EFFECT OF WHEAT-FLOUR AGING ON STARCH-GRANULE SURFACE-PROTEINS

Prime starch was isolated from aged wheat flours by acetic acid extrac tion (pH 3.5). Starch-granule surface proteins were extracted from the se starch samples with 1% sodium dodecyl sulfate (SDS) containing 1% 2 -mercaptoethanol at room temperature (15-25-degrees-C) and quantified by the Lowry method. The amount of starch-granule surface proteins fro m aged flours was three to four times greater than the control samples . The SDS-polyacrylamide gel electrophoresis pattern of these extracte d starch-granule surface proteins was different between the control an d aged samples. High-performance liquid chromatography clearly showed that the higher molecular mass proteins (22-150 kDa) increased with ag ing of the wheat flour.