Sustained-release antibacterial gelatin films: Effects of diatomite/carvacrol complex on their structure, physicochemical and antibacterial properties

Antibacterial diatomite/carvacrol (D/C) complex was prepared by utilizing diatomite as an effective carrier of carvacrol, and further incorporated into gelatin with different amounts (0-30%, w/w based on gelatin) to develop a series of antibacterial gelatin-based films. D/C complex was found to have appropriate interaction and compatibility with gelatin matrix as revealed by FTIR and SEM analysis. With increasing D/C complex content, light transmission, moisture content, water solubility and tensile strength of the films decreased, whereas elongation at break and water vapor permeability increased. More importantly, an apparent antibacterial effect began to be observed for the film-forming solution containing 10% (or more) D/C complex, and the subsequent film exhibited a much slower release rate of carvacrol towards food simulant (60 wt% glycerol solution) than gelatin film with the same content of carvacrol. Therefore, the developed antibacterial gelatin films with desirable physical and sustained-release properties have great potential for active food packaging applications.