Characteristics of cassava drying were investigated by using a microwave hot-air drying system. Two waveguides were installed on a single plane of the microwave cavity. The drying experiments were carried out at two l...Characteristics of cassava drying were investigated by using a microwave hot-air drying system. Two waveguides were installed on a single plane of the microwave cavity. The drying experiments were carried out at two levels of sample surface temperature set-points, 70℃ and 80℃respectively. Cassava (Rayong-9) with 2.5 kg weight and 61% moisture content on wet basis was dried in the dryer for about 300 - 340 minutes until the final values of moisture content of about 20% db were achieved. It was found that the drying time decreased with an increase in sample-surface temperature set point. Approximately 87% of the moisture was removed during the drying period. It was found that there was a rapid decrease in moisture ratio values followed by the gradual decline period in all experiments. With regard to drying kinetics, 5 commonly used mathematical models were examined with the experimental data. It was found that Page’s and diffusion models provided a good agreement between the experimental and predicted moisture ratio values for all temperature set-points. The regression results indicated that highest values of coefficient of determination and adjusted coefficient of determination as well as lowest value of standard error of estimation were reported for the case of Page’s model at 80℃?temperature set-point.展开更多
文摘Characteristics of cassava drying were investigated by using a microwave hot-air drying system. Two waveguides were installed on a single plane of the microwave cavity. The drying experiments were carried out at two levels of sample surface temperature set-points, 70℃ and 80℃respectively. Cassava (Rayong-9) with 2.5 kg weight and 61% moisture content on wet basis was dried in the dryer for about 300 - 340 minutes until the final values of moisture content of about 20% db were achieved. It was found that the drying time decreased with an increase in sample-surface temperature set point. Approximately 87% of the moisture was removed during the drying period. It was found that there was a rapid decrease in moisture ratio values followed by the gradual decline period in all experiments. With regard to drying kinetics, 5 commonly used mathematical models were examined with the experimental data. It was found that Page’s and diffusion models provided a good agreement between the experimental and predicted moisture ratio values for all temperature set-points. The regression results indicated that highest values of coefficient of determination and adjusted coefficient of determination as well as lowest value of standard error of estimation were reported for the case of Page’s model at 80℃?temperature set-point.
