To augment the functional attributes of pectin and expand its prospective utilization in food preservation, this research explored the enzymatic grafting of resorcinol and 4-hexylresorcinol onto pectin. Structural analysis verified the successful grafting of both resorcinol and 4-hexylresorcinol to pectin via esterification , with the 1-OH of resorcinol and 4-hexylresorcinol and the carboxyl group of pectin functioning as grafting sites. The grafting ratios of resorcinol-modified pectin (Re-Pe) and 4-hexylresorcinol-modified pectin (He-Pe) were 17.84 % and 10.98 %, respectively. This grafting modification notably enhanced the antioxidative and antibacterial properties of pectin. Specifically, DPPH clearance and the inhibition ratio in the β-carotene bleaching assay increased from 11.38 % and 20.13 % (native pectin, Na-Pe) to 41.15 % and 36.67 % (Re-Pe), and 74.72 % and 53.40 % (He-Pe). Moreover, the inhibition zone diameter against Escherichia coli and Staphylococcus aureus rose from 10.12 and 10.08 mm (Na-Pe) to 12.36 and 11.52 mm (Re-Pe), and 16.78 and 14.87 mm (He-Pe). Additionally, the application of native and modified pectin coatings effectively impeded pork spoilage, with the modified pectins demonstrating a more potent effect. Among the two modified pectins, He-Pe exhibited the most significant enhancement in pork shelf life.
In this study, hexylresorcinol calix[4]arene-ZnO-Au (HRCA-ZnO-Au) micro–nano materials are synthesized by a simple atmospheric reflux. AuCl4− ions are in situ reduced to Au by the phenolic hydroxyl groups of amphiphilic HRCA and deposited on the primarily formed ZnO sheets, which prevents Zn2+ ions in the solution from depositing at this position. Finally, the flake sample is obtained. HRCA and chloroauric acid effectively shape the morphology of ZnO from micron-sized flowers to nanometer sheets, and they significantly increase the specific surface area of the sample. Low temperature calcination of the HRCA-ZnO-Au composite micro–nano materials partially removes calixarene molecules and exposes the surface of ZnO–Au. Thus, the photocatalytic activity of ZnO–Au is significantly improved due to the synergistic effect between ZnO and Au.
危险品化学品经营许可证（带存储）