Yeast extract 34281 202570193 2008-04-01T16:06:12Z 129.49.105.59 explained glutamic acid formation '''Yeast extract''' is the common name for various forms of processed [[yeast]] products that are used as food additives or flavourings. They are often used in the same way that [[monosodium glutamate]] (MSG) is used, and, like MSG, often contain free [[glutamic acid]]s. The texture ranges from liquid to a light paste. (Herbst p.681) Glutamic acid in yeast extracts are produced from an acid-base fermentation cycle, only found in some yeasts, typically ones bred for use in baking. ==Autolyzed yeast== '''[[Autolysis (biology)|Autolyzed]] yeast''' or '''autolyzed yeast extract''' consists of concentrations of [[yeast]] cells that are allowed to die and break up, so that the yeasts' [[digestion|digestive]] enzymes break their [[protein]]s down into simpler compounds. Yeast autolysates are used in [[Vegemite]] ([[Australia]]), [[Marmite]], [[Promite]], [[Oxo (food)|Oxo]] ([[New Zealand]], [[South Africa]], [[United Kingdom]], and [[Republic of Ireland]]), and [[Cenovis]] ([[Switzerland]]). [[Bovril]] (The [[United Kingdom]] and [[Republic of Ireland]]) switched from beef extract to yeast extract for 2005 and most of 2006, but later switched back. Autolyzed yeast extract is also the primary source of [[monosodium glutamate]] for the food industry.{{Fact|date=April 2007}} <!-- this statement is either wrong or poorly qualified --> ==Hydrolyzed yeast== '''[[Hydrolysis|Hydrolyzed]] yeast''' or '''hydrolyzed yeast extract''' is another widely used food additive, used for flavouring purposes. ==Manufacture== The general method for making yeast extract for food products such as [[Vegemite]] and [[Marmite]] on a commercial scale is to add salt to a suspension of yeast making the solution hypertonic, which leads to the cells shrivelling up; this triggers [[autolysis]], in which the yeast self-destructs. The dying yeast cells are then heated to complete their breakdown, after which the husks (yeast with thick cell walls which wouldn't do the texture much good) are separated. ==See also== *[[Starch]] [[Category:Food ingredients]] [[Category:Microbiological media ingredients]] [[Category:Yeast extract spreads|*]] [[Category:Umami enhancers]] ==Sources== *{{cite book | last = Herbst | first = Sharon | authorlink = Sharon Herbst | coauthors = | title = Food Lover's Companion | publisher = [[Barron's Educational Series, Inc.]] | date = [[2001]] | location = [[Hauppauge, New York]] | pages = | url = | id = }} [[de:Hefeextrakt]] [[es:Extracto de levadura]] [[ja:酵母エキス]] [[uk:Екстракт дріжджів]]