Effects of different antioxidants on the properties of pectin-chitosan composite films

This study was designed to prepare a pectin chitosan composite film with antioxidant activity by using citrus pectin and chitosan as raw materials, microcrystalline cellulose and glycerol as plasticizers, and adding four natural extracts in phenols: Catechin powder (CatePD), blueberry powder (BluePD), grape seed proanthocyanidins powder (GrapePD), and citrus flavonoids powder (Citrus flavonoids powder). The results showed that there was no significant difference in the thickness of the composite film with added antioxidants within the range of 0.6%, while the tensile strength and elongation at break showed an increasing trend. The optimal amount of catechin was 0.9%, with a maximum tensile strength of 0.57 MPa and a fracture elongation of 29.15%. For BluePD, GrapePD, and CitrusPD, tensile strength and elongation rate reached their maximum values (0.664 MPa and 39.848%, 0.94 MPa and 29.97%, 1.36 MPa and 44.05%, respectively) at concentrations of 1.2%. Compared with the control film, the pectin chitosan composite film with added antioxidant substances showed a lower water vapor transmission rate, and the barrier properties of composite films with CatePD and BluePD against water vapor were superior to those of the CitrusPD and GrapePD. Additionally, the pectin-chitosan composite films with added antioxidants were superior to the control group in terms of radical-scavenging capability, and the most effective radical radical-scavenging capability optimized at the mass fraction of 0.6%. In conclusion, the addition of antioxidants substances could improve the performance of the pectin-chitosan composite films, providing reference for environmentally friendly and green packaging production in the food industry.