Encapsulation of natural antioxidants extracted from Ilex paraguariensis

Yerba mate (Ilex paraguariensis) is a beverage traditionally drunk in various countries of South America. It is rich in antioxidant compounds, minerals and vitamins. Aqueous extracts were obtained and characterized by total polyphenols content and antiradical activity. Yerba mate lyophilized extracts were encapsulated with two different systems: calcium alginate and calcium alginate–chitosan. Texture properties of the beads depended on immersion time in CaCl2 and in chitosan solutions. Release of the antioxidants in water was measured to analyze the diffusion and kinetic behavior of the system. Sodium citrate was found to be the most effective agent to disintegrate the beads. FT-IR spectra were useful to confirm the interaction of the two polysaccharides. SEM micrographs allowed to select the best drying method for the beads. Encapsulation of yerba mate extracts in alginate and in alginate–chitosan beads is a promising technique for food supplementation with natural antioxidants.