Apparatus and method for measuring fatty acid composition ratio of fat

Abstract

To measure a component ratio of fatty acid in fat in a living body.SOLUTION: The measuring system has (A) a nuclear magnetic resonance sensor including a magnetic circuit and a high-frequency coil, and (B) a measuring unit which outputs a predetermined high-frequency pulse to the high-frequency coil, obtains a proton transverse relaxation waveform of a living body from the high-frequency coil, calculates a transverse relaxation time of fat included in a predetermined model equation by regression analysis on data on the proton transverse relaxation waveform, and calculates an amount ratio of unsaturated fatty acid of a living body based on the calculated transverse relaxation time of fat and data on a calibration curve prepared in advance.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a technique for measuring the fatty acid composition ratio of fat in a living body. [Background technology]

[0002] Low-field time-domain proton nuclear magnetic resonance (NMR) techniques (e.g., Patent Documents 1-3 and Non-Patent Document 1) are known as a non-destructive, non-invasive, in-situ method for measuring the physicochemical state of water, oil, rubber, gel, and other substances inside objects. Specifically, these techniques can be applied to deep underground oil field logging (e.g., Non-Patent Document 1), measuring the degree of marbling in live cattle (e.g., Non-Patent Document 2), and measuring the fat content of fatty tuna (e.g., Non-Patent Document 3). For example, the fat content of foods such as beef and tuna is an important characteristic that directly affects their taste and ultimately their price. Therefore, this technique, which enables in-situ, non-destructive, and non-invasive measurement, is a promising measurement technology.

[0003] The measurement principle of this proton nuclear magnetic resonance method is roughly as follows. As shown schematically in Figure 1, first, the object to be measured (in this case, a living cow) is brought close to the sensor (including a magnetic circuit and a radio-frequency coil) with an open end so that it falls within the sensor's sensitivity range. Note that the sensitivity range is set several millimeters to several centimeters below the surface of the object, depending on the design and size of the magnetic circuit and the distance between the object and the coil. A series of radio-frequency pulses, for example, known as the Carr-Purcell-Meiboom-Gill (CPMG) method, is applied to the radio-frequency coil (see, for example, Non-Patent Document 1). The magnetic field waves generated by these pulses excite protons in water, oil, etc. in the sensitivity range, and the subsequent transverse relaxation process of the protons is detected by the radio-frequency coil as a transient CPMG waveform f(t) (also called the proton transverse relaxation waveform). Note that t represents time. Protons in fatty hydrocarbons and protons in water (water in lean meat, i.e., muscle) often have different transverse relaxation times T2 (e.g., Non-Patent Document 4). Therefore, by utilizing this difference in proton transverse relaxation time (T2), we are able to perform non-destructive and non-invasive quantitative measurement of the fat content of marbled meat.

[0004] According to the general public's meat preferences, not only the fat content of marbled meat but also the quality of the fat, i.e., differences in fat constituents, are important characteristics that govern the taste and ultimately the price of meat (e.g., Non-Patent Document 5). Fatty acids are the main constituents of fat and are classified as saturated or unsaturated fatty acids depending on whether or not they contain a carbon-carbon double bond. Unsaturated fatty acids, which have double bonds, generally have a lower melting point than saturated fatty acids, and meat with a high content of unsaturated fatty acids melts easily in the mouth, has a soft texture, and is easy to eat. Because unsaturated fatty acids have such a strong influence on the flavor of meat, meat with a high content of unsaturated fatty acids is expensive, and various inventions, such as innovative feed, have been developed (e.g., Patent Documents 4 and 5).

[0005] However, there is no measurement method that can accurately quantify the relative ratio of saturated fatty acids to unsaturated fatty acids (i.e., fatty acid composition ratio) in the fat of living organisms such as beef cattle in a non-destructive and non-invasive manner. For example, near-infrared spectroscopy can quantify the relative ratio of saturated fatty acids to unsaturated fatty acids by applying a near-infrared sensor to the cross section of the meat in the case of a cut surface of a carcass (exposed meat) (e.g., Non-Patent Document 6), but it is difficult to perform non-destructive and non-invasive analysis of subcutaneous fat through the hair and skin of living cattle, which absorb and scatter near-infrared light and hinder accurate measurement.

