RHEOLOGY OF STARCH PASTES FROM STARCHES OF DIFFERENT ORIGINS - APPLICATIONS TO STARCH-BASED SAUCES

Starches of four types, from maize (normal, or chemically modified, wa xy), wheat (unmodified) and rice (waxy, unmodified), have been investi gated under different pasting conditions. The effect of the upper past ing temperature which is known to be of particular importance in the f unctional properties of starch in industrial processes has been specif ically investigated. The rheological properties have been assessed fro m viscosity measurements (flow behaviour) at 60 degrees C. Gel propert ies upon cooling the paste were estimated through viscoelastic measure ments in oscillatory shear. The main objective was to evaluate the eff ect of thermal treatment on the textural characteristics of a bechamel sauce, taken as a model of starch-based sauces, and prepared with the same starches in similar pasting conditions. Overall, the differences noticed in the flow and viscoelastic properties of the different star ches were also found in the bechamel sauces formulated with the same s tarches. (C) 1998 Academic Press.