RU2346272C2 - Method for determining quality of meat - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention concerns the instrumentation used in cattle breeding, in particular for examination and analysis of meat quality by means of optics. Method involves measuring the intensity of light flux reflected from the meat using a dedicated photometer "ЦФМ-2СД", which has a measuring section in the form of a sensing head, which is separable from the housing and fitted with a lighting chamber, photodetector and window for application to the surface to be measured. Meat or carcass colour is recorded and in accordance with colour intensity meat is classified into relevant quality categories.

EFFECT: quicker and easier measurement of meat colour with high measurement accuracy both in laboratory and production conditions during animal slaughtering and meat selling.

2 dwg

Description

1. The technical field

The invention relates to the field of research and analysis of materials by determining their physical properties, in particular to determining the quality of meat on the basis of measuring the intensity of its color using a specially designed optical device - color meter CFM-2SD.

The purpose of the invention is the acceleration and simplification of determining the quality of meat by its color while maintaining high accuracy of measurement of the studied indicator in both laboratory and industrial conditions when slaughtering animals and selling meat.

This goal is achieved by measuring the intensity of the head and the light flux reflected from the surface of the meat in comparison with the reference using a photocurrent initiated by a photodetector located in the head of the sensor, the size of which, after appropriate conversion in the electronic unit, determines the quality of the meat.

2. Description of analogues (methods)

There are various methods for determining the quality of meat by its color by measuring the intensity of its color using various technical means, namely:

2.1. The meat quality is determined by measuring the color intensity of a specially prepared liquid meat extract in comparison with the standard on an SF-10 recording spectrophotometer. The device is a rather bulky and complex device (the weight of the device is 380 kg, dimensions 1150 × 960 × 380 mm) requires a sufficiently long special preparation of a liquid medium for the study of meat samples taken under strictly stationary conditions (Spectrophotometer recording SF-10. Description and manual for user. 1961, p. 2-8).

2.2. High accuracy in determining the quality of meat by the intensity of its color can be obtained using a KFK-2 photoelectric concentration meter-colorimeter designed to measure in individual parts of the wavelength range 315-980 nm. The principle of measuring the transmittance with the help of this device is that light streams are sent alternately to the photodetector - full Foj through the standard solution and Fj - through a specially prepared meat hood and the intensity of the color of the meat is determined from these streams.

The disadvantage of this device for determining the quality of meat by its color is the sufficient complexity of both the device itself and the preparation of a sample for research and the ability to work in strictly limited stationary conditions (Colorimetric photometric concentration KFK-2. Technical description and operating instructions. 1990)

2.3. A device is known for determining the color of a sample by transmitted or reflected light (UK Patent No. 1072363, class G01N 21/00, 1967) /, including a light bulb, a filter on a rotating disk, a beam splitting structure, a variable and adjustable attenuator, a system mirrors, photocells. After calibration, the prototype is set to the appropriate position and the slot is adjusted to balance the bridge for each filter in turn. The amount of reflected or transmitted light is read from the penetrating light control scale. The device can be used to control such a material that maintains a constant color and in strictly stationary conditions.

2.4. A setup was developed for determining the color of samples with a control head and with a lifting stage, within which a control head hangs, and under it is a table for placing samples. The control head consists of a body of transparent material and a cylindrical chamber open at the bottom, the lower surface of which is covered by a glass plateau. The first light beam passes in the direction of the axis of the cylindrical chamber, the second light beam enters the chamber at angles of 45 ° to the axis of the cylinder. The installation works only in stationary conditions and on specially prepared samples (Germany, application No. 2636420, class G01N 21/00, 1977).

2.5. The closest to the device used in the proposed method according to the technical essence and the achieved effect is a device for measuring the reflection coefficient SU 960544, cl. G01N 21/47, 1982). The device comprises a measuring head connected to a signal processing unit. The measuring head has an inlet closed by a transparent plate, and inside the measuring head there is a illuminator and a collective lens, a light filter and a photodetector along the radiation path. To determine the reflection coefficient, a sensor head is applied to the surface of the measured object. The signal from the measured head, proportional to the measured reflection coefficient, is fed through the amplifier to the voltage-frequency converter. After appropriate signal processing and its conversion and averaging, an averaged indicator is issued to the counter during repeated measurements of the reflection coefficient of nonuniformly reflecting surfaces. The scope of this device is solid materials with a non-uniformly reflecting surface and layers between them, which makes it unacceptable for directly measuring the color of meat and determining its quality both in laboratory and in production conditions.

