Method for detecting antioxidant property and method for estimating content of antioxidant substance

Abstract

To provide an antioxidative property detection method capable of performing noninvasive and continuous measurement without requiring a complicated pretreatment process.SOLUTION: An antioxidant property detecting method comprising the steps of: performing near-infrared spectroscopy (680 - 2, 500nm (14706 - 4, 000cm - 1)) on a test object containing water molecules to obtain near-infrared spectra; and determining a value of absorbance at a specific wavelength observed when water molecules coexist with an antioxidant substance in the test object to detect an antioxidant property of the test object based on the value of absorbance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for detecting antioxidant activity and a method for estimating the content of antioxidant substances. [Background technology]

[0002] Redox reactions are fundamental chemical processes that occur at the cellular level. At their core, redox reactions involve the transfer of electrons from one molecule (reducing agent) to another molecule (oxidizing agent), accompanied by a change in molecular structure. Diseases such as cancer, neurodegenerative diseases, and cardiovascular diseases are thought to be associated with an imbalance in redox homeostasis, resulting from oxidative stress resulting from an excess of reactive oxygen species (ROS) and a lack of antioxidant defenses in the body.

[0003] Previously, attempts to measure the redox state in biological systems have been made using biomarkers such as glutathione. Glutathione, an antioxidant tripeptide, exists in a reduced form (GSH) and an oxidized form (GSSG), and attempts have been made to measure the redox state in biological systems by distinguishing between the reduced and oxidized forms of glutathione. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Polovka, M., Brezova, V. and Simko, P. (2007). A tool to characterize the gamma irradiated foods. J. Food Nutr. Res., 46, 75-83 [Non-patent document 2] Journal of the Japanese Society of Nutrition and Food Science, 45(4), 363-365, 1992 Summary of the Invention [Problem to be solved by the invention]

[0005] Measurement of redox status using biomarkers has been performed using a variety of methods, including electron spin resonance (ESR), high-performance liquid chromatography (HPLC), dye-binding assays (Erimans reagents), and fluorescent probes. For example, ESR can specifically detect radicals, and according to Non-Patent Document 1, it is effective for characterizing foods irradiated with gamma rays. This method involves air displacement to eliminate the influence of dissolved oxygen in the solution, solidification of the liquid at low temperatures, and decomposition of radicals due to changes in the measurement environment, all of which affect stability and detection sensitivity. HPLC detection requires pretreatment, such as the addition of perchloric acid to the measurement sample or electrolytic reduction treatment, and complex instrument operation is required for separation and detection (see Non-Patent Document 2). When using fluorescent probes, the solution reaction with the analyte (pretreatment) and degeneration of the fluorescent substance due to excitation light present obstacles to non-staining and continuous measurement. These measurement methods require complex pretreatments such as extraction, purification, and derivatization of biological samples, and are invasive and discontinuous techniques.

[0006] In light of the above-mentioned demands, an object of the present invention is to provide an antioxidant detection method that does not require a complicated pretreatment step and allows non-invasive and continuous measurement. [Means for solving the problem]

[0007] That is, the present invention relates to a method for detecting antioxidant activity. [1] Near-infrared spectrum measurement (680-2,500 nm (14,706-4,000 cm)) for test objects containing water molecules -1 )) to obtain near-infrared light spectrum data; An antioxidant detection method comprising the steps of: determining the absorbance value of a specific wavelength observed when water molecules coexist with an antioxidant substance in the test object from the near-infrared light spectrum data; and detecting the antioxidant properties of the test object based on the absorbance value. [2] The antioxidant detection method described in [1] above, in which the absorbance at the specific wavelength is at least one of absorbance A of a peak near 1381 nm and absorbance B of a peak near 1362 nm, and if the absorbance value of at least one of absorbance A and absorbance B is higher than the reference value established for each absorbance, the test object is determined to have antioxidant properties. [3] The antioxidant detection method according to [1] or [2] above, wherein the test object contains multiple types of antioxidant substances. [4] The antioxidant detection method according to any one of [1] to [3] above, wherein the test object is non-destructively measured using reflected light. [5] The antioxidant detection method according to any one of [1] to [4] above, wherein the test object is a food or drink. [6] The antioxidant detection method according to [5] above, wherein the test object is a beverage. [7] The antioxidant detection method according to [6], wherein the test object is functional water or treated water. [8] The antioxidant detection method according to [5] above, wherein the test object is a supplement or a vitamin preparation. [9] The antioxidant detection method according to [5] above, wherein the test object is an agricultural product.

