Preparation, structural characterization, and antioxidant activity of polysaccharide chitosan films from Porphyra haitanensis

Porphyra haitanensis polysaccharide-chitosan (PHP-CS) films were prepared by combining PHP and CS used the casting method with CaCl2; the structure, and physical and chemical properties of the film were studied by rheometry, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), light transmittance, scanning electron microscopy (SEM) and other means. The results indicated that the tensile strength of the PHP-CS film after formation was 5.63 +/- 0.11 MPa, which was due to the interaction between the negative group in PHP and the positive group of CS under the action of hydrogen bonding and van der Waals forces. XRD and SEM results showed that there was a crystal structure in PHP-CS films, which was due to the combination of sulfuric acid group, amino group of CS and CaCl2 in PHP. Importantly, PHP-CS films had strong UV-blocking properties and high thermal stability. In addition, PHP-CS films had stronger oxidation resistance than PHP and CS. Therefore, PHP-CS film has wide application potential in food preservation and packaging.