Difference Between Ascorbic Acid and Sodium Ascorbate

Main Difference – Ascorbic Acid vs Sodium Ascorbate

Vitamin C is an important vitamin that is useful for our body to defend against many infections and diseases. Vitamin C supplements are available as dietary supplements. There are two types of supplements: ascorbic acid and sodium ascorbate. Generally, vitamin C is the L isomer of ascorbic acid. But this type of supplement can cause hyperacidity in the human body. Sodium ascorbate supplement is introduced in order to avoid this side effect. This is the main difference between ascorbic acid and sodium ascorbate.

Key Areas Covered

1. What is Ascorbic Acid
      – Definition, Chemical Properties
2. What is Sodium Ascorbate
      – Definition, Chemical Properties
3. What is the Difference Between Ascorbic Acid and Sodium Ascorbate
      – Comparison of Key Differences

Key Terms: Ascorbic Acid, Citrus Fruits, Enantiomers, Hyperacidity, Isomer, Monoclinic Crystals, Sodium Ascorbate, Vitamin C

What is Ascorbic Acid

Ascorbic acid is also known as vitamin C. It can be found in food and is an important vitamin which helps to defend the body from infections and diseases by making the immune system strong. It is very important in iron absorption. Ascorbic acid is an antioxidant.

The chemical formula of ascorbic acid is C6H8O6. The molar mass is 176.124 g/mol. This compound can be found in citrus fruits and many other vegetables. It is advised not to cook vegetables containing this compound because it can easily be destroyed while cooking.

Figure 1: Chemical Structure of Ascorbic Acid

Ascorbic acid is a water soluble vitamin. It is available as a crystalline powder. This powder is in white to pale yellow color. It has an acidic taste and is odorless. The melting point of ascorbic acid is about 190oC. The boiling point is 553 °C. The pH of this acid is around pH 3. Ascorbic acid can be found in the form of ascorbate: the ionized form of ascorbic acid at pH conditions such as pH 5.

Figure 2: Citrus Fruits

When considering the stability of ascorbic acid, it is stable in open atmosphere when in the form of dry powder. But aqueous solutions of ascorbic acid are rapidly oxidized by air when exposed. This oxidation can be catalyzed by iron and copper.

Ascorbic acid can exist in two enantiomers as L-ascorbic and D-ascorbic. The term vitamin C always refers to the L isomer. Ascorbic acid can be in the oxidized form or the reduced form. What we call vitamin C is the oxidized L-ascorbic enantiomer.

What is Sodium Ascorbate

Sodium ascorbate is the sodium salt of L-ascorbic acid. Therefore, it is also known as Sodium L-ascorbate. The chemical formula of this compound is C6H7O6Na. The molar mass of sodium ascorbate is 198.106 g/mol. This compound is also found in citrus fruits and vegetables.

Sodium ascorbate appears as minute crystals or a white to pale yellow powder. It is an odorless compound. At 218oC temperature, this compound decomposes. Sodium ascorbate is an approved food additive. It is also a water soluble vitamin compound.

Figure 3: Sodium Ascorbate Powder

Sodium ascorbate is also considered as vitamin C because there is only a slight difference in the chemical structure. Sodium ascorbate is a good substitute for ascorbic acid since it doesn’t have the side effect caused by ascorbic acid – hyperacidity.

Aqueous solutions of sodium ascorbate are unstable and can undergo oxidation by air. Hence, when it is used as a drug, it should be well protected from air and light. The pH of a sodium ascorbate solution is about 5.6-7.0.

Difference Between Ascorbic Acid and Sodium Ascorbate

Definition

Ascorbic Acid: Ascorbic acid is Vitamin C that is composed of L-ascorbic acid.

Sodium Ascorbate: Sodium ascorbate is the sodium salt of L-ascorbic acid.

Chemical Formula

Ascorbic Acid: The chemical formula of ascorbic acid is C6H8O6.

Sodium Ascorbate: The chemical formula of sodium ascorbate is C6H7O6Na.

Molar Mass

Ascorbic Acid: The molar mass of ascorbic acid is 176.124 g/mol.

Sodium Ascorbate: The molar mass of sodium ascorbate 198.106 g/mol.

Melting Point

Ascorbic Acid: The melting point of ascorbic acid is 190°C.

Sodium Ascorbate: Sodium ascorbate decomposes at 218oC.

Appearance

Ascorbic Acid: Ascorbic acid is a crystalline powder including needle shape or monoclinic crystals.

Sodium Ascorbate: Sodium ascorbate appears as minute crystals or a white to pale yellow powder.

Side Effects

Ascorbic Acid: Ascorbic acid can cause hyperacidity.

Sodium Ascorbate: Sodium ascorbate doesn’t cause hyperacidity.

Conclusion

Ascorbic acid and sodium ascorbate are two types of vitamin C supplements. The main difference between ascorbic acid and sodium ascorbate is that ascorbic acid can cause hyperacidity in the human body whereas sodium ascorbate can avoid hyperacidity and act as a vitamin C supplement.

References:

1. “Vitamin C.” Wikipedia, Wikimedia Foundation, 14 Nov. 2017, Available here.
2. “l-Ascorbic acid.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
3. “SODIUM ASCORBATE.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.

Image Courtesy:

1. “Ascorbic acid structure” By en:user:Mykhal / en:user:Cacycle / User:Jrockley – self made, using Image:Dehydroascorbic acid.png (Public Domain) via Commons Wikimedia
2. “Citrus Fruit” (Public Domain) via PublicDomainPictures.net
3. “Sodium ascorbate powder” By Mfomich – Own work (CC0) via Commons Wikimedia

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