Flow behavior of Mexican sauces using a vane-in-a-large cup rheometer

The rheological behavior of six different commercial brands of Mexican sauces was studied. The sauces were considered to be homogeneous with fine particles (“Barbecue”, “Chipotle” and “Valentina”) and heterogeneous with coarse particles (“Taquera”, “Ranchera” and “Verde Búfalo”). The conventional concentric cylinders geometry was used to validate the non-conventional vane-in-cup system. Two containers were tested for the vane-in-cup; a small cup (cup/bob radius ratio = 1.06) and a large cup (cup/bob radius ratio = 2). Rheological parameters were calculated using the Couette–Searle analogy, considering a non-Newtonian behavior and a large cup. The large cup contained eight baffles to avoid slippage at the wall. Homogeneous sauces with fine particles were examined in all fixtures, while the heterogeneous containing coarse particles, only in the vane-in-large cup. All sauces exhibited a shear-thinning behavior that could be correlated by the power-law model. Several shear stress and shear rate factors proposed in the literature for large gaps and power-law models were compared to the average shear factors proposed in this study. The method proposed here was proved to be an alternative to characterize the flow properties of coarse particles suspensions in a vane-in-a-large cup rheometer.