[0006] To develop methods for fattening livestock that sell at high prices, i.e., livestock that are high in unsaturated fatty acids, it is inefficient to slaughter each animal and measure the cross-section of the carcass using near-infrared spectroscopy. It is more efficient to perform non-destructive and non-invasive measurements of living organisms in ranches or barns continuously over several years, from calves to adult cattle just before shipping, and carefully analyze the effects of factors such as bloodline, exercise, and the quality and quantity of feed. Thus, there is a need for a method for accurately measuring the relative ratio of saturated and unsaturated fatty acids in living organisms in a non-destructive and non-invasive manner. Note that while the above discussion focuses on cattle, the same applies to pigs and other livestock. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent No. 5196480 [Patent Document 2] Japanese Patent No. 5294230 [Patent Document 3] Japanese Patent No. 5170617 [Patent Document 4] Japanese Patent No. 4226644 [Patent Document 5] Patent Publication No. 2012-143227 [Non-patent literature]

[0008] [Non-Patent Document 1] Casanova, Federico, Juan Perlo, and Bernhard Bluemich (eds.). (2011). "Single-sided NMR." Springer, Berlin, Heidelberg. [Non-patent document 2] Nakashima, Yoshito. (2015). "Development of a single-sided nuclear magnetic resonance scanner for the in vivo quantification of live cattle marbling." Applied Magnetic Resonance 46, 593-606. [Non-patent document 3] Nakashima, Y. (2019) “Non-Destructive Quantification of Lipid and Water in Fresh Tuna Meat by a Single-Sided Nuclear Magnetic Resonance Scanner” Journal of Aquatic Food Product Technology 28, 241-252. [Non-patent document 4] Nakashima, Y., and Shiba, N. (2021) “Nondestructive measurement of intramuscular fat content of fresh beef meat by a hand-held magnetic resonance sensor”, International Journal of Food Properties, 24(1), 1722-1736. [Non-Patent Document 5] Irie, M. (2021). Fat quality and eating quality of Wagyu beef. Bulletin of the Japanese Society of Animal Science, 92(1), 1-16 [Non-patent document 6] Irie, M. (2019). Evaluation of beef fat quality using near-infrared optical fiber spectroscopy and its application. Meat Science, 60(2), 219-226. [Non-Patent Document 7] Nakajima, Y. (2015). Can NMR be used to determine the marbling of beef? Chemistry, 70(11), 25-28. [Non-patent document 8] Nakajima, Y. (2002). Measurement of water self-diffusion coefficient using pulsed magnetic field gradient NMR: Principle and application to clay gels. Clay Science, 42(1), 37-50. [Non-Patent Document 9] Ministry of Education, Culture, Sports, Science and Technology (2015). Japanese Food Standard Composition Table 2015 Edition (7th Edition) Analysis Manual [Non-Patent Document 10] Zverev, LV, Prudnikov, SM, Vityuk, BY, Dzhioev, TE, and Panyushkin, VT (2001). Determination of the main fatty acids in sunflower-seed oil by a nuclear magnetic relaxation technique. Journal of Analytical Chemistry, 56(11), 1029-1031. [Non-Patent Document 11] Nishioka, T., Ishizuka, Y., Yasumatsutani, K., and Irie, M. (2008). Relationship between palatability and physicochemical properties of beef fat in markets and retail stores. Bulletin of the Japanese Society of Animal Science, 79(3), 391-401. Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, one aspect of the object of the present invention is to provide a technique that enables measurement of the fatty acid composition ratio of fat in a living body. [Means for solving the problem]

[0010] The measurement system according to the present invention includes: (A) a nuclear magnetic resonance sensor including a magnetic circuit and a high-frequency coil; and (B) a measurement unit that outputs a predetermined high-frequency pulse to the high-frequency coil, acquires a proton transverse relaxation waveform for a living animal from the high-frequency coil, calculates the transverse relaxation time for fat included in a predetermined model formula by regression analysis of the data on the proton transverse relaxation waveform, and calculates the quantitative ratio of unsaturated fatty acids for the living animal based on the calculated transverse relaxation time for fat and data on a calibration curve prepared in advance. [Effects of the Invention]

