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Yeasts
Yeast of the species Saccharomyces cerevisiae.
Yeast of the species Saccharomyces cerevisiae.
Scientific classification
Domain: Eukaryota
Kingdom: Fungi
Typical divisions

Yeasts are a growth form of eukaryotic microorganisms classified in the kingdom Fungi, with about 1,500 species described;[1] they dominate fungal diversity in the oceans. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Ascomycota is a Division / Phylum of Fungi, and subkingdom Dikarya, whose members are commonly known as the Sac Fungi. Saccharomycotina is a subphylum of the phylum Ascomycota (fungi which form their sexual spores in sac-like asci) and consists of Yeasts - they form Taphrinomycotina is one of three subphyla constituting the Ascomycota (fungi that form their Spores in a sac-like Ascus) and is more or less synonymous Schizosaccharomycetes is a class in the kingdom of Fungi. It contains the order Schizosaccharomycetales, the fission Yeasts Basidiomycota is one of two large phyla that together with the Ascomycota, comprise the subkingdom Dikarya, which were in general what were called Urediniomycetes is a diverse class of Fungi that includes several important plant pathogens causing forms of fungal rust. Sporidiales is an order in the kingdom of Fungi. It contains the family Sporidiobolaceae. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually In biological Taxonomy, a kingdom or regnum is a Taxonomic rank in either (historically the highest rank or (in the new three-domain system A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. [2] Most reproduce asexually by budding, although a few do by binary fission. Asexual reproduction is a form of reproduction which does not involve Meiosis, Ploidy reduction or Fertilization. Budding (also called burgeoning) is the formation of a new Organism by the protrusion of part of another organism Binary fission is the form of Asexual reproduction and Cell division used by Prokaryotic organisms (such as Bacteria or Archea) Yeasts are unicellular, although some species with yeast forms may become multicellular through the formation of a string of connected budding cells known as pseudohyphae, or false hyphae as seen in most molds. A hypha (plural hyphae) is a long branching filamentous cell of a Fungus, and also of unrelated Actinobacteria. A hypha (plural hyphae) is a long branching filamentous cell of a Fungus, and also of unrelated Actinobacteria. WikipediaManual_of_Style#National_varieties_of_English --> Molds (or [3] Yeast size can vary greatly depending on the species, typically measuring 3–4 µm in diameter, although some yeasts can reach over 40 µm. A micrometre ( American spelling: micrometer; symbol µm) is one millionth of a Metre, or equivalently one thousandth of a Millimetre Geometry, a diameter of a Circle is any straight Line segment that passes through the center of the circle and whose Endpoints are on the [4]

The yeast species Saccharomyces cerevisiae has been used in baking and fermenting alcoholic beverages for thousands of years. Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times Baking is the technique of prolonged Cooking of Food by dry heat acting by conduction, and not by radiation, normally in an Oven, Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions It is also extremely important as a model organism in modern cell biology research, and is the most thoroughly researched eukaryotic microorganism. A model organism is a Species that is extensively studied to understand particular biological Phenomena, with the expectation that discoveries made See also List of basic cell biology topics. Cell biology (also called cellular biology or formerly cytology, from the Researchers have used it to gather information into the biology of the eukaryotic cell and ultimately human biology. [5] Other species of yeast, such as Candida albicans, are opportunistic pathogens and can cause infection in humans. Candida albicans is a Diploid Fungus (a form of Yeast) which is capable of mating but not of Meiosis, and a causal agent of An opportunistic infection is an infection caused by Pathogens that usually do not cause disease in a healthy Immune system. Candidiasis, commonly called yeast infection or thrush, is a Fungal infection (mycosis of any of the Candida species of which Yeasts have recently been used to generate electricity in microbial fuel cells,[6] and produce ethanol for the biofuel industry. A microbial fuel cell ( MFC) or biological fuel cell is a bio- Electrochemical system that drives a current by mimicking Bacterial interactions

Yeasts do not form a specific taxonomic or phylogenetic grouping. Taxonomy is the practice and science of classification The word comes from the Greek, taxis (meaning 'order' 'arrangement' and, nomos At present it is estimated that only 1% of all yeast species have been described. [7] The term "yeast" is often taken as a synonym for S. This article deals with the general meaning of the term "synonym" cerevisiae,[8] however the phylogenetic diversity of yeasts is shown by their placement in both divisions Ascomycota and Basidiomycota. Ascomycota is a Division / Phylum of Fungi, and subkingdom Dikarya, whose members are commonly known as the Sac Fungi. Basidiomycota is one of two large phyla that together with the Ascomycota, comprise the subkingdom Dikarya, which were in general what were called The budding yeasts ("true yeasts") are classified in the order Saccharomycetales. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Saccharomycetales is an order in the kingdom of Fungi that comprises the budding Yeasts [9]

Contents

History

See also: History of wine and History of beer

The word "yeast " comes from the Old English language "gist", "gyst", and ultimately from the Indo-European root "yes-", meaning boil, foam, or bubble. The history of Wine spans thousands of years and is closely intertwined with the history of Agriculture, Cuisine, Civilization and See also Beer Beer is one of the world's oldest beverages with the history of beer dating back to the 6th millennium BC and being recorded in the written history of [10] Yeast microbes are probably one of the earliest domesticated organisms. People have used yeast for fermentation and baking throughout history. Archaeologists digging in Egyptian ruins found early grinding stones and baking chambers for yeasted bread, as well as drawings of 4,000-year-old bakeries and breweries. [11] In 1680 the Dutch naturalist Antoine van Leeuwenhoek first microscopically observed yeast, but at the time did not consider them to be living organisms but rather globular structures. The Dutch people ( Dutch:) are the dominant Ethnic group of the Netherlands. Antonie Philips van Leeuwenhoek (October 24 1632 &ndash August 30 1723 was a Dutch tradesman and Scientist from Delft, the Netherlands Microscopy is the technical field of using microscopes to view samples or objects [12] In 1857 French microbiologist Louis Pasteur proved in the paper "Mémoire sur la fermentation alcoolique" that alcoholic fermentation was conducted by living yeasts and not by a chemical catalyst. Legal residents and citizens To be French according to the first article of the Constitution is to be a citizen of France regardless of one's origin race or religion ( Louis Pasteur (27 December 1822 – 28 September 1895 a French Chemist and Microbiologist, is best known for remarkable breakthroughs in the causes and [11][13] Pasteur showed that by bubbling oxygen into the yeast broth, cell growth could be increased, but the fermentation inhibited - an observation later called the Pasteur effect. The Pasteur effect is an inhibiting effect of Oxygen on the fermentation process

