Abstract Due to the inherent nature of standing wave patterns of microwaves inside a domestic microwave oven cavity and varying dielectric properties of different food components, microwave heating produces non-uniform distribution of energy inside the food. Non-uniform heating is a major food safety concern in not-ready-to-eat (NRTE) microwaveable foods. In this study, we present a method for assessing heating rate and non-uniform heating in domestic microwave ovens. In this study a custom designed container was used to assess heating rate and non-uniform heating of a range of microwave ovens using a hedgehog of 30 T-type thermocouples. The mean and standard deviation of heating rate along the radial distance and sector of the container were measured and analyzed. The effect of the location of rings and sectors was analyzed using ANOVA to identify the best location for placing food on the turntable. The study suggested that the best location to place food in a microwave oven is not at the center but near the edge of the turntable assuming uniform heating is desired. The effect of rated power and cavity size on heating rate and non-uniform heating was also studied for a range of microwave ovens. As the rated power and cavity size increases, heating rate increases while non-uniform heating decreases. Sectors in the container also influenced heating rate (p < 0.0001), even though it did not have clear trend on heating rate. In general, sectors close to the magnetron tend to heat slightly faster than sectors away from the magnetron. However, the variation in heating rate among sectors was only 2 °C/min and considered not practically important. Overall heating performance such as mean heating rate and non-uniform heating did not significantly vary between the two replications that were performed 4 h apart. However, microwave ovens were inconsistent in producing the same heating patterns between the two replications that were performed 4 h apart.

中文翻译：

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家用微波炉加热速度和加热不均匀的评估

摘要 由于家用微波炉腔内微波驻波模式的固有特性以及不同食物成分的不同介电特性，微波加热会导致食物内部能量分布不均匀。非均匀加热是非即食 (NRTE) 可微波食品的主要食品安全问题。在这项研究中，我们提出了一种评估家用微波炉加热速度和不均匀加热的方法。在这项研究中，定制设计的容器用于评估使用 30 T 型热电偶刺猬的一系列微波炉的加热速率和非均匀加热。测量和分析沿容器径向距离和扇区的加热速率的平均值和标准偏差。使用方差分析来分析环和扇区位置的影响，以确定将食物放在转盘上的最佳位置。该研究表明，假设需要均匀加热，将食物放入微波炉的最佳位置不是在中心，而是靠近转盘的边缘。还研究了一系列微波炉的额定功率和腔尺寸对加热速率和非均匀加热的影响。随着额定功率和腔体尺寸的增加，加热速率增加，而不均匀加热减少。容器中的扇区也影响加热速率（p < 0.0001），即使它没有明显的加热速率趋势。一般而言，靠近磁控管的扇区往往比远离磁控管的扇区加热得稍微快一些。然而，各部门之间的加热速率变化仅为 2°C/min，被认为实际上并不重要。整体加热性能，例如平均加热速率和非均匀加热，在相隔 4 小时进行的两次复制之间没有显着差异。然而，微波炉在相隔 4 小时的两次复制之间产生相同的加热模式时不一致。