Fagopyritols, D-chiro-inositol, and other soluble carbohydrates in buckwheat seed milling fractions

Fagopyritols are mono-, di-, and trigalactosyl derivatives of D-chiro-inosi tol that accumulate in seeds of common buckwheat (Fagopyrum esculentum Moen ch) and may be important for seed maturation and as a dietary supplement. F agopyritols and other soluble carbohydrates were assayed in mature greats a nd 11 milling fractions of common buckwheat seed. Because fagopyritols are in embryo and aleurone tissues, differences in fagopyritol concentrations r eflect varying proportions of these tissues in each milling fraction. Bran milling fractions contained 6.4 g of total soluble carbohydrates per 100 g of dry weight, 55% of which was sucrose and 40% fagopyritols. Flour milling fractions had reduced fagopyritol concentration [0.7 g/100 g of dry weight total fagopyritols in the dark (Supreme) flour and 0.3 g/100 g in the ligh t (Fancy) flours]. Fagopyritol B1 was 70% of total fagopyritols in all mill ing fractions. Fagopyritols were 40% of total soluble carbohydrates in grea ts of two cultivars of common buckwheat but 21% in groats of tartary buckwh eat [Fagopyrum tataricum (L.) Gaertn.], probably a reflection of environmen t and genetics. A rhamnoglucoside present in tartary buckwheat was not dete cted in common buckwheat.