Yeast extract
Encyclopedia
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
products made by extracting the cell contents (removing the cell walls); they are used as food additives or flavourings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami
Umami
Umami , popularly referred to as savoriness, is one of the five basic tastes together with sweet, sour, bitter, and salty.-Etymology:Umami is a loanword from the Japanese meaning "pleasant savory taste". This particular writing was chosen by Professor Kikunae Ikeda from umai "delicious" and mi ...
taste sensations. Monosodium glutamate
Monosodium glutamate
Monosodium glutamate, also known as sodium glutamate or MSG, is the sodium salt of glutamic acid, one of the most abundant naturally occurring non-essential amino acids....
(MSG) is used for umami. Yeast extract, like MSG, often contains free glutamic acid
Glutamic acid
Glutamic acid is one of the 20 proteinogenic amino acids, and its codons are GAA and GAG. It is a non-essential amino acid. The carboxylate anions and salts of glutamic acid are known as glutamates...
. Yeast extracts in liquid form can be dried to a light paste or a dry powder. 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
AutolyzedAutolysis (biology)
In biology, autolysis, more commonly known as self-digestion, refers to the destruction of a cell through the action of its own enzymes. It may also refer to the digestion of an enzyme by another molecule of the same enzyme....
yeast (containing the cell walls) or autolyzed yeast extract consists of concentrations of yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
cells that are allowed to die and break up, so that the yeasts’ endogenous digestive
Digestion
Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
enzymes break their protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s down into simpler compounds (amino acids and peptides).
Yeast autolysates are used in Vegemite
Vegemite
Vegemite is a dark brown Australian food paste made from yeast extract. It is a spread for sandwiches, toast, crumpets and cracker biscuits, and filling for pastries...
(Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
), Marmite
Marmite
Marmite is the name given to two similar food spreads: the original British version, first produced in the United Kingdom and later South Africa, and a version produced in New Zealand...
, Promite
Promite
Promite is the registered brand name for a dark brown, salty food paste mainly used as a spread on sandwiches and toast similar to the better known Vegemite and Marmite. Promite was invented in the 1950s by Dr. David Lewis of the family food company Henry Lewis & Company and marketed under the...
, Oxo
Oxo (food)
Oxo is a range of food products, consisting of stock cubes, herbs and spices, dried gravy, and yeast extract. In the United Kingdom, Oxo products are manufactured by Premier Foods...
(New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, and Republic of Ireland
Republic of Ireland
Ireland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,...
), Cenovis
Cenovis
Cenovis is a product based on yeast extract similar to Marmite and Vegemite, rich in vitamin B1. In the form of a dark brown food paste, it is used to flavour soups, sausages, and salads. The most popular way to consume Cenovis is however to spread it on a slice of buttered bread, as stated on the...
(Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
) and Vitam-R (Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
). Bovril
Bovril
Bovril is the trademarked name of a thick, salty meat extract, developed in the 1870s by John Lawson Johnston and sold in a distinctive, bulbous jar. It is made in Burton upon Trent, Staffordshire, owned and distributed by Unilever UK....
(United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
and Republic of Ireland
Republic of Ireland
Ireland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,...
) switched from beef extract to yeast extract for 2005 and most of 2006, but later switched back.
The general method for making yeast extract for food products such as Vegemite
Vegemite
Vegemite is a dark brown Australian food paste made from yeast extract. It is a spread for sandwiches, toast, crumpets and cracker biscuits, and filling for pastries...
and Marmite
Marmite
Marmite is the name given to two similar food spreads: the original British version, first produced in the United Kingdom and later South Africa, and a version produced in New Zealand...
on a commercial scale is to add sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
(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) are separated. Removing the cell walls concentrates the flavors and changes the texture.
Hydrolyzed yeast
HydrolyzedHydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
yeast or hydrolyzed yeast extract is another version used as a food additive for flavouring purposes. Exogenous enzymes or acids are used to hydrolyze the proteins.