According to the result of Box-Behnken technique of optimization
by specifying the process responses as color, rehydration ratio
and textural qualities of products, the optimal processing conditions
for WRR, MWL and HAT were 1.44, 499.8 W and 89.99 C
respectively with 88% overall desirability. MWL was found to be a
remarkably key effect on all the process responses. The microscopic
images of products illustrated that microwave drying at 595 W
caused the puffing or volume expansion of the rice structure
leading to greater porosity than that of microwave drying at 255W.
The more porosity occurring at high MWL was expected to be the
vital cause of preferable characteristics of instant brown rice.