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Sodium benzoate also known as benzoate of soda is the sodium salt of benzoic acid, widely used as a food preservative (with an E number of E211) and a pickling agent. It appears as a white crystalline chemical with the formula C6H5COONa.
ProductionEdit
Sodium benzoate is commonly produced by the neutralization of sodium hydroxide (NaOH) with benzoic acid (C6H5COOH),<ref name="sodium benzoate">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> which is itself produced commercially by partial oxidation of toluene with oxygen.
ReactionsEdit
Sodium benzoate can be decarboxylated with strong base and heat, yielding benzene:<ref>Template:Cite book</ref>
Natural occurrenceEdit
Sodium benzoate is not a naturally occurring substance. However many foods are natural sources of benzoic acid, its salts, and its esters.<ref>Template:Cite journal</ref> Fruits and vegetables can be rich sources, particularly berries such as cranberry and bilberry. Other sources include seafood, such as prawns, and dairy products.Template:Citation needed
UsesEdit
As a preservativeEdit
Sodium benzoate can act as a food preservative. It is most widely used in acidic foods such as salad dressings (for example acetic acid in vinegar), carbonated drinks (carbonic acid), jams and fruit juices (citric acid), pickles (acetic acid), condiments, and frozen yogurt toppings. It is also used as a preservative in medicines and cosmetics.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }} National Library of Medicine </ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Under these conditions it is converted into benzoic acid (E210), which is bacteriostatic and fungistatic. Benzoic acid is generally not used directly due to its poor water solubility. Concentration as a food preservative is limited by the FDA in the U.S. to 0.1% by weight.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Sodium benzoate is also allowed as an animal food additive at up to 0.1%, per the Association of American Feed Control Officials.<ref>Template:Cite journal</ref> Sodium benzoate has been replaced by potassium sorbate in the majority of soft drinks in the United Kingdom.<ref name=":0">Template:Cite journal</ref>
In the 19th century, sodium benzoate as a food ingredient was investigated by Harvey W. Wiley with his 'Poison Squad' as part of the US Department of Agriculture. This led to the 1906 Pure Food and Drug Act, a key event in the early history of food regulation in the United States.
In pharmaceuticalsEdit
Sodium benzoate is used as a treatment for urea cycle disorders due to its ability to bind amino acids.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> This leads to excretion of these amino acids and a decrease in ammonia levels. Recent research shows that sodium benzoate may be beneficial as an add-on therapy (1 gram/day) in schizophrenia.<ref name="Add-on Treatment of Benzoate for Schizophrenia A Randomized, Double-blind, Placebo-Controlled Trial of d-Amino Acid Oxidase Inhibitor">Add-on Treatment of Benzoate for Schizophrenia A Randomized, Double-blind, Placebo-Controlled Trial of d-Amino Acid Oxidase Inhibitor December 2013</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Mental Health Research Institute Staff Publications, University of Michigan. Mental Health Research Institute</ref> Total Positive and Negative Syndrome Scale scores dropped by 21% compared to placebo.
Sodium benzoate, along with phenylbutyrate, is used to treat hyperammonemia.<ref name="rush">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite book</ref>
Sodium benzoate, along with caffeine, is used to treat postdural puncture headache, respiratory depression associated with overdosage of narcotics,<ref>Template:Cite journal</ref><ref>mayoclinic.org, Caffeine And Sodium Benzoate (Injection Route)</ref> and with ergotamine to treat vascular headache.<ref>ebi.ac.uk, CHEBI:32140 - sodium caffeine benzoate</ref>
Other usesEdit
Sodium benzoate is also used in fireworks as a fuel in whistle mix, a powder that emits a whistling noise when compressed into a tube and ignited.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
Mechanism of food preservationEdit
The mechanism starts with the absorption of benzoic acid into the cell. If the intracellular pH falls to 5 or lower, the anaerobic fermentation of glucose through phosphofructokinase decreases sharply,<ref>Template:Cite journal</ref> which inhibits the growth and survival of microorganisms that cause food spoilage.
Health and safetyEdit
In the United States, sodium benzoate is designated as generally recognized as safe (GRAS) by the Food and Drug Administration.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The International Programme on Chemical Safety found no adverse effects in rats at doses of 647–825 mg/kg of body weight per day.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=Tox-1>Template:Cite journal</ref>
Cats have a significantly lower tolerance against benzoic acid and its salts than rats and mice.<ref>Template:Cite journal</ref>
The human body rapidly clears sodium benzoate by combining it with glycine to form hippuric acid which is then excreted.<ref name=Tox-1 /> The metabolic pathway for this begins with the conversion of benzoate by butyrate-CoA ligase into an intermediate product, benzoyl-CoA,<ref>{{#invoke:citation/CS1|citation |CitationClass=web }} Substrate/Product</ref> which is then metabolized by glycine N-acyltransferase into hippuric acid.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }} Substrate/Product</ref>
Association with benzene in soft drinks and pepper saucesEdit
{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} In combination with ascorbic acid (vitamin C, E300), sodium benzoate and potassium benzoate may form benzene. In 2006, the Food and Drug Administration tested 100 beverages available in the United States that contained both ascorbic acid and benzoate. Four had benzene levels that were above the 5 ppb Maximum Contaminant Level set by the Environmental Protection Agency for drinking water.<ref name=FDA>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Most of the beverages that tested above the limit have been reformulated and subsequently tested below the safety limit.<ref name=FDA/> Heat, light and shelf life can increase the rate at which benzene is formed. Hot peppers naturally contain vitamin C ("nearly as much as in one orange"<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>) so the observation about beverages applies to pepper sauces containing sodium benzoate, like Texas Pete.
ADHD and hyperactivityEdit
Research published, including in 2007 for the UK's Food Standards Agency (FSA) suggests that certain artificial colors, when paired with sodium benzoate, may be linked to hyperactive behavior and other ADHD symptoms. The results were inconsistent regarding sodium benzoate, so the FSA recommended further study.<ref name="Food Standards Agency issues revised advice on certain artificial colours">Food Standards Agency issues revised advice on certain artificial colours Template:Webarchive 6 September 2007</ref><ref name="myomancy-7-9-7">Food Colorings and Hyperactivity Template:Webarchive "Myomancy" 7 September 2007</ref><ref name="(Food Standards) Agency revises advice on certain artificial colours">Agency revises advice on certain artificial colours Template:Webarchive, Food Standards Agency, 11 September 2007</ref> The Food Standards Agency concluded that the observed increases in hyperactive behavior, if real, were more likely to be linked to the artificial colors than to sodium benzoate.<ref name="(Food Standards) Agency revises advice on certain artificial colours"/> The report's author, Jim Stevenson from Southampton University, said: "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. . . . Many other influences are at work but this at least is one a child can avoid."<ref name="(Food Standards) Agency revises advice on certain artificial colours"/>
Compendial statusEdit
- British Pharmacopoeia<ref name=sb /><ref name=cs>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref><ref name=ibp>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
- European Pharmacopoeia<ref name=sb />
- Food Chemicals Codex<ref name=sb>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- Japanese Pharmacopoeia<ref name=jp15e>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- United States Pharmacopeia<ref name=rusp>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
See alsoEdit
ReferencesEdit
External linksEdit
- International Programme on Chemical Safety - Benzoic Acid and Sodium Benzoate report
- Template:Cite journal
- Safety data for sodium benzoate Template:Webarchive
Template:Sodium compounds Template:Other alimentary tract and metabolism products Template:Diagnostic agents Template:Consumer Food Safety .