Investigations into flavouring compounds formed in roasted brown mustard (Brassica juncea Linn.)

Roasted brown mustard seeds (Brassica juncea LINN.) form an important condiment. Whereas the flavour of unroasted mustard seed powder is mainly due to isothiocyanates, their roasting brings about changes in its flavour. Twenty four compounds have been identified in roasted mustard which are responsible for its flavour, these include nine carbonyls, six pyrazines, two thiophenes, two amines, one nitrile, two isothiocyanates, one thiocyanate and one alkyl sulphide. The carbonyls were resolved as 2,4‐DNP‐hydrazones by TLC. The quantity of total carbonyls per 5 kg in roasted mustard was 105 mg as compared to 26 mg in unroasted mustard. Non‐carbonyls were separated both by GLC and TLC. By GLC these were characterised by their specific retention times on different columns and on TLC by their R and specific colour reactions. They were further confirmed by their IR spectra. Their quantitative estimation and mechanism of formation is discussed.