Buckwheat seed milling fractions: Description, macronutrient composition and dietary fibre

The structure of the mature buckwheat achene and groat is discussed in rela tion to milling fractions and nutritional composition. Whole groats contain 55% starch, 12% protein, 4% lipid, 2% soluble carbohydrates, 7% total diet ary fiber (TDF), 2% ash, and 18% other components (organic acids, phenolic compounds. tannins. phosphorylated sugars, nucleotides and nucleic acids, u nknown corn pounds. The composition of the milling fractions reflects the r elative abundance of seed tissues. Starch is concentrated in the central en dosperm. Protein, oil, soluble carbohydrates and minerals are concentrated in the embryo. Commercial 'Fancy' flour, a light-coloured flour, is mostly central endosperm and contains 75% starch, 6% protein, 1% lipid, 1% soluble carbohydrates, 3% TDF, 1% ash. and 13% other components. Although the embr yo traverses the central endosperm, during milling parts of the embryo sepa rate with the aleurone and seed coat in the bran fraction. Bran, with littl e central endosperm, contains 18% starch, 36% protein, 11% lipid, 6% solubl e carbohydrates, 15% TDF, job ash, and 7% other components. Buckwheat bran also is a rich source of TDF and soluble dietary fibre (SDF), particularly bran with hull fragments (40% TDF of which 25% is SDF), while bran without hull fragments has 16% TDF of which 75% is SDF. (C) 2001 Academic Press.