Correlation Analysis Between Beverage Apparent Viscosity and Ultrasound Velocity

Abstract

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.

Rheological Characteristics of Carob Pekmez

“…[1] Furthermore, rheological characteristics of pekmez are of particular interest in the design of flow processes, standardization, product development, quality control, and unit operations as it provides information on its physical characteristics. Viscosity, an important quality factor for providing food products with quantifiable attributes, [7] is also considered an important physical characteristic related to the quality of liquid food products. [8] There is a number of research works published about rheological [1,9,10] and chemical properties of grape pekmez [2,3,11,12,13,14] and mulberry pekmez.…”

Foreign Body Detection in Foods Using the Ultrasound Pulse/Echo Method

“…The pressure ratios in the cases of juices with FB (Table 3) are smaller than those of water (Table 2). This may be due to: (1) impedances of juices may be larger than that of water (Zhao et al. 2003), which decrease the difference ( z 4 − z 3 ), and (2) the attenuations of juices can not be neglected.…”

Low intensity ultrasound

“…In some cases viscosity may correlate strongly with composition (e.g., sugar syrups) but in most cases the dependence of longitudinal ultrasonic velocity on the shear modulus of a fluid is extremely weak and direct viscosity measurement problematic. A more physically sound approach using longitudinal wave measurements depends on the damping of the oscillations (and hence acoustic losses) of small particles suspended in a fluid (Herrmann & McClements, 1999;Zhao, Basir, & Mittal, 2003b). If the fluid is flowing under known pressure, the position and velocity of entrained scattering particles can be measured by the ultrasonic Doppler effect.…”