EVALUATION AND SELECTION OF THIN-LAYER DRYING MODELS FOR DRYING KINETICS OF GRATED COCOS NUCIFERA USING TRAY DRYER

Coconut (cocos nucifera) is an essential resource for food, shelter, fuel and even medicine. Modern design engineering and technology are employed to develop high quality exportable coconut products. Drying is a cost-effective method of food preservation which involves simultaneous heat and mass transfer. In this study, the hot air convective thin-layer drying behaviour of grated cocos nucifera were evaluated in a laboratory scale tray dryer. Drying experiments of grated cocos nucifera with the bed height of 0.2, 0.4 and 0.6cm were conducted at air temperatures of 35, 45 and 55°C and with drying air velocities of 1, 2 and 3 m/s. The drying curves begins with the falling rate period and contained no constant rate period. It was concluded that drying rate increases with increasing air velocity and temperature, and decreased with an increase in the bed height. The optimal drying condition is at temperature of 55℃, air velocity 3m/s and 0.2cm bed height. Additionally, the mathematical models describing the thin layer drying curves were compared by non-linear regression analysis. Eight different thin layer mathematical models is compared according to statistical parameters correlation error (R), standard error (SE) and reduced chi-square (