Second messenger system
Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers. Second messengers trigger physiological changes such as proliferation, migration and apoptosis, they are one of the triggers of intracellular signal transduction cascades. Examples of second messenger molecules include cyclic AMP, cyclic GMP, inositol trisphosphate and calcium. First messengers are extracellular factors hormones or neurotransmitters, such as epinephrine, growth hormone, serotonin; because peptide hormones and neurotransmitters are biochemically hydrophilic molecules, these first messengers may not physically cross the phospholipid bilayer to initiate changes within the cell directly—unlike steroid hormones, which do. This functional limitation necessitates the cell to devise signal transduction mechanisms to transduce first messenger into second messengers, so that the extracellular signal may be propagated intracellularly.
An important feature of the second messenger signaling system is that second messengers may be coupled downstream to multi-cyclic kinase cascades to amplify the strength of the original first messenger signal. For example, RasGTP signals link with the Mitogen Activated Protein Kinase cascade to amplify the allosteric activation of proliferative transcription factors such as Myc and CREB. Earl Wilbur Sutherland, Jr. discovered second messengers, for which he won the 1971 Nobel Prize in Physiology or Medicine. Sutherland saw that epinephrine would stimulate the liver to convert glycogen to glucose in liver cells, but epinephrine alone would not convert glycogen to glucose, he found that epinephrine had to trigger a second messenger, cyclic AMP, for the liver to convert glycogen to glucose. The mechanisms were worked out in detail by Martin Rodbell and Alfred G. Gilman, who won the 1994 Nobel Prize. Secondary messenger systems can be synthesized and activated by enzymes, for example, the cyclases that synthesize cyclic nucleotides, or by opening of ion channels to allow influx of metal ions, for example Ca2+ signaling.
These small molecules bind and activate protein kinases, ion channels, other proteins, thus continuing the signaling cascade. There are three basic types of secondary messenger molecules: Hydrophobic molecules: water-insoluble molecules such as diacylglycerol, phosphatidylinositols, which are membrane-associated and diffuse from the plasma membrane into the intermembrane space where they can reach and regulate membrane-associated effector proteins Hydrophilic molecules: water-soluble molecules, such as cAMP, cGMP, IP3, Ca2+, that are located within the cytosol Gases: nitric oxide, carbon monoxide and hydrogen sulfide which can diffuse both through cytosol and across cellular membranes; these intracellular messengers have some properties in common: They can be synthesized/released and broken down again in specific reactions by enzymes or ion channels. Some can be stored in special organelles and released when needed, their production/release and destruction can be localized, enabling the cell to limit space and time of signal activity.
There are several different secondary messenger systems, but they all are quite similar in overall mechanism, although the substances involved and overall effects can vary. In most cases, a ligand binds to a membrane-spanning receptor protein molecule; the binding of a ligand to the receptor causes a conformation change in the receptor. This conformation change can affect the activity of the receptor and result in the production of active second messengers. In the case of G protein-coupled receptors, the conformation change exposes a binding site for a G-protein; the G-protein is bound to the inner membrane of the cell and consists of three subunits: alpha and gamma. The G-protein is known as the "transducer." When the G-protein binds with the receptor, it becomes able to exchange a GDP molecule on its alpha subunit for a GTP molecule. Once this exchange takes place, the alpha subunit of the G-protein transducer breaks free from the beta and gamma subunits, all parts remaining membrane-bound; the alpha subunit, now free to move along the inner membrane contacts another membrane-bound protein - the "primary effector."
