JP2021185876A - Laver quality evaluation method and laver quality evaluation device - Google Patents

Abstract

To provide a method for evaluating in non destructive manner, quality of laver.SOLUTION: There is provided a laver quality evaluation method comprises: a step (step S11) for radiating excitation light to laver; a step (step S21, 22) for detecting Raman scattering light of the laver with respect to the excitation light, detecting first Raman scattering light detected in a wave number area selected from 500 cm-1 to 1700 cm-1, and second Raman scattering light detected in a wave number area selected from 2500 cm-1 to 3300 cm-1; a step (step S31) for calculating a Raman scattering light relative strength ratio related to a strength ratio between the first Raman scattering light and the second Raman scattering light; and a step (step S41) for evaluating quality of the laver, on the basis of the Raman scattering light relative strength ratio.SELECTED DRAWING: Figure 2

Description

The present invention relates to a nori quality evaluation method and a nori quality evaluation device.

Currently, about 7 billion pieces of dried seaweed are produced in Japan in one year. The produced dried seaweed is collected at the bases in each production area, graded by quality evaluation by inspectors, and then distributed from wholesalers to retailers and consumers through bidding. The quality of seaweed, which is a natural product, varies, and it is necessary to adopt non-destructive analysis technology that enables rapid inspection in order to evaluate the quality of a large amount and variety of seaweed.

Currently, the quality of seaweed is evaluated by a sensory test that visually evaluates the color and luster of seaweed, and is classified into about 10 grades. However, in the sensory test based on visual inspection, the evaluation criteria are ambiguous, and there are problems that the judgment result differs depending on the inspector, and the judgment result differs depending on the inspection time even for the same inspector. In addition, the evaluation criteria used in the sensory test differ depending on the production area of seaweed and the country of production (Japan, South Korea, China), and there is currently no objective evaluation standard. Furthermore, the sensory test is an evaluation based on the visual judgment of the inspector, and it is also a problem that the relationship with the evaluation based on the taste and nutritional value, which is originally the most important for food, is not clear.

It is known that the main component of the taste of seaweed is amino acids, and the amount of free amino acids is proportional to the amount of protein contained in seaweed. The protein content is actually used as an index for quality evaluation of seaweed, and the protein content is estimated from near-infrared spectroscopy (absorption spectrum in the near-infrared region). However, in near-infrared spectroscopy, it is necessary to correct the influence of the density of the sample seaweed and the contained water, and there is a problem in measurement accuracy. Furthermore, since it takes time to measure, it cannot be used as a rapid inspection means instead of the sensory test. Therefore, it is necessary to develop a method that can measure the amount of protein contained in seaweed using non-destructive analysis technology that enables rapid measurement.

Patent Document 1 nondestructively detects the amount of photosynthetic pigment of seaweed after it is roasted by the heating device in a roasted seaweed manufacturing device that roasts seaweed by passing it through a heating device by a transfer device. A roasting control device for controlling the heating conditions of the heating device and the transfer conditions of the transfer device so that the reduction rate of the photosynthetic dye calculated from the detection value by the detection device falls within a predetermined range is provided. It relates to a grilled seaweed production apparatus characterized by the above. Here, the transmitted light having a wavelength of 820 nm and a wavelength of 675 nm is measured, and the amount of chlorophyll is determined by comparing with a standard value.

Patent Document 2 describes the wavelength dependence and wavelength of the nori seaweed and / or the aqueous solution in which the water-soluble substance of the nori seaweed is dissolved in the seaweed mixed solution obtained by mixing the seaweed raw algae and water in the process of manufacturing the seaweed product. The present invention relates to a seaweed product quality control device that determines the quality of a seaweed mixed solution and controls the seaweed product manufacturing conditions based on the amount of transmitted light measured by a plurality of light sources having different regions.

Patent Document 3 relates to a seaweed quality evaluation method characterized in that the quality of seaweed is evaluated by irradiating the seaweed with light and analyzing the Raman scattered light generated from the light.

