Editing Lecithin (section)

{{short description|Generic term for amphiphilic substances of plant and animal origin}}
{{Distinguish|Lectin}}
{{cs1 config|name-list-style=vanc}}
[[Image:1-Oleoyl-2-almitoyl-phosphatidylcholine Structural Formulae V.1.png|class=skin-invert-image|thumb|300px|An example of a [[phosphatidylcholine]], a type of [[phospholipid]] in lecithin. Shown in {{color|#800000|red}} – [[choline]] residue and [[phosphate]] group; {{color|light-dark(black,white)|black}} – [[glycerol]] residue; {{color|#008000|green}} – [[monounsaturated fatty acid]] residue; {{color|light-dark(#000080,skyblue)|blue}} – [[saturated fatty acid]] residue.]]
[[File:Lecithin-Formulierungen.jpg|thumb|The different forms of lecithin – powder, two different concentration liquids, granular and powder lecithin]]
'''Lecithin''' ({{IPAc-en|ˈ|l|ɛ|s|ɪ|θ|ɪ|n}} {{respell|LESS|ith|in}}; from the [[Ancient Greek]] {{lang|grc|λέκιθος}} {{Transliteration|grc|lékithos}} "[[yolk]]") is a generic term to designate any group of yellow-brownish [[lipid|fatty]] substances occurring in animal and plant tissues which are [[amphiphilic]] – they attract both water and fatty substances (and so are both [[hydrophilic]] and [[lipophilic]]), and are used for smoothing food textures, [[Emulsion|emulsifying]], [[Homogenization (chemistry)|homogenizing]] liquid mixtures, and repelling sticking materials.<ref>{{cite web |url=http://www.merriam-webster.com/dictionary/lecithin |title=Lecithin |website=Merriam Webster Dictionary Online |access-date=2015-11-18 |archive-date=2018-06-12 |archive-url=https://web.archive.org/web/20180612210956/https://www.merriam-webster.com/dictionary/lecithin |url-status=live }}</ref><ref>{{cite book |chapter-url=https://books.google.com/books?id=_2Vgsk7o9LsC&pg=PA109|title=Lecithins: Sources, Manufacture & Uses|first=Bernard F.|last=Szuha|publisher=The American Oil Chemist's Society |isbn=0-935315-27-6|chapter=Chapter 7|page=109|year=1989}}</ref>

Lecithins are mixtures of [[glycerophospholipid]]s including [[phosphatidylcholine]], [[phosphatidylethanolamine]], [[phosphatidylinositol]], [[phosphatidylserine]], and [[phosphatidic acid]].<ref>{{cite book|editor1-last=Smith |editor1-first=Jim|editor2-last=Hong-Shum|editor2-first=Lily|title=Food Additives Data Book |date=2011 |publisher=Wiley-Blackwell |location=Chichester, West Sussex |isbn=978-1-4443-9773-4 |page=334 |edition=2nd |quote=Complex mixture of phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidic acid, glycolipids, etc.}}</ref>

Lecithin was first isolated in 1845 by the French chemist and pharmacist [[Theodore Nicolas Gobley|Théodore Gobley]].<ref>{{cite journal
 |last=Gobley |first=Théodore |year=1846
 |title=Recherches chimiques sur le jaune d'œuf |trans-title=Chemical researches on egg yolk
 |journal=Journal de Pharmacie et de Chemie |series=3rd series |volume=9 |pages=81–91
 |url=https://books.google.com/books?id=DC04AAAAMAAJ&pg=PA84 |language=fr}}</ref> In 1850, he named the phosphatidylcholine {{lang|fr|lécithine}}.<ref>{{cite journal
 |last=Gobley |first=Théodore |year=1850
 |title=Recherches chimiques sur les œufs de carpe |trans-title=Chemical researches on carp eggs
 |journal=Journal de Pharmacie et de Chemie |series=3rd series |volume=17 |pages=401–430
 |url=https://books.google.com/books?id=vQVCAAAAcAAJ&pg=PA411 |language=fr
 |quote=''Je propose de donner au premier le nom de ''Lécithine'' (de λεκιθος, jaune d'œuf), parce qu'on le rencontre en grande quantité dans le jaune d'œuf'' ... (I propose to give to the former the name of ''lecithin'' (from λεκιθος, egg yolk), because it is encountered in great quantity in egg yolk ... )}}</ref> Gobley originally isolated lecithin from [[egg yolk]] and established the complete chemical formula of phosphatidylcholine in 1874;<ref>{{cite journal
 |title=Sur la lécithine et la cérébrine |trans-title=On lecithin and cerebrin |year=1874
 |first=Théodore |last=Gobley
 |journal=Journal de Pharmacie et de Chimie |series=4th series |volume=19 |pages=346–353
 |url=https://books.google.com/books?id=ypdGAQAAMAAJ&pg=PA346 |language=fr}}</ref> in between, he demonstrated the presence of lecithin in a variety of biological materials, including [[venous blood]], human lungs, [[bile]], [[roe]], and [[brain]]s of humans, sheep and chicken.

Lecithin can easily be extracted chemically using solvents such as [[hexane]], [[ethanol]], [[acetone]], [[petroleum ether]] or [[benzene]]; or extraction can be done mechanically. Common sources include egg yolk,<ref name="WebMD on lecithin 2019"/> marine foods, [[soybean]]s,<ref name="WebMD on lecithin 2019">{{cite web | title=Lecithin: Uses, Side Effects, Interactions, Dosage, and Warning | website=WebMD | date=2019-01-30 | url=https://www.webmd.com/vitamins/ai/ingredientmono-966/lecithin | access-date=2019-06-18 | archive-date=2019-06-18 | archive-url=https://web.archive.org/web/20190618051017/https://www.webmd.com/vitamins/ai/ingredientmono-966/lecithin | url-status=live }}</ref> milk, [[rapeseed]], [[cottonseed]], and [[sunflower oil]]. It has low [[solubility]] in water, but is an excellent [[emulsifier]]. In aqueous solution, its [[phospholipid]]s can form either [[liposome]]s, [[Lipid bilayer|bilayer sheets]], [[micelle]]s, or [[lamellar structure]]s, depending on hydration and temperature. This results in a type of [[surfactant]] that usually is classified as [[amphipathic]]. Lecithin is sold as a [[food additive]] and [[dietary supplement]]. In cooking, it is sometimes used as an emulsifier and to prevent sticking, for example in [[non-stick cooking spray]].