Correlation Analysis Between Beverage Apparent Viscosity and Ultrasound Velocity

摘要

Viscosity is an important quality factor for providing food products with quantifiable attributes. A governing law, based on elastic model with the boundary condition of solid particles suspended in liquid, was derived for correlating apparent viscosity with the ultrasound velocity in a liquid food. This law indicates that apparent viscosity varies quadrically with the ultrasound velocity. Experiments were conducted to estimate apparent viscosities of orange and tomato juices using pulse-echo method. The results are in agreement with the governing law proposed. Data analysis demonstrates that the increase of solid particles in the juices increased both the apparent viscosity and ultrasound velocity. This is believed due to the effects of friction between the solid and liquid, and of bulk modulus stiffening.