Microcapsules of a cinnamon, peppermint, and lemon essential oil mix by spray drying: Preparation, characterization and antibacterial functions

Plant essential oils (EO) are increasingly used as food preservatives due to their antibacterial and antioxidant activities . For such applications, EO are commonly microencapsulated to overcome their poor stability, low solubility and dominant aromas. But, typically, individual EO act against only a narrow range of bacterial species. Therefore, in this study, we aimed to develop a microencapsulated preservative using a combination of three EO and to determine its anti-bacterial action against three common food contaminants, viz. Escherichia coli , Salmonella and Staphylococcus aureus , and one, usually, beneficial species, viz. Lactoplantibacillus plantarum . The EO of cinnamon ( Cinnamomum cassia ), peppermint ( Mentha haplocalyx ) and lemon ( Citrus limon) were combined in the proportions, 1.0 : 1.8: 2.4, respectively and were encapsulated in gelatin-chitosan by spray drying. The particle size, zeta potential , moisture content, and encapsulation rate of the essential oil microcapsules (EOM) were measured. With increasing EOM exposure time, the concentrations of E. coli , Salmonella , S. aureus and L. plantarum decreased by 3, 3, 4, and 5 orders of magnitude, respectively. Cell apoptosis accompanied loss of membrane integrity and permeability, inhibition of lactate dehydrogenase activity and disruption of organic acid metabolism. Gram-positive bacteria ( S. aureus and L. plantarum ) were more susceptible to those effects of EOM than Gram-negative bacteria ( E. coli and Salmonella ). It also demonstrates that in applications as preservatives for probiotic foods requiring live L. plantarum , EOM comprising cinnamon, peppermint or lemon EO should be avoided.