Preparation and characterization of chitosan-based edible active films incorporated with Sargassum pallidum polysaccharides by ultrasound treatment.

In this study, Sargassum pallidum polysaccharides (SPPs) were incorporated into chitosan (CH) to develop a novel edible active film (CH/SPPs-US) via ultrasonication. The mechanical, water vapor permeability, surface morphology, crystallinity, antioxidant, and fruit preservation properties of CH/SPPs-US films prepared under sequences of matrix ratios and ultrasound treatment were investigated. The results revealed that the addition of SPPs combined with ultrasonic treatment could significantly enhance the transparency, elongation and tensile strength of the films whereas the water vapor permeability was decreased. Tensile strength and elongation at break of the C2/SP1.2-US film were 12.07 N and 54.18%, respectively, which were significantly higher than those for CH film. Meanwhile, the water vapor permeability value of C2/SP1.2-US was reduced by as high as 40.2% compared with that of chitosan film. In addition, antioxidant effect evaluation showed that the CH-based films added with SPPs exhibited better antioxidant activity than CH film, and ultrasonic treatment could further strengthen the antioxidant activity of the film. The CH/SPPs-US films could effectively extend the shelf life and inhibit the deterioration of the strawberry at room temperature (25 ± 1 °C) and 70% ± 5% relative humidity for 7 days. These results indicated that the CH/SPPs edible films via ultrasonication could be developed as edible packaging films for the preservation of fresh fruits.