Disodium 5'-ribonucleotides or I+G, E number E635, is a flavor enhancer which is synergistic with glutamates in creating the taste of umami.
[1] Disodium 5'-ribonucleotides were first assessed in 1974 by the Joint FAO/WHO Expert Committee on Food Additives based on all available scientific literature.
[2] This essentially means that this additive shows no toxicology at any level and acceptable daily limits do not need to be set.
The definition is as follows: This statement means that, on the basis of available data (chemical, biochemical, and toxicological), the total daily intake of the substance arising from its use or uses at levels necessary to achieve the desired effect and from its acceptable background in food, does not, in the opinion of the Committee, represent a hazard to health.
For this reason, and for reasons stated in the individual evaluations, the establishment of an acceptable daily intake (ADI) expressed in mg per kg of body weight is not deemed necessary.In 1993, the Joint FAO/WHO Expert Committee on Food Additives considered several more studies on this food additive and retained the "ADI not specified" safety classification.