Rheological characterisation of almost intact and stirred yogurt by imperfect squeezing flow viscometry

摘要: Samples of plain yogurt two national brands, almost intact and after stirring for 1 min by hand with a domestic blender, were placed in wide shallow TeflonR container. They subsequently compressed plate to induce imperfect lubricated ‘squeezing flow’. The recorded force versus height relationships plotted on logarithmic co-ordinates. resulting curves all had clear linear part indicating the region where squeezing flow was dominant. Its slope order −1.2 −1.3 specimens −0.5 −0.9 stirred samples. test reproducibility, expressed terms coefficient variation (100σ/x) about 15% more than sufficient detect textural differences between brands monitor changes caused stirring. These apparent compressive stress at preselected heights (1 2 mm) residual relaxation times (60 120 s). flowability samples also elongational viscosity biaxial strain rate relationships. All these mechanical parameters modest dependence upper diameter but latter no effect their sensitivity as measures consistency. © 1999 Society Chemical Industry