E634 - Calcium 5'-ribonucleotide

At a glance

This additive is used to lift savory flavor.

• Role: flavor enhancer that strengthens umami taste
• Typical use: savory seasonings, soups, sauces, snack coatings
• Often paired with: monosodium glutamate (MSG) for synergy
• Label names: “E634,” “calcium 5'-ribonucleotide,” or “calcium 5'-ribonucleotides”
• Regulatory status: authorized in the EU with conditions on use levels and categories
• Dietary notes: a calcium-based alternative to sodium ribonucleotides

Why is Calcium 5'-ribonucleotide added to food?

Food makers add E634 to intensify savory, umami taste and to round off the overall flavor profile; it is classified as a flavor enhancer in EU law.¹ It is commonly used together with glutamate sources such as monosodium glutamate because ribonucleotides (inosinate and guanylate) and glutamate reinforce each other’s umami impact.²

What foods contain Calcium 5'-ribonucleotide?

You’ll most often see E634 in savory products where a fuller, longer-lasting taste is desired. Examples include:

• Dry soup mixes, bouillons, and instant noodles
• Savory snacks and seasoning blends
• Sauces, gravies, marinades, and spice rubs

These uses are consistent with its functional class as a flavor enhancer in international standards, which list many savory food categories where 5'-ribonucleotides may be used.³ On labels, look for “E634,” “calcium 5'-ribonucleotide(s),” or pairing with E621, disodium 5'-ribonucleotide, disodium inosinate, or disodium guanylate.

What can replace Calcium 5'-ribonucleotide?

Alternatives depend on the recipe and dietary goals:

• Other ribonucleotides: disodium 5'-ribonucleotide, disodium inosinate, disodium guanylate, or their calcium counterparts calcium inosinate and calcium guanylate.
• Glutamate sources: monosodium glutamate or glutamic acid.
• Label-friendly approaches: yeast extracts and umami-rich ingredients (e.g., mushroom powders), recognizing they may have different labeling and flavor profiles.

How is Calcium 5'-ribonucleotide made?

E634 is the calcium salt mixture of two 5'-ribonucleotides—5'-inosinate (IMP) and 5'-guanylate (GMP). In practice, manufacturers neutralize the corresponding acids with a calcium base to form the calcium salts and blend them in defined proportions.⁴ Its identity and purity specifications (e.g., assay range, limits for impurities) are set out in EU additive specifications.⁴

Is Calcium 5'-ribonucleotide safe to eat?

Within the European Union, E634 is authorized as a flavor enhancer and may be used only in the foods and at the levels laid down in the Union list of food additives.¹ Internationally, the Codex General Standard for Food Additives includes INS 634 in its flavor enhancer class with permitted uses across a range of savory categories, which are adopted by many regulators globally.³ As with most flavor enhancers, it is intended for use at low levels needed to achieve the desired taste effect.¹

Foods for infants and young children are subject to special rules in the EU, and additive permissions in those categories are more restrictive than for general foods; businesses must follow the specific conditions and exclusions in the Union list.¹

Does Calcium 5'-ribonucleotide have any benefits?

Its main benefit is sensory: it deepens savory flavor and enhances umami, especially when used alongside glutamate sources such as MSG.² This synergy means a small amount can noticeably improve the impact of seasonings, soups, and sauces.²

Who should avoid Calcium 5'-ribonucleotide?

• Infants and young children: EU rules for these foods are more restrictive; manufacturers must observe the specific permissions and exclusions for additives in these categories.¹
• Anyone following a personal or medical avoidance plan for flavor enhancers should check labels and consult a healthcare professional.

Myths & facts

• Myth: “It’s the same as MSG.”
  Fact: E634 is a mixture of calcium salts of 5'-ribonucleotides (IMP and GMP). MSG is a glutamate salt. They are different ingredients, though they’re often used together for umami.

• Myth: “It always adds sodium.”
  Fact: E634 is calcium-based. Sodium versions of ribonucleotides exist (for example, E627, E631, and E635), but E634 itself does not add sodium by design.

• Myth: “It creates meaty flavor on its own.”
  Fact: Ribonucleotides mainly boost and round out savory notes that are already present. They work best in combination with glutamate-rich ingredients.

Calcium 5'-ribonucleotide in branded foods

On ingredient lists, look for “E634,” “calcium 5'-ribonucleotide,” or “calcium 5'-ribonucleotides.” It often appears in the small-print part of the label, sometimes alongside E621, E631, or E627. You’ll most commonly find it in savory snack seasonings, bouillon cubes, instant soups, noodles, gravies, and spice blends.

References

Footnotes

1. Regulation (EC) No 1333/2008 on food additives — Union list and general conditions of use. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008R1333 ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Questions and Answers on Monosodium Glutamate (MSG) — U.S. FDA (notes use of inosinate/guanylate with MSG). https://www.fda.gov/food/food-additives-petitions/questions-and-answers-monosodium-glutamate-msg ↩ ↩² ↩³

3. Codex GSFA (INS 634) — Calcium 5'-ribonucleotides, functional class and food categories. https://www.fao.org/gsfaonline/additives/details.html?id=229 ↩ ↩²

4. Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008 (includes E 634). https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩²