Abstract
Spray-drying technique is widely used in the production of powder from fruit juices. Carrier type and inlet temperature are two major factors that influence drying efficacy and powder quality. In this study, barberry juice (Berberis vulgaris L.) was powdered using 12% (w/v) maltodextrin with 4-7 and 16.5-19.5 dextrose equivalents (DEs) at two different inlet temperatures at 130 and 150 °C. Moisture content, bulk density, hygroscopicity, color, total anthocyanin content (TAC), microstructure, glass transition temperature and the X-ray diffraction of the prepared powders were investigated. The inlet temperatures and the utilization of maltodextrin with different DEs as the carrier agent, had different effects on the physicochemical properties of the prepared powders. By increasing the inlet temperature, the moisture content decreased while hygroscopicity increased. At inlet temperature of 130 °C, powders prepared with lower maltodextrin DEs had higher moisture content and bulk density, but lower hygroscopicity (p < 0.05). The SEM result demonstrated that, a decrease in color of the powder by increasing the inlet temperature. Darker particles with higher a* values and total anthocyanin contents (4.68 mg/g) were obtained when a larger amount of maltodextrin with lower DEs was utilized. At the lower inlet temperature, the powder particles had smoother surfaces. The glass transition temperature of the powders ranged from 47.1 to 54 °C based on different inlet temperature and DEs as well as moisture content. The amorphous surfaces of the dried particles were verified via X-ray diffraction profiling. Overall, applying different DEs in combination and lower inlet temperature led to the more appropriate physical and functional properties to the barberry powder. The TAC significantly depended upon the carrier agent, the inlet air temperature, and the interaction between the two variables.