Wheat Flour Enriched with Calcium and Inulin: A Study of Hydration and Rheological Properties of Dough

The aim of this work was to study the effect of calcium (Ca) carbonate-inulin (In) systems on hydration and rheological properties of wheat flour dough. Wheat flour, Ca carbonate from 108 to 252 (mg Ca/100 g flour) content, and enriched In oligofructose at levels of 1% to 13% (flour basis), were used. Hydration dough properties were researched analyzing water absorption (W abs), moisture content (M cont), water activity (a w), and relaxation time (λ). W abs and a w decreased with increasing In levels independently of Ca content. Dough development time increased with the amount of Ca. In the presence of In, samples with the lowest content of Ca were those showing the highest development time values. Inulin was the main component that controled W abs in dough. In the presence of CaCO3, although water seemed to be in a free state according to the high a w value measured (>0.975), the low value of relaxation time obtained suggests less molecular mobility. Rheological properties of dough were studied by texture, relaxation, and viscoelasticity assays. Dough hardness and consistency significantly increased with Ca and mainly with In content. At high In content, dough texture was enhanced by CaCO3 due to the fact that this salt could behave as dough strengthener. Adhesiveness of dough was not modified by CaCO3 at low In levels. However, Ca affected adhesiveness at intermediate In levels. Adhesiveness was significantly increased by In presence. Calcium and In both diminished dough cohesiveness. The In presence increased dough elasticity, independently of Ca content. A second-order polynomial model and response surface methodology were used for studying hydration dependence and rheological parameters (R 2 > 0.771) on Ca and In. Dough M cont varied with In2 and mainly inversely proportional to In. An inverse dependence of λ on In was detected. Dynamic and relaxation elastic moduli (G′ and E 3) showed a linear dependence on In.