Polymeric nanoparticles loaded withBaccharis dracunculifoliaDC essential oil: Preparation, characterization, and antibacterial activity in milk

Eudragit RS100 nanoparticles containingBaccharis dracunculifoliaDC essential oil (N-EO) was developed by the nanoprecipitation method. N-EO presented an average diameter of 151.6 nm, zeta potential (zeta) of +51.7 mV, and encapsulation efficiency of 99.4%. The antibacterial activity of N-EO and free essential oil (EO) was evaluated in BHI broth against Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes,andSalmonellaEnteritidis. No viable cell counts were detected for all strains tested up to 4 hr incubation with EO. The same effect was achieved at 24 hr by the N-EO, suggesting a controlled release of encapsulated EO. The antimicrobial activity was also tested againstL. monocytogenesin milk. Both EO and N-EO lack antibacterial effect in whole milk, while a delayed lag phase was observed in skimmed milk. The N-EO caused no significant lysis of erythrocytes suggesting that it can be safe to eukaryotic cells. Practical applications The results of this work suggest that Eudragit nanoparticles can be suitable carriers for essential oils, maintaining their antimicrobial activities. Nanoparticle encapsulation may be useful for food applications by hiding the intense flavor of EO and providing a controlled release of bioactive components. The reduced activity in milk suggests the interaction between the nanostructures and EO with food components, which merits additional studies.