In the United States, naturally occurring airborne yeasts (as in sourdough bread) were used almost exclusively until commercial yeast was marketed at the Centennial Exposition in 1876 in Philadelphia, where Charles L. Fleischmann exibited the product and a process to use it, as well as serving the resultant baked bread. Sourdough (or more formally natural leaven or Levain) refers to the process of leavening Bread by capturing wild Yeasts

Growth and nutrition

Yeasts are chemoorganotrophs as they use organic compounds as a source of energy and do not require sunlight to grow. Chemoorganotrophs utilize Organic compounds as their Energy source An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. The main source of carbon is obtained by hexose sugars such as glucose and fructose, or disaccharides such as sucrose and maltose. In Organic chemistry, a hexose is a Monosaccharide with six Carbon atoms having the Chemical formula C6H12O6 Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Fructose (also levulose or laevulose) is a simple reducing Sugar ( Monosaccharide) found in many foods and is one of the three Solubility of Pure SucroseTemperature(Cg Maltose, or malt sugar is a Disaccharide formed from two units of Glucose joined with an α(1→4 linkage Some species can metabolize pentose sugars, alcohols, and organic acids. A pentose is a Monosaccharide with five Carbon Atoms They either have an Aldehyde Functional group in position 1 ( aldopentoses In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon An organic acid is an Organic compound with Acidic properties Yeast species either require oxygen for aerobic cellular respiration (obligate aerobes), or are anaerobic but also have aerobic methods of energy production (facultative anaerobes). Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from An aerobic organism or aerobe is an Organism that has an Oxygen based Metabolism. A facultative anaerobic organism is an Organism, usually a Bacterium, that makes ATP by Aerobic respiration if Oxygen is present Unlike bacteria, there are no known yeast species that grow only anaerobically (obligate anaerobes). The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have An anaerobic organism is any Organism that does not require Oxygen for growth and may even die in its presence Yeasts grow best in a neutral or slightly acidic pH environment.

Yeasts will grow over a temperature range of 10°-37°C (50°-98. 6°F), with an optimal temperature range of 30°-37°C (86°-98. 6°F), depending on the type of species. S.  cerevisiae works best at about 30°C. There is little activity in the range of 0°-10°C. Above 37°C yeast cells become stressed and will not divide properly. Most yeast cells die above 50°C (122°F). The cells can survive freezing under certain conditions, with viability decreasing over time.

Yeasts are ubiquitous in the environment, but are most frequently isolated from sugar-rich samples. Some good examples include fruits and berries (such as grapes, apples or peaches), and exudates from plants (such as plant saps or cacti). For the Tokyo University supercomputer see Gravity Pipe. GRAPE, or GRA phics P rogramming E nvironment is The apple is the pomaceous Fruit of the apple tree Species Malus domestica in the Rose family Rosaceae. The peach ( Prunus persica) is a species of Prunus native to China that bears an edible juicy fruit also called a peach Some yeasts are found in association with soil and insects. [14][15] Yeast are generally grown in the laboratory on solid growth media or liquid broths. A growth medium or culture medium is a liquid or gel designed to support the growth of Microorganisms or cells There are different types of media for Broth is a Liquid in which Bones Meat, Fish, Cereal grains or Vegetables have been simmered and strained out Common media used for the cultivation of yeasts include; potato dextrose agar (PDA) or potato dextrose broth, Wallerstien Laboratories Nutrient agar (WLN), Yeast Peptone Dextrose agar (YPD), and Yeast Mould agar or broth (YM). Potato dextrose agar (FDA M127(abbreviated "PDA" and potato dextrose broth (abbreviated "PDB" are common microbiological media made from potato infusion and dextrose Peptides (from the Greek πεπτίδια, "small digestibles" are short Polymers formed from the linking in a defined order of α- Amino Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. The antibiotic cycloheximide is sometimes added to yeast growth media to inhibit the growth of Saccharomyces yeasts and select for wild/indigenous yeast species. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa Cycloheximide is an inhibitor of Protein biosynthesis in eukaryotic organisms produced by the bacterium Streptomyces griseus

Reproduction

The yeast cell's life cycle. 1. Budding 2. Conjugation 3. Spore
The yeast cell's life cycle.
1. Budding
2. Conjugation
3. Spore
See also: Mating of yeast

Yeasts have asexual and sexual reproductive cycles; however the most common mode of vegetative growth in yeast is asexual reproduction by budding or fission. The yeast Saccharomyces cerevisiae is a simple single celled Eukaryote with both a Diploid and Haploid mode of existence Asexual reproduction is a form of reproduction which does not involve Meiosis, Ploidy reduction or Fertilization. The Evolution of sexual reproduction is a major puzzle The first Fossilized evidence of sexually reproducing Organisms is from Eukaryotes of the Stenian Asexual reproduction is a form of reproduction which does not involve Meiosis, Ploidy reduction or Fertilization. Budding (also called burgeoning) is the formation of a new Organism by the protrusion of part of another organism Binary fission is the form of Asexual reproduction and Cell division used by Prokaryotic organisms (such as Bacteria or Archea) [16] Here a small bud, or daughter cell, is formed on the parent cell. The nucleus of the parent cell splits into a daughter nucleus and migrates into the daughter cell. In Cell biology, the nucleus (pl nuclei; from Latin la ''nucleus'' or la ''nuculeus'' "little nut" or kernel is a membrane-enclosed The bud continues to grow until it separates from the parent cell, forming a new cell. [17] The bud can develop on different parts of the parent cell depending on the genus of the yeast. A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic Yeast needs the exact chemical form of sugar and cannot reproduce with sugar substitutes. However if the sugar substitute's chemical form is similar to sugar, yeast will reproduce a bit compared with many sugar substitutes where yeast will not reproduce at all.