Japanese Unexamined Patent Publication No. 63-9950 Japanese Unexamined Patent Publication No. 2007-89424 Japanese Unexamined Patent Publication No. 2019-154405

Nori contains a plurality of pigments having different absorption wavelengths and has a black color. Those with a darker black color are positioned as higher grade seaweed. Generally, the grade of seaweed is evaluated by a visual sensory evaluation by an inspector. However, the sensory test has the following problems. First, since the sensory test is based on the visual inspection of the inspector, there is no objective evaluation standard. In addition, since there is no proportional relationship between the degree of darkness of seaweed and the content of chromoprotein, it is not possible to accurately distinguish and evaluate high-grade seaweed.

Patent Document 1 measures transmitted light having a wavelength of 820 nm and a wavelength of 675 nm. However, when the degree of blackness based on the light transmittance is evaluated as a function of the concentration of the pigment contained in the seaweed, the amount of change in the degree of blackness becomes small in the region where the chromoprotein content is large due to the relationship between the absorbance and the transmittance. , Accurate evaluation becomes difficult.

Patent Document 2 evaluates the seaweed raw algae and / or the water-soluble substance of the seaweed raw algae in the seaweed mixed solution obtained by mixing the seaweed raw algae and water in the seaweed product manufacturing process as an aqueous solution dissolved. , It is a destructive inspection because it is mixed with water and sampled and evaluated. In addition, since the sample in the intermediate process of dry seaweed production is targeted for evaluation, the quality of the product itself cannot be evaluated.

Patent Document 3 evaluates the quality of seaweed by irradiating the seaweed with light and analyzing the Raman scattered light generated from the light. With this method, dried seaweed can be evaluated non-destructively. However, although this method can measure the amount (content) of the photosynthetic pigment contained in the seaweed, it cannot measure the content of the photosynthetic pigment. If the quality is the same, the content is always the same, but the higher the density of the seaweed and the thicker the seaweed, the larger the value, which becomes a problem when used as an index for quality evaluation. There are variations in the thickness and density of dried seaweed, which is a natural product, but it is necessary to suppress the effects of such variations in thickness and evaluate the quality.

Under such circumstances, it is an object of the present invention to provide a method and an apparatus for nondestructively evaluating the quality of seaweed.

As a result of diligent research to solve the above problems, the present inventor has found that the following invention meets the above object, and has arrived at the present invention. That is, the present invention relates to the following invention.

<1> laver, irradiating the excitation light, it is used to detect the Raman scattered light to the excitation light of the seaweed, is detected in the wave number region selected from the range of 500cm ^-1 ~1700cm ^-1 The step of detecting the first Raman scattered light and the second Raman scattered light detected in the wave number region selected from the range of ^{2500 cm -1 to} 3300 cm ^{-1, and the first Raman scattered light and the first Raman scattered light.} A method for evaluating the quality of seaweed, which comprises a step of calculating the relative intensity ratio of Raman scattered light with respect to the intensity ratio of the second Raman scattered light and a step of evaluating the quality of the seaweed based on the relative intensity ratio of the Raman scattered light. ..
<2> The method for evaluating the quality of seaweed according to <1>, wherein the excitation light is near-infrared light having a peak in a wavelength region selected from the wavelength range of 800 to 1200 nm.
<3> As the first Raman scattered ^{light, 1638cm -1, 1526cm -1, 1158cm} -1, and the wave number difference of 5 cm ^-1 or less with one or more wave number selected from the group consisting of 1007Cm ^-1 The wave number region as a peak is detected, and as the second Raman scattered light, the wave number region having a peak wave number with a difference of 5 cm ^{-1 or less from the wave number of 2933 m -1 is detected.} Alternatively, the method for evaluating the quality of seaweed according to <2>.
<4> the Nori, irradiating means for irradiating excitation light, is used to detect the Raman scattered light to the excitation light of the seaweed, is detected by the wave number region selected from the range of 500cm ^-1 ~1700cm ^-1 The first Raman scattered light and the second Raman scattered light detected in the wave number region selected from the range of ^{2500 cm -1 to} 3300 cm ^{-1 and the first Raman scattered light.} Seaweed having a calculation means for calculating the Raman scattered light relative intensity ratio with respect to the second Raman scattered light intensity ratio and an evaluation means for evaluating the quality of the seaweed based on the Raman scattered light relative intensity ratio. Quality evaluation device.