3. Description of the prototype

As a prototype taken the invention SU 1244589 A1, class. G01N 33/12, 1986). “Method for determining the quality of meat”, which provides for the preparation of a sample and measuring a parameter characterizing its quality, characterized in that in order to accelerate and reduce the complexity, the reflection coefficient of a specially prepared meat sample is measured at two wavelengths - 480-520 and 640-720 nm, and meat quality is determined by the ratio of measured values according to a special formula. The meat quality is practically determined on a meat sample cut in the form of a cylinder with a diameter of 50 mm and a height of 6 mm. Thus, the prepared meat sample is placed in the measuring unit of the SF-10 stationary spectrophotometer and the reflection curve is taken in the range 400-700 nm. The curve is processed on the two wave ranges indicated above and the quality of the meat is determined by the formula.

The disadvantage of this method for determining the quality of meat is the requirements for special preparation of a meat sample and measuring the intensity of its reflection on two wavelengths on a rather complex and stationary spectrophotometer SF-10 and the subsequent calculation of meat quality using a special formula, on the one hand, and the complexity and inability to use it production conditions for slaughtering animals and selling meat, on the other.

4. The technical problem and technical results

Currently, the color intensity (color) and determination of meat quality on its basis is carried out by:

1. It is quite difficult to extract pigments from meat with the help of special chemical solvents and subsequent measurement on fairly complex and mostly stationary photocolorimetric devices.

2. Measurement of the intensity of reflected light from the surface of specially prepared meat samples using fairly complex and bulky photocolorimetric installations.

3. The process of measuring the intensity of coloring (color) of meat and determining its quality on this basis is quite complex, time-consuming and, most importantly, does not allow this to be done directly on the carcasses of killed animals and during the sale of meat.

The main technical task of the proposed method for determining the quality of animal meat was to eliminate the above disadvantages, namely the impossibility of measuring the intensity of color (color) and determining on this basis the quality of meat directly on carcasses in a production environment or on meat samples without their preliminary preparation in laboratory conditions, minimizing (3-5 seconds) the measurement duration, and at the same time maintain high measurement accuracy.

These technical problems were solved with the help of a developed, built and tested device for determining the color intensity (color) of meat - the TsFM-2SD color photometer, free from these drawbacks, characterized by the speed of measurement (3-5 seconds per measurement), sufficient simplicity and ease of use and the possibility of application both in laboratory conditions on samples that do not require special preparation, and in production conditions for slaughtering animals and selling meat, while maintaining high accuracy of measurement rhenium.

5. A statement of the method for determining the quality of meat (methods for determining the quality of meat)

The quality of animal meat is determined using a specially designed, built and tested device - a colorimeter TsFM-2SD.

5.1. The characteristic of the device. A General view of the colorimeter TsFM-2SD and the basic electrical block diagram with the corresponding element base are presented in figures 1 and 2.

Device Color Photometer TsFM-2SD (figure 1) consists of a sensor head 1 and an electronic measuring device with a mains and battery 2.

The sensor head (1) includes: a photocell (7) with a working wavelength range of 350-750 nm for receiving reflected light from the measured meat surface, four 2.5 V lamps each (5), connected in series, placed in the lighting the camera of the sensor head with a special round glass-glazed optical hole with a window diameter of 36 mm (8) with a cover and a push-button switch to turn on the surface lighting at the time of measurement (10).

An electronic measuring device placed in a special case (2) is designed to convert the electromotive force (EMF) of the photocell (7) and then measure and transmit it to the recording device (9). At the same time, the mains and battery packs are located in the case, which ensures the supply of a strictly stabilized voltage regardless of fluctuations in the mains voltage or a drop to a certain level of battery voltage. This ensures stable illumination of the measured surface and the operation of the electronic measuring device. The measurement results are recorded using a microammeter with a scale division from 1 to 100 units (9). On the surface of the instrument panel are installed: a microammeter (9), a variable resistor knob to set the microammeter arrow by dividing 100 according to a white standard (12), a control lamp (11), a device toggle switch (10). On the right side of the case there are connectors for connecting the sensor head plug and the housing with a three-core soft cable and an electric cord with a plug at the end for mains voltage.

5.2. The principle of operation of the device. The signal - the emf of the photocell from the sensor head is fed to a differential amplifier of the type K153UD2, assembled according to the standard common circuit (OC) circuit. Feedback resistance selected 220 kOhm. A measuring microammeter is connected between the OC output to the differential amplifier and the common wire. The power supply to the common circuit is stabilized by two voltage zener diodes. The supply voltage is OC ± 15 V, the lighting lamps are 10 V. The lamps are connected in series by a common wire. The microammeter is protected against overload by two diodes. Turn on the device for 10-15 minutes before starting work.

