Flow behaviour of goats milk yoghurts and bioyoghurts

Flow behaviour of yoghurts and bioyoghurts produced from goat’s unconcentrated milk at using different starter cultures was compared. Four starter cultures were applied to the production of yoghurts and four to the production of bioyoghurts too. Rheological properties were examined using rotary viscometer Rheotest 2 with controlled shear rate in coaxial cylinders system. Flow curves of yoghurts and bioyoghurts were assigned and described by Ostwald de Waele, Herschel-Bulkley and Casson models. An apparent viscosity was counted for shear rate 3 s-1. Generally, higher viscosity of yoghurts in comparison to bioyoghurts was stated. The yoghurts were generally characterised by higher value of consistency coefficient K and yield stress than bioyoghurts. The yoghurts have shown likewise higher deviation from Newtonian flow (lower values of exponent n) than bioyoghurts.