[10] The antioxidant detection method according to any one of [1] to [4] above, wherein the test object is a pharmaceutical product.

[11] The antioxidant detection method according to any one of [1] to [4] above, wherein the test object is a cosmetic.

[12] The antioxidant detection method according to any one of [1] to [4] above, wherein the test object is a textile product or a resin product.

[13] The antioxidant detection method according to any one of [1] to [4] above, wherein the test subject is a living organism and the antioxidant activity in the living organism at the measurement site is detected.

[0008] The present invention also relates to a method for estimating the content of antioxidants.

[14] Near-infrared spectroscopy (680-2,500 nm (14,706-4,000 cm)) was performed on a standard sample containing water molecules and antioxidants of known content. -1preparing a library in which, in near-infrared spectrum data obtained by performing the above-mentioned steps, absorbance values ​​at specific wavelengths observed when water molecules coexist with antioxidant substances in the standard samples are correlated with the contents of the antioxidant substances; A method for estimating the content of an antioxidant substance, comprising: performing near-infrared spectrum measurement on a test object containing water molecules to obtain near-infrared spectrum data; and estimating the content of the antioxidant substance in the test object by comparing the absorbance value at the specific wavelength in the obtained near-infrared spectrum data with the absorbance value at the specific wavelength in the library.

[0009] What is very important about the present invention is that light is not only used to detect antioxidant activity and measure the content of antioxidant substances, but also as a perturbation (secondary stimulus) to the water molecular system. The researchers interacted with the water molecules in the samples with various wavelengths of light, and then acquired spectra of each sample under successive illumination to record how the water in the samples changed in the presence of the light perturbation. They found a significant band of water molecules whose light absorption was affected by oxidation. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an antioxidant detection method that does not require a complicated pretreatment step and allows non-invasive and continuous measurement. [Brief explanation of the drawings]

[0011] [Figure 1] Figure 1 shows a regression model of near-infrared spectrum charts, which show the near-infrared spectra of an aqueous solution of reduced glutathione and an aqueous solution of oxidized glutathione, respectively, combined into a single figure. [Figure 2] Figure 2 shows a regression model of the near-infrared spectrum chart, which shows the near-infrared spectra of aqueous solutions of NADH and NAD+ measured separately and combined into one figure. [Figure 3A] FIG. 3A is a differential spectrum chart of GSH. [Figure 3B] FIG. 3B is a differential spectrum chart of GSSG. [Figure 4] FIG. 4 is a graph showing the relationship between estimated and measured values ​​of GSH and GSSG contents. [Figure 5A] FIG. 5A is a differential spectrum chart of NADH. [Figure 5B] Figure 5B is a differential spectrum chart of NAD+. DETAILED DESCRIPTION OF THE INVENTION

[0012] The antioxidant detection method of the present invention includes a step of performing near-infrared spectrum measurement on a test object containing water molecules to obtain near-infrared spectrum data; In the near-infrared light spectrum data, the absorbance value of a specific wavelength observed when water molecules coexist with an antioxidant substance in the test object is calculated, and a process is performed to detect the antioxidant properties of the test object based on the absorbance value.

[0013] In the antioxidant detection method of the present invention, near-infrared spectrum measurement is performed on a test object containing water molecules to obtain near-infrared spectrum data. Near-infrared light spectrum measurement is performed at wavelengths of 680-2,500 nm (14,706-4,000 cm -1 ) onto the object being inspected. Since light of specific wavelengths is absorbed depending on the type and condition of the object being inspected, the type and condition of the object can be determined by plotting wavelength on one axis (horizontal axis) and absorbance on the other axis (vertical axis).

