Calcium diglutamate, sometimes abbreviated CDG and also called calcium biglutamate, is a compound with formula Ca(C5H8NO4)2. It is a calcium acid saltofglutamic acid. CDG is a flavor enhancer (E number E623)—it is the calcium analog of monosodium glutamate (MSG). Because the glutamate is the actual flavor-enhancer, CDG has the same flavor-enhancing properties as MSG but without the increased sodium content.[1] Notably, only the L isomer is used in flavouring as D-glutamate does not have an umami/savoury flavour.[2][3]
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| Names | |
|---|---|
| IUPAC name
Calcium bis[(2S)- 2-amino-4-carboxy-butyrate] | |
Other names
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| Identifiers | |
 Y | |
3D model (JSmol) |
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| Abbreviations | CDG, CBG |
| 11158966 | |
| ChemSpider |
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| ECHA InfoCard | 100.025.307 
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| E number | E623 (flavour enhancer) |
PubChem CID |
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| UNII |
Y |
CompTox Dashboard (EPA) |
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| Properties | |
| C10H16CaN2O8 | |
| Molar mass | 332.322 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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As a soluble source of calcium ions, this chemical is also used as a first-aid treatment for exposure to hydrofluoric acid.[4]
Calcium di-glutamate can be prepared by reacting calcium carbonate with two molar equivalents of glutamic acid:[5]
Concentration of the solution to a syrup under reduced pressure, followed by gradual crystallisation, affords the monohydrate.[5] Structurally, the glutamate anion is zwitterionic, with the amino group protonated (pKa = 9.47) and both carboxylic-acid groups (pKa = 2.10, 4.07) in their deprotonated carboxylate form.[6]
Calcium di-L-glutamate can be used to prepare other glutamates through metathesis with a soluble sulfate, carbonate or hydroxide salt. For example, manganese(II) di-L-glutamate can be prepared through metathesis with manganese(II) sulphate:[7]