| Lactic acid | |
|---|---|
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| IUPAC name | 2-hydroxypropanoic acid |
| Identifiers | |
| CAS number | 50-21-5 L: 79-33-4 D: 10326-41-7 D/L: 598-82-3 |
| SMILES | CC(O)C(=O)O |
| Properties | |
| Molecular formula | C3H6O3 |
| Molar mass | 90. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 08 g/mol |
| Melting point |
L: 53 °C |
| Boiling point |
122 °C @ 12 mmHg |
| Acidity (pKa) | 3. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 85 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Lactic acid (IUPAC systematic name: 2-hydroxypropanoic acid), also known as milk acid, is a chemical compound that plays a role in several biochemical processes. In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly The International Union of Pure and Applied Chemistry ( IUPAC) (aɪjuːpæk or ay-yoo-pec) is an international Non-governmental organization There are millions of possible objects that can be described in science too many to create Common names for every one A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as It was first isolated in 1780 by a Swedish chemist, Carl Wilhelm Scheele, and is a carboxylic acid with a chemical formula of C3H6O3. Carl Wilhelm Scheele (9 December 1742 &ndash 21 May 1786 was a German - Swedish pharmaceutical chemist born in Stralsund, Western Pomerania, Carboxylic acids are Organic acids characterized by the presence of a Carboxyl group, which has the formula -C(=OOH usually written -COOH or -CO2H A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes It has a hydroxyl group adjacent to the carboxyl group, making it an alpha hydroxy acid (AHA). Hydroxyl in Chemistry stands for a molecule consisting of an Oxygen atom and a Hydrogen atom connected by a Covalent bond. Carboxyl group or CO2H is a Functional group present in Amino acids and Carboxylic acids Its structure is composed of one carbon atom attached α-hydroxy acids, or alpha hydroxy acids ( AHAs) are a class of chemical compounds that consist of a Carboxylic acid substituted with a hydroxy group In solution, it can lose a proton from the acidic group, producing the lactate ion CH3CH(OH)COO−. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge It is miscible with water or ethanol, and is hygroscopic. Hygroscopy is the ability of a substance to attract Water Molecules from the surrounding environment through either absorption or Adsorption
Lactic acid is chiral and has two optical isomers. The term chiral (pronounced /ˈkaɪɹ(əl̩/ is used to describe an object that is non- superimposable on its mirror image The term chiral (pronounced /ˈkaɪɹ(əl̩/ is used to describe an object that is non- superimposable on its mirror image One is known as L-(+)-lactic acid or (S)-lactic acid and the other, its mirror image, is D-(-)-lactic acid or (R)-lactic acid. L-(+)-Lactic acid is the biologically important isomer.
In animals, L-lactate is constantly produced from pyruvate via the enzyme lactate dehydrogenase (LDH) in a process of fermentation during normal metabolism and exercise. Pyruvic acid (CH3COCO2H is an alpha-keto acid. The Carboxylate Anion of pyruvic acid is known as pyruvate. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins Lactate dehydrogenase ( LDH) is an Enzyme ( present in a wide variety of organisms including plants and animals Fermentation is the process of deriving energy from the oxidation of organic compounds such as carbohydrates using an endogenous electron acceptor which is Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. It does not increase in concentration until the rate of lactate production exceeds the rate of lactate removal which is governed by a number of factors including: monocarboxylate transporters, concentration and isoform of LDH and oxidative capacity of tissues. The concentration of blood lactate is usually 1-2 mmol/L at rest, but can rise to over 20 mmol/L during intense exertion. Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products
Industrially, lactic acid fermentation is performed by Lactobacillus bacteria, among others. Lactic acid fermentation is a biological process by which sugars such as Glucose, Fructose, and Sucrose, are converted into cellular energy and the metabolic Lactobacillus is a Genus of Gram-positive Facultative anaerobic or Microaerophilic Bacteria. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have These bacteria can operate in the mouth; the acid they produce is responsible for the tooth decay known as caries. The mouth, buccal cavity, or oral cavity is the first portion of the Alimentary canal that receives food and begins digestion by mechanically breaking up In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are Caries is a progressive destruction of any kind of Bone structure including the Skull, Ribs and other bones or the teeth.
