Effect of lactose content on dielectric properties of whole milk and skim milk

Abstract

Summary 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.

Production of Probiotic Passion Fruit (Passiflora edulis Sims f. flavicarpa Deg.) Drink Using Lactobacillus reuteri and Microencapsulation via Spray Drying

“…The reducing sugar content found on passion fruit pulp was 4.86%. This value is similar to the concentration of lactose content found on whole bovine milk, which is frequently used to ferment and growth of Lactobacillus reuteri culture [23]. Is important reinforce that reducing sugar present on passion fruit pulp is different from reducing sugar found in milk.…”

Biochemical, dielectric and surface characteristics of freeze-dried bovine colostrum whey powder

“…Dairy products exhibit different functional and physical properties, in which dielectric properties (DPs) is one of the main physical parameters. This property assists in predicting the heating rates of the material when exposed or subjected to high frequency in dielectric heating like a microwave ( Liu, Guo, & Zhu, 2018 ). The dielectric property (DP) as a function of temperature and frequency of dairy products including milk or whey-based powders was extensively studied by different researchers across the world ( Dag et al, 2019 , Liu et al, 2018 ).…”

“…This property assists in predicting the heating rates of the material when exposed or subjected to high frequency in dielectric heating like a microwave ( Liu, Guo, & Zhu, 2018 ). The dielectric property (DP) as a function of temperature and frequency of dairy products including milk or whey-based powders was extensively studied by different researchers across the world ( Dag et al, 2019 , Liu et al, 2018 ). Besides this, another characterization technique is Fourier transform infrared spectroscopy (FTIR) which is widely performed for the estimation of functional groups in food samples ( Ostrowska-Ligęza, Górska, Wirkowska, & Koczoń, 2012 ).…”

Quantitatively determining the somatic cell count of raw milk using dielectric spectra and support vector regression

“…Therefore, the electric conductivity of milk has been used to detect the mastitis grades of dairy cows (Khatun et al, 2017), but the high false-positive rate makes it difficult for providing reliable results and cannot be used to quantitatively predict SCC. Several studies have shown that the dielectric properties of milk are closely related to its fat (Zhu et al, 2015b), protein (Zhu et al, 2015a), lactose (Liu et al, 2018), and salt (Zhu et al, 2018a) contents. Therefore, the dielectric spectra over a wide frequency range might provide more information related to SCC than the electric conductivity, and the dielectric spectra would be able to quantitatively detect the SCC of milk, but the potential has not been investigated.…”