How does viscosity affect dairy products?

In the world's dairy products, due to the large consumption, the corresponding rheological research is also more extensive. Studies have shown that the rheological properties of milk are influenced by its concentration. Different concentrations not only change the apparent viscosity of the milk, but also the fluid type of the milk. At lower concentrations, milk exhibits plasticity (n > 1), at moderate concentrations (n ​​= 1), milk becomes a Newtonian fluid, but at higher concentrations, it becomes a non-Newtonian fluid, exhibiting a pseudoplastic fluid . feature (n < 1), that is, as the concentration increases, the value of n decreases gradually from large to large. Although temperature has an effect on the viscosity of milk, temperature has no effect on how the milk flows. Among all the influencing factors, the viscosity of yogurt is mainly due to the precipitation of protein in the presence of lactic acid. Thus, the protein content naturally thickens, and acidity is also a factor. So the lactic acid bacteria used (mainly with different acidity) has an influence on this. . Of course, the viscosity can also be enhanced by adding thickeners or including other excipients. So what factors will affect the viscosity of yogurt in the later stage?

1. Sterilization: The denaturation of whey protein in milk and the reaction with casein will start at a heating temperature of 90-95°C, which will reduce water precipitation and increase viscosity, thereby improving product quality.

2. Refrigeration: Freezing will cause some curd particles separated during processing to coagulate again into the network structure of curd particles, and the swelling of denatured whey protein will increase the water retention rate, so frozen yogurt can be made. Restore some viscosity.

3. Homogenization: Homogenization can make the particles (fat globules, milk protein, etc.) in raw milk smaller, promote the combination of tiny fat globules and casein micelles, and facilitate the increase of protein gel volume and the formation of proteins . Soft milky and curd texture: homogeneous raw milk has a higher viscosity than heterogeneous raw milk.

4. Conveying and filling: the number of tubes, the flow rate, the length and diameter of the pipeline, and the shear force of the filling pump and the can of the conveying pipeline will all affect the viscosity of the yogurt. In order to reduce the loss of yogurt viscosity, the oil pump should use a small power screw pump. The pipeline design should be as short as possible, the pipeline should be short, the pipeline should be large, the turbulence should be controlled during the production process, and the filling machine should be completed. It can be large to ensure the quality of the yogurt.