Multifunctional nanocomposite packaging films enabled by tannic acid-modified chitin nanocrystals for fruit preservation

Fruits are highly prone to spoilage and decay during transportation and storage. The development of advanced packaging technologies plays a crucial role in extending the shelf life of perishable commodities. Herein, tannic acid-functionalized chitin nanocrystals (TA@ChNCs) were fabricated by leveraging the excellent properties of tannic acid (TA), which readily undergoes oxidative self-polymerization under alkaline conditions. TA@ChNCs can function as multifunctional nanofillers for the development of chitosan/gelatin bio-based films (CG/TA@ChNCs) with comprehensive performance, including excellent antioxidant and UV-blocking abilities, as well as enhanced mechanical and antibacterial properties. In addition, the moisture content, swelling ratio and water solubility of the prepared CG/TA@ChNCs nanocomposite films were significantly lower than those of the pristine chitosan/gelatin (CG) film. Finally, the CG/TA@ChNCs nanocomposite films were applied to mitigate strawberry decay. Results demonstrated that CG/TA@ChNCs films could significantly retard the weight loss of strawberries and inhibit the reduction in their firmness, thereby effectively maintaining strawberry freshness. Therefore, the fully-biobased CG/TA@ChNCs nanocomposite films, fabricated from sustainable bioresources, provide significant insights for their utilization in the field of active packaging.