When using a knife to cut through a sample the effort required to push the blade downwards gives an indication of the FIRMNESS/HARDNESS/TOUGHNESS of a product. It makes sense, therefore, that when measuring CUTTING FORCE, one would choose a knife/blade as the tool for the measurement of that property.
Depending upon the product being cut will depend upon the terminology used to express the property being experienced. A sample requiring a higher amount of effort to cut may be termed ‘tougher’. Hardness/firmness are synonymous but depending upon the product type may be a property that is more commonly referred to.
Look at Hardness as the effort you use to push your shopping trolley round the supermarket. The difficulty of pushing it is dependent on the shopping being added. The more shopping you put in, the harder it is to push, i.e. the greater force you have to apply. The toughness or work is the accumulated effort of the whole journey around the supermarket from empty trolley to the checkout!
The toughness 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 sample to test.
The descriptions Tenderness and Toughness are not absolute. They have to be defined by agreement between the parties using them. Tenderness maybe the inverse of toughness, as perhaps softness is the inverse of hardness.
Typical properties that can be obtained from a texture analyser graph:
Work of Shear, Toughness, Chewiness, 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 toughness/ cutting force 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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