Influence of Freeze- and Spray Drying with Carrier Agents on Alkamides, Antioxidant Properties, and Process Contaminants in Echinacea purpurea Root Extract Powders

<i>Echinacea purpurea</i> (L.) Moench root is a rich source of alkamides and other bioactive compounds with potential health-promoting effects. This study aimed to evaluate the influence of drying technique and carrier type on alkamide content, antioxidant properties, and process contaminants in <i>E. purpurea</i> powders. Root extracts were subjected to freeze-drying or spray drying at air inlet temperatures of 150, 170, and 190 °C, with maltodextrin, pea protein isolate, or their blend used as carrier agents. The resulting powders were analyzed for physical and chemical properties, including alkamides concentration, total phenolics content, antioxidant capacity, free amino group levels, and markers of advanced Maillard reaction products. Spray-dried powders had a moisture content lower than 2.3%, compared with an average of 7.7% in freeze-dried samples. Spray drying at 150 and 170 °C combined with the maltodextrin-pea protein blend resulted in the highest alkamide levels, while total phenolics content and antioxidant capacity were retained at levels comparable to freeze-drying. Neither hydroxymethyl-<i>L</i>-furfural nor furfural was detected via HPLC in any sample. Overall, spray drying under the tested conditions represents a favorable alternative to freeze drying, yielding <i>E. purpurea</i> root extracts powders with higher alkamides content, similar antioxidant properties, and absence of process contaminants.