Difference Between Tartaric Acid and Citric Acid

The main difference between tartaric acid and citric acid is that the tartaric acid naturally occurs in grapes whereas citric acid naturally occurs in citrus fruits.

Tartaric acid and citric acid are two types of plant acids used as natural food additives. Both these food additives are available in powder and liquid forms. Also, both of them give a sour taste to the food. They have preservative properties as they prevent bacterial growth. Both tartaric acid and citric acid are antioxidants as well. 

Key Areas Covered

1. What is Tartaric Acid
     – Definition, Facts, Importance
2. What is Citric Acid
     – Definition, Facts, Importance
3. What are the Similarities Between Tartaric Acid and Citric Acid
     – Outline of Common Features
4. What is the Difference Between Tartaric Acid and Citric Acid
     – Comparison of Key Differences

Key Terms: Antioxidant, Citric Acid, Plant acids, Preservatives, Tartaric Acid

What is Tartaric Acid

Tartaric acid (also known as dihydroxybunedioic acid or dicarboxylic acid) is a white crystalline organic acid. Grape is the natural source of this acid. Its salt, the potassium hydrogen tartrate, is called the cream of tartar. It is a by-product of wine fermentation.

Figure 1: Commercial Tartaric Acid

Tartaric acid serves as an acidulant in carbonated drinks, gelatin desserts, etc. Cream of tartar is an ingredient in baking powder, taffies, and hard candies.

What is Citric Acid

Citric acid is a weak organic acid, and is an intermediate of Krebs cycle as well. Citrus fruits are the natural sources of this food additive, and it is commercially isolated from citrus fruit juice.

Figure 2: Citric Acid Structure

Citric acid forms chelating complexes having metal ions with large stability constants. Therefore, citric acid also functions as a chelater. 

Similarities Between Tartaric Acid and Citric Acid

• Tartaric acid and citric acid are natural food additives.
• Both acids give a sour taste to the food.
• They both serve as preservatives since they prevent bacterial growth on food.
• Both are antioxidants.
• The two food additives are available in powder and liquid forms.

Difference Between Tartaric Acid and Citric Acid

Definition

Tartaric Acid: A white crystalline organic acid, which naturally occurs in grapes

Citric Acid: A weak organic acid, which naturally occurs in citrus fruits

Molecular Formula

Tartaric Acid: C₄H₆O₆

Citric Acid: C₆H₈O₇

Molecular Weight

Tartaric Acid: 150.086 g/mol

Citric Acid: 192.123 g/mol

Found in

Tartaric Acid: Found in grapes and grape-based wine

Citric Acid: Found in citrus fruit such as limes, lemons, and pineapples

Sourness

Tartaric Acid: Sour

Citric Acid: Less sour 

Importance

Tartaric Acid: An antioxidant

Citric Acid: Adds a sour taste to food and soft drinks

E Number

Tartaric Acid: E334

Citric Acid:  E330

Conclusion

Tartaric acid and citric acid are naturally occurring plant acids. They serve as food additives, which give a sour taste to the food. Tartaric acid occurs in grapes while citric acid occurs in citrus food. The main difference between tartaric acid and citric acid is in their natural sources.

Reference:

1. Brown, William H. “Tartaric Acid.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 17 Apr. 2016, Available here.

Image Courtesy:

1. “CommercialTartaric” By Rei at English Wikipedia – Transferred from en.wikipedia to Commons (CC BY-SA 3.0) via Commons Wikimedia
2. “Citric-acid-3D-balls” By Benjah-bmm27 – Own work (Public Domain) via Commons Wikimedia