Optimizations of Spray Drying Process Parameters for Liquorice ( Glycyrrhiza glabra Linn. ) Extract

The physicochemical properties of powders produced by spray drying depend on some process variables, such as the characteristics of the liquid feed (viscosity, flow rate) and of the drying air (temperature). [...]it is important to optimize the drying process. During spray drying various techniques for producing a free-flowing powder have been proposed: addition of dry ingredients (maltodextrin, glucose, soybean protein, aerosil, sodium chloride, and skim milk powder), scrapping of dryer surfaces, cooling of the drying chamber walls , and admission of atmospheric air near the chamber bottom, allowing transport of the powder to a collector having a low humidity atmosphere. High molecular weight drying aids have high glass transition temperatures so it minimizes sticking. Besides reducing powder hygroscopicity, such agents, normally used for microencapsulation, can protect sensitive food components against unfavorable ambient conditions, mask or preserve flavors and aromas and reduce the volatility and reactivity1. The highest predicted efficiency of the spray drying 67 % was found at air inlet temperature of130 °C together with feed flow rate at 1mL/min. [...]these all parameters must be taken into account for the spray drying in order to avoid problems like stickiness and deposition on the chamber wall.