Dimer and Trimer Fatty Acids in Feed Fats Characterized by HPLC‐GPC and MS

Abstract

Commercial feed fats, animal fat distillation residue, bleached earth oil and abused fryingfat were fractionated intomonomeric and dimeric triglycerides by means of gel permeation chromatograhy. Upon hydrolysis and methylation the mixtures were analysed by electron impact mass spectre metry using the integrated ion current technique. All samples contained a fraction of dimeric fatty acid methyl ester with molecular ions at m/z 584, 586,588 and 590, probably representing a great variety of both cyclic and linear structures.The individual dimers are not separated by this technique but the mass spectra of the multicomponent dimer fractions of all feed fats investigated showed remarkable resemblance. This may indicate that the dimeric fatty acids generated through intermoleculardimerization between two triglycerides are rather similar to those formed through intramolecular dimerization within the triglycerides. In two cases only trimeric fatty acids methyl esters were observed. The actual concentration of dimeric fatty acids was determined by HPLC-GPC to 3.7-13.70/0.

Production of Fatty Acid Ethyl Esters from Waste Cooking Oil Using Novozym 435 in a Solvent-Free System

“…To predict the average molecular mass of this minor component, a calibration curve was prepared using several monodisperse polystyrene standards, and the estimated apparent average molecular mass was 1020 Da. This is consistent with TAG derivatives, such as hydroperoxides, but in the lower elution volumes of this same distribution, molecules in the range of 1800–2000 Da were also detected and could be attributed to TAG dimers, as already observed by other authors in WCO samples. ,− …”

Nuclear Magnetic Resonance and Gas Chromatography/Mass Spectroscopy Analysis of the Nonvolatile Components Produced during Heating of Oleic Acid Esterified Propoxylated Glycerol, a Fat Substitute Model Compound, and Trioleylglycerol

“…Chang et al (1978) isolated a noncyclic carbonyl dimeric FAME, after derivatization, from heated triolein. MeOL dimeric FAMEs are formed from free radical reactions and not from the Diels-Alder reaction (Jensen and Møller, 1986).…”

Mass spectrometric detection of cross-linked fatty acids formed during radical-induced lesion of lipid membranes

“…(Nelson & Milun, 1975), h.p.l.c. (Veazey, 1986;Zeman et al, 1986) and gel-permeation chromatography (Inoue et al, 1970;Harris et al, 1973;Jensen & Moller, 1986). Sen Gupta (1969) found that heating of methyl linolenate to 280°C under high vacuum gives rise to dimers with more than one carbon-carbon bridge, while peroxide-induced dimerization at 140°C entails mainly acyclic dimers.…”