Disodium inosinate
Disodium inosinate (E631) is a flavour enhancer used with MSG in crisps, instant noodles and stock cubes. It is the ribonucleotide most often made from fish or meat rather than by fermentation, and EU labels are not required to say which — the single most common reason vegans query an E-number.
Disodium inosinate is the sodium salt of inosinic acid, a nucleotide originally isolated from dried bonito flakes. Like guanylate it has little taste alone and works by multiplying the umami effect of glutamates, so it is almost always listed beside E621.
It can be produced by fermenting plant starch or extracted from fish or meat, and EU labelling does not require the source to be declared. That ambiguity — not any safety question — is why it appears so often in vegan and halal ingredient queries. EFSA set a group acceptable daily intake for the ribonucleotides in 2021.
On the label
- E-number
- E631
- INS number
- INS 631
- Functional class
- Flavour enhancer
- Also known as
- Sodium inosinate · Flavour enhancer 631 · INS 631 · IMP
Frequently asked questions
It depends on the source. It is produced either by fermentation of plant starch or by extraction from fish or meat. Inosinate is the ribonucleotide most often associated with a fish source (traditionally dried bonito), and the label never says which was used — ask the manufacturer if it matters to you. The same applies to a vegetarian diet.
Yes — the additive itself contains no gluten. A gluten-free claim belongs to the finished product, though — check the pack, not the additive.
It is produced either by fermentation of plant starch or by extraction from fish or meat, and EU labelling does not require the source to be declared — so the E-number alone cannot answer this. A halal certification mark on the finished product, or the manufacturer directly, is the only reliable signal.
EFSA re-evaluated the ribonucleotides in 2021 and set a group acceptable daily intake. Like other purines it metabolises to uric acid, so people managing gout are sometimes advised to limit it, though flavour-enhancer quantities are small next to dietary purines from meat and fish.