Abstract The evolution of dielectric properties of starch-based food pellets with different moisture contents was measured during microwave expansion to determine the effect of water content on the expansion dynamics. Dynamic dielectric measurements were found to be an excellent procedure to in situ monitor and characterize the different stages in the material transformation of food pellets during microwave expansion. Although the maximum bulk expansion of pellets was achieved at a moisture content of approximately 8% (wet basis), comparative analysis showed that a moisture content 10–11% produced the best results considering the tradeoff between the foaming and expansion temperature. This was due to the high expansion index and an expansion temperature that was sufficiently lower than the onset temperature for pellet scorching, which provides an operating window to maximize expansion and minimize the likelihood of burning. Dielectric measurements during microwave heating in short on/off cycles prior to pellet expansion suggested that the water was not as dielectrically bound for high moisture content pellets.

中文翻译：

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“含水量对微波膨胀过程中食品零食颗粒介电特性动态测量的影响”

摘要 测量了不同水分含量的淀粉基食品颗粒在微波膨胀过程中介电特性的变化，以确定水分含量对膨胀动力学的影响。动态介电测量被发现是一种很好的方法，可以在微波膨胀过程中原位监测和表征食物颗粒材料转变的不同阶段。虽然颗粒的最大体积膨胀是在含水量约为 8%（湿基）时实现的，但比较分析表明，考虑到发泡和膨胀温度之间的权衡，10-11% 的含水量产生了最好的结果。这是由于高膨胀指数和充分低于颗粒焦化开始温度的膨胀温度，它提供了一个操作窗口，以最大限度地扩大膨胀并最大限度地减少燃烧的可能性。在粒料膨胀之前的短开/关循环中进行微波加热期间的介电测量表明，对于高水分含量的粒料，水的介电结合程度较低。