E211 - Sodium benzoate

Additive: E211 - Sodium benzoate

Functions: Preservative

Benzoic acid, sodium salt

CAS no.: 532-32-1

EC / List no.: 208-534-8

Mol. Formula: C7H5NaO2

C7H5NaO2 or C6H5COONa

Molar Mass

144.105 g·mol−1

Boiling Point

248.00 to 249.00 °C

Melting Point

410 °C (770 °F; 683 K)

E211 Sodium Benzoate

 

Sodium Benzoate is a preservative commonly used to control bacteria, mold, yeast, and other microbes. 

It is most widely used in acidic foods, including carbonated drinks, salad dressings, condiments, and pickles.

Sodium benzoate, the sodium salt of benzoic acid, is a widely used food preservative with the European food additive number E211

How does Sodium Benzoate work?

Sodium benzoate is a broad-spectrum antimicrobial preservative that is most active against yeast and bacteria, but less effective against mold. 

Suitable PH

Primarily used in acidic food and drink with the PH value at or lower than 4.0-4.5. 

The effectiveness increases with decreasing pH. 

Mechanism of Preservation

When sodium benzoate dissolves in water, it dissociates into benzoate ion and sodium ion.

Then the benzoate ion accepts a proton, forming benzoic acid. 

It is the undissociated benzoic acid that has the inhibiting activity.

The undissociated benzoic acid can easily enter microbial cells through the cell membrane, interfere with the permeability of microbial cell membranes, and disrupt their normal metabolism.  

Properties

A white or colorless crystalline powder or granular, with an astringent sweet taste, odorless or with a faint odor. 

Other Names

Benzoate of Soda

Sodium salt of benzenecarboxylic acid

Sodium salt of phenylcarboxylic acid

Sodium benzoate is a substance that has the chemical formula NaC7H5O2. 

It is a widely used food preservative with the E number E211. 

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. 

What Is Sodium Benzoate?

Sodium benzoate, E211, is best known as a preservative used in processed foods and beverages to extend shelf life, though it has several other uses.

It’s an odorless, crystalline powder made by combining benzoic acid and sodium hydroxide. Benzoic acid is a good preservative on its own, and combining it with sodium hydroxide helps it dissolve in products.

Foods and Beverages

Sodium benzoate is the first preservative the FDA approved for use in foods and remains a widely used food additive. 

It’s classified as Generally Recognized As Safe (GRAS), meaning that experts consider it safe when used as intended.

It’s approved internationally as a food additive and is assigned the identifying number 211. 

For example, it’s listed as E211 in European food products.

Sodium benzoate inhibits the growth of potentially harmful bacteria, mold, and other microbes in food, thus deterring spoilage. 

It’s particularly effective in acidic foods.

Therefore, it’s commonly used in foods, such as soda, bottled lemon juice, pickles, jelly, salad dressing, soy sauce, and other condiments.

Medications

Sodium benzoate is used as a preservative in some over-the-counter and prescription medications, particularly in liquid formulations such as cough syrup.

Additionally, it can serve as a lubricant in pill manufacturing, making tablets transparent and smooth and helping them break down rapidly after you swallow them.

Lastly, larger doses of sodium benzoate may be prescribed to treat elevated blood ammonia levels. 

Ammonia is a byproduct of protein breakdown, and blood levels may become dangerously high in certain medical conditions.

Other Uses

Sodium benzoate is commonly used as a preservative in cosmetics and personal care items, such as hair products, baby wipes, toothpaste, and mouthwash.

It also has industrial uses. One of its biggest applications is to deter corrosion, such as in car engine coolants.

What’s more, it may be used as a stabilizer in photo processing and to improve the strength of some types of plastic.

Solubility

In water: very soluble in water, with solubility 53.0 g/100 mL at 25 °C. 

In organic solvents: sparingly soluble in ethanol (solubility 2.3 g/100 g at 25 °C), methanol, and ethylene glycol; not soluble in ether as it is a very polar molecule due to the negative charge, while ether is a non-polar solvent.

PH

The pKa of benzoic acid is 4.2. 

