Wikipedia
Disodium inosinate
Disodium inosinate (E631) is the disodium salt of inosinic acid with the chemical formula CHNNaOP. It is used as a food additive and often found in instant noodles, potato chips, and a variety of other snacks. This salt is used as a flavor enhancer made from microbial fermentation growth media that are all-vegetable, usually consisting mainly of tapioca starch. According to the Vegetarian Resource Group Blog, "disodium inosinate-and-disodium guanylate are all vegetable flavor-enhancers"