College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, China.
Food Sci Technol Int. 2024 Jan;30(1):3-17. doi: 10.1177/10820132221123437. Epub 2022 Sep 5.
Radio frequency (RF) heating has been studied to inactivate bacteria in some powder foods. In this study, a 6 kW, 27.12 MHz RF system was used to pasteurize in black fungus powder. The effects of different conditions (initial a, electrodes gaps, particle sizes) on RF heating rate and uniformity were investigated. The results showed that RF heating rate was significantly ( < 0.05) improved with decreasing electrodes gap and increasing initial a, and the heating rate was the slowest when the particle size was 120-160 mesh. However, these factors had no significant ( > 0.05) influence on heating uniformity. RF pasteurization of in black fungus powder was also studied. The results showed that, to inactivate for 5 log reductions in the cold spot (the center of surface layer), the time needed and bacteria heat resistance at designated temperature (65, 75, 85 °C) decreased with increasing a, and the first order kinetics and Weibull model could be used to fit inactivation curves of with well goodness. Quality analysis results showed that although RF pasteurization had no significant ( > 0.05) effect on polysaccharide (AAP) and total polyphenols, obvious changes were found on color. Results suggested that RF pasteurization can be considered as an effective pasteurization method for black fungus powder.
射频（RF）加热已被研究用于灭活某些粉末食品中的细菌。在这项研究中，使用了一个 6kW、27.12MHz 的 RF 系统来对黑木耳粉进行巴氏杀菌。研究了不同条件（初始含水量、电极间隙、粒径）对 RF 加热速率和均匀性的影响。结果表明，随着电极间隙的减小和初始含水量的增加，RF 加热速率显著提高（<0.05），而当粒径为 120-160 目时，加热速率最慢。然而，这些因素对加热均匀性没有显著影响（>0.05）。还研究了 RF 对黑木耳粉的巴氏杀菌。结果表明，为了使冷点（表面层中心）的 减少 5 个对数，所需时间和细菌在指定温度（65、75、85°C）下的耐热性随含水量的增加而降低，一级动力学和 Weibull 模型可用于拟合 失活动力学曲线，拟合度良好。质量分析结果表明，虽然 RF 巴氏杀菌对 多糖（AAP）和总多酚没有显著影响（>0.05），但颜色有明显变化。结果表明，RF 巴氏杀菌可以被认为是一种有效的黑木耳粉巴氏杀菌方法。
