Effect of lactose content on dielectric properties of whole milk and skim milk |
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| Authors: | Qiang Liu Wenchuan Guo Xinhua Zhu |
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| Affiliation: | College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi, China |
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| Abstract: | Dielectric properties (dielectric constant ε′ and dielectric loss factor ε′′) of whole milk and skim milk with the lactose content of 4.56–6.44% and 4.57–6.47%, respectively, were measured over the frequency range of 20–4500 MHz at 25 °C using a vector network analyzer. The results showed that ε′ decreased with increasing frequency, and ε′′ changed with V shape and its minimum was noted at about 2000 MHz. Whole milk had lower dielectric properties than skim milk at almost same lactose content and a given frequency. ε′ had weak positive linear relationship with lactose content for whole milk, but had negative linear relationship for skim milk. No matter for which milk, ε′′ had very good negative linear relationship with lactose content below 1000 MHz and had good positive linear relationship above 2300 MHz. The study provides information on developing rapid lactose detector for milk in future. |
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| Keywords: | Correlation dielectric constant dielectric loss factor lactose content microwave milk permittivities radio frequency |
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