Spray Drying~~ One of the Drying Process Method

Spray drying is one of the best drying methods to convert, in a single step, fluid materials into solid or semi-solid particles . Spray drying also becomes more and more important in industries sector such as pharmaceutical and chemical industries. Spray drying is a unit operation that creates a fine spray of liquid product in a hot air environment . Product quality can be preserved in high drying air temperature due to rapid evaporation maintains droplet temperature at low level. The initial liquid feeding can be a solution, an emulsion or a suspension . It also can be apply in heat-resistant and heat sensitive products. In addition, time required to drying of droplet in spray dryer is much shorter than other drying processes.

Spray drying involves complex interactions of process, apparatus and feed parameters which all have an influence on the final product quality .  Low water activity and light weight good quality final fruit powder can be produce in spray drying process, resulting in easier storage, resists microbial growth and transportation. The quality of spray dried fruit powder is dependent on the spray dried parameter which includes inlet temperature, air flow rate, feed flow rate, atomizer speed, types of carrier agent and their concentration. Different operating spray dried parameter used can be strongly affected characteristic of spray dried fruit powder produced such as bulk density, hygroscopicity, solubility, flowability, size of powder and glass transition temperature of powder. Spray drying is often selected as it can process material very rapidly while providing relative control of the particle size distribution.