The primary effector has an action, which creates a signal that can diffuse within the cell. This signal is called the "second messenger." The secondary messenger may activate a "secondary effector" whose effects depend on the particular secondary messenger system. Calcium ions are one type of second messengers and are responsible for many important physiological functions including muscle contraction and neurotransmitter release; the ions are bound or stored in intracellular components and can be released during signal transduction. The enzyme phospholipase C produces diacylglycerol and inositol trisphosphate, which increases calcium ion permeability into the membrane. Active G-protein open up calcium channels to let calcium ions enter the plasma membrane; the other product of phospholipase C, activates protein kinase C, which assists in the activation of cAMP. IP3, DAG, Ca2+ are second messengers in the phosphoinositol pathway; the pathway begins with the binding of ex
Cottonseed oil is a cooking oil extracted from the seeds of cotton plants of various species Gossypium hirsutum and Gossypium herbaceum, that are grown for cotton fiber, animal feed, oil. Cotton seed has a similar structure to other oilseeds such as sunflower seed, having an oil-bearing kernel surrounded by a hard outer hull. Cottonseed oil is used for salad oil, salad dressing, similar products because of its flavor stability, its fatty acid profile consists of 70% unsaturated fatty acids, 26% saturated fatty acids. When it is hydrogenated, its profile is 94% saturated fat and 2% unsaturated fatty acids. According to the cottonseed oil industry, cottonseed oil does not need to be hydrogenated as much as other polyunsaturated oils to achieve similar results. Gossypol is a toxic, polyphenolic compound produced by cotton and other members of the order Malvaceae, such as okra; this occurring coloured compound is found in tiny glands in the seed, stem, tap root bark, root of the cotton plant. The adaptive function of the compound facilitates natural insect resistance.
The three key steps of refining and deodorization in producing finished oil act to eliminate the gossypol level. Ferric chloride is used to decolorize cotton seed oil. Once processed, cottonseed oil has a mild taste and appears clear with a light golden color, the amount of color depending on the amount of refining, it has a high smoke point as a frying medium. Density ranges from 0.917 g/cm3 to 0.933 g/cm3. Like other long-chain fatty acid oils, cottonseed oil has a smoke point of about 450 °F, is high in tocopherols, which contribute its stability, giving products that contain it a long shelf life, hence manufacturers' proclivity to use it in packaged goods; the by-product of cotton processing, cottonseed was considered worthless before the late 19th century. While cotton production expanded throughout the 17th, 18th, mid 19th centuries, a worthless stock of cottonseed grew. Although some of the seed was used for planting and animal feed, the majority was left to rot or was illegally dumped into rivers.
In the 1820s and 1830s Europe experienced fats and oils shortages due to rapid population expansion during the Industrial Revolution and the after-effects of the British blockade during the Napoleonic Wars. The increased demand for fats and oils, coupled with a decreasing supply caused prices to rise sharply. Many Europeans could not afford to buy the fats and oils they had used for cooking and for lighting. Many United States entrepreneurs tried to take advantage of the increasing European demand for oils and America’s large supply of cottonseed by crushing the seed for oil, but separating the seed hull from the seed meat proved difficult and most of these ventures failed within a few years. This problem was resolved in 1857, when William Fee invented a huller, which separated the tough hulls from the meats of cottonseed. With this new invention, cottonseed oil began to be used for illumination purposes in lamps to supplement expensive whale oil and lard, but by 1859, this use came to end. Cottonseed oil began to be used illegally to fortify animal fats and lards.
Meat packers secretly added cottonseed oil to the pure fats, but this practice was uncovered in 1884. Armour and Company, an American meatpacking and food processing company, sought to corner the lard market and realized that it had purchased more lard than the existing hog population could have produced. A congressional investigation followed, legislation was passed that required products fortified with cottonseed oil to be labeled as ‘‘lard compound.” Cottonseed oil was blended with olive oil. Once the practice was exposed, many countries put import tariffs on American olive oil and Italy banned the product in 1883. Both of these regulatory schemes depressed cottonseed oil sales and exports, once again creating an oversupply of cottonseed oil, which decreased its value, it was cottonseed's depressed value that led a newly formed Gamble to utilize its oil. The Panic of 1837 caused the two brothers-in-law to merge their candlestick and soap manufacturing businesses in an effort to minimize costs and weather the bear market.
