Valorization of tea processing wastewater into multifunctional chitosan-based films for active food packaging

Food spoilage calls for sustainable packaging solutions. In this study, a green strategy was developed by incorporating tea processing wastewater (TPW) into chitosan (CS) films, thereby enabling the valorization of agro-industrial by-products. Owing to its high polyphenol content, TPW markedly improved the functional properties of the composite films. The results showed that TPW incorporation provided excellent UV-blocking ability (UVT ≈ 0%), strong antioxidant activity (DPPH radical scavenging rate of 80.86%), and high antibacterial efficiency (>90%), despite a slight decrease in mechanical strength. Practical application tests further confirmed that the films effectively extended the shelf life of strawberries and beef. Overall, this work provides a cost-effective approach for developing multifunctional active packaging by combining the film-forming capacity of CS with the bioactivity of TPW, thus contributing to the circular bioeconomy.