[0014] If the wavelength of light of interest is already determined, it is not necessary to irradiate the entire wavelength range of 680-2,500 nm, and it is possible to irradiate only light of the specific wavelength of interest. In this case, the measurement device can be made smaller. That is, in the present invention, near-infrared spectrum measurement is performed in the wavelength range of 680-2,500 nm (14,706-4,000 cm -1It is not essential to measure the entire range of

[0015] In the present invention, near-infrared spectrum measurement is performed on an object to be inspected that contains water molecules. Water molecules exhibit absorption peaks at different positions depending on their state in the object to be inspected. Specifically, absorption peaks may be due to interactions with substances other than water molecules contained in the object to be inspected, absorption peaks due to clusters of water molecules, or absorption peaks due to free water that does not interact with other molecules.

[0016] In the present invention, the absorbance value at a specific wavelength observed when water molecules coexist with an antioxidant in the test object is determined from near-infrared spectrum data. When water molecules coexist with an antioxidant in the test object, the peak at the specific wavelength becomes higher or lower compared to when water molecules do not coexist with an antioxidant. In addition to the case where the peak at a specific wavelength becomes higher, the case where the peak at a specific wavelength becomes lower also falls under the term "determining the absorbance value at a specific wavelength observed when water molecules coexist with an antioxidant" in the present invention.

[0017] Near-infrared spectral data when water molecules coexist with an antioxidant will be explained using the example of reduced glutathione (GSH) as the antioxidant.

[0018] Glutathione is a substance that serves as an indicator of neurological diseases and dementia, and exists as reduced glutathione (GSH) and oxidized glutathione (GSSG). The reduced glutathione shown in the chemical formula above has a structure with an -SH group, and the oxidized glutathione shown below has a structure in which two molecules of reduced glutathione are bonded together with the SH group replaced by an SS group. (Structural formula of reduced glutathione) [ka] (Structural formula of oxidized glutathione (two molecules bonded)) [ka]

[0019] Figure 1 shows a regression model of near-infrared spectrum charts, which show the near-infrared spectra of an aqueous solution of reduced glutathione and an aqueous solution of oxidized glutathione, respectively, combined into a single figure. The chart for reduced glutathione shows two peaks at 1362 nm and 1381 nm, and has a higher absorbance than oxidized glutathione.

[0020] The peaks at 1362 nm and 1381 nm, which have high absorbance values, are peaks derived from water molecules that coexist with reduced glutathione. The state of water molecules that produces these peaks is discussed below.

[0021] Water molecules are thought to form clusters around the -SH groups of reduced glutathione, which correspond to the two peaks at 1362 nm and 1381 nm in the chart of an aqueous solution of reduced glutathione. The presence of two peaks at 1362 nm and 1381 nm in the chart of an aqueous solution of reduced glutathione indicates the presence of water molecules coexisting with reduced glutathione. In other words, the presence of two peaks at 1362 nm and 1381 nm can be said to confirm the presence of reduced glutathione.

[0022] Unlike reduced glutathione, oxidized glutathione does not have -SH groups, making it difficult for water molecules to form clusters. As a result, depending on the oxidized glutathione, the two peaks at 1362 nm and 1381 nm may not be observed, or even if they are observed, their heights may be low.

[0023] In near-infrared light spectrum data, by determining the absorbance value at specific wavelengths (1362 nm and 1381 nm in the above example) observed when water molecules coexist with reduced glutathione in the test object, the presence of reduced glutathione in the test object can be detected based on the absorbance value. Reduced glutathione is an antioxidant, so by detecting the presence of reduced glutathione, the antioxidant properties of the test object can be detected.

[0024] The peak at a specific wavelength observed when water molecules coexist with an antioxidant is observed at approximately the same position even for antioxidants other than reduced glutathione. Below, a case where the antioxidant is NADH will be described as another antioxidant. NAD (nicotinamide adenine dinucleotide) NAD + +2H + +2e - NADH+H + NAD is a substance that undergoes an oxidation-reduction reaction. + is the oxidized form and NADH is the reduced form.

