Optimized aqueous extracts of maqui (Aristotelia chilensis) suitable for powder production

The aim of this work was to obtain powders rich in bioactive compounds from maqui berry aqueous extracts by spray drying. First, the process parameters of the maqui aqueous extraction were optimized. The optimal operating conditions were found using an experimental Box-Behnken design with three factors: solvent/fruit ratio (2:1, 3.5:1 and 5:1), extraction temperature (25, 50 and 75 °C) and extraction time (30, 75 and 120 min). Soluble solids content, monomeric anthocyanin content (ACY), total polyphenol content (TPC) and antioxidant capacity in the liquid extracts were analyzed as key responses to find the optimal extraction conditions. Secondly, the best aqueous extract (solvent/fruit ratio = 2:1; extraction temperature = 75 °C and extraction time = 75 min) was subjected to spray drying. The effects of different drying adjuvants (maltodextrin, colloidal silicon dioxide, arabic gum, and microcrystalline cellulose) on the powders flow properties, the process yield (PY), the bioactive compounds content and the superficial color were studied. The product based on colloidal silicon dioxide presented the best powder properties: excellent flowability (α: 30.4 ± 0.7°, CI: 8.0 ± 1.7%), adequate moisture content (4.9 ± 0.3%), very good PY (70 ± 1%), high ACY (1528 ± 41 mg cy-3glu/100 g of powder) and TPC (3936 ± 132 mg GAE/100 g of powder), and a purple hue. This maqui powder offers valuable properties that allow its use, among other applications, as a functional ingredient, natural colorant and nutraceutical product.