JP6917598B2 - Texture evaluation method - Google Patents

Description

The present invention relates to a method for evaluating the texture of a food having a fibrous structure such as meat.

Conventionally, as a method of analyzing the texture of food, a method of analyzing the physical characteristics of food using a testing machine such as a compression tester or a tensile tester is known (for example, Patent Documents 1 and 2). However, with the parameters detected by these general analysis methods, when analyzing the texture of foods having a fibrous structure such as meat, it is not possible to detect fine differences in texture, and the texture is evaluated. It was not suitable as a classification method.

Japanese Patent No. 5616216 Special Publication No. 62-34375

An object of the present invention is to provide a method for evaluating the texture of foods, particularly the texture of foods having a fibrous structure such as meat, by a simple method using a conventionally used analyzer.

The inventors have diligently examined a method for analyzing and evaluating the texture of foods having a fibrous structure such as meat and tissue protein, but the conventional method enables satisfactory evaluation and classification of fine texture. There wasn't. Therefore, as a result of diligent research, it was found that the fine texture can be evaluated and classified by evaluating the parameters of the physical properties at the initial stage of slowly pressing the food, which led to the present invention.

That is, using a uniaxial compression tester, a cylindrical plunger with a diameter of 3 to 8 mm is moved at a constant speed of 0.05 to 1.0 mm / s to press the food, and the elastic modulus and elastic limit are reached. This is a method for evaluating the texture of a food, which comprises analyzing the strain and evaluating the texture of the food with a two-axis graph with the elastic modulus and the elastic limit strain as axes.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for evaluating the texture of a food, particularly the texture of a food having a fibrous structure such as meat, by a simple method using a conventionally performed analyzer.

Graph showing an example of stress-strain curve Graph showing stress-strain curve of Experiment 1 Graph showing stress-strain curve of Experiment 2 Scatter plot showing the relationship between the elastic modulus of Example 1 and the elastic limit strain Scatter plot showing the relationship between the elastic modulus of Example 2 and the elastic limit strain A graph showing the stress-strain curve of a typical sample of each sample of Comparative Example 1.

Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following description.

1. 1. Preparation of analytical sample The food to be evaluated by the evaluation method according to the present invention is not particularly limited, but a food having a fibrous structure such as meat is preferable, and not only beef, pork and bird meat, but also seafood fish meat. And histological proteins produced by extruding soybean protein and the like. The portion to be measured from these foods or processed foods is cut and the analytical sample is prepared. The size of the analysis sample is preferably such that the contact surface of the plunger, which will be described later, is flat and the size is at least twice the diameter of the plunger. Further, the thickness of the analysis sample is preferably at least 2 mm or more because if it is too thin, the reaction force from the plate on which the analysis sample is placed will be measured when pressed.

2. Measurement of elastic modulus and elastic limit strain
The prepared analytical sample is analyzed using a uniaxial compression tester. The uniaxial compression tester is not particularly limited as long as it can be pressed from top to bottom at a constant speed. If the moving speed is too fast, the stress at the initial stage of pressing cannot be measured. Therefore, the moving speed may be 1.0 mm / s or less, preferably 0.5 mm / s or less. Further, if it is too late, it takes time for analysis, so it is preferably 0.05 mm / s or more, preferably 0.1 mm / s or more.

The material of the pressing jig called the plunger used for the analysis is not particularly limited, and may be made of metal or plastic. The portion of the plunger in contact with the food sample is preferably cylindrical, and the diameter is preferably 3 to 8 mm. If the diameter is too small, the food may be stabbed before being pressed, and if it is too large, the elastic modulus at the initial stage of pressing will be low, making it difficult to evaluate the texture of the food.

The stress against strain is measured under the above conditions using a uniaxial compression tester for the analysis sample. The measured data is plotted on a graph so that the Y-axis is the stress and the X-axis is the strain, and a stress-strain curve as shown in FIG. 1 is created.