Under high stress conditions haploid cells will generally die, however under the same conditions diploid cells can undergo sporulation, entering sexual reproduction (meiosis) and producing a variety of haploid spores, which can go on to mate (conjugate), reforming the diploid. "Haplo" redirects here For the fictional character see The Death Gate Cycle. "Haplo" redirects here For the fictional character see The Death Gate Cycle. In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half In Biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions The yeast Saccharomyces cerevisiae is a simple single celled Eukaryote with both a Diploid and Haploid mode of existence "Haplo" redirects here For the fictional character see The Death Gate Cycle. [18]

Yeast of the species Schizosaccharomyces pombe reproduce by binary fission instead of budding. Schizosaccharomyces pombe, also called "fission yeast" is a Species of Yeast. Binary fission is the form of Asexual reproduction and Cell division used by Prokaryotic organisms (such as Bacteria or Archea) [16]

Uses

The useful physiological properties of yeast have led to their use in the field of biotechnology. Biotechnology is Technology based on Biology, especially when used in Agriculture, Food science, and Medicine. Fermentation of sugars by yeast is the oldest and largest application of this technology. Fermentation is the process of deriving energy from the oxidation of organic compounds such as carbohydrates using an endogenous electron acceptor which is Many types of yeasts are used for making many foods: Baker's yeast in bread production, brewer's yeast in beer fermentation, yeast in wine fermentation and for xylitol[19] production. Bread is a Staple food prepared by Baking a Dough of Flour and Water. Beer is the world's oldest and most widely consumed Alcoholic beverage and the third most popular drink overall after water and tea Wine is an Alcoholic beverage made from the fermentation of Grape juice Xylitol (from Greek ξύλον - xyl, "wood" + suffix - itol, used to denote sugar alcohols is an Organic compound with the formula (CHOH3(CH2OH2 Yeasts are also one of the most widely used model organisms for genetics and cell biology. A model organism is a Species that is extensively studied to understand particular biological Phenomena, with the expectation that discoveries made Genetics (from Ancient Greek grc-Latn genetikos, “genitive” and that from grc-Latn genesis, “origin” a discipline of Biology, is See also List of basic cell biology topics. Cell biology (also called cellular biology or formerly cytology, from the

Alcoholic beverages

Alcoholic beverages are loosely defined as a beverage that contains ethanol (C2H5OH). A drink, or beverage, is a Liquid specifically prepared for Human consumption This ethanol is almost always produced by fermentation - the metabolism of carbohydrates by certain species of yeast. Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Carbohydrates (from ' Hydrates of Carbon ' or saccharides ( Greek σάκχαρον meaning " Sugar " are the most Beverages such as wine, beer, or distilled spirits all use yeast at some stage of their production. Wine is an Alcoholic beverage made from the fermentation of Grape juice Beer is the world's oldest and most widely consumed Alcoholic beverage and the third most popular drink overall after water and tea

Beer

A mixture of diatomaceous earth and yeast after filtering beer.
A mixture of diatomaceous earth and yeast after filtering beer. Diatomaceous earth (ˌdaɪətəˈmeɪʃəs ˈɝθ also known as DE, TSS, diatomite, diahydro, kieselguhr, kieselgur and Beer is the world's oldest and most widely consumed Alcoholic beverage and the third most popular drink overall after water and tea

Beer brewers classify yeasts as top-fermenting and bottom-fermenting. Brewing is the production of Alcoholic beverage and Alcohol fuel through fermentation. This distinction was introduced by the Dane Emil Christian Hansen. The term Dane may refer to People with a Danish ancestral or ethnic identity whether living in Denmark, emigrants or the descendants of emigrants Emil Christian Hansen ( May 8, 1842 – August 27, 1909) was a Danish Mycologist and fermentation physiologist Top-fermenting yeasts are so called because they form a foam at the top of the wort during fermentation. WORT (899 FM is a listener-sponsored community radio station broadcasting from 118 S They can produce higher alcohol concentrations and prefer higher temperatures, producing fruitier ale-type beers. Ale is a type of Beer brewed from Malted Barley using a top-fermenting Brewers' yeast. An example of a top-fermenting yeast is Saccharomyces cerevisiae, known to brewers as ale yeast. Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times Ale is a type of Beer brewed from Malted Barley using a top-fermenting Brewers' yeast. Bottom-fermenting yeasts are used to produce lager-type beers. Lager (storage camp bearing etc is the more popular of two main types of Beer; the other being Ale. These yeasts ferment more sugars, leaving a crisper taste, and grow well at low temperatures. An example of a bottom-fermenting yeast is Saccharomyces pastorianus. Saccharomyces pastorianus is a Yeast, used industrially for the production of Lager beer

For both types, yeast is fully distributed through the beer while it is fermenting, and both equally flocculate (clump together and precipitate to the bottom of the vessel) when it is finished. Flocculation is a process where a Solute comes out of Solution in the form of floc or flakes By no means do all top-fermenting yeasts demonstrate this behaviour, but it features strongly in many English ale yeasts which may also exhibit chain forming (the failure of budded cells to break from the mother cell) which is technically different from true flocculation.

