Citric acid is a naturally occurring organic acid found in various fruits particularly citrus fruits like lemons oranges and limes. It is widely used in the food pharmaceutical and cosmetic industries due to its acidity and preservative properties.
In this topic we will discuss the chemical formula of citric acid its structure properties uses and significance in various industries.
Chemical Formula of Citric Acid
The chemical formula of citric acid is C₆H₈O₇. This formula indicates that each molecule of citric acid consists of:
- 6 Carbon (C) atoms
- 8 Hydrogen (H) atoms
- 7 Oxygen (O) atoms
Citric acid is classified as a tricarboxylic acid because it contains three carboxyl (-COOH) functional groups. This makes it a key component in biological and industrial processes.
Molecular Structure of Citric Acid
Citric acid has a branched structure consisting of:
- A central carbon chain
- Three carboxyl (-COOH) groups
- One hydroxyl (-OH) group
The structural formula of citric acid is:
This arrangement makes citric acid highly soluble in water and gives it strong acidic properties.
Physical and Chemical Properties of Citric Acid
1. Physical Properties
- Molecular Formula: C₆H₈O₇
- Molar Mass: 192.12 g/mol
- Appearance: White crystalline powder
- Taste: Sour and acidic
- Solubility: Highly soluble in water
- Melting Point: 153°C (307°F)
2. Chemical Properties
- Acidic Nature: Citric acid is a weak organic acid that can donate protons (H⁺).
- Buffering Agent: It helps regulate pH in various solutions.
- Chelating Agent: It binds with metal ions preventing oxidation and discoloration in food and cosmetics.
- Decomposition: When heated citric acid decomposes into carbon dioxide (CO₂) and water (H₂O).
Sources of Citric Acid
Citric acid occurs naturally in many fruits and vegetables with the highest concentrations found in:
- Lemons
- Limes
- Oranges
- Grapefruits
- Berries
Industrially citric acid is produced through fermentation of sugars using the fungus Aspergillus niger. This method is cost-effective and provides a high yield of citric acid for commercial use.
Uses of Citric Acid
1. Food and Beverage Industry
Citric acid is one of the most widely used food additives serving as:
- A flavor enhancer in soft drinks and candies.
- A preservative to extend shelf life.
- A pH regulator in canned foods and dairy products.
2. Pharmaceutical Industry
- Used in effervescent tablets like vitamin C supplements.
- Acts as a stabilizer in medications.
- Enhances the absorption of minerals like calcium and magnesium.
3. Cleaning Products
- Found in detergents and dishwashing liquids due to its ability to dissolve limescale.
- Works as a natural disinfectant against bacteria and mold.
4. Cosmetics and Personal Care
- Used in skincare products as an exfoliating agent.
- Found in shampoos and conditioners to adjust pH and enhance hair texture.
5. Industrial Applications
- Used in water treatment plants to remove metal impurities.
- Acts as a rust remover in cleaning solutions.
- Employed in biodegradable plastics production.
Citric Acid in Biological Systems
1. Role in the Krebs Cycle (Citric Acid Cycle)
Citric acid plays a vital role in cellular respiration. It is a key intermediate in the Krebs cycle which occurs in the mitochondria and helps produce energy (ATP) from glucose and oxygen.
2. pH Regulation in the Body
Citric acid helps maintain the acid-base balance in bodily fluids ensuring proper metabolic functions.
Health Benefits and Safety of Citric Acid
1. Health Benefits
- Boosts nutrient absorption – Citric acid enhances the uptake of minerals like iron calcium and magnesium.
- Promotes kidney health – It prevents kidney stone formation by binding to calcium in the urine.
- Aids digestion – Citric acid stimulates enzyme production and improves digestion.
2. Safety and Side Effects
Citric acid is generally safe when consumed in moderate amounts. However excessive intake may cause:
- Tooth enamel erosion due to its acidity.
- Stomach irritation in individuals with acid reflux.
- Allergic reactions in rare cases.
Comparison of Citric Acid with Other Organic Acids
| Property | Citric Acid (C₆H₈O₇) | Acetic Acid (C₂H₄O₂) | Lactic Acid (C₃H₆O₃) | Ascorbic Acid (C₆H₈O₆) |
|---|---|---|---|---|
| Found in | Citrus fruits | Vinegar | Yogurt Muscles | Oranges Berries |
| Function | Preservative pH regulator | Acidic flavor | Muscle metabolism | Antioxidant |
| pH Level | 2.2 – 3.5 | 2.4 – 3.4 | 3.5 – 4.0 | 3.0 – 4.2 |
| Uses | Food medicine cleaning | Cooking cleaning | Food health | Immune booster |
Citric acid is more versatile than other organic acids due to its multifunctional roles in food health and industry.
Fun Facts About Citric Acid
- The name “citric acid” comes from the Latin word “citrus” referring to lemon and lime trees.
- Citric acid was first isolated in 1784 by Swedish chemist Carl Wilhelm Scheele.
- It makes up 8% of the dry weight of lemons.
- Citric acid is an antioxidant which helps prevent cell damage.
The chemical formula of citric acid is C₆H₈O₇ making it a tricarboxylic acid widely used in food medicine and industry. It occurs naturally in citrus fruits and is produced industrially through fermentation. Citric acid plays an essential role in metabolism pH regulation and preservation.
With its numerous applications and health benefits citric acid remains one of the most valuable organic acids in everyday life.
