Implications of Method Chosen for Analysis of Fatty Acids in Meat: A Review

Abstract

The influence of the beef Fatty Acid (FA) profile on human health, has become a recurring concern. For an analysis of the lipid composition of food, it is necessary that the complex lipids be quantified in a suitable form for subsequent analysis of their composition by gas chromatography. The choice of appropriate methods of lipid extraction and esterification of fatty acids, is important in preventing chemical changes from within occurring in these molecules and the forming of artifacts. Among the methods used for quantification of lipids, those that use a mixture of polar and nonpolar solvents separate the lipids in the sample of the non-lipid components. As these methods were carried at ambient temperature, they most suitable for further analysis of the FA profile. These methods were extracted lipids efficiently and did not alter their chemical constitution. The methods of derivation of fatty acids for esterification could be catalyzed by acids or bases. The method was chosen to convert the lipids in Fatty Acid Methyl Esters (FAME) and allow their analysis by gas chromatography, should not lead to incomplete conversion of lipids into their FAME or form artifacts. The reagents commonly used in the transesterification of triacylglycerols in meat samples were the hydroxides of sodium or potassium hydroxide in methanol. Transesterification with these reagents could be developed at room temperature in a short period of time. It becomes a reliable technique for the identification of isomers of fatty acids such as conjugated linoleic acid. No single method performs optimally in all situations. The researcher must know the nature of the sample and select the appropriate method.

Fatty Acids Composition of Vegetable Oils and Its Contribution to Dietary Energy Intake and Dependence of Cardiovascular Mortality on Dietary Intake of Fatty Acids

“…Firstly, fatty acids of oils have to be converted in their methyl esters (FAMEs) before gas chromatography (GC) analyses with a modification according to valid standard method in the Czech Republic [ 69 ] are performed. This method with usage of acid catalyst boron trifluoride is supported by the fact that basic catalysis does not convert free fatty acids especially in oils as can be concluded from the paper [ 70 ]. Briefly, 4 mL of 0.5 M sodium hydroxide in methanol were added to 1 mL oil sample, the equipment was closed and heated for 20 min under nitrogen.…”

Evaluation of Major Fatty Acids Determination in Palm Oil by Gas Chromatography-Flame Ionization Detection

“…One of the basic catalysts commonly used in the derivatization of triacylglycerol is sodium methoxide (NaOCH 3 ) in methanol (Milinsk et al, 2008). Derivatization by using NaOCH 3 in methanol can be implemented at room temperature in a short time (Macedo et al, 2012), but the basic catalyst cannot transform free fatty acids into FAMEs including free fatty acids used as internal standard (Ichihara and Fukubayashi, 2010). Boron trifluoride (BF 3 ) in methanol is one of the most commonly used acid catalysts as a derivatizing agent because this catalyst has high esterifying power (Liu, 1994).…”