Nanoemulsions of oregano essential oil and green extracts: Characterization and application in whey cheese

The aim of the present study was the selection of an appropriate system for the delivery of bioactive compounds from oregano essential oil and extracts and their incorporation in two whey cheeses. For this purpose, oil-in-water (O/W) nanoemulsions were prepared by ultrasonication as delivery systems. The droplet size distribution and the microstructure of the nanoemulsions were analyzed using laser diffraction analysis and confocal laser scanning microscopy, respectively. In addition, the antifungal activity of nanoemulsions was assessed against Penicillium expansum both in vitro and in whey cheese. The results showed that the combination of oregano essential oil and extracts produced nanoemulsions with potent antioxidant and antifungal activity against P. expansum in vitro. In addition, the nanoemulsions presented antifungal activity against P. expansum after application in whey cheese and, in some cases, extension of whey cheese shelf life was reported. The sensory analysis showed that nanoemulsions of oregano affected the organoleptic profile of both types of whey cheese.