267 Virgin Olive Oil Benefits acid (C18:2 ω6) and linolenic acid (C18:3 ω3). These are mainly found in oily fish, nuts, seed oils, olive oil, and fish oil. Arachidonic acid (C20:4 ω6), eicosapentaenoic acid -EPA- (C20:5 ω3), and docosahexaenoic acid -DHA- (C22:6 ω3) also play important physiological roles, although they are not classified as essential because the body can synthesise them from linoleic (ω6) and linolenic (ω3) acids. However, the body produces only small amounts of omega-3 derivatives, which makes it advisable to include them in the diet. EPA and DHA are present in significant quantities in oily fish (approximately 1 g of ω-3 fatty acids per 100 g of food). · free fatty acids Isolated fatty acids that are not linked or combined with glycerol or other alcohols. They are present in blood plasma as a result of food digestion or fat mobilisation from adipose tissue (lipolysis), through the action of various hormones. In the bloodstream, they circulate bound to albumin to be used as energy substrates, eliminated by the liver, or reused in the synthesis of glycerides and other compounds. Within cells, when released from phospholipids, they may be involved in cell signalling or serve as precursors for the synthesis of other molecules, such as arachidonic acid in the production of eicosanoids. Free fatty acids are scarce in food and are generally the result of lipid degradation. · free fatty acid desaturases Enzymes that introduce double bonds into the hydrocarbon chain (carbons -C- and hydrogens -H-) of fatty acids, resulting in the formation of monounsaturated and polyunsaturated fatty acids. · double bond/s In general, bonds are the forces that hold atoms together to form molecules and compounds. A double bond in chemistry is a covalent bond between two atoms. A covalent bond can be defined as a chemical bond in which two atoms share electrons, forming a unit called a molecule. In a double bond, four electrons are involved instead of the two found in a single bond. It is usually represented by two parallel lines in chemical structure diagrams (e.g. H₂C=CH₂). Double bonds most commonly occur between two carbon atoms, and they are stronger and shorter than single bonds. Oils become rancid because the double bonds in unsaturated fatty acids react with oxygen in the air and undergo oxidation. When this occurs, the double bond breaks and the molecule splits, forming aldehydes. Antioxidants, such as those found in the minor components of virgin olive oil, protect against this oxidation. In refined olive oils, these compounds are largely removed during industrial processing, which is why they are more prone to rancidity. · esterification; esterified The chemical reaction between an alcohol and a carboxylic acid is called esterification, and the product obtained is an ester, with water released. acid + alcohol ester + water See also under “CONCEPTS” the formation of glycerides from glycerol (alcohol) and fatty acids (acid). ………………………………………………………………………………………………
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