Studies on sulphur nutrition, flavour and allyl isothiocyanate formation in Brassica juncea (L.) coss. and czern. (brown mustard)

Abstract

AbstractThe effect of sulphate nutrition on vegetative growth of Brassica juncea and on flavour and allyl isothiocyanate development in the seeds has been investigated using plants grown in sand culture in a glasshouse at six concentrations of sulphate in the nutrient medium. Allyl isothiocyanate was determined by the volumetric method of Raquet and the conclusions were confirmed by a semi‐quantitative gas‐chromatographic method. Mean fresh and dry weight of plant tops initially increased steeply with increase of sulphate concentration in the nutrient medium to 0.25 mequiv./l and thereafter tended to increase to an asymptotic maximum. Allyl isothiocyanate content of the seeds showed a similar response to changes in levels of sulphate nutrition. The flavour strength of the seeds also increased with increase of their sulphur content. There were highly significant correlation coefficients between total sulphur concentration in the seeds and their allyl isothiocyanate contents. Possible practical consequences of these observations in the mustard industry are briefly discussed.