How to measure and analyse the texture of food, cosmetics, pharmaceuticals and adhesives.

Tuesday, 30 August 2016

Noodle quality testing: a range of texture analysis methods for a wide variety of noodle types – Part 4

TEXTURAL QUALITY OF COOKED NOODLES [2]

Cooked Noodle Firmness Determination – Noodles tested in bulk
 
Suitable for: All cooked noodle types, particularly those of irregular shape and dimensions (e.g.wavy, those that will not lie flat to be tested) and thin/fragile samples that are difficult to handle as separate strands, for example: Arrowroot Vermicelli, Cellophane , Chinese wheat noodles, Chuka Soba, Dang Myun,  E-fu, Instant Noodles, Miswa, Ramen, Rice Macaroni, Rice Noodles, Rice Vermicelli, Saimin, Shirataki, Taiwanese, Wonton 

 
Single blade tests generally do not work well for short goods or for those noodle types that are difficult to lie straight. In this situation a multiple shear test using many cutting blades, e.g. a Kramer Shear Cell, is in most cases more applicable for the testing of a non-uniform sample or one with variable geometry.


A multiple shear test also has the benefit of larger surface area for testing thereby testing a more representative sample size. Sample preparation is quicker and less tedious than strand alignment and the curve produced has an averaging effect. However using the Kramer Shear blade inside its cell requires careful alignment, requires greater force capacity (which may not be possible using a single column Texture Analyser) and cleaning of the cell between tests takes time.

Alternatively, the recommended multiple shear device is a Triple Ring Cutting System (below left), which is circular and may be more suited to testing within a circular vessel where sample size is smaller. This system consists of three concentric cutting rings mounted on a head which is magnetically attached to the arm of the texture analyser. The sample is contained in a 95mm diameter vessel so as to present a sample of controlled depth for testing.


Triple Ring Cutting System
The size of the sample (typically 60g) should be controlled for comparison purposes between different noodle samples. The vessel is located on a centralising platform on the base of the instrument which possesses concentric rings for easy central alignment of vessels and protection of the instrument from water spillage.  The cutting rings are calibrated to recognise the distance at the inside bottom of this vessel as 0mm. 

The sample is sheared ‘in bulk’ and the result is an average of the forces required to cut through the sample to a distance of 0.5mm above the container base. The maximum force and area under the curve are usually calculated and termed the ‘firmness’ and ‘work of shear’ – in both cases a larger value indicating a firmer sample which would be perceived by the consumer upon eating. Figure ? shows a  sample comparison for this type of test.

The magnetic coupling of the test head allows for quick removal and replacement between tests for cleaning. This magnetic quick removal system is the first of its kind in texture analysis and supports the need for test procedures that have efficiency in mind. The cutting rings on the device are also removable for easy cleaning once all tests are complete.

As usual, the sample should be prepared according to specific cooking instructions for the noodle type. In general this involves cooking the sample in boiling water for several minutes then rinsing in cold water and draining.

In the case of instant noodles the ability to test in the container in which the instant noodles are prepared is of benefit as it reduces handling of the sample. However, noodle pots (either plastic or cardboard) do not possess a rigid base once hot water is added. Testing samples against a flexible base presents a significant compromise to repeatability in results as the pot deformation presents an unknown and potentially changeable distance parameter to the test. A flat calibration surface is required for cutting close to the vessel base.


Recently ‘low calorie’ / ’low carbohydrate’ / ’gluten free’ noodles have entered the market. When formulating a product like this the target is to aim for a texture close to the original noodle texture as there is already a high textural expectation of this type of product. 


The graph (right) shows the comparison of one such newly formulated low calorie noodle type against its similar original noodle type. Force to cut the noodles is three times greater which will certainly be perceived by the consumer as a considerably firmer noodle to eat.




We can design and manufacture probes or fixtures for the TA.XTplus texture analyser that are bespoke to your sample and its specific measurement.

Once your measurement is performed, our expertise in its graphical interpretation is unparalleled. Not only can we develop the most suitable and accurate method for the testing of your sample, but we can also prepare analysis procedures that obtain the desired parameters from your curve and drop them into a spreadsheet or report designed around your requirements.

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

TA.XTplus texture analyser with bloom jar 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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