Abstract: The antibacterial peptide brevilaterin was microencapsulated with pectin to achieve slow-release antibacterial properties in foods without inhibition by yeast. The optimal experimental conditions that provided maximum microencapsulation efficiency of 98.27% were determined as follows: pectin concentration 0.8 mg/mL, brevilaterin concentration 0.4 mg/mL, pH 5.5, homogenization speed 3 000 r/min, temperature 50 ℃, and homogenization time 30 min. Observation by scanning electron microscopy (SEM) demonstrated that the microcapsule was spherical in shape. Laser particle size analysis showed that the size distribution was in the range of 0.6–8 μm with an average particle size of 1.8 μm. Infrared spectroscopy suggested no characteristic peaks of brevilaterin, indicating that brevilaterin is successfully microencapsulated. As determined by agar diffusion method, the diameter of the inhibition zone of microencapsulated brevilaterin against Staphylococcus aureus was 10.5 and 13.1 mm greater at 48 and 60 h of culture than at 12 h, respectively, suggesting slow release of brevilaterin from the microcapsule. Microencapsulated brevilaterin at 3 000 AU/g had a better preservative effect on bread than 1 g/kg calcium propionate, indicating that the former shows good application potential in the preservation of bread. In conclusion, microencapsulation broadens the application range of brevilaterin in the food industry.

Key words: antimicrobial peptide; microcapsule; pectin