Quaternary ammonium chitosan-based active packaging films incorporated with dialdehyde guar gum-proanthocyanidins conjugates: Characterization and application in the edible coating of pork

In this study, antioxidant and antibacterial proanthocyanidins (PA) were covalently conjugated with dialdehyde guar gum (DGG) to produce DGG-PA conjugates. Then DGG-PA conjugates were incorporated into quaternary ammonium chitosan (QAC)-based matrix to create QAC/DGG-PA films. The structure, physicochemical properties, and antioxidant and antibacterial effects of DGG-PA conjugates and QAC/DGG-PA films were analyzed. The active packaging potentials of QAC/DGG-PA film-forming solutions in the edible coating of pork loins were evaluated. Results showed DGG-PA conjugates had unique UV absorption peak (280 nm), infrared bands (1610 and 1521 cm−1) and proton nuclear magnetic resonance signals (6.82 ppm) of PA groups. DGG-PA conjugates showed amorphous state with sheet-like and fibrous morphology. DGG-PA conjugates had good biocompatibility and antioxidant and antibacterial effects. After adding DGG-PA conjugates, the surface of QAC-based films became smooth and the crystallographic nature of the films declined. DGG-PA conjugates elevated the light/water vapor/oxygen barrier performances, mechanical properties, and antioxidant and antibacterial effects of QAC-based films. QAC/DGG-PA edible coatings effectively prolonged the shelf life of pork loins from 4 days to 6−10 days. Results verified QAC/DGG-PA films and their film-forming solutions had good application potentials in active packaging. [Display omitted] •Proanthocyanidins (PA) were covalently conjugated with dialdehyde guar gum (DGG).•DGG-PA conjugates had good biocompatibility, antioxidant and antibacterial effects.•Films were prepared using quaternary ammonium chitosan (QAC) and DGG-PA conjugates.•Conjugates increased the antioxidant and antibacterial effects of QAC-based films.•QAC/DGG-PA film-forming solutions showed good edible coating effects on pork loins.