Method for cis-isomerization

Abstract

This cis-isomerization method is a method for cis-isomerizing a carotenoid compound, and comprises a suspension preparation step S1, a light irradiation step S2, and a residual particle removal step S3. In the suspension preparation step S1, a suspension containing particles of the carotenoid compound dispersed in a solvent is prepared. In the light irradiation step S2, the suspension prepared in the suspension preparation step S1 is irradiated with pulse laser light to cis-isomerize particles of the carotenoid compound dispersed in the solvent and dissolve the particles in the solvent. In the residual particle removal step S3, particles remaining and dispersed in the solvent are removed. According to the method, it is possible to realize a cis-isomerization method that allows cis-isomerization of a carotenoid compound in a short time and with high efficiency.

Description

Method for cis-isomerization

[0001] The present disclosure relates to a method for cis-isomerizing a carotenoid compound.

[0002] Carotenoid compounds are a group of natural pigment compounds contained in plants and animals. Carotenoid compounds generally have a cis-trans isomer with a basic skeleton of chemical formula C ４０ H ５６ composed of eight isoprene units bonded together. Natural carotenoid compounds are all-trans forms.

[0003] There are many types of carotenoid compounds. Carotenoid compounds are roughly classified into carotenes composed only of carbon atoms and hydrogen atoms, and xanthophylls composed of carbon atoms, hydrogen atoms, and oxygen atoms in addition. Examples of carotenes include α-carotene, β-carotene, lycopene, etc. Examples of xanthophylls include lutein, zeaxanthin, canthaxanthin, astaxanthin, etc.

[0004] Some carotenoid compounds are expected to have medical effects. For example, many carotenoid compounds are said to have antioxidant ability. β-carotene is said to have provitamin activity. Also, lutein is said to be effective in enhancing eye function and preventing eye diseases. Carotenoid compounds can be suitably used as ingredients contained in, for example, foods and drinks, cosmetics, pharmaceuticals, supplements, etc. In order for carotenoid compounds to exhibit the expected effects, it is desirable that the absorption of carotenoid compounds into the human body is good.

[0005] Patent Document 1 and Non-Patent Documents 1 to 3 describe a method for cis-isomerizing a carotenoid compound, and it is also described that the solubility of the carotenoid compound is improved and the absorption in the body is also improved by cis-isomerization.

[0006] The cis-isomerization method described in Patent Document 1 involves irradiating a solution of acetone or the like containing dissolved lycopene with light to cis-isomerize the dissolved lycopene. The cis-isomerization method described in Non-Patent Document 1 involves adding a photosensitizer (methylene blue, chlorophyll a, erythrosine, rose bengal) to an acetone solution containing dissolved lycopene, and then irradiating this solution with light to cis-isomerize the dissolved lycopene. Patent Document 1 and Non-Patent Document 1 list mercury lamps, xenon lamps, halogen lamps, and fluorescent lamps as examples of light sources that emit light to irradiate the solution.

[0007] The cis-isomerization methods described in Non-Patent Documents 2 and 3 involve heating a dichloromethane solution containing β-carotene, astaxanthin, or lycopene to cis-isomerize these carotenoid compounds.

[0008] Japanese Patent Publication No. 2015-51929

[0009] M. Honda, H. Igami, T. Kawana, K. Hayashi, M. Takehara, Y. Inoue, and C. Kitamura, "Photosensitized E / Z Isomerization of (all-E)-Lycopene Aiming at Practical Applications", J. Agric. Food Chem., Vol.62, Issue 47, pp.11353-11356, 2014M. Honda, T. Kodama, H. Kageyama, T. Hibino, Wahyudiono, H. Kanda, and M. Goto, "Enhanced Solubility and Reduced Crystallinity of Carotenoids, β-Carotene and Astaxanthin, by Z-Isomerization", European Journal of Lipid Science and Technology, Vol.120, Issue 11, 1800191, 2018K. Murakami, M. Honda, R. Takemura, T. Fukaya, M. Kubota, Wahyudiono, H. Kanda, and M. Goto, "The thermal Z-isomerization-induced change in solubility and physical properties of (all-E)-lycopene", Biochem. Biophys. Res. Commun., Vol.491, Issue 2, pp.317-322, 2017

[0010] The cis-isomerization methods described in Patent Document 1 and Non-Patent Documents 1-3, respectively, require a long time to cis-isomerize carotenoid compounds and have low cis-isomerization efficiency.

[0011] The embodiment aims to provide a cis-isomerization method that can cis-isomerize carotenoid compounds quickly and efficiently.

