Spray-dried rosemary extracts: Physicochemical and antioxidant properties

In this work, spray-dried rosemary extracts were obtained. A 33 Box–Behnken design was followed to evaluate the influence of drying conditions on the contents of chemical markers and “in vitro” antioxidant activity of the powder. Although the dry products lost some of their polyphenols, they still had antioxidant activities (IC50) ranging from 17.6 to 24.8 μg · mL−1. Analysis of variance proved that studied factors and some of their interactions significantly affected most of the quality indicators. The best combination of conditions to use for obtaining dry rosemary extracts with adequate physicochemical and functional properties involves an extract feed rate of 6 mL · min−1, a drying air inlet temperature of 140 °C and a spray nozzle air flow rate of 50 L · min−1.