无线电波频率和温度变化对狭鳕鱼糜介电特性的影响

Effect of Radio Frequency and Temperature on the Dielectric Properties of Pollock Surimi

为获得狭鳕鱼糜低温低频加热下的介电特性,采用同轴探针方法测定-18~18℃,频率2.1~1000 MHz内狭鳕鱼糜的介电常数和介电损失。结果表明,狭鳕鱼糜的介电常数随着频率增大而减小,随着温度升高呈先增大后减小趋势;当温度一定时,狭鳕鱼糜的介电损失随着频率增大而减小。当加热频率为27.1 MHz时,狭鳕鱼糜的介电损失值大于915 MHz时的介电损失,27.1 MHz的穿透深度远高于915 MHz频率下的穿透深度。微波具有穿透深度小的局限性,无线电波较微波更适合解冻大型物料。本研究结果为应用无线电波解冻狭鳕鱼糜提供了有效的技术手段和参考依据。

To obtain the dielectric properties of the Pollock surimi in the process of heat at low temperature and low frequency,the dielectric constant and loss factor of Pollock surimi were determined by the open ended coaxial-line probe method at the frequency range from 2. 1 to 1000 MHz and temperature from-18℃ to 18℃. The results showed that the dielectric constant of Pollock surimi decreased with an increase of the frequency. The dielectric constant changed quadrially while with a temperature increase： first increased and then decreased. The loss factor decreased with the increase of frequency. The loss factor of frequency at 27. 1 MHz was much higher than that at 915 MHz. The penetration depth of frequency at 27. 1 MHz was much higher than that at 915 MHz. Thus,microwave has the limitation of low penetration. Radio frequency is more suitable than microwave to temper large materials. This research provides an effective technical method for the application of radio frequency for tempering of Pollock surimi.