Tofu texture

In the Far East, tofu is the most popular soybean food whilst in the West, tofu is gaining in popularity.

Tofu is very similar to cheese in appearance, texture, and chemical composition. By controlling the amount of coagulants and pressure applied during moulding, the texture of the tofu may be varied from extra firm, firm, soft, to silken.

The quality of tofu depends mainly on quality of raw beans. Its firmness and elasticity are its primary textural characteristics which can be measured easily via a small deformation penetration test using a Spherical Probe (as for the testing of cheese) or via a compression test using a Cylinder Probe larger than the surface area of the test sample. This is able to provide a small deformation test, whereby the ability to recover (elasticity of the sample) is measured.

 Typical ways to assess firmness and springiness
of elastic solids on a Texture Analyser

 
A guillotine or Knife Blade can also be used to cut/shear the sample. In work carried out at Stable Micro Systems, the tofu was removed from the place of storage just prior to testing and its' packaging then cut into 2 sample strips, each with a 40mm width. A sample strip was positioned perpendicular to the blade and 3 tests performed onto it (towards each end and a central one, ensuring that they were equidistant and not too close to each other or the edges).

Using a Guillotine or Knife Blade to cut/shear tofu sample

The curves below were produced from shearing four different kinds of tofu tested at room temperature straight after removal from the refrigerator at 5°C.

Test results obtained from a dozen samples (of each kind) give the following typical mean maximum force values:

 
Due to the wide surface of the sample in comparison to the small probe size (if using a small cylinder or ball to test the sample firmness), a number of tests can be performed onto the same sample surface, providing they are done with enough distance apart and not too close to the edges.

Small cylinder probe on Texture Analyser

The curves below were produced from testing two variations of firm tofu, one smoked and one unsmoked using a 6mm cylinder probe.

Test results obtained from the two samples give the following typical mean values:

Whether cutting, penetrating or compressing tofu samples, homogeneity provides the benefit of more repeatable results which potentially allows easier sample comparison of different tofu varieties or production batches.

There is a Texture Analysis test for virtually any physical property. Contact Stable Micro Systems today to learn more about our full range of solutions.

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For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

The TA.XTplus texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

No-one understands texture analysis like we do!

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