Lambic, a style of Belgian beer, is fermented spontaneously by wild yeasts primarily of the genus Brettanomyces. Lambic is a very distinctive type of Beer brewed only in the Pajottenland region of Belgium (southwest of Brussels) The Kingdom of Belgium is a Country in northwest Europe. It is a founding member of the European Union and hosts its headquarters as well as those Brettanomyces is a non-spore forming genus of Yeast in the family Saccharomycetaceae, and is often colloquially referred to as "

Fermenting tanks with yeast being used to brew beer.
Fermenting tanks with yeast being used to brew beer. Brewing is the production of Alcoholic beverage and Alcohol fuel through fermentation. Beer is the world's oldest and most widely consumed Alcoholic beverage and the third most popular drink overall after water and tea

In industrial brewing, to ensure purity of strain, a 'clean' sample of the yeast is stored refrigerated in a laboratory. After a certain number of fermentation cycles, a full scale propagation is produced from this laboratory sample. Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions Reproduction is the Biological process by which new individual Organisms are produced Typically, it is grown up in about three or four stages using sterile brewing wort and oxygen. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the

Root Beer and Sodas

Root beer and other sweet carbonated beverages can be produced using the same methods as beer, except that fermentation is stopped sooner, producing carbon dioxide, but only trace amounts of alcohol, and a significant amount of sugar is left in the drink.

Distilled beverages

A distilled beverage is a beverage that contains ethanol that has been purified by distillation. Distillation is a method of separating Mixtures based on differences in their volatilities in a boiling liquid mixture Carbohydrate-containing plant material is fermented by yeast, producing a dilute solution of ethanol in the process. Spirits such as whiskey and rum are prepared by distilling these dilute solutions of ethanol. Whisky (uisge-beatha or whiskey (uisce beatha or fuisce) refers to a broad category of Alcoholic beverages that are distilled from fermented Rum is a Distilled beverage made from Sugarcane by-products such as Molasses and sugarcane Juice by a process of fermentation Components other than ethanol are collected in the condensate, including water, esters, and other alcohols which account for the flavor of the beverage. Esters are a class of Chemical compounds and Functional groups Esters consist of an inorganic or organic Acid in which at least In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon Flavor or flavour is the sensory impression of a Food or other substance, and is determined

Wine

Fresh grapes
Fresh grapes
Main article: Fermentation (wine)

Yeast is used in winemaking where it converts the sugars present in grape juice or must into alcohol. The process of fermentation in Wine is the Catalyst function that turns Grape juice into an Alcoholic beverage. Winemaking, or vinification, is the production of Wine, starting with selection of the Grapes and ending with bottling the finished wine Grape juice is a Juice obtained from crushing Grapes The juice is often fermented and made into Wine, Brandy, or Vinegar MUST may refer to Militära underrättelse- och säkerhetstjänsten, the Swedish Military Intelligence and Security Service Misr University Yeast is normally already invisibly present on the grapes. The fermentation can be done with this endogenous (or wild) yeast;[20] however, this may give unpredictable results depending on the exact types of yeast species that are present. For this reason a pure yeast culture is generally added to the must, which rapidly predominates the fermentation as it proceeds. This represses the wild yeasts and ensures a reliable and predictable fermentation. [21] Most added wine yeasts are strains of Saccharomyces cerevisiae, however not all strains of the species are suitable. Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times [21] Different S. cerevisiae yeast strains have differing physiological and fermentative properties, therefore the actual strain of yeast selected can have a direct impact on the finished wine. [22] Significant research has been undertaken into the development of novel wine yeast strains that produce atypical flavour profiles or increased complexity in wines. [23][24]

The growth of some yeasts such as Zygosaccharomyces and Brettanomyces in wine can result in wine faults and subsequent spoilage. Zygosaccharomyces is a Genus of Yeast in the family Saccharomycetaceae. Brettanomyces is a non-spore forming genus of Yeast in the family Saccharomycetaceae, and is often colloquially referred to as " A wine fault or defect is an unpleasant characteristic of a Wine often resulting from poor Winemaking practices [25] Brettanomyces produces an array of metabolites when growing in wine, some of which are volatile phenolic compounds. Brettanomyces is a non-spore forming genus of Yeast in the family Saccharomycetaceae, and is often colloquially referred to as " Metabolomics is the "systematic study of the unique chemical fingerprints that specific cellular processes leave behind" - specifically the study of their small-molecule metabolite Phenol, is a toxic colourless Crystalline Solid with a sweet tarry odor commonly referred to as a "hospital smell" Together these compounds are often referred to as "Brettanomyces character", and are often described as antiseptic or "barnyard" type aromas. Antiseptics (from Greek αντί - anti, '"against" + σηπτικός - septikos, "putrefactive" are antimicrobial Brettanomyces is a significant contributor to wine faults within the wine industry. A wine fault or defect is an unpleasant characteristic of a Wine often resulting from poor Winemaking practices [26]

Baking

Main article: Baker's yeast


Yeast, most commonly Saccharomyces cerevisiae, is used in baking as a leavening agent, where it converts the fermentable sugars present in the dough into carbon dioxide. Baker's yeast is the common name for the strains of Yeast commonly used as a Leavening agent in Baking Bread and related products where it converts Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times Baking is the technique of prolonged Cooking of Food by dry heat acting by conduction, and not by radiation, normally in an Oven, A leavening agent (sometimes called just leavening or leaven) is a substance used in Doughs and batters that causes a foaming action intended Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. Dough is a paste made out of any Cereals (grains or leguminous crops by mixing the Flour with a small amount of Water. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single This causes the dough to expand or rise as the carbon dioxide forms pockets or bubbles. Soda bubbles macrojpg|right|thumb|Bubbles of Gas in a Soft drink]] A bubble is a globule of one substance in another usually Gas in a Liquid When the dough is baked it "sets" and the pockets remain, giving the baked product a soft and spongy texture. The use of potatoes, water from potato boiling, eggs, or sugar in a bread dough accelerates the growth of yeasts. The potato is a Starchy Tuberous crop Vegetable from the perennial Solanum tuberosum of the Solanaceae An egg is a round or oval body laid by the female of many animals consisting of an Ovum surrounded by layers of Membranes and an outer casing which acts to nourish Sugar is a class of edible Crystalline substances mainly Sucrose, Lactose, and Fructose. Salt and fats such as butter slow down yeast growth. For sodium chloride in the diet see Salt. Sodium chloride, also known as common salt, table salt, or Halite, is a Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water Butter is a Dairy product made by churning fresh or fermented Cream or Milk. The majority of the yeast used in baking is of the same species common in alcoholic fermentation. Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions Additionally, Saccharomyces exiguus (also known as S. minor) is a wild yeast found on plants, fruits, and grains that is occasionally used for baking. Sugar and vinegar are the best conditions for yeast to ferment. In bread making the yeast respires aerobically at first producing carbon dioxide and water. When the oxygen is used up anaerobic respiration is used producing ethanol as a waste product however this is evaporated off during the baking process

