In this research, date powder was produced by drying aids including Tween 80, pectin, and whey protein concentrate (WPC) at different pH values (5.0, 6.5, 8.0, and 9.5) and using a spray drier at different temperatures (160, 170, 180, and 190 degrees C); then moisture content, solubility, hygroscopicity, bulk density, and total phenolic compounds (TPC) were determined and their correlation with structural characteristics of date powder was analyzed by Taguchi method. Interactions of pectin-surfactant, and pectin-WPC were more effective on moisture and bulk density of date powder, respectively. Although hygroscopicity of different treatments was in narrow range of 25-29%, temperature had the highest impact on TPC; beyond 170 degrees C, TPC of date powder decreased. Treatment No. 7, with the highest WPC level and pH values of 5, maintained the highest TPC content (701 mg 100 g(-1)) in date powder. SEM images revealed that pH = 9.5 and lower temperatures led to smaller particles. (C) 2019 Elsevier B.V. All rights reserved.