Research on pH-responsive antibacterial materials using citral-modified zinc oxide nanoparticles

Abstract

Abstract Objectives With the increasing damage caused by foodborne pathogens to human health and the increasing attention given to healthy diets, novel food antimicrobial agents have been widely studied. Materials and Methods In this study, three different morphologies of citral-modified ZnO nanoparticle antimicrobial materials were prepared, and the citral-modified porous ZnO nanorod antimicrobial materials with the highest loading (60.35%) and the strongest inhibitory effect (MIC=0.2–0.1 mg/mL) were screened through a series of characterization and bacterial inhibition experiments. This novel antimicrobial material has excellent and long-lasting antimicrobial properties. It inhibited Escherichia coli by 100% when stowed at 25 °C and protected from light for 10 d and inhibited the growth of E. coli by 58.17% after being stowed under the same conditions for 60 d. Furthermore, we tested the pH change during 24 h of E. coli growth and the pH responsiveness of the materials. Results The results demonstrated that under the acid-producing condition of E. coli growth, the pH-sensitive imine bond (–CH=N–) formed by the condensation of the amino of functionalized ZnO nanoparticles and citral was hydrolyzed to release the citral, which indicated that the release mechanism of citral in the antibacterial material was pH-sensitive. Conclusions The antibacterial materials in this study have broad application prospects in the field of food production and packaging in the future. Moreover, this study provides a theoretical basis for guaranteeing food quality and safety.