Sustainable preservation of cakes: A critical review of protein-polysaccharide edible films, nanotechnology integration and commercial barriers

Protein–polysaccharide edible films represent a sustainable alternative to petroleum-derived packaging for cake preservation, integrating mechanistic functionality with commercial feasibility. Recent advances in solution casting, dip-coating, and nano-enabled fabrication (e.g., ZnO nanoparticles, nanocellulose, and essential oil nanoemulsions at 0.5–5 wt%) have achieved up to 70 % reductions in water vapour permeability, enhanced oxygen barrier properties, and improved antifungal activity in high-moisture bakery systems. Quantitatively, ZnO-incorporated protein films (1–5 wt%) lowered WVP from 19.53 × 10⁻³ to 9.23 × 10⁻³ g/m²·h·Pa, while chitosan nanocomposites reduced WVP from 8.27 × 10⁻⁷ to 1.96 × 10⁻⁷ g/m·h·Pa, delaying fungal growth onset from 3 to 15–22 days under ambient storage. Antioxidant-enriched whey protein films supressed lipid oxidation (hexanal < 0.3 mg/kg) and maintained sensory stability for 14 days. Structural and functional characterization employed FTIR, SEM, XRD, WVTR, and tensile strength analyses, linking formulation variables to preservation outcomes. Optimized composites decreased moisture loss by 30–60 %, improved tensile strength (8–90 MPa), and reduced oxygen permeability by >90 %, extending shelf life two- to threefold. Despite these advances, hydrophilicity, limited heat-sealability, and scale-up constraints remain critical barriers. Future work should prioritize extrusion and roll-to-roll technologies, multilayer architectures, and real-food shelf-life validation to enable industrial translation.