Citric Acid : Structure, Properties, Uses, Benefits, Side Effects

Citric acid is one of the chemical compounds that is found in citrus fruits. The sour taste of citrus fruits like oranges and lemons is because of the presence of citric acid by 8% of its total dry weight. As citric acid has many benefits, it is used in many medicines, beverages, disinfectants, and skincare products. In this section, you will learn more about what is citric acid and the uses of citric acid in food.

What Is Citric Acid?

Citric Acid is a poor organic acid but a strong organic compound. It is generally found in citrus fruits. This acid is usually found in fruits and vegetables such as oranges, tomatoes, lemons, pomelo, etc.

As per biochemistry, the answer what is citric acid; it is a crucial compound because it works as an intermediate in the citric acid cycle. As a result, it occurs in the digestion of almost all living things. It also works as an environmentally friendly antioxidant and cleaning agent.

History of Citric Acid

In the eighth century, citric acid was first discovered by Islamic conjurer Jabir Ibn Hayyan. But the credit for obscuring it was gone to chemist Carl Wilhelm Scheele. In 1784, citric acid was first obscured by Carl. In 1822, Carl isolated citric acid for the first time from lemon juice. He established its chemical composition. Based on the Italian citrus fruit industry, industrial-level citric acid production began in 1860. In some ways, citric acid is similar to table salt. Previously, in the market, it was known as sour salt.

Citric Acid Structure

Citric acid is also termed tribasic acid and exists in two forms, i.e., anhydrous citric acid and monohydrate citric acid. But the chemical name and citric acid structure remain the same in both forms.

The chemical formula of citric acid is C₆H₈O₇. It can be described as a tricarboxylic acid. Its IUPAC name is 2-hydroxypropane-1,2,3-tricarboxylic acid. Citric acid is also known as tribasic acid.

The citric acid structure is given below:

Citric Acid Preparation

Citric acid is exclusively produced by fermentation with the filamentous fungus Aspergillus niger. Industrial production uses carbohydrates or agro-industrial residues as substrates by three processes: submerged, surface, and solid fermentations. Industrially, sucrose is used to manufacture citric acid. When the resulting solution is filtered from the mould, citric acid is separated by reacting it with calcium hydroxide (lime) to yield salt of calcium citrate salt. Citric acid is restored by treatment with sulfuric acid from the calcium citrate salt produced formerly. Sometimes, citric acid is outlined from the fermentation broth. It is separated by using an extraction process. A hydrocarbon-based solution isolates citric acid from the organic base trilaurylamine. After this, re-extraction from the organic solution by water takes place.

Citric Acid Properties

Some properties of citric acid are

1. It is a weak organic acid.
2. The molecular formula of citric acid is C₆H₈O₇.
3. It is a colourless, odourless, and tasteless crystalline compound.
4. The structure of citric acid crystals is monoclinic.
5. The molar mass of citric acid is 192.124g/mol.
6. Its density is 1.665g/cm3.
7. The boiling point of citric acid is 310°C, while its melting point is 153°C.
8. Other than water, it is soluble in ether, alcohol, and acetone.
9. At room temperature, it exists in the white crystalline powder form.
10. On heating above 175°C, it decomposes through carbon dioxide and water loss. C₆H₈O₇ + heat → CO₂ + H₂O

Uses of Citric Acid

Citric acid is easily available in many vegetables and fruits naturally. Because of its properties, it has many uses. Some of them are

1. The use of citric acid in food and beverages is very common. It gives a citrus taste to the food items and enhances their flavour.
2. It lowers the pH and makes the oxidative enzymes lethargic in frozen foods. As a result, citric acid in food prevents the growth of bacteria and later spoils it.
3. It is used to produce detergents and soaps and soften acidic water.
4. Because of its pH-balancing behaviour, citric acid is used in many cosmetic products.
5. It helps calcium get chelated in your blood due to its anticoagulating nature.
6. It helps supply calcium and vitamin C to the body and, thus, assists in bone maintenance.
7. Enhancing antioxidant properties help improve health from diseases such as osteoporosis, bone health, etc.
8. It is a good preservative for blood and hence, widely used in the pharmaceutical industry.
9. Due to its emulsifying character, citric acid in food and ice cream companies is used widely. It keeps the fat globules from making the ice cream too creamy and tasty.
10. For sucrose crystallisation, citric acid is used in caramel.

