You’ve heard a lot about organic acids. As a matter of fact, we’ve all learnt about a few of the organic acids in school in our science(chemistry) classes. Well, what are organic acids? In simple terms, organic acids are organic compounds with acidic properties. They are usually characterized by weak acidic attributes and do not dissociate completely in the presence of water. Carboxylic acids are the most common organic acids whose acidity is linked with their carboxyl group – COOH. This article discusses the list of important organic acids, their characteristics, uses etc.
Sulfonic acids, containing the group –SO2OH, are more or less stronger acids. Alcohols, with the group –OH, can act as acids but they are generally very weak. The comparative stability of the conjugate base of the acid determines its acidity. Similarly, other groups also confer acidity, usually of a weak context: the thiol group –SH, the enol group, and the phenol group. In biological terms, organic compounds containing these specific groups are generally referred to as organic acids.
Widely distributed in nature, organic acids occur in animals, plants, and microbial sources. They contain one or more carboxylic acid groups, which are linked covalently in groups such as amides, esters, and peptides. Production of organic acids on a large industrial scale is mainly confined to acids of microbial origin. A number of organic acids belonging to bacterial and fungal origin are essential industrial products, the biological production of which has a concrete economic advantage, however, over chemical synthesis.
List of Important Organic Acids
A few common examples of the important organic acids are listed hereunder.
- Lactic acid
- Acetic acid
- Formic acid
- Citric acid
- Malic acid
- Oxalic acid
- Uric acid
- Tartaric acid
- Ascorbic acid
Lactic Acid
The first acid in the list of important organic acids is lactic acid. Lactic acids are considered lower molecular mass organic acids that are miscible in water. The molecular formula of lactic acid is CH3CH(OH)COOH. In the solid state, it is white in colour and when dissolved it forms a colourless solution. Lactate is normally the conjugate base of lactic acid. It is a byproduct of anaerobic respiration- a process where the cells produce energy without the presence of oxygen around. Bacterias produces lactic acid in yoghurt, buttermilk, kefir etc and also in our gut. This acid is also found in our blood where it is usually deposited by the red blood cells and muscle.
Lactic acid-producing bacteria are generally divided into two categories: homofermentative bacteria like Lactobacillus casei and Lactococcus lactis, which produces two moles of lactate from one mole of glucose, and secondly the heterofermentative species which produces one mole of lactate from one mole of glucose as well as carbon dioxide and acetic acid or ethanol.
Many species of bacteria that respire anaerobically, generate lactic acid as a waste product. As a matter of fact, these little species make up between 0.01-1.8% of the human gut, as per a review published in the Journal of Applied Microbiology. The more these little guys feed on sugar, the more lactic acid they produce.
Relatively more insidious are those lactic acid bacteria that live inside our mouths. Due to the acidifying effect, they have on our saliva, these lactic acid bacteria are bad news for tooth enamel. Additionally, our body produces lactic acid when it is low in oxygen level and therefore it needs to convert glucose into energy. Generally, Lactic acid buildup can lead to muscle pain, cramps, and muscular fatigue.
Acetic Acid
The second acid from the list of important organic acids is acetic acid. The most important member of carboxylic acid, acetic acid, is a colourless liquid that is acidic in nature as well as an organic compound. Having the chemical formula CH3COOH, it is also known as ethanoic acid. Acetic Acid is a simple synthetic carboxylic acid with antifungal and antibacterial properties. While its mechanism of action is not completely known, undissociated acetic acid may intensify lipid solubility resulting in increased fatty acid accumulation on the cell membrane or in other cell wall structures. A weak acid, Acetic acid can inhibit carbohydrate metabolism following the subsequent death of the organism.
Acetic acid is the conjugate acid of an acetate that contains two carbons. It serves the role of a protic solvent, an antimicrobial food preservative, a food acidity regulator, and a Daphnia Magna metabolite. Derived from natural gas, acetic acid is a major commodity chemical. Acetic acid, when diluted by fermentation and oxidation of natural carbohydrates is called vinegar. Apart from water, the main component of vinegar is acetic acid.
Acetate is a salt or ester of acetic acid which contains the anion CH3COO− or the group —OOCCH3.
