Abstract:
This study explored the impact of enzymatic grafting modification on the structure and functional properties of pectin, aiming to provide a scientific foundation for the development of novel food packaging materials with bioactive properties. Using lipase as a catalyst, p-hydroxybenzoic acid and gallic acid were grafted onto pectin molecules. The structure of the modified pectin was characterized using
1H NMR, FTIR, and XPS analytical techniques, and its antioxidant and antibacterial activities were evaluated. The results showed that the grafting rates of p-hydroxybenzoic acid-modified pectin (Hb-Pe) and gallic acid-modified pectin (Ga-Pe) reached 21.8% and 22.9%, respectively. Notably, compared to unmodified pectin, Ga-Pe exhibited significantly (
P<0.05) enhanced DPPH free radical scavenging capacity (69.6%) and
β-carotene bleaching inhibition capacity (65.5%), while the improvement in antioxidant activity of Hb-Pe was limited, with the two indicators being only 5.54% and 28.6%, respectively. Furthermore, the inhibition zone diameters of the two modified pectins against
Escherichia coli and
Staphylococcus aureus were 15.7, 13.3 mm (Hb-Pe) and 16.6, 12.6 mm (Ga-Pe), respectively, which were significantly (
P<0.05) higher than those of unmodified pectin. This study confirms that enzymatic grafting modification can effectively enhance the bioactivity of pectin, providing a new approach for extending the shelf life of food products.