DL-MALIC ACID

DL-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. 
DL-malic acid has a role as a food acidity regulator and a fundamental metabolite. 
DL-malic acid is a 2-hydroxydicarboxylic acid and a C4-dicarboxylic acid. 

CAS:    617-48-1
MF:    C4H6O5
MW:    134.09
EINECS:    210-514-9

Synonyms
(+/-)-2-HYDROXYSUCCINIC ACID;MALIC ACID, DL-;(+/-)-butanedioicaci;Musashi-no-Ringosan;DL-Malic acid, 98% (DL-felsre);C00711;(+/-)-HYDROXYBUTANEDIOIC ACID;(+/-)-HYDROXYSUCCINIC ACID

DL-malic acid is functionally related to a succinic acid. 
DL-malic acid is a conjugate acid of a malate(2-) and a malate.
White or nearly white, crystalline powder or granules having a strongly acid taste. 
One g dissolves in 0.8 mL of water and in 1.4 mL of alcohol. 
DL-malic acid's solutions are optically inactive. 
DL-malic acid melts at about 130°.
DL-malic acid is an organic compound with the molecular formula HO2CCH(OH)CH2CO2H. 
DL-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. 
DL-malic acid has two stereoisomeric forms (L- and D-enantiomers), though only the L-isomer exists naturally. 

The salts and esters of DL-malic acid are known as malates. 
The malate anion is a metabolic intermediate in the citric acid cycle.
DL-malic acid is an alpha hydroxy acid found in certain fruits and wines. 
DL-malic acid's used in foods and cosmetics, and sometimes as medicine. 
DL-malic acid is sour and acidic. 
This helps to clear away dead skin cells when applied to the skin. 
DL-malic acids sourness also helps to make more saliva in people with dry mouth. 
DL-malic acid is also involved in the Krebs cycle. 
DL-malic acid is a process the body uses to make energy. 
People commonly use malic acid for dry mouth. 
DL-malic acid is also used for acne, fibromyalgia, fatigue, wrinkled skin, and many other conditions, but there is no good scientific evidence to support these uses. 
DL-malic acid is an alpha hydroxy acid. 
Don't confuse DL-malic acid with other alpha hydroxy acids (AHAs).

DL-malic acid is a versatile organic compound that plays a significant role in various industries, particularly in food and beverage, pharmaceuticals, and cosmetics. 
Known for its natural occurrence in fruits, particularly apples, DL-malic acid is widely recognized for its sour flavor profile, making it an excellent acidulant in food formulations. 
DL-malic acid's ability to enhance flavor and preserve freshness makes it a preferred choice among food manufacturers. 
Additionally, DL-malic acid serves as a key ingredient in the production of biodegradable polymers and as a pH regulator in cosmetic formulations, contributing to skin hydration and texture improvement.
In the pharmaceutical sector, DL-malic acid is utilized as an excipient in drug formulations, enhancing solubility and stability. 
Its chelating properties also make DL-malic acid valuable in metal ion sequestration applications. Researchers appreciate DL-Malic acid for its role in metabolic studies and its potential in developing new therapeutic agents. 
With its multifunctional applications and natural origins, DL-Malic acid stands out as a compound that meets the diverse needs of various industries while promoting sustainability.
DL-malic acid is a synthetic version of malic acid that contains equal parts of both D- and L-isomers. 

This racemic mixture is produced via chemical synthesis and is widely used in the food and supplement industries due to its cost-effectiveness and wide functionality.
While only the L-isomer contributes to human metabolism, DL-malic acid is still accepted in food and supplement manufacturing because it performs similarly in taste and formulation properties. 
DL-malic acid’s commonly used as a food acidulant, flavor enhancer, and pre-workout supplement ingredient due to its role in energy production.
Malic acid is a dicarboxylic acid with the chemical formula C4H6O5, which has two structures known as enantiomers. 
DL-malic acid occurs naturally in all organisms, while D-malic acid must be synthesized in the laboratory.
A mixture of DL-malic acid and L-malic acid is called a racemic mixture, which is commonly known as DL-malic acid.

DL-Malic acid Chemical Properties
Melting point: 131-133 °C(lit.)
Boiling point: 150℃[at 101 325 Pa]
density: 1,609 g/cm3
vapor density: 4.6 (vs air)
vapor pressure: <0.1 mm Hg ( 20 °C)
FEMA: 2655 | L-MALIC ACID
Fp: 203°C
storage temp.: Refrigerator
solubility methanol: 0.1 g/mL, clear, colorless
pka: pK1:3.458;pK2:5.097 (25°C)
form: Solid
color: White to Off-White
Water Solubility: 500g/L at 25℃
Stability: Stable. Incompatible with strong oxidizing agents, strong bases, amines, alkali metals, carbonates.
LogP: -1.3 at 24℃
CAS DataBase Reference: 617-48-1(CAS DataBase Reference)
EPA Substance Registry System: DL-malic acid(617-48-1)