[0025] Figure 2 shows the relationship between NADH and NAD + The near-infrared spectrum of each of the aqueous solutions was measured and combined into a single chart, which is a regression model of the near-infrared spectrum chart. In this chart, just as in the case where the antioxidant was reduced glutathione (Figure 1), the chart for the antioxidant NADH shows two peaks at 1365 nm and 1383 nm, indicating that NAD + The absorbance is higher than

[0026] Therefore, the peak at a specific wavelength observed when water molecules coexist with an antioxidant substance does not depend on the type of antioxidant substance, and the antioxidant properties of the test object can be detected by focusing on the peak at the same specific wavelength.

[0027] Furthermore, although the above describes an example in which two forms, reduced and oxidized, exist and the reduced form is the antioxidant substance, the present invention may also be applied to antioxidant substances that do not take two forms, reduced and oxidized.

[0028] In addition to the reduced glutathione and NADH mentioned above, examples of antioxidant substances include carotenoids (lycopene, astaxanthin, beta-carotene, etc.), polyphenols (flavonoids, catechin, chlorogenic acid, anthocyanin, quercetin, resveratrol, curcumin, and their glycosides, etc.), vitamins (vitamin A, vitamin C, vitamin E, carnitine), amino acids (glycine, cysteine), selenium, fulvic acid, coenzyme Q10, phytosterols, omega-3 fatty acids, etc.

[0029] In the antioxidant detection method of the present invention, the test object may contain multiple types of antioxidant substances.

[0030] In the antioxidant detection method of the present invention, if the absorbance at the specific wavelength is at least one of absorbance A with a peak around 1381 nm and absorbance B with a peak around 1362 nm, and the absorbance value of at least one of absorbance A and absorbance B is higher than a reference value established for each absorbance, the test object may be determined to have antioxidant properties.

[0031] In the example where the antioxidant is reduced glutathione, we explained that when water molecules coexist with the antioxidant, there are two peaks at 1362 nm and 1381 nm, but in actual measurements the wavelengths may differ slightly. Therefore, the absorbance A value of the peak around 1381 nm (1380-1390 nm) corresponding to the 1381 nm peak, starting from the longest wavelength, and the absorbance B value of the peak around 1362 nm (1360-1375 nm) corresponding to 1362 nm are calculated, and if at least one of the absorbance A and absorbance B values ​​is higher than the standard value established for each absorbance, the test object can be determined to have antioxidant properties. Note that if two peaks appear between 1375 and 1380 nm, the absorbance of the longer wavelength peak can be treated as absorbance A and the absorbance of the shorter wavelength peak can be treated as absorbance B.

[0032] The "standard value established for each absorbance" can be determined in advance by relating the absorbance value at a specific wavelength observed when water molecules coexist with an antioxidant in a standard sample to the content of the antioxidant in near-infrared spectrum data obtained by performing near-infrared spectrum measurement on a standard sample containing water molecules and a known content of an antioxidant.

[0033] Furthermore, if the near-infrared spectrum measuring device is a measuring device that measures the absorbance of the peak on the short wavelength side, it can be made smaller than a measuring device that measures the absorbance on the long wavelength side, so the device configuration can be simplified.

[0034] When using absorbance values ​​(numerical values) in comparison with a reference value, the near-infrared light spectrum data can be subjected to a predetermined statistical analysis or conversion process to quantify the absorbance of a specific wavelength in the near-infrared light spectrum data, and then compared with the reference value corresponding to that condition. The statistical analysis method and the conversion processing method are not particularly limited, but can be performed by combining techniques such as subtracting the spectra of other known components contained in the spectral data (difference spectrum processing), principal component analysis, multiple regression analysis, and regression processing using the least squares method.

[0035] The width of "near" such as around 1381 nm is roughly the following range: As an example, absorbance A corresponds to 1380 nm or more and 1390 nm or less, and absorbance B corresponds to 1360 nm or more and less than 1375 nm.

[0036] The near-infrared spectroscopic device used in the antioxidant detection method of the present invention may be a device that irradiates only light of a specific wavelength. Examples include a device that irradiates only light of wavelengths equal to or greater than 1380 nm and equal to or less than 1390 nm and wavelengths corresponding to its overtones in order to obtain a value of absorbance A, and a device that irradiates only light of wavelengths equal to or greater than 1360 nm and equal to or less than 1375 nm and wavelengths corresponding to its overtones in order to obtain a value of absorbance B. A device that irradiates only light of a specific wavelength and wavelengths corresponding to its overtones has a simple structure and can be made smaller.

