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

Addition of incompatible components into starch-containing foods may lead to self-aggregation of starch gel. Increase in compatibility between amylomaize starch and guar gum by forming sucrose-ester complex was investigated by changes in glass transition temperature (Tg). Differential scanning calorimetry revealed Tg for the amylomaize-guar gum mixture at 66.7°C, which was close to the Tg of guar gum at 68.4°C, however, the Tg of amylomaize was disappeared. Also, the complex-guar gum no longer displayed the Tgs of two individual components, and exhibited a significantly different Tg at 80.4°C. Similarly, dynamic mechanical analysis showed new Tgs at 92.2 and 104.5°C for the amylomaize-guar gum and the complex-guar gum mixtures, respectively. Although the Tgs of individual the components were still appeared in the above mixtures, the heights of tan delta peaks declined. Above evidence implies that interaction, which led to close contact between two components' molecules in each mixed gel, decreased the volume fraction of the relaxing phase. Both were partially compatible with guar gum, however, the complex manifests higher compatibility than the corresponding amylomaize. All the samples exhibited sub-Tgs and sub-Tg endotherms below the corresponding Tgs. These indicated a further evidence of side-chain relaxation of compatible polymers.