RESULTS

“THE WORK PERFORMED AND THE RESULTS ACHIEVED”

The major objectives assessed against milestones during the project have been successfully achieved by the project partners and now there is available a method for meat tenderization using HPUs effective for industrial primal beef cuts. Moreover, a standardized method for industrial meat quality grading based on “tenderness” was developed and a prediction software tool for the selection of the HPU best protocol and the prediction of the final tenderness achieved for each meat cut is available.

First, a guideline for easy grading of the initial quality (before being tenderized) of the most common beef meats in the European Market was performed, it allows to classify meat samples based on their initial tenderness degree before being tenderized. Meat quality is an expression which is used for describing the overall meat characteristics, including physical, chemical, morphological, microbiological, sensory, nutritive and culinary properties. The appearance of meat, its texture, juiciness, tenderness, smell and taste are some of the most important characteristics of meat from the consumers’ perspective and they influence their buying decision. The tenderness of beef is the attribute most demanded by consumers and its improvement is the primary reason for post-mortem aging. Meat aging is a process involving post-mortem proteolysis of myofibrillar proteins in muscles. Tenderization begins shortly after slaughter and increases after the rigor mortis phase. To improve the consistency of meat quality with respect to tenderness, beef should be aged. It has been shown that during the aging process certain changes take place in portions of the structure of collagen and muscle fibers. Currently, it is thought that enzymatic-caused changes in the structure of muscle fibers are largely responsible for the increase in tenderness. The most widely used instrumental test for meat tenderness evaluation is Warner-Bratzler shear force (WBSF) test. However, numerous factors can affect the results of Warner-Bratzler shear force measurements. The one with perhaps the largest potential impact is the orientation of the cores relative to the muscle fibers.  Sensory analysis is generally considered as the reference method to evaluate eating quality. For these reasons also sensory evaluation has been reported in several studies to predict tenderness. Sensory properties of meat which are agreeable to the senses make contributions to meat palatability. Important sensory characteristics are texture (hardness), juiciness and chewiness. Sensory evaluation of texture is made by means of attributes, which can be established, well a priori by the sensory analyst, well a posteriori, after consensus has been reached between the assessors.

Two model have been performed, one based on instrumental measures (WBSF) and the other on sensorial (hardness).  To perform the two models, firstly there were analyzed correlations between the selected parameter (WBSF or hardness score) and different parameters to select the main factors contributing to meat tenderization, secondly there were fitted both regression models  to predict beef meat tenderness finally it was developed the guidelines for easy grading of beef meat quality available for beef producers. To achieve this goal, a scale that takes values from 0 to 10 is used.

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To use these models it should be known a series of data about beef meat and its origin:
•    Gender
•    Age of the animal
•    Day after slaughter
•    Type of cut

Once this information is known, there must be assigned numerical values depending on selected variables as described below:
•    GENDER:
o    1- Female
o    2- Male
•    AGE  OF THE ANIMAL
o    The number of years
•    DAY AFTER SLAUGHTER
o    the number of days that have elapsed since the slaughter
•    TYPE OF CUT:
o    1-Blade
o    2-Toploin
o    3-Sirloin
o    4-Rump
o    5-topside
o    6-outside

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Once values have been assigned, it is possible to calculate the meat hardness/tenderness by defined mathematical multiple regression formulation.

After the completion of a full characterization of the selected meat samples, a software prediction tool was developed in MATLAB programming language. The tenderness prediction software uses a simple user interface and will have a dual functionality:
-To help to define the most suitable tenderization protocol for each meat sample: selection of time, intensity of the HPU process as a function of different initial meat parameters (age of the animal, breed, sex, size and meat cutting area).
-To predict and quantify these values for a final tenderness achieved (in a 0-10 numerical scale) after the HPU treatment for each meat cut.

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It is extremely user-friendly tool: there are three main sections, the inputs block, the outputs block and the last section dedicated to instruction, credits and reset button. The inputs section allows the user to select the meat type, the Tenderization level desired and the proportional coefficient between electrical and acoustic power. Once selected the input values, the user pushes the button “calculate” and immediately the software shows the estimated values for the time of treatment (min), acoustic power (W) and Energy consumption.  An “Instructions” button shows a list of instructions, consisting of four simple steps.

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A credits box gives further information about the project.

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This will be an effective industrial method for meat quality grading based on tenderness as the most important quality determinant. Moreover the software tool is fully opened to further implementations.

Finally, the results of the ULTRATENDER project show that a suitable high power ultrasound treatment can be used to increase the tenderness of beef meat cuts. However, the validation of the high power ultrasound treatment of beef meat with respect to its effect on tenderness demonstrated that such a tenderization is not possible for all cuts of all animals (female/male and age). Significant quality improvements are obtained especially for the outside cut from steer and the sirloin from heifer. These positive changes are detectable both by instrumental analytics (shear force) and by sensory tests. The effect of HPU treatment was evaluated by detection of pH-values, L*, a*, b* colour measurement, cook loss and Warner Bratzler shear force analysis. HPU treatment had no impact on the quality parameters pH-value, colour, cook loss and microbial status. No significant differences were observed in compositional parameters between HPU treated samples and control samples. No loss or detrimental change of the meat quality was observed.  The product texture was evaluated with the Warner-Bratzler shear force test. There was a significant effect of HPU treatment with the maximum power on peak shear force (p<0.05) for heifer blade, sirloin and outside. After HPU treatment the peak shear force was significantly reduced. Also a significant effect of HPU treatment on peak shear force for steer outside cut was observed. The shear force was reduced. HPU treatment also showed a tendency to reduce the peak shear force of ox rump cuts after longer treatment times. The ULTRATENDER results also show that a further increase in energy input and treatment intensity may be required to enhance the treatment effect. In this context, the mathematical model developed helped to define the most suitable HPU and geometrical parameters for the meat tenderization process. 


Multiple FEM simulations allowed to design the experimental set-up and investigate the main parameters involved. Acoustic simulations` results allowed to define the geometrical parameters and the correct positioning of the meat samples in the US bath. In addition, thermal simulations’ results allowed to prevent an excessive temperature increase in the meat.

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Based on that, an industrially applicable prototype to test the high power ultrasound treatment and evaluate the effects on beef meat quality is now available as one result of the ULTRATENDER project.

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The treatment tank of the prototype can only be used in connection with the power generator. The generator transmits the power to the transducers in the side walls of the treatment tank. The meat pieces to be treated are placed in the holding basket. The basket is connected to the lid through a fixed guide rail. Raising and lowering of the basket can be realized by the up and down button of the lid. At the end of the treatment time the product basket is transported upward together with the basket. After reaching the end position by the lid, the basket is disconnected from the lid and the product can be withdrawn from the basket.