Looking for a replacement for expensive animal fats in production, the brothers settled on cottonseed oil. Procter & Gamble cornered the cottonseed oil market to circumvent the meat packer's monopoly on the price, but as electricity emerged, the demand for candles decreased. Procter and Gamble found an edible use for cottonseed oil. Through patented technology, the brothers were able to hydrogenate cottonseed oil and develop a substance that resembled lard. In 1911, Procter & Gamble launched an aggressive marketing campaign to publicize its new product, Crisco, a vegetable shortening that could be used in place of lard. Crisco placed ads in major newspapers advertising that the product was "easier on digestion...a healthier alternative to cooking with animal fats... and more economical than butter.” The company gave away free cookbooks, with every recipe calling for Crisco. By the 1920s the company developed cookbooks for specific ethnicities in their native tongues. Additionally, Crisco starting airing radio cooking programs.
In 1899 David Wesson, a food chemist, developed deodorized cottonseed oil, Wesson cooking oil. Wesson Oil was marketed and became quite popular too. Over the next 30 years cottonseed oil became the pre-eminent oil in the United S
Glycerol is a simple polyol compound. It is a colorless, viscous liquid, sweet-tasting and non-toxic; the glycerol backbone is found in many lipids which are known as glycerides. It is used in the food industry as a sweetener and humectant in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. Although achiral, glycerol is prochiral with respect to reactions of one of the two primary alcohols. Thus, in substituted derivatives, the stereospecific numbering labels each carbon as either sn-1, sn-2, or sn-3. Glycerol is obtained from plant and animal sources where it occurs in triglycerides, esters of glycerol with long-chain carboxylic acids; the hydrolysis, saponification, or transesterification of these triglycerides produces glycerol as well as the fatty acid derivative: Triglycerides can be saponified with sodium hydroxide to give glycerol and fatty sodium salt or soap. Typical plant sources include soybeans or palm.
Animal-derived tallow is another source. 950,000 tons per year are produced in the United States and Europe. The EU directive 2003/30/EC set a requirement that 5.75% of petroleum fuels are to be replaced with biofuel sources across all member states by 2010. It was projected in 2006 that by the year 2020, production would be six times more than demand, creating an excess of glycerol. Glycerol from triglycerides is produced on a large scale, but the crude product is of variable quality, with a low selling price of as low as 2-5 U. S. cents per kilogram in 2011. It can be purified, but the process is expensive; some glycerol is burned for energy, but its heat value is low. Crude glycerol from the hydrolysis of triglycerides can be purified by treatment with activated carbon to remove organic impurities, alkali to remove unreacted glycerol esters, ion exchange to remove salts. High purity glycerol is obtained by multi-step distillation. Although not cost-effective, glycerol can be produced by various routes from propylene.
The epichlorohydrin process is the most important. This epichlorohydrin is hydrolyzed to give glycerol. Chlorine-free processes from propylene include the synthesis of glycerol from acrolein and propylene oxide; because of the large-scale production of biodiesel from fats, where glycerol is a waste product, the market for glycerol is depressed. Thus, synthetic processes are not economical. Owing to oversupply, efforts are being made to convert glycerol to synthetic precursors, such as acrolein and epichlorohydrin. (See the Chemical intermediate section of this article. In food and beverages, glycerol serves as a humectant and sweetener, may help preserve foods, it is used as filler in commercially prepared low-fat foods, as a thickening agent in liqueurs. Glycerol and water are used to preserve certain types of plant leaves; as a sugar substitute, it has 27 kilocalories per teaspoon and is 60% as sweet as sucrose. It does not feed the bacteria that form plaques and cause dental cavities; as a food additive, glycerol is labeled as E number E422.
