Effect of starch granule size distribution and elevated amylose content on durum dough rheology and spaghetti cooking quality

To obtain an indication of the effect of increasing the starch amylose content above normal levels (27-74%) and increasing the percentage of B-type starch granules (11-60%) on durum dough properties and the quality of the spaghetti derived from these doughs, the reconstitution approach was used. Reconstituted flours were prepared from a common Wollaroi gluten, solubles and tailings fraction combined with starches containing varying B-granule contents, or with starches from maize with varying amylose content. An increased B-granule content increased farinograph water absorption. Cooked spaghetti firmness was highest with B-type granules at 32-44% (volume percentage basis), which is approximate to 10-15% higher than normally found in durum starch. Increasing the amylose content in the starch caused the dough to be more extensible, increased spaghetti firmness, and decreased water absorption with optimum quality of amylose at 32-44%. The information indicates there would be benefit in producing durum wheats with slightly elevated B-granule and amylose contents.