Fabrication and Characterization of Citric Acid Crosslinked, Sea Buckthorn Leaves Extract Incorporated PVA-Based Films with Improved Antioxidative and UV-Shielding Properties for Food Packaging Applications

The present work demonstrates the fabrication and characterization of bioactive, citric acid (CA) crosslinked polyvinyl alcohol (PVA) film containing sea buckthorn leaves extract (SBLE) and evaluated for its various functional properties. Crosslinking produced highly stable and water-swellable films that were transparent, homogenous, and flexible, demonstrating the compatibility of CA with PVA. The incorporation of SBLE significantly enhanced various functional properties. The chemical structure and interaction among the different components of PVA films were analyzed by using ATR-FTIR spectroscopy. Total phenolic content in the SBLE was found to be 41.20 ± 0.54 mg GAE/g and the yield varies between 46 and 54% based on the dry mass of the dried leaves. SBLE-loaded films exhibit potent antioxidant activity due to the free radical scavenging ability of polyphenolic compounds in the extract, with a maximum value of 66.09% at 6% SBLE. These films also exhibit strong UV-blocking character with utmost transparency. The biodegradability is also enhanced with the addition of SBLE, with around 89% of the film degrading in 35 weeks. Thus, such films containing natural extract could be a potential material for food packaging applications.