This work is intended to develop an overall understanding of puffing of a starch‐based snack in a home microwave oven, using primarily the microwave energy. Combination of experimental measurements was used, including dynamic mechanical thermal analysis, CT‐Scan, SEM, image processing, and measurement of temperature, moisture content, and expansion ratio. Effects of various product and process parameters on puffing, including those of pretreatment to produce the half product, were studied. Experimental data showed that the physicochemical processes contributing to crust formation were gelatinization of starch, migration of soluble ingredients to the surface, and shrinkage at the surface. A thicker material was harder to puff due to its increased mechanical resistance. Higher microwave power, leading to higher rate of evaporation, increased expansion. Evolution of mechanical properties of the crust greatly affected the final shape of the puffed product. In overall understanding, critical determinants of a puffing process were attributed to three material factors (reduced surface permeability, optimal moisture content, and deformability) and two process factors (intense heat and higher internal pressure from evaporation).

中文翻译：

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了解家用微波炉中的膨化

这项工作旨在主要利用微波能量来发展对家用微波炉中淀粉类零食膨化的总体理解。结合使用了各种实验测量方法，包括动态机械热分析，CT-Scan，SEM，图像处理以及温度，水分含量和膨胀率的测量。研究了各种产品和工艺参数对膨化的影响，包括预处理以生产半成品的效果。实验数据表明，导致硬皮形成的物理化学过程是淀粉的糊化，可溶性成分向表面的迁移以及表面的收缩。较厚的材料由于其增加的机械阻力而难以吹胀。更高的微波功率，导致更高的蒸发速率，增加扩展。地壳机械性能的演变极大地影响了膨化产品的最终形状。从总体上看，膨化过程的关键决定因素归因于三个物质因素（降低的表面渗透性，最佳水分含量和可变形性）和两个过程因素（强烈的热量和更高的蒸发内部压力）。