[0011] According to one aspect, it becomes possible to measure the fatty acid composition ratio of fat in a living body. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a scene in which a nuclear magnetic resonance sensor is placed on a living cow to perform measurements. [Figure 2] FIG. 2 is a diagram showing an example of the positional relationship between parts of a living cow and the sensitivity region of a nuclear magnetic resonance sensor. [Figure 3A] FIG. 3A is a diagram showing an example of a CPMG waveform. [Figure 3B] FIG. 3B is an enlarged example of the CPMG waveform shown in FIG. 3A. [Figure 4] FIG. 4 is a diagram showing a calibration curve for the oleic acid content (%). [Figure 5] FIG. 5 shows a calibration curve for the total unsaturated fatty acid content (%). [Figure 6] FIG. 6 shows a calibration curve for monounsaturated fatty acid content (%). [Figure 7] FIG. 7 is a diagram for evaluating the error regarding the oleic acid content (%). [Figure 8] FIG. 8 is a diagram for evaluating the error in the unsaturated fatty acid content (%). [Figure 9] FIG. 9 is a diagram for evaluating the error in the monounsaturated fatty acid content (%). [Figure 10] FIG. 10 is a diagram illustrating an example of the configuration of a measurement system. [Figure 11] FIG. 11 is a diagram showing a processing flow of the measurement system. [Figure 12] FIG. 12 is a diagram showing an example of the positional relationship between parts of a living cow and the sensitivity region of a nuclear magnetic resonance sensor. [Figure 13] FIG. 13 is a block diagram of a computer device. DETAILED DESCRIPTION OF THE INVENTION

[0013] [First embodiment of the present invention] [overview] In an embodiment of the present invention, a single-sided open-type proton nuclear magnetic resonance (NPR) method, as shown in FIG. 1, is used to nondestructively and noninvasively measure the constituent components of subcutaneous fat, specifically the relative ratio of saturated and unsaturated fatty acids, through the hair and skin of a measurement target, i.e., a living livestock (e.g., a cow). As shown in FIG. 2, livestock have a layered structure consisting of hair, skin, subcutaneous fat with almost no muscle, and muscle (or, in some cases, marbled meat). The sensitivity region of the NPR sensor 200, which includes a magnetic circuit and a high-frequency coil, is set several millimeters to several centimeters below the surface of the livestock. Therefore, by appropriately separating the NPR sensor 200 from the livestock, the sensitivity region can be overlapped with the subcutaneous fat. It is known that the single-sided open-type NPR method is, in principle, not affected by the skin or hair near the body surface (e.g., Non-Patent Document 3).

[0014] The CPMG waveform f(t) of pure fat that does not contain muscle (red meat) is expressed by the following model: The CPMG waveform is also called the proton transverse relaxation time waveform. f(t)=Afat*exp(-t / T2fat) (1) Afat and T2fat are unknown constants to be determined by fitting using the least squares method or the like. However, Afat is the signal intensity when extrapolated to time zero, and increases in proportion to the amount of fat in the sensitivity region of the nuclear magnetic resonance sensor 200. On the other hand, T2fat is the transverse relaxation time of fat, and is a physical property value associated with the microscopic mobility of fat molecules.

[0015] In conventional techniques, including Non-Patent Document 4, the transverse relaxation time T2fat was treated as a constant, although it was dependent on temperature. However, a new and unobvious finding was obtained that the transverse relaxation time T2fat value in Equation (1) is strongly correlated with the relative amount of unsaturated fatty acids, such as oleic acid. Therefore, if the transverse relaxation time T2fat is assumed to be an unknown quantity and determined using regression analysis such as the least squares method, it becomes possible to convert the transverse relaxation time T2fat value of the subcutaneous fat of living livestock (the area of ​​subcutaneous fat directly below the body surface, with almost no muscle (lean meat)) into the relative amount of unsaturated fatty acids. This will contribute to the development of an efficient method for fattening livestock that contains a large amount of unsaturated fatty acids. The nuclear magnetic resonance sensor 200 is connected to the measuring device 100, which calculates the transverse relaxation time T2fat value from the CPMG waveform f(t) and calculates the relative quantitative ratio of unsaturated fatty acids corresponding to the calculated transverse relaxation time T2fat value from a calibration curve for the transverse relaxation time T2fat.

[0016] [experiment] A total of 12 beef tallow samples (pure fat samples that do not contain muscle (lean meat), such as subcutaneous fat or intermuscular fat near the loin) were obtained from retailers and each was divided into aliquots for nuclear magnetic resonance analysis and fatty acid composition analysis. The aliquots were analyzed using the following method to verify the hypothesis that the T2fat value of beef tallow samples is strongly correlated with the relative amount of unsaturated fatty acids.

[0017] [About nuclear magnetic resonance analysis] Since this experiment envisions non-invasive and non-destructive measurements on live livestock (cattle), the beef tallow samples were tested at a temperature (40°C) that is the same as the internal temperature of the cow. However, with a one-sided open-type nuclear magnetic resonance instrument, the sample is exposed to the external environment (laboratory room temperature, approximately 20°C), making it difficult to maintain the beef tallow sample at a high temperature of 40°C. Therefore, this experiment used a conventional instrument (bilateral type; see, for example, Non-Patent Documents 7 and 8) that facilitates precise temperature control. Note that bilateral nuclear magnetic resonance instruments are in the same category as one-sided open-type nuclear magnetic resonance instruments in the sense that they are low-field time-domain proton nuclear magnetic resonance instruments.

