Ultrasound measurements for determining rheological properties of flour-water systems

Automation of the food industry requires fast and reliable measurements of the physical properties of materials during processing. The mixture of wheat flour, water, yeast and other ingredients produces a dough with specific viscoelastic characteristics capable of retaining gas and producing aerated goods. Within the baking industry, the control of dough properties is required to achieve final product quality and consistency. Traditional methods for dough testing are slow and off-line and do not provide fundamental rheological information. There is therefore a need for the development of fast and on-line instruments capable of providing relevant data for baking. Ultrasonics provides a nondestructive, rapid and low cost technique for the measurement of physical food characteristics. In this work, the rheological properties of dough are investigated using ultrasonic techniques. The measurements are correlated with dough quality tests. A common protocol for dough preparation is used for each type of measurement. Experimental results on different flour quality, water content and dough processing are presented. The relationship between measured ultrasonic parameters and final product quality is discussed.