Microencapsulation of betacyanin from dragon fruit peel by complex coacervation: Physicochemical characteristics, thermal stability, and release profile of microcapsules

Abstract

Dragon fruit peel contains phytochemicals and natural pigment betacyanin. The crude extract was extracted from the freeze-dried dragon fruit (Hylocereus undatus) peel powder using ultrasonication and betacyanin was isolated by aqueous two-phase extraction. The pigment betacyanin extracted from the dragon fruit peels, was encapsulated using the complex coacervation technique. For encapsulation, four distinct carrier agents, namely maltodextrin, gum arabic, xanthan gum, and gelatin were mixed with sodium alginate to form the wall materials. The betacyanin microcapsule using gum arabic as the wall material had the highest encapsulation efficiency (92.265%), followed by maltodextrin (88.365%), xanthan gum (84.655%), and gelatin (80.526%). The hygroscopicity, swelling index, and solubility of the formulated four betacyanin microcapsules were in the range of 7.581–9.462 g/100 g, 120.155–153.545%, and 54.645–65.216%, respectively. The thermal stability of four microcapsules treated at 80 °C and pH 7 was revealed to have a half-life period of 55–110 min. The release behaviour of microcapsules in terms of betacyanin content in simulated gastric juice were fitted with Higuchi, Korsmeyer-Peppas, Weibull, and Peppas-Sahalin models. The findings support the concept that microencapsulation enables the formulation of a stable product containing functional components.