Dielectric properties of milk during ultra-heat treatment
Dielectric properties of milk during ultra-heat treatment
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DOI：
10.1016/j.jfoodeng.2017.09.025
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发表时间：
2018-02-01
影响因子：
5.5
通讯作者：
Felipe, Xavier
中科院分区：
文献类型：
--
作者：
Munoz, Israel;Gou, Pere;Felipe, Xavier
介电特性对于预测食品的介电加热是很重要的。在10 MHz~2450 MHz的高频范围内，对20℃~150℃的牛乳的介电性能进行了分析。为了评价牛奶的介电杀菌效果，需要研究100℃以上的牛乳的介电常数(epsilon‘和epsilon“)。介电常数(epsilon’)在所有温度下都随频率降低，在低频下随温度升高，在高频下随温度降低。在几乎整个频率范围内，介电损耗因数(epsilon”)随频率而降低，随温度升高而增大。在大多数频率范围内，离子传导是主要的机制。对于灰分含量较高(与盐分含量有关)的牛奶样品，epsilon‘在低频下较高，在高频下较低，而epsilon“在所有频率下都较高。灰分含量较高的牛奶样品的渗透深度较低。(C)2017爱思唯尔有限公司。保留所有权利。
Dielectric properties are important for predicting dielectric heating of foodstuffs. The dielectric properties of three types of milk (raw, skimmed and concentrated non-fat) were analyzed at high frequencies between 10 MHz and 2450 MHz for producing temperatures between 20 degrees C and 150 degrees C. The study of cow milk dielectric constants (epsilon' and epsilon") at conditions above 100 degrees C is needed to evaluate dielectric sterilization of milk. The dielectric constant (epsilon') was found to decrease with frequency at all temperatures but increase with temperature at low frequencies and decrease with temperature at high frequencies. The dielectric loss factor (epsilon") decreased with frequency and increased with temperature in almost the entire range of frequencies. Ionic conduction was the dominant mechanism across most of the frequency range. For milk samples with higher ash content (related to salt content), epsilon' was higher at low frequencies and lower at high frequencies, whereas epsilon" was higher for all frequencies. Penetration depth was lower for milk samples with higher ash content. (C) 2017 Elsevier Ltd. All rights reserved.