According to the present invention, the quality of seaweed can be evaluated non-destructively.

It is a schematic diagram of the Embodiment which concerns on the quality evaluation apparatus of this invention. It is a flow chart which shows an example of the quality evaluation method of this invention. It is a figure which shows the Raman spectrum at the different measurement points of dry seaweed. It is a figure which shows the Raman scattered light intensity (◯) of phycocyanin and a carotenoid at five measurement points, and the Raman scattered light relative intensity ratio (●). It is a Raman spectrum of dried seaweed. (A) is high-grade seaweed and (b) is low-grade seaweed. It is a figure which shows the correlation of the photosynthetic dye (phycocyanin and carotenoid) content determined from the extraction experiment, and the content estimated from the Raman spectrum. Raman spectrum of dry seaweed and water. (A) is dried seaweed and (b) is water.

Hereinafter, embodiments of the present invention will be described in detail, but the description of the constituent elements described below is an example (representative example) of the embodiments of the present invention, and the present invention is described below unless the gist thereof is changed. It is not limited to the contents of. In addition, when the expression "~" is used in this specification, it is used as an expression including numerical values before and after it.

[Quality Evaluation Method of the Present Invention]
Quality evaluation method of the present invention, the seaweed, irradiating the excitation light, is used to detect the Raman scattered light to the excitation light of the seaweed, wave number selected from the range of 500cm ^-1 ~1700cm ^-1 The step of detecting the first Raman scattered light detected in the region and the second Raman scattered light detected in the wave number region selected from the range of ^{2500 cm -1 to} 3300 cm ^{-1, and the first Raman.} It has a step of calculating the Raman scattered light relative intensity ratio regarding the intensity ratio of the scattered light and the second Raman scattered light, and a step of evaluating the quality of the seaweed based on the Raman scattered light relative intensity ratio. .. According to the quality evaluation method of the present invention, the quality of seaweed can be evaluated non-destructively.

[Quality Evaluation Device of the Present Invention]
Quality evaluation apparatus of the present invention, the seaweed, and irradiating means for irradiating excitation light, is used to detect the Raman scattered light to the excitation light of the seaweed is selected from the range of 500cm ^-1 ~1700cm ^-1 The detection means for detecting the first Raman scattered light detected in the wave number region and the second Raman scattered light detected in the wave number region selected from the range of ^{2500 cm -1 to} 3300 cm ^{-1 and the first.} A calculation means for calculating the Raman scattered light relative intensity ratio regarding the intensity ratio of the Raman scattered light and the second Raman scattered light, and an evaluation means for evaluating the quality of the seaweed based on the Raman scattered light relative intensity ratio. And have. According to the quality evaluation device of the present invention, the quality of seaweed can be evaluated non-destructively.

In the present application, the quality evaluation method of the present invention can be performed by the quality evaluation device of the present invention, and the configurations corresponding to the respective can be mutually used in the present application.

The present invention simultaneously observes and uses the spectrum of the low wave number region in which Raman scattered light derived from a photosynthetic dye is observed and the spectrum of the high wave number region in which signals derived from proteins and carbohydrates are observed. Thereby, the content rate (that is, the concentration) of the photosynthetic pigment can be obtained without being affected by the difference in the density and thickness of the seaweed. Moreover, since the influence of water on the Raman spectrum of seaweed can be ignored, it is not necessary to correct the water content and humidity contained in the sample, and stable and accurate quantitative analysis is possible.