A block of fresh yeast.
A block of fresh yeast.

It is not known when yeast was first used to bake bread. The first records that show this use came from Ancient Egypt. [27] Researchers speculate that a mixture of flour meal and water was left longer than usual on a warm day and the yeasts that occur in natural contaminants of the flour caused it to ferment before baking. The resulting bread would have been lighter and more tasty than the normal flat, hard cake.

Active dried yeast, a granulated form in which yeast is commercially sold.
Active dried yeast, a granulated form in which yeast is commercially sold.

Today there are several retailers of baker's yeast; one of the best-known is Fleischmann’s Yeast, which was developed in 1868. During World War II Fleischmann's developed a granulated active dry yeast, which did not require refrigeration and had a longer shelf life than fresh yeast. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including The company created yeast that would rise twice as fast, cutting down on baking time. Baker's yeast is also sold as a fresh yeast compressed into a square "cake". This form perishes quickly, and must be used soon after production in order to maintain viability. A weak solution of water and sugar can be used to determine if yeast is expired. Water ( H2[[oxygen O]] H OH) is the most abundant Molecule on Earth 's surface composing of about 70% of the Earth's surface as When dissolved in the solution, active yeast will foam and bubble as it ferments the sugar into ethanol and carbon dioxide. Some recipes refer to this as proofing the yeast as it gives proof of the viability of the yeast before the other ingredients are added. When using a sourdough starter, flour and water are added instead of sugar and this is referred to as proofing the sponge.

When yeast is used for making bread, it is mixed with flour, salt, and warm water (or milk). The dough is kneaded until it is smooth, and then left to rise, sometimes until it has doubled in size. Some bread doughs are knocked back after one rising and left to rise again. A longer rising time gives a better flavour, but the yeast can fail to raise the bread in the final stages if it is left for too long initially. The dough is then shaped into loaves, left to rise until it is the correct size, and then baked. Dried yeast is usually specified for use in a bread machine, however a (wet) sourdough starter can also work.

Bioremediation

Some yeasts can find potential application in the field of bioremediation. Bioremediation can be defined as any process that uses Microorganisms Fungi, green plants or their Enzymes to return the natural environment altered One such yeast Yarrowia lipolytica is known to degrade palm oil mill effluent,[28] TNT (an explosive material),[29] and other hydrocarbons such as alkanes, fatty acids, fats and oils. Palm oil is an edible plant oil derived from the Fruit of the Arecaceae Elaeis Oil palm. Effluent is an outflowing of water from a natural body of water or from a man-made structure Trinitrotoluene ( TNT) is a Chemical compound with the formula C6H2(NO23CH3 In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. Alkanes, also known as Paraffins are Chemical compounds that consist only of the elements Carbon (C and Hydrogen (H (i In Chemistry, especially Biochemistry, a fatty acid is a Carboxylic acid often with a long unbranched Aliphatic tail ( chain) which Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water An oil is a substance that is in a viscous Liquid state ( "oily") at ambient temperatures or slightly warmer and is [30]

Industrial ethanol production

The ability of yeast to convert sugar into ethanol has been harnessed by the biotechnology industry, which has various uses including ethanol fuel. Biotechnology is Technology based on Biology, especially when used in Agriculture, Food science, and Medicine. Ethanol fuel is Ethanol (ethyl alcohol the same type of Alcohol found in Alcoholic beverages. The process starts by milling a feedstock, such as sugar cane, sweetcorn, or cheap cereal grains, and then adding dilute sulfuric acid, or fungal alpha amylase enzymes, to break down the starches into complex sugars. Sugarcane ( Saccharum) is a genus of 6 to 37 species (depending on taxonomic interpretation of tall perennial grasses (family Poaceae tribe Andropogoneae Sweet corn ( Zea mays var rugosa) also called indian corn, sweetcorn, sugar corn, pole corn, or simply corn Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. Amylase is an Enzyme that breaks Starch down into Sugar. Amylase is present in human Saliva, where it begins the chemical process A gluco amylase is then added to break the complex sugars down into simple sugars. After this, yeasts are added to convert the simple sugars to ethanol, which is then distilled off to obtain ethanol up to 96% in concentration. Distillation is a method of separating Mixtures based on differences in their volatilities in a boiling liquid mixture [31]

Saccharomyces yeasts have been genetically engineered to ferment xylose, one of the major fermentable sugars present in cellulosic biomasses, such as agriculture residues, paper wastes, and wood chips. Genetic engineering, Recombinant DNA technology, genetic modification/manipulation (GM and gene splicing are terms that apply to the direct Xylose or wood sugar is an Aldopentose &mdash a Monosaccharide containing five Carbon Atoms and including an Aldehyde Functional Cellulose is an Organic compound with the formula, a Polysaccharide consisting of a linear chain of several hundred to over ten thousand β(1→4 [32] Such a development means that ethanol can be efficiently produced from more inexpensive feedstocks, making cellulosic ethanol fuel a more competitively priced alternative to gasoline fuels. Cellulosic ethanol also know by the name Ceetol, is a Biofuel produced from wood grasses or the non-edible parts of plants [33]