It is added to icing to prevent it from setting too hard. As used in foods, glycerol is categorized by the Academy of Nutrition and Dietetics as a carbohydrate; the U. S. Food and Drug Administration carbohydrate designation includes all caloric macronutrients excluding protein and fat. Glycerol has a caloric density similar to table sugar, but a lower glycemic index and different metabolic pathway within the body, so some dietary advocates accept glycerol as a sweetener compatible with low-carbohydrate diets, it is recommended as an additive when using polyol sweeteners such as erythritol and xylitol which have a cooling effect, due to its heating effect in the mouth, if the cooling effect is not wanted. Glycerol is used in medical and personal care preparations as a means of improving smoothness, providing lubrication, as a humectant. Ichthyosis and xerosis have been relieved by the topical use glycerin, it is found in allergen immunotherapies, cough syrups and expectorants, mouthwashes, skin care products, shaving cream, hair care products and water-based personal lubricants.
In solid dosage forms like tablets, glycerol is used as a tablet holding agent. For human consumption, glycerol is classified by the U. S. FDA among the sugar alcohols as a caloric macronutrient. Glycerol is used in blood banking to preserve red blood cells prior to freezing. Glycerol is a component of glycerin soap. Essential oils are added for fragrance; this kind of soap is used by people with sensitive irritated skin because it prevents skin dryness with its moisturizing properties. It draws moisture up through skin layers and slows or prevents excessive drying and evaporation. Taken rectally, glycerol functions as a laxative by irritating the anal mucosa and inducing a hyperosmotic effect, it may be administered undiluted either as a suppository or as a small-volume enema. Alternatively, it may be administered in a dilute solution, e.g. 5%, as a high volume enema. Taken orally, glycerol can cause a rapid, temporary decrease in the internal pressure of the eye; this can be useful for the initial emergency treatment of elevated eye pressure.
Phosphoinositide 3-kinases called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, differentiation, motility and intracellular trafficking, which in turn are involved in cancer. PI3Ks are a family of related intracellular signal transducer enzymes capable of phosphorylating the 3 position hydroxyl group of the inositol ring of phosphatidylinositol; the pathway, with oncogene PIK3CA and tumor suppressor PTEN, is implicated in the sensitivity of cancer tumors to insulin and IGF1, in calorie restriction. The discovery of PI3Ks by Lewis Cantley and colleagues began with their identification of a unknown phosphoinositide kinase associated with the polyoma middle T protein, they observed unique substrate specificity and chromatographic properties of the products of the lipid kinase, leading to the discovery that this phosphoinositide kinase had the unprecedented ability to phosphorylate phosphoinositides on the 3' position of the inositol ring.
Subsequently and colleagues demonstrated that in vivo the enzyme prefers PtdInsP2 as a substrate, producing the novel phosphoinositide PtdInsP3 identified in neutrophils The PI3K family is divided into four different classes: Class I, Class II, Class III, Class IV. The classifications are based on primary structure, in vitro lipid substrate specificity. Class I PI3Ks catalyze the conversion of phosphatidylinositol -bisphosphate into phosphatidylinositol -trisphosphate in vivo. While in vitro, they have been shown to convert phosphatidylinositol into phosphatidylinositol 3-phosphate and phosphatidylinositol 4-phosphate into phosphatidylinositol -bisphosphate, these reactions are disfavoured in vivo; the PI3K is activated by tyrosine kinase receptors. Class I PI3Ks are heterodimeric molecules composed of a catalytic subunit. Class IA PI3Ks are composed of a heterodimer between a p110 catalytic subunit and a p85 regulatory subunit. There are five variants of the p85 regulatory subunit, designated p85α, p55α, p50α, p85β, p55γ.
There are three variants of the p110 catalytic subunit designated p110α, β, or δ catalytic subunit. The first three regulatory subunits are all splice variants of the same gene, the other two being expressed by other genes; the most expressed regulatory subunit is p85α. The first two p110 isoforms are expressed in all cells, but p110δ is expressed in leukocytes, it has been suggested that it evolved in parallel with the adaptive immune system; the regulatory p101 and catalytic p110γ subunits comprise the class IB PI3Ks and are encoded by a single gene each. The p85 subunits contain SH3 domains; the SH2 domains bind preferentially to phosphorylated tyrosine residues in the amino acid sequence context Y-X-X-M. Class II and III PI3Ks are differentiated from the Class I by their function; the distinct feature of Class II PI3Ks is the C-terminal C2 domain. This domain lacks critical Asp residues to coordinate binding of Ca2+, which suggests class II PI3Ks bind lipids in a Ca2+-independent manner. Class II comprises three catalytic isoforms, unlike Classes I and III, no regulatory proteins.
