Drying Kinetics of Gum Karaya (Sterculia urens) Using Convective Air Dryer

Abstract

The present study was aimed to investigate the drying kinetics of gum karaya (S. urens). Three grades of gum (I, II, III) were dried using a cabinet-type convective dryer. Particle size equivalent to US Sieve size-6 and air temperatures of 50, 60 and 70°C were used for the drying experiments. The experimental drying data was fitted to Page's model to predict the drying kinetics. Investigations with constant air velocity revealed that for grade-I gum, drying rate constant (k) varied between 0.2744-0.3742 (h-1), for grade-II gum between 0.3208-0.4439 (h-1) and for grade-III gum between 0.4098-0.4639 (h-1). The dimensionless number (n) was always more than 1 and minimum value of the Coefficient of determination (R 2) was 0.967. Increase in air temperature enhanced drying process and drying rate. For each particular temperature, the values of drying rate constant were minimum for grade-I, maximum for grade-III and intermediate for grade-II gum.