INFLUENCE OF EXTRACTION ON THE DETERMINATION OF VITAMIN-B-6 IN FOOD BY HPLC

The effect of the extraction procedure on the total vitamin B-6 conten t in different food matrices is presented. The use of hydrochloric aci d, sulphuric acid and trichloroacetic acid, combined with enzymatic hy drolysis using several commercial enzyme preparations, was tested. The results of two liquid chromatographic methods (isocratic and gradient elution) and those of microbiological assay were compared. Reproducib le results were achieved using a mineral acid followed by beta-glucosi dase/acid phosphatase hydrolysis for extraction of the same sample and only a few unknown compounds caused interference in the reversed-phas e chromatogram However, the conversion efficiency of the enzyme prepar ation should always be checked. The liquid chromatographic method indi cated that there was a higher vitamin content compared with the microb iological assay. This is probably due to a lower growth response of Sa ccharomyces with pyridoxamine and pyridoxal rather than pyridoxine.