Biochemistry
DL-malic acid is the naturally occurring form, whereas a mixture of L- and D-malic acid is produced synthetically.
Malate plays an important role in biochemistry. 
In the C4 carbon fixation process, malate is a source of CO2 in the Calvin cycle. 
In the citric acid cycle, (S)-malate is an intermediate, formed by the addition of an -OH group on the si face of fumarate. 
DL-malic acid can also be formed from pyruvate via anaplerotic reactions.
Malate is also synthesized by the carboxylation of phosphoenolpyruvate in the guard cells of plant leaves. 
Malate, as a double anion, often accompanies potassium cations during the uptake of solutes into the guard cells in order to maintain electrical balance in the cell. 
The accumulation of these solutes within the guard cell decreases the solute potential, allowing water to enter the cell and promote aperture of the stomata.

Uses    
DL-malic acid is primarily used in the food and beverage industry.
DL-Malic acid is used as a food additive. 
DL-malic acid is a component of some artificial vinegar flavors. 
Further, DL-malic acid is used in the preparation of chiral compounds, including κ-opioid rece. 
DL-malic acid is utilized for chiral resolution by ligand-exchange capillary electrophoresis.
The uses of DL-malic acid generally relate to the role of malic acid in the production of chemical energy for both aerobic and anaerobic conditions. 
These uses include the management of discomfort, energy production, oral hygiene, and general detoxification.

Oral Hygiene Support
DL-malic acid may have antiseptic properties that make it useful for maintaining oral hygiene.

Energy Support
DL-malic acid may help to maintain normal energy levels, especially for chronic conditions characterized by fatigue.

Detoxification
DL-malic acid can bind metal ions such as aluminum and lead. 
This effect can help to support general health, especially for the brain and liver.

Discomfort Management
DL-malic acid may help to manage muscular discomfort due to chronic conditions. 
This use is most applicable for conditions characterized by low oxygen levels.

In food
DL-malic acid was first isolated from apple juice by Carl Wilhelm Scheele in 1785.
Antoine Lavoisier in 1787 proposed the name acide malique, which is derived from the Latin word for apple, mālum—as is its genus name Malus.
In German DL-malic acid is named Äpfelsäure (or Apfelsäure) after plural or singular of a sour thing from the apple fruit, but the salt(s) are called Malat(e). 
DL-malic acid is the main acid in many fruits, including apricots, blackberries, blueberries, cherries, grapes, mirabelles, peaches, pears, plums, and quince, and is present in lower concentrations in other fruits, such as citrus. 
DL-malic acid contributes to the sourness of unripe apples. 
Sour apples contain high proportions of the acid. 
DL-malic acid is present in grapes and in most wines with concentrations sometimes as high as 5 g/L.
DL-malic acid confers a tart taste to wine; the amount decreases with increasing fruit ripeness. 
The taste of DL-malic acid is very clear and pure in rhubarb, a plant for which it is the primary flavor. 
DL-malic acid is also the compound responsible for the tart flavor of sumac spice. 
DL-malic acid is also a component of some artificial vinegar flavors, such as "salt and vinegar" flavored potato chips.

The process of malolactic fermentation converts DL-malic acid to much milder lactic acid. 
DL-malic acid occurs naturally in all fruits and many vegetables, and is generated in fruit metabolism.
DL-malic acid, when added to food products, is denoted by E number E296. 
DL-malic acid is sometimes used with or in place of the less sour citric acid in sour sweets. 
These sweets are sometimes labeled with a warning stating that excessive consumption can cause irritation of the mouth. 
DL-malic acid is approved for use as a food additive in the EU, US and Australia and New Zealand (where it is listed by its INS number 296).
DL-malic acid contains 10 kJ (2.39 kilocalories) of energy per gram.

Production and main reactions
Racemic DL-malic acid is produced industrially by the double hydration of maleic anhydride. 
In 2000, American production capacity was 5,000 tons per year. 
The enantiomers may be separated by chiral resolution of the racemic mixture. 
S-Malic acid is obtained by fermentation of fumaric acid.
Self-condensation of malic acid in the presence of fuming sulfuric acid gives the pyrone coumalic acid:

2 HO2CCH(OH)CH2CO2H → HO2CC4H3O2 + 2 CO + 4 H2O
Carbon monoxide and water are liberated during this reaction.
DL-malic acid was important in the discovery of the Walden inversion and the Walden cycle, in which (−)-malic acid first is converted into (+)-chlorosuccinic acid by action of phosphorus pentachloride. 
Wet silver oxide then converts the chlorine compound to (+)-malic acid, which then reacts with PCl5 to the (−)-chlorosuccinic acid. 
The cycle is completed when silver oxide takes this compound back to (−)-malic acid.
DL-malic acid is used to resolve α-phenylethylamine, a versatile resolving agent in its own right.