Volatile compounds associated with the off-flavour in stored casein

Summary Compounds associated with the ‘gluey’ off-flavour in stored casein have been isolated and identified by a combination of gas chromatography and mass spectrometry. Most of the flavour was found in the non-acid steam-volatile fraction which contained many compounds including n-alkanals, n-alkan-2-ones, furfural and other furan derivatives, benzaldehyde, dimethyl disulphide and benzthiazole. No single compound had the typical gluey flavour, which must be a complex sensation in which the quantities of minor components may determine the specific gluey character. o-Aminoacetophenone was present in the casein in subthreshold amounts. This compound has some gluey flavour and may have a synergistic effect in enhancing the total flavour.