Yerba Mate Extract Encapsulation with Alginate and Chitosan Systems: Interactions between Active Compound Encapsulation Polymers

Abstract

Yerba mate (Ilex paraguariensis) contains a high amount of polyphenols associated with antiradical activity and possible benefits for preventing degenerative diseases. Natural extracts from this South American herb were encapsulated in calcium alginate and calcium alginate-chitosan beads to be incorporated as an additive in food products. The interactions between the active compound and the polymers were evaluated by Scan- ning Electron Microscopy (SEM), thermal analysis (Thermo Gravimetric Assays, TGA, and Differential Scanning Calorimetry, DSC) and Fourier Transform Infrared Spectrometry (FT-IR) studies. Also, the effect of these interactions on extract release in a gastrointestinal model system was evaluated. Results showed the interactions between the calcium alginate matrix and the chitosan external layer. Also, interactions between the natural extract and each polymer were observed. In both encapsulation systems the highest polyphenol content was released in simulated gastric fluid. However, capsules coated with chitosan allowed releasing a higher amount of polyphenols into the simulated intestinal fluid. This fact was attributed to both the protect- tion of the chitosan barrier and the strong interaction between yerba mate extract and chitosan.