洋葱微波干燥特性研究

Microwave Drying Characteristics of Onion

研究不同微波功率下洋葱的干燥特性。结果表明:与热风干燥相比,微波干燥所需时间短,在119W和231W条件下干燥时间分别是80℃热风干燥时间的0.35倍和0.125倍;当微波功率大于385W时,洋葱发生褐变,且功率越高,褐变越严重;功率为119W和231W时,洋葱基本不发生褐变。复水实验表明:功率为119W和231W时,洋葱的复水比高,其复水比分别为4.87和4.67。洋葱微波干燥过程主要处于恒速期,其数学模型符合Page方程。

The aim of the present study was to investigate the drying characteristics of onion under varying microwave powers.The results showed that much shorter length of time was required for microwave drying when compared to hot air drying.The lengths of time required for microwave drying at 119 W and 231 W powers were 0.35 times and 0.125 times shorter than those required for hot air drying at 80 ℃.Under the condition of microwave power 383 W,onion began to become brown.Under the condition of microwave power above 385 W,increasing microwave power could result in more serious brown of onion.However,under the conditions of 119 W and 231 W,brown phenomena rarely occurred.In addition,the rehydration ratios of onion under 119 W and 231 W were 4.87 and 4.67,respectively,higher than those under other microwave powers.The microwave drying of onion proved to be a constant speed process and its mathematical model was in line with Page equation.