Effect of starch aldehyde-catechin conjugates on the structural, physical and antioxidant properties of quaternary ammonium chitosan/polyvinyl alcohol films

The application of catechin in active packaging films is restricted by the low stability of catechin. In this study, the stability of catechin was elevated by conjugating catechin with starch aldehyde. The obtained starch aldehyde-catechin conjugates were added into quaternary ammonium chitosan (QAC)/polyvinyl alcohol (PVA) blend to prepare active packaging films. The structural, physical and antioxidant properties of QAC/PVA films containing starch aldehyde-catechin conjugates were determined. Results showed starch aldehyde-catechin conjugates formed hydrogen bonding with QAC/PVA film matrices and changed the uniformity of films. After starch aldehyde-catechin conjugates were added into films, the water vapor permeability, tensile strength and elongation at break of films were increased by 2.51%–16.03%, 11.73%–20.15% and 0.78%–12.15%, respectively; whereas the oxygen permeability of films was reduced by 6.67%–53.33%. Starch aldehyde-catechin conjugates increased the 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging efficiencies of films by 852.3%–995.5% and 599.5%–669.3%, respectively. The developed films were used to package peanut oil at 37 °C for 28 days. As compared with oil packaged in QAC/PVA film, oil packaged in QAC/PVA films containing starch aldehyde-catechin conjugates showed significantly lower peroxide values and thiobarbituric acid reactive substance levels. Results suggested QAC/PVA films containing starch aldehyde-catechin conjugates had a good potential in peanut oil packaging.