Structural Properties of the Starches Isolated from Developing Waxy Rice Seeds

Abstract:

In this study，waxy rice starches（WRS） were isolated from the developing waxy rice seeds that were harvested at pollination stage for 11，13，15，17，22，27，and 35 days. The structural properties，including the shape，the crystallites，and molecular structure，were studied to find the change law of starch structure during pollination stage. The results，obtained from scanning electron microscope（SEM） and laser particle size analyzer（LPSA），showed that the spherically immature starch particles gradually disappeared and powder particle size of the peak increased from 5.92 μm to 6.77 μm. The XRD data indicated that the relative crystallinity increased from 31.0% to 37.5% during pollination stage. Molecular structure analysis suggested that the weight-average molecular weight（Mw） and the number-average molar mass（Mn） were the higher for the increased side chain during later pollination stage. WRS isolated from later pollination stage was easier to gather together after gelatinization.