Chitosan/polyvinyl alcohol film loading β-acids/β-cyclodextrin inclusion complex: A shelf-life extension strategy for strawberry

Fabricating food packaging films with multifunction (antibacterial, antioxidant, and controlled-release properties) represents a powerful strategy for extending the shelf life and enhancing the safety of perishable fruits. Herein, chitosan (CS) and polyvinyl alcohol (PVA) composite films were loaded inclusion complex (IC) with different concentrations of β-acids/β-cyclodextrin (β-acids/β-CD) or β-acids/hydroxyethyl-β-cyclodextrin (β-acids/HE-β-CD) inclusion complex. Moreover, the films' physical, chemical, and biological properties were systematically investigated. Satisfyingly, these composite films exhibited excellent mechanical properties and thermal stability. As the concentration of the inclusion complex improved, the hydrophobicity of the functionalized films also enhanced (76.50°–108.59°/110.04°). Furthermore, variations in pH were discovered that it could affect β-acids release from films. A significant enhancement in the antioxidant capacity of films could be clearly observed with increased concentrations of the inclusion complex (from 5.56 % to 72.98 %/73.47 %). Additionally, films expressed outstanding antibacterial activity against Gram-positive bacteria ( S. aureus ) (inhibition zone >10.89 mm), with those loading β-acids/β-CD demonstrating a stronger antibacterial effect than those loading β-acids/HE-β-CD. For the preservation of strawberries – the typical representative of perishable fruits, the films significantly extended their shelf life to eight days. As the content of the inclusion complex of β-acids in the film increased, the weight loss dramatically reduced (39.91 % without film vs. 23.12 % with HE-β-CD@CS/PVA film). Overall, the CS/PVA films loading β-acids/β-CD display remarkable multifunctionality and value as a fresh-preserving packaging material with sustained release performance and notable bioactivity.