The Ultimate Guide to Erythorbic Acid as A Food Additive

Erythorbic acid, also known as erythritol, isovitamin C, and D-isoascorbic acid, is commonly used as an antioxidant in food additives. This article will explain why erythorbic acid is chosen in the food industry from the perspectives of what isoascorbic acid is, its differences from ascorbic acid and sodium isoascorbate , its core antioxidant mechanism, main application scenarios, application advantages, and comparisons with other antioxidants.

1. What Is The Erythorbic Acid ?

Erythorbic acid is a water-soluble, weak organic acid prepared through fermentation. Its international code is E315 (E number)/INS 315 (International Numbering System), its Chinese food additive CNS number is 04.004 , and its CAS number is 89-65-6. Its chemical formula is C₆H₈O₆. It typically appears as white or slightly yellow crystalline granules or powder, is odorless with a sour taste, and is readily soluble in water. It is highly stable in a dry state but easily decomposes in aqueous solution upon contact with air. It is mainly used as an antioxidant to maintain the color, quality, and flavor of food.

2. What Is The Difference Between Erythorbic Acid And Ascorbic Acid ?

Ascorbic acid is a natural form of vitamin C with a levorotatory structure. Erythorbic acid , produced through the microbial fermentation of glucose, is a compliant synthetic food additive with a dextrorotatory structure. Both possess antioxidant properties, are readily soluble in water, and have similar appearances, leading to frequent confusion. However, their spatial structures differ, resulting in variations in their biological activities and applications . They cannot be used interchangeably.

The above describes the differences in molecular formulas. The table below clearly shows the specific differences between D-isoascorbic acid and ascorbic acid.

3. What Is The Difference Between Isoascorbic Acid And Sodium Isoascorbate ?

Isoascorbic acid and sodium isoascorbate differ by only one character in their names, but their applications are vastly different. The main differences lie in their chemical forms and pH levels. D-Isoascorbic acid is a free acid ; its aqueous solution is acidic and relatively unstable. It is generally used in slightly acidic food systems to fine-tune the pH value of food. Sodium isoascorbate is the sodium salt of isoascorbic acid; it has no acidic taste, is neutral or slightly alkaline, and its aqueous solution is more stable and less prone to decomposition. It is generally used as an additive in neutral or alkaline foods, commonly found in meat and seafood products.

The table below clearly shows the specific differences between isoascorbic acid and sodium isoascorbate.

Having discussed the differences between D-isoascorbic acid, common vitamin C, and its sodium salt, the next focus will be on why isoascorbic acid is an effective antioxidant. If you need to learn more about other antioxidants, such as vitamin E, please refer to this page.

4. Isoflavone Core Antioxidant Mechanism

Food will spoil if not consumed promptly in an oxygen-rich environment. Therefore, it's crucial to minimize oxygen molecules in food during processing and storage to prevent oxidation. Food oxidation leads to rancidity of oils, fading and discoloration of natural pigments, and a decline in taste and flavor.

The three core antioxidant functions of isoascorbic acid are: strong reducing agent, reduction of myoglobin, and inhibition of polyphenol oxidase.

4.1 Strong Reducing Agent - Binds to Free Oxygen

Isoascorbic acid is a strong reducing agent. When oxygen molecules are present in food, isoascorbic acid preferentially captures and reacts with them, scavenging free radicals. Reducing the number of oxygen molecules in food effectively blocks the reaction between oxygen molecules and other substances, slowing down the oxidation of fats and oils, thus effectively extending the shelf life of food, reducing the possibility of flavor deterioration, and minimizing the loss of beneficial nutrients.

4.2 Reduced Myoglobin - Blocking Nitrosamine Formation

D-Isoascorbic acid plays a crucial role in meat processing, reducing methemoglobin to ferrous myoglobin. Firstly, it promotes the formation of nitrosomyoglobin, a stable bright red pigment that enhances the appearance and appeal of meat products. Secondly, D-isoascorbic acid can bind to the color-protecting agent nitrite, inhibiting the formation of the potent carcinogen nitrosamine, thus making meat products safer to consume.

