Ascorbates

What are Ascorbates?

Ascorbates are alkaline salts of ascorbic acid (vitamin C) and a buffered alternative to ascorbic acid. It is a typical additive in foods, beverages and bakery products and can be used as a component of clean label formulations.

The most common ascorbates in food are sodium ascorbate, calcium ascorbate and potassium ascorbate. Sodium ascorbate in foods and baked goods is usually used as a:

• Reducing agent
• Acidity regulator
• Antioxidant
• Source of vitamin C
• Curing agent (in meat)

Origin

Ascorbates are derived from ascorbic acid, which is abundant in the cell walls of plants. Citrus fruits, papaya, pineapple and other fruits and vegetables are rich sources of ascorbic acid.  It can also be synthesized from sugars using chemical and microbial processes.¹

Physicochemical properties of sodium ascorbate:²

• White crystalline powder but can darken when exposed to light
• Melting point: 190-192 °C
• Solubility: highly water soluble but limited solubility in ethanol
• pH of 10% aqueous solutions is 6.5 – 8.0

Typical functionality of sodium ascorbate in baking include:

• Flour improving
• Dough conditioning
• Reduced oxidation

As the salt of ascorbic acid, sodium ascorbate is buffered and less acidic than ascorbic acid. Bread doughs made with sodium ascorbate are generally less stiff and relaxed. This is beneficial for supporting dough rising.

As a reducing agent, sodium ascorbate can weaken the wheat protein network. This translates into reduced mixing time, reduced proofing time and improved machinability.

Commercial Production

Ascorbates are made by combining ascorbic acid with an alkali. For example, sodium ascorbate is made by:

• Dissolving ascorbic acid in water
• Mixing with equivalent amounts of sodium bicarbonate solution
• After effervescence stops, isopropanol is added to form sodium ascorbate precipitate

Nutrition

Sodium ascorbate contains 889 mg ascorbic acid and 111 mg sodium per 1,000 mg of sodium ascorbate. Compared to ascorbic acid, sodium ascorbate is much milder on the gastrointestinal system. This is due to its buffering nature. However, similar to ascorbic acid, it helps with growth, bone regeneration, wound healing, coenzyme, development and repair of body tissues as well as in supporting healthy immune system.³

Application

Baked goods can be fortified with ascorbic acid by directly adding fruits such as lemon, blackcurrant, orange, raspberry, strawberry, or blueberries into the formulation. Fortification with sodium ascorbate can be done by direct addition to the flour or to the baking mix.

Ascorbates are best suited for no-time dough systems. Gluten-free baked goods with potato flour also incorporate a small portion of ascorbate. Especially, when milk is used as the liquid component. The role of ascorbate here is to improve the dough ability to retain gas, thus improving bread oven spring. This also produces bread with a fine and uniform crumb cell structure with good resilience. These characteristics convey to the consumer the impression of freshness.⁴

FDA Regulation

Ascorbic acid is considered as ‘GRAS’  by the FDA.⁵
 

References

1. Linster, Carole L, and Steven G Clarke. L-Ascorbate biosynthesis in higher plants: the role of VTC2. Trends in plant science 13 (2008): 567-73.
2. Ascorbate. https://pubchem.ncbi.nlm.nih.gov/compound/ASCORBATE. Accessed by Dec 17. 2019.
3. Nutrition and healthy eating. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/vitamin-c/faq-20058030. Accessed by Dec 17. 2019.
4. Cauvain, S. and Young, L.  Baking Problems Solved. 2001. Woodhead Publishing, p. 55.
5. Ascorbic acid. https://www.drugs.com/inactive/ascorbic-acid-10.html. Accessed by Dec 17. 2019.