Abstract The microwave radiation thermal treatment of rice flour was studied and its impact on physical and structural characteristic in relation to the initial moisture content (IMC) (20% and 30%) was evaluated. To explain the fundamentals of observed changes the microwave radiation absorption capacity of flour as well as temperature and moisture change during the treatment were evaluated. The flour particle morphological structure as well as crystallinity/amorphous region ratio changed after the treatment. The flour thermal properties also altered revealing IMC significant impact on the gelatinization temperature, that raised up to 3 °C, and the amylopectin retrogradation extent that increased up to a 7% in the most intense microwave-treated flours with respect to the native flour. Lower peak, setback and breakdown viscosities - that decreased with respect to the native flour up to 42%, 34% and 86% respectively-and higher pasting temperatures -that increased up to 10 oC- were also observed. An exceptional microwave irradiation efficiency resulting in rice flour physical changes in significantly shorter times, 4–8 min, than conventional heat-moisture treatment processes was concluded.

中文翻译：

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米粉的微波吸收能力。辐射对米粉微观结构、热和粘度特性的影响

摘要 研究了微波辐射热处理米粉，并评估了其对初始含水量（IMC）（20%和30%）物理和结构特性的影响。为了解释观察到的变化的基本原理，评估了面粉的微波辐射吸收能力以及处理过程中的温度和湿度变化。处理后面粉颗粒的形态结构以及结晶度/非晶区比发生了变化。面粉的热特性也发生了变化，表明 IMC 对糊化温度有显着影响，最高可达 3°C，支链淀粉回生程度在最强烈的微波处理面粉中比天然面粉增加了 7%。较低的峰值，还观察到挫折和分解粘度——相对于原生面粉分别降低了 42%、34% 和 86%——以及更高的糊化温度——增加了 10 oC——。得出的结论是，与传统的湿热处理工艺相比，卓越的微波辐射效率在 4-8 分钟内显着缩短了米粉的物理变化。