Citric Acid Benefits

There are many gains in using citric acid. It can benefit you in many ways.

1. Citric acid benefits as a powder:

It exists in white crystalline powder form at room temperature. It can improve your health and your kidney and throat infections. It can even help you to get rid of acne. Some other citric acid benefits as a powder are

• As a food preservative and flavouring agent. You can consider it citric acid in food.
• It is used in making sour candies.
• It is also used as an emulsifier by many ice cream companies.

2. Citric acid benefits as a cleansing agent:

It can aid in softening the water, in soaps and detergents, sanitisers, and in many other ways as a cleansing agent.

• Its products are considered chelating agents.
• Citric acid benefits in the kitchen and bathroom.
• It can also be used as a deodorant.

3. Citric acid benefits in cosmetics:

It is a poor organic acid and can be helpful with many cosmetic items. Some of its uses are

• It can help as a home mask in removing dead skin.
• It can brighten your skin tone and diminish wrinkles and skin scars.
• It is used for balancing the pH levels and in many beauty products.
• It is used in body wash, cleansers, face chemicals, nail cleaners, 
• and shampoos.

4. Citric acid benefits in water treatment:

• It aids in softening the acid properties of water because of its chelating and buffering characteristics.
• It extracts organic acid from the water, making it a reliable conditioner.
• It can separate metal from the water, making it suitable for water treatment.

5. Citric acid benefits in industrial uses:

• It is used in electroplating, soap and detergent manufacturing, and leather tanning.
• It assists in food preservation and pharmaceutical and cosmetic manufacturing.
• It is also useful in the polymer industry and has many other commercial uses.

Side Effects of Citric Acid

Though citric acid is good for health, excessive exposure can cause an acidic stomach, tooth decay, muscle twitching, numbness, or cramps. Some other side effects of citric acid are

• A long touch of citric acid on the skin can cause irritation, swelling, hives, and other problems.
• It can affect your heart rate and mood changes.
• If it enters your eyes, it can burn them.
• You can feel nausea or vomiting if you take medicines containing citric acid by mouth.
• Some side effects of citric acid are diarrhoea, convulsions, chest pain, lightheadedness, fatigue, confusion, etc.

Conclusion

Citric acid naturally occurs in all citrus fruits. Not only in citrus fruits, but it is also found in all plants and animals in traces. Many other products also include citric acid. But these things contain citric acid versions that are manufactured or artificial, not natural. Citric acid is not an antioxidant in itself, but it enhances this property in many food items. It is very beneficial in various ways. But overusing it also has some side effects. So, it is better to take some precautions.

Frequently Asked Questions

1. Can citric acid be used as a disinfectant?

A. Yes. It is used as a disinfectant. It can kill mould, bacteria, and mildew. In this way, it helps sanitise, clean, and generally disinfect. It is also helpful in removing soap scum, hard water stains, lime, calcium deposits, and rust. Citric acid is also employed as a preservative.

2. Is citric acid bad for your teeth?

A. Excessive amounts of citric acid may cause tooth enamel to dissolve over time. Citrus contains a high quantity of acid, slowly eroding your enamel. The yellow dentin beneath shows through as enamel gets withered, and you can thrive in decay and cavities. However, do not avoid citrus as it is beneficial for the body. But control the amount of citrus intake.

3. In what ways can we prevent teeth from getting affected by citric acid?

A. Some ways can help you prevent your teeth from the effects of citric acid.

• After consuming any food item or beverage containing citric acid, rinse your mouth properly.
• Make use of a straw while drinking citric acid-containing beverages.