微波干燥工艺参数对玉米爆腰率的影响

玉米收获后需干燥至安全水分后储藏，干燥方式及合理的工艺过程对干燥品质有很大的影响，玉米干燥后的爆腰率是其品质的重要指标。利用自制的微波干燥试验测试系统对玉米进行干燥试验，得出了玉米微波干燥的特征曲线及干燥温度特性，探讨了三个主要工艺参数单位功率、干燥最高温度、平均失水率对爆腰率的影响。实验结果表明，玉米微波干燥中按失水率的变化可以分为预热、恒速、降速三个阶段，预热段较长，水分主要在恒速段排出；温度经历了上升和趋于稳定的过程；爆腰率随各参数的增大而升高。得到的初步结论是：玉米微波干燥最好在单位干燥功率0.3W／g以下、干燥最高温度不超过70℃、平均失水率不大于0.2％／min的条件下进行。

Effect of Technology Parameter of Microwave Drying on Breakdown Rate of Maize

The maize harvested would be stored after it dried to the safe moisture. The drying method and the reasonable technology process had a very tremendous impact on the quality of maize, and the breakdown rate of dried maize is an important index for maize quality. In this paper, the maize was dried with home-made microwave drying and testing device in order to gained the influence of the feature curve of microwave drying of maize,the temperature characteristics of microwave drying of maize and three main process parameters such as power units, the highest drying temperature, dehydrating rate on the breakdown rate. The experimental results showed that according to the change of the dehydrating rate, the microwave drying was divided to three periods： preheating period, constant drying rate period and falling drying rate period. The preheating period was longer than others, and the moisture content mainly discharged in the constant drying rate period. During this microwave drying process the temperature experienced two rising processes and a stabilizing process; and the breakdown rate was rising with every parameter＇s raising. Synthesized all factors the optimal conditions of microwave drying of maize can be obtained： the best unit drying power was under 0.3w/g, and the maximum drying temperature didn＇t surpass 70℃, and the average water rate wasn＇t bigger than 0.2%. The microwave drying of maize had better reference value to the determination of the dry parameter in practice.