Preparation and antimicrobial activity of oregano essential oil Pickering emulsion stabilized by cellulose nanocrystals

An effective antimicrobial system was developed by using oregano essential oil (OEO) Pickering emulsion. The Pickering emulsion was stabilized by cellulose nanocrystals (CNCs), which were from microcrystalline cellulose (MCC) by selective oxidization ammonium persulfate. Factors affecting the stability of OEO Pickering emulsions, such as oil/water ratio, CNCs concentration, ionic concentration and pH, were studied and analysed by the measurement of the droplet sizes and Zeta potential. The results showed that the emulsions had good stability at higher CNCs concentration and pH values, or at lower oil/water ratio and salt concentration. In addition, the antimicrobial efficacy of OEO Pickering emulsions against four food-related microorganisms was evaluated by determining the minimal inhibitory concentration (MIC). The results showed that prepared OEO Pickering emulsions could efficiently inhibit the growth of four tested microorganisms by destroying the integrity of the cells' membrane. The research would have a certain leading meaning on the design and use of OEO Pickering emulsions stabilized by CNCs for the delivery of antimicrobial essential oils in the food and other industries.