Abstract:Raw starch granules of mature mungbean (Vigna radiata L. cv. KPS1) seeds were prepared by two methods into crude and cesium chloride (CsCl)-washed forms. The purity, shape, size distribution, and associated protein profiles were examined. The appearance of raw starch granules showed a bimodal type distribution in which average granules had typical ovoid shapes, whereas the small ones were spherical. Abnormal granule surface with distinct tumor-like or dented hole features were also observed in raw starch granules. CsCl-washed granules had a smooth surface compared to that of the crude form. The granule size distribution ranged from 6−35 μm; most 15−25 μm (53%), followed by 25−35 μm (26%). Small granules (<15 μm) amounted to 18%, and granules >35 μm consisted of 3%. The two forms were further refined by trichloroacetic (TCA) treatment to reveal surface proteins on the crude granules or tightly bound proteins on CsCl-washed granules. In the washed-refined granules, only a few integral proteins were retained. The major 58-kDa protein was identified to be granule-bound starch synthase I by sequence homology with that in cowpea (Vigna unguiculata) and maize (Zea mays) using MALDI-TOF mass and Mascot search.