Enhancing Orange Juice Shelf Life Using Soy Lecithin-Stabilized Lemongrass Essential Oil Nanoemulsions: Formulation, Optimization, and Application.

In this study, a nanoemulsion of lemongrass essential oil was prepared using a formulation comprising lemongrass essential oil (1%-10%), soy lecithin (1%-10%), and water (80%-98%) via ultrasonication. The optimal formulation was selected based on its lowest polydispersity index (0.27) and particle size (187.01 nm), alongside its highest zeta potential (-28.34 mV) and encapsulation efficiency (88.20%). The effects of grape seed oil (0%, 1.5%, and 3% w/w) and Tween 80 (0%, 1.5%, and 3% w/w) on the characteristics of the optimal lemongrass essential oil-lecithin formulation were then evaluated. Based on the same extrema, two optimal samples were selected: one with 6% lemongrass essential oil-lecithin (without grape seed oil or Tween 80) and another with 6% lemongrass essential oil-lecithin, 1.5% grape seed oil, and 1.5% Tween 80. The nanoemulsions were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, and their release profiles, antimicrobial activity, and antioxidant properties were assessed. When the nanoemulsions (0%, 0.2%, 0.4%, and 0.6% w/w) incorporated into orange juice, enhanced antioxidant activity (from 14.38% to 77.38%) and reduced bacterial counts (from 5.13 to 4.10 log CFU/mL at 0.6% concentration). Sensory evaluation after 15 days at 4°C revealed improved taste, aroma, and overall acceptance, with the highest scores for the 0.2% lemongrass essential oil-lecithin sample (without grape seed oil or Tween 80). This method effectively masks essential oil flavors while boosting the juice's nutritional value, stability, and health benefits.