Ascorbic Acid

Ascorbic Acid, CAS 50-81-7, E300, is a raw material used as antioxidant, preservative, vitamin in food, cosmetics, food supplements applications. Supplied by ISF CHEM.

Water-soluble vitamin with the formula C6H8O6. Used in food as an antioxidant and preservative (E300).

Ascorbic acid is a white, odorless, crystalline substance that is completely soluble in water, slightly soluble in ethanol and insoluble in diethyl ether solution. Traditionally, ascorbic acid is obtained by converting sorbitol through a seven-step chemical process. A newer fermentation technology has made significant progress by reducing the production cost of 2-keto-L-gulonic acid, an important intermediate in this process.

Ascorbic acid is generally used as an acidity regulator for pH control, and it gives an acidic taste to food products. Used as an antioxidant in many final products, ascorbic acid prevents turbidity and extends shelf life, helps maintain color in the meat industry, acts as an improving agent in the bakery industry, and prevents color fading in fruit pulps and juices. It can also perform similar functions in butter, frozen egg products, powdered and concentrated milk, frozen potato products and similar products.

Ascorbic acid absorbs oxygen and is converted to dehydroascorbic acid in a reversible reaction. This important function prevents oxidative browning in fruits and vegetables, rancidity in meat and seafood, and the development of undesirable odors in milk.

Ascorbic acid has two salts, sodium ascorbate and potassium ascorbate. It is used as an oxygen scavenger, especially in products with headspace such as canned or bottled products. The sodium and calcium salts of ascorbic acid are water-soluble and therefore cannot protect fats from oxidation. For this purpose, the fatty acid esters ascorbyl palmitate and ascorbyl stearate are used. These esters are white or yellowish-white crystalline powders with a slight citrus-like odor, and they act as oxygen scavengers in foods. (The corresponding food additive numbers are: E300 ascorbic acid, E301 sodium ascorbate, E302 calcium ascorbate, E303 potassium ascorbate, E304 fatty acid esters of ascorbic acid, ascorbyl palmitate and ascorbyl stearate.)

In a fruit and vegetable processing context, an ascorbic acid solution exposed to oxidation breaks down into the oxidation and decomposition products 3-deoxy-L-pentose and furfural. In this way, it reacts with oxygen itself and prevents other components in the process from being oxidized by oxygen.

The degree of this oxidation increases in the presence of oxygen, rising temperatures, exposure to sunlight and ultraviolet light, heavy metals such as copper and iron, and strongly acidic or alkaline conditions. For this reason, ascorbic acid should be stored in a dark, cool place and in non-metallic containers.