Calculate the elastic modulus and elastic limit strain from the created stress-strain curve. As shown in FIG. 1, the calculation method is to draw an approximate straight line (L) on the stress-strain curve from the strain value (S) at the time of stress occurrence, and elastically calculate the slope (K) value of this approximate line (L). Let it be a rate. Further, the value obtained by subtracting the strain value (S) at the time of stress generation from the maximum strain value (M) on the approximate straight line (L) is defined as the elastic limit strain. Such an analysis may be easily and automatically calculated by using the analysis software attached to the uniaxial compression tester to be used. Further, the maximum stress value before the strain becomes large and the stress drops sharply is defined as the breaking strength (P), which is a general measurement item.

The present embodiment will be described in more detail below with reference to examples.

<Experiment 1> About the diameter of the plunger (Test Example 1)
Heat 15 mm thick beef (peach) in a steam oven so that the internal temperature (central part) reaches 65 ° C, cut the lean part without streaks and large fat in 20 mm square, and analyze sample (medium). And said.

A uniaxial constant velocity intrusion test was performed on the analysis sample (medium) using a uniaxial compression / tension rheometer (RE-33005C, Yamaden Co., Ltd.) with a moving speed of 0.5 mm / s and a maximum strain of 0.99. rice field. The load cell used had a rated capacity of 19.6 N, and the plunger used was a cylindrical type with a diameter of 1.5 mm. In addition, the analysis sample (medium) was measured so as to press along the muscle fiber direction. The measurement was performed every 0.02 seconds, and the stress and strain were measured.

(Test Example 2)
The analytical sample (medium) was measured according to the method of Test Example 1 except that the plunger diameter was 2 mm.

(Test Example 3)
The analytical sample (medium) was measured according to the method of Test Example 1 except that the plunger diameter was set to 3 mm.

(Test Example 4)
The analytical sample (medium) was measured according to the method of Test Example 1 except that the plunger diameter was 5 mm.

(Test Example 5)
The analytical sample (medium) was measured according to the method of Test Example 1 except that the plunger diameter was 8 mm.

The analysis data of the measured sample was analyzed by breaking strength analysis software (BAS3305, ver2.3), and a stress-strain curve (FIG. 2) was created. Since I want to see the analysis blur, I have shown all the analyzed plots. As shown in FIG. 2, the smaller the diameter, the higher the rise (slope) of the stress-strain curve, which is preferable in terms of analytical sensitivity. , It was judged to be unsuitable because the stress value varies and does not become linear. On the contrary, when the diameter of the plunger is 8 mm (Test Example 5), the rise (slope) of the stress-strain curve is lower than that of the plunger diameter of 3 mm or 5 mm (Test Examples 3 and 4). It was thought that the analysis sensitivity would be weaker with a plunger with a larger diameter. Therefore, it is considered that the diameter of the plunger is preferably 3 to 8 mm, more preferably 3 to 5 mm.

<Experiment 2> Movement speed (Test Example 6)
The measurement was performed according to the method of Test Example 3 except that the moving speed of the plunger was 0.05 mm / s and the measurement was performed every 0.2 seconds.

(Test Example 7)
The measurement was performed according to the method of Test Example 6 except that the moving speed of the plunger was 0.1 mm / s.

(Test Example 8)
The measurement was performed according to the method of Test Example 6 except that the moving speed of the plunger was 1.0 mm / s.

(Test Example 9)
The measurement was performed according to the method of Test Example 6 except that the moving speed of the plunger was 5.0 mm / s.

The analysis data of the measured sample and the data of Test Example 3 were analyzed by breaking strength analysis software (BAS3305, ver2.3), and a stress-strain curve (FIG. 3) was created. Due to the large number of plots, the graph plots the stress every 0.01 strain for clarity. As shown in FIG. 3, in Test Example 9 in which the moving speed is as fast as 5.0 mm / s, it can be seen that the plunger is stuck in the meat because the stress does not rise even if the strain becomes large. Even in Test Example 8 in which the moving speed is 1.0 mm / s, the rise is slightly slower than in the other Test Examples, so it is considered that the plunger is slightly stuck in the meat piece for measurement. In the test plot where the moving speed is slower than 1.0 mm / s, there is no slow rise, so it is considered that the plunger can measure firmly without sticking to the meat. However, at 0.05 mm / s, sample analysis takes time. Therefore, the moving speed of the plunger is preferably 0.05 to 1.0 mm / s, more preferably 0.1 to 0.5 mm / s.

