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Test tools for texture analysis and viscosity testing

Puncture needle for texture analysis

  • Applications: The puncture test was first used in 1925 for characterization of gelatin substances.
    • Determination of the level of freshness of fruit and vegetables
    • Determination of the level of freshness of baked products
  • Specimen material: Fruit, vegetables, baked products
  • Function description: The puncture needle is used for puncture tests to determine the freshness of various foodstuffs.

    It is pressed into the specimen to a defined penetration depth. A significant force reduction is visible as soon as penetration occurs.

Back extrusion fixture

  • Application:
  • Specimen material:
  • Function description:

    The test substance is loaded into the cell. The piston travels downwards in the cell, thereby forcing the material upwards through the annular gap. When the piston is raised, the material flows back through the annular gap into the cell.

  • Advantages:
    • The test cycle can be repeated as often as required, with freely selectable shear rates. The test can be optimally adapted to the test material, and the viscosity can be measured across the entire shear range with one single test.
    • The viscosity can be determined directly in containers from ongoing production. This rules out prestressing of the material caused by transfilling.
    • Flow influences that occur in production plants can be reproduced by altering the annular gap and the moving speed.
    • Use of a larger annular gap allows fruit preparations to be tested also.
    • Automatic pre-conditioning of the material is also possible where required.
    • Adjustment aids allow the annular gap to be set quickly and easily.
    • An insert-plate with alignment pins ensures precise location of the back-extrusion cell following cleaning.
    • Test results on Newtonian fluids correlate with results from measurements with rotational viscometers. Obtain reproducible, comparable test results for non-Newtonian fluids, generally with more sensitive characteristics than those obtained with rotational viscometers.

Compression die

  • Applications: Testing the hardness, firmness or pressure-sensitivity of semi-solid products, for example for analysis of the stacking behavior or aging behavior
  • Specimen material: Butter, cheese, fruit, pasta, similar materials
  • Function description: The compression die is screwed on to the compression die holder. During the compression test the compression die penetrates into the specimen.
  • Advantages: Screw connection for fast, easy changes.

3-point flexure test kit

  • Applications: 

    • Determining the breaking strength of baked products, chocolate bars and muesli bars
    • Determining the level of freshness of vegetables
    • Tests to ISO 178 and ASTM D790 (plastics)
  • Specimen material: Baked products, chocolate bars and muesli bars, vegetables, plastics

Warner-Bratzler shear device

  • Applications:
    • Approximate simulation of the "bite behavior" (canine teeth) when eating fish, meat, pastries
    • Determination of the tenderness/toughness of meat and fish products
    • Determination of the shear behavior of pastries
  • Specimen material: Fish, meat, pastries
  • Function description: The Warner-Bratzler cutting device consists of a slotted blade guide, upon which a round or rectangular specimen can be placed, and a blade with blade holder. The base frame is used to mount the specimen. During the test it guides the blade.
  • Advantages: Good result reproducibility means test is used very frequently and serves as a kind of “standard”.

Kramer shear cell

  • Applications:
    • Approximate simulation of a one off bite of chopped foodstuffs
    • Determination of texture behavior of small pieces of fruit and vegetable products, cereals, etc.
  • Specimen material: Fruit, vegetables, cereals, similar materials
  • Function description: The Kramer shear cell simulates biting of chopped foodstuffs.

    It consists of an upper and a lower slotted cell, in which the specimen material lies, as well as a blade unit with rectangular blades. The blades drive through the inserted specimen material at a constant speed, compressing and shearing it until it is pressed through the cell's floor. As a result you obtain the force displacement or force time sequence, from which you can tell how the specimen reacts to chewing motions. The extruded specimen material is collected on a universal work platform.

  • Advantages: The blades enable simultaneous measurement at multiple locations rather than just a single location, evening out local texture variations.

Ottawa cell (OTMS cell)

  • Applications:
    • Determination of the firmness/tenderness of vegetables
    • Determination of the hardness/crispness of muesli, cornflakes
  • Specimen material: Vegetables, muesli, cornflakes, similar materials
  • Function description: The Ottawa cell (OMTS cell) is used to approximately simulate chewing behavior. It does so by compressing and extruding the foodstuff specimen. The cell has an open floor into which various extrusion plates can be inserted.

