Bio-Interfacial Insights of Nanoparticles Integrated Plant Protein-Based Films for Sustainable Food Packaging Applications

With the advent of sustainable food packaging, biodegradable, edible packaging films prepared from plant-based protein precursors such as zein, wheat gluten (WG), and soy protein isolate (SPI) are gaining influence. However, their inherent brittleness and low mechanical strength limit their practical application. To address this challenge, nanomaterials are incorporated as fillers to enhance physicochemical and functional properties. Metallic and biopolymeric nanomaterials, when uniformly dispersed, substantially improve tensile strength and Young’s modulus. For instance, zinc oxide nanoparticles enhance mechanical strength by 30-70%, nano clays by 40-80%, and biopolymer-derived nanoparticles by 20-50%, depending on dispersion and compatibility. These nanomaterials interact with proteins, modifying film morphology, surface hydrophobicity, and water vapor permeability. Besides, nanoparticles reduce gas permeability, block ultraviolet radiation, and provide antimicrobial and antioxidant properties, extending food shelf life. However, metallic nanoparticles may pose potential toxicity concerns, requiring strict adherence to safety guidelines. With the ultimate goal of developing sustainable food packaging films to prolong the shelf life of food, this review assesses the impact of metallic nanoparticles blended with zein, WG, and SPI films. Finally, the safety assessment of the nanomaterials is discussed, with a highlight on the limitations of existing research, extending into future directions that encompass sustainable synthesis strategies.