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Malic acid is a 2-hydroxydicarboxylic acid that is succinic acid in which one of the hydrogens attached to a carbon is replaced by a hydroxy group.
Malic acid has a role as a food acidity regulator and a fundamental metabolite.
Malic acid is a 2-hydroxydicarboxylic acid and a C4-dicarboxylic acid.
CAS: 6915-15-7
MF: C4H6O5
MW: 134.09
EINECS: 230-022-8
Synonyms
alpha-Hydroxysuccinic acid;alpha-hydroxysuccinicacid;Butanedioic acid, hydroxy-;commonmalicacid;deoxytetraricacid;femanumber2655;hydroxy-butanedioicaci;Hydroxyethane-1,2-dicarboxylic acid
Malic acid derives from a succinic acid.
Malic acid is a conjugate acid of a malate(2-) and a malate.
Malic acid is an organic compound with the molecular formula HO2CCH(OH)CH2CO2H.
Malic acid is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive.
Malic acid has two stereoisomeric forms (L- and D-enantiomers), though only the L-isomer exists naturally.
The salts and esters of malic acid are known as malates.
The malate anion is a metabolic intermediate in the citric acid cycle.
Malic acid, with the CAS number 6915-15-7, is a naturally occurring organic compound classified as a dicarboxylic acid.
Malic acid is characterized by its two carboxyl functional groups (-COOH), which contribute to its acidic properties.
Malic acid is a colorless, crystalline solid that is soluble in water and exhibits a tart flavor, commonly found in various fruits, particularly apples.
Malic acid plays a significant role in the Krebs cycle, a crucial metabolic pathway for energy production in living organisms.
Malic acid has a molecular formula of C4H6O5 and a molecular weight of approximately 134.09 g/mol.
In addition to its biological significance, malic acid is utilized in the food and beverage industry as a flavoring agent and acidulant, enhancing the taste of products.
Malic acid also finds applications in cosmetics and pharmaceuticals due to its exfoliating properties.
Overall, malic acid is valued for its multifunctional roles across various industries, owing to its unique chemical structure and properties.
Malic Acid is an organic compound that occurs naturally in a wide variety of unripe fruits, including apples, cherries, and tomatoes.
Malic acid is used as a flavoring and in the aging of wine.
Malic acid Chemical Properties
Melting point: 131-133 °C (lit.)
Boiling point: 167.16°C (rough estimate)
alpha: [α]D20 -0.5～+0.5° (c=5, H2O)
bulk density: 800kg/m3
density: 1.609
vapor density: 4.6 (vs air)
vapor pressure: <0.1 mm Hg ( 20 °C)
refractive index: 1.3920 (estimate)
Fp: 203 °C
storage temp.: 2-8°C
solubility methanol: 0.1 g/mL, clear, colorless
pka: 3.4(at 25℃)
form: Solid
color: White to Almost white
Odor: at 100.00 %. odorless
PH: 3.33(1 mM solution);2.74(10 mM solution);2.21(100 mM solution);
Odor Type: odorless
biological source: synthetic
Optical Rotation: [α]/D 0.10 to +0.10°
Water Solubility: 558 g/L (20 ºC)
Merck: 14,5707
BRN: 1723539
Henry's Law Constant: 2.7×108 mol/(m3Pa) at 25℃, Compernolle and Müller (2014)
Major Application: pharmaceutical (small molecule)
Cosmetic Ingredient Review (CIR): Malic acid (6915-15-7)
InChI: 1S/C4H6O5/c5-2(4(8)9)1-3(6)7/h2,5H,1H2,(H,6,7)(H,8,9)
InChIKey: BJEPYKJPYRNKOW-UHFFFAOYSA-N
LogP: -6.14 at 20℃
CAS DataBase Reference: 6915-15-7(CAS DataBase Reference)
NIST Chemistry Reference: Hydroxybutanedioic acid(6915-15-7)
EPA Substance Registry System: Malic acid (6915-15-7)
White or nearly white, crystalline powder or granules having a slight odor and a strongly acidic taste.
Malic acid is hygroscopic.
The synthetic material produced commercially in Europe and the USA is a racemic mixture, whereas the naturally occurring material found in apples and many other fruits and plants is levorotatory.
Uses
Malic Acid is an acidulant that is the predominant acid in apples. it exists as white crystalline powder or granules and is considered hygroscopic.
As compared to citric acid, Malic acid is slightly less soluble but is still readily soluble in water with a solubility of 132 g/100 ml at 20°c.
Malic acid has a stronger apparent acid taste and has a longer taste retention than citric acid which peaks faster but does not mask the aftertaste as effectively.
