The invention relates to flavor compositions and pet food products containing the same. A flavor composition comprising at least one nucleotide derivative and/or at least one transmembrane compound that modulates, increases and/or enhances the activity of an umami receptor is provided that can be used to enhance the umami taste and/or palatability of food products. In certain, non-limiting embodiments, the flavor composition comprises at least one nucleotide derivative and/or at least one transmembrane compound, optionally at least one nucleotide, optionally at least one first amino acid, optionally at least one second amino acid.