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

Tuesday, 16 August 2016

Noodle quality testing: a range of texture analysis methods for a wide variety of noodle types – Part 2

ASSESSMENT OF UNCOOKED PRODUCT QUALITY

Breaking strength gives a measure of the strength of the dry noodle block/cake. This determines how well the product tolerates shipping and may indicate how well a product holds together upon cooking.

Processing conditions can have a huge effect on breaking strength quality. Breaking strength has seldom been used to date in published literature to predict the cooking quality of noodles, but it may be useful as a QA procedure for the noodle industry, as the measurement can be done more rapidly than a cook test, and it can be used as a near-line procedure.


Breaking Strength of Dry Noodle Blocks/Cakes

Suitable for: Any uncooked cake/bar that is consistent in dimensions or single noodle strands

Breaking strength/stress of dry noodles can be determined by performing a Three Point Bend test (as shown below). This fixture supports the noodle sample across a span of known distance. A force is applied to the centre of the sample (which is also central to the supports) and the breaking stress is determined. Such a test may, for example, be used to assess the effect of different ingredients used or to examine typical finished product problems such as moisture uptake or how the product will survive during packaging and transit.


Three point bend testing of dry noodle bars
The breaking strength (force per unit width) or breaking stress (force per unit area) of the sample is taken as the maximum strength or stress value of the curve. Other textural characteristics that may be of interest are the distance to first break, the area under the curve during application of force and the linear distance. The distance to break gives an indication of the brittleness of the sample as this shows how far a sample can be deformed before fracture. The area under the curve indicates sample toughness; the higher the area value, the more energy is required to test the sample. The linear distance is an indication of crispness; the longer the total length of the curve line, the more brittle/crispy is the sample.  

Flexure testing of Single Dry Noodles

Suitable for: Single, long, uncooked noodle strands, for example: Kuk Soo, Harusame, Hiyamugi, Naeng Myun, Straight Rice Vermicelli, Shanghai Noodles, Soba, Somen, Udon


Drying is the most critical, as well as the most difficult step in noodle production. If noodles are dried too quickly, moisture gradients are created that crack, or check, the noodles. This is considered to be driven by the difference between environmental relative humidity (ERH) and noodle RH. Checking can occur during the drying cycle, but it can also occur up to several weeks after the noodles leave the drier. This means that the product can check after it is packaged and sold and subsequently creates a negative customer response. A test for this would therefore be a useful monitoring procedure.


Spaghetti/Noodle Flexure Rig
A fixture which can be used to examine strands of noodle for potential checking is the Spaghetti/Noodle Flexure Rig (left). Lengths of dry noodle are trimmed to a known length and positioned between upper and lower supports in centrally located holes. The upper support is connected to the load cell of the Texture Analyser and the lower support to the base of the Texture Analyser.

A compression test is performed during which attention is paid to fluctuating force before the final break which would indicate weaknesses within the sample, e.g. checking. Also shown is a typical curve obtained from such a test.

Extensibility Measurement of Uncooked Noodle Sheet



Suitable for: Uncooked Noodle Sheet, Wonton Sheet or Rice Paper
 

The Noodle/Pasta Loop Tensile Rig (below left) provides such a solution and aids manufacturers in testing the resilience and consumer appeal of noodle sheets. This Community Registered Design is an important advancement in gauging product quality and maximising repeat purchase.

Guidelines for noodle cooking times are typically trialled extensively to ensure that consumers can produce ideal results at home. In an age of increasing culinary sophistication and a more discerning consumer, finding a precise solution for creating the preferred noodle texture is of paramount importance. 


The Noodle/Pasta Loop Tensile Rig allows manufacturers to perfect the formulation of their products with the aid of repeatable, scientific analysis. This, in turn, leads to enhanced customer satisfaction.

The Noodle/Pasta Loop Tensile Rig measures the force required to stretch cooked/uncooked pasta or noodle samples to breaking point, providing an accurate measure of their extensibility. Previous clamping methods have encountered difficulties due to unequal pressure and failing at the sample mounting points. It is important that the product breaks within the gauge length in order to guarantee accurate test data. For this reason, the new rig comprises a unique annular sample cutter, producing a sample shape from the uncooked sheet that impedes breakage at the holding points. 


Prior to testing, samples are mounted to a separating rod fixture on washers that are specifically designed to prevent the noodles from breaking at the point of attachment. Vertical movement of the upper rod is applied until the noodle breaks, while Exponent software records the force required to do so.

Controlled testing not only provides unambiguous quality assessment standards but can also indicate how a product may react to further processing during manufacture.




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.

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Watch our video about testing of pasta productsDownload a published article covering methods for the testing of pasta products

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