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

Tuesday, 19 August 2014

Maximising meat texture – 3 popular ways to test meat

Meat texture is fundamental to consumer satisfaction

Convenience is a key driver in the purchasing decision of today’s consumers. As they become increasingly time-poor, there is a surge in demand for easy-to-prepare foods. 

This is reflected in the success of the ready meals market which has flourished throughout Europe, even in countries where the home-cooked family meal has long been traditional. Benefitting, in particular, from the growth of the ready meals sector is the meat industry. 

In their quest for convenience, consumers are disinclined to compromise on food quality, which leaves manufacturers with the difficult task of balancing the two. Products must be reminiscent of ‘home cooking’, while being quick and easy to prepare. Although taste is a big concern, a product’s texture and mouthfeel is equally important to the consumer’s overall enjoyment. Undesirable texture can significantly reduce the appeal of ready meal foods, resulting in poor sales.

The problem with processing

Meat is a highly desirable ingredient for ready meals and frozen foods. Due to its delicate nature and relatively short shelf life, the preparation of meat for convenient foods can be complex, entailing various processes to ensure good stability and food safety. These procedures can have an adverse effect on meat ingredients and often result in a tough, dry texture and bland taste.

Analysing the texture of meat products provides an effective way to monitor these changes. Various tests can be carried out on chilled, frozen, reformed, pre-cooked or breaded meat to gauge the quality of its mouthfeel. With the help of sophisticated texture analysis instrumentation, manufacturers can evaluate the effects of processing methods and times, highlight quality inconsistencies and adjust formulations or techniques accordingly.

Manufacturing processes and treatments used to achieve meat tenderness and the desired sensory characteristics often directly affect the muscle fibres. Tests that measure aspects of fibre characteristics are therefore central to achieving simple, yet accurate, ways to evaluate meat quality. A consumer’s first assessment and perception of meat texture occurs when biting through its fibres, so a logical test approach is to measure the force required to cut the fibres. This provides an indication of the consumer’s perception and identification of undesirable textural characteristics, such as toughness.

What’s the testing solution?

Shear genius
An effective method for analysing biting or shearing of meat and meat products is the Warner-Bratzler shear blade. Developed by Stable Micro Systems for use in conjunction with the TA.XTplus texture analyser, this technique is one of the most widely used devices for determining the textural properties of raw or cooked meat in food research and quality control procedures.

Warner-Bratzler blade - test in progress
Kramer Shear Cell - test in progressCharacteristic of the Warner-Bratzler shear is its V-shaped cutting blade, which helps to position the meat while testing takes place. Samples are placed on a platform beneath the Warner-Bratzler blade in a central position to its triangular inset and between a blade guide. The arm of the TA.XTplus then brings the blade down at a constant speed to perform a shearing test which determines the textural quality of the product. The higher the force required to cut through the fibres, the more difficulty a consumer would experience in biting the meat, therefore indicating its toughness.

For manufacturers wanting to accurately analyse samples that are variable in configuration or structure, the Kramer Shear Cell can be employed on the TA.XTplus. Testing with a multi-bladed device, results show an average of the forces required to cut through a sample of variable geometry. The instrument particularly lends itself to reformed meat pieces for ready meals, for example, fillet strips or chunks, and shaped poultry, such as chicken nuggets.

Reformed poultry products are often coated in a number of layers to provide flavour and texture as well as to add value. Prior to this, the meat must be formed correctly to produce an attractive shape and provide adhesion for the coating. Overuse of cryogens during the forming process can damage meat definition and result in textural deficiencies. Other factors, such as the cooking method, duration of cooking and meat choice, extend the range of potential difficulties. Using the Kramer shear cell, manufacturers can assess the overall textural quality of their products, highlight inadequacies and make appropriate changes to ingredients or processing methods.

MORS blade - test in progress
New Advances in Poultry Tenderness Measurement
Of the existing instrumental methods for measuring meat tenderness, the Meullenet-Owens Razor Shear (MORS) is the most recently introduced from research carried out at the University of Arkansas and has been established as a reliable predictor of poultry tenderness. The method has gained in popularity because of its high reliability as well as simplicity compared with that of other industry standards, the Warner-Bratzler (WB) shear or Allo-Kramer (AK) shear.  

The method uses a razor blade of defined dimensions attached to a TA.XTplus Texture Analyser which then performs a cutting/shearing test. Tests are performed on intact fillets using the MORS blade penetrating to a depth of 20mm providing a far less destructive method as only a small incision is made in the sample.

When performing cutting/shearing tests the consistent sharpness of the blade is always a consideration or cause for concern. The benefit of performing tests using a readily available craft knife blade (such as that shown) is that the blade can be removed and replaced after each test or an agreed number of tests, assuring edge sharpness and therefore increasing the repeatability of the results.

It is recommended that the sharp blade is replaced every 100 measurements for optimum shearing performance and hence result repeatability.

The MORS is not only as reliable as the industry standards and claims to exhibit a higher correlation to sensory attributes than the Allo-Kramer shear method, but also more rapid because of the elimination of the sample cutting steps. It has been reported that both the WB and AK shear are significantly affected by sample dimensions. Furthermore, the AK shear is so dependent on sample dimensions that it is a standard practice to divide the AK maximum shear force by the sample weight. 

The razor blade test has proven to also be less time consuming, as 60 measurements can be performed in 1 hour compared with 30 measurements in the same amount of time for the Allo-Kramer shear test. Measured forces are also substantially lower than those produced with a Kramer shear test, thereby allowing testing on a TA.XTplus Texture Analyser.

Tests using the MORS blade are conducted on whole intact fillets which minimises the experimental errors attributable to sample preparations, shortens sample preparation time and leads to a simpler testing solution. The application of the MORS method will thereby provide advantages over existing industry standards for poultry breast meat tenderness and be of benefit to the poultry industry as it could significantly save labour, time and expertise to implement for routine quality control.  

Razor blade shear energy (N*mm) is calculated as the area under the force deformation curve from the beginning to the end of the test and maximum shear force (N) is also recorded during the test. Both parameters used as instrumental assessments of meat tenderness. Results show that the optimal number of replications of the MORS for a reliable estimate of tenderness to be four shears or greater per fillet in predetermined shearing locations.  

Ensure textural quality is consistent
With the growing emphasis on convenience, manufacturers are under pressure to provide tasty and easy-to-prepare foods. Achieving this combination, particularly with meat products, requires extensive processing, along with various additives to optimise taste and texture. Texture analysis provides product developers with an efficient way to measure and quantify the effects of these procedures on meat. Using a variety of specially designed attachments, food manufacturers and processors can ensure that the textural quality of their meat products is optimum, thereby ensuring consumer satisfaction.

Watch our video about testing of meat and meat products Download a published article on testing meat products  Meat and Fish Testing solutions

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