alpha-keto acids and certain precursors and derivatives thereof, particularly those selected from the group which consists of
glyoxylic acid, 2-oxo-
propanoic acid, 2-oxo-butanoic acid, 3-methyl-2-oxo butanoic acid, 3-methyl-2-oxo pentanoic acid, 4-methyl-2-oxo pentanoic acid, 3-hydroxy-2-oxo-
propanoic acid, oxalacetic acid, 2-oxo-
glutaric acid, 2-oxo-3-phenyl-
propanoic acid, 3-(4-hydroxy-phenyl)-2-oxo-propanoic acid, 2-oxo-1H-indole-3-propanoic acid, 2-oxo-1H-
imidazole-4-propanoic acid, 4-methylthio-2-oxo-butanoic acid, 3-mercapto-2-oxo-propanoic acid, 3-hydroxy-2-oxo-butanoic acid, 6-amino-2-oxo-
hexanoic acid and 5-guanido-2-oxo-pentanoic acid, and precursors and derivatives thereof that are capable of being formed from or releasing said acids in the use medium, are useful as flavouring ingredients. Such ingredients are useful for preparing flavouring compositions and a wide variety of flavoured foodstuffs to which they impart greater creaminess and bulkiness so that they have heightened effect in the mouth and generally an enhanced
mouthfeel. They are also useful for enhancing the
sweetness of foods sweetened with natural or artificial sweeteners, and giving it a more natural character.