Effect of spray drying conditions on physicochemical, functional properties and production yield of malt extract powder

In this study, the influence of various parameters such as inlet air temperature and maltodextrin concentration on physicochemical and functional properties as well as production efficiency of spray dried malt extract powder was investigated. A pilot-scale spray dryer used for drying. Process variables were inlet air temperature and maltodextrin concentration (DE=18-20). Maltodextrin as drying aid in concentrations of 20, 30 and 40% (w/w wet weight of malt extract) was used. Inlet air temperature of 140, 160 and 180 ˚C in a co-current stream was used. In all experiments, atomizer rotational speed, feed flow rate, feed temperature and atomizer air pressure were kept constant at 1800 rpm, 10 ml/min, 30±1˚C and 4±0.1 bar, respectively. The least significant difference between means at p< 0.05 was calculated using on Minitab software. The results indicated by increasing inlet air temperature and maltodextrin concentration, powder production yield, particle size and porosity were increased, while moisture content, water activity, bulk density, tapped density, particle density, hygroscopicity, and color values were decreased. Moreover, powders solubility was positively affected by inlet air temperature and negatively influenced by maltodextrin concentration.