Umami compounds primarily consist of the amino acid L-glutamic acid (and its salts like MSG) and purine nucleotides such as inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP). These elicit the savory umami taste by activating T1R1/T1R3 receptors. Glutamate is highly water-soluble and occurs naturally in foods like tomatoes, cheese, and seaweed. Nucleotides synergize with glutamate to enhance flavor intensity. They are stable under cooking conditions, non-volatile, and widely used as food additives. GRAS status applies to these compounds in regulated amounts.