Viscosity Evaluation of Yoghurt

Texture Analyzer

Evaluation of Food Products

Yoghurt is typically eaten in a semi-solid state using a spoon. In recent years, however, demand has increased for lower viscosity yoghurt beverages that customers can drink using a straw. Since texture and sensation when swallowing are extremely important characteristics of yoghurt, texture evaluations for viscosity and hardness are indispensable. The EZ Test texture analyzer can be used for this sort of evaluation.

  • Jig: (1) Tubing test jig (2) Jig platform
  • Test conditions: 90 mm/min
Sample
Max. Test
Force (N)
Average Test
Force (N)
10 mm to 30 mm 
Yoghurt A 6.9 5.9
Yoghurt B 6.2 5.0

In this example, two types of yoghurt were extruded through a disk with a hole diameter of 5 mm. The average test force was calculated between 10 mm and 30 mm strokes. The results show that Yoghurt A is harder and more viscous, as its average test force was higher.
These testing jigs can be used as an index to evaluate the viscosity of samples.

Tubing Test Jig

The sample is placed in the sample container, and compressed by the extrusion compression plate. There is a hole in the bottom of the container, and the test force is measured when the sample is extruded through the hole in the disk. The disk hole size can be changed depending on the sample viscosity and the presence or absence of content.

Texture Analyzer

EZ Test

This destructive testing machine is used for the tensile, compressive, and bending testing of specimens. It conducts quantitative strength measurements on specimens by measuring the applied test force and the stroke to determine the specimen deformation. A wide range of jigs is available for the strength testing of packaging materials and for the numerical evaluation of food-texture characteristics such as consistency, texture, and mouth feel.