Shear Flow Behavior of Aqueous Suspensions of Potato Parenchyma Powder

Abstract

The shear flow behavior of potato powder suspensions prepared from two different particle sizes and with a range of solids volume fraction (Φ) was studied. A concentrated sucrose solution was used as the continuous phase to maintain particle buoyancy. The shear flow properties were measured at 20, 50 and 80 °C. The suspensions obeyed a power-law equation in the dilute regime while the Herschel-Bulkley equation was the best fit for almost all semi-dilute and more concentrated suspensions. With increasing Φ, particle size and temperature, a gradual development of shear-thinning behavior was evident which coincided with an increase in the consistency index and the development of a yield stress in the suspensions. Potato powder suspensions therefore behave very differently to potato starch suspensions, with flow properties dominated by the effect of intra- and inter-cellular components in the potato powder particles that are transferred to the continuous phase and that alter suspension properties.