Effect of temperature and concentration on rheological properties of beetroot juice

The rheological behaviour of beetroot juice as a function of soluble solid content (from 10oBx to 50oBx) at a wide range of temperatures (from 10oC to 60 oC) was studied. The measurements were made using rotational rheometer (Brookfield Engineering Laboratories: model LVDV-II+ PRO). The investigation showed that the beetroot juice was Newtonian in behaviour and the viscosity was changed from 0.77 mPa s to 28.4 mPa s. The Arrhenius-Guzman equation was used to calculate the values of flow activation energy. In order to evaluate the influence of soluble solid content two models were applied: the power law and exponential equation. A new equation was proposed to express the combined effect of temperature and concentration on beetroot juice viscosity.