[0037] Furthermore, when measuring a test object that contains a substance that exists in both its reduced and oxidized forms, such as glutathione, which is an antioxidant substance, measurements may be performed focusing only on the reduced form, or measurements may also be performed focusing on the oxidized form. In the case of glutathione, even if reduced glutathione and oxidized glutathione coexist in the test subject, the ratio of reduced glutathione to oxidized glutathione changes little over time, and the ratio is maintained based on the ratio at the time of mixing. It is thought that the proportion of oxidized forms increases gradually due to the influence of oxygen in the air.

[0038] The antioxidant detection method of the present invention can be carried out by measuring the near-infrared spectrum of a measurement object, and is a non-invasive method that does not require the measurement object to be destroyed. Furthermore, it is not necessary to administer any substance to the measurement object for staining or the like. Furthermore, a reflection-type near-infrared spectrometer that uses reflected light can be used as a device for performing non-invasive and non-destructive measurements.

[0039] The antioxidant detection method of the present invention can be applied to test objects such as food and beverages. Among food and beverages, beverages are preferred, and the antioxidant properties of components contained in beverages can be evaluated. The type of beverage is not particularly limited, and may include tea beverages, coffee beverages, alcoholic beverages, functional beverages, sports drinks, carbonated beverages, fruit juice beverages, fruit and vegetable beverages, dairy beverages, soy milk beverages, flavored water, and the like.

[0040] The test object may be functional water or treated water, which is water that has been labeled as having been treated by a specific method, such as an electromagnetic field or electrochemical reduction, and includes water that is said to have antioxidant properties.

[0041] The test object may be a supplement or a vitamin preparation, some of which contain substances with antioxidant properties.

[0042] Furthermore, agricultural products are preferred as food products, and the antioxidant properties of components contained in agricultural products can be evaluated. The types of agricultural products are not particularly limited, but examples include vegetables and fruits, such as green and yellow vegetables as tomatoes, spinach, bell peppers, paprika, carrots, and broccoli. Because the test can be performed non-invasively, it can be used to inspect agricultural products before they are shipped or immediately before cooking.

[0043] The test object may be a medicine, including medicines that are taken orally, medicines that are taken by other means, and medicines for external use.

[0044] The object to be inspected may be a cosmetic product.

[0045] The object to be inspected may be a textile or resin product, such as a polymer or coating, that may have antibacterial or antioxidant properties, such as wound dressings or other biomaterials.

[0046] Furthermore, if the test subject is a living organism, it is possible to detect antioxidant activity in the organism at the measurement site. Since it can be performed non-invasively, it places little strain on the organism. For example, it can be used to detect reduced glutathione in the brain of a living organism. It has been pointed out that the presence of reduced glutathione in the brain may be related to the improvement of symptoms of schizophrenia and Alzheimer's disease, so detecting reduced glutathione in the organism is significant. Measurements can also be performed using samples of any bodily fluid, such as saliva, blood, or urine. It is anticipated that medicines, supplements, cosmetics, and other substances that may be contained in these samples will also be tested. The living body to be inspected may be any body other than a human.

[0047] The method for estimating the content of antioxidants according to the present invention will be described below. In the method for estimating the content of antioxidants of the present invention, a standard sample containing water molecules and antioxidants of known content is subjected to near-infrared spectroscopy (680-2,500 nm (14,706-4,000 cm)). -1 )) is used to obtain near-infrared spectrum data. A library is prepared in which the absorbance value at a specific wavelength observed when water molecules coexist with an antioxidant in the standard sample is correlated with the content of the antioxidant.

[0048] The absorbance value at a specific wavelength observed in near-infrared spectrum data obtained by performing near-infrared spectrum measurement on a sample containing water molecules and antioxidants is related to the concentration of the antioxidants, and when the concentration of the antioxidants is high, the absorbance value at the specific wavelength becomes high (or low). Therefore, a library can be created by using standard samples with known concentrations of antioxidants and recording the absorbance values ​​at specific wavelengths in relation to the antioxidant content.

