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Dobson, Gary; Christie, William W.; Sébédio, J. L.

doi:10.3989/gya.1996.v47.i1-2.839

Cited by 12 publications

(2 citation statements)

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“…3 suggests that, in addition to an oxidation process, other oil transformations occurring during heating, may contribute to the decrease in the number of oil double bonds. In this context, the formation of small amounts of complex mixtures of monocyclic fatty acids in heattreated vegetable oils, at temperatures between 140 and 200 ºC, leading in turn to a decrease in the unsaturation degree value of the oil, has been previously reported (Dobson, Christi, & Sebedio, 1996). A much larger fall in the unsaturation level of ABO oil was obtained by increasing the temperature to 225 ºC.…”

Section: Structural Analysismentioning

confidence: 74%

A study of the evolution of the physicochemical and structural characteristics of olive and sunflower oils after heating at frying temperatures

Fernández

Garcı́a

2006

Food Chemistry

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Section: Structural Analysismentioning

confidence: 74%

A study of the evolution of the physicochemical and structural characteristics of olive and sunflower oils after heating at frying temperatures

Fernández

Garcı́a

2006

Food Chemistry

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“…[5,12] The origin of CFAM is made possible by unsaturated fatty acids transformation, particularly oleic, linoleic, and linolenic acids. [10,[12][13][14] Oleic acid, although its presence in a high proportion in vegetable oils, is the least exposed to the intramolecular cyclization process. The result of oleic acid cyclization is the formation of eight saturated isomers (four cycles of cyclopentyl type and four cycles of cyclohexyl type).…”

Section: Introductionmentioning

confidence: 99%

GC‐MS Characterization of Cyclic Fatty Acid Monomers and Isomers of Unsaturated Fatty Acids Formed During the Soybean Oil Heating Process

Chérif

Boukhchina

Angers

2019

Euro J Lipid Sci & Tech

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In this work, the possibility of formation and isolation of cyclic fatty acid monomers (CFAM) from polyunsaturated fatty acids via prolonged heat treatment of soybean oil are studied. The structures of CFAM are determined using Gas chromatography‐Mass spectrometry (GC‐MS) of their 4, 4‐dimethyloxazoline (DMOX) derivatives, the yield of derivatization is 98%. Among CFAM, the cyclohexyl fatty acids with ring from C12 to C17 and the cyclohexneyl with ring from C10 to C15 formed acid are detected by GC‐MS. The new cyclopentyl with ring at C14 position or between C13 to C17 are detected from linoleic acid. Also, the variation of major fatty acids composition of soybean oil during heated treatment at 150, 180, 210, and 240 °C for 60 h are analyzed. The results indicate that after heating, soybean oil contains four isomers of conjugated linoleic acid (CLA), four isomers of C18:1 and four isomers of C18:3. The heating process, the enrichment steps, and CFAM concentration can modify the profile of CFAM and permit the emergence of new compounds, which can be useful to know the edible oil structural changes during the phases of extraction and analysis. Practical Applications: When heated at high temperature for a long time, soybean oil undergoes isomerization and cyclization reactions. In fact, CFAM structures with five and six membered carbon rings are identified from heated oil. A new mass spectrum of the CFAM derivative from the intramolecular C18:2 cyclization is also described. Although CFAM are present at very low concentrations in heated oils, these compounds are the most toxic metabolites produced in soybean oil heated at high temperature. In addition to the four isomers of conjugated linoleic acid, four isomers of C18:1 and four of C18:3 are detected during the heating process. The data clearly show that it is necessary to avoid heating the soybean oil to a temperature above 210 °C for a period of more than 60 h which can minimize the production of CFAM. The gap of 68 amu between the molecular ion (333) and m/z 265 indicate the location of cyclopentyl ring at C14, which is first determined in heated soybean oil.

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Physical refining of edible oils

Čmolík¹,

Pokorný

2000

Eur. J. Lipid Sci. Technol.

129

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Crude oils obtained by oilseed processing have to be refined before the consumption in order to remove undesirable accompanying substances. The traditional alkali refining is often replaced by physical refining in which the use of chemicals is reduced. The most widely used method is steam refining. The crude oil quality is very important in order to obtain high quality refined oil. Furthermore, the oil should be efficiently degummed to remove phospholipids as well as heavy metals and bleached to remove pigments. The most important step consists of the application of superheated steam under low pressure and at temperatures higher than 220°C. Both free fatty acids and objectionable volatiles, formed by cleavage of lipid oxidation products, are removed. A disadvantage is the partial loss of tocopherols. Side reactions, particularly isomerization of polyunsaturated fatty acids, should be minimized. The quality of physically refined oil is close to that of alkali refined oils, but losses of neutral oil are lower and the environment is less polluted. Among other methods of physical refining the application of selective membranes is promising.

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Cited by 12 publications

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A study of the evolution of the physicochemical and structural characteristics of olive and sunflower oils after heating at frying temperatures

A study of the evolution of the physicochemical and structural characteristics of olive and sunflower oils after heating at frying temperatures

GC‐MS Characterization of Cyclic Fatty Acid Monomers and Isomers of Unsaturated Fatty Acids Formed During the Soybean Oil Heating Process

Physical refining of edible oils

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