Sodium Erythorbate

Another group of compounds called oxygen scavengers retard oxidation by reducing the available molecular oxygen. Products in this group are water soluble and include erythorbic acid [89-65-6] C HgO, and its salt sodium erythorbate [6381-77-7] C HgO Na, ascorbyl pahnitate [137-66-6] 22 38 7 ascorbic acid [50-81-7] C HgO, glucose oxidase [9001-37-0] and sulfites (23). 

Commercial sodium sulfite is acceptable for food plants higher grades are used for pharmaceutical and electronic chip manufacturing, but in these higher grades the catalyst is usually changed to sodium erythorbate (at a level of 0.05 to 0.1%, which also provides lower pressure and temperature passivation). 

Erythorbic acid is supplied as white granular crystals or a powder of sodium erythorbate monohydrate C6H706Na H20, having a fivesided ring and a very reactive ene-diol structure (-COH=COH—) it is a sterioisomer of sodium ascorbate, with a MW of 216.1. It is approved under 21CFR 182.304, GRAS. 

Erythorbic acid is available as a 98+% Food Chemical Codex product (as per Pfizer sodium erythorbate FCC, although as Pfizer is now a pharmaceuticals company, much of the world s erythorbate is now supplied from China and other Asian countries) and in many diluted or blended forms, such as Nalco Sur-Gard . The ONDEO Nalco material is typical of products used within the industry, being based on erythorbic acid buffered with amine. A 1% solution of the product has a pH level of 6.3. 

Erythorbic acid and sodium erythorbate are very safe products, widely used in the food industry as antioxidants and alternatives to vitamin C. In the water treatment industry, they are strong reducing agents that reduce metal oxides and hydroxides to their more soluble ferrous forms and promote the passivation of boiler waterside surfaces (magnetite formation). 

The oxygen reaction with sodium erythorbate is catalyzed by traces of nickel, copper, or iron in solution, so stainless steel or plastic stor-... 

Formulated products tend to use a 10 to 20% neutralized erythorbate, buffered to pH of 5 to 6 with ammonia, morpholine, cyclohexy-lamine, diethanolamine (DEA), or triethanolamine (TEA) to reduce the acidity of erythorbic acid. Similarly, amines are used with sodium erythorbate to improve the reaction rate. 

NOTE Formulations based on sodium erythorbate and stabilized with citric acid against premature reaction (thus, they remain safe products, despite the pH level being around 2.0). Formulations based on ammonium erythorbate lose their safe status but have an improved pH of 6.3 to 6.5. 

Where sodium erythorbate is employed, expect the condensate pH to be at least one pH unit lower than with ammonium erythorbate. Sodium erythorbate can be buffered up to pH 4.0 by the addition ofl% DEHA (85% strength product), and this provides some marginal improvement in condensate pH. Where DEHA is added in excess of 1 Wo, the product becomes unstable. 

Annex III lays down the conditions of use for permitted preservatives and antioxidants, with lists of foods and maximum levels in each case. Part A lists the sorbates, benzoates and p-hydroxybenzoates, E 200-E 219 part B lists sulphur dioxide and the sulphites, E 220-E 228 part C lists other preservatives with their uses, including nisin, dimethyl dicarbonate and substances allowed for surface treatment of certain fruits, E 249 potassium nitrite, E 250 sodium nitrite, E 251 sodium nitrate and E 252 potassium nitrate, E 280-E 283 propionic acid and the propionates part D lists the antioxidants E 320 butylated hydroxyanisole (BHA), E 321 butylated hydroxytoluene (BHT), E 310 propyl gallate, E 311 octyl gallate, E 312 dodecyl gallate, E 315 eiythorbic acid and E 316 sodium erythorbate. 

In canned meats, ascorbate also enhanced NOMb production (Reith and Szakaly, 1967b). Without ascorbate, a Mb nitrite molar ratio of 1 5 was needed for optimum formation of NOMb. With ascorbate, a ratio of 1 Mb 3 nitrite was sufficient for maximum NOMb formation. Sodium erythorbate was equivalent to sodium ascorbate for NOMb formation. Canned meats formulated with potassium nitrate showed no formation of cured meat pigment. 

Sodium Erythorbate occurs as a white, crystalline powder or as granules. In the dry state it is reasonably stable in air, but in solution it deteriorates in the presence of air, trace metals, heat, and light. One gram dissolves in about 7 mL of water. The pH of a 1 20 aqueous solution is between 5.5 and 8.0. 

It has been found that glucose, sucrose, casein, albumin, sodium chloride, flour groats, and starch stabilize ascorbic acid (vitamin C).771 The addition of 5% of starch inhibits the decomposition of ascorbic acid.772 Studies on the stability of ascorbic acid, sodium ascorbate, erythorbic acid, and sodium erythorbate showed that some stabilization is observed after the addition of 8% starch.773 It was reported that the interaction is purely physical in nature.774... 

Metal chelation Oxygen scavenging and reducing agents Singlet oxygen quenching Cirtic, Malic, Succinic and Tartaric acids Ethylenediaminetetraacetic acid, Phosphates Ascorbic acid, Ascorbyl palmitate, Erythorbic acid. Sodium erythorbate. Sulfites Carotenoids (p-Carotene, Lycopene and Lutein)... 

E161 Xanthophylls, Eutein 192 E316 Sodium Erythorbate 265... 

Vegetable oil (none) or antioxidants in vegetable oil were added as ingredients in the raw meat emulsions for bologna manufacture. The antioxidants tested were 500 ppm sodium erythorbate (eiythorbate), 200 ppm sodium nitrite (nitrite), and 0.075% rosemary extract (rosemary). The emulsions were cased, cooked, and irradiated at 3 kGy. Volatile compounds measured die next day, and expressol as square root of peak ar count. The numbers were means of four replicates. Adopted from ref (26). 

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