[0049] Then, near-infrared spectrum measurement is performed on a test object containing water molecules and whose antioxidant content is unknown, to obtain near-infrared spectrum data, and the absorbance value at a specific wavelength in the obtained near-infrared spectrum data is compared with the absorbance value at the specific wavelength in the library, thereby making it possible to estimate the content of the antioxidant in the test object.

[0050] Specific embodiments of the method of estimating the content of an antioxidant substance of the present invention can be similar to the specific embodiments of the method of detecting antioxidant activity of the present invention. When multiple absorbance values, such as absorbance A and absorbance B, are used as absorbance values ​​at specific wavelengths, the library also records the correlation between the multiple absorbances and the antioxidant contents. Any predetermined statistical analysis or conversion process can be used to correlate the multiple absorbances and the antioxidant contents. [Example]

[0051] Hereinafter, examples of the method for detecting antioxidant activity and the method for estimating the content of antioxidant substances according to the present invention will be described, although the present invention is not limited to the following examples.

[0052] (sample) Reduced glutathione (GSH) (Fujifilm Wako Pure Chemical Industries, Ltd.) and oxidized glutathione (GSSG) (Fujifilm Wako Pure Chemical Industries, Ltd.) were prepared in phosphate-buffered saline (PBS) at concentrations ranging from 1 to 10 mM in 1 mM increments (1 mM to 10 mM). The pH was adjusted to 7.5 with 5 M NaOH.

[0053] Reduced nicotinamide adenine dinucleotide (β-NADH) (Fujifilm Wako Pure Chemical Industries, Ltd.) and oxidized nicotinamide adenine dinucleotide (β-NAD) prepared in PBS were used. + ) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was prepared. In the explanation of the examples, β-NADH, β-NAD + NADH and NAD + It is written as follows.

[0054] (near-infrared spectrum measurement) NIRS detection: NIR transmission spectra were acquired using FT-NIR spectroscopy (Bruker, MPA, resolution: 8 cm -1 (64 scans, 1 mm path length sample cell was used.) For each sample, 64 scans were measured 25 times, resulting in 1,600 spectra.

[0055] (Data Analysis) All multivariate analyses were performed using the software Pirouette ver. 4.5 (Informetrix) and MATLAB (registered trademark) (version 7.1; The MathWorks). Before multivariate analysis of the spectra from 1100-1850 nm and 2050-2400 nm or 1300-1600 nm, the region from 1850-2050 nm was excluded because high absorption spectra above the measurement limit were observed in the region.

[0056] (Pretreatment) Baseline-corrected difference spectra were obtained by smoothing using standard normalization (SNV). Noise was reduced by smoothing using a Savitzky-Golay filter (smooth(25)) between 1100 and 2400 nm (excluding 1850 and 2050 nm). Furthermore, the similarity of each spectrum was expressed using the Mahalanobis distance of principal component analysis (PCA), and data with singular values ​​were removed as outliers.

[0057] (Analysis by differential spectrum) The difference spectrum method was used to highlight small variations due to changes in the concentrations of GSH and GSSG that are buried in the large peak of the water spectrum.

[0058] (Measurement results) Figure 3A is a differential spectrum chart of GSH, and Figure 3B is a differential spectrum chart of GSSG. Ten spectra are shown, each with a concentration ranging from 1 mM to 10 mM, with the darker the line, the higher the concentration. From this differential spectrum chart, it was clear that there was a specific peak in the wavelength range of 1300 to 1600 nm that allowed GSH and GSSG to be distinguished. Two peaks specific to GSH were present at around 1362 nm and 1381 nm, but such peaks were not present in GSSG.

