2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

The apparent viscosities of mixed starch-polysaccharide gum solutions by Rapid Viscosity Analyzer were investigated on five native starches and ten polysaccharide gums. The resultant viscosity ratios of the mixtures to pure gum solutions and their starch concentration dependencies were compared with respect to the granular property of starches and the molecular property of polysaccharide gums. Generally, when non-gelatinized starches that only swell in the solutions were used, the viscosity increment with increasing starch concentration (0-20%) was greater for the polysaccharide gums with higher dependencies of viscosity on gum concentration (i-carrageenan, konjac flour, CMC and HM-pectin) than for those with the lower dependencies (l-carrageenan, xanthan gum, locust bean gum, guar gum and sodium alginate). Wheat starch and the starches with high swelling abilities (waxy corn and potato) played significant roles for the front and latter gums systems, respectively. When completely gelatinized starches were analyzed instead, the starch concentration dependencies in viscosity and viscosity ratio greatened to 9-20 times of the corresponding data in case of non-gelatinized starches. Such increments varied with the polysaccharide gum concentration change (in continuous phases) due to the exclusion effect of swollen granules (as dispersed phases) and the molecular entanglements in these phases. The potential molecular entanglements in the composite solutions related to the structural feature of the samples concerned.