Vitamin B6 and pyridoxine glucoside content of wheat and wheat flours

Analysis of different wheats and flours for vitamin B6 using water extracts and reverse-phase high-performance liquid chromatography revealed significant variation in content of pyridoxine (PN) and pyridoxine glucoside (PNG), a glycosidic adduct of B6 with partial human bioavailability found in many plant foods. Other vitameric forms of vitamin B6 were not detected. In 22 American and Canadian wheats total vitamin B6 (the sum of PN plus PNG observed in samples) content varied over a threefold range of 3.4 to 11.1 nmol/g. PNG accounted for a significant portion of the variation (1.9-8.8 nmol/g), with less variation in PN (0.9-2.7 nmol/g). Mean values (+/- standard deviations) were 5.0 +/- 1.8 nmol/g for total vitamin B6; 1.7 +/- 0.5 nmol/g for PN; and 3.4 +/- 1.8 nmol/g for PNG. American hard wheats contained significantly more vitamin B6, mostly as PNG, compared to Canadian hard wheats. The same pattern was seen for Colorado hard wheats compared to others. Hard wheats contained more vitamin B6 than did soft wheats. Flours milled from 16 of the cultivars contained approximately 75% less B6 than did the corresponding wheats