Moisture content and water activity
Moisture content varied from 1.69 to 8.53 g/100 g (Table 1) and
the sample treatment of process condition of 70 C and feed rate
7 g/min differed significantly (P < 0.05) from the other treatments.
This similar result was observed for water activity. The lowest
water activity value was observed for the uncoated sample, this
means that powders absorbed water during coating under the
process conditions in the fluid bed chamber. Water activity is an
important factor that influences the storage of powders. Moisture
content allows the growth and development of microorganisms
and biochemical reactions. Dried powders developed with a water
activity lower than 0.6 are considered to be safe for general storage
(Chiou & Langrish, 2007; Kha et al., 2010). Water activities in this
study ranged from 0.117 to 0.423 (Table 1).