Drying characteristics of Garcinia atroviridis

Some physical and chemical properties of fresh garcinia fruits are reported. The most suitable drying conditions for garcinia material in a tray dryer based on the final moisture content were determined by extensive testing. It was found that for the material thickness of 2, 4 and 6 mm, a temperature of 55 °C and air velocity of 1.2 m/s are suitable for drying. The most suitable time where the final moisture content met the commercial standard was found to be 199, 256 and 427 min, respectively. The higher the temperature, the shorter the drying time. It was also observed that the suitable drying time for 2-mm thick material and air velocity of 1.2 m/s was 199, 159 and 99 min for drying temperature of 55, 65 and 75 °C, respectively. Drying characteristics are also reported. Most of the drying rate curves appear in a falling rate period except at low temperature and low velocity of operation parameters i.e. 55 °C and 0.5 m/s for 4-mm thick material, where the constant drying rate is approximately 0.09 kg water/min.m2. The sorption isotherm is sigmoidal shape at 30 °C and monolayer moisture content is 14.78 kg water/100 kg dry solid. Soaking material in 1.5 and 3.0 %w/w sodium chloride did not affect the drying rate. Effective moisture diffusivities were evaluated to be 5.57×10-10, 6.94×10-10 and 1.11×10-9 m2/s at temperatures 55, 65 and 75 °C, respectively