Ascorbic Acid vs Citric Acid: the Differences and Uses

What are Ascorbic Acid and Citric Acid?

Citric acid is naturally found in various fruits and vegetables. Foods high in citric acid include berries like raspberries and strawberries, as well as citrus fruits like lemons and limes. Citric acid is most concentrated in lemons and limes, with their juices containing 1.44 grams and 1.38 grams of citric acid per ounce, respectively. It's known for its antioxidant activity. As per a review published in the Journal of Human Nutrition and Dietetics in 2014, it can even aid in removing aluminum from the body. Citric acid is also manufactured and used in many commercial products, serving as a common food additive. It's used to impart the signature fruity flavor and acidity to soft drinks, as well as enhance the flavor and color of other products. Citric acid is also frequently used as a preservative and can enhance the activity of other antioxidants.

Ascorbic acid is just another name for vitamin C, which our bodies cannot produce on their own. According to the National Institutes of Health, it is recommended that most adults consume 75 to 120 milligrams of vitamin C daily through food or supplements. Vitamin C is associated with preventing various diseases, including age-related macular degeneration, cancer, cataracts, and the common cold. Ascorbic acid is commonly used in the food industry as an effective antioxidant, serving as a preservative that can help slow down food spoilage due to exposure to bacteria, fungi, yeast, mold, and air. The FDA states that antioxidants also prevent fats and oils in food from becoming rancid and off-flavored, as well as prevent fresh fruits from turning brown.

There are some similarities between the two, but also many fundamental differences.

Citric acid and ascorbic acid structure

Is ascorbic acid the same as citric acid? Despite their similar names and presence in citrus fruits, citric acid and ascorbic acid have different chemical structures.

(1) Citric Acid:

Citric acid is an organic acid found in citrus fruits, with a molecular formula of C6H8O7.

(2) Ascorbic Acid (Vitamin C):

Ascorbic acid is an organic acid with antioxidant properties, having a molecular formula of C6H8O6.

The key difference in their structures lies in the arrangement of carbon atoms and the presence of a double bond between two carbon atoms in ascorbic acid, which is absent in citric acid. This subtle difference leads to their different functions.

Comparison of pH Values and Taste between Ascorbic Acid and Citric Acid:

Here's a breakdown of ascorbic acid (vitamin C) and citric acid in terms of pH values and taste:

Ascorbic acid vs citric acid ph:

(1) Citric Acid: Str onger acidity. It has a lower pH compared to ascorbic acid, around 3.5.
(2) Ascorbic Ac id: Lower acidity. Its pH is around 4.0.

Ascorbic Acid vs. Citric Acid Taste:

Both are acidic: They activate taste receptors for sourness on the tongue.

(1) Citric A cid: Known for its sha rp taste due to its lower pH. The acidity activates taste receptors on the tongue, sending signals to the brain to release serotonin. Citric acid is commonly used as an additional coating for hard candies to provide an immediate sour flavor burst.
(2) Ascor bic Acid: Has a milder acidity compared to citric acid and pairs well with citrus flavors. It enhances flavors and adds a hint of acidity.

Is Citric Acid Better Than Ascorbic Acid?

It depends on what you're using it for! Citric acid and ascorbic acid have different uses:

(1) Acidi ty: Citric acid is stronger than ascorbic acid. This makes it more suitable for lowering the pH in canning recipes or adding strong acidity to foods and beverages.
(2) Vita min C: Ascorbic acid is pure vitamin C. It doesn't add as much acidity, but it can prevent browning of fruits and vegetables and provide an increase in vitamin C.

Ascorbic acid vs citric acid in skin care

Ascorbic acid and citric acid are both found in citrus fruits but have different uses in skincare. Here's how they act on the skin:

(1) Ascorbic Acid (Vitamin C): This is a potent antioxidant that can help protect the skin from sun damage, brighten the complexion, and stimulate collagen production . However, it's also unstable and easily degrades when exposed to light and air. Skincare products often use stable forms of vitamin C, such as ascorbyl palmitate or tetrahexyldecyl ascorbate.
(2) Citric Acid: This is an alpha hydroxy acid (AHA) with a wide range of uses: it can regulate the pH of skincare products for maximum efficacy, exfoliate gently to remove dea d skin cells for softer, smoother skin, increase skin thickness—particularly useful for sun-damaged skin—products containing citric acid should lead to smaller pores and reduced acne, a gentler AHA compared to glycolic or lactic acid, citric acid esters with other ingredients to form a protective layer on the skin, limiting the amount of moisture evaporating from the skin and thus promoting hydration. Generally, citric acid is well tolerated, but it can be irritating to some, especially those with sensitive skin.

