Plant-based functional and active agents in sustainable food packaging: a comprehensive review.

The shift to the circular economy has led to the use of plant-based functional ingredients in sustainable food packaging. Renewable, biodegradable, and non-toxic polysaccharides, proteins, lipids, and biopolymers include alginate, chitosan, starch, cellulose, pectin, soy protein, and polylactic acid (PLA). Hydrophobization gives antibacterial, antioxidant, UV-protective, and pH-responsive properties. Lignin is an antioxidant, antibacterial, and UV-blocking filler. A blend of carboxymethyl chitosan and soy protein isolate has almost 100% antimicrobial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), 98.5% UV protection, and prolongs the shelf life of grapes to over 15 days. Microcapsules made of plant proteins (98% biodegradable) release the hydrophilic and hydrophobic compounds, which promote the functional design of packaging. Nevertheless, quantitative benchmarking shows that essential oils cut tensile strength by 20-40%, and unmodified polysaccharide films have 5-15 times higher water vapor transmission rates than polyethylene (50-150 vs. less than 10 g/m2/day). The encapsulation enhances bioactive longevity (60-80% retention during 14-30 days) but increases the material costs by 20-50%. This review underscores the valorization of agro-industrial by-products and waste upcycling. Even though successful results were achieved in laboratories, there are still significant obstacles in terms of scalability, regulatory approval, mechanical performance, and standardization of biodegradation, which hinder the transition from laboratory success to commercial application. This review has pointed out these challenges and recommended cross-disciplinary research-industry innovation to produce commercially viable vegetable-based active packaging.