Granule Size and Distribution of Raw and Germinated Oat Starch in Solid State and Ethanol Solution

The morphology and granular properties of oat starch during germination were investigated by scanning electron microscopy and X-ray powder diffractometer. The granule size distribution of oat starch was studied in various concentrations in ethanol using a laser particle-size analyzer. The starch granule shape before germination remained almost the same after germination, as shown by low-magnification (x1000) scanning electron microscopy. However, surface fissures at high-magnification (x5000) were found on the sample at the end of germination. After soaking, the relative crystallinity of the samples significantly reduced, by following increased and then decreased, reaching a maximum crystallinity of 16% at the end of germination. In various ethanol concentrations, the size of starch granules produced in different germination phase slightly varied, but this difference was not easy to detect in the scanning electron microscope x1000 images. Overall, the particle size of oat starch generally decreased and the specific surface area increased significantly during oat germination.