[0012] The embodiment is a cis isomerization method. The cis isomerization method of the embodiment is a method for cis isomerizing a carotenoid compound. The cis isomerization method comprises (1) a suspension preparation step of preparing a suspension in which particles of a carotenoid compound are dispersed in a solvent, and (2) a light irradiation step of irradiating the suspension with pulsed laser light to cis isomerize the particles of the carotenoid compound and dissolve them in the solvent.

[0013] The embodiment is a method for producing food and beverages. The method for producing food and beverages involves producing food and beverages using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described above as a raw material.

[0014] The embodiment is a method for manufacturing cosmetics. The method for manufacturing cosmetics involves manufacturing cosmetics using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described above as a raw material.

[0015] The embodiment is a method for manufacturing a pharmaceutical product. The method for manufacturing a pharmaceutical product involves manufacturing a pharmaceutical product using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described above as a raw material.

[0016] The embodiment is a method for manufacturing a supplement. The method for manufacturing a supplement involves manufacturing a supplement using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described above as a raw material.

[0017] According to the cis-isomerization method of this embodiment, carotenoid compounds can be cis-isomerized with high efficiency in a short time.

[0018] Figure 1 is a flowchart of the cis-isomerization method of this embodiment. Figure 2 is a diagram showing the configuration of an apparatus suitable for carrying out the light irradiation step S2 in the cis-isomerization method of this embodiment. Figure 3 is a diagram showing the absorption spectrum obtained when pulsed laser light was irradiated in the first embodiment. Figure 4 is a diagram showing the absorption spectrum obtained when cw laser light was irradiated in the comparative example. Figure 5 is a diagram showing the absorption spectrum obtained in the second embodiment. Figure 6 is a graph showing the relationship between absorbance at a wavelength of 450 nm and irradiation light intensity obtained in the second embodiment. Figure 7 is a diagram showing the absorption spectrum obtained when β-carotene was used in the third embodiment. Figure 8 is a diagram showing the absorption spectrum obtained when astaxanthin was used in the third embodiment. Figure 9 is a diagram showing the absorption spectrum obtained when lycopene was used in the third embodiment. Figure 10 is a diagram showing the absorption spectrum obtained when α-carotene was used in the third embodiment. Figure 11 is a diagram showing the absorption spectrum obtained when canthaxanthin was used in the third embodiment. Figure 12 is a diagram showing the absorption spectrum obtained when zeaxanthin was used in the third embodiment. Figure 13 shows the absorption spectrum obtained when lutein was used in the third example. Figure 14 shows the absorption spectrum obtained when ethanol was used in the fourth example. Figure 15 shows the absorption spectrum obtained when methanol was used in the fourth example. Figure 16 shows the absorption spectrum obtained when acetone was used in the fourth example. Figure 17 shows the absorption spectrum obtained when hexane was used in the fourth example. Figure 18 shows the absorption spectrum obtained when ethanol was used in the fifth example. Figure 19 shows the absorption spectrum obtained when methanol was used in the fifth example. Figure 20 shows the absorption spectrum obtained when acetone was used in the fifth example. Figure 21 shows the absorption spectrum obtained when hexane was used in the fifth example. Figure 22 shows the absorption spectrum obtained in the sixth example for each irradiation wavelength in the range of 460 nm to 520 nm. Figure 23 shows the absorption spectrum obtained in the sixth example for each irradiation wavelength in the range of 515 nm to 550 nm.Figure 24 shows the absorption spectra obtained in the sixth embodiment for each irradiation wavelength in the range of 540 nm to 600 nm. Figure 25 is a graph showing the relationship between absorbance at 445 nm and irradiation wavelength obtained in the sixth embodiment. Figure 26 shows the absorption spectra obtained in the seventh embodiment for each irradiation wavelength in the range of 450 nm to 560 nm. Figure 27 shows the absorption spectra obtained in the seventh embodiment for each irradiation wavelength in the range of 550 nm to 590 nm. Figure 28 shows the absorption spectra obtained in the seventh embodiment for each irradiation wavelength in the range of 580 nm to 650 nm. Figure 29 is a graph showing the relationship between absorbance at 470 nm and irradiation wavelength obtained in the seventh embodiment. Figure 30 shows the absorption spectrum obtained in the eighth embodiment when pulsed laser light irradiation was performed under the first condition (irradiation wavelength 532 nm, pulse width 100 μs). Figure 31 shows the absorption spectrum obtained in the 8th embodiment when pulsed laser light irradiation was performed under the second condition (irradiation wavelength 420 nm, pulse width 5 ns). Figure 32 shows the absorption spectrum obtained in the 8th embodiment when pulsed laser light irradiation was performed under the third condition (irradiation wavelength 420 nm, pulse width 35 fs). Figure 33 is a graph showing the relationship between absorbance at a wavelength of 450 nm and irradiation light energy when the irradiation wavelength is 532 nm and the pulse widths are 5 ns and 100 μs, respectively. Figure 34 is a graph showing the relationship between absorbance at a wavelength of 450 nm and irradiation light energy when the irradiation wavelength is 420 nm and the pulse widths are 5 ns and 35 fs, respectively. Figure 35 is a chromatogram showing the results of HPLC component analysis of the solution obtained when pulsed laser light irradiation was performed under the third condition (irradiation wavelength 420 nm, pulse width 35 fs, irradiation time 5 minutes) in the 8th embodiment. Figure 36 shows the absorption spectrum obtained in the ninth embodiment when pulsed laser light irradiation was performed under the first condition (irradiation light wavelength 532 nm, pulse width 100 μs). Figure 37 shows the absorption spectrum obtained in the ninth embodiment when pulsed laser light irradiation was performed under the second condition (irradiation light wavelength 420 nm, pulse width 5 ns).Figure 38 shows the absorption spectrum obtained in the ninth embodiment when pulsed laser light irradiation was performed under the third condition (irradiation wavelength 420 nm, pulse width 35 fs). Figure 39 is a graph showing the relationship between absorbance at a wavelength of 470 nm and irradiation energy when the irradiation wavelength is 532 nm and the pulse widths are 5 ns and 100 μs, respectively, in the ninth embodiment. Figure 40 is a graph showing the relationship between absorbance at a wavelength of 470 nm and irradiation energy when the irradiation wavelength is 420 nm and the pulse widths are 5 ns and 35 fs, respectively, in the ninth embodiment. Figure 41 is a chromatogram showing the results of HPLC component analysis of the solution obtained when pulsed laser light irradiation was performed under the third condition (irradiation wavelength 420 nm, pulse width 35 fs, irradiation time 5 minutes), in the ninth embodiment.

