ANALISIS PERUBAHAN KADAR AIR CHIP SINGKONG DAN PERUBAHAN SIFAT UDARA PENGERING SELAMA PENGERINGAN DENGAN TRAY DRYER

Abstract

Cassava is classified as one of tropical plant, but it can adapt and grow well in subtropic area. This plant doesn�t demand spesific condition for its planting. Cassava can be found in many areas in Indonesia, because Indonesia has suitable climate for this plant. The research studies about the change on water content for cassava�s chips when drying process was occured while altering drying temperature in tray dryer and variating sample mass on every treatment. Tray dryer was set in 50oC, 60oC, dan 70oC temperature and on every temperature change different sample mass was used, we took 4 kg, 8 kg, and 12 kg mass. First, we prepared the sample. Cassava was peeled and cleaned with fresh water, then chopped chip like. The research was done under 50oC, 60oC, dan 70oC temperature and on every temperature change we put different sample mass, that was 4 kg, 8 kg, and 12 kg. Sample was dried until it reached specified water content. Before drying, sample was taken to measure starting water content with thermogravimetri method. Next, in every treatment, more water content measurement was taken in every sample. We also took measurement of dryer temperature, humidity ratio, and drying air velocity (including input and output air). Data was taken in every 15 minutes. Decrease on water content was used to determine the drying constant number. The research resulted, that on drying process of cassava chip using tray dryer, mostly falling rate was found in every treatment. Drying rate of cassava chip on tray dryer was affected by mass and drying temperature. Drying rate on 4 kg mass on 50oC, 60oC, dan 70oC temperature were 0,0164 minutes-1, 0,0226 minutes-1 dan 0,0258 minutes-1 consecutively. 8 kg mass reached 0,0141 minutes- 1, 0,0223 minutes -1 dan 0,0171 minutes-1 on 50oC, 60oC, dan 70oC temperature. Last, 12 kg mass was measured at 0,0137 minutes-1, 0,0143 minutes-1 dan 0,0149 minutes-1 on 50oC, 60oC, dan 70oC temperature. Drying efficiency reached 1,69- 5,89%, and heating efficiency of tray dryer hit 12,8004% to 59,6146%. Activation energy (Ea) that needed for drying process on 4 kg, 8 kg, and 12 kg mass were 20,947 KJ/mol, 9,215 KJ/mol, dan 3,866 KJ/mol consecutively. Collision frequency (Ao) that happened on 4 kg mass was 41,1943 and 0,4896 on 8 kg mass, on 12 kg mass it reached 0,0578