<Experiment 3> Evaluation of meat texture (Example 1) Evaluation with a plunger diameter of 8 mm As an analysis sample, raw meat (rare) of beef (peach) with a thickness of 15 mm and an internal temperature (center part) in a steam oven. ) Was heated to reach 65 ° C (medium), a sample heated to reach 80 ° C internal temperature (central part) in a team oven (weldun), and internal temperature (central part) in a team oven. ) Was heated to reach 90 ° C. (Bary Weldan), and a lean portion without streaks or large fat was cut into 20 mm squares to prepare an analysis sample.

Each analytical sample was subjected to a uniaxial constant velocity intrusion test at a moving speed of 0.5 mm / s and a maximum strain of 0.99 using a uniaxial compression / tension rheometer (RE-33005C, Yamaden Co., Ltd.). The load cell had a rated capacity of 19.6 N, and the plunger had a cylindrical shape and a diameter of 8 mm. In addition, the analytical sample was measured so as to press along the muscle fiber direction. The measurement was performed every 0.2 seconds, and the stress and strain were measured. Eight specimens were analyzed for each sample, and the average value was used as the sample value.

The analysis data of the measured samples were analyzed by breaking strength analysis software (BAS3305, ver2.3), and the elastic modulus and elastic limit strain of each sample were measured. The elastic modulus and elastic limit strain value of each sample are shown in Table 1 below.

FIG. 4 is a scatter plot in which the values of each sample are plotted with the elastic modulus on the X-axis and the elastic limit strain on the Y-axis for the measured values of the plunger with a diameter of 8 mm shown in Table 1, and the meat is heated. By doing so, it is possible to evaluate the texture of the meat by evaluating the value of the elastic limit strain together with the elastic modulus although it does not change. In the case of beef thigh meat, the difference is small, but if the meat quality is a little softer, it is possible to evaluate the difference in texture of finer meat.

(Example 2) Evaluation with a plunger diameter of 3 mm Each sample was analyzed in the same manner as in Example 1 except that the plunger diameter was 3 mm, and the elastic modulus and elastic limit strain of each sample were measured. The elastic modulus and elastic limit strain value of each sample are shown in Table 2 below.

FIG. 5 is a scatter plot in which the values of each sample are plotted with the elastic modulus on the X-axis and the elastic limit strain on the Y-axis for the measured values with a plunger diameter of 3 mm. Compared with the figure of 8 mm, there is a difference in the value of the elastic limit strain, and it is possible to evaluate the texture of the meat more finely.

(Comparative Example 1) A uniaxial constant velocity intrusion test was performed by the method of Example 1 except that the measured moving speed based on the breaking strength was 1.0 mm / s, and the stress obtained-the stress at the breaking point in the strain curve. The breaking strength was calculated from the size. The breaking stress of each sample is shown in Table 3 below.

FIG. 6 is a graph showing stress-strain curves for the representative samples of each sample in Comparative Example 1, but as shown in Table 3 and FIG. 6, the breaking strength, which is a conventional analysis item, has a fine texture of meat. Is difficult to evaluate.

Claims (1)

Using a uniaxial compression tester, a cylindrical plunger with a diameter of 3 to 8 mm is moved at a constant speed of 0.05 to 1.0 mm / s to press the food, and the elastic modulus and elastic limit strain are reduced. A method for evaluating the texture of a food, which comprises analyzing and evaluating the texture of the food on a two-axis graph with the elastic modulus and the elastic limit strain as axes.

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