Journal ofCereal Science 33 (2001) 271–278 doi:10.1006/jcrs.2001.0366, available online at http://www.idealibrary.com on Buckwheat Seed Milling Fractions: Description, Macronutrient Composition and Dietary Fibre K. J. Steadman∗, M. S. Burgoon∗†, B. A. Lewis†, S. E. Edwardson‡ and R. L. Obendorf∗§ ∗ Cornell University Seed Biology, Department of Crop and Soil Sciences, Cornell University Agricultural Experiment Station, Ithaca, NY 14853-1901, U.S.A.; † Cornell University Division of Nutritional Sciences, Ithaca, NY 14853, U.S.A.; ‡ Minn-Dak Growers Ltd, P. O. Box 13276, Grand Forks, ND 58208-3276, U.S.A. Received 10 May 2000 ABSTRACT The structure of the mature buckwheat achene and groat is discussed in relation to milling fractions and nutritional composition. Whole groats contain 55% starch, 12% protein, 4% lipid,2% soluble carbohydrates, 7% totaldietary fiber (TDF), 2% ash,and 18% other components (organic acids, phenolic compounds, tannins, phosphorylated sugars, nucleotides and nucleic acids, unknown com- pounds). The composition of the milling fractions reflectsthe relative abundance of seed tissues. Starch is concentrated in the central endosperm. 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 embryo traverses the central endosperm, during milling parts of the embryo separate with the aleurone and seed coat in the bran fraction. Bran, with little central endosperm, contains 18% starch, 36% protein, 11% lipid, 6% soluble carbohydrates, 15% TDF,7% 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.  2001 Academic Press Keywords: ash,bran,buckwheat, dietary fibre, Fagopyrum esculentum, flour,lipid, milling fractions, nutritional composition, protein, soluble carbohydrates, starch. enes)are generally roasted (called kasha). Groats INTRODUCTION are also milled into various gradesof flour,the Common buckwheat (Fagopyrum esculentum Mo- mostcommon ofwhich islightflour,consisting ench, Polygonaceae) is an under-utilised grain mainly ofstarchy central endosperm. Lightflour crop.Its seeds are used in many forms in foods is used in buckwheat pancakes, breads and soba particularly popular in Japan, Russia, and Central noodles.Hull (pericarp) is removed from buck- and Eastern Europe. Whole groats (dehulled ach- wheatseeds by impact milling and the resulting groat(or the intactachene) is roller-milled and the product sifted to remove the fragmented hull 1 .  :AOAC=Association ofOfficial Buckwheat seed milling fractions contain various AnalyticalChemists;IDF=Insoluble dietaryfibre; proportionsofcentralendosperm, embryo,and NDF=neutraldetergent fibre;SDF=soluble dietary maternal tissues, each of which are very different fibre;TDF=total dietary fibre. in composition. The embryo and aleurone, the § Corresponding author: Tel +1-607-255-1709; Fax +1-607- 255-2644; E-mailrlo1@cornell.edu living tissues in a viable mature dry buckwheat 0733–5210/01/030271+08 $35.00/0  2001 Academic Press