In medicine, lactate is one of the main components of Ringer's lactate or lactated Ringer's solution (Compound Sodium Lactate or Hartmann's Solution in the UK). Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the Lactated Ringer's solution is a solution that is isotonic with Blood and intended for intravenous administration. Hartmann's solution or Compound Sodium Lactate is a solution that is isotonic with Blood and intended for intravenous administration. Hartmann's solution or Compound Sodium Lactate is a solution that is isotonic with Blood and intended for intravenous administration. This intravenous fluid consists of sodium and potassium cations, with lactate and chloride anions, in solution with distilled water in concentration so as to be isotonic compared to human blood. Intravenous therapy or IV therapy is the giving of Liquid substances directly into a Vein. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge The chloride Ion is formed when the element Chlorine picks up one Electron to form an Anion (negatively-charged ion Cl&minus An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Water is a common Chemical substance that is essential for the survival of all known forms of Life. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products It is most commonly used for fluid resuscitation after blood loss due to trauma, surgery, or a burn injury. Treatment of physical trauma is described here and in First aid. Surgery (from the χειρουργική cheirourgikē, via chirurgiae meaning "hand work" is a medical specialty that uses operative manual and instrumental A burn is a type of Injury that may be caused by Heat, cold, Electricity, Chemicals, Light, Radiation, or
Contents |
Exercise and lactate
During power-intensive exercises such as sprinting, when the rate of demand for energy is high, lactate is produced faster than the ability of the tissues to remove it and lactate concentration begins to rise. This is a beneficial process since the regeneration of NAD+ ensures that energy production is maintained and exercise can continue. Nicotinamide adenine dinucleotide, abbreviated NAD+, is a Coenzyme found in all living cells The compound is a dinucleotide since it consists The increased lactate produced can be removed in a number of ways including
- oxidation to pyruvate by well-oxygenated muscle cells which is then directly used to fuel the citric acid cycle
- conversion to glucose via the Cori cycle in the liver through the process of gluconeogenesis. Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state Muscle (from Latin musculus, diminutive of mus "mouse" is contractile tissue of the body and is derived from the The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called The citric acid cycle, also known as the tricarboxylic acid cycle ( TCA cycle) or the Krebs cycle, (or rarely the Szent-Györgyi–Krebs cycle Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. The Cori cycle, named after its discoverers Carl Cori and Gerty Cori, refers to the metabolic pathway in which lactate produced by anaerobic Glycolysis Gluconeogenesis (abreviated GNG) is a Metabolic pathway that results in the generation of Glucose from non- Carbohydrate carbon substrates such
Contrary to popular belief, this increased concentration of lactate does not directly cause acidosis, nor is it responsible for delayed onset muscle soreness. Acidosis is an increased Acidity (ie an increased Hydrogen ion Concentration) Delayed onset muscle soreness (DOMS also sometimes called muscle fever, is the pain or discomfort often felt 24 to 72 hours after exercising and subsides generally within 2 [1] This is because lactate itself is not capable of releasing a proton, and secondly, the acidic form of lactate, lactic acid, cannot be formed under normal circumstances in human tissues. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Analysis of the glycolytic pathway in humans indicates that there are not enough hydrogen ions present in the glycolytic intermediates to produce lactic or any other acid.
