lactic acid

n. A syrupy, water-soluble liquid, C₃H₆O₃, produced by anaerobic glucose metabolism in muscles, by certain bacteria, and by synthetic methods. Lactic acid is present in fermented foods such as yogurt and sauerkraut and is used in foods and beverages as a flavoring and preservative, in dyeing and textile printing, and in pharmaceuticals.

lactic acid

n (Elements & Compounds) a colourless syrupy carboxylic acid found in sour milk and many fruits and used as a preservative (E270) for foodstuffs, such as soft margarine, for making pharmaceuticals and adhesives, and produced in muscle tissue during strenuous exercise. Formula: CH3CH(OH)COOH. Systematic name: 2-hydroxypropanoic acid

lac′tic ac′id

n. a syrupy liquid, C₃H₆O₃, produced by anaerobic metabolism, as in the fermentation of milk or carbohydrates. [1780–90]

lac·tic acid

(lăk′tĭk) An organic acid produced when milk sours or various fruits ferment. It is used as a flavoring and preservative for foods. Lactic acid is also produced by muscle tissue during exercise, especially when oxygen supply is limited, and can cause cramping pains.

lactic acid

A waste product of anaerobic respiration that accumulates in muscles during exercise.

Thesaurus

Noun

lactic acid - a clear odorless hygroscopic syrupy carboxylic acid found in sour milk and in many fruitscarboxylic acid - an organic acid characterized by one or more carboxyl groups

Translations

lactic acid

lactic acid,

CH₃CHOHCO₂H, a colorless liquid organic acid. It is miscible with water or ethanol. Lactic acid is a fermentation product of lactose (milk sugar); it is present in sour milk, koumiss, leban, yogurt, and cottage cheese. The protein in milk is coagulated (curdled) by lactic acid. Lactic acid is produced in the muscles during intense activity by the breakdown of glucose, and may be used by muscle cells as a source of energy. Calcium lactate, a soluble lactic acid salt, is used as a source of calcium in the diet. Lactic acid is produced commercially for use in pharmaceuticals and foods, in leather tanning and textile dyeing, and in making plastics, solvents, inks, and lacquers. Although it can be prepared by chemical synthesis, production of lactic acid by fermentation of glucose and other substances is a less expensive method. Chemically, lactic acid occurs as two optical isomersisomer
, in chemistry, one of two or more compounds having the same molecular formula but different structures (arrangements of atoms in the molecule). Isomerism is the occurrence of such compounds. Isomerism was first recognized by J. J. Berzelius in 1827.
..... Click the link for more information. , a dextro and a levo form; only the levo form takes part in animal metabolism. The lactic acid of commerce is usually an optically inactive racemic mixture of the two isomers.

Lactic Acid

(α-hydroxypropionic acid, CH₃CH(OH)-COOH), a monobasic hydroxycarboxylic acid; an important intermediate metabolite in animals, plants, and microorganisms.

Lactic acid occurs as colorless water-soluble crystals. It exists in two optically active forms, (−) and (+), with a melting point of 25°–26°C, and in an inactive racemic form, (±), with a melting point of 18°C. The (−) and (+) lactic acids undergo racemization at 130°–150°C and produce salts (lactates) and esters similar to carboxylic acids.

Lactic acid is formed during the fermentation of sugary substances by various species of lactic acid bacteria (for example, during the souring of milk, the pickling of cabbage and vegetables, the aging of cheese, and ensilage). Either a racemate or one of the optically active forms of lactic acid is produced, depending on the species of bacteria and the type of sugar present. The industrial fermentation of cane sugar, dextrose, and maltose by Bacillus Delbrucki yields (±) lactic acid, which is used to delime leather in tanning and for chromate reduction in mordanting chrome. Lactic acid salts are used as mordants in dyeing and printing, and lactic acid esters as varnish thinners.

In animal tissue (primarily muscle), the formation of (+) lactic acid is the final stage in the anaerobic enzymic breakdown of carbohydrates, or glycolysis. In the absence of O₂, the amount of lactic acid produced in muscle tissue equals the amount of glycogen lost. (Muscle fatigue is associated with the depletion of glycogen reserves and the accumulation of lactic acid.) In the presence of O₂, approximately 20 percent of the lactic acid is oxidized to CO₂ and H₂O, the energy released is used to convert the remaining lactic acid to glycogen, and the onset of fatigue is more gradual. The reversible reduction of pyruvic acid (pyruvate) to lactic acid (lactate) occurs during the final stage of glycolysis upon the action of lactate dehydrogenase. Plants and microorganisms produce lactic acid by pyruvate reduction.

V. N. FROSIN

lactic acid

[′lak·tik ′as·əd] (biochemistry) C₃H₆O₃ A hygroscopic α-hydroxy acid, occurring in three optically isomeric forms:Lform, in blood and muscle tissue as a product of glucose and glycogen metabolism;Dform, obtained by fermentation of sucrose; andDLform, a racemic mixture present in foods prepared by bacterial fermentation, and also made synthetically.

lactic acid

a colourless syrupy carboxylic acid found in sour milk and many fruits and used as a preservative (E270) for foodstuffs, such as soft margarine, and for making pharmaceuticals and adhesives. Formula: CH₃CH(OH)COOH

lactic acid

lactic

[lak´tik] pertaining to milk.lactic acid a metabolic intermediate involved in many biochemical processes; it is the end product of glycolysis, which provides energy anaerobically in skeletal muscle during heavy exercise, and it can be oxidized aerobically in the heart for energy production or can be converted back to glucose (gluconeogenesis) in the liver. Moderate elevations of blood lactate occur during heavy exercise; severe elevations (lactic acidosis) can occur in diabetes mellitus and in genetic deficiencies of enzymes involved in gluconeogenesis. Lactate is also the end product of fermentation in several bacterial species. The sodium salt of racemic or inactive lactic acid (sodium lactate) is used as an electrolyte and fluid replenisher.

lac·tic ac·id

(lak'tik as'id), A normal intermediate in the fermentation (oxidation, metabolism) of sugar. In pure form, a syrupy, odorless, and colorless liquid obtained by the action of the lactic acid bacillus on milk or milk sugar; in concentrated form, a caustic used internally to prevent gastrointestinal fermentation. A culture of the bacillus, or milk containing it, is usually given in place of the acid. l-Lactic acid is also known as sarcolactic acid.

lactic acid

lac·tic ac·id

(lak'tik as'id) A normal intermediate in glycosis.

lactic acid

An acid formed when muscles are strongly contracted for long periods. Also formed from carbohydrates in the vagina by the action of DODERLEIN'S BACILLUS. Lactic acid is an ingredient in a range of drug formulations.

lactic acid

an organic acid (CH₃ CH(OH)COOH) produced from pyruvic acid as a result of ANAEROBIC RESPIRATION in microorganisms (see LACTOSE and in the active muscles of animals (see OXYGEN DEBT), the hydrogenation of pyruvate being catalysed by lactic dehydrogenase (LDH). In animals the acid can be oxidized back to pyruvate (using LDH again) when sufficient oxygen is available, most of the conversion taking place in the liver.

lac·tic ac·id

(lak'tik as'id) Normal intermediate in the fermentation of sugar. In concentrated form, a caustic used internally to prevent gastrointestinal fermentation.

lactic acid

lactic acid

lactic acid

lac′tic ac′id

lac·tic acid

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lactic acid,

Lactic Acid

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lactic

lac·tic ac·id

lactic acid

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lactic acid

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lactic acid

Words related to lactic acid

noun a clear odorless hygroscopic syrupy carboxylic acid found in sour milk and in many fruits

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