4.3 Inhibition of Polyphenol Oxidase - Color Protection And Antioxidant

Fruits and vegetables are prone to oxidation and blackening after being cut for a period of time, which greatly affects the eating experience. Adding isoascorbic acid shortly after cutting fruits and vegetables can effectively inactivate polyphenol oxidase activity and inhibit enzymatic browning. It also has a weak metal chelating effect, capable of complexing heavy metal ions such as copper and iron, eliminating the risk of metal ion-catalyzed oxidation, and further enhancing the antioxidant effect.

4.4 Synergistic Effect of Compound Formulation

In food processing, more than one food additive is usually used. To achieve a strong antioxidant effect, a synergistic combination is typically used: isoascorbic acid + citric acid + EDTA-2Na. Citric acid regulates the slightly acidic environment, while EDTA-2Na chelates metal ions, maximizing the effectiveness of D-isoascorbic acid. The combined effect of these three additives can enhance antioxidant and color-protecting properties by 30%+. This approach is suitable for most food processing industries.

5. Main Application Scenarios of Isoascorbic Acid

5.1 Meat Products

Meat products typically include ham, sausages, bacon, cured meats, and cooked meat products. It is recommended to add 0.3-1.0 g/kg of isoascorbic acid to these meat products to maintain their color, flavor, and freshness, prevent discoloration, reduce nitrosamine formation, and extend shelf life.

5.2 Aquatic Products

Aquatic products generally include: frozen fish, shrimp, shellfish, and surimi products. The recommended addition level of isovitamin C is 0.2-0.8 g/kg, which can effectively inhibit protein oxidation, prevent browning and yellowing of meat, and delay the formation of rancid flavor in fats, thus improving the quality of frozen foods.

5.3 Fruit And Vegetable Products

Fruit and vegetable products: canned goods, jams, preserves, freeze-dried fruits and vegetables, juices, etc. The recommended addition level of D-isoascorbic acid is 0.1-0.5g/kg. It effectively combats oxidation, enhances product color, and improves the appearance and quality of the products for sale.

5.4 Beverage Industry

Beverages: Tea drinks, coffee drinks, energy drinks, plant-based drinks, beer, wine, etc. The recommended addition amount of isovitamin C is 0.05-0.3g/kg, which can effectively prevent oxidation, cloudiness, flavor degradation, and color darkening in beverages.

5.5 Baking Pastries

Baked goods: noodles, bread, toast, pizza, cookies, etc. The recommended addition level of isoascorbic acid is 0.2-1g/kg. Combined with calcium propionate, it can effectively delay oil oxidation, reduce mold growth, maintain flavor, and extend shelf life.

6. Advantages of Isoascorbic Acid in The Food Industry

6.1 Highly Effective Antioxidant

Compared to traditional antioxidants, isoascorbic acid requires less dosage, is more stable, and has a more pronounced effect.

6.2 High Food Safety

China is closely following the standards of the Codex Alimentarius Commission (CAC) and other countries, adjusting its use of antioxidants and preservatives that pose potential safety risks. This includes eliminating the use of dehydroacetic acid and its sodium salt in many food categories, and eliminating natamycin from fruit and vegetable juices (pulps). The use of dehydroacetic acid and its sodium salt in pickled vegetables has been reduced, and the scope and limits for sulfur dioxide use have been adjusted. These measures are conducive to promoting the internationalization of China's food safety standards, safeguarding public health, and ensuring the smooth conduct of international trade.

The restricted use of products such as dehydroacetic acid and its sodium salt, natamycin, and sulfur dioxide has reduced the use of chemical preservatives to some extent, which helps D-isoascorbic acid gradually expand its market share and makes it more likely to become one of the important choices for food antibacterial agents.

