Recent Advances in Natural Extract-Based Multifunctional Gels for Food Packaging: A Review

Food packaging plays an essential role in maintaining food quality, safety, and shelf life during storage, transportation, and retail distribution. However, conventional petroleum-derived plastics raise increasing environmental concerns, while many biopolymer-based packaging materials remain limited by insufficient mechanical strength, poor water resistance, limited barrier properties, and unstable active functions. Natural extract-based multifunctional gels provide a promising strategy for sustainable food packaging due to their inherent biocompatibility, structural versatility, and synergistic interplay between active extracts and gel networks, which can immobilize bioactive compounds, regulate mass transfer, and integrate preservation and monitoring functions within one material platform. This review summarizes recent advances in natural extract-based multifunctional gels for food packaging, with emphasis on polysaccharide-based, protein-based, lipid-based, and other naturally derived gel systems. Representative material formats include hydrogels, aerogels, emulsion gels, oleogels, and gel-derived films or coatings, while typical components include chitosan, alginate, pectin, starch, proteins, natural waxes, lignin, anthocyanins, curcumin, polyphenols, and essential oils. Their gelation mechanisms, structural features, preparation strategies, and functional applications are discussed, including antioxidant activity, antimicrobial preservation, barrier enhancement, controlled release, freshness monitoring, and biodegradability. Furthermore, the potential interactions between natural extracts and gel matrices are also discussed, including hydrogen bonding, electrostatic interactions, ionic crosslinking, dynamic covalent bonding, hydrophobic association, and lipid crystallization. The main merits of these systems include renewability, biodegradability, tunable network interactions, active-agent protection, and integration of preservation and monitoring functions, whereas persistent challenges include moisture sensitivity, mechanical instability, variable extract composition, migration safety, and scale-up cost. This review provides guidance for designing natural extract-based gel packaging materials with improved functionality, sustainability, and practical applicability.