[0059] FIG. 4 is a graph showing the relationship between estimated and measured values ​​of GSH and GSSG contents. The difference spectra were standardized and smoothed by preprocessing as data for the prediction model. Outliers were removed using Mahalanobis distance on PCA, and partial least squares regression (PLSR) was applied to the difference spectra to predict GSH and GSSG concentrations. The horizontal axis shows the measured values ​​of GSH and GSSG contents, and the vertical axis shows the estimated values ​​of GSH and GSSG contents. The estimated values ​​of GSH and GSSG contents shown on the vertical axis are estimated values ​​calculated using the method of estimating the content of antioxidant substances of the present invention. The estimated values ​​and the measured values ​​showed good correlation, with a correlation coefficient of 0.98 and a root mean square error (RMSE) of 0.40 for GSH and 0.99 and 0.23 for GSSG, respectively. Figure 1 shows a regression model for predicting concentrations of GSH and GSSG obtained by applying partial least squares regression (PLSR) to the difference spectra for predicting concentrations of GSH and GSSG.

[0060] In addition, NADH and NAD were measured in the same manner as for GSH and GSSG. + Measurements were carried out to obtain the charts shown in FIGS. 5A and 5B. Figure 5A is a differential spectrum chart of NADH, and Figure 5B is a differential spectrum chart of NAD + This is a differential spectrum chart of NADH and NAD in the wavelength range of 1300-1600 nm. Ten spectra with concentrations varying by 1 mM each are shown together, with the darker the line the higher the concentration. + It was clear that there were specific peaks that could be identified. There are two peaks specific to NADH at around 1365 nm and 1383 nm. + did not exist in. In addition, Figure 2 shows the relationship between NADH and NAD as well as GSH and GSSG. +This is a regression model for concentration prediction obtained by applying partial least squares regression (PLSR) to the difference spectrum for concentration prediction. [Industrial Applicability]

[0061] According to the present invention, it is possible to provide an antioxidant detection method that does not require a complicated pretreatment step and allows non-invasive and continuous measurement.

Claims

1. Near-infrared spectrum measurement (680-2,500 nm (14,706-4,000 cm)) of the test object containing water molecules －１ )) to obtain near-infrared light spectrum data; An antioxidant detection method comprising the steps of: determining an absorbance value at a specific wavelength observed when water molecules coexist with an antioxidant substance in the test object from the near-infrared light spectrum data; and detecting the antioxidant properties of the test object based on the absorbance value.

2. 2. The antioxidant detection method according to claim 1, wherein the absorbance at the specific wavelength is at least one of an absorbance A having a peak near 1381 nm and an absorbance B having a peak near 1362 nm, and the object to be tested is determined to have antioxidant properties if the absorbance value of at least one of the absorbance A and the absorbance B is higher than a reference value established for each absorbance.

3. 2. The antioxidant detection method according to claim 1, wherein the test object contains a plurality of types of antioxidant substances.

4. 2. The antioxidant detection method according to claim 1, wherein the test object is non-destructively measured using reflected light.

5. The antioxidant detection method according to claim 1, wherein the test object is a food or drink.

6. The antioxidant detection method according to claim 5, wherein the test object is a beverage.

7. The antioxidant detection method according to claim 6, wherein the test object is functional water or treated water.

8. The antioxidant detection method according to claim 5, wherein the test object is a supplement or a vitamin preparation.

9. The antioxidant detection method according to claim 5, wherein the test object is an agricultural product.

10. The antioxidant detection method according to claim 1, wherein the test object is a pharmaceutical product.

11. The antioxidant detection method according to claim 1, wherein the test object is a cosmetic.

12. The antioxidant detection method according to claim 1, wherein the test object is a textile product or a resin product.

13. 2. The antioxidant detection method according to claim 1, wherein the test object is a living organism, and the antioxidant activity in the living organism at a measurement site is detected.

14. Near-infrared spectroscopy (680-2,500 nm (14,706-4,000 cm)) was performed on a standard sample containing water molecules and antioxidants of known content. －１ preparing a library in which absorbance values ​​at specific wavelengths observed when water molecules coexist with antioxidant substances in the standard samples are correlated with the contents of the antioxidant substances in near-infrared spectrum data obtained by performing the above-mentioned step (1); A method for estimating the content of antioxidants in a test object containing water molecules, comprising: performing near-infrared spectrum measurement on the test object to obtain near-infrared spectrum data; and estimating the content of antioxidants in the test object by comparing the absorbance value at the specific wavelength in the obtained near-infrared spectrum data with the absorbance value at the specific wavelength in the library.

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