[First Embodiment of the quality evaluation device of the present invention]
FIG. 1 is a schematic diagram of a first embodiment according to the quality evaluation device of the present invention. The quality evaluation device 100 is a device for evaluating the quality of the seaweed 2. The quality evaluation device 100 has a configuration corresponding to the excitation light irradiation means, the detection means, the calculation means, and the evaluation means in the quality evaluation device of the present invention.

As the excitation means for irradiating the excitation light, the laser light source 11 and the photometric system 31 are provided. As means for detecting Raman scattered light, it has a photometric system 31, an optical fiber 32, a spectroscope 33, a detector 34, and a detection unit 4. A calculation unit 51 is provided as a calculation means for calculating the Raman scattered light relative intensity ratio. The evaluation unit 61 is provided as an evaluation means for evaluating the quality of seaweed. Further, it has a storage unit 7 for storing the detected and calculated data, data used for control, and the like, and a monitor 8 for displaying the data and the like.

[Flow diagram of quality evaluation of the present invention]
FIG. 2 is a flow chart showing an example of the quality evaluation method of the present invention. This quality evaluation method can also be performed using the quality evaluation device 100.

[Irradiation (step S11)]
Step S11 is a step of irradiating the seaweed as a sample with excitation light. In the quality evaluation device 100, the seaweed 2 is installed as a sample on the sample table, and the light of the laser 11 is used as the excitation light, and the optical path, the amount of light, and the like are adjusted so as to hit the seaweed 2 in the photometric system 31 and irradiated. Will be done.

The seaweed can be evaluated in any manner such as dried seaweed, raw seaweed, and a state in which seaweed is dispersed in water or the like. The inspection device and inspection method of the present invention are non-destructive and can be evaluated while suppressing variations in thickness and density, and are therefore particularly suitable for evaluation of dried seaweed.

The excitation light is incident light for obtaining Raman scattered light of seaweed. The excitation light is preferably near-infrared light having a peak in a wavelength region selected from the wavelength range of 800 to 1200 nm. Irradiation of light of such a wavelength has very little effect on the quality of seaweed due to irradiation of light. In addition, it is easy to detect Raman scattered light even in black seaweed. Further, the excitation light is preferably light from a laser light source. Since Raman scattered light has low intensity, it is suitable to use laser light as excitation light for stable detection.

[Detection (step S21, step S22)]
Step 21 and step S22 are steps of detecting Raman scattered light from the seaweed irradiated with the excitation light in step S21. In the quality evaluation device 100, the Raman scattered light scattered from the seaweed 2 is incident on the photometric system 31, guided to the spectroscope 33 by the optical fiber 32, and the light dispersed by the spectroscope 33 is detected as the Raman spectrum by the detector 34. do. From this Raman spectrum, the Raman scattered light intensity for evaluating the quality of seaweed is detected by the detection unit 4. In the detection unit 4, the first Raman scattered light is detected by the first detection unit 41. Further, the second Raman scattered light is detected by the second detection unit.

Step S21 is a step of detecting a first Raman scattered light detected by the wave number region selected from the range of 500cm ^-1 ~1700cm ^-1. Step S22 is a step of detecting the second Raman scattered light detected in the wave number region selected from the range of ^{2500 cm -1 to} 3300 cm ^-1.

In detecting the first Raman scattered light and the second Raman scattered light, first, the Raman spectrum in a wide wave number region is acquired, and the Raman scattered light intensity in the corresponding wave number region is detected from the Raman spectrum. be able to.

The first Raman scattered light relates to a wavenumber region in which Raman scattered light derived from a photosynthetic dye is observed. The first detection of Raman scattered light can be detected as an integrated value of the peak intensity of Raman scattered light corresponding to such a photosynthetic dye and the scattered light intensity in a predetermined range. Range for detecting the first Raman scattered light may be in the range of 900 cm ^-1 1650 cm ^-1. Further, it may be limited by the wave number region corresponding to the peak.