Formic Acid
Systematically known as Methanoic acid, formic acid is considered the simplest carboxylic acid. Its chemical formula is CH2O2 or HCOOH. It is found naturally, in the stings and bites of many insects, including bees and ants. Formic acid is generally a fuming colourless liquid that has a pungent, penetrating odour at room temperature, comparable to acetic acid. It irritates the mucous membrane and results in blisters of the skin. It is miscible with water and most polar organic solvents and is rather soluble in hydrocarbons.
Formic acids are used in the processing of textiles and leather. Formic acid was initially isolated from ants and hence named after the Latin word Formica, which means ants.
Citric Acid
An organic acid, citric acid is naturally found in citrus fruits like lime, lemon, orange etc. Its chemical formula is HOC(CH₂CO₂H)₂ and it is considered a weak organic acid. It is a white solid tricarboxylic acid. This acid was first isolated from lemon juice by a Swedish researcher in the year 1784.
Due to its acidic, sour tasting properties, citric acid is widely used as a flavouring and preserving agent in commercial products like candies, soft drinks etc. It is also used as a stabilizer as well as a preservative in medicines and as a disinfectant against bacteria and viruses.
The word citric originates from the Latin word Citrus. Natural sources of citric acid are found in fruits like lemons, lime, tangerine, grapefruit etc. It is also found in lesser amounts in fruits like strawberry, pineapple, raspberry, cherry etc.
Malic Acid
An organic compound, Malic acid, is a dicarboxylic acid that is made by all living species. The chemical formula of Malic acid is C₄H₆O₅ and it has a sour taste. Moreover, Malic acid is also a chemical that is found in a couple of fruits and wines. Sometimes it is used as a medicine too.
Malic acid is most commonly used for dry mouth, a condition where the salivary glands do not produce enough saliva. It is also used for skin conditions, fibromyalgia, fatigue etc. In foods generally, malic acid is used as a flavouring agent to give a tart taste to the food. Malic acid is widely used in the manufacturing of cosmetics to adjust the acidity of cosmetics.
Oxalic Acid
Generally found in plants, oxalic acid is the simplest dicarboxylic acid with the chemical formula HO 2C−CO 2H. It is a white crystalline in the solid state and when dissolved in water it is a colourless solution. Oxalic acid is normally found in plants like fruits, leafy green vegetables, spinach, cocoa, seeds, beet greens, star fruit, endive etc. When oxalic acid mixes with other minerals, it results in the formation of oxalates.
Oxalic acid is also known by the name ethanedioic acid. This acid is widely used as an acid rinse in laundries, where it is effective in removing rust and ink stains. It is, however, the chief constituent of many commercial preparations used for getting rid of scale from automobile radiators.
Uric Acid
A heterocyclic compound of carbon, hydrogen, oxygen, nitrogen and oxygen, Uric acid has the formula C₅H₄N₄O₃. It produces ions and salts known as urates and acid urates, like ammonium acid urate. Uric acid is a normal component of urine. It is a waste product found in human blood.
Uric acid is generally, a chemical produced when the human body breaks down substances called purines. However, Purines are normally produced in the body and are also usually found in some foods and drinks.
Tartaric Acid
Tartaric acid is an organic acid that is white in colour and crystalline. It is mostly found in plants, especially in grapes, bananas and tamarind. It is a dicarboxylic acid with a chemical formula C4H6O6.
Tartaric acid has a relatively stronger, sharper taste than citric acid. Although it is renowned for its natural occurrence in grapes, it also occurs in papaya, apples, cherries, peach, pear, strawberries, pineapple, mangos, and citrus fruits. Tartaric acid is used preferentially in foods containing grapes or cranberries, primarily wines, jellies, and confectioneries. Commercially, tartaric acid is made from the waste products of the wine industry and is more high-priced than most acidulants, including malic and citric acids.
Ascorbic Acid
Also known popularly as Vitamin C, ascorbic acid is usually found in a variety of foods and also used as a dietary supplement. It is used for the treatment and prevention of scurvy as well as to treat people with low levels of vitamin C, who does not receive an adequate amount of vitamin C from their food intake.
We hope this article about the list of important organic acids has helped you in getting a clear idea about the various organic acids, their properties and their uses. You can also check out our vast collection of GK blogs from the Entri App. Happy learning Knowledge Seekers!!
