ASCORBIC ACID, FCC, USP
ASCORBIC ACID, FCC, USP (L-Ascorbic Acid, Vitamin C), is available as white or slightly yellow, odorless or nearly odorless crystals. ASCORBIC ACID has a pleasant, sharp, acidic taste. It gradually darkens on exposure to light. One gram is soluble in about 3.0 ml of water and in about 30 ml of alcohol. It is insoluble in fats and oils. A 5% aqueous solution has a pH of about 2. ASCORBIC ACID melts at 190ºC with some decomposition.
SPECIFICATIONS – FCC, USP
ASCORBIC ACID is produced to meet the specifications of The Food Chemicals Codex III and The United States Pharmacopeia XXII. Test methods are listed in FCC III and UPS XXII.
Assay: Not less than 99% and not more than 100.5% of C6H8O6.
Specific Rotation: Between +20.5 and +21.5 at 25ºC.
Lead: Not more than 10 parts per million.
Arsenic (as As): Not more than 3 parts per million.
Heavy Metals (as Pb): Not more than 20 parts per million.
Residue on Ignition: Not more than 0.1%.
TYPICAL PARTICLE SIZE
ASCORBIC ACID, FCC, USP, is available with the following United States Standard Sieve sizes:
Min. 100% through No. 20 U.S. Standard Sieve.
Max. 5% on No. 30 U.S. Standard Sieve.
ASCORBIC ACID has been used extensively by the food industry since 1795, when the British physician James Lind successfully treated scorbutic sailors with citrus juices. One of the first modern food applications of ASCORBIC ACID occurred 32 years ago, when it was used to stabilize beer. Today ASCORBIC ACID is used in foods as a vitamin, an acid, a curing agent, an antioxidant, an anti-browning agent, a color stabilizer, a bread improver, and a clarity improver in beer. ASCORBIC ACID, FCC, USP, is “generally recognized as safe” (GRAS) as a chemical preservative (21 CFR 182.3013), a dietary supplement (21 CFR 182.5013), and a nutrient (21 CFR 182.8013).
Numerous foods today are fortified or enriched with ASCORBIC ACID or vitamin C. The recommended daily allowance (RDA) of vitamin C for most people is 60 mg/day. Examples of foods that are fortified or enriched with ASCORBIC ACID include breakfast cereals, enriched flour, beverages (powdered drinks, soft drinks), juices (frozen concentrates and non-frozen) yogurt, and many processed fruits and vegetables.
ASCORBIC ACID is used extensively to prevent enzymatic browning in processed fruits, such as apples, peaches, and apricots. The addition of ASCORBIC ACID protects the color and flavor and enriches the Vitamin C content of the products. A typical starting concentration in peaches is 0.15% ASCORBIC ACID in the syrup. For a product that may be held before blanching, such as potatoes, a weak ASCORBIC ACID solution can be utilized. For a product that is to be frozen in a wet pack, apples for example, the addition of 0.02 – 0.03% ASCORBIC ACID to the sugar syrup is a good color preservative. In addition, ASCORBIC ACID can be added to any fruit, jams, jellies, preserves, purees, or slices to inhibit browning.
Fruits are not the only products improved by ASCORBIC ACID; potatoes, cauliflower, mushrooms, olives, nuts, peanut butter, potato chips and sticks, sweet potatoes, and tomatoes are some other foods that utilize ASCORBIC ACID to control browning.
ASCORBIC ACID performs as an antioxidant in much the same way as it controls browning. As an antioxidant, however, it donates hydrogens to molecular oxygen and in doing so is preferentially oxidized, thereby protecting the flavor and pallatability of an array of canned and frozen foods. This type of antioxidant protection is commonly used in flavor systems. ASCORBIC ACID has also been effective in preventing oxidative rancidity of frozen whole milk. Another use of ASCORBIC ACID as an antioxidant is in fish preservation. Fish pieces are dipped in a bath of 0.25% ASCORBIC ACID and 0.25% citric acid to prevent oxidative rancidity.
In meat curing, ASCORBIC ACID, reacts with nitrous acid to form nitric oxide, water, and dehydroascorbic acid. The nitric oxide then combines with hemoglobin to form nitric oxide myoglobin, the characteristic red pigment of cured meat.
The formation of carcinigenic N-Nitroso compounds by the chemical reaction between nitrous acid and various amines is blocked by ASCORBIC ACID. The National Research Council has recommended that ASCORBIC ACID be added to cured meats with nitrite compounds in order to lower the risk of exposure to carcinogenic nitrosamines while alternatives to nitrites are being developed.
When ASCORBIC ACID is used as a flour improver (75 ppm in the British Chorleywood Continuous Process), the result is the strengthening of the gluten to form a stable dough to better retain the gases liberated by yeast fermentation prior to and during the batching stage. The reaction between dehydroascorbic acid and the sulfhydryl groups is presumed to be the actual mechanism of improvement.
ASCORBIC ACID is used by the brewing industry as an antioxidant during the manufacturing of beer to lessen the undesirable effects of the oxidation of beer by molecular oxygen.
Finally, ASCORBIC ACID favorably affects the taste, flavor, and clarity of wine and, in addition, helps stabilize its oxidation-reduction potential in quantities of 25 – 100 mg of ASCORBIC ACID per liter of wine.