Abstract
Optimum conditions at lower concentration of NaOH for the thiochrome(Thc) formation from thiamin and 2- (1-hydroxyethyl) thiamin (HET) were studied. Regardless the concentration of K_3Fe(CN)_6 between 0.01% and 0.1%, 5% NaOH gave the highest yield of Thc from thiamin, and the Thc compounds from HET were increased with the decrease of NaOH concentration. In the 5% NaOH, the formation of Thc from each of thiamin and HET was highest and stable around the concentration of 0.025% K_3Fe(CN)_6. And in 21 foods, the values for thiamin and HET of the crude extract agreed well with the values of the conventional extract which is pretreated by a column chromatography. In Green tea and Jute mallow, the colored matters in the crude extract and the unwanted components which were detected after HET by HPLC were removed effectively by using a C_<18> Sep-pak cartridge.
