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.