Difference Between Ascorbic Acid and Citric Acid

Main Difference – Ascorbic Acid vs Citric Acid 

Citric acid and ascorbic acid are two weak natural organic acids that occur naturally in fresh leaves, fruits and vegetables, particularly citrus fruits such as oranges, lemons and limes. Both acids have nutritional benefits, and they’re commonly used in food manufacturing and as a preservative, but there are few differences between the two compounds, including a difference in flavor. However, there seems to be a lot of confusion over the difference between ascorbic acid and citric acid. The main difference between Ascorbic acid and citric acid is that ascorbic acid is a water-soluble vitamin and has a chemical make-up of C6H8O6 whereas citric acid has one more oxygen atom than ascorbic acid formula, making its chemical formula C6H8O7. This article, highlight the difference between ascorbic acid and citric acid in terms of their intended uses and other chemical characteristics.

What is Ascorbic Acid

Ascorbic acid is commonly known as vitamin C. It is an essential nutrient for humans, and it is needed for human tissue growth, repair, and wound healing. Furthermore, it’s also an antioxidant, which helps to protect cells from constituents that damage DNA and improve the function of immune system. This vitamin is a water-soluble and heat-sensitive vitamin. As a result, it’s not stored in the human body, and it can be destroyed during food processing when foods are heated or canned. But, ascorbic acid can be incorporated or fortified into foods to increase or substitute vitamin C that is lost during the cooking process. The daily recommended dietary allowance for vitamin C is 75 milligrams for adult women and 90 milligrams for men. However, smokers require an additional 35 milligrams each day.

Main Difference - Ascorbic Acid vs Citric Acid

Sample of Ascorbic Acid

What is Citric Acid

Citric acid is also a weak organic acid, and it has antioxidant properties. Unlike ascorbic acid,  it’s not a vitamin or an essential nutrient. Ascorbic acid acts as an acid buffer and can support to control acidity in the body. Citric acid is also used as a food preservative agent. Natural sources of citric acid are lemon, lime, grapefruit and orange juice, as well as lemonade. Citric acid can enhance the bioavailability of minerals like iron, calcium, and magnesium.

Difference Between Ascorbic Acid and Citric Acid

Citrus fruits such as lemons, oranges, and lime contain high concentrations of citric acid.

Difference Between Ascorbic Acid and Citric Acid


Ascorbic acid: Ascorbic acid is a naturally occurring weak organic acid.

Citric acid: Citric acid is a weak organic tribasic acid.

Represent a vitamin

Ascorbic acid: Ascorbic acid,also known as vitamin C, is an essential vitamin to the human body.

Citric acid: Citric acid is not a vitamin.


Ascorbic acid: Its IUPAC name is (5R)-[(1S)-1,2-Dihydroxyethyl]-3,4-dihydroxyfuran-2(5H)-one.

Citric acid: Its IUPAC name is 3-carboxy-3-hydroxypentane-1,5-dioic acid.

Other Names

Ascorbic acid: It’s also known as Vitamin C.

Citric acid: It’s also known as 3-carboxy-3-hydroxypentanedioic acid, 2-hydroxy-1,2,3-propanetricarboxylic acid

Chemical Formula

Ascorbic acid: Its chemical formula is C6H8O6.

Citric acid: Its chemical formula is C6H8O7.

Molecular Formula

Ascorbic acid:Difference Between Ascorbic Acid and Citric Acid - 1

Citric acid:

Difference Between Ascorbic Acid and Citric Acid -2

Molar Mass

Ascorbic acid: Its molar mass is 176.12 g·mol−1

Citric acid: Its molar mass is 192.12 g·mol−1


Ascorbic acid: It is white or light yellow solid.

Citric acid: It is crystalline white solid.


Ascorbic acid: Its density is 1.65 g/cm3

Citric acid: Its density is 1.665 g/cm3


Ascorbic acid: Its E-numbers include

  • E300 ascorbic acid
  • E301 sodium ascorbate
  • E302 calcium ascorbate
  • E303 potassium ascorbate
  • E304 fatty acid esters of ascorbic acid (i) ascorbyl palmitate (ii) ascorbyl stearate

Citric acid: Its E-number is E330

Natural Food Sources

Ascorbic acid: Green leafy vegetables, yellow and green color fruits and vegetables such as Indian gooseberry, guava, banana, etc. contain ascorbic acid.

Citric acid: Lemon, lime, grapefruit, lemonade, oranges and orange juice contain citric acid.

Uses and Functions

Ascorbic acid:

  • Act as a powerful antioxidant
  • Use as a food preservative agent
  • Enhance the bioavailability of dietary iron

Citric acid:

  • Use as a food preservative agent
  • Use as Cleaning and chelating agentDifference Between Ascorbic Acid and Citric Acid- infogrpahic

In conclusion, ascorbic acid and citric acid are different weak organic acids and they have different chemical and sensory properties.


Lotfy, Walid A.; Ghanem, Khaled M.; El-Helow, Ehab R. (2007). Citric acid production by a novel Aspergillus niger isolate: II. Optimization of process parameters through statistical experimental designs. Bioresource Technology 98 (18): 3470–3477.

Zheng, F. Xiao, L.M. Qian, Z.R. Zhou; Xiao; Qian; Zhou (December 2009). Erosion behavior of human tooth enamel in citric acid solution. Tribology International 42 (11–12): 1558–1564.

Davies, Michael B.; Austin, John; Partridge, David A. (1991). Vitamin C: Its Chemistry and Biochemistry. The Royal Society of Chemistry. p. 48. ISBN 0-85186-333-7.

Image Courtesy:

“Sample of ascorbic acid” By LHcheM – Own work  via

“Lemons, oranges, and lime” (Public Domain) via

“Structure of citric acid” by NEUROtiker – Own work (Public Domain) via

“L-ascorbic acid” by Yikrazuul – Own work (Public Domain) via

About the Author: Geesha

Geesha has a BSc (Hons) degree in Food Science and Technology and Master's degree in Food and Nutrition. She is currently reading for her PhD in Food science and technology. Sharing what she learned is a passion of hers and enjoys writing.

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