Cinnamon essential oil nanoemulsions by high-pressure homogenization: Formulation, stability, and antimicrobial activity

The antimicrobial activity and stability of essential oils are increased in nanoemulsion formulations. One of the main disadvantages of using plant essential oils is their low solubility in water. Nanoemulsion formulations of essentials oils can increase their water solubilities and facilitate their interactions with microbial cell membranes, thereby facilitating cell lysis. In this study, cinnamon essential oil (CEO) nanoemulsions were prepared by high-pressure homogenization, using an orthogonal test design to optimize the preparation conditions. The stability of the nanoemulsions during storage and its antimicrobial activity against various foodborne pathogens were investigated. The results showed that during preparation, the homogenization pressures, oil phase ratio, and content of modified starch can affect the particle diameter of the emulsion. The incorporation of medium-chain triglycerides into the emulsion can significantly enhance the nanoemulsion stability and effectively reduce the particle size of the nanoemulsions. The CEO nanoemulsions inhibited the growth of different microbial strains, although Gram-negative bacteria were more sensitive to these nanoemulsions than Gram-positive bacteria. These results are of considerable significance for the research and innovation of natural food preservatives.