Citric acid is a weak organic acid with the molecular formula of C₆H₈O₇. It is colorless, odorless, and has a sour acidic taste. It was first isolated in 1784 and commercial production began by 1890. It is an intermediate compound in the metabolism of all aerobic organisms. Since it is an organic acid, it is used in food manufacturing industries as a flavoring agent, preservative, and emulsifier. In this article, we discuss the 40 uses of citric acid in various industries like food processing, cleaning, cosmetics, medicine, etc.
Citric acid is used as a chelating agent as it forms complexes with metal cations. It is useful in improving soap and detergents and removing heavy metals from soil. It is also used as an emulsifier in creams, jells, and liquids. It is used as a buffer to increase solubility. It is a vital component of bone. Citric acid derivatives in our bodies regulate many biological functions.
Uses of citric acid in the Food processing industry
In the food processing industry, citric acid is mainly used as an acidity regulator, preservative, and flavoring agent. Since it is mildly acetic with a slightly sour taste with good biocompatibility, it is widely preferred to be used in food industry.
- Citric acid is added to processed and packaged foods as a preservative.
- It is used as a sour flavoring agent in many drinks, including ice cream, sorbets, sodas, and wine.
- Citric acid is added to many canned and jarred foods to help prevent food poisoning.
- Citric acid derivatives are used as natural emulsifiers in dairy products.
- Citric acid is found naturally in lemons, limes, pineapples, grapefruits, and berries, but not in blueberries, tomatoes, broccoli, carrots, and a few varieties of peppers.
Uses of citric acid in cosmetics and personal care products
- Citric acid and its derivatives are used as ingredients for personal care products like deodorants, body sprays, etc.
- Citric acid helps to brighten skin and is used in chemical skin peels.
- Citric acid is also used in cosmetic products used near the eye, lips, nose, or mouth. Since it is an organic acid, it is preferred for such applications compared to other chemicals.
- Citric acid derivative sodium citrate is used in lipsticks.
- Citric acid due to its chelating ability, is used in the manufacture of soaps.
- Citric acid helps increase the life of cosmetic products. It is used as a cross-linking agent in many gel formulations.
- Citric acid is used as a pH regulator for cosmetic formulations as our skin is pH sensitive. Skincare products are generally acidic to avoid any microbial infections.
Uses of citric acid in Cleaning products
- Citric acid is a formulation to remove hard water buildup on utensils.
- Citric acid can also be used as a deodorizer in cleaning formulations.
- It can be used as a mild cleaning agent for coffee and tea stains and even for removing urine stains in washrooms.
Uses of citric acid in medicine
- Citric acid due to its mild acidity, helps kill harmful bacteria. It is used in treat skin infections.
- Citric acid is combined with sodium citrate and potassium citrate to lower acid levels in the urine to help prevent gout.
- Citric acid derivative sodium citrate is used in prevent clotting during storage.
- Food supplements contain citric acid as a stabilizing agent.
What are the uses of citric acid in our homes?
- A sprinkling of lemon juice, which contains) citric acid over fruits like apples can help prevent them from turning brown.
- A citric acid solution is used as a mild cleaning agent. Lemon is commonly used to treat utensils that are difficult to clean with plain water.
- Citric acid is added to fruit juices as a flavoring agent to add sourness to the taste.
- Citric acids can be used in shampoo formulations to remove wax.
Other uses of citric acids
Citric acid has been under production for two centuries. But still many research groups are working on its various novel applications. The uses stated below are mostly in their research stage and will be commercial in the coming years.
- Citric acid is used as a catalyst for many chemical reactions. It has been used to catalyze the hydrothermal carbonization of cellulose nanofibers. You can read this article to learn more. Citric acid is used as a catalyst in environmentally friendly chemical synthesis. Other catalysts are generally hazardous to the environment.
- Citric acid is used in many chemical reactions as a stabilizing agent. It is very difficult to generate specific nanostructures and porosity during chemical reactions. Citric acid is able to stabilize such structures during synthesis. You can read this article for more details.
- Citric acid metabolism in fruits is an important factor in their storage quality. Citric acid is known to influence the taste and flavor of the fruit. High temperatures might cause citric acid degradation in fruits. This article titled “Effects of hot air treatment and chitosan coating on citric acid metabolism in ponkan fruit during cold storage.” explains the influence of temperature on citric acid contained in fruit which indirectly affects the fruit quality.
- Citric acid is used as a biodegradable chelating agent for soil decontamination applications. It is a good choice for removing metals from contaminated soils as it won’t cause any major environmental issues. It can remove metals like zinc, copper, and other heavy metals.
- Citric acid is used in stabilizing minerals during the fortification of milk and other formulations.
- Citric acid along with ethanol is shown to increase the longevity in cut flowers. Read more in this article.
- Citric acid has been shown to improve the drought tolerance and water status in bean plants. [DOI:https://doi.org/10.5073/JABFQ.2013.086.029]
- Citric acid has been used for the recovery of cobalt and nickel from lithium-ion batteries.[DOI 10.1051/e3sconf/20186703008] Lithium-ion batteries are nowadays the industry standard. They are rechargeable and contain metals like cobalt and nickel which can cause serious environmental issues. So, it is important to treat the batteries before discarding them.
- Citric acid can be used to modify or functionalize surfaces to improve the efficiency of adsorbents.[DOI 10.3389/fmats.2019.00005]
- Citric acid can be used as a binder for wood. You can read this review article titled “A Review on Citric Acid as Green Modifying Agent and Binder for Wood” for more details.
- Citric acid is used as a stabilizing agent in many hydrothermal synthesis procedures. Novel nanostructures are made possible by specific stabilizing agents. In this article citric acid has been investigated for the hydrothermal synthesis of Bi2MoO6 nanoplates.
- Citric acid is used in the crosslinking of Agar/fish gelatin films. They may be used for packaging or pharmaceutical applications in the future.
- Citric acid can be used in the treatment of coal ash. Heavy metals present in the coal ash can be leached by citric acid treatment.
- Citric acid can be used in the demineralization of the exoskeleton of shrimps.
- Citric acid treatment to peace has been shown to reduce post-harvest decay.
- Citric acid is used as a water softening agent because of its chelating ability.
