Dielectric properties for monitoring the quality of heated oils

El-Shami, S. M.; Selim, I. Z.; El-Anwar, I. M.; El-Mallah, M. Hassan

doi:10.1007/bf02636335

Cited by 43 publications

(20 citation statements)

References 6 publications

(6 reference statements)

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“…11. The dielectric constant of a vegetable oil blend of cottonseed and sunflower oil was reported to have increased by as much as 0.5 during the accelerated oxidation process [21]. It should be noted, however, that the impact of a change in the dielectric constant on the accuracy decreases for a decreasing film thickness.…”

Section: Resultsmentioning

confidence: 97%

The Study of the Dynamic Thickness of Organic Boundary Films Under Metallic Sliding Contact

Chua

Stachowiak

2010

Tribol Lett

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The paper herein proposes a method to simultaneously measure the friction, wear, and thickness of boundary films under a pure sliding contact between metallic surfaces. The method is based on the capacitance method used by Crook and Dyson et al. to measure elastohydrodynamic film thicknesses. Pilot tests conducted on sunflower oil using the new method showed an appreciable growth in the boundary film thickness, with a corresponding drop in the coefficient of friction. Very little wear was observed during the film growth. It is postulated that this growth was due to the polymerization of the unsaturated fatty acid chains.

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Section: Resultsmentioning

confidence: 97%

The Study of the Dynamic Thickness of Organic Boundary Films Under Metallic Sliding Contact

Chua

Stachowiak

2010

Tribol Lett

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“…Simple and rapid methods for the detection of thermal abuse of oil are need of the hour. Many research works were carried out on dielectric properties of frying fats and oils (EI-Shaml et al 1992;Paul and Mittal 1996;Inoue et al 2002;Cataldo et al 2010). They reported that the dielectric constant is the most significant indicator for monitoring frying oil quality (quality control) in commercial deep fat frying operations.…”

Section: Food Grainsmentioning

confidence: 99%

Measurement techniques and application of electrical properties for nondestructive quality evaluation of foods—a review

et al. 2011

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Non-destructive systems are recent trends for quality evaluation of fruits and vegetables. Information on post-harvest variations in electrical properties is needed to develop new instruments for this purpose. Electrical properties are finding increasing application in agriculture and food processing industries. Knowledge of dielectric properties of foods as a function of moisture content and temperature is essential in the design and control of drying systems. As simple, rapid and non-destructive measuring techniques, dielectric spectroscopy provides information about the dielectric response of materials to electromagnetic field. Electrical properties of agricultural materials have been of interest for many years. The interest in dielectric properties of materials has historically been associated with the design of electrical equipment. This review paper covers theoretical aspects of different electrical properties, their measurement techniques, applications of dielectric properties in agriculture/food processing sector and potential applications of thermal imaging (TI) for quality and safety assessment in food processing. The values of dielectric properties of a number of products including food grains, fruits and vegetables, and meat and meat products are presented in table form. This comprehensive coverage will be useful for academic, scientific and industrial community in treating and applying the facts in developing/testing new processes and products based on electromagnetic energy application.Keywords Electrical properties . Non-destructive . Measuring techniques . Dielectric constant . Loss factor . Thermal imaging technique . Food quality evaluationThe material investigation and moisture measurement using electromagnetic waves in wide spectrum serve for quality control and improvement in many branches like industry, forest and wood-working industry, civil engineering, agriculture, commerce and also foods e.g. for quality evaluation of meat, fruits, coffee etc (Hlavacova 2003; Venkatesh and Raghavan 2004). Non-destructive evaluation of quality based on constituents of fruits and vegetables has been successfully used (Chen et al. 1999;Jha et al. 2001;Kawano 1998). Electrical characteristics of agricultural materials have been of interest for many years (Nelson 2006) and are utilized in many areas of human activities. Techniques for non-destructive determination of quality and related characteristics of agricultural products are helpful to producers, handlers and processors . Permittivity and moisture can be closely correlated when water content is high. Knowledge of dielectric properties in partially frozen material is critical in determining the rates and uniformity of heating in microwave thawing. Electrical properties are important in processing foods with pulsed electric fields, ohmic heating, induction heating, radio frequency, and microwave heating. These properties are also useful in the detection of processing conditions or the quality of foods (Barbosa-Canovas et al. 2006). Considering ...

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“…Relation between TPC values and viscosity for oil was studied by early researchers and was observed that they were linearly correlated (Al-Kahtani 1991;El-Shami et al 1992). The maximum suggested levels for polar compounds present in frying or cooking fats and oil is 25/100 g of oil or 25 % (Pace et al 1968;Risman and Bengtsson 1971;El-Shami et al 1992).…”

Section: Introductionmentioning

confidence: 99%

“…The maximum suggested levels for polar compounds present in frying or cooking fats and oil is 25/100 g of oil or 25 % (Pace et al 1968;Risman and Bengtsson 1971;El-Shami et al 1992). Dillip Kumar et al (2013) have suggested that electrical properties may be used as indicators of condition and quality of edible oil.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of electro-rheological properties of modeled vegetable oils

et al. 2015

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Vegetable oil becomes polarized on oxidation and polymerization resulting in the formation of peroxide, triglycerides, etc. The quality and reusable state were investigated for sunflower, sesame, rice bran oil and model oil with the addition of oleic acid (2, 4 and 6 %) and antioxidants (citric and tert-Butyl hydroquinone-TBHQ). Excessive reclaims of cooking oil produce toxic by-products due to chemical breakdown that induce the production of polar compounds in oil. To determine the consumable fitness, variations of dielectric constant are observed at different temperatures (29 to 70°C) and frequencies (1 to 10 7 Hz) for the cooking oil. Physical parameters, such as viscosity and density associated with the saturated and unsaturated fatty acid, are also measured at different temperatures to determine the quality of oil. Dielectric constant and viscosity are correlated and analyzed using a newly developed equation with high correlation constant (R 2 =0.998) for oil added with citric acid. Oil added with 2-4 % of oleic acid is observed to have high determination coefficient (R 2 > 0.92). A lowest correlation (R 2 =0.6-0.7) was observed for the oil added with TBHQ. The present study also states that addition of TBHQ to oil does not impede oxidation reaction. Besides, even the shelf life of the oil could not be enhanced and may produce adverse effects in human health.

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Dielectric properties for monitoring the quality of heated oils

Cited by 43 publications

References 6 publications

The Study of the Dynamic Thickness of Organic Boundary Films Under Metallic Sliding Contact

The Study of the Dynamic Thickness of Organic Boundary Films Under Metallic Sliding Contact

Measurement techniques and application of electrical properties for nondestructive quality evaluation of foods—a review

Experimental investigation of electro-rheological properties of modeled vegetable oils

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