Department of Agro-Food Science, Niigata Agro-Food University, Niigata, Japan.
Department of Food Engineering, Ankara University, Ankara, Turkey.
Crit Rev Food Sci Nutr. 2022;62(3):598-618. doi: 10.1080/10408398.2020.1823815. Epub 2020 Sep 22.
During radio frequency (RF) thawing-tempering (defrosting) of frozen food products, some regions, mostly along the corners and edges, heat-thaw first due to the strong interaction of electric field and evolved heating leading to temperature increase. Resulting higher power absorption along these regions, compared to the rest of the volume, is the major cause of this problem. Besides, increase in temperature with phase change results in a significant increase of dielectric properties. This situation leads to runaway heating, which triggers the non-uniform temperature distribution in an accelerated manner. All these power absorption and temperature non-uniformity-based changes lead to significant quality changes, drip losses, and microbial growth. Based on this background, the objective of this review was to provide a comprehensive background regarding the most relevant and novel defrosting application studies using RF process, dielectric property data for frozen foods in the RF band, and novel mathematical modeling based computer simulation approaches to achieve a uniform process. Experimental and modeling studies were related with electrode position, sample geometry and size, electrode gap of the applied RF process, and the potential of charged electrode. Applying translational and rotational movement of the food product and the charged electrode vertical movement during the process to adjust the electric field and use of two-cavity systems and curved electrodes were also explained in detail. The data presented in this review is expected to give an insight information for further development of innovative RF thawing/tempering systems.
在射频（RF）解冻-回火（解冻）冷冻食品的过程中，由于电场的强烈相互作用和产生的加热导致温度升高，一些区域（主要是角落和边缘）首先加热解冻。与体积的其余部分相比，这些区域的功率吸收增加是造成这种问题的主要原因。此外，随着相变温度的升高，介电性能会显著增加。这种情况会导致失控加热，从而以加速的方式引发非均匀温度分布。所有这些基于功率吸收和温度不均匀性的变化都会导致显著的质量变化、滴水损失和微生物生长。基于这一背景，本综述的目的是提供一个全面的背景，涉及使用 RF 工艺的最相关和最新的解冻应用研究、RF 波段冷冻食品的介电特性数据，以及基于计算机模拟的新型数学建模方法，以实现均匀的过程。实验和建模研究与电极位置、样品几何形状和尺寸、应用 RF 工艺的电极间隙以及带电电极的潜力有关。在过程中平移和旋转食品产品以及带电电极的垂直运动，以调整电场并使用双腔系统和弯曲电极，也进行了详细解释。本综述中提供的数据有望为创新型 RF 解冻/回火系统的进一步发展提供深入的信息。
