Hydrophobic modification of chitosan-carrageenan film with cinnamon essential oil Pickering emulsion: Improving mechanical properties and fresh-keeping effect on blueberry

In response to the growing demand for sustainable active packaging materials, the carrageenan-chitosan-based emulsion films with different amounts of cinnamon essential oil Pickering emulsions (CPEs) were prepared in this study. Scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy showed that the CPEs were uniformly distributed in the film-forming matrix, with excellent matrix compatibility to form a dense film. When 500 μL CPEs were added, the carrageenan-chitosan film (CF 500 film) showed the highest tensile strength (11.13 Mpa) and elongation at break (14.55%), the lowest water vapor permeability (1.48 g·Pa −1 ·cm −1 ·s −1 ) and oxygen permeability (1.70 g·Pa −1 ·cm −1 ·s −1 ). In the blueberry preservation experiment, after storage for 9 days, the blueberries in the CF 500 film group had a lower weight loss rate (25.59%), and higher total soluble solids content (13.53%), titratable acidity (0.41%), ascorbic acid content (19.46 mg/100 g) and anthocyanin content (0.57 mg/g). In addition, the superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activity of blueberries in the CF500 film group were the highest, which were 62.37 U/g, 196.22 U/g and 5.48 U/g higher than those in the control group, respectively, which was beneficial to delay the senescence and spoilage of blueberry. This study provides an effective strategy for the design of carrageenan-chitosan composite active packaging with high basic properties and strong antibacterial ability.