In the range of the first Raman scattered light, for example, Raman scattered light corresponding to phycocyanin is obtained from the band ^{having a peak of 1638 cm-1.} In addition, Raman scattered light mainly attributed to carotenoids can be obtained from sharp bands with peaks of 1550 cm ^-1 or less (1526 cm ^-1 , 1158 cm ^-1 , 1007 cm ^-1). The first Raman scattered light may be detected or a plurality of may be detected only in the range corresponding to one or more of these peaks.

Focusing on this phycocyanin and carotenoids, as a first Raman scattered ^{light, 1638cm -1, 1526cm -1, 1158cm} -1, and the difference between the one or more wave number selected from the group consisting of 1007cm ^-1 is 5 cm ^-1 It is preferable to detect a wave number region having a peak of the following wave numbers. The spectrum observed by Raman spectroscopy is relatively narrow, and ^{the accuracy of the wave number (cm -1} ) may vary, and the wave number may vary depending on the measuring device or the like. Therefore, the wave number of the foregoing, are exemplary, for example, for the peak of 1638 cm ^-1, there is a possibility that a peak is observed at around 1638 cm ^-1 can be used as equivalent.

Therefore, in consideration of these variations, ^{a wave number having a peak difference of 5 cm -1} or less (that is, ± 5 cm ^-1 ) from the above-mentioned wave number can be used as an index. That is, a wavenumber region having a peak of one or more wavenumbers selected from the group consisting of ^{1635 to 1643 cm -1} , 1521 to ^{1531 cm -1} , 1153 ^{to 1163 cm -1} , and 1002 ^{to 1012 cm -1 shall be detected.} Can be done. Further, more preferably, the difference from the above-mentioned wave number may be 3 cm ^-1 or less (that is, ± 3 cm ^-1 ).

Depending on the type of seaweed, the peak value detected according to the photosynthetic dye contained in the seaweed is detected in advance, and the wave number region for detecting the first Raman scattered light is appropriately set according to the peak value. May be. In this case, the Raman scattered light corresponding to the seaweed photosynthetic dye is detected in the range of 500cm ^-1 ~1700cm ^-1.

The second Raman scattered light relates to the wavenumber region in which the Raman band derived from the CH stretching oscillations of proteins and carbohydrates is observed. The second detection of Raman scattered light can be detected as an integral value of the peak intensity of Raman scattered light corresponding to such proteins and carbohydrates and the scattered light intensity in a predetermined range. Range for detecting the second Raman scattered light, and the range of 2800cm ^-1 ~3100cm ^-1, the range of 2850cm ^-1 ~3050cm ^-1, may be in the range of 2900cm ^-1 ~3050cm ^-1. Further, it may be limited by the wave number region corresponding to the peak.

For example, as a Raman band derived from CH expansion and contraction vibration, a band having a peak near the wave number of ^{2933 m -1 is observed.} Focusing on this band, it is preferable to detect a wave number region having a peak of a wave number of ^{5 cm -1} or less in which the difference from the wave number of ^{2933 m -1} is 5 cm -1 or less as the second Raman scattered light. As described above in the first Raman scattered light, the spectrum observed by Raman spectroscopy is relatively narrow, and ^{the accuracy of the wave number (cm -1} ) may vary, and the wave number also varies depending on the measuring device or the like. there is a possibility. Therefore, the wave number of the foregoing, are exemplary, for example, for the peak of 2933cm ^-1, there is a possibility that a peak is observed at around 2933cm ^-1 can be used as equivalent.

Therefore, in consideration of these variations, ^{a wave number having a peak difference of 5 cm -1} or less (that is, ± 5 cm ^-1 ) from the above-mentioned wave number can be used as an index. That is, it is possible to detect a wavenumber region having a wavenumber of 2928 to 2938 cm- ^{1 as a peak.} Further, more preferably, the difference from the above-mentioned wave number may be 3 cm ^-1 or less (that is, ± 3 cm ^-1 ).

