Soy Protein-Based Edible Film as Packaging: Recent Advances

Growing concerns regarding plastic pollution have accelerated the development of biodegradable and sustainable food packaging materials. Soy protein isolate (SPI) has emerged as a promising renewable biopolymer owing to its excellent film-forming ability, biodegradability, and compatibility with functional additives. However, its high water sensitivity and relatively poor mechanical properties continue to limit its commercial application. Although several reviews on SPI-based films have been published, these studies have primarily focused on fabrication methods, material properties, or active packaging applications separately, with limited quantitative comparison of different modification strategies. This review addresses this gap by critically evaluating recent advances in polymer blending, cross-linking, nanocomposite reinforcement, multifunctional additives, and emerging intelligent packaging technologies, while assessing their effects on film performance and commercialization potential. The reviewed studies demonstrate that these modification strategies improved tensile strength by 25-231% and reduced water vapor permeability by 7.7-40%, depending on formulation and processing conditions. Oxygen permeability reductions of approximately 38% were achieved in silver nanoparticle-Persian gum reinforced systems. Functional additives, including essential oils, plant extracts, and metal nanoparticles, enhanced antioxidant activity with up to 82% DPPH radical scavenging activity and achieved antimicrobial inhibition of up to 99.3% against Staphylococcus aureus and Escherichia coli. Food application studies reported reduced weight loss and delayed browning in fresh produce, approximately 40% lower lipid oxidation in meat products, and shelf-life extensions of 5-10 days. Despite these advances, commercialization remains constrained by moisture sensitivity, production costs, regulatory requirements, and limited industrial-scale validation.