Abstract
For determination of thiothiamine in natural foodstuffs two chemical methods other than benzoyl peroxide method which had hitherto been used, have been described. One is an oxidation method by BrCN in an acidic medium and the other a microbiological method using L. fermenti, following conversion of thiothiamine into thiamine by sulfite. Applying these methods, thiothiamine contents in various vegetables were determined. Thiothiamine was detected in onions, Welsh onions, scallions, garlics, cabbages, sprouting cabbages by benzoyl peroxide method. In onions, thiothiamine was determined by benzoyl peroxide, BrCN and microbiological methods with the results agreeing fairly well one another. In scallions, thiothiamine was detected also microbiologically. However, the values were lower than those determined by benzoyl peroxide method, whereas in cabbages thiothiamine was not detected microbiologically. After converting thiothiamine into thiamine by H2O2 treatment, thiothiamine could be detected also in cabbages, but the recovery was poor, possibly due to the decomposition of thiamine by H2O2. The existence of thiothiamine in natural foodstuffs needs further investigations.
