胡萝卜在不同功率模式下的微波真空干燥

Microwave-Vacuum Drying of Carrot under Various Power Modes

试验采用微波真空干燥方法,在连续、间歇、连续与间歇组合的3种微波功率输出模式下,对胡萝卜丁进行干燥试验。分别采用不同压力(5.1kPa、11.9kPa、18.3kPa)、不同功率密度(1.0W/g、1.5W/g、2.0W/g)、同一开断周期(120s)的不同微波开断时间(90s-on/30s-off、60s-on/60s-off、30s-on/90s-off)对产品温度和干燥速率的影响进行研究。在此基础上,提出了在2.0W/g、5.1kPa条件下,1h连续与2h间歇(90s-on/30s-off)的组合模式,并比较了3种模式下的产品温度、干燥速率和能量利用率。试验结果显示,压力、微波功率密度、微波开断时间之比均对产品温度和干燥速率有影响,其中功率密度是最主要的影响因素。在3种模式中,1h连续与2h间歇的组合模式产品温度较低,能量利用率较高。

Microwave-vacuum drying experiment of carrot cube was implemented in the following three Microwave power output modes including continuous mode, intermittent mode and the combination of continuous and intermittent. The present i 11.9kPa; 18.3kPa） microwave nvestlgat power d ion purposes were to study the effects of diverse absolute pressures （5.1kPa; ensities （1.OW/g; 1.5W/g; 2.0W/g） along with different power-on and -off interval （90s-on/30s-off, 60s-on/6Os-off, and 30s-on/90-of0, on product temperature and drying rate. Furthermore, the combination made of 1 h continuous microwave followed by 2 h intermittent microwave treatment with 90s-on/30s-off operating, under the condition of constant power density （2.0W/g） and absolute pressure （5. lkPa）, was presented. The experiment, to compare the product temperature, drying rate and energy utilization under three power modes, was conducted. The results showed that absolute pressure, power density and power-on/power-off time can influence the product temperature and drying rate, among which power density is the key factor. The combination application of microwave continuous mode and intermittent mode not only brings about the higher drying rate, but also offers product temperature, increases energy utilization.