[Calculation (step S31)]
Step S31 is a step of calculating the Raman scattered light relative intensity ratio regarding the intensity ratio between the first Raman scattered light detected in step S21 and the second Raman scattered light detected in step S22. The Raman scattered light relative intensity ratio can be expressed as "f (first Raman scattered light intensity / second Raman scattered light intensity)".

The Raman scattered light relative intensity ratio may be simply divided by using the scattered light intensity detected as each Raman scattered light, the band integrated value of a predetermined band, or the like. Further, a predetermined coefficient may be applied. Further, when a plurality of values are adopted as the first Raman scattered light and the second Raman scattered light, the relative intensity ratio of the Raman scattered light for each may be used.

For example, as the first Raman scattered light, selects the Raman scattered light intensity of 1638 cm ^-1, as a second Raman scattered light, selects the Raman scattered light intensity of 2933m ^-1. Using these values, it can be obtained by the following equation (1).
Equation (1): Raman scattered light relative intensity ratio (A) = 1638 cm ^-1 Raman scattered light intensity ÷ 2933 m ^-1 Raman scattered light intensity

Further, for example, as a first Raman scattered light, it selects the Raman scattered light intensity of 1526cm ^-1, as a second Raman scattered light, selects the Raman scattered light intensity of 2933m ^-1. Using these values, it can be obtained by the following equation (2).
Equation (2): Raman scattered light relative intensity ratio (B) = 1526 cm ^-1 Raman scattered light intensity ÷ 2933 m ^-1 Raman scattered light intensity

[Evaluation (step S41)
Step S41 is a step of evaluating the quality of seaweed based on the Raman scattered light relative intensity ratio calculated in step S31. For the evaluation of the quality of seaweed, various evaluation criteria such as using standard products are set in consideration of the number of samples and the grade of seaweed based on the Raman scattered light relative intensity ratio, and it is judged as good or bad, grade, etc. It can be evaluated as the degree of. In addition, a plurality of values may be calculated for the Raman scattered light relative intensity ratio, and evaluation criteria are set for each of these multiple ratios for multi-faceted evaluation, or evaluation criteria such as multivariate analysis are provided. May be evaluated.

For example, even if a calibration curve is created based on the Raman scattered light relative intensity ratio calculated for seaweed that has been judged and graded in advance, and the quality is evaluated by comparing it with the calibration curve. good. At this time, a threshold value may be set from the calibration curve, and a pass / fail judgment may be made depending on whether or not the threshold value is satisfied. Alternatively, the Raman scattered light relative intensity ratio itself may be used as a value related to quality based on the calibration curve.

Alternatively, in the classification of samples, manufacturing lots, production areas, manufacturing dates, manufacturing factories, product names, etc., the relative intensity ratio of Raman scattered light is calculated multiple times by changing the evaluation position, etc., and the degree of variation is evaluated for quality. It can also be used as a reference.

The evaluation results can be displayed on a monitor or printed on seaweed or seaweed packaging as appropriate. Alternatively, based on the evaluation result, the seaweed to be measured can be divided into lines and classified as seaweed according to quality. In addition, when a quality abnormality is found, an alarm can be notified.

INDUSTRIAL APPLICABILITY According to the present invention, the quality of seaweed can be evaluated from the viewpoint of the content of umami components. This method is a non-destructive analysis technique based on Raman spectroscopy, and can be used as an evaluation method in place of the sensory test performed in the process from production to distribution of seaweed. Therefore, it can be applied as an alternative method of the following sensory test.

Fair quality evaluation of seaweed is possible based on objective grounds. Conventional sensory tests can only be performed by experienced inspectors, but it is possible to evaluate the quality of seaweed using a machine. The Raman spectrum can be stored in the form of digital data, and it is possible to trace the evaluation contents of each seaweed (traceability). Since the influence of water can be ignored in Raman spectroscopy, it can be applied not only to dried seaweed but also to raw seaweed, and it can also be used for investigating and confirming the growth status of seaweed at aquaculture sites.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is changed.