Kombucha

A Kombucha culture fermenting in a jar
A Kombucha culture fermenting in a jar

Yeast in symbiosis with acetic acid bacteria is used in the preparation of Kombucha, a fermented sweetened tea. Kombucha is the Western name for sweetened tea or Tisane that has been fermented using a macroscopic solid mass of microorganisms called a "kombucha colony" This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek Acetic acid bacteria are bacteria that derive their energy from the Oxidation of Ethanol to Acetic acid during respiration. Kombucha is the Western name for sweetened tea or Tisane that has been fermented using a macroscopic solid mass of microorganisms called a "kombucha colony" Tea refers to the cured agricultural product of the leaves leaf buds and internodes of Camellia sinensis, which have been prepared and cured for the market Species of yeast found in the tea can vary, and may include: Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe, Torulaspora delbrueckii and Zygosaccharomyces bailii. Brettanomyces bruxellensis (the Anamorph of Dekkera bruxellensis) is a Yeast native to the Senne valley near Brussels, Candida stellata is a species of Yeast of the genus Candida. In the 1978 work of Yarrow & Meyer the yeast was reclassified to its current name Schizosaccharomyces pombe, also called "fission yeast" is a Species of Yeast. Torulaspora delbrueckii is a yeast species which is also known as Saccharomyces delbrueckii or Saccharomyces rosei ( Anamorph Zygosaccharomyces bailii is the Type species for the genus Zygosaccharomyces. [34]

Nutritional supplements

Yeast is used in nutritional supplements popular with vegans and the health conscious, where it is often referred to as "nutritional yeast". It is a deactivated yeast, usually Saccharomyces cerevisiae. Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times It is an excellent source of protein and vitamins, especially the B-complex vitamins, whose functions are related to metabolism as well as other minerals and cofactors required for growth. The B vitamins are eight water-soluble Vitamins that play important roles in cell Metabolism. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific It is also naturally low in fat and sodium. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Some brands of nutritional yeast, though not all, are fortified with vitamin B12, which is produced separately from bacteria. Nutritional yeast, similar to Brewer's yeast, is a nutritional supplement popular with Vegans and the health conscious who use it as an ingredient Cyanocobalamin is an especially common Vitamer of the B-12 vitamin family. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Nutritional yeast, though it has a similar appearance to brewer's yeast, is very different and has a very different taste.

Nutritional yeast has a nutty, cheesy, creamy flavor which makes it popular as an ingredient in cheese substitutes. Cheese is a Food made from Milk, usually the milk of cows, Buffalo, Goats or sheep, by coagulation. It is often used by vegans in place of parmesan cheese. Parmigiano-Reggiano is a hard fat Granular cheese, cooked but not pressed named after the producing areas of Parma, Reggio Emilia, Modena, Another popular use is as a topping for popcorn. Popcorn or popping corn is a type of corn which explodes from the kernel and puffs up when heated Some movie theaters are beginning to offer it along with salt or cayenne pepper as a popcorn condiment. It comes in the form of flakes, or as a yellow powder similar in texture to cornmeal, and can be found in the bulk aisle of most natural food stores. In Australia it is sometimes sold as "savory yeast flakes". Though "nutritional yeast" usually refers to commercial products, inadequately fed prisoners have used "home-grown" yeast to prevent vitamin deficiency. [35]

Probiotics

Some probiotic supplements use the yeast Saccharomyces boulardii to maintain and restore the natural flora in the large and small gastrointestinal tract. Probiotics are Dietary supplements containing potentially beneficial Bacteria or Yeasts According to the currently adopted definition by FAO / Saccharomyces boulardii is a tropical strain of Yeast first isolated from Lychee and Mangosteen fruit in 1923 by French scientist Henri S. boulardii has been shown to reduce the symptoms of acute diarrhea in children,[36][37] prevent reinfection of Clostridium difficile,[38] reduce bowel movements in diarrhea predominant IBS patients,[39] and reduce the incidence of antibiotic,[40] traveler's,[41] and HIV/AIDS[42] associated diarrheas. In Medicine, diarrhea, also spelled diarrhoea (see spelling differences) is frequent loose or liquid Bowel movements Acute diarrhea Clostridium difficile (pronounced /klɒsˈtrɪdiəm dɪˈfɪsɪli/ also known as CDF/cdf' or 'C In Gastroenterology, irritable bowel syndrome ( IBS) is a Functional bowel disorder characterized by mild to severe Abdominal pain, discomfort Clostridium difficile Pseudomembranous colitis is an infection of the colon often but not always caused by the Bacterium Clostridium difficile Traveler's diarrhea (in American English or traveller's diarrhœa (in British English abbreviated to TD, is the most common illness affecting travelers

Science

Diagram showing a yeast cell
Diagram showing a yeast cell

Several yeasts, particularly Saccharomyces cerevisiae, have been widely used in genetics and cell biology. Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times Genetics (from Ancient Greek grc-Latn genetikos, “genitive” and that from grc-Latn genesis, “origin” a discipline of Biology, is See also List of basic cell biology topics. Cell biology (also called cellular biology or formerly cytology, from the This is largely because the cell cycle in a yeast cell is very similar to the cell cycle in humans, and therefore the basic cellular mechanics of DNA replication, recombination, cell division and metabolism are comparable. The cell cycle, or cell-division cycle, is the series of events that take place in a eukaryotic cell leading to its replication Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus DNA replication is the process of copying a double-stranded DNA molecule to form two double-stranded molecules Cell division is a process by which a cell, called the parent cell divides into two or more cells called daughter cells. Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. [9] Also many proteins important in human biology were first discovered by studying their homologs in yeast; these proteins include cell cycle proteins, signaling proteins, and protein-processing enzymes. In Evolutionary biology, homology has come to mean any similarity between characters that is due to their shared ancestry. The cell cycle, or cell-division cycle, is the series of events that take place in a eukaryotic cell leading to its replication Cell signaling is part of a Complex system of Communication that governs basic cellular activities and coordinates cell actions