    The round or rectangular plunger moves downwards at a constant speed, compresses the specimen and forces it through the extrusion plate. The result obtained is the force/time or force/displacement curve. Parameters such as crispness, hardness/firmness, degree of ripeness or extrusion energy can be determined from the type of curve.

  • Advantages:
    • Various extrusion plates or a sealing plate available for the cell.
    • Plungers with suitable reduction inserts available for different volumes.

Dough tensile test fixture

  • Applications:
    • Tensile tests on doughs and gluten (protein binders) to determine dough properties (e.g. elasticity, force at break of dough-strips) and ensuring optimum, consistent dough formulations.
    • Determination of the elastic properties of chewing-gum.
  • Specimen material: Dough, gluten, chewing-gum
  • Function description: The dough tensile test kit consists of a specimen preparation unit and the test fixture. Paper strips are inserted into the specimen preparation unit. Dough is poured in and pressed into the grooves.

    After a specified rest period, one strip of dough with paper is placed on the test table. The paper is pulled off and the specimen is inserted into the test fixture. The dough-hook pulls on the dough from below.

  • Advantages: A plastic cover can be placed over the dough-hook to prevent breakages.

Butter cutter

  • Applications: Determining the hardness and cuttability of butter and similar cuttable foodstuffs
  • Specimen material: Butter, cheese, eggs, vegetables, fruit
  • Function description: The butter-cutter is used to determine the hardness and cuttability of butter and similar foodstuffs. The butter is placed on the universal specimen platform. The wire slices through the butter and the force required is recorded. Information on properties of the butter such as hardness and spreadability can be obtained from the force-displacement curve.

    The test is highly temperature-dependent and should be performed at defined temperatures.

Lid peel test kit for peelable packagings

  • Applications: Testing the sealed seams of peel-off packaging Peeling off the cover or sealing material of dimensionally stable or rigid packaging (peel test)
  • Specimen material: Cover or sealing material
  • Function description: The peel-test kit is used to pull off the cover or sealing material of dimensionally stable or rigid packaging. The packaging tracks automatically by means of a sliding carriage. The peel point is always located in the test axis, ensuring a constant peel angle of 90°. This guarantees uniform, reproducible force measurement.

    The fixed clamp reduces deviations from the test axis which may arise due to the cover not being opened in a smooth motion.

  • Advantages:
    • The device can be used to test packaging in a wide range of shapes and heights. The vertically adjustable holding-down clamp can very quickly be adjusted to different heights. Use of the holding-down clamp enables a wide range of packaging shapes to be tested.
    • The test device can be adjusted quickly and easily to suit different packaging shapes, allowing tests to be performed on packaging taken directly from the production line.
    • Specimen support table and housing are made of brushed stainless steel.

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Interesting applications for testing of food

Test Fixtures for Texture Analysis

ZwickRoell offers a comprehensive selection ranging from standard test fixtures to customized solutions for texture analysis.
to Test Fixtures for Texture Analysis

Test Fixtures for Viscosity Measurement

The back extrusion fixture as an alternative to rotational viscometers—displacement of the test material via an annular gap between the piston and the cell.
to Test Fixtures for Viscosity Measurement

Food & Packaging

Whether you want to test the firmness of a sausage or cheese, the consistency of yogurt, mustard, or tomato paste, or the ease with which a sealing cap can be closed, ZwickRoell has a vast selection of test fixtures, which can also be customized to meet your unique testing needs.
to Food & Packaging

Downloads

Name Type Size Download
  • Product information: Kramer shear cell PDF 402 KB
  • Product information: Back extrusion fixture PDF 485 KB
  • Product information: Warner-Bratzler shear device PDF 281 KB
  • Product information: Puncture needle for texture analysis PDF 277 KB
  • Product information: Compression die PDF 148 KB
  • Product information: Ottawa cell (OTMS cell) PDF 5 MB
  • Product information: Dough tensile test fixture PDF 374 KB
  • Product information: Butter cutter PDF 142 KB
  • Product information: Lid peel test kit for peelable packaging PDF 98 KB
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