In the study, the effectiveness of intermittent ( IMWD ) and continuous ( CMWD )
microwave drying and hot air drying ( HAD ) treatments on apple slices were
compared in terms of drying kinetics (moisture diffusivity and activation energy)
and critical physicochemical quality attributes (color change, rehydration ratio,
bulk density, and total phenol content ( TPC ) of the fi nal dried product. The
temperature, microwave power, air velocity, and pulse ratio ( PR ) applied in the
experiments were 40–80°C, 200–600 W, 0.5–2 m/s, and 2–6, respectively. Results
showed that IMWD and CMWD more effective than HAD in kinetic parameters
and physicochemical quality attributes. Also, results indicated CMWD had the
lowest and highest drying time and effective diffusivity. The exponential model
for estimating IMWD activation energy, considering absolute power (1/P) and
pulse ratio were also represented. The color change in apple slices dried by
HAD showed the highest change.
کلید واژگان :
Dried apple , hot air drying , intermittent microwave , microwave drying , phenol compounds , physicochemical properties