[0018] The beef fat sample was sealed in a 1 mL glass sample tube and loaded into a temperature-controlled bilateral nuclear magnetic resonance spectrometer. The CPMG waveform f(t) of fat was measured using the CPMG method with an echo interval of 1 ms. Equation (1) was fitted to the measured f(t) data using the least squares method, etc., to calculate Afat and T2fat.

[0019] [Fatty acid composition analysis] The fatty acid composition of the fat sample (approximately 20 g) was analyzed using the official food analysis method designated by the Ministry of Education, Culture, Sports, Science and Technology (gas chromatography using a flame ionization detector) (see, for example, Non-Patent Document 9). This analysis revealed the relative weight fractions of saturated fatty acids such as palmitic acid, stearic acid, and myristic acid, and unsaturated fatty acids such as oleic acid, palmitoleic acid, and linoleic acid. Below, the weight fraction of unsaturated fatty acids is discussed using three indicators: the weight fraction of oleic acid, the weight fraction of total unsaturated fatty acids, and the weight fraction of monounsaturated fatty acids. Oleic acid was selected because it is the main unsaturated fatty acid in beef tallow, accounting for approximately 40% of the total fatty acids. Total unsaturated fatty acids include all unsaturated fatty acids detected by gas chromatography, such as oleic acid, palmitoleic acid, and linoleic acid. Furthermore, monounsaturated fatty acids are unsaturated fatty acids with only one carbon-carbon double bond, such as oleic acid and palmitoleic acid.

[0020] [Experimental Results] Examples of the CPMG waveforms obtained for the two beef tallow samples are shown in Figures 3A and 3B. The vertical axis represents CPMG signal intensity, and the horizontal axis represents time. In practice, CPMG waveform data was sampled every 1 ms, but for clarity, the figures plot every 10 ms. Open squares represent plots for sample S1, and filled circles represent plots for sample S2. The curve resulting from fitting sample S1 using the least squares method of equation (1) is shown by a solid line, and the curve resulting from fitting sample S2 using the least squares method of equation (1) is shown by a dotted line. Note that Figure 3B is an enlarged view of Figure 3A up to 400 ms. The oleic acid content, total unsaturated fatty acids, and monounsaturated fatty acids of sample S1 were 34.3%, 40.3%, and 37.9%, respectively, and the oleic acid content, total unsaturated fatty acids, and monounsaturated fatty acids of sample S2 were 50.4%, 58.8%, and 55.5%, respectively. In addition, the transverse relaxation time T2fat value obtained by fitting equation (1) to sample S1 was 141 ms, and the transverse relaxation time T2fat value obtained by fitting equation (1) to sample S2 was 177 ms.

[0021] These results indicate that beef tallow with a relatively high content of unsaturated fatty acids, such as oleic acid, which has a low melting point, has a longer transverse relaxation time T2fat, i.e., the CPMG waveform decays more slowly. This positive correlation was first discovered in this beef tallow measurement experiment. It is known that, even with the same oleic acid content, the oleic acid content of sunflower seed oil shows a negative correlation with the transverse relaxation time T2fat; that is, the higher the oleic acid content of sunflower oil, the shorter the transverse relaxation time T2fat estimated by equation (1) (see, for example, Non-Patent Document 10).

[0022] Figure 4 shows the relationship between the oleic acid content (%) and the transverse relaxation time T2fat value for 12 beef tallow samples, as determined by food analysis. Figure 5 shows the relationship between the total unsaturated fatty acid content (%) and the transverse relaxation time T2fat value for the same beef tallow samples, as determined by food analysis. Figure 6 shows the relationship between the monounsaturated fatty acid content (%) and the transverse relaxation time T2fat value for the same beef tallow samples, as determined by food analysis. The straight lines shown in Figures 4 to 6 are approximate straight lines for the plots and serve as calibration curves. The correlation coefficients in Figures 4 to 6 are high, at 0.91, 0.92, and 0.93, respectively, indicating a high positive correlation between the measurement results of the transverse relaxation time T2fat and the fatty acid composition analysis results.

