Chitosan films incorporated with berberine: enhanced mechanical, antioxidant, and antimicrobial properties as potential food packaging material

Conventional food packaging films pose significant environmental hazards. Consequently, there has been a burgeoning interest in biopolymers, leading to numerous studies to develop biodegradable and bioactive films suitable for the food packaging industry. In this study, we present a novel environmentally-friendly chitosan-based film incorporating berberine, a bioactive compound abundant in various plants. Before blending with a chitosan solution, berberine chloride’s water solubility was enhanced using 2-hydroxypropyl-β-cyclodextrin. Fourier transform infrared spectroscopy confirmed the interactions between berberine and chitosan. Scanning electron microscopy and atomic force microscopy analyses demonstrated the even distribution and good compatibility of berberine within the chitosan film. By blending berberine with chitosan, the obtained biopolymer film exhibited improved mechanical properties compared to the control film. Differential scanning calorimetry analysis showed that berberine incorporation reduced the glass transition temperature from 89 °C to 68 °C. The film also blocked the UV light almost 100%. The addition of berberine decreased the water vapour permeability of the chitosan film while increasing the swelling ratio and water solubility. The berberine-incorporated chitosan film exhibited an antioxidant capacity of 33.7% as measured by the 2,2 diphenyl-1-picrylhydrazyl assay, which was significantly higher than that of the chitosan film, which has 5.92%. The film also demonstrated antimicrobial activity with a reduction in B. cereus and S. typhimurium growth compared to the control. Additionally, the degradation study revealed that the film degraded by 82.5% within ten days under soil. Our findings suggest that the chitosan-berberine film holds promise for applications in the food packaging industry.