When you BITE into something you perceive how hard or firm something is. Whilst Hardness/Firmness is commonly the textural property possessed by most products, the words BITE, TOUGHNESS or CHEWINESS may often be substituted for a textural property more associated with a food product. Toughness (or 'chewiness') is commonly the textural property possessed by meat, fish and poultry products but can also be the term that is used for baked products such as tortillas, pancakes or pizzas.
If one considers that if the top front teeth were pulled from a curve-shape into a straight line they would represent a 'knife edge'. Using a knife blade (or series of knife blades together) gives a close representation of the biting or cutting action and therefore the measurement of these related parameters.
The toughness/chewiness parameter is often taken as the total positive area under the curve. This measurement effectively records the total 'work' involved in performing this test. It therefore follows that a higher area value indicates a higher amount of energy involved in performing the test and subsequently is translated as a tougher/chewier sample to test.
Typical properties that can be obtained from a texture analyser graph:
Work of Shear, Toughness, Biting Force, Cutting Force, Hardness, Firmness
Typical Texture Analyser graph with annotated properties of sausage shearing test
Typical Probe/Fixture used for Measurement:
Stable Micro Systems’ range of blades vary considerably in size, material, thickness and sharpness. In general they measure the Bite/Cutting Force of products which in some instances can relate to their 'Toughness'. When a product is uniform (homogenous), a single blade test may be adequate for the repeatable assessment of the product.
However, quite often, a product is non-uniform (heterogeneous) in make-up. For example, cereal bars are of different structure throughout their length. A single cutting test may encounter a peanut, toffee piece and hard wheat piece. The same cutting test done further down the length of the product will produce a different result; this time the blade may encounter a fruit piece and a chocolate chip. The same type of explanation can be given for a piece of meat.
To assess these types of product in a more reproducible way, the recommendation is to perform a multiple shearing test (most often using a Kramer Shear Cell). This test performs 5 or 10 cutting tests within one test and therefore creates an averaging effect.
The above are only typical examples of biting force/ chewiness measurement. We can, of course, design and manufacture probes or fixtures that are bespoke to your sample and its specific measurement.
Once your measurement is performed, our expertise in its graphical interpretation is unparalleled – no-one understands texture analysis like we do. Not only can we develop the most suitable and accurate method for the testing of your sample, but we can prepare analysis procedures that obtain the desired parameters from your curve and drop them into a spreadsheet or report designed around your requirements.
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