[0023] Figure 7 shows the relationship between the oleic acid content (%) obtained by converting the transverse relaxation time T2fat values ​​using the linear calibration curve shown in Figure 4 and the oleic acid content (%) obtained by food analysis. Figure 8 shows the relationship between the total unsaturated fatty acid content (%) obtained by converting the transverse relaxation time T2fat values ​​using the linear calibration curve shown in Figure 5 and the total unsaturated fatty acid content (%) obtained by food analysis. Figure 9 shows the relationship between the monounsaturated fatty acid content (%) obtained by converting the transverse relaxation time T2fat values ​​using the linear calibration curve shown in Figure 6 and the monounsaturated fatty acid content (%) obtained by food analysis. In these cases, the root mean square errors were 2.2%, 2.8%, and 2.6%, respectively. These results are comparable to those obtained by near-infrared spectroscopy (measurements of the cross section of beef carcasses yielded an error of approximately 2%; see, for example, Non-Patent Document 6), and are considered to be favorable results.

[0024] Figures 4 through 6 support the hypothesis that the T2fat value of beef tallow samples is strongly positively correlated with the relative proportions of unsaturated fatty acids. Figures 7 through 9 show that the estimation error for the proportion of oleic acid by nuclear magnetic resonance is 2.2%, the proportion of total unsaturated fatty acids is 2.8%, and the proportion of monounsaturated fatty acids is 2.6%. These errors are comparable to the errors of near-infrared spectroscopy for bare carcass cross-sections, providing favorable results. While near-infrared spectroscopy is difficult to measure through the hair or hide of live cattle, a single-sided open-type nuclear magnetic resonance instrument can measure subcutaneous fat through the hair or hide of live cattle.

[0025] [Configuration of the First Embodiment] The nuclear magnetic resonance apparatus according to this embodiment includes a nuclear magnetic resonance sensor 200 as shown in Fig. 2, and a measuring device 100 connected to the nuclear magnetic resonance sensor 200. As shown in Fig. 10, the measuring device 100 includes a transverse relaxation time measuring unit 110 that measures the transverse relaxation time T2fat, a calibration curve generating unit 120 that generates a calibration curve for unsaturated fatty acids, a data storage unit 130 that stores data representing the calibration curve, and an analyzing unit 140 that calculates the quantitative ratio of unsaturated fatty acids corresponding to the measured transverse relaxation time T2fat value.

[0026] The transverse relaxation time measurement unit 110 calculates the transverse relaxation time T2fat by fitting equation (1) to the CPMG waveform f(t) input from the nuclear magnetic resonance sensor 200, for example, using the least squares method. The calibration curve generation unit 120 is not necessary when calibration curve data is provided externally. However, when generating calibration curve data, the calibration curve generation unit 120 acquires the transverse relaxation time T2fat value from the transverse relaxation time measurement unit 110 for each of multiple samples with known quantitative ratios of unsaturated fatty acids, and generates calibration curve data as shown by the straight lines in Figures 4 to 6 from the quantitative ratios of unsaturated fatty acids and the corresponding transverse relaxation time T2fat values, and stores the data in the data storage unit 130. The calibration curve data may be table-like data in which the quantitative ratios of unsaturated fatty acids are associated with each of multiple transverse relaxation time T2fat values, or may be linear mathematical formula data representing the calibration curve. The analysis unit 140 derives and outputs the quantitative ratio of unsaturated fatty acids for the livestock being measured from the transverse relaxation time T2fat value for the livestock being measured acquired from the transverse relaxation time measurement unit 110 and the calibration curve data stored in the data storage unit 130. The unsaturated fatty acids are at least one of oleic acid, total unsaturated fatty acids, and monounsaturated fatty acids, but may also be any other unsaturated fatty acid of interest.

[0027] The processing details of the measurement device 100 will be described using FIG. 11. First, the transverse relaxation time measurement unit 110 measures the transverse relaxation time T2fat from the CPMG waveform f(t) for multiple samples with known unsaturated fatty acid ratios. The calibration curve generation unit 120 generates a calibration curve from the measurement results and the known unsaturated fatty acid ratios, for example, by linear fitting using the least squares method, and stores the calibration curve in the data storage unit 130 (step S1). Note that the sample with a known unsaturated fatty acid ratio may also be a sample from which the unsaturated fatty acid ratio will be obtained later. For example, after acquiring the CPMG waveform f(t) from a living livestock in a state as shown in FIG. 2 using the nuclear magnetic resonance sensor 200 and measuring the transverse relaxation time T2fat, the livestock may be slaughtered and the unsaturated fatty acid ratio measured for the subcutaneous fat, etc., using another method. Note that, as in the above-mentioned experiment, a sample such as subcutaneous fat without muscle may also be used. Note that if calibration curve data is provided externally, step S1 is skipped.

