesized via a dissolution-regeneration process, employing various concentrations of cellulose and pectin. FT-IR and XPS confirmed partial demethylation of pectin and reduced hydrogen bonding interactions, while XRD revealed a progressive decrease in crystallinity with increasing pectin content. Mechanical strength tests and WRV measurements demonstrated that excess pectin disrupts cellulose regeneration, resulting in a looser and weaker network. In contrast, freeze–thaw and organic solvent regeneration treatments significantly improved structural stability, restoring hardness and water retention through hydrogen-bond reorganization and network densification. Furthermore, pectinase activity confirmed that the reducing activity of pectin was retained after processing, supporting its role as a functional component of the hydrogel matrix. The antioxidant capacity, measured using the FRAP assay, demonstrated enhanced performance in pectin-containing hydrogels. These findings highlight the potential of LiBr-based cellulose–pectin composite hydrogels, developed through a sustainable approach, in mechanical reinforcement and material applications.