Viscoelastic properties of rice-corn based gluten free pasta

The incidences of celiac disease are increasing largely due to improved diagnostic procedures and changes in eating habits. Currently, this creates a high demand for high quality gluten-free products, such as gluten-free pasta. Preparation of gluten-free pasta is difficult, as the gluten contributes to a strong protein network that prevents dissolution of the pasta during cooking. Improvement of viscoleastic properties of doughs by incorporation of hydrocolloids to doughs is expected because of the enhanced viscoelastic properties of the polysaccarides. The effect of hydrocolloids on rheological properties of gluten-free dough is related to their molecular structure.The effect of hydrocolloids and proteins on dough rheology in gluten-free formulations based on 60, 80, 100 % gelanized rice and gelatinized corn-gelatinized rice flour mixture were investigated. Hydrocolloids and proteins added at 2% w/w were carboxymethylcellulose (CMC), xanthan gum, guar gum, carrageenan gum, locust bean gum (LBG), casein protein and egg-white. The study on rheological behavior of doughs were performed by Dynamic Mechanical Analyzer (DMA) and Texture Analyzer. The elasticity and resistance to deformation of dough were determined by creep-recovery and dynamic viscoelastic measurments, and the results were modelled by Burger equation. It was found that xhanthan and CMC exhibited the lowest creep compliance values among the added hydrocolloids. They showed the most enhanced elastic properties as evidenced by the highest values of elastic portion of creep compliance. Incorporation of casein increased the elastic behavior of the rice and corn-rice dough.