In this paper, we investigated the effect of test conditions such as probe diameter, compression distance, trigger force, container volume, pre-test speed, test speed, post-test speed on the textural properties of stirred yoghurt, and we also evaluated the effect of pre-test speed, test speed, post-test speed on the firmness, elasticity and viscosity of yoghurt with an orthogonal experimental design L9(34). In addition, the textural properties, viscosity and elastic modulus of 8 kinds of popular commercial yogurt were in situ determined without destroying the original packaging. The results showed that all test conditions affected the textural properties of stirred yoghurt. The appropriate test conditions were as follows: 1 mm/s of pre-test speed and test speed, 10 mm/s of post-test speed, 30 mm of compression distance, 35 mm of probe diameter, 5 g of trigger force, and 100 mL of container volume. At the confidence level of α = 0.05, test speed had a significant effect on the firmness and elasticity, while post-test speed was a significant factor influencing the adhesive force. Moreover, there existed obvious differences in the textural properties of different kinds of yoghurt. Elastic modulus was correlated with firmness, consistency, adhesiveness, adhesive force and elasticity, and viscosity was correlated with firmness, consistency, adhesiveness and adhesive force.

Propylene glycol alginate is widely used in dairy products or milk-based beverages as a thickener.The aim of the work was to study the influence of pH on the rheological properties of propylene glycol alginate solution.For this purpose,steady-state flow sweep,strain sweep,frequency sweep,dynamic viscoelasticity temperature sweep and dynamic viscosity temperature sweep experiments were carried out with an AR-G 2 rheometer.The experimental results showed that the viscosity,viscoelasticity,and complex viscosity of propylene glycol alginate solution decreased as pH increased,while the loss tangent increased.Meanwhile,at pH below 7 the degree of shear thinning decreased while it increased at pH above 7.In addition,pH influenced the effect of temperature on the viscosity and viscoelasticity of propylene glycol alginate solution.

Oat flour is widely used in beverage after being processed as a kind of grain. In this paper, pasting properties of starch from oat flour were studied using a rapid viscosity analyzer (RVA). Meanwhile, oat gluten was also characterized by measuring ethanol solubility index and the protein properties were determined using dilute lactic acid. The effects of different production processes for oat flour on pasting properties of starch and viscosity characteristics of gluten protein were discussed. We also determined the content of β-glucan in oat flour, which was found to have no obvious effect on the viscosity of gluten protein measured using dilute lactic acid. In addition, the peak viscosity and final viscosity measured using dilute lactic acid had obvious correlations with the final viscosity obtained from the method of ethanol solubility index showing correlation coefficients of 0.810 3 and 0.836 4, respectively, but no correlation with ethanol solubility index was observed.