ABSTRACT
The significance of cereals as dietary sources of phylloquinone (vitamin K1) was estimated by analyzing the phylloquinone content in some representatives of milling and bakery products commercially available in Finland. For extraction of phylloquinone, two procedures were compared. Routine determinations were made by isopropanol-hexane extraction. After purification of the extracts with semipreparative straight-phase HPLC, phylloquinone was quantified by reverse-phase HPLC with dual-electrode electrochemical (EC) detection. Menaquinone-4 (MK-4) was used as an internal standard. The phylloquinone content of some fat-containing bakery products were, however, quantified by the external standard method. The highest phylloquinone content was found in doughnuts (8.5 μg/ 100 g), while the phylloquinone content of other bakery products varied at 3–5 μg/100 g. Among milling products, the best source of phylloquinone was rye meal (5.9 μg/100 g). The phylloquinone content of the other milling products, except whole wheat flour (4.0 μg/100 g), was very low (<3 μg/100 g). Due to this low phylloquinone content, cereal products cannot be regarded as significant sources of vitamin K, despite their overall significance in diets. The contribution to the average daily dietary intake of vitamin K in Finland was estimated to be ≈6 μg, which is 7–10% of the recommended daily intake.
