– Composition of common fats:
– Fats broken down to constituent fatty acids for analysis.
– Fats undergo transesterification to give FAMEs for quantitation.
– Unsaturated isomers separated by argentation thin-layer chromatography.
– Saturated fatty acid components mainly stearic and palmitic acids.
– Monounsaturated fats mainly oleic acid.
– Chemistry and nutrition:
– Polyunsaturated fats protective against cardiac arrhythmias.
– Study showed polyunsaturated fat positively associated with atherosclerosis progression.
– Unsaturated fatty acids include palmitoleic, oleic, linoleic, and arachidonic acid.
– FDA recommends unsaturated fat intake not exceed 30% of daily caloric intake.
– Most foods contain both unsaturated and saturated fats.
– Membrane composition as a metabolic pacemaker:
– Mammalian cell membranes have higher polyunsaturated fatty acid proportion than reptiles.
– Bird fatty acid composition similar to mammals but with fewer omega-3 fatty acids.
– More fluid cell membranes in mammals and birds due to fatty acid composition.
– Cold temperatures lead to increased polyunsaturation of fish cell membranes.
– High metabolic rates in mammals and birds due to costly maintenance of cell membranes.
– See also:
– Unsaturated fat definition in Wiktionary.
– Iodine value used to determine unsaturated fat proportion.
– List of unsaturated fatty acids.
– References:
– Optimization of extraction of fatty acids and polyphenols from grape wastes.
– Separation of fatty acids by alumina argentation thin-layer chromatography.
– Information on fats and fatty oils.
– Studies on dietary fats and coronary atherosclerosis.
– Dietary supplements protecting against lipid peroxidation.
An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.
A saturated fat has no carbon to carbon double bonds, so the maximum possible number of hydrogens bonded to the carbons, and is "saturated" with hydrogen atoms. To form carbon to carbon double bonds, hydrogen atoms are removed from the carbon chain. In cellular metabolism, unsaturated fat molecules contain less energy (i.e., fewer calories) than an equivalent amount of saturated fat. The greater the degree of unsaturation in a fatty acid (i.e., the more double bonds in the fatty acid) the more vulnerable it is to lipid peroxidation (rancidity). Antioxidants can protect unsaturated fat from lipid peroxidation.