The acidosis that is associated with increases in lactate concentration during heavy exercise arises from a separate reaction. Acidosis is an increased Acidity (ie an increased Hydrogen ion Concentration) When ATP is hydrolysed, a hydrogen ion is released. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Hydrolysis is a Chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions which may go on to participate in further reactions ATP-derived hydrogen ions are primarily responsible for the decrease in pH. During intense exercise, aerobic metabolism cannot produce ATP quickly enough to supply the demands of the muscle. Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from As a result, anaerobic metabolism becomes the dominant energy producing pathway as it can form ATP at high rates. Lactic acid fermentation is a biological process by which sugars such as Glucose, Fructose, and Sucrose, are converted into cellular energy and the metabolic Due to the large amounts of ATP being produced and hydrolysed in a short period of time, the buffering systems of the tissues are overcome, causing pH to fall and creating a state of acidosis, a natural process which facilitates the easier dissociation of Oxyhaemoglobin and allows easier transfer of oxygen from the blood[2]. For an individual weak acid or weak base component see Buffering agent. Hemoglobin ( also spelled haemoglobin and abbreviated Hb or Hgb) is the Iron -containing Oxygen -transport Metalloprotein This may be one factor, among many, that contributes to the acute muscular discomfort experienced shortly after intense exercise.
The effect of lactate on acidosis has been the topic of many recent conferences in the field of exercise physiology. Robergs et al. have accurately chased the proton movement that occurs during glycolysis. However, in doing so, they have suggested that [H+] is an independent variable that determines its own concentration. A recent review by Lindinger et al. has been written to rebut the stoichiometric approach used by Robergs et al (2004). [1] In using this stoichiometric process, Robergs et al. have ignored the causative factors (independent variables) of the concentration of hydrogen ions (denoted [H+]). These factors are strong ion difference [SID], PCO2, and weak acid buffers. Lactate is a strong anion, and causes a reduction in [SID] which causes an increase in [H+] to maintain electroneutrality. PCO2 also causes an increase in [H+]. During exercise, the intramuscular lactate concentration and PCO2 increase, causing an increase in [H+], and thus a decrease in pH. (See Le Chatelier's principle)
Lactic acid as a polymer precursor
Two molecules of lactic acid can be dehydrated to lactide, a cyclic lactone. In Chemistry, Le Chatelier's Principle, also called the Le Chatelier-Braun principle, can be used to predict the effect of a change in conditions on a Chemical Polylactic acid or polylactide ( PLA) is a Biodegradable, Thermoplastic, Aliphatic Polyester derived from renewable resources Lactide is the cyclic di- Ester of Lactic acid, ie 2-hydroxypropionic acid A variety of catalysts can polymerise lactide to either heterotactic or syndiotactic polylactide, which as biodegradable polyesters with valuable (inter alia) medical properties are currently attracting much attention. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Tacticity (from Greek 'taktikos' of or relating to arrangement or order is the relative Stereochemistry of adjacent chiral centers within a Macromolecule Polylactic acid or polylactide ( PLA) is a Biodegradable, Thermoplastic, Aliphatic Polyester derived from renewable resources Biodegradation is the process by which organic substances are broken down by the enzymes produced by living organisms Polyester is a category of Polymers which contain the Ester Functional group in their main chain
Nowadays, lactic acid is used as a monomer for producing polylactic acid (PLA) which later has application as biodegradable plastic. Polylactic acid or polylactide ( PLA) is a Biodegradable, Thermoplastic, Aliphatic Polyester derived from renewable resources This kind of plastic is a good option for substituting conventional plastic produced from petroleum oil because of low emission of carbon dioxide that can contribute to global warming. The commonly used process in producing lactic acid is via fermentation, and later to obtain the polylactic acid, the polymerization process follows.
