The Department of Nutrition, Dietetics, and Food Sciences has just acquired a state-of-the-art rheometer. The AR-G2 rheometer from TA Instruments in placed in room 326 and is ready to be used. One of the most useful parameters that can be measured with the rheometer is viscosity. The viscosity of food materials can be correlated to the thickness and the consmer acceptance of the product. When you analyze your product for viscosity and/or when you are looking for reformulation strategies, these are a couple of tips that can help you achieve your goal.
Viscosity is usually affected by:
- Particle size: If the total mass of particles in a suspension is kept constant, but the particle size of the solid phase is reduced, then viscosity increases
- Volume fraction: Viscosity usually increases with an increase in volume fraction
- Particle size distribution: The borader the particle size distribution for any volume fraction of solids, the lower the viscosity
- Zeta potential: For systems with small particles (< 1 micron), viscosity increases with increasing zeta-potential.
Other parameters that can be measured with the rheometer are the storage modulus (G’), the loss modulus (G”), and the phase shift angle (δ). For more information about all the different application of rheology in foods, please refer to “Rheology Methods in Food Process Engineering” by Dr. Steffe.
