The Biopolymer Network Limited, has been developing the Al-Hakkak Process, a commercially viable process to isolate biopolymer fractions from starchy materials such as cereals. These biological resources contain biopolymers that can be used to produce safe, natural and biodegradable products. This extraction process results in the generation of several product streams of varying composition, functionality and commercial value.

The work reported here focused on drying a fraction containing starch granules. Scanning Electron Microscopy (SEM) was used to investigate the effect of variations in the extraction/washing and drying processes on the differences in the structure and arrangement of dried oat starch granules, isolated using a pilot scale Al-Hakkak Process. The purpose of these investigations was to gain insight into the effect of varying upstream process parameters on the resulting dried oat starch powder. Visual assessment of the SEM images successfully identified differences in structure and arrangement of the oat starch granules as a result of extraction and drying processes.

This work has provided evidence that both extraction and drying affected the structure and arrangement of the oat starch granules after drying. Depending on the processing conditions, spray drying produced robust, roughly spherical, tightly packed, oat starch granule agglomerates. Acidic conditions during settling enhanced the formation of these roughly spherical, oat starch granule agglomerates, whereas washing the oat starch granules to remove the soluble fraction lessened their formation. Milling the dried oat starch was observed to cause significant damage to individual oat starch granules, evident as fractured and broken granules.