Identification of cis‐12,cis‐15 octadecadienoic acid and other minor polyenoic fatty acids in ruminant fat

Abstract

Identification of cis-12,cis-15 octadecadienoic acid and other minor polyenoic fatty acids in ruminant fatThe fatty acid pattern of ruminant edible fats is very complex and its diversity is mostly determined by extensive interactions between dietary factors and rumen metabolism. Characterization of intermediates of polyunsaturated fatty acid (PUFA) biohydrogenation in lipids from ruminants, particularly when supplemented with oils, can be a rather difficult task. In this study, we characterized some minor PUFA that occur in muscle samples from linseed oil-fed lambs, by covalent adduct chemical ionization tandem mass spectrometry (CACI-MS/MS) using acetonitrile as reagent of chemical ionization. Two minor metabolites, cis-12,cis-15 18:2 and cis-9,trans-11,cis-15 18:3 were identified for the first time in lamb meat through CACI-MS/MS. However, the cis-9,trans-11,cis-15 18:3 isomer was incompletely resolved from 20:3n-9 under our GC/MS conditions. Thus, in studies reporting biohydrogenation intermediates in meat, caution must be taken in order to ensure proper resolution of these two fatty acid methyl esters (FAME) and therefore avoid quantitative overestimations. CACI-MS/MS was a powerful and rapid method for the structural characterization of minor polyenoic FAME present in ruminant fat, and it seems to be a good alternative to classic 4,4-dimethyloxazoline and picolinyl derivatization methods.

Effect of ensiling and silage additives on fatty acid composition of ryegrass and corn experimental silages1

“…Identification of FA and non-FA compounds was accomplished by using authentic standards and also by GC-MS analysis using a Varian Saturn 2200 system (Varian Inc.). The ion trap parameters used in the present analyses are similar to those described in Alves and Bessa (2007). Additionally, the tandem mass spectrometry technique of covalent adduct chemical ionization (CACI-MS/MS) using acetonitrile as reagent of chemical ionization was used for localization of double bond position of the minor 18:2 isomers.…”

Separation characteristics of fatty acid methyl esters using SLB-IL111, a new ionic liquid coated capillary gas chromatographic column

“…However, there are some overlapping FAMEs that cannot be resolved under any condition using the cyanopropyl siloxane phase columns, and are considered characteristic of this stationary phases' separation of FAs, such as t6-/t7-/t8-18:1, c6-/c7-/c8-18:1, and t7,c9-and c9,t11-18:2, just to name a few FAs. In addition, there are a few coeluting positional and geometric 18:2, 18:3 and 20:1 isomers present in PHVO and ruminant fats that have received little attention and for which only a few reliable standards are available [13,16,19].…”

Isolation of α-linolenic acid biohydrogenation products by combined silver ion solid phase extraction and semi-preparative high performance liquid chromatography

“…BHP with double bonds past carbon 12 from the carboxyl end) have not been extensively characterized [11][12][13][14][15], and may represent an untapped nutraceutical resource.…”