title: Isotope-labeling studies on the formation pathway of acrolein during heat processing of oils.
abstract: Acrolein (2-propenal) is classified as a foodborne toxicant and was shown to be present in significant amounts in heated edible oils. Up to now, its formation was mainly suggested to be from the glycerol part of triacylglycerides, although a clear influence of the unsaturation of the fatty acid moiety was also obvious in previous studies. To unequivocally clarify the role of the glycerol and the fatty acid parts in acrolein formation, two series of labeled triacylglycerides were synthesized: [(13)C(3)]-triacylglycerides of stearic, oleic, linoleic, and linolenic acid and [(13)C(54)]-triacylglycerides with labeled stearic, oleic, and linoleic acid, but with unlabeled glycerol. Heating of each of the seven intermediates singly in silicon oil and measurement of the formed amounts of labeled and unlabeled acrolein clearly proved the fatty acid backbone as the key precursor structure. Enzymatically synthesized pure linoleic acid and linolenic acid hydroperoxides were shown to be the key intermediates in acrolein formation, thus allowing the discussion of a radical-induced reaction pathway leading to the formation of the aldehyde. Surprisingly, although several oils contained high amounts of acrolein after heating, deep-fried foods themselves, such as donuts or French fries, were low in the aldehyde.
authors.affiliation: Deutsche Forschungsanstalt für Lebensmittelchemie and.
authors.forename: Alice
authors.initials: A
authors.lastname: Ewert
authors.forename: Michael
authors.initials: M
authors.lastname: Granvogl
authors.forename: Peter
authors.initials: P
authors.lastname: Schieberle
mesh_terms: D000171:Acrolein / Q000737:chemistry*; D002247:Carbon Isotopes / Q000737:chemistry; D003296:Cooking; D006358:Hot Temperature; D007553:Isotope Labeling; D015394:Molecular Structure; D010938:Plant Oils / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D010938:Plant Oils; D000171:Acrolein
keywords: Acrolein; fatty acid hydroperoxides; foodborne toxicant; frying; labeling studies