DETERMINATION OF THE RHEOLOGICAL PROPERTIES OF DOUGH
Rabia Tiryaki, MSc., Bastak Instruments
Food products with wheat as the main raw material are obtained by baking dough formed by water, wheat flour, and other added components and additives depending on the type of wheat flour and product. The rheological properties of dough formed by certain processes from wheat change throughout the processing time, directly affecting the quality of baked products and forming the key to grain chemistry.
The primary gluten-containing protein content in wheat flour is responsible for gas retention, structure formation, and dough strength. Protein content is the most commonly used criterion in determining wheat quality, with the protein content to water absorption ratio changing based on protein quality. The amount of water added to the flour during dough making significantly affects its rheological properties.
Key steps in food processing involving dough formation include kneading, shaping, and fermentation. Physical and chemical changes occur in the dough due to the mechanical force applied during kneading. The kneading process, which largely affects the final product quality, is a crucial parameter in evaluating dough quality.
Dough rheology, encompassing flow and deformation studies, is based on measuring the force exerted during controlled deformation or stress applied to the dough. Rheological analyses provide essential information in the food industry by determining differences in flour qualities, selecting appropriate raw materials, and identifying changes occurring in the dough during fermentation. Particularly in non-Newtonian substances examined with shear stress, determining rheological properties is crucial in baking. The concept of dough rheology, commonly described in doughs with water content ranging from 35% to 55%, includes characteristics such as extensibility, elasticity, resistance, maximum resistance, energy, water absorption, development time, softening degree, and stability, allowing producers to determine how wheat will be processed.
Moreover, obtained rheological data play a critical role in selecting and developing new cultures, quality control in milling and bakery products, detecting the effects of added components in the production process, and process adaptation.
The desired rheological properties vary for different wheat products. Optimum extensibility desired in wheat products varies for each item; for instance, in bread production, high values during the final fermentation stage and early baking are desirable. While bread requires high extensibility and resistance, biscuits require high extensibility with low resistance to avoid collapse after setting during baking.
Bastak brand Absograf 500 and Resistograf 500 devices, critical in determining the rheological behavior of dough and the baking value of flour, are designed with high repeatability, accuracy, ease of use, remote software updates, complying with international standards to directly assess their impact on the final product quality.
Based on measuring the force exerted on device blades due to dough flowability, Bastak's Absograf 500 device analyzes the flour's water absorption, stability, softening value, and development time, meeting world standards and determining its suitability for baking and other products. With ergonomic design and a touchscreen interface, it offers easy usability, remote software support, saving test results as PDFs, storing results via USB flash drive, requiring no computer or screen during testing, and easy cleaning to provide users with an exceptional analysis experience.
The dough obtained following international standards with the Absograf 500 device is first shaped into dough balls in the dough rolling unit of the Bastak brand Resistograf 500 device. Then, in the dough rolling unit, it is shaped cylindrically and left in fermentation chambers at international standard temperatures. Multiple fermentation chambers save time. Utilizing research and development studies, a specialized rail system stretches the dough from bottom to top without the adverse effects of gravity, recording the applied force to obtain a graph. Elasticity, resistance, and energy of the dough are determined according to international standards to achieve ideal bakery products. The touchscreen PC-controlled heating system, parallel testing capability, Absograf 500's touchscreen, manual time control, and compatibility with the Absograf device without requiring a computer or screen allow tracking and saving data on the same touchscreen.
