A consumer’s perception of meat is mainly based on its consistency, slicing properties, chewiness, juiciness, springiness and firmness. These factors can have a huge impact on the consumer’s decision to repurchase the product. Hence, quality control of meat products is given the utmost importance in the meat manufacturing process. Texture analysis is done in whole tissue and processed meats to assess ideal combinations of ingredients, evaluate the impact of processing methods and highlight quality inconsistencies.
The quality of meat greatly depends on its texture, which is the result of the way animals are reared and the way the meat is processed. The texture of the meat can vary due to the highly complex structure of meat muscle tissue and the various processes the raw meat undergo such as slaughter methods, storage time, storage temperature, salting and smoking. It can also be affected by cooking time and temperature. Heat can cause a number of chemical changes associated with the meat muscle fibres and connective tissues and it can also change its water holding capacity. This will produce a much drier meat texture that is less juicy and tender.
To assess the quality of meat, a universal texture testing equipment can be used. These equipment test the meat texture by measuring the applied resistance of the meat to a force acting on it. Based on the texture profile analytics, the operating conditions can be controlled or improved with respect to the current texture profile of the meat.
How Meat Texture is Analysed?
During texture analysis of meat, the biting action of the meat in the mouth is simulated. A meat sample is placed on the analyser test bench and the arm of the texture analyzer contains the load cell, to which a probe or fixture is attached. Depending on the type of meat sample to test, an appropriate probe/fixture is selected to deform, penetrate or cut the meat sample. The test is conducted as two-cycle compression, using probes that apply force on the meat sample.
Meat Texture analysis is generally performed using two main techniques: Warner-Bratzler test, rapid Slice Shear Force Test and Kramer shear cell. These tests include jigs and fixtures to shear through a meat sample and blades to imitate the slicing action on meat. The fixtures and blades can be attached to the universal testing equipment to perform specific testing.
Let’s discuss these testing techniques in further detail.
Warner Bratzler shear Test
The Warner-Bratzler shear test uses shear blades to cut through the meat simulating the cutting of meat in
the mouth during the first bite. It is done to measure the force required to cut the meat sample. This test set consists of a rigid frame supporting a shear bar. The frame fits Interchangeable shear blades which are available in different geometries.
The jig in the Warner-Bratzler set can be used for slicing or shearing tests on meat products and vegetables too. For meat testing, a triangular slotted blade is used. Cooked steaks are first cooled and then six core samples parallel to the longitudinal orientation of the muscle fibers having 12.7 mm diameter each are taken for the test. The sample is positioned such that the cut is perpendicular to the muscle fibres this way shorting the muscle fibres and making the meat more malleable. The force to shear each core sample using the slotted blade in compression mode is then measured. In this process, the resistance of the meat to shearing is recorded.
However, this testing technique has some limitations. The width of the slices and length of the muscle fibers for each cut need to be consistent. Also, the angle between the probe and muscle fibers should be set at about 90 degrees. This makes it difficult to test meat samples with different geometries.
Rapid Slice Shear Force Test
The Rapid Slice Shear Force Test can be used as an alternative to the Warner-Bratzler test for shearing tests in meat products. The test set includes a custom-designed flat, blunt-ended blade. Unlike the Warner-Bratzler test, this method only requires one measurement on a single 50 mm by 10 mm meat sample cut orthogonal to muscle fiber orientation immediately after cooking. Slice shear force test is therefore much quicker than the Warner-Bratzler shear force test because the meat sample does not need to be cooled before testing and only one slice is enough for testing. The measurement can be completed in less than 10 minutes using the Rapid Slice Shear Force Test, which has significant benefits in commercial applications. In addition, getting one good slice is easier than getting six good core samples with uniform diameters.
Kramer shear cell Test
The kramer shear cell test can be used to test the firmness of canned and reformed meat. The test includes multiple blades which allows for samples of variable geometry to be sheared. The fixture included in the test set incorporates the textural methods of compression, shearing and extrusion through slots in the base of the cell.
The test begins with weighing the cut cubes of the meat sample and then placing them into the cell ensuring a level surface. At the beginning of the test, the blades approach the meat surfaces at a pre-test speed of 2 mm/s. When a trigger force of 10 g is detected at the sample surface, the blades proceed to compress, shear and penetrate through the sample over a target distance of 35 mm at a test speed of 2 mm/s. The measure of hardness/firmness evaluated from the software correlates with the amount of force required by the teeth to compress and cut into the sample. The higher the amount of force, the firmer the sample.
General Texture Measurements
The universal texture analyser can be equipped with a variety of test jigs to make a wide range of texture measurements on meat samples. For instance, the Volodkevich bite test consists of a stainless steel probe shaped like an incisor that provides results that correlate well with meat toughness. It comprises upper and lower jaws that are fitted to the load cell and the test platform. The meat sample is positioned in the lower jaw and the biting action is enabled by the compressive movement of the upper jaw shearing into the test sample.
For analysing the consistency in burger patties, a cylindrical probe which opens out in an inverted cone shape with a flat end of 25 mm diameter is used to apply force to the patties. The test basically simulates the biting action in the mouth by replicating the effects of two bites of the burger patty sample. With the help of software, the force, distance and time during the entire simulation process can be monitored, which is then used to calculate texture critical parameters such as adhesion force, chewiness, hardness, springiness, resilience and other factors.
The above tests are generally carried out throughout the supply chain process of meat production, aiming to enhance the eating quality of chicken, beef, lamb and pork. It is speculated that the improvements in the objective measurements of carcass and meat quality will result in the betterment of farm practices.
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