Application of Combined Far-Infrared Radiation and Air Convection for Drying of Instant Germinated Brown Rice

Shorter drying time and reduced energy consumption for instant germinated brown rice drying were evaluated to ensure that the quality of the final product was not compromised. Energy consumption, moisture content, color, morphology, rehydration, texture and sensory evaluation were determined during drying with a combination of far-infrared radiation and hot air. Far-infrared intensities from 1 to 5kW/m(2) were combined with a 40C temperature and 1m/s air velocity. Drying rate increased with far-infrared intensity, hence reducing the total drying time. The mathematical model was validated by comparing the simulated results with temperature and moisture content to described the drying behavior of instant germinated brown rice (R-2=0.999). The total color difference (E) varied from 2.9 to 4.2. Increasing far-infrared intensity decreased hardness, chewiness and gumminess, but increased the rehydration of instant germinated brown rice. The effective moisture diffusivity increased with the far-infrared intensity varying from 0.39x10(-11) to 3.6x10(-10)m(2)/s. The specific energy consumption at 5kW/m(2) far-infrared intensity was 2.90kWh/kg of water removed, resulting in a 66% energy saving when compared to 1kW/m(2) far-infrared intensity. Practical ApplicationsAs an excellent source of nutrients, germinated brown rice has gained more attention than white rice. However, information on instant rice obtained from germinated brown rice is scarce. An alternative technique about instant germinated brown rice preparation was therefore proposed in this work. This study gives a method for the preparation for instant germinated brown rice, which would be a good choice for production of instant germinated brown rice in the industry.