[Sample (Nori)]
Dry seaweed: Domestic dry seaweed of a wide range of quality from upper grade to lower grade, mainly from the Ariake Sea, was used.

[Test equipment]
Raman scattered light detector: A near-infrared (1064 nm) Raman scattered light detector combined with the following devices was used.
-Laser light source: Kobold Rumba 1064nm, 2000mW, spectral line width <1MHz
-Spectroscope: SpectroPro HRS-300 (diffraction grating: 150 G / mm, 1250 nm, Blaze) manufactured by Teledyne Princeton Instruments.
・ Detector: Andor InGaAs detector DU491A-1.7 type ・ Photometric system: Photometric system consisting of near-infrared achromatec lens and edge filter (Semrock's Ultrastep long-pass edge filter) ・ Optical fiber: 200 μm Core diameter Optical fiber for near-infrared region ・ Detection wavenumber region of Raman spectrum: 300cm ^{-1 to} 3300cm ^-1

[Test Example 1]
The Raman spectrum of dried seaweed was detected, the peak corresponding to the photosynthetic dye and the peak corresponding to the CH expansion and contraction vibration were detected, and the evaluation was performed based on the intensity ratio thereof.

One dry seaweed was measured at different measurement points (points 1 to 5) using a Raman scattered photodetector. FIG. 3 is a diagram showing Raman spectra at different measurement points of dried seaweed by this measurement.

A dry seaweed sample of about 3 to 4 cm square was used. Each measurement point was set at 0.5 mm intervals in the central portion of the dry seaweed sample of about 3 to 4 cm square. As a reference, the difference in thickness between the edge and the center of the seaweed sample is larger, but the position of the measurement point is changed by about 0.1 to 0.2 mm even near the center where the thickness is expected to be relatively uniform. Sometimes you can see a clear difference just by yourself.

A first Raman scattered light, peak detected in the wave number region selected from the range of 500cm ^-1 ~1700cm ^-1 are the following. The band with a peak of about 1638 cm- ¹ gives Raman scattered light corresponding to phycocyanin. In addition, sharp bands with peaks of 1550 cm ^-1 or less (about 1526 cm ^-1 , about 1158 cm ^-1 , about 1007 cm ^-1 ) can obtain Raman scattered light mainly attributed to carotenoids.

A second Raman scattered light, peak detected in the wave number region selected from a range of 2500cm ^-1 ~3300cm ^-1 are the following. A band having a peak near the wave number of ^{2933 m -1} is observed as a Raman band derived from the CH stretching vibration of proteins and carbohydrates.

FIG. 4 is a diagram showing the Raman scattered light intensity (◯) of phycocyanin and carotenoid at five measurement points and the Raman scattered light relative intensity ratio (●). As shown by the white circles in FIG. 4, ^{the Raman scattered light intensities of carotenoid (1526 cm -1} ) and phycocyanin (1638 cm ^-1 ) differed at points 1 to 5, and the coefficient of variation, which is an index of variation, was about 15%. .. By using the Raman scattered light relative intensity ratio, the variation becomes small (coefficient of variation is about 4%), and it can be seen that the content of the photosynthetic dye in consideration of the difference in density and thickness can be evaluated.

[Test Example 2]
Raman spectra of dried seaweed of different qualities were measured. FIG. 5 is a Raman spectrum of dried seaweed. (A) is high-grade seaweed and (b) is low-grade seaweed. This figure shows the Raman spectrum normalized by the intensity of the CH elastic band of proteins and carbohydrates around 2991 cm- ¹ , but the higher-grade seaweed has a large Raman signal intensity of carotenoids and phycocyanins, and the content of photosynthetic pigments It can be seen that the (concentration) is large.

