Polyunsaturated+fat

Saturated fats have hydrocarbon chains which can be most readily aligned. The hydrocarbon chains in trans fats align more readily than those in cis fats, but less well than those in saturated fats. This means that, in general, the melting points of fats increase from cis to trans unsaturated and then to saturated. See the section on [|chemical structure of fats] for more information. Chemical structure of the polyunsaturated fat [|linoleic acid]. 3D representation of [|linoleic acid] in a bent [|conformation]. The position of the carbon-carbon double bonds in [|carboxylic acid] chains in fats is designated by [|Greek letters]. The carbon atom closest to the [|carboxyl group] is the //alpha// carbon, the next carbon is the //beta// carbon and so on. In fatty acids the carbon atom of the [|methyl group] at the end of the hydrocarbon chain is called the //omega// carbon because //omega// is the last letter of the Greek alphabet. [|Omega-3 fatty acids] have a double bond three carbons away from the methyl carbon, whereas [|omega-6 fatty acids] have a double bond six carbons away from the methyl carbon. The illustration below shows the omega-6 fatty acid, [|linoleic acid]. While the nutritional aspects of polyunsaturated fats are of highest concern, these materials do have non-food applications. [|Drying oils], which [|polymerize] on exposure to [|oxygen] to form solid films, are polyunsaturated fats. The most common ones are [|linseed (flax seed) oil], [|tung oil], [|poppy seed oil], [|perilla oil], and [|walnut oil]. These oils are used to make [|paints] and [|varnishes].
 * Polyunsaturated fats** are [|triglycerides] in which the [|fatty acid] part of the [|ester] is [|polyunsaturated fatty acid] (PUFA) (fatty acids with more than one carbon–carbon [|double bond]).[|[1]][|[2]] "Unsaturated" refers to the fact that the molecules contain less than the maximum amount of hydrogen. These materials exist as //[|cis]// or //[|trans]// [|isomers] depending on the geometry of the double bond.