[0019] Embodiments of the cis-isomerization method will be described in detail below with reference to the attached drawings. The present invention is not limited to these examples, but is intended to include all modifications within the meaning and scope equivalent to the claims as shown in the claims.

[0020] Figure 1 is a flowchart of the cis-isomerization method of this embodiment. The cis-isomerization method of this embodiment is a method for cis-isomerizing a carotenoid compound and comprises a suspension preparation step S1, a light irradiation step S2, and a residual particle removal step S3.

[0021] In the suspension preparation step S1, a suspension is prepared by dispersing carotenoid compound particles in a solvent. The type of carotenoid compound can be any. The solvent can be any, but an organic solvent is preferred, such as ethanol, methanol, acetone, or hexane. It is preferable to degas the suspension to remove oxygen or to bubble it with an inert gas such as nitrogen or argon, but this is not necessary. Performing these treatments improves the cis-isomerization efficiency in the subsequent light irradiation step S2.

[0022] In the light irradiation step S2, the suspension prepared in the suspension preparation step S1 is irradiated with pulsed laser light to cis-isomerize the carotenoid compound particles dispersed in the solvent and dissolve them in the solvent. The pulse width of the pulsed laser light may be a value within a wide range including several nanoseconds to several hundred nanoseconds, and may be several hundred microseconds or several tens of fs.

[0023] The central wavelength of the pulsed laser light is preferably within the range of 275 nm to 700 nm, where the suspension absorbs light, and there is a more suitable range depending on the type of carotenoid compound. In the following, the wavelength range in which cis isomerization and photodissolution occur most efficiently is defined as the wavelength range in which cis isomerization and photodissolution occur efficiently, where the absorbance is 1 / 2 or more of the absorbance at the wavelength at which cis isomerization and photodissolution occur most efficiently (maximum wavelength).

[0024] The wavelength of light at which cis isomerization and photodissolution occur most efficiently is hardly absorbed in solutions where carotenoid compound particles are not dispersed (not in suspension). The wavelength of absorption maximum in the solution is λ peak Therefore, the wavelength range in which cis isomerization and photodissolution occur is λ peak ~λ peak The wavelength range is +180 nm, and the wavelength range in which cis isomerization and photodissolution occur efficiently is λ peak +40 nm to λ peak This is within the range of +120 nm.