Furthermore, for eight types of dried seaweed, the content and extraction experiments of photosynthetic pigments (carotenoids and phycocyanins) estimated from the Raman spectrum (Reference: Saito, Ofusa. The Bulletin of Japanese Society of Phycology, 22, 130-133, 1974) It was confirmed that there was a correlation with the content of the photosynthetic pigment determined from the above (the amount of pigment contained in 1 g of seaweed mg).

FIG. 6 is a diagram showing the correlation between the content of photosynthetic pigments (phycocyanin and carotenoid) determined from the extraction experiment and the content estimated from the Raman spectrum. As shown in the figure, it was found that the amount of dye determined by the extraction experiment and the amount of dye determined from the Raman spectrum have a direct proportional relationship. From this result, it was confirmed that the content of carotenoid and phycocyanin contained in seaweed can be quantified by non-destructive analysis by Raman spectroscopy.

[Test Example 3]
The Raman spectra of dry seaweed and water measured under the same conditions are shown. FIG. 7 is a Raman spectrum of dried seaweed and water. (A) is dried seaweed and (b) is water. Water O-H stretching vibration in the vicinity of 3400cm ^-1, H-O-H deformation vibration bands are observed near 1650 cm ^-1. Compared to the Raman band derived from the photosynthetic pigment of seaweed, the Raman band of water has a wider line width. Even with a large amount of water in a quartz cell, its signal intensity is weaker than that of the Raman band derived from the photosynthetic pigment of Nori seaweed. Therefore, it was found that the difference in water content caused by the difference in humidity does not affect the observed Raman spectrum.

The present invention can be used for quality evaluation of seaweed and is industrially useful.

100 Quality evaluation device 11 Laser light source 2 Nori 31 Photometric system 32 Optical fiber 33 Spectrometer 34 Detector 4 Detection unit 41 First detection unit 42 Second detection unit 51 Calculation unit 61 Evaluation unit 7 Storage unit 8 Monitor

Claims (4)

The process of irradiating seaweed with excitation light,
Wherein is for detecting the Raman scattered light to laver of the excitation light, a first Raman scattered light detected by the wave number region selected from the range of ^{500cm -1 ~1700cm -1, 2500cm -1 ~3300cm} - ^The step of detecting the second Raman scattered light detected in the wave number region selected from the range of 1 and
A step of calculating the relative intensity ratio of Raman scattered light with respect to the intensity ratio of the first Raman scattered light and the second Raman scattered light.
A method for evaluating the quality of seaweed, which comprises a step of evaluating the quality of the seaweed based on the relative intensity ratio of Raman scattered light. The method for evaluating the quality of seaweed according to claim 1, wherein the excitation light is near-infrared light having a peak in a wavelength region selected from the wavelength range of 800 to 1200 nm. As the first Raman scattered ^{light, 1638cm -1, 1526cm -1, 1158cm} -1, and the difference between the one or more wave number selected from the group consisting of 1007cm ^-1 is a peak following wave numbers 5 cm ^-1 Detects the wavenumber region and
The quality evaluation method for seaweed according to claim 1 or 2, wherein as the second Raman scattered light, a wave number region having a peak of a wave number having a difference of 5 cm ^{-1 or less from the wave number of 2933 m -1 is detected.} .. Irradiation means to irradiate seaweed with excitation light,
Wherein is for detecting the Raman scattered light to laver of the excitation light, a first Raman scattered light detected by the wave number region selected from the range of ^{500cm -1 ~1700cm -1, 2500cm -1 ~3300cm} - A detection means for detecting the second Raman scattered light detected in the wave number region selected from the range of ^{1 and}
A calculation means for calculating the relative intensity ratio of Raman scattered light with respect to the intensity ratio of the first Raman scattered light and the second Raman scattered light.
A seaweed quality evaluation device having an evaluation means for evaluating the quality of the seaweed based on the Raman scattered light relative intensity ratio.

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