Preparation of Chitosan-Coated Toddalia asiatica (L.) Lam Extract Microcapsules and Its Effect on Coating Antibacterial Properties

Antibacterial microcapsules were prepared using chitosan as the shell material and Toddalia asiatica (L.) Lam extract as the core material. The optimal preparation process for the microcapsules of Toddalia asiatica (L.) Lam extract were determined via orthogonal and single-factor experiments as follows: the mass ratio of Toddalia asiatica (L.) Lam extracts and chitosan (M_T:M_C) was 3.0:1, the pH value of microencapsulation was 7, and the reaction temperature was 50 °C. The M_T:M_C increased, the glossiness of the coatings increased and then decreased, the color difference and roughness of the coatings showed an increasing trend, the transmittance of the coatings decreased, the grade of citric acid resistance decreased, the resistance to ethanol and detergents of the coatings increased, and the fracture elongation of the coating increased and then fell. As the M_T:M_C of microcapsules increased, the antibacterial rates of the coating against Escherichia coli increased first, then decreased, and lastly increased. The trend of the coating against Staphylococcus aureus first increased and then decreased. When the microcapsule M_T:M_C was 3.0:1, the performance of the coating was better, and the antibacterial rates against the two bacteria were 67.14% and 68.39%, respectively. Toddalia asiatica (L.) Lam extracts endow waterborne coatings with antibacterial properties, expanding the application range of waterborne coatings.