Calcium citrate
683071
220786692
2008-06-21T15:59:47Z
DOI bot
6652755
Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]].
{{Chembox new
| Name = Calcium citrate
| ImageFile = Calcium_citrate.PNG
| ImageSize =
| ImageName = Calcium citrate
| IUPACName = 2-hydroxy-1,2,3-propane- tricarboxylic acid calcium salt (2:3)
| OtherNames = E333
| Section1 = {{Chembox Identifiers
| SMILES = C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])O.<br />C(C(=O)[O-])C(CC(=O)[O-])(C(=O)[O-])O.<br />[Ca+2].[Ca+2].[Ca+2]
| CASNo = 813-94-5
| EINECS = 212-391-7
}}
| Section2 = {{Chembox Properties
| Formula = Ca<sub>3</sub>(C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>)<sub>2</sub>
| MolarMass = 498.46 g/mol (anhydrous)
| Appearance = White powder
| Density = 1.63 g/cm<sup>3</sup>, solid
| Solubility = 0.095 g/100 ml (25 °C)
| MeltingPt = 120 °C (loses water)
| BoilingPt = Decomposes
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://physchem.ox.ac.uk/MSDS/CA/calcium_citrate.html External MSDS]
| MainHazards = Irritant
}}
| Section8 = {{Chembox Related
| OtherCations = [[Sodium citrate]]
| OtherCpds =}}
}}
'''Calcium citrate''' is the [[calcium salt]] of [[citric acid]]. It is commonly used as a [[food additive]] ([[E number|E333]]), usually as a [[preservative]], but sometimes for [[flavor]]. In this sense, it is similar to [[sodium citrate]]. Calcium citrate is also used as a [[water softener]] because the citrate ions can [[chelate]] unwanted metal ions. Calcium citrate is also found in some dietary calcium supplements.
==Chemical properties==
Like citric acid, calcium citrate has a [[sour]] taste. Like other salts, however, it also has a salty taste. For this reason, citrates such as sodium and calcium citrate are commonly known as ''sour salt''.
==Production==
Calcium citrate is an intermediate in the isolation of citric acid from the fermentation process by which citric acid is produced industrially.<ref>{{Cite web|url=http://www.lime.org/ENV02/Other802.htm|title=Use of Lime in the Chemical Industry|accessdate=2006-11-25|publisher=National Lime Association}}</ref> The citric acid in the broth solution is neutralized by [[calcium hydroxide]], precipitating insoluble calcium citrate. This is then filtered off from the rest of the broth and washed to give clean calcium citrate.
The calcium citrate thus produced may be sold as-is, or it may be converted to citric acid using dilute sulfuric acid.
==Biological role==
Calcium supplements, e.g. as calcium citrate, may increase aluminium toxicity.<ref>{{cite journal | title = Role of calcium in aluminium toxicity | author = Zdenko Rengel | journal = [[New Phytol.]] | volume = 121 | pages = 499–513 | year = 1992 | doi = 10.1111/j.1469-8137.1992.tb01120.x}}</ref> Patients with renal disease are at an increased risk of toxicity.
[[Bioavailability]] is 2.5 times higher than [[calcium carbonate]]. For this reason, patients who have undergone the [[Roux-en-Y]] variety of weight-loss surgery (also known as [[gastric bypass]]) are usually instructed to take calcium citrate as a dietary supplement.
==References==
<references/>
[[Category:Citrates]]
[[Category:Calcium compounds]]
[[Category:Salts]]
[[ar:سترات كالسيوم]]
[[de:Calciumcitrat]]
[[es:Citrato de calcio]]
[[it:Citrato di calcio]]
[[hu:Kalcium-citrát]]
[[pt:Citrato de cálcio]]