Lactic acid in foods
Lactic acid is primarily found in sour milk products, such as: koumiss, leban, yogurt, kefir and some cottage cheeses. Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes. Kumis ( Turkish:kımız Mongolian:airag is a fermented dairy product traditionally made from mare's milk Yoghurt, yogurt, yoghourt, youghurt or yogourt (see spelling below is a For the Islamic term see Kaffir. Kefir (alternately keefir, kephir, kewra, talai, mudu kekiya Cottage cheese is a Cheese Curd product with a mild flavor It is drained but not pressed so some Whey remains The casein in fermented milk is coagulated (curdled) by lactic acid. See Casein paint for information about casein usage in artistic painting
Although it can be fermented from lactose (milk sugar), most commercially used lactic acid is derived by using bacteria such as Bacillus acidilacti, Lactobacillus delbueckii or Lactobacillus bulgaricus to ferment carbohydrates from nondairy sources such as cornstarch, potatoes and molasses. Fermentation in Food processing typically refers to the conversion of Sugar to Alcohol using Yeast under Anaerobic conditions Lactose (also referred to as milk sugar) is a Sugar which is found most notably in Milk. Lactobacillus delbrueckii subspecies bulgaricus (also known as Lactobacillus bulgaricus) is one of several bacteria used for the production of Yogurt. Cornstarch, or cornflour, is the Starch of the Maize grain commonly known as Corn. The potato is a Starchy Tuberous crop Vegetable from the perennial Solanum tuberosum of the Solanaceae Molasses or Treacle is a thick Syrup by-product from the processing of the Sugarcane or Sugar beet into Sugar. Thus, although it is commonly known as "milk acid", vegan products can contain lactic acid as an ingredient.
Lactic acid may also be found in various processed foods, usually either as a pH adjusting ingredient, or as a preservative (either as antioxidant or for control of pathogenic micro-organisms). A preservative is a natural or synthetic chemical that is added to products such as foods pharmaceuticals paints biological samples wood etc An antioxidant is a Molecule capable of slowing or preventing the oxidation of other molecules It may also be used as a fermentation booster in rye and sourdough breads. Bread is a Staple food prepared by Baking a Dough of Flour and Water. [3]
Lactic acid is also present in wheat beers, especially lambic, due to the activity of Pediococcus damnosus. Wheat beer is a Beer that is brewed with a significant proportion of Wheat. Lambic is a very distinctive type of Beer brewed only in the Pajottenland region of Belgium (southwest of Brussels) [4]
Lactic acid is widely used for inhibiting pathogenic bacteria like E. coli, Salmonella, Campylobacter and Listeria on animal carcasses like beef, pork and poultry during the slaughtering process.
Potassium lactate, sodium lactate and calcium lactate are the neutralized salts of lactic acid. Potassium lactate is used in many fresh and cooked meat products for shelf life control, color preservation and reduction of sodium content. Sodium lactate has a mild saline taste and is therefore suitable for flavour enhancement in meat products as well. Sodium lactate is being produced as liquids as well as powders. Calcium lactate is popular for fortification and improved texture in emulsified meat products like frankfurters. [5]
See also
References
- ^ a b R. The Cori cycle, named after its discoverers Carl Cori and Gerty Cori, refers to the metabolic pathway in which lactate produced by anaerobic Glycolysis The alanine cycle is quite similar to the Cori cycle. When muscles produce lactate during times of decreased oxygen they also produce Alanine. For information on plastics which are biodegradable see Biodegradable plastic. 2-Hydroxybutyric acid (or alpha -hydroxybutyrate) is a Hydroxybutyric acid with the Hydroxyl group on the carbon adjacent to the Carboxyl Robergs, F. Ghiasvand, D. Parker (2004). "Biochemistry of exercise-induced metabolic acidosis". Am J Physiol Regul Integr Comp Physiol 287 (3): R502-16. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 15308499.
- ^ Siggaard-Andersen, O & OH Gøthgen (1995) Oxygen and acid-base parameters of arterial and mixed venous blood. Relevant versus redundant. Acta Anaesthesiol Scand 39. Suppl 107, 21-27
- ^ "Food Applications". Galactic Div. of Finasucre. 2006. http://www.lactic.com/
- ^ The Lambic Beers
- ^ Applications of lactates in meat and meat products, PURAC, a CSM company http://www.purac.com
External links
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