title: Non-conjugated cis/trans 18:2 in Beef Fat are Mainly Δ-9 Desaturation Products of trans-18:1 Isomers.
abstract: Human liver cells (HepG2) were cultured with individual trans (t) 18:1 including t6-, t12-, t13-, t14-, t15- and t16-18:1, and retention times of their Δ-9 desaturation products were determined using 100-m biscyanopropyl-polysiloxane and SLB-IL111 columns. Corresponding peaks were found in beef adipose tissues known to have different delta-9 desaturase activities. Further lines of evidence indicating the presence of Δ-9 desaturation products of t-18:1 isomers in beef fat were developed by analysis of fatty acid methyl esters (FAME) fractionated using Ag+-TLC, and by GC/MS. Some of the Δ-9 desaturation products of t-18:1 have been previously identified in ruminant fat (c9, t12- and c9, t13-18:2). Some of the Δ-9 desaturation products of t-18:1 (c9, t14- and c9, t15-18:2) have been previously tentatively identified as different fatty acids, and for the first time we provide evidence of the presence of c9, t16-18:2, and where t6, c9-18:2 may elute during analysis of FAME from beef fat.
authors.affiliation: Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, T4L 1W1, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Vahmani
authors.affiliation: Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, T4L 1W1, Canada.
authors.forename: D C
authors.initials: DC
authors.lastname: Rolland
authors.affiliation: Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, T4L 1W1, Canada.
authors.forename: K E
authors.initials: KE
authors.lastname: Gzyl
authors.affiliation: Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, T4L 1W1, Canada. mike.dugan@agr.gc.ca.
authors.forename: M E R
authors.initials: ME
authors.lastname: Dugan
mesh_terms: D000818:Animals; D002417:Cattle; D002849:Chromatography, Gas; D005227:Fatty Acids / Q000032:analysis*; D056945:Hep G2 Cells; D006801:Humans; D007536:Isomerism; D000069466:Red Meat / Q000032:analysis*; D013230:Stearoyl-CoA Desaturase / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D013230:Stearoyl-CoA Desaturase
keywords: Gas chromatography; cis/trans 18:2; trans 18:1; Δ-9 desaturation