Particle size and bulk density
Spray drying experiments were performed. Maltodextrin
(MD) and liquid glucose (LG) were used and
functioned as drying aids. With these drying aids,
the yield increased (Fig. 1). Results indicated that
yield was increased to 15.7% with liquid glucose
concentration of 10% at 120 °C. The bulk density decreased
with increasing inlet air temperature (Fig. 2).
The bulk density of ginger powders was in the range
480–830 kg/m3
. Particle size of ginger powders increased
with inlet air temperatures but decreased with
increased concentration of maltodextrin and liquid
glucose (Fig. 3). The particle size of ginger powder
was in the range 47 to 84 µm. This increment
often resulted in a rapid formation of a dried layer
at the droplet surface and the particle size was due to
skinning over and case-hardening of the droplets at the
higher temperatures. This leads to the formation of
vapour-impermeable film droplet surfaces, followed
by the formation of vapour bubbles and droplets 8
.