Microencapsulation of freeze concentrated Ilex paraguariensis extract by spray drying

Concentrated extract of mate leaves obtained from the third stage of the freeze concentration process was microencapsulated with maltodextrin by spray drying. The effect of maltodextrin concentration (20%, 30%, and 40%) on the phenolic compounds, antioxidant activity, microencapsulation yield, morphology, particle size, moisture content, water activity, dissolution, hygroscopicity, color and thermal properties were investigated. The retention of phenolic compounds after microencapsulation by spray drying and the stability of the microcapsules at 4 degrees C for 45 days were also determined. It was possible to note an enhancement of the total phenolic content and antioxidant activity of mate leaves aqueous extract obtained through freeze concentration. The high concentrations of maltodextrin in the microcapsules promoted higher phenolic compounds microencapsulation yield, higher particle size and longer time required for the powders to dissolve in water, while moisture content, water activity and hygroscopicity decreased. The color parameters indicated that maltodextrin protected the microcapsules against heat during spray drying. The results of the thermoanalyses suggested an increase in the stability of the microcapsules. Besides, the microcapsules produced with maltodextrin showed better retention and enhanced stability at 4 degrees C for 45 days. (C) 2014 Elsevier Ltd. All rights reserved.