Micro-Scale Shear Kneading—Gluten Network Development under Multiple Stress–Relaxation Steps and Evaluation via Multiwave Rheology

Abstract

To evaluate the kneading process of wheat flour dough, the state of the art is a subsequent and static measuring step on kneaded dough samples. In this study, an in-line measurement setup was set up in a rheometer based on previously validated shear kneading processes. With this approach, the challenge of sample transfer between the kneader and a measurement device was overcome. With the developed approach, an analysis of the dynamic development of the dough is possible. Through consecutive stress–relaxation steps with increasing deformation, a kneading setup in a conventional rheometer is implemented. Fitting of the shear stress curve with a linearization approach, as well as fitting of the relaxation modulus after each kneading step, is a new way to evaluate the matrix development. Subsequently, multiwave rheology is used to validate the kneading process in-line. The shear kneading setup was capable of producing an optimally developed dough matrix close to the reference kneading time of 150 ± 7.9 s (n = 3). The linearization approach as well as the power-law fit of the relaxation modulus revealed gluten network development comparable to the reference dough. With this approach, a deeper insight into gluten network development and crosslinking processes during wheat flour dough kneading is given.

Strain-dependent assessment of dough’s polymer structure and functionality during the baking process

“…During the heating steps, normal force control was activated (F N = 0.01 N), whereas the gap was kept constant during the measurement intervals. Measurements were conducted every 5˚C at a frequency of 1 Hz and a deformation of 0.05% at a fixed measurement time of 25 s. The deformation was applied as multiwave strain according to Vidal et al (2022) [23], enabling the simultaneous measurement of multiple frequencies within a single measurement point. Besides the fundamental frequency of 1 Hz, harmonics being the 2 nd , 3 rd , 5 th , 7 th , 8 th and 10 th multiple of the fundamental frequency, were performed simultaneously.…”

“…Furthermore, the implementation of multiwave oscillatory shear rheological techniques favor the measurement of yeasted dough samples. Applying multiwave rheology, more information can be extracted out of a reduced measurement time [ 22 , 23 ]. This is beneficial for accessing the time-dependent functionality of dough during fermentation and temperature-dependent behavior during the baking process.…”

Microscopic analysis of gluten network development under shear load—combining confocal laser scanning microscopy with rheometry

“…To produce shear kneaded dough in the MCR502 rheometer (Anton Paar, Ostfildern, Germany), a plane plate‐cylinder geometry setup with 25 mm diameter of the upper plate geometry and 25.1 mm inner diameter of the cylinder was used. For all experiments, 192 mg of flour and demineralized water stained with rhodamine B (Merck KGaA, Darmstadt, Germany), 0.01 g/100 mL water were kneaded in the rheometer according to Vidal et al (2022). The sample preparation is shown in Figure 2.…”

“…These interruptions are the state-of-the-art to evaluate the dough matrix at different stages of development on a microstructural level. To isolate energy transfer from the complex kneading geometries of most commercial kneaders, Vidal et al (2022) developed a microscale kneading process that uses only shear to develop a dough matrix. Analyzing the evolving protein network in gluten-starch systems and wheat flour doughs on a microscale using a confocal laser scanning microscope (CLSM) is already state-of-the-art in cereal science.…”

“…diameter of the cylinder was used. For all experiments, 192 mg of flour and demineralized water stained with rhodamine B (Merck KGaA, Darmstadt, Germany), 0.01 g/100 mL water were kneaded in the rheometer according toVidal et al (2022). The sample preparation is shown in Figure2.…”