Sodium in food

In this chapter, the reader will learn about the production of sodium in stars, the chemistry of sodium, the role of sodium in food, and useful applications of sodium. 

Goldman, Erik L. New DASH Findings Push for Lower Sodium Intake. Family Practice News 30 (2000) 13. International Medical News Group. This article describes why some hypertension experts recommend minimizing sodium in food. 

Chloride is one of the most common inorganic anions in food. Its content is usually related to presence of sodium. In food industry, it is commonly added in the form of NaCl as a preservative or to enhance sapidity of the final products. 

Reddy and Marth (1991) have reviewed the literature on the reduction of sodium in food products. Cheddar cheese made using a KCl/NaCl mixture in place of NaCl alone had a lower count of Staphylococcus aureus (Koenig and Marth, 1982). Low-sodium cheese with added glucono-y-lactone demonstrated resistance to C. botulinum toxin formation (Reddy and Marth, 1991). Salt blends have been used in cottage cheese, butter, buttermilk and ice cream (Reddy and Marth, 1991). 

Bohman and colleagues described a reverse-phase HPLC method for the quantitative analysis of vitamin A in food using the method of standard additions. In a typical example, a 10.067-g sample of cereal is placed in a 250-mL Erlenmeyer flask along with 1 g of sodium ascorbate,... 

Benzoates. The sodium and potassium salts of ben2oic acid [65-85-0], C2H 02, ate most effective against yeast and mold. They ate used in beverages, fmit products, chemically leavened baked goods, and condiments. Owing to their inhibitory effect on yeast, they cannot be used in yeast-leavened products. Potassium ben2oate was developed for use in reduced-sodium products. Ben2oates ate permitted for use in foods up to a level of 0.1% (76). 

Sulfur Dioxide and Sulfites. Sulfur dioxide [7446-09-5], SO2, sodium bisulfite [15181-46-1], NaHSO, and sodium metabisulfite [23134-05-6] ate effective against molds, bacteria, and certain strains of yeast. The wine industry represents the largest user of sulfites, because the compounds do not affect the yeast needed for fermentation. Other appHcations include dehydrated fmits and vegetables, fmit juices, symps and concentrates, and fresh shrimp (79). Sulfites ate destmctive to thiamin, and cannot be used in foods, such as certain baked goods, that ate important sources of this vitamin. 

Lactic acid is generally recognized as safe (GRAS) for multipurpose food use. Lactate salts such as calcium and sodium lactates and esters such as ethyl lactate used in pharmaceutical preparations are also considered safe and nontoxic (7). The U.S. Food and Dmg Administration fists lactic acid (all isomers) as GRAS and sets no limitations on its use in food other than current good manufacturing practice (46). 

The viscosity of solutions is quite temperature dependent increasing the temperature leads to a reduction in viscosity, which approaches zero at approximately 60°C (322). The viscosity is relatively stable from pH 3—10 and is compatible with a number of inorganic salts other than sodium. The production of succinoglycan and its potential use in foods and industrial processes as a thickening agent has been described (322). 

Water-soluble crystal modifiers such as yellow pmssiate of soda (YPS) (sodium ferrocyanide decahydrate) or ferric ammonium citrate may also be added to some types of salt as anticaking agents. Both are approved by the U.S. Food and Dmg Administration for use in food-grade salt. YPS and Pmssian Blue (ferric ferrocyanide), are most commonly added to rock salt used for wintertime highway deicing. Concentrations of YPS and Pmssian Blue in deicing salt vary, typically in the range of 20—100 ppm. 

Sodium Intake. Where salt is readily available, most of the world s population chooses to consume about 6,000—11,000 mg of salt or sodium chloride a day so that average daily sodium intake from all sources is 3,450 mg (8,770 mg NaCl) (13). The U.S. EDA s GRAS review puts the amount of naturally occurring sodium in the American diet at 1000—1500 mg/d, equivalent to the amount of sodium in approximately 2500—3800 mg NaCl. Thus the average daily intake of NaCl from food-grade salt used in food processing (qv) and from salt added in cooking or at the table is from 4960—6230 mg NaCl. The requirement for salt in the diet has not been precisely estabUshed, but the safe and adequate intake for adults is reported as 1875—5625 mg (14). The National Academy of Sciences recommends that Americans consume a minimum of 500 mg/d of sodium (1250 mg/d salt) (6,15). 

Sodium Chloride," in Food Chemicals Codex, 4th ed.. National Research Council Committee on Pood Chemicals Codex, National Academy Press, Washington, D.C., 1996. 

Starch succinates [39316-70-6] are also used as thickening agents in foods. The 1-octenylsuccinate half-ester [52906-93-17, sold as its sodium salt [66829-29-6], has surface active (emulsifying) properties. 

Starch sodium phosphate monoesters [11120-02-8] are prepared by heating mixtures of 10% moisture starch and sodium monohydrogen and dihydrogen phosphates or sodium tripolyphosphate. Starch phosphate monoesters are used primarily in foods, such as pudding starches and with oH-in-water emulsions. 

Phenol was the first commercial antiseptic its introduction into hospitals in the 1870s led to a dramatic decrease in deaths from postoperative infections. Its use for this purpose has long since been abandoned because phenol burns exposed tissue, but many modern antiseptics are phenol derivatives. Toluene has largely replaced benzene as a solvent because it is much less toxic. Oxidation of toluene in the body gives benzoic acid, which is readily eliminated and has none of the toxic properties of the oxidation products of benzene. Indeed, benzoic acid or its sodium salt (Na+, C6H5COO ions) is widely used as a preservative in foods and beverages, including fruit juices and soft drinks. 

Sodium nitrite is produced in the human body by the action of saliva on sodium nitrate, and is important in controlling bacteria in the stomach, to prevent gastroenteritis. The body produces more sodium nitrite than is consumed in food. 

Sodium carboxymethylcellulose is acceptable for use in food, and is employed in a variety of foodstuffs. It is used to prevent formation of ice crystals in ice creams to control the consistency of cheese spreads to stabilise the emulsions needed in salad creams and to thicken toothpaste. 

Wedzicha, B.L., Chemistry of Sulphur Dioxide in Foods, Elsevier, Amsterdam, 1984. Damant, A., Reynolds, S., and Macrae, R., The structural identification of a secondary dye produced from the reaction between sunset yellow and sodium metabisulphite, FoodAddit. Contam., 6, 273, 1989. 

The sodium and calcium salts of EDTA (ethylenediaminetetraacetic acid, Fig. 9.3.1.) are common sequestrants in food products. A three-dimensional representation of EDTA is shown in color Fig. 9.3.2. The EDTA ion is an especially effective sequestrant, forming up to six coordinate covalent bonds with a metal ion. These bonds are so named because a lone pair of electrons on a single atom serves as the source of the shared electrons in the bond between the metal ion and EDTA. The two nitrogen atoms in the amino groups and the oxygen... 

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