Calcium 5'-ribonucleotides

Calcium 5'-ribonucleotides is a mixture used as a flavor enhancer food additive. It listed as E number reference E634. This food additive is banned in Australia and New Zealand.^[1] Calcium 5'-ribonucleotides are special compounds that come from breaking down RNA. They consist of a sugar called ribose, a phosphate group, and a calcium ion attached to the nucleotide. These compounds are important for improving the taste of food, especially when combined with substances like MSG. They work by interacting with specific receptors on our taste buds, known as calcium-sensing receptors (CaSR). This helps to make flavors taste stronger and richer. Because of their ability to enhance taste without adding extra salt or artificial flavor enhancers, calcium 5'-ribonucleotides are useful in creating more flavorful foods. The umami taste is perceived as a savory taste found in foods such as meat and cheese.

Chemical structure of calcium guanylate, one of the components of calcium 5'-ribonucleotides

Calcium 5'-ribonucleotides Pathway

Calcium 5′-ribonucleotides like inosine monophosphate (IMP) and guanosine monophosphate (GMP) help make umami taste stronger when combined with glutamate, such as in MSG (monosodium glutamate).^[2] On their own, these compounds don’t taste very strong, but when they’re present with glutamate, they boost the taste significantly. This effect is known as synergism and is a key part of how the body detects umami flavor.^[2] This process starts when glutamate and a 5′-ribonucleotide bind to the specific G-protein couple receptors known as the T1R1/T1R3 taste receptor on the tongue.^[2] This forms a heterodimer and activates a signaling pathway inside the taste cell starting with the activation of a G-protein called Gα-gust.^[2] This triggers the enzyme phospholipase Cβ2 to produce inositol trisphosphate (IP3) and diacylglycerol (DAG).^[2] The production of IP3 leads to the release of calcium ions from storage, raising the calcium concentration in the cell.^[2] This increase in calcium triggers the opening of ion channels and the release of neurotransmitters, such as ATP, which then travel to the brain through nerve signals.^[2]These neurotransmitters play a key role in transmitting the umami taste sensation to the brain.