高水分玉米微波干燥特性及对加工品质的影响

MICROWAVE DRYING CHARACTERISTICS OF HIGH-MOISTURE MAIZE AND THE EFFECT ON PROCESSING QUALITY

运用微波干燥试验系统,在不同的干燥功率、干燥时间,对不同水分含量的玉米进行微波干燥,研究玉米微波干燥特性及对玉米加工品质的影响.结果表明:玉米微波干燥过程可分为3个阶段:预干燥阶段、恒速干燥阶段和降速干燥阶段,而微波干燥主要处于恒速干燥阶段,不同的初始水分含量其所处的干燥阶段不同.当单位质量干燥功率在0.2 W/g以下,温度小于55℃,干燥玉米品质较好.在相同的微波干燥功率条件下,随着水分含量的增加,干燥时间延长,颗粒度指数降低,应力裂纹呈增多趋势.

Microwave drying test system was used to study the microwave drying characteristics of maize with different moisture contents as well as the influence on maize processing quality under different heating powers for different heating time. Result shows that the maize microwave drying process can be divided into three sta- ges： pre-drying stage, the constant rate drying stage and the failing rate drying stage; the microwave drying is mainly at constant rate drying stage; and the microwave drying stage varies with the initial moisture content. When the drying power per unit mass was below 0. 2 W/g and the temperature was less than 55℃, the dried maize had better quality. Under the condition of the same microwave drying power, the particle size index de- creased and the stress cracks increased with increase of the moisture content and the drying time.