title: Identification of Acyl Chain Oxidation Products upon Thermal Treatment of a Mixture of Phytosteryl/-stanyl Linoleates.
abstract: A mixture of phytosterols/-stanols, consisting of 75% β-sitosterol, 12% sitostanol, 10% campesterol, 2% campestanol, and 1% others, was esterified with linoleic acid. The resulting mixture of phytosteryl/-stanyl linoleates was subjected to thermal oxidation at 180 °C for 40 min. A silica solid-phase extraction was applied to separate a fraction containing the nonoxidized linoleates and nonpolar degradation products (heptanoates, octanoates) from polar oxidation products (oxo- and hydroxyalkanoates). In total, 15 sitosteryl, sitostanyl, and campesteryl esters, resulting from oxidation of the acyl chain, could be identified by GC-FID/MS. Synthetic routes were described for authentic reference compounds of phytosteryl/-stanyl 7-hydroxyheptanoates, 8-hydroxyoctanoates, 7-oxoheptanoates, 8-oxooctanoates, and 9-oxononanoates, which were characterized by GC-MS and two-dimensional NMR spectroscopy. The study provides data on the formation and identities of previously unreported classes of acyl chain oxidation products upon thermal treatment of phytosteryl/-stanyl fatty acid esters.
authors.affiliation: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wocheslander
authors.affiliation: Lehrstuhl für Biochemie, Technische Universität München , Lichtenbergstrasse 4, D-85748 Garching, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.affiliation: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Scholz
authors.affiliation: Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit , Veterinärstrasse 2, D-85764 Oberschleissheim, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Lander
authors.affiliation: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising, Germany.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Engel
mesh_terms: D002784:Cholesterol / Q000031:analogs & derivatives / Q000737:chemistry; D004952:Esters / Q000737:chemistry; D006358:Hot Temperature; D008041:Linoleic Acids / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010840:Phytosterols / Q000737:chemistry*; D012855:Sitosterols / Q000737:chemistry
chemical_list: D004952:Esters; D008041:Linoleic Acids; D010840:Phytosterols; D012855:Sitosterols; C003535:campestanol; C021273:campesterol; C025473:gamma-sitosterol; D002784:Cholesterol; C021255:stigmastanol
keywords: NMR spectroscopy; core aldehydes; fatty acid cleavage; phytosteryl ester oxidation; solid-phase extraction