Supercritical fluid chromatography as a method of analysis for the determination of 4-hydroxybenzylglucosinolate degradation products

In the present study analytical and preparative supercritical fluid chromat ography (SFC) were used for investigation of myrosinase catalysed degradati on of 4-hydroxybenzylglucosinolate (sinalbin). Sinalbin occurs as a major g lucosinolate in seeds of Sinapis alba L., in various mustards and other foo d products. The degradation products were identified and quantified by anal ysis based on a developed SFC method using a bare silica column. Determinat ions comprised transformation products of sinalbin, produced both during de gradation of isolated sinalbin, and during autolysis of meal from S. alba s eeds. The conditions in the developed SFC method were used as basis for the preparative SFC procedure applied for isolation of the components prior to their identification by nuclear magnetic resonance (NMR) spectroscopy. Myr osinase catalysed sinalbin hydrolysis resulted in the reactive 4-hydroxyben zyl isothiocyanate as an initial product at pH values from 3.5 to 7.5 where as 4-hydroxybenzyl cyanide was one of the major products at low pH values. 4-Hydroxybenzyl isothiocyanate was found to disappear from the aqueous reac tion mixtures in a few hours, as it reacted easily with available nucleophi lic reagents. 4-Hydroxybenzyl alcohol was found as the product from reactio n with water, and with ascorbic acid, 4-hydroxybenzylascorbigen was produce d. (C) 2000 Elsevier Science BN. All rights reserved.