Acid modified and cellulose nanofiber and oleic acid reinforced high performance starch films for cheese packaging

• Modified potato starch film had lower WVA and better integrity than HPMC film under refrigerated storage. • 0.75% CNF reinforcement increased tensile and seal strength of starch films. • Incorporation of 0.3% OA improved flexibility and transmittance of starch films. • Synergistic effects of CNF, acid and OA reduced WVA and enhanced integrity of starch films. • Cheddar cheese packed by modified starch film had low oxidation and microbial growth during storage. Hydroxypropyl methylcellulose (HPMC) and potato starch films were developed and evaluated to enhance hydrophobicity, heat sealability and other film properties for cheese packaging. HPMC films with hydrophobic coatings and cellulose nanofiber (CNF) or nanocrystal (CNC) reinforcement and starch film gelatinized with acetic acid (AA) were evaluated for reducing water vapor absorption (WVA) and maintaining integrity when packaging cheddar cheese. The starch films were further studied by evaluating the effect of acid type (acetic acid (AA) and citric acid (CA)), CNF, and oleic acid (OA) on WVA, water vapor permeability, and mechanical and heat seal strength. The best performed starch films were then applied to package cheddar cheese and assess quality changes of cheese during 45 days of refrigerated storage (4 °C, 75% RH). Starch films gelatinized with AA showed significantly lower WVA and better stability than HPMC films (P<0.05). CNF (0.75%) reinforcement in starch films enhanced tensile and heat seal strength, while OA increased flexibility and seal strength. Overall, starch films gelatinized with AA or CA with 0.75% CNF and 0.3% OA exhibited the best balance of mechanical and barrier properties. UV–Vis spectra confirmed the benefit of OA for reducing light transmission at 350–500 nm. When packaging cheese for up to 45 days of refrigerated storage, starch films gelatinized with CA and reinforced with CNF and OA maintain excellent integrity and preserved cheese quality by controlling weight loss, surface discoloration, microbial growth, and lipid oxidation, demonstrating strong potential as eco-friendly packaging for highly moist and fat cheese.