Double emulsion (W/O/W) microcapsule preparation of novel bacteriocin lactococcin036019 with synergistic compound vitamin C prolongs the antibacterial activity in food matrix

Application of bacteriocins in food preservation encounters the issue of activity impairment. This study intends to find a comprehensive solution to the enhancement of bacteriocin activity. Firstly, several food matrices were found to significantly reduce the antibacterial activity of bacteriocin lactococcin036019. Subsequently, vitamin C and carvacrol were both found to display a synergistic effect with bacteriocin against Staphylococcus aureus. Thereafter, double emulsion containing lactococcin036019 and vitamin C was successfully prepared. Spray drying of double emulsion with lactococcin036019 and vitamin C resulted in microcapsule powder with the particle size and entrapment efficiency of 9.10 μm and 56.18%, respectively. This microcapsule powder reduced S. aureus number by around 5 lg cfu/mL at 24 h and displayed continuous antibacterial activity in soymilk. Besides, the microcapsule powder with bacteriocin and vitamin C showed remarkable stability during storage. The double emulsion microcapsules prepared in this study demonstrate great potential in long-term preservation of food.