by Jeanne Yacoubou, MS
VRG Research Director
A reader wrote to The VRG in March 2011 stating that he had heard that disodium guanylate was sourced from fish. He asked us to look into it.
Disodium guanylate, known by many names including disodium 5’-guanylate, is derived from a nucleotide, guanosine monophosphate (GMP). It is similar to disodium inosinate, also known as disodium 5’-inosinate, which comes from another nucleotide, inosine monophosphate (IMP). The two together are frequently referred to as 5’-nucleotides (read as “five prime nucleotides.”) Nucleotides are naturally occurring substances found mostly in meats although shiitake mushrooms are also high in nucleotides. Nucleotides are components of information-carrying molecules (such as DNA) as well as important molecules involved in many diverse aspects of human metabolism.
In the flavor industry, disodium inosinate and disodium guanylate are commonly known as disodium ribotides (“I + G.”) It is typically sold in a 50:50 mixture of the two ribotides. It is the I + G in combination with glutamates (naturally occurring from glutamic acid, an amino acid found in proteins) which imparts the umami (i.e., savory or meaty) flavor to foods. Only very small amounts are needed to yield a very savory taste sensation.
A small amount of I + G may be added to a food to replace some monosodium glutamate (MSG). (MSG is itself used to reduce the salt, or sodium chloride, content of a food while providing a meaty flavor due to its glutamate content.) The effect of this addition is to impart a magnification of the savory taste sensation by enhancing a food’s natural flavors. The overall result is even less sodium chloride in the final product. One manufacturer’s quality assurance manager told us that “actually [food companies] can use one of them, either disodium inosinate or disodium guanylate [to get the flavor enhancement], but they usually use both of them.” In fact, disodium guanylate is responsible for stronger flavor enhancement than is disodium inosinate.
The VRG spoke to three leading manufacturers of disodium guanylate and disodium inosinate about these common flavor enhancers. All of them reported that they produce I + G by microbial fermentation. Their growth media are all-vegetable, usually consisting mainly of tapioca starch.
The Ajinomoto product of disodium inosinate and disodium guanylate is called “Ajitide I + G.” The process was described as one in which the “nucleoside precursors” of disodium inosinate and disodium guanylate are first produced by microbial fermentation. After further processing, the end products are the nucleotides, GMP and IMP. These nucleotides are then separated from the fermentation medium, purified and crystallized. The nucleotides are approved by the United States Food and Drug Administration (FDA) for food use. “The product does not contain animal products…” according to company documents.
One of our sources in the regulatory affairs department of her company that produces I + G from yeast stated that since they are flavor products of a natural process, “they can be labeled [on a food package] as ‘natural flavors.’ There’s no need to list them as ‘disodium inosinate’ or disodium guanylate.’”
A manufacturer of hydrolyzed vegetable protein (HVP) told us that when his company adds disodium inosinate (as a flavor enhancer) to a TVP product that he sells to another company, it is clearly stated on his label. He did not know, however, if his buyer, by federal regulation, must state on the label of the final food product that disodium inosinate is present. Interested readers may wish to inquire with food companies if they have questions about the “natural flavors” or the “flavor enhancers” used in food products but which may or may not appear as an ingredient on the label.
I + G is usually used in conjunction with monosodium glutamate (MSG), yeast extracts, and/or HVP. In the yeast extracts and HVP, their glutamates combine with salt present in the food to form MSG. The glutamates also combine with I + G to produce a greater savory taste. In many cases, a synergistic flavor profile results which means the resulting savoriness is more than the sum of each component’s contribution to the taste if used separately. I + G, MSG, HVP and yeast extracts are often used in soups, sauces, and seasonings as well as in fast food and packaged rice or noodle premixes. I + G may also be used alone to enhance flavor as long as the food item is high in natural glutamates (tomatoes, Parmesan cheese, etc.)
The use of all these ingredients, by themselves or in some combination, usually permits the reduction of the total sodium chloride (salt) content of the packaged premix or prepared food while enhancing the food’s salty and savory flavors.
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The contents of this website and our other publications, including Vegetarian Journal, are not intended to provide personal medical advice. Medical advice should be obtained from a qualified health professional. We often depend on product and ingredient information from company statements. It is impossible to be 100% sure about a statement, info can change, people have different views, and mistakes can be made. Please use your best judgment about whether a product is suitable for you. To be sure, do further research or confirmation on your own.