Overall, if you're looking for anti-aging and brightening effects, ascorbic acid (vitamin C) is a good choice. If you want to improve skin texture and achieve a smoother complexion, citric acid (AHA) might be a better option.

Citric acid vs ascorbic acid in canning

In canning, both citric acid and ascorbic acid have their uses, but they excel in different areas:

Citric Acid:

(1) Fu nction: Primarily used for increasing acidity (lowering pH). This is important for the safety of low-acid foods like tomatoes in canning.
(2) Benefits: More effective acidification compared to ascorbic acid (you need less of it). Generally cheaper.
(3) Drawbacks: Less effective in preventing browning of fruits and vegetables. May have a strong sour taste, which might be undesirable in some recipes.

Ascorbic Acid:

(1) Function: Mainly used for preventing browning (oxidation) of fruits and vegetables.
(2) Benefits: Significantly more effective in preventing browning compared to citric acid. Unlikely to affect the final product's taste.
(3) Drawbacks: Less acidic than citric acid, so not suitable for increasing acidity in low-acid foods to ensure safety. Might be more expensive than citric acid.

Can I use citric acid instead of ascorbic acid

Can I use ascorbic acid instead of citric acid for canning? It's generally not recommended to directly substitute ascorbic acid for citric acid in canned food formulas. Here's why:

(1) Acidity: Citric acid is a stronger acid than ascorbic acid. In low-acid foods, citric acid helps lower the pH to the safe range for canning, preventing the growth of harmful bacteria like Clostridium botulinum. Ascorbic acid is not as effective at reaching this critical acidity level.
(2) Safety: Canning safety is paramount. Using the wrong acid or improper amounts can lead to foodborne illnesses. For low-acid foods, it's best to follow tested recipes that call for citric acid.

Can I Mix Citric Acid and Ascorbic Acid?

Yes, it's safe to mix citric acid and ascorbic acid. In fact, they are sometimes combined in various products due to their complementary properties:

(1) Food and Beverages: Some commercially produced juices or canned fruits may use a mixture of citric acid (for acidity and sourness) and ascorbic acid (to prevent browning).
(2) Skincare Products: Certain skincare products may blend these ingredients. For example, citric acid can be used for exfoliation while ascorbic acid (vitamin C) provides antioxidant benefits.

Here's why mixing them is generally safe:

(1) Chemical Compatibility: Both are organic acids and do not undergo adverse reactions when mixed.
(2) Natural Synergy: They even naturally occur together in fruits such as citrus fruits (lemons, oranges).

Citric acid vs ascorbic acid for pool stains

Citric acid and ascorbic acid are both acids commonly used in pool stain removal processes. Citric acid and ascorbic acid pool stain removers are products used to remove specific types of stains from pool surfaces. Both acids act as reducing agents, removing stains caused by metal particles on the surface and converting them into colorless soluble ions. Citric acid pool stain removers work well, but ascorbic acid is most effective against iron stains and rust stains.

If you have iron stains in your pool, opt for a vitamin C pool stain remover composed of ascorbic acid.

If your pool has copper stains, use a citric acid stain remover. Citric acid is common in many stain removal products and can also be purchased in bulk separately. We recommend using products that contain these acids rather than direct acid-based stain removers, as these products are usually balanced for pool use and may have additional functionalities such as chelating agents and clarifying compounds.

Conclusion

Through this article's comparison and analysis of ascorbic acid and citric acid, we have gained a deeper understanding of the characteristics, uses, and differences between these two organic acids. Ascorbic acid and citric acid have important applications in food, cosmetics, and other fields, but they differ in chemical structure, properties, and functions. Choosing the right organic acid for specific needs is crucial in different applications, and we need to select the appropriate acid based on specific requirements and characteristics. We hope the content of this article helps readers better understand the differences and uses of ascorbic acid and citric acid, enabling them to choose the organic acid that suits their needs. We encourage understanding the differences between ascorbic acid and citric acid and finding solutions that suit your needs.

References:

[1] https://eze-cosmetics.com/blogs/from-our-blog/ascorbic-acid-vitamin-c-and-citric-acid

[2] https://blog.lorannoils.com/2019/04/08/serious-pucker-power

[3] https://pubchem.ncbi.nlm.nih.gov

[4] https://www.livestrong.com/article/164362-difference-between-citric-acid-and-ascorbic-acid/

[5] https://www.ifsqn.com/forum/index.php/topic/43699-can-you-mix-citric-acid-and-ascorbic-acid-in-the-same-product/

[6] https://www.troublefreepool.com/threads/citric-acid-vs-ascorbic-acid-for-metal-stain-removal.7555/

[7] https://pooladvisor.com.au/blog/ascorbic-acid-stain-remover

[8] https://enewsletters.k-state.edu/youaskedit/2019/08/06/citric-acid-vs-ascorbic-acid/