310 Small granule starches from wheat, amaranth and quinoa as components for novel biodegradable two- phase compounds.

E. C. WILHELM, H. Themeier, H. Mack, and M. G. Lindhauer. Institute for Cereal, Potato and Starch Technology, Federal Centre for Cereal, Potato and Lipid Research, (BAGKF) D32756 Detmold, Germany.

A small technical scale process for the separation and refinement of small granule starches from wheat, amaranth and quinoa was developed based on modern starch technology, adapted conventional machinery and technical enzymes to save the thermal-dry stability and the whiteness of the starches. The functional properties of these smallest native starch granules (0.5–3.0 µm) were investigated for novel applications in starch-compound products and compared to those of purified small granule wheat starch (3–6 µm) fractionated from the industrial B-starch line, technically available in large quantities. In a project of BAGKF Detmold and IKT University Stuttgart sponsored by the Federal Ministry Bonn, novel extrusion compounding processes were investigated to form two-phase compounds from small granule starches and synthetic polymers requiring starch structures with high thermal stability. Investigations on the biodegradability of starch compounds were carried out in the aqueous system with an inoculum of activated sludge by determination of the carbon dioxide. As a surprising synergism effect the small granule starch compounds based on polyurethanes, polycaprolactones or polylactic acid showed a significantly higher biodegradability of the synthetic polymer in the compounds, activated by the small granule starch degradation.