sodium benzoate

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Sodium benzoate
IUPAC name	Sodium benzoate
Other names	E211, benzoate of soda
Identifiers
CAS number	532-32-1 Y
PubChem	517055
RTECS number	DH6650000
SMILES	O=C([O-])C1=CC=CC=C1.[Na+]
Properties
Molecular formula	NaC6H5CO2
Molar mass	144.11 g/mol
Density	1.497 g/cm3
Melting point	300 °C
Solubility in water	soluble
Solubility	soluble in ethanol
Acidity (pKa)	8.0
Hazards
Flash point	100 °C
Autoignition temperature	500 °C
LD50	4100 mg/mg (oral, rat)
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium benzoate (E211) has the chemical formula NaC₆H₅CO₂. It is the sodium salt of benzoic acid and exists in this form when dissolved in water. It can be produced by reacting sodium hydroxide with benzoic acid.

Uses

Sodium benzoate is a preservative. It is bacteriostatic and fungistatic under acidic conditions. It is used most prevalently in acidic foods such as salad dressings (vinegar), carbonated drinks (carbonic acid), jams and fruit juices (citric acid), pickles (vinegar), and condiments. It is also found in alcohol-based mouthwash and silver polish.^{[citation needed]} It can also be found in cough syrups like Robitussin.^[1] Sodium benzoate is declared on a product label as 'sodium benzoate' or E211.

It is also used in fireworks as a fuel in whistle mix, a powder which emits a whistling noise when compressed into a tube and ignited.^{[citation needed]}

Sodium benzoate is produced by the neutralization of benzoic acid with sodium hydroxide.^[2] Benzoic acid is a natural preservative found in cranberries, prunes, greengage plums, cinnamon, ripe cloves, and apples.^{[citation needed]} Though benzoic acid is a more effective preservative, sodium benzoate is more commonly used as a food additive because benzoic acid does not dissolve well in water.^[2] Concentration as a preservative is limited by the FDA in the U.S. to 0.1% by weight. The International Programme on Chemical Safety found no adverse effects in humans at doses of 647–825 mg/kg of body weight per day.^[3][4]

Cats have a significantly lower tolerance against benzoic acid and its salts than rats and mice.^[5] Sodium benzoate is, however, allowed as an animal food additive at up to 0.1%, according to AFCO's official publication.^[6]

Mechanism of food preservation

The mechanism starts with the absorption of benzoic acid into the cell. If the intracellular pH changes to 5 or lower, the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95%.^[7]

Safety and health

In combination with ascorbic acid (vitamin C, E300), sodium benzoate and potassium benzoate may form benzene,^[8] a known carcinogen. Heat, light and shelf life can affect the rate at which benzene is formed.

Professor Piper of the University of Sheffield claims that sodium benzoate by itself can damage and inactivate vital parts of DNA in a cell's mitochondria. Mitochondria consume oxygen to generate ATP, the body's energy currency. If they are damaged due to disease, the cell malfunctions and may enter apoptosis. There are many illnesses now tied to DNA damage, including Parkinson's and other neurodegenerative diseases, but above all, the aging process in general.^{[9][10][11][12][13]}

Hyperactivity

Research published in 2007 for the UK's Food Standards Agency (FSA) suggests that certain artificial colours, when paired with sodium benzoate (E211) may be linked to hyperactive behaviour. The results were inconsistent regarding sodium benzoate, so the FSA recommended further study.^[14][15][16]

Professor Jim Stevenson from Southampton University, and author of the report, said: "This has been a major study investigating an important area of research. The results suggest that consumption of certain mixtures of artificial food colours and sodium benzoate preservative are associated with increases in hyperactive behaviour in children. However, parents should not think that simply taking these additives out of food will prevent hyperactive disorders. We know that many other influences are at work but this at least is one a child can avoid."^[16]

Two mixtures of additives were tested in the research:^[16]

Mix A:

• Sunset yellow (E110)
• Tartrazine (E102)
• Carmoisine (E122)
• Ponceau 4R (E124)
• Sodium benzoate (E211)

Mix B:

• Sunset yellow (E110)
• Quinoline yellow (E104)
• Carmoisine (E122)
• Allura red (E129)
• Sodium benzoate (E211)

Sodium benzoate was included in both mixes, but the effects observed were not consistent. The Food Standards Agency therefore considers that, if real, the observed increases in hyperactive behaviour were more likely to be linked to one or more of the specific colours tested.

On 10 April 2008, the Foods Standard Agency called for a voluntary removal of the colours (but not sodium benzoate) by 2009.^[17] In addition, it recommended that there should be action to phase them out in food and drink in the European Union (EU) over a specified period.^[18]

In response to consumer insistence on a more natural product and E211's links to DNA damage and ADHD, the Coca Cola Company is in the process of phasing Sodium Benzoate out of Diet Coke. The company has stated that it plans to remove E211 from its other products — including Sprite, Fanta, and Oasis — as soon as a satisfactory alternative is discovered.^[19]

Compendial status

• British Pharmacopoeia^[20][21]
• Food Chemical Codex^{[20][clarification needed]}
• European Pharmacopoeia^{[20][clarification needed]}
• Japanese Pharmacopoeia^{[citation needed]}
• United States Pharmacopeia 29^[22]

See also

• Food-induced purpura

Notes & References

External links

• International Programme on Chemical Safety - Benzoic Acid and Sodium Benzoate report
• Kubota K, Ishizaki T (1991). "Dose-dependent pharmacokinetics of benzoic acid following oral administration of sodium benzoate to humans". Eur. J. Clin. Pharmacol. 41 (4): 363–8. PMID 1804654. "Although the maximum rate of biotransformation of benzoic acid to hippuric acid varied between 17.2 and 28.8 mg.kg-1.h-1 among the six individuals, the mean value (23.0 mg.kg-1.h-1) was fairly close to that provided by daily maximum dose (0.5 g.kg-1.day-1) recommended in the treatment of hyperammonaemia in patients with inborn errors of ureagenesis". 
• Andersen A (2006). "Final report on the safety assessment of benzaldehyde". Int. J. Toxicol. 25 (Suppl 1): 11–27. doi:10.1080/10915810600716612. PMID 16835129. http://www.informaworld.com/openurl?genre=article&doi=10.1080/10915810600716612&magic=pubmed||1B69BA326FFE69C3F0A8F227DF8201D0. 
• Sodium Benzoate A Cause of Hyper Kids (TIME.com)
• Safety data for sodium benzoate
• The Ketchup Conundrum