Fatty acids in foods

Patrick, M., Koning, A. J. and Smith, A. B. (1985) Gas liquid chromatographic analysis of fatty acids in food residues from ceramics found in the Southwestern Cape. Archaeomtery 27, 231 236. 

The irradiation of unsaturated fatty acids in foods predominantly results in the formation of a hydroperoxyl radical and then the formation of a hydroperoxide. The hydroperoxides are generally unstable in foods and break down to form mainly carbonyl compounds, many of which have low odor threshold, and contribute to the rancid notes often detected when fat-rich foods are irradiated [18]. In the absence of air, their formation is limited. 

Posati, L. P., Kinsella J.E. and Watt, B. K. 1975. Comprehensive evaluation of fatty acids in foods. I. Dairy products. J. Am. Diet. Assn. 66, 482-489. 

Among many methods proposed for hydrophobic partition, only the method of Shanbhag and Axelsson (1975) is described here. The principle of this method is phase separation by partitioning the hydrophobic upper phase (palmitate is used as it is the most abundant saturated fatty acid in food fat) and the hydrophilic lower phase of proteins. A protein will be separated more into the top layer when it is hydrophobic. The method used by Keshavarz and Nakai (1979), based on Shanbhag and Axelsson (1975), is described in this protocol. 

D1.2 Analysis of Fatty Acids in Food Lipids Basic Protocol 1 Preparation of Fatty Acid Methyl Esters from Lipid Dl.2.1... 

Analysis of Fatty Acids in Food Lipids Equation D1.2.1... 

Sample preparation is probably the most important step in any analytical procedure. Poor preparation of lipid samples will only yield inferior or questionable results. Some commonly performed sample-preparation procedures for gas-liquid chromatographic (GC) analysis of fatty acids in food samples are introduced in this unit. Since the introduction of gas chromatography in the 1950s, significant progress has been made in fatty acid analysis of lipids however, fatty acid methyl esters (FAMEs) are still the most commonly used fatty acid derivative for routine analysis of food fatty acid composition. 

Fatty Acids in Foods and Their Health Implications, edited by Ching Kuang Chow... 

Unsaturated fatty acids in foods are very susceptible to oxidation by oxygen in the air during processing and storage. The oxidation results initially in the formation of fatty acid hydroperoxides by a free radical chain mechanism. The hydroperoxides are subject to several further reactions forming secondary products such as aldehydes, ketones, and other volatile compounds, many of which are odorous and cause rancid flavor in the food. This development of rancid flavor limits the storage stability of a large number of food products. 

Jensen, R.G. 2000. Fatty acids in milk and dairy products. In, Fatty Acids in Foods and their Health Implications. 2nd edn (C.K. Chow, ed.), pp. 109-123, Marcel Dekker Inc., New York, NY. 

Commonly, the fatty acids in food lipids are exposed to heat during oil processing and food manufacture. Once peroxides are formed, they can decompose and generate free radicals, and the rate of peroxide decomposition increases with temperature. Such reactions are of extreme importance to both consumers and processors, because of their flavor significance, and under frying conditions they can affect the physical, nutritional, and toxological properties of the fried food. 

Hoffman, D.R. Patty acids and visual dysfunction. Pood Sci. Technol. 2000, 96. Fatty Acids in Foods and Their Health Implications, 2nd Ed. 817-841. 

The fat in foods contains a mixture of saturated, monounsaturated and polyunsaturated fatty acids. In foods of animal origin, a large proportion of fatty acids are saturated. In contrast, in foods of plant origin and some seafood, a large proportion of the fatty acids are monounsaturated and polyunsaturated. The structures of saturated and unsaturated chemical bonds are shown below. 

Senorans, F. J. and Ibanez, E., Analysis of fatty acids in foods by supercritical fluid chromatography. Anal. Chim. Acta, 465, 131-144, 2002. 

Screw-pressed soybean oils with 1.5 and 2.6% 18 3 (IA2064 and IA3018, respectively), and physically refined, together with a commodity-type soybean oil processed in the same way, were examined during commercial-like frying of French fries. Both 18 3-reduced oils performed better than the commodity oil (Gerde et al., 2007). Other food applications for soybean oils are further explained in the Chapter Food Uses for Soybean Oil and Alternatives to Trans Fatty Acids in Foods. 

Food Uses for Soybean Oil and Alternatives to Trans Fatty Acids in Foods... 

Solid fats have an important function in certain foods, and they differ markedly in their fatty acid profile. Effects on CVD risk status can vary appreciably depending on this profile, and health issues continue to surround the use of solid fats containing saturated and/or trans fatty acids in foods. Recent research by Mensink (2007) indicates that the total fatty acid profile is very important when considering the impact of a solid fat on cardiovascular risk profiles. Foods should therefore be reviewed on an individual basis with respect to amounts of saturated and/or trans fatty acids. As well, consider the specific individual SFA and all other fatty acids in the product. 

Wood, R. 1992. Biological effect of pahn oil humans, in Fatty Acids in Foods and Their Health Implications, Chow, C.K., Ed., New York Marcel Dekker, 647-661. 

LU, Ching Kuang Chow, Fatty Acids in Food and their Health Implications, p. 429 ff.. New York Dekker 1992"Prog. Lipid. 

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