Class II catalyse the production of PIP from PI and PIP2 from PIP. PIP2 has, been shown to play a role in the invagination phase of clathrin-mediated endocytosis. C2α and C2β are expressed through the body. Class III PI3Ks produce only PIP from PI but are more similar to Class I in structure, as they exist as heterodimers of a catalytic and a regulatory subunits. Class III seems to be involved in the trafficking of proteins and vesicles. There is, evidence to show that they are able to contribute to the effectiveness of several process important to immune cells, not least phagocytosis. A group of more distantly related enzymes is sometimes referred to as class IV PI3Ks, it is composed of ataxia telangiectasia mutated, ataxia telangiectasia and Rad3 related, DNA-dependent protein kinase and mammalian target of rapamycin. They are protein serine/threonine kinases; the various 3-phosphorylated phosphoinositides that are produced by PI3Ks function in a mechanism by which an assorted group of signalling proteins, containing PX domains, pleckstrin homology domains, FYVE domains or other phosphoinositide-binding domains, are recruited to various cellular membranes.
PI3Ks have been linked to an extraordinarily diverse group of cellular functions, including cell growth, differentiation, motility and intracellular trafficking. Many of these functions relate to the ability of class I PI3Ks to activate protein kinase B as in the PI3K/AKT/mTOR pathway; the p110δ and p110γ isoforms regulate different aspects of immune responses. PI3Ks are a key component of the insulin signaling pathway. Hence there is great interest in the role of PI3K signaling in diabetes mellitus; the pleckstrin homology domain of AKT binds directly to PtdInsP3 and PtdInsP2, which are produced by activated PI3Ks. Since PtdIn
Fatty acid metabolism
Fatty acid metabolism consists of catabolic processes that generate energy, anabolic processes that create biologically important molecules. Fatty acids are a family of molecules classified within the lipid macronutrient class. One role of fatty acids in animal metabolism is energy production, captured in the form of adenosine triphosphate; when compared to other macronutrient classes, fatty acids yield the most ATP on an energy per gram basis, when they are oxidized to CO2 and water by beta oxidation and the citric acid cycle. Fatty acids are therefore the foremost storage form of fuel in most animals, to a lesser extent in plants. In addition, fatty acids are important components of the phospholipids that form the phospholipid bilayers out of which all the membranes of the cell are constructed. Fatty acids can be cleaved, or cleaved, from their chemical attachments in the cell membrane to form second messengers within the cell, local hormones in the immediate vicinity of the cell; the prostaglandins made from arachidonic acid stored in the cell membrane, are the most well known group of these local hormones.
Fatty acids are released, between meals, from the fat depots in adipose tissue, where they are stored as triglycerides, as follows: Lipolysis, the removal of the fatty acid chains from the glycerol to which they are bound in their storage form as triglycerides, is carried out by lipases. These lipases are activated by high epinephrine and glucagon levels in the blood, caused by declining blood glucose levels after meals, which lowers the insulin level in the blood. Once freed from glycerol, the free fatty acids enter the blood, which transports them, attached to plasma albumin, throughout the body. Long chain free fatty acids enter the metabolizing cells through specific transport proteins, such as the SLC27 family fatty acid transport protein. Red blood cells are therefore incapable of metabolizing fatty acids. Once inside the cell long-chain-fatty-acid—CoA ligase catalyzes the reaction between a fatty acid molecule with ATP to give a fatty acyl-adenylate, which reacts with free coenzyme A to give a fatty acyl-CoA molecule.
