Dielectric constant and  induced dipole moment of edible oils  subjected to conventional heating

Gjorgjevich, Margareta Pecovska; Andonovski, A.; Velevska, Julijana

doi:10.20450/mjcce.2012.19

Cited by 22 publications

(12 citation statements)

References 17 publications

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“…Since the density and the atomic and electronic polarizability are nearly independent of temperature, the temperature dependence of ε in Figure 5 can be explained by the temperature dependence of the orientational polarization. In addition, this confirms the results of Pecovska-Gjorgjevich [ 33 ], who demonstrated a decrease in DK with increasing temperature as well. The comparison of the absolute DK values of the two samples also provides evidence for the better heat stability of palm fat compared to that of sunflower oil.…”

Section: Resultssupporting

confidence: 91%

Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat

Wiege

Fehling

Matthäus

et al. 2020

Foods

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Deep-fat frying is an important process used worldwide for the preparation of foods. Due to oxidation, hydrolysis, decomposition and oligomerization, numerous polar compounds are formed. These compounds change the physical, nutritional and sensory properties of the oil or fat. The standard methods of the German Society for Fat Science for the assessment of the quality of frying fats are time consuming and cost intensive. Therefore, alternative cost-effective and sensitive rapid methods, which ideally allow the quantitative determination of the quality of frying fats “in-line” in the deep-frying pan are needed. Sunflower oil and palm fat were thermally and oxidatively degraded in a beaker at atmospheric pressure under intensive stirring for 76 h at 175 °C. To evaluate the development of the physical properties during heat treatment, the viscosity and dielectric constant of these oils were measured. The temperature in a deep-frying pan can vary within a wide range (160–190 °C), and the viscosity and dielectric constant show a strong temperature dependence. Therefore, it was necessary to measure the temperature dependence of the viscosity and dielectric constant of the different degraded oils. Additionally, their chemical properties were characterized by high-performance gel permeation chromatography and Fourier-transform infrared spectroscopy (FTIR). The determination of the dielectric constant, which is directly correlated with the concentration of polar compounds, seems to be the best method for the assessment of the quality of used frying oils.

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Section: Resultssupporting

confidence: 91%

Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat

Wiege

Fehling

Matthäus

et al. 2020

Foods

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“…It is hydrophobic, colorless, and does not change color over time. Mineral oil is non polar and has a very low dielectric constant (ε′ = 2.2) . Pickering emulsions were formed by the ultrasonication of Drakeol-35 and equal volumes of aqueous dispersions of HaP, HaP–PA, Hap–OA, and HaP–SA.…”

Section: Resultsmentioning

confidence: 99%

Dual Stimuli-Responsive Pickering Emulsions from Novel Magnetic Hydroxyapatite Nanoparticles and Their Characterization Using a Microfluidic Platform

et al. 2021

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Stimuli-responsive emulsifiers have emerged as a class of smart agents that can permit regulated stabilization and destabilization of emulsions, which is essential for food, cosmetic, pharmaceutical, and petroleum industries. Here, we report the synthesis of novel “smart” hydroxyapatite (HaP) magnetic nanoparticles and their corresponding stimuli-responsive Pickering emulsions and explore their movement under confined spaces using a microfluidic platform. Pickering emulsions prepared with our magnetic stearic acid-functionalized Fe2O3@HaP nanoparticles exhibited pronounced pH-responsive behavior. We observed that the diameter of emulsion droplets decreases with an increase in pH. Swift demulsification was achieved by lowering the pH, whereas the reformation of emulsions was achieved by increasing the pH; this emulsification-demulsification cycling was successful for at least ten cycles. We used a microfluidic platform to test the stability of the emulsions under flowing conditions and their response to a magnetic field. We observed that the emulsion stability was diminished and droplet coalescence was enhanced by the application of the magnetic field. The smart nanoparticles we developed and their HaP-based emulsions present promising materials for pharmaceutical and petroleum industries, where responsive emulsions with controlled stabilities are required.

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“…The recent methods [9][10] that could be related with electro-optics are dielectric constant. However, this method just only measures due to the increasing polar components in cooking oils after heating or during heating.…”

Section: Resultsmentioning

confidence: 99%

Determination of relative dissociation energy from electro-optics as a new single-proposed parameter of vegetable oil quality

et al. 2019

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In this report, we study the electro-optics effect on cooking oil to obtain the relative dissociation energy as a new single proposed parameter of oil quality. The sample was canola oil which had been heated in 0.5 hours, 2 hours and 4 hours. The light source used in the experiment was a green pointer laser with a wave length of 532 nm. The sample was applied to a potential difference from 0 to 9 kV to obtain the electro-optics effect in form of the change of the polarization angle Dq as function of potential difference DV. The relative dissociation energy was obtained from the fitting data of the relative Lenard-Jones potential energy curves represented by change of polarization per unit change of potential difference, Dq/DV. The result shows that the relative dissociation energy is reduced as the oil quality decreased after heated. The relative dissociation energy provides simple physical understanding about electro-optics effect on cooking oils. The study of electro-optics polarization that represents relative Lenard-Jones potential energy is a new but somewhat intuitive, which can be further improved and emphasized for grouping, mapping, and determining various cooking oil quality and halal food due to the lard contamination.

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Dielectric constant and induced dipole moment of edible oils subjected to conventional heating

Cited by 22 publications

References 17 publications

Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat

Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat

Dual Stimuli-Responsive Pickering Emulsions from Novel Magnetic Hydroxyapatite Nanoparticles and Their Characterization Using a Microfluidic Platform

Determination of relative dissociation energy from electro-optics as a new single-proposed parameter of vegetable oil quality

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