Potassium sorbate

Potassium sorbate^[1][2]

Names
IUPAC name Potassium (2E,4E)-hexa-2,4-dienoate
Other names E202 Sorbistat-K Sorbistat potassium
Identifiers
CAS Number	24634-61-5
ChEBI	CHEBI:77868
ChemSpider	4445644
Jmol interactive 3D	Image
KEGG	D02411
PubChem	23676745
InChI InChI=1S/C6H8O2.K/c1-2-3-4-5-6(7)8;/h2-5H,1H3,(H,7,8);/q;+1/p-1/b3-2+,5-4+; Key: CHHHXKFHOYLYRE-STWYSWDKSA-M InChI=1/C6H8O2.K/c1-2-3-4-5-6(7)8;/h2-5H,1H3,(H,7,8);/q;+1/p-1/b3-2+,5-4+; Key: CHHHXKFHOYLYRE-ZCSOUONQBI
SMILES [K+].[O-]C(=O)\C=C\C=C\C
Properties
Chemical formula	C6H7KO2
Molar mass	150.22 g·mol^−1
Appearance	White crystals
Odor	yes
Density	1.363 g/cm^3
Melting point	270 °C (518 °F; 543 K) (decomposes)
Solubility in water	58.5 g/100 mL (100 °C)
Solubility in other solvents	Soluble in ethanol, propylene glycol Slightly soluble in acetone Very slightly soluble in chloroform, corn oil, ether Insoluble in benzene
Hazards
NFPA 704	1 2 0
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	4340 mg/kg (oral, rat)[3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Potassium sorbate is the potassium salt of sorbic acid, chemical formula CH₃CH=CH-CH=CH-CO₂K. It is a white salt that is very soluble in water (58.2% at 20 °C). It is primarily used as a food preservative (E number 202).^[4] Potassium sorbate is effective in a variety of applications including food, wine, and personal care products. While sorbic acid is naturally occurring in some berries, virtually all of the world's production of sorbic acid, from which potassium sorbate is derived, is manufactured synthetically.

Production

Potassium sorbate is produced industrially by neutralizing sorbic acid with potassium hydroxide. The precursor sorbic acid is produced in a two-step process via the condensation of crotonaldehyde and ketene.^[5][6][7]

Uses

Potassium sorbate is used to inhibit molds and yeasts in many foods, such as cheese, wine, yogurt, dried meats, apple cider, soft drinks and fruit drinks, and baked goods.^[8] It is used in the preparation of items such as maple syrup and milkshakes served by fast food restaurants such as McDonalds.^[9][10] It can also be found in the ingredients list of many dried fruit products. In addition, herbal dietary supplement products generally contain potassium sorbate, which acts to prevent mold and microbes and to increase shelf life. It is used in quantities at which there are no known adverse health effects, over short periods of time.^[11] Labeling of this preservative on ingredient statements reads as "potassium sorbate" or "E202". Also, it is used in many personal care products to inhibit the development of microorganisms for shelf stability. Some manufacturers are using this preservative as a replacement for parabens. Tube feeding of potassium sorbate reduces gastric burden of pathogenic bacteria.^[12]

Also known as "wine stabilizer", potassium sorbate produces sorbic acid when added to wine. It serves two purposes. When active fermentation has ceased and the wine is racked for the final time after clearing, potassium sorbate will render any surviving yeast incapable of multiplying. Yeast living at that moment can continue fermenting any residual sugar into CO₂ and alcohol, but when they die no new yeast will be present to cause future fermentation. When a wine is sweetened before bottling, potassium sorbate is used to prevent refermentation when used in conjunction with potassium metabisulfite. It is primarily used with sweet wines, sparkling wines, and some hard ciders but may be added to table wines which exhibit difficulty in maintaining clarity after fining.

Some molds (notably some Trichoderma and Penicillium strains) and yeasts are able to detoxify sorbates by decarboxylation, producing piperylene (1,3-pentadiene). The pentadiene manifests as a typical odor of kerosene or petroleum.^[13]

Toxicology

Pure potassium sorbate is a skin, eye and respiratory irritant.^[14]

Typical culinary usage rates of potassium sorbate are 0.025% to 0.1% (see sorbic acid), which in a 100 g serving yields an intake of 25 mg to 100 mg. The maximum acceptable daily intake for human consumption is 25 mg/kg, or 1750 mg daily for an average adult (70 kg).^[11][15] Under some conditions, particularly at high concentrations or when combined with nitrites, potassium sorbate has shown genotoxic activity in vitro.^[15]