On 24 April 1996 S. Events 1479 BC - Thutmose III ascends to the throne of Egypt, although power effectively shifts to Hatshepsut (according to Year 1996 ( MCMXCVI) was a Leap year starting on Monday (link will display full 1996 Gregorian calendar) cerevisiae was announced to be the first eukaryote to have its genome, consisting of 12 million base pairs, fully sequenced as part of the Genome project. In classical genetics the genome of a Diploid Organism including Eukarya refers to a full set of chromosomes or genes in a Gamete, thereby In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called Genome projects are Scientific endeavours that ultimately aim to determine the complete Genome sequence of an Organism (be it an Animal, a [43] At the time it was the most complex organism to have its full genome sequenced and took 7 years and the involvement of more than 100 laboratories to accomplish. [44] The second yeast species to have its genome sequenced was Schizosaccharomyces pombe, which was completed in 2002. Schizosaccharomyces pombe, also called "fission yeast" is a Species of Yeast. [45] It was the 6th eukaryotic genome sequenced and consists of 13. 8 million base pairs.

Yeast extract

Main article: Yeast extract
Marmite and Vegemite have a distinctive dark colour
Marmite and Vegemite have a distinctive dark colour
Vegemite and Marmite, products made from yeast extract
Vegemite and Marmite, products made from yeast extract

Yeast extract is the common name for various forms of processed yeast products that are used as food additives or flavours. Yeast extract is the common name for various forms of processed Yeast products that are used as food additives or flavourings Vegemite ( is a dark brown savoury food paste made from Yeast extract, used mainly as a spread on Sandwiches Toast and cracker biscuits Marmite (/ˈmɑːmaɪt/ is the name given to two similar food spreads a British version produced in the United Kingdom and South Africa and the other in New Yeast extract is the common name for various forms of processed Yeast products that are used as food additives or flavourings Food additives are substances added to food to preserve flavour or improve its taste and appearance Flavor or flavour is the sensory impression of a Food or other substance, and is determined They are often used in the same way that monosodium glutamate (MSG) is used, and like MSG, often contain free glutamic acids. Monosodium glutamate, also known as sodium glutamate and MSG, is a Sodium salt of the non-essential Amino acid Glutamic acid Glutamic acid (abbreviated as Glu or E) is one of the 20 Alpha Amino acids It is not among the human Essential amino acids Its 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. Vegemite ( is a dark brown savoury food paste made from Yeast extract, used mainly as a spread on Sandwiches Toast and cracker biscuits Marmite (/ˈmɑːmaɪt/ is the name given to two similar food spreads a British version produced in the United Kingdom and South Africa and the other in New This triggers autolysis, where the yeast's digestive enzymes break their own proteins down into simpler compounds, a process of self-destruction. In biology autolysis may refer 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 Digestion is the breaking down of chemicals in the body into a form that can be absorbed Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl The dying yeast cells are then heated to complete their breakdown, after which the husks (yeast with thick cell walls which would give poor texture) are separated. Yeast autolysates are used in Vegemite and Promite (Australia); Marmite, Bovril and Oxo (the United Kingdom, Republic of Ireland and South Africa); and Cenovis (Switzerland). Vegemite ( is a dark brown savoury food paste made from Yeast extract, used mainly as a spread on Sandwiches Toast and cracker biscuits Promite (ˈproʊmaɪt 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 For a topic outline on this subject see List of basic Australia topics. Marmite (/ˈmɑːmaɪt/ is the name given to two similar food spreads a British version produced in the United Kingdom and South Africa and the other in New Bovril is the trademarked name of a thick salty Beef extract sold in a distinctive bulbous jar Oxo is a brand of various food products consisting of stock cubes, herbs and spices dried gravy and Yeast extract. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Ireland ( Irish: Éire, ˈeːrʲə is a country in north-western Europe. The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa Cenovis is a product based on Yeast extract similar to Vegemite and Marmite, rich in vitamin B1. Switzerland (English pronunciation; Schweiz Swiss German: Schwyz or Schwiiz Suisse Svizzera Svizra officially the Swiss Confederation

Pathogenic yeasts

A photomicrograph of Candida albicans showing hyphal outgrowth and other morphological characteristics.
A photomicrograph of Candida albicans showing hyphal outgrowth and other morphological characteristics. A micrograph, microphotograph or photomicrograph is a Photograph or similar image taken through a Microscope or similar device to show Candida albicans is a Diploid Fungus (a form of Yeast) which is capable of mating but not of Meiosis, and a causal agent of

Some species of yeast are opportunistic pathogens where they can cause infection in people with compromised immune systems. An opportunistic infection is an infection caused by Pathogens that usually do not cause disease in a healthy Immune system. An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor

Cryptococcus neoformans is a significant pathogen of immunocompromised people causing the disease termed Cryptococcosis. Cryptococcus neoformans is an encapsulated yeast-like Fungus that can live in both Plants and Animals This species also known by its Cryptococcosis is a serious and potentially fatal Fungal disease caused by members of the Cryptococcus neoformans species complex comprising the two species This disease occurs in about 7–9% of AIDS patients in the USA, and a slightly smaller percentage (3–6%) in western Europe. [46] The cells of the yeast are surrounded by a rigid polysaccharide capsule, which helps to prevent them from being recognised and engulfed by white blood cells in the human body. Polysaccharides are relatively complex Carbohydrates They are Polymers made up of many Monosaccharides joined together by Glycosidic bonds