[0028] Next, the transverse relaxation time measurement unit 110 measures the transverse relaxation time T2fat from the CPMG waveform f(t) output by the nuclear magnetic resonance sensor 200 for the livestock being measured (step S3). As described above, the transverse relaxation time T2fat is calculated by fitting equation (1) using the least squares method or the like. Thereafter, the analysis unit 140 calculates the quantitative ratio of unsaturated fatty acids corresponding to the measured transverse relaxation time T2fat based on the calibration curve data stored in the data storage unit 130, and outputs the calculated ratio to an output device such as a display device or printer (step S5). The quantitative ratio of saturated fatty acids may also be calculated as (100% - the quantitative ratio of all unsaturated fatty acids).

[0029] In this way, the use of a single-sided open-ended nuclear magnetic resonance spectrometer makes it possible to obtain the ratio of unsaturated fatty acids in living livestock nondestructively and noninvasively. This is expected to contribute to the development of fattening methods for livestock such as cattle, which contain high amounts of unsaturated fatty acids with high market value. Furthermore, as mentioned above, the measurement accuracy of the ratio of unsaturated fatty acids is sufficiently high and reliable, comparable to that of conventional technology.

[0030] Scanning a live cow using the setup shown in Figure 2 provides information on the fatty acid composition of the subcutaneous fat. However, the main edible part of beef is the marbling muscle (marbled meat) located deeper than the subcutaneous fat. Therefore, information on the fatty acid composition of the subcutaneous fat layer, which is an anatomically distinct part, does not directly provide information on the fatty acid composition of the edible part. Fortunately, however, there is a correlation between the fatty acid composition of the subcutaneous fat and that of the fat in edible parts such as the loin (see Non-Patent Document 11). Therefore, if information on the fatty acid composition of the subcutaneous fat can be obtained using the measurement shown in Figure 2, it is possible to scientifically estimate the fatty acid composition of the fat in edible parts such as the loin. However, it is also possible to directly acquire CPMG waveforms of the edible marbling muscle by reconfiguring the sensor to a deeper detection depth than that shown in Figure 2.

[0031] [Embodiment 2] In the first embodiment, the nuclear magnetic resonance sensor 200 was placed a little distance away from the body surface of the livestock, with the sensitivity region overlapping the subcutaneous fat portion, as shown in Fig. 2. However, the nuclear magnetic resonance sensor 200 may be placed closer to the body surface of the livestock, with the sensitivity region overlapping the muscle portion in a fat-mixed state (marbled state), as shown in Fig. 12. In this case, the CPMG waveform f(t) is a superposition of signals derived from two types of protons, fat molecules and water molecules in the muscle (lean meat), and therefore should be modeled by the following equation (2) instead of equation (1). f(t)=Afat*exp(-t / T2fat)+Alean*exp(-t / T2lean) (2) Here, the first term on the right side is the same as in Equation (1), but Alean in the second term on the right side is an unknown constant to be determined by the least squares method or the like, which increases in proportion to the amount of lean meat in the sensitivity range of the nuclear magnetic resonance sensor 200, and T2lean in the second term on the right side is the transverse relaxation time T2 value derived from water molecules in muscle, which can be obtained by measuring a pure muscle sample without fat in advance. That is, T2lean is calculated in advance by a separate measurement, and Afat, T2fat, and Alean are calculated by the least squares method or the like.

[0032] Equation (2) itself is also shown in Non-Patent Documents 2 to 4, but the present embodiment differs in that the transverse relaxation time T2fat is calculated from the CPMG waveform f(t) by the least squares method or the like. It is known that the transverse relaxation time T2lean takes a value that is clearly different from the transverse relaxation time T2fat (specifically, a value that is two to three times different) near the body temperature of a cow (near 40°C) (see, for example, Non-Patent Document 4). Therefore, even if the muscle of a living livestock that contains fat is scanned with the nuclear magnetic resonance sensor 200, as shown in Fig. 12, by modeling it using Equation (2), it is possible to easily separate signals derived from fat and signals derived from water in the muscle.

[0033] Therefore, as shown in Figure 12, a nuclear magnetic resonance sensor 200 is placed near the body surface of a live livestock to acquire a CPMG waveform f(t). Then, the transverse relaxation time T2fat and other parameters are calculated by fitting equation (2) using the least squares method or the like. Then, the quantitative ratio of the corresponding unsaturated fatty acids is determined from the calibration curve data obtained by the above-mentioned method.