To achieve a good inhibitory effect, the pH needs to be lower than the pKa. 

That’s to say, a low PH level can convert sodium benzoate to benzoic acid.

What are the Uses of Sodium Benzoate?

Sodium benzoate has been used in a wide variety of food products for its antimicrobial and flavor properties. 

Apart from its use in foods and beverages, it is also added to cosmetics and pharmaceutical products.

Food

In the food industry, sodium benzoate food grade is mainly used to: 

prevent spoilage from harmful bacteria, yeasts, and molds 

maintain freshness by slowing or preventing changes in color, flavor, or texture

adjust flavor

control PH

In all of its food applications, its major use is as a preservative in soft drinks to increase acidity and flavor, and to extend shelf life.

Regulatory process names

Antimol

Benzoan sodny

Benzoate of soda

Benzoate sodium

Benzoic acid, sodium salt

Natrium benzoicum

Sobenate

Translated names

Benzoat de sodiu (ro)

Benzoate de sodium (fr)

Benzoato de sodio (es)

Benzoato de sódio (pt)

Benzoato di sodio (it)

Benzoesan sodu (pl)

Benzoát sodný (cs)

Benzoát sodný (sk)

Benżoat tas-sodju (mt)

Naatriumbensoaat (et)

Natrijev benzoat (hr)

Natrijev benzoat (sl)

Natrio benzenkarboksilatas (lt)

Natriumbensoat (sv)

Natriumbentsoaatti (fi)

Natriumbenzoaat (nl)

Natriumbenzoat (da)

Natriumbenzoat (de)

Nátrium-benzoát (hu)

Nātrija benzoāts (lv)

Sodium benzoate (no)

Βενζοϊκό νάτριο (el)

Натриев бензоат (bg)

IUPAC names

Benzoic acid sodium salt

Benzoic acid, sodiium salt (1:1)

Benzoic acid, sodium salt

Benzoic acid, sodium salt (1:1)

Sodio benzoato

Sodio Benzoato E211

SODIUM BENZOATE

SODIUM-BENZOATE

sodium;benzoate

Trade names

Palmarole Mi.Na.08

SODIO BENZOATO

SODIUM BENZOATE GRANULA

Uses

As a preservative

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.

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. In the U.S., the FDA limits the concentration of a food preservative to 0.1% by weight.

Sodium benzoate is also allowed as an animal food additive at up to 0.1%, per the Association of American Feed Control Officials.

Sodium benzoate has been replaced by potassium sorbate in the majority of soft drinks in the United Kingdom.

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 pharmaceuticals

Sodium benzoate is used to treat urea cycle disorders because it binds to amino acids.

This leads to excretion of these amino acids and a decrease in ammonia levels. 

Sodium benzoate, along with phenylbutyrate, is used to treat hyperammonemia.

Sodium benzoate, along with caffeine, is used to treat postdural puncture headache, respiratory depression associated with overdosage of narcotics, and has been used experimentally with ergotamine to treat vascular headache.

Other uses

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.

Mechanism of food preservation

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 via phosphofructokinase decreases sharply, thereby inhibiting the growth and survival of microorganisms that cause food spoilage.

Health and safety

1909 Heinz advertisement against sodium benzoate

In the United States, sodium benzoate is designated as generally recognized as safe (GRAS) by the Food and Drug Administration.

The International Programme on Chemical Safety found no adverse effects in rats at doses of 647–825 mg/kg of body weight per day.

Cats have a significantly lower tolerance to benzoic acid and its salts than rats and mice.

The human body rapidly clears sodium benzoate by combining it with glycine to form hippuric acid, which is then excreted.

The metabolic pathway for this begins with the conversion of benzoate by butyrate-CoA ligase to the intermediate benzoyl-CoA, which is then metabolized by glycine N-acyltransferase to hippuric acid

Association with benzene in soft drinks and pepper sauces

Main article: Benzene in soft drinks

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.

Most of the beverages that tested above the limit have been reformulated and subsequently tested below the safety limit.

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"), so the observation about beverages applies to pepper sauces containing sodium benzoate, like Texas Pete.