A quantity of 0.362–0.408 kg of malic acid is equivalent to 0.453 kg of citric acid and to 0.272–0.317 kg of fumaric acid in tartness.
At temperatures above 150°c Malic acid begins to lose water very slowly to yield fumaric acid.
Malic acid is used in soft drinks, dry-mix beverages, puddings, jellies, and fruit filling.
Malic acid is used in hard can- dies because it has a lower melting point (129°c) than citric acid which improves the ease of incorporation.
Malic acid, HOOCCH(OH).CH2COOH, also known as hydroxysuccinic acid, is a colorless solid.
Malic acid is soluble in water and alcohol.
Malic acid exists in two optically active forms and a racemic mixture.
Malic acid is used in medicine and found in apples and other fruits.
The naturally occuring isomer is the L-form which has been found in apples and many other fruits and plants.
Selective α-amino protecting reagent for amino acid derivatives.
Versatile synthon for the preparation of chiral compounds including κ-opioid rece.
malic acid is the third smallest alpha hydroxy acid in terms of molecular size.
Although Malic acid is used in numerous cosmetic products, particularly those indicating a “fruit acid” content and generally designed for anti-aging, unlike glycolic and lactic acids, its skin benefits have not been extensively studied.
Some formulators consider Malic acid difficult to work with, particularly when compared to other AHAs, and it can be somewhat irritating.
Malic acid is rarely used as the only AHA in a product.
Malic acid is found naturally occurring in apples.
Pharmaceutical Applications
Malic acid is used in pharmaceutical formulations as a generalpurpose acidulant.
Malic acid possesses a slight apple flavor and is used as a flavoring agent to mask bitter tastes and provide tartness.
Malic acid is also used as an alternative to citric acid in effervescent powders, mouthwashes, and tooth-cleaning tablets.
In addition, malic acid has chelating and antioxidant properties.
Malic acid may be used with butylated hydroxytoluene as a synergist in order to retard oxidation in vegetable oils.
In food products Malic acid may be used in concentrations up to 420 ppm.
Therapeutically, malic acid has been used topically in combination with benzoic acid and salicylic acid to treat burns, ulcers, and wounds.
Malic acid has also been used orally and parenterally, either intravenously or intramuscularly, in the treatment of liver disorders, and as a sialagogue.
Production Methods
Malic acid is manufactured by hydrating maleic and fumaric acids in the presence of suitable catalysts.
The malic acid formed is then separated from the equilibrium product mixture.
Biotechnological Production
Malic acid as well as L-malic acid can be used in beverage, food, and animal nutrition.
Malic acid is mainly derived from chemical synthesis, whereas L-malic acid is produced biotechnologically by enzymatic or fermentative processes.
Fumaric acid can be converted to L-malic acid using fumarases.
Different microorganisms (e.g. Brevibacterium flavum, Brevibacterum ammoniagenes, and Corynebacterium species) are able to form naturally high amounts of fumarase intracellularly. For example, B. flavum has been immobilized in j-carrageenan and polyethyleneimine for whole-cell biocatalysis.
A fumarase activity of 2.16 mmol.ml(gel)-1.h -1 at 55 C has been reported.
This process has been used to produce 30 metric tons of L-malic acid per month in a continuous process with a 1,000 L column fed at a flow rate of 450 L.h-1 of 1 M sodium fumarate solution.
Genetic engineering has been used to improve productivity, by which S. cerevisiae is modified to overexpress fumarase.
With this method, a conversion rate of 65 mmol.g-1.h -1 has been observed.
Another possibility is the cultivation of an L-malic acid forming microorganism (e.g. Aspergillus flavus or Schizophyllum commune).
The best results have been achieved by cultivation of A. flavus on glucose.Afinal product concentration of 113 g.L-1 with a yield of 1.26 mol of malic acid per mole of glucose and a productivity of 0.59 g.L-1.h-1 has been measured.
Moreover, new biotechnological routes have been described using metabolically engineered S. cereviciae.
In batch cultivations, concentrations up to 59 g.L-1 with a yield of 0.42 mol of malic acid per mole of glucose and a productivity of 0.19 g.L-1.h-1 have been observed.
Biochem/physiol Actions
Malic acid is a dicarboxylic acid and an important regulatory metabolite.
Malic acid has been implicated in process of fruit ripening.
Malic acid is important for the starch metabolism; low malic acid content results in transient accumulation of starch.
Mitochondrial-malate metabolism modulates ADP-glucose pyrophosphorylase activity and redox status of plastids.
