Studies on Oat Starch with a Celloscope: Granule Size and Distribution

Detailed granule size distribution in oat starch was determined with a Celloscope. Maximum granule number appeared at a diameter range of 1.9-2.4 μm and corresponding maximum volume was at 6.0-7.6 μm. In light of the observed high reproducibility of the Celloscopic technique it was concluded that no aggregation of individual granules occurred at concentrations below 1 mg/ml. The Celloscopic data based on direct counting of granules as a function of their shape-independent volume. It could be demonstrated that two different average granule sizes, 3.0 and 6.4 - 7.4 μm, can be obtained depending on whether the sizings are based on estimation of the granule's cross-sectional areas or directly the effective volumes. Only the latter approach was capable of revealing variety-specific differences in the average granule masses. For rapid starch sizings of samples containing granules from any of the size ranges within the distribution diagram a rapid “coarse” counting method was developed.