Wheat germ (WG) is a valuable by-product of wheat milling but is highly susceptible to lipid rancidity induced by lipase (LA) activity. Therefore a stabilization step is required to reduce LA activity. Radio-frequency (RF) heating is an alternative thermal technology suitable for processing food and has great potential for WG stabilization. However, in order to develop effective RF stabilization treatments, a knowledge of the dielectric properties (DPs) (i.e. dielectric constant (ε″) and dielectric loss factor (ε″)) of WG at frequencies used for heating is required. Furthermore, an understanding of the influence of RF processing conditions on heating uniformity and LA inactivation is needed. Findings in the present study show that ε′ and ε″of WG increased with increasing temperature and moisture content (MC). Furthermore, the relationship between DPs and temperature/MC can be described by quadratic order models. RF heating uniformity in WG gradually improved with decreasing heating rate from 19.6 to 6.3 °C/min and MC from 15.96 to 7.05% (wet basis, w.b.). Placing the WG on a moving conveyor at 4 m/h slightly improved RF heating uniformity in the interior layers of the WG. Placing a pair of rectangular polyetherimide plates (12 × 8 cm) above and below the container during RF heating at 6.3 °C/min further improved temperature distribution leading to a more uniform LA inactivation in WG. Overall, the results obtained from this study are useful in computer simulation and optimizing process parameters for WG stabilization by RF heating.

小麦胚芽（WG）是小麦碾磨的宝贵副产品，但高度易受脂肪酶（LA）活性诱导的脂质酸败的影响。因此，需要稳定步骤以减少LA活性。射频（RF）加热是一种适用于食品加工的替代热技术，具有稳定工作空间的巨大潜力。然而，为了开发有效的RF稳定化处理，需要了解在用于加热的频率下WG的介电特性（DPs）（即介电常数（ε ″）和介电损耗因子（ε ″））。此外，需要了解RF处理条件对加热均匀性和LA失活的影响。本研究的结果表明ε ′和εWG的”随温度和水分含量（MC）的增加而增加。此外，DPs和温度/ MC之间的关系可以通过二次模型来描述。WG中的RF加热均匀性随着加热速率从19.6到6.3°C / min降低和MC从15.96到7.05％（湿基，wb）逐渐提高。将WG以4 m / h的速度放置在移动的传送带上，可稍微改善WG内层中的RF加热均匀性。在以6.3°C / min的频率进行RF加热期间，在容器的上方和下方放置一对矩形聚醚酰亚胺板（12×8 cm），这进一步改善了温度分布，导致WG中的LA灭活更加均匀。总体而言，从这项研究中获得的结果可用于计算机仿真和优化工艺参数，以通过射频加热来稳定WG。