Biaxial extensional viscosity in wheat flour dough during baking

• Published in: Journal of food engineering Vol. 236; pp. 29 - 35
• Main Authors: Vanin, F.M., Lucas, T., Trystram, G., Michon, C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2018; Elsevier
• Subjects: Biaxial extensional viscosity; Environmental Sciences; Lubricated squeezing flow; Physical chemistry; Relaxation; Rheology; Temperature; Viscoelasticity; Viscoelasticity; Relaxation; Temperature; Biaxial extensional viscosity; Rheology; Physical chemistry; Lubricated squeezing flow; STRAIN HARDENING; BIAXIAL EXTENSIONAL VISCOSITY; LUBRICATION; STRAIN HARDENING EFFECTS; LUBRICATED SQUEEZING FLOW; EFFECT OF TEMPERATURE; RHEOLOGY; PHYSICAL-CHEMICAL REACTION; RELAXATION; VISCOSITY; VISCOELASTICITY; ELASTICITY; SQUEEZING FLOW; PHYSICAL CHEMISTRY; TEMPERATURE; FLOW BEHAVIOUR INDEX; VISCOELASTIC LIQUID; EXTENSIONAL VISCOSITY
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2018.05.007

Lubricated squeezing flow (LSF) experiments on wheat flour dough were conducted at a constant biaxial extensional rate followed by relaxation experiments. The effect of temperature on the rheology of the dough was studied in the range 25–95 °C under small and large strain to characterize changes in the dough through a possible pathway to simulate the dough-crumb transition during the first step of the baking process. A strain hardening effect was shown over the whole temperature range. Like extensional viscosity measured at 0.1 and 0.65 biaxial strain, the consistency index (K) decreased from 25 °C to 45 °C and increased at temperatures above 50 °C. Two levels of the behaviour index (n) were found: 0.35–0.40 below 45 °C, and 0.1–0.2 above 45 °C. The relaxation degree also changed dramatically but only at higher temperatures (56–60 °C), below which it remained almost constant (98-99%), once the dough became a viscoelastic liquid, above this temperature the main physical-chemical reactions (starch and protein) started to occur, leading to more solid properties. These results complement those of LSF. LSF experiments at large biaxial strain (0.75), combined with a relaxation experiment, were successfully used for dough/crumb characterisation at a temperatures ranging from 25 °C to 74 °C. Alpha values estimated from Launay's model were incorporated in the flow behaviour index, underwent the same type of changes as a function of temperature as n but with a less marked transition; n was divided by two and K increased by about one decade. •Physico chemical properties of wheat flour doughs evolve greatly with temperature.•The first step of baking could be model using a rheometer.•Wheat flour dough rheological properties were characterized in a larger gap conditions.•Gluten thermosetting and starch gelatinisation contributions are followed.