Calcium citrate
Structural formula | ||||||||||||||||||||||
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Surname | Calcium citrate | |||||||||||||||||||||
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Molecular formula | C 12 H 10 Ca 3 O 14 | |||||||||||||||||||||
Brief description |
white, odorless solid |
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properties | ||||||||||||||||||||||
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Physical state |
firmly |
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solubility |
very bad in water (850 mg l −1 at 18 ° C) and ethanol |
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Calcium citrate , the calcium salt of citric acid , is a white, odorless, tasteless, crystalline solid .
Extraction and presentation
It is produced by neutralizing citric acid using a calcium source such as calcium hydroxide . In this exothermic precipitation reaction , four molecules of water (" crystal water ") are bound per part of calcium citrate .
- Calcium hydroxide and citric acid react to form tricalcium dicitrate and water.
Analogous to this reaction equation, calcium citrate is an intermediate product in the production of citric acid from citrus fruits .
properties
Calcium citrate contains around 21% calcium , based on the molar mass of the tetrahydrate C 12 H 10 Ca 3 O 14 · 4 H 2 O. The water solubility increases with decreasing temperature (inverse solubility ) and decreasing pH value . Due to the higher solubility as compared with inorganic calcium salts such as calcium carbonate or calcium phosphate that is bioavailability of calcium citrate contained in the calcium higher.
use
In addition to the long-known positive influence of calcium on bone density (see osteoporosis ), recent studies show that with a sufficient calcium intake, the risk of overweight and obesity also decreases. For these reasons, calcium citrate is added to foods for calcium fortification and used for dietary supplements ( functional food ). But it is also used as an acidity regulator and stabilizer and in pharmaceuticals , feed and dental care products. It is approved in the EU as a food additive with the number E 333 .
Occurrence
Calcium citrate was found in the deep-sea sediments of the Weddell Sea in the form of the very rare mineral earlandite .
Individual evidence
- ↑ Entry on E 333: Calcium citrates in the European database for food additives, accessed on June 27, 2020.
- ↑ Entry on CALCIUM CITRATE in the CosIng database of the EU Commission, accessed on February 24, 2020.
- ↑ a b Calcium citrate data sheet (PDF) from Merck , accessed on January 19, 2011.
- ↑ Entry on calcium citrate. In: Römpp Online . Georg Thieme Verlag, accessed on June 19, 2014.
- ↑ a b Data sheet Calcium citrate tribasic tetrahydrate, ≥98.0% (calc. On dry substance, KT) from Sigma-Aldrich , accessed on October 22, 2016 ( PDF ).
- ↑ Earlandite: Earlandite mineral information and data
literature
- Römpp chemical dictionary. 9th edition. (Editor: Falbe / Regitz), p. 553.
- Kurt Schreier, Hans Wolf: Studies on the influence of citric acid on calcium metabolism. In: European Journal of Pediatrics. Vol. 67, No. 5, 1950, pp. 526-544.
- HJ Heller, LG Greer, SD Haynes, JR Poindexter, CY Pak: Pharmacokinetic and pharmacodynamic comparison of two calcium supplements in postmenopausal women. In: Journal of Clinical Pharmacology . Vol. 40, 2000, pp. 1237-1244.
- KM Davies, RP Heaney, RR Recker et al: Calcium intake and body weight. In: The Journal of Clinical Endocrinology & Metabolism . Vol. 85, no. 12, 2000, pp. 4635-4638.
- RP Heaney, KM Davies, MJ Barger-Lux: Calcium and weight: clinical studies. In: Journal of the American College of Nutrition. Vol. 21, No. 2, 2002, pp. 152S-155S
- SJ Parikh, JA Yanovski: Calcium intake and adiposity. In: American Journal of Clinical Nutrition. Vol. 77, No. 2, 2003, pp. 281-287.
- MA Pereira, DR Jacobs, Jr., L. Van Horn, ML Slattery, AI Kartashov, DS Ludwig: Dairy consumption, obesity, and the insulin resistance syndrome in young adults: the CARDIA Study. In: JAMA . Vol. 287, no. 16, 2002, pp. 2081-2089.
- MB Zemel, H. Shi, B. Greer, D. Dirienzo, PC Zemel: Regulation of adiposity by dietary calcium. In: Faseb Journal . Vol. 14, 2000, pp. 1132-1138.