Ascorbic erythorbic acid

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... 

These compounds are used as antioxidants in food for humans, animal feeds, plastics, soaps, petroleum products, synthetic rubber, and animal and vegetable oils. The amounts produced annually (metric tons) for use in the United States are BHA (1400) BHT (450) PG (230), and the sum of others including ascorbic acid, sodium and calcium ascorbates, erythorbic acid, and gum guaic (< 230). 

FASEB (1979) Evaluation of the Health Aspects of Ascorbic Acid, Sodium Ascorbate, Calcium Ascorbate, Erythorbic Acid, Sodium Erythorbate, and Ascorbyl Palmitate as Food Ingredients. Federation of American Societies for Experimental Biology, Bethesda, Maryland. 

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). 

As a result of having two chiral centers, four stereoisomers of ascorbic acid are possible (Table 1) (Fig. 2). Besides L-ascorbic acid (Activity = 1), only D-araboascorbic acid (erythorbic acid (9)) shows vitamin C activity (Activity = 0.025-0.05). The L-ascorbic acid stmcture (1) in solution and the soHd state are almost identical. Ascorbic acid crystallizes in the space group P2 with four molecules in the unit cell. The crystal data are summarized in Table 2. 

Chromatographic methods, notably hplc, are available for the simultaneous deterrnination of ascorbic acid as weU as dehydroascorbic acid. Some of these methods result in the separation of ascorbic acid from its isomers, eg, erythorbic acid and oxidation products such as diketogulonic acid. Detection has been by fluorescence, uv absorption, or electrochemical methods (83—85). Polarographic methods have been used because of their accuracy and their ease of operation. Ion exclusion (86) and ion suppression (87) chromatography methods have recently been reported. Other methods for ascorbic acid deterrnination include enzymatic, spectroscopic, paper, thin layer, and gas chromatographic methods. ExceUent reviews of these methods have been pubHshed (73,88,89). 

In apphcations where vitamin C activity is unimportant, often D-erythorbic acid (D-araboascorbic acid) can also be used, providing the same antioxidant and reducing properties as L-ascorbic acid. 

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. 

An isomer (molecule with the same number and type of atoms but in a different formation) of ascorbic acid called erythorbic acid is often used as a less expensive antioxidant than ascorbic acid. It has little or no effect as a vitamin, but it has the same antioxidant properties. 

Oxidation of the lipid structure in foods containing oils and fats produces carbonyl compounds which are responsible for the flavor and odor associated with rancidity (B-81MI11508) the use of a suitable antioxidant can delay this process. Several heterocyclic compounds are among the antioxidants suitable for use in food ascorbic acid (69) and certain of its derivatives and erythorbic acid. The quinoline derivative (70) is mainly used as an antioxidant in animal feed, but it can also be used to preserve the color of paprika, chili powder and ground chili. 

Selective phosphorylation of 5,6-O-isopropylidene D-erythorbic acid (D-erpt/zro-hex-2-enono- 1,4-lactone), the 5-epimer of L-ascorbic acid, was performed with phosphoryl chloride at high pH in the presence of pyridine. D-Erythorbate 2-phosphate (155) is obtained as the crystalline magnesium or cyclohexylammonium salts following removal of the 5,6-acetal.351... 

For photographic use it is best to purchase either ascorbic acid or its isomer (mirror image) erythorbic acid. There are other perfectly legitimate forms of Vitamin C that are not legitimate for photo use, such as calcium ascorbate, especially if it is to be dissolved in propylene glycol or triethanolamine. 

L-ascorbic acid (Figure 9-9) is a lactone (internal ester of a hydroxycarboxylic acid) and is characterized by the enediol group, which makes it a strongly reducing compound. The D form has no biological activity. One of the isomers, D-isoascorbic acid, or erythorbic acid, is produced commercially for use as a food additive. L-ascorbic acid is readily and reversibly oxidized to dehydro-L-ascorbic acid (Figure 9-10), which retains vitamin C activity. This compound can be further oxidized to diketo-L-gulonic acid, in a... 

Oxygen scavengers can remove oxygen in a closed system. The most widely used compounds are vitamin C and related substances, ascorbyl palmitate, and erythorbic acid (the D-isomer of ascorbic acid). 

D-lso-ascorbic acid (erythorbic acid see Figure 13.1) also has vitamin activity. in vivo and in cell culmre, it has only about 5% of the biological activity of ascorbate, but this seems to be from poor intestinal absorption and tissue uptake. In vitro with purified enzymes, it has the same cofactor activity as ascorbate. Although it is not a namrally occurring compound, erythorbic acid is widely used interchangeably with ascorbic acid, in cured meats and as an antioxidant in a variety of foods. 

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)... 

Ascorbic Acid and Ascorbic Acid Esters and Saits Vitamin C or ascorbic acid is widespread in nature but sparingly associated with fats of oils because of its hydrophilic nature (95). Ascorbic acid in the free form, salts of sodium and calcium, and esters of stearic and palmitic are commonly used as antioxidants in foods. Erythorbic acid is the D-isomer of naturally present L-ascorbic acid (Figure 10) and is often used as an antioxidant in dried fruits and a cure... 

Figure 10. Chemical structures of L-ascorbic acid, erythorbic acid, and ascorbyl palmitate.

Erythorbic acid (or D-ascorbic acid) (Figure 5) is a white or slightly yellow crystalline powder that is often used in fruits and cured meats to enhance curing action and to stabilize the color of food products (34). Unlike its isomer L-ascorbic acid, erythorbic acid is not a natural constituent of foods and has minimal Vitamin C activity (11). 

Ascorbyl palmitate erythorbic acid sodium ascorbate. 

Erythorbic acid is a stereoisomer of L-ascorbic acid, and is used as an antioxidant in foods and oral pharmaceutical formulations. It has approximately 5% of the vitamin C activity of L-ascorbic acid. 

Erythorbic acid is widely used in food applications as an antioxidant. It is also used in oral pharmaceutical applications as an antioxidant. Erythorbic acid is generally regarded as nontoxic and nonirritant when used as an excipient. Erythorbic acid is readily metabolized and does not affect the urinary excretion of ascorbic acid. 

Several adaptations of the basic fluorometric method are now available for specific application to plasma (48), and to food extracts (49,50). A spectrophotofluorometric assay procedure also has been devised using DEA-Sephadex column to separate erythorbic (isoascorbic acid) and ascorbic acid (51). This is of particular importance since erythorbic acid, a very common food additive, has been suggested to be an antagonist of ascorbic acid (52,53,54). In general, the spectrofluorometric assay procedures involve measurements of fluorescence on solvent extracts of the acidified samples at 365-348 nm and 435-450 nm, as the wavelengths of maximum excitation and emission, respectively (48,50,51). 

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