6.3 Wide Range of Applications

Isoascorbic acid can be found in a wide variety of everyday foods and is one of the most widely used food antioxidants and antibacterial agents. These include cured meats, salted fish, ham, smoked meat, sausages, cured beef, luncheon meat, minced meat, cooked pork shoulder, cooked ham, frozen fish and shrimp, canned mushrooms , canned fruit , jams, dried fruit , plant-based protein drinks , pickles, preserved vegetables , dairy beverages , compound seasonings , sauces (chili sauce, soybean paste, etc.) , eight-treasure porridge , bread , instant noodles , and more. Polifar, as a supplier of isoascorbic acid, has long provided high-quality isoascorbic acid powder. They also provide antioxidants such as vitamin E and vitamin C.

6.4 Low Cost

Isoascorbic acid has a stable price and is cheaper than vitamin C. For food companies, large-scale procurement, stable supply, and stable prices are crucial for production. Isoascorbic acid also has a cost advantage compared to other antioxidants.

7. Comparison of Isoascorbic Acid with Common Antioxidants

There are many antioxidants on the market, and each type has its optimal application scenario. Customers can choose the best antioxidant supplier based on their specific needs.

8. Common Misconceptions about Isovitamin C

Isoascorbic acid and vitamin C are the same product, both supplementing vitamin C. The differences between the two were already pointed out in point two of this article. Isoascorbic acid has almost no physiological activity similar to vitamin C and cannot be used for nutritional fortification . It only has antioxidant and color-protecting properties , without any nutritional function. Ingesting isoascorbic acid does not hinder the body's absorption of natural vitamin C.

For better color-protecting effects, add more isocyanate. However, anything in excess is harmful; moderation is key. Excessive amounts may lead to excessive sourness, abnormal color, and deteriorated taste , ultimately affecting product quality.

D-Isoascorbic acid is a preservative that inhibits bacteria and keeps food fresh. D-isoascorbic acid is only used as an antioxidant and has no bactericidal or preservative effect; it cannot replace common preservatives such as potassium sorbate and sodium benzoate .

FAQ

Q1: Is Food Containing Isoascorbic Acid Safe ?

A1: Isoascorbic acid is one of the safest antioxidants. It has undergone rigorous safety assessments by the National Health Commission of China, JECFA , FDA , and EFSA . Under normal recommended daily intake levels , it does not cause cumulative toxicity or adverse reactions in the human body .

Q2: Will Isoascorbic Acid Accumulate in The Body?

A2: No. D-isoascorbic acid metabolizes similarly to vitamin C after entering the body. The unabsorbed portion is directly excreted in urine and will not accumulate in the body to produce toxins.

Q3: Is Isoascorbic Acid Vegan?

A3: The chemical itself is vegan. It is produced through microbial fermentation using corn starch/glucose as raw materials and contains no animal-derived materials. However, whether the finished product can be labeled as vegan requires verification of the factory's filter aids and cross-contamination on the production line. Purchasers should request a vegan compliance declaration. The same applies to sodium isoascorbate.

Q4: What Are The Side Effects of Isoascorbic Acid ?

A4: When used correctly and in compliance with regulations, it has virtually no side effects. It is a practically non-toxic additive; however, a small number of people may experience gastrointestinal discomfort (acid reflux, diarrhea) when ingested in large doses. For the sodium isoascorbate version, sodium intake should be monitored, and large intake is not recommended. There is no evidence of carcinogenicity or teratogenicity; it is safe for human use when used in accordance with national standards.

Q5: How Is Isoascorbic Acid Manufactured ?

A5: Using glucose obtained from starch hydrolysis as a substrate, an intermediate is obtained through microbial fermentation, followed by chemical transformation, crystallization, purification, and drying to obtain food-grade D-isoascorbic acid powder. It is not directly extracted from plants.

In Conclusion

In the future, isoascorbic acid will continue to have a huge market potential. Currently, it is widely used in the food industry for its antioxidant properties. There is now a trend towards expansion into deoxidizers, cement water-reducing agents, the petroleum and mining industries, and cosmetics. Polifar is a high-quality isoascorbic acid supplier. We provide high-quality isoascorbic acid with stable prices and a reliable supply chain, supporting our customers' stable production. Polifar offers one-stop sourcing services, provides multiple certifications, supports sample services, and can customize products in large quantities or different specifications as needed. Everything we do is to support your business!