This study investigated the relationship between starch gelatinization, water mobility, and viscosity development in roux-based sauces prepared with wheat flour, rice flour, and potato starch combined with water, milk, or soy milk. We integrated differential scanning calorimetry (DSC), time-domain nuclear magnetic resonance (TD-NMR) relaxometry, and rapid visco analysis to characterize structural changes during roux and sauce preparation. DSC confirmed that starch gelatinization occurred during sauce preparation but not during roux preparation. TD-NMR analysis at 25 °C revealed that potato starch exhibited markedly longer T₂ relaxation times and highest viscosity in water-based systems after cooling from 95 °C, reflecting a loose network with high water mobility. Protein-water interactions in milk and soy milk reduced T₂ values and viscosity (60–70 % reduction) as proteins competed for water. The rice flour-soy milk combination demonstrated a comparable texture to conventional formulations, offering a promising allergen-free alternative for individuals with wheat and dairy allergies.
Shibata-Ishiwatari et al. (Thu,) studied this question.