Quantitative comparison of volatile flavor compounds in deep-roasted and light-roasted sesame seed oil

The effect of roasting degree on the formation of volatile compounds in sesame seeds was investigated. Light-and deep-roasted sesame seed oils were steam distilled under reduced pressure, and volatiles from the distillate were separated by an adsorptive column method. The recoveries of total volatiles were 9726 and 2014 ppb from deep-and light-roasted oils, respectively. The relative amount of monoalkylpyrazines decreased in contrast to the increases of di- and trialkylpyrazines with increase in the degree of roasting. 1H-Pyrrole-2-carboxyaldehyde, the most abundant pyrrole, was the only volatile that decreased in deep-roasted oil. 4,5-Dimethylisothiazole, 4,5-dimethylthiazole, 2-propyl-4-methylthiazole, and 2-butyl-5-methylthiazole increased their relative amounts in deep-roasted oil. Hexanal, (E)-2-heptenal, and (E,E)-2,4-decadienal occurred in almost the same levels. Guaiacol and 2-furanmethanethiol increased from 32 to 321 ppb and from 6 to 40 ppb, respectively, in deep-roasted oil.