Preparation and characterization of Zein‐sulfated Cardamine hupingshanensis polysaccharide composite films

Cardamine hupingshanensis polysaccharide (CHP) was modified by the sulfur trioxide–pyridine method to obtain the sulfated C. hupingshanensis polysaccharide (SCHP) with a substitution degree of 0.72. The spectral results revealed that the sulfate group was successfully introduced to CHP. In the in vitro antioxidant assay, SCHP showed the highest scavenging rate of hydroxyl radicals, ABTS, and DPPH. Different concentrations of SCHP were chosen to form a compound with Zein to prepare novel bioactive films successfully. The functional and characterization studies of the films were also conducted. The scavenging ability of the films for hydroxyl radicals, ABTS, and DPPH was improved by adding different concentrations of SCHP. Although the films showed a decrease in transparency with the addition of 4 mg/ml SCHP, there was an improvement in tensile strength compared to films without the addition of SCHP. These findings indicate that Zein‐SCHP films can be used as a functional food packaging material with antioxidant properties.