Drying Process Development of Instant Rice Product: Effects of Methods and Drying Temperature

Two-step drying of cooked rice during instant rice process yields good quality product. The research aims to study drying methods and drying temperature. The process of drying instant rice with vacuum dried at          a temperature of 90 °C and pressure 80 mbar for the first step of drying. Dried rice from fluidize bed drying and tray drying at temperature of 50, 60 and 70 °C were compared. The parameters considered were shrinkage, gelatinization level, rehydration ratio, texture and color. The results showed that the second step of drying by fluidized bed dryer gave higher gelatinization level and lower shrinkage than drying by tray dryer. Considering       the effect of drying temperature on quality of dried rice it was found that drying temperature at 50 °C resulted in higher gelatinization level and higher shrinkage than those of 60 and 70 °C drying temperature, respectively.              The hardness and whiteness of  instant rice after rehydration  were lower for samples dried by fluidize bed dryer than those by tray dryer. The results implied that second steps of drying by fluidize bed dryer provide better quality of instant rice product. This drying process can be an alternative to produce instant rice in an industrial scale. Keywords : Physical properties,  vacuum drying,  tray drying,  fluidized bed drying, gelatinization