Development and Evaluation of a Convective Type Dryer for Nutmeg mace

Abstract

A convective type nutmeg mace dryer was developed and its performance was evaluated. The major parts of the developed dryer are Drying chamber, Plenum chamber, Heating coil box, Air flow control and Blower with power source. The dryer was evaluated at three different air temperatures of 40 o C, 45 o C and 50 o C and at three air velocities 1.6 m/s, 2.0 m/s and 2.4 m/s. Unblanched samples dried at drying air temperature of 45 o C and with air velocity of 2.4 m/s produced better quality dried mace in terms of volatile oil content, myristicin content, oleoresin content and color. Also at this treatment combination the drying time was lower and the energy consumption minimum. It was also found that the quality of the dried samples in the developed dryer is superior to conventional sun drying method. It was also established from the studies that blanching pretreatment prior to drying by dipping in hot water at 75 o C for 2 min further increased the quality of dried mace. The convective type nutmeg mace drier is simple in construction, efficient in operation and produces better quality mace.