Formulation, characterization, and stability of food grade oil?in?water nanoemulsions of essential oils of <i>Tasmannia lanceolata</i> , <i>Backhousia citriodora</i> and <i>Syzygium anisatum</i>

Oil-in-water nanoemulsions were formulated using sunflower oil mixed with each of the essential oils Tasmannia lanceolata (Tasmanian pepper leaf [TPL]), Backhousia citriodora (lemon myrtle [LM]) and Syzygium anisatum (anise [AM]) stabilized Tween 80 ultrasonication. An oil-surfactant ratio 3:1 was found to produce lowest emulsion droplet sizes 96.6 nm for LM, 122.2 AM 131.8 TPL. Increase in surfactant concentration above 10r resulted larger sizes, 165.8–2,647.2 LM (radius, r = .82), 153.7–2,573.5 (r .93) 157.4–2,621.6 TPL .83). Sonication 3 min produced smaller size; however, sonication 9 increase size by 1.48, 1.43 1.47 times .83), respectively. A positive correlation between amplitude (20–50%) .93), .98) .95). showed broad- spectrum antimicrobial activities against yeasts bacteria. The minimum inhibitory (MIC) fungicidal (MFC) weak-acid resistant 0.001–0.003 0.002–0.007 mg/ml nanoemulsion 0.003–0.014 0.005–0.027 stability activity confirm their potential application as food preservatives especially beverage products that are commonly spoiled yeasts.