[0025] In the case of β-carotene, the suspension absorbs light when the central wavelength is in the range of 275 nm to 700 nm. Cis isomerization and photodissolution occur when the central wavelength is in the range of 450 nm to 600 nm. Cis isomerization and photodissolution occur efficiently when the central wavelength is in the range of 500 nm to 560 nm. Cis isomerization and photodissolution occur most efficiently when the central wavelength is 530 nm.

[0026] In the case of astaxanthin, the suspension absorbs light when the central wavelength is in the range of 350 nm to 700 nm. Cis isomerization and photodissolution occur when the central wavelength is in the range of 450 nm to 650 nm. Cis isomerization and photodissolution occur efficiently when the central wavelength is in the range of 530 nm to 620 nm. Cis isomerization and photodissolution occur most efficiently when the central wavelength is 580 nm.

[0027] In the case of lycopene, the suspension absorbs light when the central wavelength is in the range of 350 nm to 700 nm. When the central wavelength is in the range of 500 nm to 620 nm, cis isomerization and photodissolution occur. When the central wavelength is in the range of 500 nm to 590 nm, cis isomerization and photodissolution occur efficiently. When the central wavelength is 530 nm, cis isomerization and photodissolution occur most efficiently.

[0028] In the light irradiation step S2, the cis-isomerized carotenoid compound dissolves in the solvent. On the other hand, if particles of the carotenoid compound that have not been cis-isomerized remain, these residual particles remain dispersed in the solvent. Therefore, in the residual particle removal step S3 after the light irradiation step S2, it is preferable to remove the particles remaining dispersed in the solvent by filtration or centrifugation.

[0029] The cis-isomerization method of this embodiment can cis-isomerize carotenoid compounds in a short time and with high efficiency compared to the cis-isomerization methods described in Patent Document 1 and Non-Patent Documents 1 to 3.

[0030] By using the cis-isomerization method of this embodiment to produce carotenoid compounds as raw materials, it is possible to manufacture food and beverages, cosmetics, pharmaceuticals, and supplements.

[0031] Foods, cosmetics, pharmaceuticals, and supplements containing cis-isomerized carotenoid compounds are expected to have health-maintaining and beauty benefits based on the efficacy of these carotenoid compounds (e.g., antioxidant capacity, provitamin activity, enhanced eye function, prevention of eye diseases, etc.) due to their good absorption into the body. Examples of foods and beverages containing carotenoid compounds include various drinks, as well as jellies, jams, sherbets, and the like.

[0032] Figure 2 shows the configuration of an apparatus suitable for performing the light irradiation step S2 in the cis isomerization method of this embodiment. The cis isomerization apparatus 1 shown in this figure comprises a pulsed laser light source 11, a dimming device 12, a beam splitter 13, a shutter 14, a sample cell 15, a beam trap 16, and a power meter 17.

[0033] The pulsed laser light source 11 outputs pulsed laser light to be irradiated onto the sample in the sample cell 15. The dimming unit 12 receives the pulsed laser light output from the pulsed laser light source 11, adjusts the intensity of the pulsed laser light, and outputs it to the beam splitter 13. The beam splitter 13 receives the pulsed laser light output from the dimming unit 12 and splits the pulsed laser light into two. The beam splitter 13 outputs one of the split beams to the shutter 14 and the other split beam to the power meter 17.

[0034] The shutter 14 receives the pulsed laser light, which is one of the branched beams output from the beam splitter 13. The shutter 14 can switch between allowing the pulsed laser light to pass through and blocking it, and sets the period during which the pulsed laser light is irradiated onto the sample in the sample cell 15.

[0035] The sample cell 15 is a cell that contains the suspension prepared in the suspension preparation step S1. The sample cell 15 is preferably made of a material that absorbs pulsed laser light poorly, such as quartz glass. Furthermore, the sample cell 15 is preferably equipped with a function to agitate the suspension to prevent the particles in the suspension from settling.

[0036] The pulsed laser light that reaches the sample cell 15 from the shutter 14 is irradiated onto the suspension in the sample cell 15. A portion of the pulsed laser light is absorbed or scattered by the suspension, and the pulsed laser light that passes through the suspension is output to the beam trap 16. The beam trap 16 traps the pulsed laser light that has arrived from the sample cell 15.

[0037] The power meter 17 inputs the pulsed laser light, which is the other branched light output from the beam splitter 13, and measures the average power of the pulsed laser light. By adjusting the light attenuator 12 based on the measurement value by the power meter 17 and the branching ratio in the beam splitter 13, the average power of the pulsed laser light irradiated to the sample in the sample cell 15 can be set.

