Double Nanoemulsion Loading Betalains Extract of Beetroot (Beta vulgaris L.): Ultrasound-Assisted Synthesis, Storage Stability, and Antioxidant Activity

A comprehensive study was conducted to encapsulate hydrophilic betalains from a red beetroot extract through double emulsification. The primary emulsion of water in oil (W/O) was prepared using polyglycerol polyricinoleate (PGPR) at a concentration of 4.0% as a hydrophobic surfactant for the Sacha Inchi oil. This emulsion was created through a combination of magnetic stirring and ultrasonication. Physicochemical characterizations of the double nanoemulsions of betalains (DNB) were carried out to determine the mean particle size, which was measured as 93.8 nm by using DLS and 82.3 nm by TEM imaging. The storage stability of the DNB indicated that color fastness and particle size remained stable within a pH range of 3.0 to 9.0. These values also remained consistent at temperatures up to 90 °C, and the DNB remained stable for 24 days at room temperature and for over 30 days under cold storage conditions. Furthermore, the DNB exhibited high antioxidant activity, as assessed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method.