Effect of spray drying and drying aids on bitter gourd juice powder properties

The spray drying conditions i.e. inlet air drying temperature and drying aids concentration and their effect on physical properties of bitter gourd juice powder was studied. A pilot-scale laboratory spray dryer was used for drying operation. Bitter gourd juice was fed into the drier at different inlet air temperatures of 140, 150 and 160°C with 30% each of maltodextrin, gum arabic and mixture of both maltodextrin (15%) and gum arabic (15%) as drying aids. The powders were analyzed for moisture content, water activity, pH, bulk density and solubility. The results showed that, by increasing inlet air temperature, moisture content, water activity and bulk density decreased, while solubility increased. Moisture content and water activity were significantly affected by the maltodextrin concentration whereas bulk density and solubility were negatively influenced by maltodextrin concentration. Overall, increasing inlet air temperature and maltodextrin concentration led to reduced stickiness and increased powder yield.