In order for the acyl-CoA to enter the mitochondrion the carnitine shuttle is used:Acyl-CoA is transferred to the hydroxyl group of carnitine by carnitine palmitoyltransferase I, located on the cytosolic faces of the outer and inner mitochondrial membranes. Acyl-carnitine is shuttled inside by a carnitine-acylcarnitine translocase, as a carnitine is shuttled outside. Acyl-carnitine is converted back to acyl-CoA by carnitine palmitoyltransferase II, located on the interior face of the inner mitochondrial membrane; the liberated carnitine is shuttled back to the cytosol. Beta oxidation, in the mitochondrial matrix cuts the long carbon chains of the fatty acids into a series of two-carbon units, combined with co-enzyme A, form molecules of acetyl CoA, which condense with oxaloacetate to form citrate at the "beginning" of the citric acid cycle, it is convenient to think of this reaction as marking the "starting point" of the cycle, as this is when fuel - acetyl-CoA - is added to the cycle, which will be dissipated as CO2 and H2O with the release of a substantial quantity of energy captured in the form of ATP, during the course of each turn of the cycle.
The steps in beta oxidation are as follows:Dehydrogenation by acyl-CoA dehydrogenase, yielding 1 FADH2 Hydration by enoyl-CoA hydratase Dehydrogenation by 3-hydroxyacyl-CoA dehydrogenase, yielding 1 NADH + H+ Cleavage by thiolase, yielding 1 acetyl-CoA and a fatty acid that has now been shortened by 2 carbons This beta oxidation reaction is repeated until the fatty acid has been reduced to acetyl-CoA or, in, the case of fatty acids with odd numbers of carbon atoms, acetyl-CoA and 1 molecule of propionyl-CoA per molecule of fatty acid. Each beta oxidative cut of the acyl-CoA molecule yields 5 ATP molecules; the acetyl-CoA produced by beta oxidation enters the citric acid cycle in the mitochondrion by combining with oxaloacetate to form citrate. This results in the complete combustion of the acetyl-CoA to water; the energy released in this process is captured in the form of 1 GTP and 11 ATP molecules per acetyl-CoA molecule oxidized. This is the fate of acetyl-CoA wherever beta oxidation of fatty acids occurs, except under certain circumstances in the liver.
In the liver oxaloacetate can be wholly or diverted into the gluconeogenic pathway during fasting, starvation, a low carbohydrate diet, prolonged strenuous exercise, in uncontrolled type 1 diabetes mellitus. Under these circumstances oxaloacetate is hydrogenated to malate, removed from the mitochondrion to be converted into glucose in the cytoplasm of the liver cells, from where it is released into the blood. In
Monoglycerides are a class of glycerides which are composed of a molecule of glycerol linked to a fatty acid via an ester bond. As glycerol contains both primary and secondary alcohol groups two different types of monoglycerides may be formed. Monoglycerides are produced both industrially, they are present at low levels in some seed oils such as olive oil, rapeseed oil and cottonseed oil. They are biosynthesized by the enzymatic hydrolysis of triglycerides by lipoprotein lipase and the enzymatic hydrolysis of diglycerides by diacylglycerol lipase. Several monoglycerides are pharmacologically active. Industrial production is achieved by a glycerolysis reaction between triglycerides and glycerol; the commercial raw materials for the production of monoacylglycerols may be either vegetable or animal fats and oils. Monoglycerides are used as surfactants in the form of emulsifiers. Together with diglycerides, monoglycerides are added to commercial food products in small quantities as E471, which helps to prevent mixtures of oils and water from separating.