Although some research implies it has a long-term safety record,^[16] in vitro studies have shown that it is both genotoxic and mutagenic to human blood cells. Potassium sorbate is found to be toxic to human DNA in peripheral blood lymphocytes, and hence found that it negatively affects immunity.^[17] It is often used with ascorbic acid and iron salts as they increase its effectiveness but this tends to form mutagenic compounds that damage DNA molecules.^[18] Regardless, three studies have not found it to have any carcinogenic effects in rats.^[19][20][21]

See also

• Sodium benzoate

References

1. Merck Index, 11th Edition, 7661.
2. Potassium sorbate at Sigma-Aldrich
3. http://chem.sis.nlm.nih.gov/chemidplus/rn/590-00-1
4. Nordic Food Additive Database Nordic Working Group on Food Toxicology and Risk Assessment
5. Erich Lück, Martin Jager and Nico Raczek "Sorbic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, 2011, Wiley-VCH, Weinheim. doi:10.1002/14356007.a24_507.pub2
6. patent process for commercial potassium sorbate
7. CFNP TAP Review
8. Erich Lück, Martin Jager and Nico Raczek "Sorbic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2000.doi:10.1002/14356007.a24_507
9. "Ingredients - Vanilla Mc Shake". McDonalds USA. Retrieved 24 April 2014.
10. "Nutrition Information". Mc Donalds UK. Retrieved 24 April 2014.
11. "036. Sorbate, potassium (FAO Nutrition Meetings Report Series 40abc)". Inchem.org. Retrieved 2013-02-22.
12. Tulamait, Aiman; Laghi, Franco; Mikrut, Kathleen; et al. (2005). "Potassium sorbate reduces gastric colonization in patients receiving mechanical ventilization". J Crit Care 20 (3): 281–287. doi:10.1016/j.jcrc.2005.03.002. PMID 16253799.
13. The Soft Drinks Companion - A technical handbook for the beverage industry, Chapter 10
14. "Potassium Sorbate" (PDF). Chem One, Ltd. 2010-06-14. Retrieved 2015-05-04.
15. Carocho, Márcio; Barreiro, Maria Filomena; Morales, Patricia; Ferreira, Isabel C.F.R. (2014). "Adding Molecules to Food, Pros and Cons: A Review on Synthetic and Natural Food Additives". Comprehensive Reviews in Food Science and Food Safety 13 (4): 377–399. doi:10.1111/1541-4337.12065.
16. Tulamait, Aiman; Laghi, F; Mikrut, K; Carey, RB; Budinger, GR (2005). "Potassium sorbate reduces gastric colonization in patients receiving mechanical ventilization". J Crit Care 20 (3): 281–287. doi:10.1016/j.jcrc.2005.03.002. PMID 16253799.
17. Mamur, Sevcan; Yüzbaşıoğlu, Deniz; Ünal, Fatma; Yılmaz, Serkan (2010). "Does potassium sorbate induce genotoxic or mutagenic effects in lymphocytes?". Toxicology in Vitro 24 (3): 790–4. doi:10.1016/j.tiv.2009.12.021. PMID 20036729.
18. Kitano, K; Fukukawa, T; Ohtsuji, Y; Masuda, T; Yamaguchi, H (2002). "Mutagenicity and DNA-damaging activity caused by decomposed products of potassium sorbate reacting with ascorbic acid in the presence of Fe salt". Food and Chemical Toxicology 40 (11): 1589–94. doi:10.1016/S0278-6915(02)00119-9. PMID 12176085.
19. Hendy, R J; Hardy, J; Gaunt, I F; Kiss, I S; Butterworth, K R (1976). "Long-term toxicity studies of sorbic acid in mice". Food and Cosmetics Toxicology 14 (5): 381–86. doi:10.1016/S0015-6264(76)80173-3. PMID 1010505.
20. Gaunt, I F; Butterworth, K R; Hardy, J; Gangolli, S D (1975). "Long-term toxicity of sorbic acid in the rat". Food and Cosmetics Toxicology 13 (1): 31–45. doi:10.1016/0015-6264(75)90080-2. PMID 1123201.
21. Mason, P L; Gaunt, I F; Hardy, J; Kiss, I S; Butterworth, K R; Gangolli, S D (1976). "Long-term toxicity of parasorbic acid in rats". Food and Cosmetics Toxicology 14 (5): 387–94. doi:10.1016/S0015-6264(76)80174-5. PMID 1010506.