Rheological and sensory behaviour of rice flour dough: effect of selected additives in relation to dough flattening

The handling of rice flour doughs in terms of sheeting, flattening and rolling is difficult due to the absence of gluten forming proteins; scope exists to improve these characteristics by incorporating appropriate additives during the preparation of rice doughs. Different levels of additives such as whey protein concentrate (WPC) (0-10 %), xanthan gum (0-5 %), sucrose (0-20 %) and salt (0-2 %) have been incorporated, and the rheological (small-deformation oscillation) as well as sensory characteristics have been determined, in addition to microstructural observations and finding inter-relationships. The second order polynomial can adequately explain the rheological parameters like storage modulus, loss modulus and complex viscosity (R = 0.863-0.889, p ≤ 0.01) while it is poor for phase angle (R = 0.659, p ≤ 0.01). Among these additives, xanthan gum imparts the strongest effect (significant at p ≤ 0.01) followed by whey protein concentrate. The effects of these additives are predominantly linear though quadratic effects are also significant in several cases. A cohesive microstructure with improved binding occurs with a high level (7.5 %) of WPC. It is concluded that a judicious selection of additives in appropriate levels can develop rice doughs that possess the desirable handling properties leading to preparation of products.