Some physicochemical properties of small-, medium-, and large-granule starches in fractions of waxy barley grain

Barley grain was divided into eight fractions from the surface layer to the center with a machine used to polish brewers' rice. Small-, medium-, and large-granule starches were isolated from classified barley flour, and their physicochemical properties were investigated. The starch granules were oval to round with a median size of 2 mu m for small, 10 mu m for medium, and 12-19 mu m for large granules. From the surface layer to the center, both the median sizes and the ratio of large granules decreased, and the ratio of medium- and small-granules increased. The starches had A-type X-ray diffraction patterns typical of cereal starches. The moisture sorption showed a negative correlation to the granule size. The gelatinization temperatures of starch granules in each layer were approximately the same, but the enthalpies decreased in the order of large, medium, and small granules.