The values given in the nutritional labels for total fat, saturated fat, trans fat do not include those present in mono- and diglycerides as fats are defined as being triglycerides. They are often found in bakery products, ice cream, chewing gum, whipped toppings and confections. In bakery products, monoglycerides are useful in improving loaf volume and texture, as antistaling agents. Monoglycerides are used to enhance the physical stability towards creaming in milk beverages. Diglyceride Dietary sources of fatty acids, their digestion, transport in the blood and storage Lipid Triglyceride
Shortening is any fat, a solid at room temperature and used to make crumbly pastry and other food products. Although butter is solid at room temperature and is used in making pastry, the term "shortening" refers to butter, but is more related to margarine. Shortening was synonymous with lard, but with the invention of margarine from beef tallow by French chemist Hippolyte Mège-Mouriès in 1869, margarine came to be included in the term. Since the invention of hydrogenated vegetable oil in the early 20th century, "shortening" has come exclusively to mean hydrogenated vegetable oil. Modern margarine is made of refined vegetable oil and water, may contain milk. Vegetable shortening shares many properties with lard: Both are semi-solid fats with a higher smoke point than butter and margarine, they are thus less prone to splattering, making them safer for frying. Lard and shortening have a higher fat content compared to about 80 % for margarine. Cake margarines and shortenings tend to contain a few percent of monoglycerides whereas other margarines have less.
Such "high ratio shortenings" blend better with hydrophilic ingredients such as starches and sugar. Hydrogenation of organic substances was first developed by the French chemist Paul Sabatier in 1897, in 1901 the German chemist Wilhelm Normann developed the hydrogenation of fats, which he patented in 1902. In 1907, a German chemist, Edwin Cuno Kayser, moved to Cincinnati, the home town of soap manufacturer Procter & Gamble, he had worked for British soap manufacturer Joseph Crosfield and Sons and was well acquainted with Normann's process, as Crosfield and Sons owned the British rights to Normann's patent. Soon after arriving, Kayser made a business deal with Procter & Gamble, presented the company with two processes to hydrogenate cottonseed oil, with the intent of creating a raw material for soap. Since the product looked like lard, Procter & Gamble instead began selling it as a vegetable fat for cooking purposes in June 1911, calling it "Crisco", a modification of the phrase "crystallized cottonseed oil".
While similar to lard, vegetable shortening was much cheaper to produce. Shortening required no refrigeration, which further lowered its costs and increased its appeal in a time when refrigerators were rare. With these advantages, plus an intensive advertisement campaign by Procter & Gamble, Crisco gained popularity in American households; as food production became industrialized and manufacturers sought low-cost raw materials, the use of vegetable shortening became common in the food industry. In addition, vast US government-financed surpluses of cottonseed oil, corn oil, soy beans helped create a market in low-cost vegetable shortening. Crisco, owned by The J. M. Smucker Company since 2002, remains the best-known brand of shortening in the US, nowadays consisting of a blend of and hydrogenated soybean and palm oils. In Ireland and the UK, Trex is a popular brand, while in Australia, Copha is popular, although made from coconut oil. A short dough is one, crumbly or mealy; the opposite of a short dough is dough that stretches.
Vegetable shortening can produce both types of dough. To produce a short dough, used for tarts, the shortening is cut into the flour with a pastry blender, pair of table knives, fingers, or other utensil until the resulting mixture has a fine, cornmeal-like texture. For a long dough, the shortening is cut in only until the pea-sized crumbs are formed, or larger lumps may be included. After cutting in the fat, the liquid is added and the dough is shaped for baking. Neither short dough nor long flake dough stirred batters. In the early twenty-first century, artificial shortening became the subject of some health concerns due to its traditional formulation from hydrogenated vegetable oils that contain trans-fatty acids, or "trans fats", a type not found in significant amounts in any occurring food, that have been linked to a number of adverse health effects. A low trans fat variant of Crisco was introduced in 2004. In January 2007, all Crisco products were reformulated to contain less than one gram of trans fat per serving, the separately marketed trans-fat free version introduced in 2004 was discontinued.
In 2006, Cookeen was reformulated to remove trans fats. William Shurtleff and Akiko Aoyagi, 2007. History of Soy Oil Shortening: A Special Report on The History of Soy Oil, Soybean Meal, & Modern Soy Protein Products, from the unpublished manuscript, History of Soybeans and Soy foods: 1100 B. C. to the 1980s. Lafayette, California: Soyinfo Center