[0034] In addition, when generating a calibration curve, as shown in Figure 12, a nuclear magnetic resonance sensor 200 may be placed near the body surface of a live livestock to acquire a CPMG waveform f(t), and equation (2) may be fitted to calculate the transverse relaxation time T2fat, etc., and the live livestock may be slaughtered and the ratio of unsaturated fatty acids in the fat of its muscle may be measured using another method.

[0035] In this embodiment, the configuration of the nuclear magnetic resonance apparatus is the same as that shown in Fig. 10, and the basic processing flow is also the same as that shown in Fig. 11. As shown in Fig. 12, the magnetic resonance sensor 200 is placed near the body surface of a living livestock, so the difference is that equation (2) is fitted when calculating the transverse relaxation time T2fat. As described above, the calibration curve may be generated according to equation (1) for a portion containing only fat, as in the first embodiment, or according to equation (2) for a portion of muscle containing fat.

[0036] Although the embodiment of the present invention has been described above, the present invention is not limited to this. For example, the functional configuration shown in Fig. 10 is an example, and the functional configuration may be such that the processing described above is performed. Regarding the processing flow, the processing order may be changed or multiple processes may be performed in parallel, as long as the processing results do not change.

[0037] The measuring device 100 described above includes a computer device, and as shown in FIG. 13 , this computer device includes a memory 2501, a CPU (Central Processing Unit) 2503, a hard disk drive (HDD) 2505, a display control unit 2507 connected to a display device 2509, a drive device 2513 for a removable disk 2511, an input device 2515, and a communication control unit 2517 for connecting to a network, all connected via a bus 2519. The HDD may be a storage device such as a solid state drive (SSD). An operating system (OS) and application programs for implementing the processes in the embodiments of the present invention are stored in the HDD 2505 and are read from the HDD 2505 to the memory 2501 when executed by the CPU 2503. The CPU 2503 controls the display control unit 2507, communication control unit 2517, and drive device 2513 according to the processing content of the application program to perform predetermined operations. Furthermore, data during processing is mainly stored in the memory 2501, but may also be stored in the HDD 2505. In an embodiment of the present technology, an application program for performing the above-described processing is stored in a computer-readable removable disk 2511 and distributed, and is installed in the HDD 2505 from the drive device 2513. It may also be installed in the HDD 2505 via a network such as the Internet and a communication control unit 2517. Such a computer device realizes the various functions described above through organic cooperation between hardware such as the CPU 2503 and memory 2501 described above and programs such as the OS and application programs.

[0038] The data used in executing the above-described processing is stored in a storage device such as the memory 2501 or the HDD 2505, regardless of whether it is data in the middle of processing or the result of processing.

[0039] The above-described embodiment can be summarized as follows.

[0040] The measurement system according to this embodiment includes: (A) a nuclear magnetic resonance sensor including a magnetic circuit and a high-frequency coil; and (B) a measurement unit that outputs a predetermined high-frequency pulse to the high-frequency coil, acquires a proton transverse relaxation waveform for a living animal from the high-frequency coil, calculates the transverse relaxation time for fat included in a predetermined model formula by regression analysis of the data on the proton transverse relaxation waveform, and calculates the quantitative ratio of unsaturated fatty acids for the living animal based on the calculated transverse relaxation time for fat and data on a calibration curve prepared in advance.

[0041] Based on the novel and unobvious finding that there is a positive correlation between the ratio of unsaturated fatty acids and the transverse relaxation time of fat, it is now possible to obtain the ratio of unsaturated fatty acids for cattle and other living animals. The ratio of saturated fatty acids is calculated as (100% - total unsaturated fatty acid content ratio).

[0042] When the nuclear magnetic resonance sensor is positioned so that its sensitivity region overlaps with the subcutaneous fat of a living animal, it is preferable to use a model equation consisting of an exponential function representing attenuation and with the transverse relaxation time of fat as the time constant as the predetermined model equation. By positioning the nuclear magnetic resonance sensor slightly away from the body surface of the livestock, it becomes possible to overlap the sensitivity region with the subcutaneous fat of the livestock, and in this case, it becomes possible to appropriately determine the quantitative ratio of unsaturated fatty acids.

[0043] On the other hand, when the nuclear magnetic resonance sensor is positioned so that its sensitivity region overlaps with a portion of a living livestock where fat and muscle are mixed, it is preferable to use a model equation that is the sum of an exponential function that uses the transverse relaxation time of fat as a time constant and represents attenuation, and an exponential function that uses the transverse relaxation time of muscle as a time constant and represents attenuation, as the above-mentioned predetermined model equation. By positioning the nuclear magnetic resonance sensor near the body surface of the livestock, it becomes possible to overlap the sensitivity region with the muscle portion where fat is mixed, and in this case, it becomes possible to appropriately determine the quantitative ratio of unsaturated fatty acids.