Before measuring the color of meat, the pointer of the microammeter according to the white standard is mounted on the division 100 using the variable resistor knob. To do this, put the cover of the sensor head, on the inside of which there is a white standard, put on the window of the sensor head, turn on the light and set the pointer of the microammeter to division 100. After that, the device is ready for operation.

Meat color measurement on carcasses or laboratory samples is carried out by applying a hole-window to the measured surface and turning on the lighting in the sensor head. The intensity of the reflected light from the standard is taken as 100%, and the intensity of the reflected light from the measured surface of the meat is fixed as a percentage relative to the standard.

5.3. The characteristic of the device. 1. Appointment. The device - a color photometer TsFM-2SD is designed to measure the color intensity (color) of meat of farm animals after their slaughter and can work both in laboratory and production conditions to identify the quality of meat. 2. Technical data. The measuring range is from 5 to 100%. The scale division price is 1%. The device is set to division 100 according to a white reference sample. The margin of error is -1%. The duration of one measurement is 3-5 seconds. Overall dimensions 200 × 150 × 100 mm. Weight - 1.2 kg.

5.4. The device used to determine the quality of meat was tested when slaughtering large white pigs at the Naro-Fominsk meat processing plant in the Moscow Region and Estonian bacon pigs at the meat processing plant in Parny (Estonia).

On each carcass, the pH and color of the meat was measured with a TsFM-2SD color photometer. According to the results of the analysis of the data obtained, meat was divided into three quality categories: normal meat, meat with PSE and meat with DFD. The final results of the distribution of carcasses into qualitative categories according to the results of pH and color are presented in table 1.

Table 1 PH and color boundary parameters for quality meat categories Meat quality categories By pH: By color of meat,%: Normal meat 5.50-6.10 30-37 Meat with vice PSE 4.0-5.49 38 and more DFD meat 6.20-7.70 29 and less

The average pH and color of meat in the distribution of carcasses according to the boundary quality parameters 24 hours after slaughter are presented in table 2.

table 2 Average pH and color of meat in the distribution of carcasses according to the boundary parameters of the quality categories of meat Meat quality categories By pH By color quantity: quantity carcass %: M ± m carcass %: M ± m Normal meat 69 70.50 5.73 ± 0.02 71 77.20 34.6 ± 0.40 Meat with vice PSE fourteen 15.60 5.39 ± 0.02 fifteen 16.30 39.7 ± 0.64 DFD meat 9 9.78 6.43 ± 0.11 6 6.50 28.6 ± 0.47

From the data of table 2 it follows that the carcasses of animals with a lower pH of 5.2 (PSE defect) and a higher pH of 6.43 (DFD defect), respectively, had more and more - 39.7% (PSE defect) and less - 28.6% (DFD defect) value of meat color index. The number of carcasses assigned to certain categories of meat quality by pH is exactly the same as the number of carcasses assigned to separate categories of meat quality according to the actual value of the meat color index. The normal meat quality was 75.0 and 77.2%, respectively, in pH and color, with PSE defect 15.2 and 16.3% and DFD defect - 9.78 and 6.5% carcasses. The correlation coefficients between pH and color of meat were respectively -0.91 and -0.86 in pigs of large white and Estonian bacon breeds.

Thus, experimental tests of the proposed method for determining the quality of meat using a colorimeter TsFM-2SD in comparison with qualitative identification with pH showed its high accuracy

Compared with prototypes and an analogue, the claimed method for determining the quality of meat using a specially created colorimeter TsFM 2SD is more efficient in operation - it takes 3 to 5 seconds per measurement, it does not require special preparation of samples for research, it allows to obtain high-precision information about quality meat both on samples in laboratory and directly on carcasses of animals in the production conditions of their slaughter and sale of meat.

Claims (1)

A method for determining the quality of meat, which consists in measuring the intensity of the light flux reflected from the meat using a photodetector, the magnitude of which determines the quality of the meat, characterized in that the intensity of the light flux reflected from the white standard is measured using a photodetector, the spectral range of which is 350-750 nm and which is placed in the sensor head, which also contains a lighting chamber and a hole-window, applied to the surface under study, and connected by a cable to the housing of the device in which The electronic amplification and conversion of the photocurrent signal and the stabilized power supply unit take the intensity of the light flux reflected from the white standard equal to 100%, and the intensity of the reflected light flux from the measured meat surface is fixed as a percentage relative to the standard, while the meat is divided into quality categories : normal - 30-37%, defective with a PSE defect - 38% or more and with a DFD defect - 29% or less.

Images