[0038] Next, an example of the cis-isomerization method will be described. In each example, suspension preparation, light irradiation, and residual particle removal were performed under various conditions, and then the absorption spectrum of the sample solution was measured. Based on this absorption spectrum, the degree of photo-isomerization of the carotenoid compound by light irradiation was evaluated. The scales on the vertical axis are not common in the figures showing the absorption spectra.

[0039] (First Example)

[0040] In the first example, the change in the absorption spectrum when the ethanol suspension of β-carotene was irradiated with pulsed laser light was compared with the case of a comparative example irradiated with cw laser light. A suspension was prepared by putting 1 mg of β-carotene per 1 mL of ethanol and stirring well.

[0041] For both the pulsed laser light and the cw laser light, the wavelength was 532 nm, the average power was 100 mW, the irradiation beam diameter was 1 mm, and the irradiation time was each value in the range of 0 minute to 60 minutes. The pulse repetition frequency of the pulsed laser light was 500 Hz, and the pulse width was 5 ns. After the laser light irradiation, the sample solution was centrifuged to remove residual particles, and the supernatant obtained thereby was diluted 100 times, and the absorption spectrum of the diluted solution was measured.

[0042] FIG. 3 is a diagram showing the absorption spectrum obtained when the pulsed laser light was irradiated in the first example. FIG. 4 is a diagram showing the absorption spectrum obtained when the cw laser light was irradiated in the comparative example.

[0043] As shown in these figures, in the case of the comparative example in which a CW laser beam was irradiated onto a suspension of β-carotene, no change in the absorption spectrum was observed. On the other hand, when a pulsed laser beam was irradiated onto a suspension of β-carotene, it was confirmed that the absorbance increased as the irradiation time became longer. Also, when a pulsed laser beam was irradiated, the solubility of β-carotene increased as the irradiation time became longer.

[0044] The improvement in solubility and the change in the absorption spectrum when a pulsed laser beam was irradiated are considered to be due to the photo-isomerization of the 9th or 13th position of β-carotene, which was in the all-trans form before light irradiation, into the cis state. Also, when the supernatant after centrifugation in the case of irradiation with a pulsed laser beam was subjected to component analysis by high performance liquid chromatography (HPLC), it was confirmed that β-carotene was cis-isomerized by the pulsed laser beam irradiation.

[0045] From the above, it can be seen that by irradiating a pulsed laser beam onto an ethanol suspension of β-carotene, the β-carotene in the suspension could be cis-isomerized.

[0046] (Second Embodiment)

[0047] In the second embodiment, the change in the absorption spectrum when a pulsed laser beam with various average powers was irradiated onto an ethanol suspension of β-carotene was confirmed. A suspension was prepared by putting in 1 mg of β-carotene per 1 mL of ethanol and stirring well.

[0048] Regarding the pulsed laser beam irradiated onto the suspension, the wavelength was 532 nm, the average power was each value in the range of 0 mW to 600 mW, the pulse repetition frequency was 20 Hz, the pulse width was 5 ns, the irradiation beam diameter was 5.4 mm, and the irradiation time was 30 seconds. After the laser beam irradiation, the suspension was filtered with a syringe filter having a pore size of 0.22 μm to remove residual particles, and the solution thus obtained was diluted 100-fold, and the absorption spectrum of the diluted solution was measured.

[0049] Figure 5 shows the absorption spectrum obtained in the second embodiment. Figure 6 is a graph showing the relationship between absorbance at a wavelength of 450 nm and irradiation light intensity obtained in the second embodiment.

[0050] As shown in these figures, in the low irradiation light intensity range (approximately 20 mW or less), the increase in absorbance was proportional to the square of the irradiation light intensity. As the irradiation light intensity increased, the absorbance increased in proportion to the irradiation light intensity. At irradiation light intensities of 200 mW or higher, the change in absorbance in response to changes in irradiation light intensity tended to decrease.

[0051] (Third embodiment)

[0052] In the third example, changes in the absorption spectra of ethanol suspensions of various types of carotenoid compounds were observed when irradiated with pulsed laser light. The carotenoid compounds used were β-carotene, astaxanthin, lycopene, α-carotene, canthaxanthin, zeaxanthin, and lutein. The solvent used was ethanol or methanol. Each carotenoid compound was placed in the solvent and thoroughly stirred to prepare a suspension, which was then placed in a 1 cm quartz cell.