[0044] The unsaturated fatty acids mentioned above may include at least one of oleic acid, all unsaturated fatty acids, and monounsaturated fatty acids.

[0045] Furthermore, the computer that executes the measurement method described above may be realized by a single computer or by multiple computers, and these will collectively be referred to as a measurement system or simply a system. [Explanation of symbols]

[0046] 100 Information processing device 200 Nuclear Magnetic Resonance Sensor

Claims

1. a nuclear magnetic resonance sensor including a magnetic circuit and a radio frequency coil; a measuring unit that outputs a predetermined high-frequency pulse to the high-frequency coil, acquires a proton transverse relaxation waveform of a living livestock from the high-frequency coil, calculates a transverse relaxation time of fat included in a predetermined model formula by regression analysis of the data of the proton transverse relaxation waveform, and calculates the quantitative ratio of unsaturated fatty acids of the living livestock based on the calculated transverse relaxation time of fat and data of a calibration curve prepared in advance; and The predetermined model formula is When the nuclear magnetic resonance sensor is disposed so that the sensitivity region of the nuclear magnetic resonance sensor overlaps with the subcutaneous fat portion of the living livestock, A model equation consisting of an exponential function that uses the transverse relaxation time of the fat as a time constant and represents attenuation. Measurement system.

2. a nuclear magnetic resonance sensor including a magnetic circuit and a radio frequency coil; a measuring unit that outputs a predetermined high-frequency pulse to the high-frequency coil, acquires a proton transverse relaxation waveform of a living livestock from the high-frequency coil, calculates a transverse relaxation time of fat included in a predetermined model formula by regression analysis of the data of the proton transverse relaxation waveform, and calculates the quantitative ratio of unsaturated fatty acids of the living livestock based on the calculated transverse relaxation time of fat and data of a calibration curve prepared in advance; and The predetermined model formula is When the nuclear magnetic resonance sensor is disposed so that the sensitivity region of the nuclear magnetic resonance sensor overlaps with a portion of the living livestock where fat and muscle are mixed, A model formula that is the sum of an exponential function that uses the transverse relaxation time of the fat as a time constant and represents attenuation, and an exponential function that uses the transverse relaxation time of the muscle as a time constant and represents attenuation. Measurement system.

3. The unsaturated fatty acids include oleic acid, all unsaturated fatty acids, and / or monounsaturated fatty acids. The measurement system according to claim 1 or 2.

4. a step of outputting a predetermined high-frequency pulse to a high-frequency coil of a nuclear magnetic resonance sensor including a magnetic circuit and a high-frequency coil, and acquiring a proton transverse relaxation waveform of a living livestock from the high-frequency coil; A step of calculating the transverse relaxation time of fat included in a predetermined model formula by regression analysis of the data of the proton transverse relaxation waveform, and calculating the quantitative ratio of unsaturated fatty acids of the living livestock based on the calculated transverse relaxation time of fat and data of a calibration curve prepared in advance; Including, The predetermined model formula is When the nuclear magnetic resonance sensor is disposed so that the sensitivity region of the nuclear magnetic resonance sensor overlaps with the subcutaneous fat portion of the living livestock, A model equation consisting of an exponential function that uses the transverse relaxation time of the fat as a time constant and represents attenuation. Measurement method.

5. a step of outputting a predetermined high-frequency pulse to a high-frequency coil of a nuclear magnetic resonance sensor including a magnetic circuit and a high-frequency coil, and acquiring a proton transverse relaxation waveform of a living livestock from the high-frequency coil; A step of calculating the transverse relaxation time of fat included in a predetermined model formula by regression analysis of the data of the proton transverse relaxation waveform, and calculating the quantitative ratio of unsaturated fatty acids of the living livestock based on the calculated transverse relaxation time of fat and data of a calibration curve prepared in advance; Including, The predetermined model formula is When the nuclear magnetic resonance sensor is disposed so that the sensitivity region of the nuclear magnetic resonance sensor overlaps with a portion of the living livestock where fat and muscle are mixed, A model formula that is the sum of an exponential function that uses the transverse relaxation time of the fat as a time constant and represents attenuation, and an exponential function that uses the transverse relaxation time of the muscle as a time constant and represents attenuation. Measurement method.

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