by Introduction to Fumaric Acid
Fumaric acid is an organic acid that occurs naturally in certain plants and is also produced industrially. It is a white, crystalline powder that is sparingly soluble in water and highly soluble in hot water. Its chemical formula is HO2CCH=CHCO2H. In this article, we will discuss the various properties and applications of this important organic compound.
Chemical Properties of Fumaric Acid
Fumaric Acid is an unsaturated dicarboxylic acid that contains a double bond between the second and third carbon atoms. The two carboxyl groups make it highly acidic in nature. Its pKa values are 3.03 and 4.44. When dissolved in water, it forms fumarate salts and releasing H+ ions. Due to the presence of the carbon double bond, it undergoes addition reactions readily. It can react with bromine, hydrogen halides and many other electrophilic additions based on alkene chemistry. Its reactivity arises from the presence of carboxyl groups and alkene functionality.
Natural Sources of Fumaric Acid
Fumaric acid occurs naturally in certain plants especially in lichen species such as Iceland moss (Cetraria islandica) and fumitory (Fumaria officinalis). It is found in concentrated amounts in a plant known as fumitory, from which it derives its name. Other natural sources include figs, honey fungus and oak-mushrooms. It is also produced commercially by fermentation using filamentous fungi such as Rhizopus species. These microorganisms are grown under controlled conditions in large fermenters to yield high concentrations of fumaric acid.
Uses and Applications
One of the major uses of fumaric acid is in food products mainly as an acidulant. It has a much milder taste compared to other acids and thus finds application in various foods, beverages and desserts for flavoring and acidity regulation. It also has applications in animal feed as a preservative. In chemicals industry, it is used to produce resins, alkyd resins and polyester resins. It also acts as a raw material to manufacture fumarates, maleates and other industrially useful chemical compounds. Fumaric acid finds use in pharmaceutical industry to make sustained release tablets, as it can dissolve rapidly when the tablets reach target location in intestines. It is also used in production of certain plastics, polyurethanes, candles and chewing gums.
Malic Acid vs Fumaric Acid
Malic acid and fumaric acid are two important dicarboxylic acids used commonly in food and chemical industries. While malic acid has two hydroxyl functional groups and is found abundantly in fruits, fumaric acid contains a double bond instead and occurs in certain lichens and fungi. Malic acid imparts a very sharp, tart and fruity taste whereas fumaric acid has a relatively milder taste. Both acids have great buffering capacity and act as preservatives but fumaric acid is preferred over malic acid in certain applications due to its less harsh flavor profile. Malic acid is used commonly in wines and candy making whereas fumaric acid finds wider applications in bakery, meat and dairy products for taste and acidity control.
Uses in Cosmetics and Pharmaceuticals
Apart from foods and chemicals, fumaric acid also finds applications in cosmetics and pharmaceuticals due to its unique properties. In skin care products, it acts as an exfoliating agent due to its hydroxyl and carboxyl groups. It helps in removal of dead skin cells and rejuvenating the skin. Fumaric acid acts as a moisturizer as well due to humectant effects. In pharmaceuticals, it is used as an active drug called fumarates in treatment of psoriasis and other skin diseases like lichen planus. It suppresses the immune system and reduces excess production of skin cells. Fumarates work by affecting certain cells and processes that play a role in psoriasis. Thus fumaric acid is a multifaceted acid with applications across industries.
Safety Profile
Fumaric acid is generally recognized as safe for intended uses in food products at appropriate levels. The acceptable daily intake is not specified but a level of 5 mg per kg body weight is considered safe. Long term ingestion above this level may lead to diarrhea and stomach upsets due to its acidic nature. Occupational exposure to high levels can cause irritation to eyes and respiratory tract. It is classified by EPA in U.S. as generally of low concern for both human health and environment. However standard safety precautions must be followed while handling concentrated forms. The literature reveals no carcinogenic, mutagenic or toxic effects when used judiciously in various applications. Proper ventilation should be ensured in its industrial production facilities.
Concluding Remarks
In summary, fumaric acid is a versatile unsaturated dicarboxylic acid found in nature as well as produced commercially. It possesses carboxyl groups and alkene functionality leading to characteristic chemical reactivity and broad applications. Key properties like acidity, buffering action and mild taste makes it preferable for use as acidulant and preservative in foods and animal feeds. It also serves as a crucial building block chemical for resins, plastics and pharmaceuticals. Fumaric acid supplements the natural organic acids portfolio and exemplifies an important product of fermentation biotechnology.