Yeasts of the Candida genus are another group of opportunistic pathogens which causes oral and vaginal infections in humans, known as Candidiasis. Candida is a Genus of Yeasts Many species of this genus are Endosymbionts The vagina (from Latin, literally " Sheath " or " Scabbard " is a fibromuscular tubular tract leading from the Uterus An infection is the detrimental Colonization of a host Organism by a foreign Species. Candidiasis, commonly called yeast infection or thrush, is a Fungal infection (mycosis of any of the Candida species of which Candida is commonly found as a commensal yeast in the mucus membranes of humans and other warm-blooded animals. In Ecology, commensalism is a kind of symbiotic relationship between two organisms where one benefits and the other is not significantly harmed or helped (like a bird The mucous membranes (or mucosae; singular mucosa) are linings of mostly endodermal origin covered in Epithelium, which are involved in However, sometimes these same strains can become pathogenic. Here the yeast cells sprout a hyphal outgrowth, which locally penetrates the mucosal membrane, causing irritation and shedding of the tissues. A hypha (plural hyphae) is a long branching filamentous cell of a Fungus, and also of unrelated Actinobacteria. The mucous membranes (or mucosae; singular mucosa) are linings of mostly endodermal origin covered in Epithelium, which are involved in [46] The pathogenic yeasts of candidiasis in probable descending order of virulence for humans are: C. albicans, C. tropicalis, C. stellatoidea, C. glabrata, C. krusei, C. parapsilosis, C. guilliermondii, C. viswanathii, C. lusitaniae and Rhodotorula mucilaginosa. Candida albicans is a Diploid Fungus (a form of Yeast) which is capable of mating but not of Meiosis, and a causal agent of Candida tropicalis is a species of Yeast in the genus Candida. Candida albicans is a Diploid Fungus (a form of Yeast) which is capable of mating but not of Meiosis, and a causal agent of Candida glabrata is a Haploid Yeast of the genus Candida, previously known as Torulopsis glabrata. Candida krusei is a budding Yeast (a species of Fungus) involved in Chocolate production Candida paraposis is a fungal species of the Yeast family that has become a significant cause of Sepsis and of wound and tissue infections Pichia guilliermondii is a species of Yeast of the genus Pichia whose asexual or Anamorphic form is known as Candida guilliermondii Candida viswanathii is a species of Yeast in the genus Candida. Candida lusitaniae is a species of Yeast in the genus Candida. Rhodotorula is a pigmented Yeast, part of the Basidiomycota phylum easily identifiable by distinctive orange/red colonies when grown on SDA (Sabaroud's [47] Candida glabrata is the second most common Candida pathogen after C. Candida glabrata is a Haploid Yeast of the genus Candida, previously known as Torulopsis glabrata. albicans, causing infections of the urogenital tract, and of the bloodstream (Candidemia). In Anatomy, the genitourinary system is the Organ system of all the Reproductive organs and the Urinary system. This is an article about the rock music band "Circulatory System" Fungemia (also known as Candidemia, Candedemia, and Invasive Candidiasis) is the presence of fungi or Yeasts in the Blood [48]

Non-pathogenic yeast such as S. cerevisiae are also implicated in disease; anti saccharomyces cerevisiae antibodies (ASCA) have been found at relatively high frequencies in familial crohn's disease and at higher frequencies in other forms of colitis. Anti- Saccharomyces cerevisiae antibodies ( ASCA) along with perinuclear antineutrophil cytoplasmic antibodies (pANCA are among the two most useful and often discriminating Crohn's disease is a Disease of the Digestive system which may affect any part of the Gastrointestinal tract from Mouth to Anus Colitis is a chronic digestive disease characterized by Inflammation of the colon. [49]

Food spoilage

Yeasts are able to grow in foods with a low pH, (5. 0 or lower) and in the presence of sugars, organic acids and other easily metabolized carbon sources. [50] During their growth, yeasts metabolize some food components and produce metabolic end products. This causes the physical, chemical, and sensory properties of a food to change, and the food is spoiled. [51] The growth of yeast within food products is often seen on their surface, as in cheeses or meats, or by the fermentation of sugars in beverages, such as juices, and semi-liquid products, such as syrups and jams. Cheese is a Food made from Milk, usually the milk of cows, Buffalo, Goats or sheep, by coagulation. In modern English usage meat most often refers to Animal tissue used as food mostly Skeletal muscle and associated Fat, but it may also refer JUICE is a widely used non-commercial Software package for editing and analysing phytosociological data In Cooking, a syrup (from Arabic' ar شراب sharab, beverage via Latin siropus) is a thick Viscous Liquid [50] The yeast of the Zygosaccharomyces genus have had a long history as a spoilage yeast within the food industry. Zygosaccharomyces is a Genus of Yeast in the family Saccharomycetaceae. This is mainly due to the fact that these species can grow in the presence of high sucrose, ethanol, acetic acid, sorbic acid, benzoic acid, and sulfur dioxide concentrations,[52] representing some of the commonly used food preservation methods. Solubility of Pure SucroseTemperature(Cg Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste Sometimes confused with Ascorbic acid, Vitamin C. Sorbic acid, or 24-hexadienoic acid is a natural Organic compound Benzoic acid, C7H6O2 (or C6H5COOH is a colorless crystalline solid and the simplest Aromatic Carboxylic acid Food preservation is the process of treating and handling Food in a way that preserves its edibility and nutrition value Methylene Blue is used to test for the presence of live yeast cells. Methylene blue is a heterocyclic aromatic Chemical compound with Molecular formula: C 16 H 18 Cl[[nitrogen

See also

References

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External links

Dictionary

yeast

-noun

  1. A type of single-celled fungus.
  2. An often humid, yellowish froth, made of these fungi, used in medicine, in baking and in brewing beer.
  3. A compressed cake or dried granules of this substance used for mixing with flour to make bread dough rise.
  4. (figuratively) A frothy foam on sea waves.

-verb

  1. (African American Vernacular, slang) To exaggerate<ref>http://www.probertencyclopaedia.com/cgi-bin/res.pl?keyword=Yeasting&offset=0</ref>
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