Studies on the Check of Quality of Japanese Horseradish ('Wasabi') Powder by Gas Chromatography

Part V. An attempt for the practical use of simple checking method of quality by head-space gas chromatography

Abstract

Mustard and horseradish flours and 'Wasabi' powder were investigated by headspace gas chromatography. The Rg (ratio of the peak area of iso-propyl isothiocyanate to that of 3-butenyl isothiocyanate) values of pressed mustard flours and that value of mustard flour prepared with an expeller press were large, but these values of mustard flours made by the extraction with solvent were small.
In horseradish flours, the Rg values of the samples from Hokkaido were large, and that of one from Nagano prefecture was small. The Rg values of these two flours expressed linear relation with the amount of sample for determination. 'Wasabi' powders for experiment were prepared from mixing mustard and horseradish flours in a certain ratio. Rg values of the 'Wasabi' powders were differed by the combination ratios, but the relation between Rg values and combination ratios was shown with a hyperbola curve.
In the hydrolysates of spiceries collected from market, iso-propyl isothiocyanate was not detected. However, the volatile component which had retention time earlier than that of this isothiocyanate was detected. Therefore, whether the spicery was blended in 'Wasabr' powder or not would be distinguished by this method.