Disodium guanylate (E627), the disodium salt of guanosine 5'-monophosphate, is a white crystalline powder employed as a potent umami flavor enhancer in processed foods. It occurs naturally in dried mushrooms, fish, and yeast extracts and is produced industrially via microbial fermentation. When combined with monosodium glutamate and disodium inosinate it exhibits strong synergistic taste intensification. The compound is stable under typical food-processing conditions, non-volatile, and contributes no aroma of its own. Regulatory bodies classify it as generally recognized as safe (GRAS) for direct addition to food at levels consistent with good manufacturing practice.