Total phenolics, anthocyanin profile and antioxidant activity of maqui, Aristotelia chilensis (Mol.) Stuntz, berries extract in freeze-dried polysaccharides microcapsules

Abstract

The effect of different polysaccharides combinations on the stability of maqui extract was studied in order to design functional foods, dietary supplements or natural colorants. Encapsulation by freeze-drying using maltodextrin, gum Arabic and inulin at 10, 20 and 30% was performed and phenolics, anthocyanin, antioxidant capacity and color difference of the microcapsules were determined. The stability of the bioactives after 60 days storage at 25 degrees C was also evaluated, along with analysis of a(w), adsorption isotherm, and microstructure to characterize the powders. 10% encapsulating polysaccharide produced best results, with maltodextrin leading to highest process efficiency, while the mixture of maltodextrin/inulin in equal proportion led to highest retention of polyphenols (91.1%) and anthocyanin (98.8%) during storage. The inulin microcapsules retained 94.1% of its antioxidant capacity compared to 25.3% for the freeze-dried maqui powder. Concentration level and polysaccharide matrix of encapsulating agent significantly affect retention of bioactives in the microcapsules.