Mango leaves (Mangifera indica), an underutilized residue, represent a promising source of functional proteins with potential applications in emulsion-based delivery systems. Leaf protein concentrate (LPC) was extracted and modified by high-intensity ultrasound (HIU) to enhance its techno-functional properties. The modified protein was subsequently used as a natural emulsifier to develop oil-in-water (O/W) emulsions enriched with Curatella americana leaf extract, a phenolic-rich source of antioxidant bioactive compounds. Ultrasound-assisted emulsification (UAEm) conditions were optimized using a Box–Behnken experimental design, evaluating the effects of protein concentration (0.5, 1, and 1.5%), oil-to-water ratio (1:4, 1:4.5, and 1:5, mL:mL), and sonication time (2.5, 5, and 7.5 min) on droplet size (D4,3, µm). The optimized formulation consisted of 1.5% protein, an O/W ratio of 1:4 mL, and a time of 7.5 min, producing an emulsion with a droplet diameter of 7.23 µm. The emulsions exhibited high resistance to storage, pH variation (2–10), ionic strength (100–500 mM NaCl), and thermal treatments up to 50 °C. Additionally, incorporating C. americana extract enhanced thermal stability, photostability, and antioxidant retention under UV exposure, suggesting the formation of reinforcing protein–polyphenol interactions. These findings demonstrate the potential of mango leaf protein as a sustainable emulsifier and protective carrier for sensitive bioactive compounds, supporting its application in functional food and nutraceutical formulations.
Inda-Alcalá et al. (Fri,) studied this question.