Cereal Chem 52:24r - 41r.  |  VIEW ARTICLE
Dough Rheology at Large Deformations in Simple Tensile Mode.

V. F. Rasper. Copyright 1975 by the American Association of Cereal Chemists, Inc. 

Modified extensigraph with variable hook speed and strain gage recording system and Universal testing machine (Instron) with special cross-head attachment were used for stress-strain studies on doughs at different extension rates in simple tensile mode. A higher accuracy of stress-strain curves obtained by Universal testing machine even at very low values of strain made it possible to interpret them in terms of isochronal constant strain rate modulus F(t*), and exponent n characterizing the time dependence of the time dependent constant strain rate modulus F(t). The sensitivity and practical significance of these two parameters were demonstrated on doughs prepared from chemically treated flours and mixtures of wheat flour and wheat starch as well as wheat flours supplemented with vital gluten. At strain values lambda-1 greater than 1.5, extensigraph and Instron stress-strain curves were similar and could be easily transformed into deformation curves. Coefficients of absolute viscosity derived from the deformation curves over the shear stress range of 158-2,510 kg.m-1.s-2 were between 10(5) and 10(6) g.cm-1.s-1.