An Experimental Study On Osmotic Dehydration And Combined Drying Of Beans

Some experiments of the green beans have been done under different conditions in the salt solution penetration according to the principle of osmotic dehydration in the paper. By single factor experiment, analyzes each factor’s influences such as the tackling (such as blanching it in boiling water) or not and cutting into shreds or not on the effect of dehydration. The results showed that blanching can embarrass osmotic dehydration’s effect; cutting into shreds or not can largely affecting the rate of water loss.’And the law is also differently cutting into shreds or not dehydrated at different temperatures. Considering the energy consumption, cutting into shreds was in favor of the rate of water loss, it was showed that the organizational structure of materials was the main factors which affect the osmotic dehydration’s effect. The rate of water loss and the rate of solids increase increased with the increased permeate concentration in the process of osmotic dehydration. High temperature is not conducive to the osmotic dehydration’s effect. Shredded green beans penetration at25℃room temperature have the best effect on the osmotic dehydration. Hot air drying method for further dehydration after the osmotic dehydration of green beans, Green beans, hot air drying after osmotic dehydration shortened the drying time of about2hours, improved the quality of the products and rehydration. Hot air drying experiment with different temperature and wind speed after the osmotic dehydration of green beans, the result is that wind speed was greater impact on the drying rate and the temperature was greater impact on the quality of the products. Hot air drying temperature should not be too high, so70℃is appropriate. Comparing the experimental data under different wind speed and temperature, hot air drying stage with three thin-layer drying mathematical models, the best model is Page equation.