Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat
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 o...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-09-01
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| Series: | Foods |
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| Online Access: | https://www.mdpi.com/2304-8158/9/9/1273 |
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| author | Berthold Wiege Eberhard Fehling Bertrand Matthäus Marcus Schmidt |
| author_facet | Berthold Wiege Eberhard Fehling Bertrand Matthäus Marcus Schmidt |
| author_sort | Berthold Wiege |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T16:24:35Z |
| format | Article |
| id | doaj.art-9773d00cddac4235a7eca72238b68de8 |
| institution | Directory Open Access Journal |
| issn | 2304-8158 |
| language | English |
| last_indexed | 2024-03-10T16:24:35Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Foods |
| spelling | doaj.art-9773d00cddac4235a7eca72238b68de82023-11-20T13:20:21ZengMDPI AGFoods2304-81582020-09-0199127310.3390/foods9091273Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm FatBerthold Wiege0Eberhard Fehling1Bertrand Matthäus2Marcus Schmidt3Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Cereals, 32756 Detmold, GermanyMax Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Cereals, 32756 Detmold, GermanyMax Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Cereals, 32756 Detmold, GermanyMax Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Cereals, 32756 Detmold, GermanyDeep-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.https://www.mdpi.com/2304-8158/9/9/1273deep-fat fryingsunflower oilpalm fatdielectric constantviscosity |
| spellingShingle | Berthold Wiege Eberhard Fehling Bertrand Matthäus Marcus Schmidt Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat Foods deep-fat frying sunflower oil palm fat dielectric constant viscosity |
| title | Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat |
| title_full | Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat |
| title_fullStr | Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat |
| title_full_unstemmed | Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat |
| title_short | Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat |
| title_sort | changes in physical and chemical properties of thermally and oxidatively degraded sunflower oil and palm fat |
| topic | deep-fat frying sunflower oil palm fat dielectric constant viscosity |
| url | https://www.mdpi.com/2304-8158/9/9/1273 |
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