malic acid


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malic acid:

see Krebs cycleKrebs cycle,
series of chemical reactions carried out in the living cell; in most higher animals, including humans, it is essential for the oxidative metabolism of glucose and other simple sugars.
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Malic Acid

 

(also called hydroxysuccinic acid), HOOCCH2CH(OH)COOH, a dibasic hydroxycarboxylic acid. Malic acid takes the form of a colorless, hygroscopic, crystalline compound that is readily soluble in water and ethyl alcohol; it has a melting point of 100°C.

Malic acid was first isolated by K. Scheele, who in 1785 obtained it from unripe apples. The L-form of the acid is found in plants either in the free state or as acid salts; the presence of either the acid or salt makes possible the acid reaction of cell fluid. Fruits rich in malic acid include barberries, raspberries, apples, and the berries of the mountain ash; the vegetative organs of succulents, especially Crassulaceae, also contain considerable amounts of the acid. The tobacco plants Nicotiana rustica and Nicotiana tabacum contain the nicotine salts of the acid.

Malic acid is an intermediate in cell respiration—in the tricarboxylic acid cycle and its variant, the glyoxylate cycle. In plants containing considerable amounts of organic acids (for example, rhubarb, begonia, and dock), free ammonia is rendered harmless by the formation of the ammonium salts of organic acids, including malic acid. Malic acid is used by many microorganisms as an energy substrate or a source of carbon. It is formed as a by-product in various types of fermentation.

Malic acid is used in the production of fruit drinks and candies.

E. P. FEDENKO

malic acid

[′mal·ik ′as·əd]
(biochemistry)
COOH·CH2·CHOH·COOH Hydroxysuccinic acid: a dibasic hydroxy acid existing in two optically active isomers and a racemate form; found in apples and many other fruits.
References in periodicals archive ?
In grapes, tartaric acid and malic acids consist of the 90 % of total organic acids (Agaoglu, 2002).
Nitrogen application in the form of organic compost and urea did not affect the pH values, total acidity, soluble solids and tartaric and malic acid in the Cabernet Sauvignon grape must (Table 3).
Food acidulants such as acetic acid, citric acid, lactic acid, malic acid, and phosphoric acid have preservative, stabilizing, antimicrobial, and pH-regulating properties that increase the shelf life of food and beverages.
In terms of organic acid content, malic acid was identified to be the predominant organic acid with a content of 1.
Malic acid is the principal acid in loquat that contributes 90% of the total organic acid content of fruit (Ding et al.
Malic acid occurs naturally in fruits and many vegetables.
Analysis of organic acids: The standards used in organic acid analyses (succinic acid, malic acid, oxalic acid, fumaric acid and citric acid) were obtained from Sigma company (St.
While malic acid determines the more agreeably perceived fruity acidity, pyruvic acid is responsible for the caramel sour taste of the coffee beverage.
The institute says "flue-cured Virginia tobacco is a better source for extraction of solanesol and air-cured tobaccos like bidi, natu & chewing are ideal for recovery of nicotine and organic acids" such as malic acid and citric acid.
The home remedy contains malic acid, a mild astringent.
The malolactic wine yeast, ML01, constructed in my laboratory, conducts the alcoholic fermentation and degrades malic acid to lactic acid during the alcoholic fermentation.
the hidden potentiality of NCSA as an oxidant and malic acid as the substrate.