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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 isomers, 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.

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"lactic acid." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 23 Jun. 2017 <http://www.encyclopedia.com>.

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lactic acid

lactic acid The acid produced by the anaerobic fermentation of carbohydrates. Originally discovered in sour milk, it is responsible for the flavour of fermented milk and for the precipitation of the casein curd in cottage cheese. Also produced by fermentation in silage, pickles, sauerkraut, cocoa, and tobacco, its value here is in suppressing the growth of unwanted organisms, and as the product of glucose metabolism in muscle under conditions of maximum exertion.

Used as an acidulant (as well as citric and tartaric acids) in sugar confectionery, soft drinks, pickles, and sauces.

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lactic acid

lactic acid (2-hydroxypropanoic acid) An alpha hydroxy carboxylic acid, CH3CH(OH)COOH, with a sour taste. Lactic acid is produced from pyruvic acid in active muscle tissue when oxygen is limited (see oxygen debt) and subsequently removed for conversion to glucose by the liver. During strenuous exercise it may build up in the muscles, causing cramplike pains. It is also produced by fermentation in certain bacteria and is characteristic of sour milk.

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"lactic acid." A Dictionary of Biology. . Encyclopedia.com. 23 Jun. 2017 <http://www.encyclopedia.com>.

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lactic acid

lactic acid Colourless, organic acid (2-hydroxypropanoic acid, CH3CHOHCOOH) formed from lactose by the action of bacteria. It is also produced in muscles, where it causes muscle fatigue, when anaerobic respiration occurs due to insufficient oxygen. Lactic acid is used in foods and beverages, in tanning, dyeing, and adhesive manufacture. Properties: r.d. 1.206; m.p. 18°C (64.4°F); b.p. 122°C (252°F).

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"lactic acid." World Encyclopedia. . Encyclopedia.com. 23 Jun. 2017 <http://www.encyclopedia.com>.

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lactic acid

lactic acid (lak-tik) n. a compound that forms in the cells as the end-product of glucose metabolism in the absence of oxygen (see glycolysis). Lactic acid (owing to its low pH) is an important food preservative.

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lactic acid

lactic acid A 3-carbon hydroxy-acid that is formed as the major metabolic product of certain bacteria (and also from pyruvic acid in animal cells when glycolysis occurs under anaerobic conditions).

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"lactic acid." A Dictionary of Plant Sciences. . Encyclopedia.com. 23 Jun. 2017 <http://www.encyclopedia.com>.

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lactic acid

lac·tic ac·id • n. Biochem. a colorless syrupy organic acid, CH3CH(OH)COOH, formed in sour milk, and produced in the muscle tissues during strenuous exercise.

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"lactic acid." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 23 Jun. 2017 <http://www.encyclopedia.com>.

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lactic acid

lactic acid A three-carbon hydroxyacid, formed as the major metabolic product of certain bacteria, and also from pyruvic acid in animal cells when glycolysis occurs under anaerobic conditions.

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