[0053] For β-carotene, astaxanthin, lycopene, α-carotene, and canthaxanthin, 500 μg was added per 1 mL of ethanol. For zeaxanthin, 300 μg was added per 1 mL of methanol. For lutein, 50 mg of lutein granules with a 10% lutein content was added per 1 mL of methanol.

[0054] For the pulsed laser light irradiated onto the suspension in a quartz cell, the wavelength was 532 nm, the average power was 100 mW, the pulse repetition frequency was 20 Hz, the pulse width was 5 ns, the irradiation beam diameter was 5 mm, and the irradiation time ranged from 0 to 10 minutes. After laser irradiation, the suspension was filtered through a syringe filter with a pore size of 0.22 μm to remove residual particles, and the resulting solution was diluted 100-fold. The absorption spectrum of the diluted solution was then measured.

[0055] Figure 7 shows the absorption spectrum obtained when β-carotene was used in the third example. Figure 8 shows the absorption spectrum obtained when astaxanthin was used in the third example. Figure 9 shows the absorption spectrum obtained when lycopene was used in the third example. Figure 10 shows the absorption spectrum obtained when α-carotene was used in the third example. Figure 11 shows the absorption spectrum obtained when canthaxanthin was used in the third example. Figure 12 shows the absorption spectrum obtained when zeaxanthin was used in the third example. Figure 13 shows the absorption spectrum obtained when lutein was used in the third example.

[0056] As shown in these figures, for all carotenoid compounds, irradiating an ethanol suspension with pulsed laser light can cause the carotenoid compounds in the suspension to undergo cis-isomerization, and it can be seen that photodissolution and photoisomerization progress as the irradiation time increases.

[0057] (Fourth embodiment)

[0058] In the fourth example, changes in the absorption spectra of β-carotene suspensions prepared using various solvents were observed when irradiated with pulsed laser light. The solvents used were ethanol, methanol, acetone, and hexane. 1 mg of β-carotene was added to 1 mL of each solvent and thoroughly stirred to prepare a suspension, which was then placed in a 1 cm quartz cell.

[0059] For the pulsed laser light irradiated onto the suspension in a quartz cell, the wavelength was 532 nm, the average power was 15 mW, the pulse repetition frequency was 10 Hz, the pulse width was 5 ns, the irradiation beam diameter was 2 mm, and the irradiation time ranged from 0 to 10 minutes. After laser irradiation, the sample solution was centrifuged to remove residual particles, and the resulting supernatant was diluted 100-fold. The absorption spectrum of the diluted solution was then measured.

[0060] Figure 14 shows the absorption spectrum obtained when ethanol was used in the fourth example. Figure 15 shows the absorption spectrum obtained when methanol was used in the fourth example. Figure 16 shows the absorption spectrum obtained when acetone was used in the fourth example. Figure 17 shows the absorption spectrum obtained when hexane was used in the fourth example.

[0061] As shown in these figures, in all solvents, irradiating a suspension of β-carotene with pulsed laser light can cause cis-isomerization of the β-carotene in the suspension, and it can be seen that photodissolution and photoisomerization progress as the irradiation time increases.

[0062] (Fifth Example)

[0063] In the fifth example, changes in the absorption spectra of astaxanthin suspensions prepared using various solvents were observed when irradiated with pulsed laser light. The solvents used were ethanol, methanol, acetone, and hexane. 500 μg of astaxanthin was added to 1 mL of each solvent and thoroughly stirred to prepare a suspension, which was then placed in a 1 cm quartz cell.

[0064] Pulsed laser irradiation, residual particle removal, and absorption spectrum measurement were performed in the same manner as in the fourth embodiment.

[0065] Figure 18 shows the absorption spectrum obtained when ethanol was used in the fifth example. Figure 19 shows the absorption spectrum obtained when methanol was used in the fifth example. Figure 20 shows the absorption spectrum obtained when acetone was used in the fifth example. Figure 21 shows the absorption spectrum obtained when hexane was used in the fifth example.

[0066] As shown in these figures, in all solvents, irradiating a suspension of astaxanthin with pulsed laser light can cause cis-isomerization of the astaxanthin in the suspension, and it can be seen that photodissolution and photoisomerization progress as the irradiation time increases. In particular, the effect of cis-isomerization of astaxanthin is greater when ethanol or methanol is used as the solvent.

[0067] (Sixth example)

[0068] In the sixth example, changes in the absorption spectrum were observed when pulsed laser light of various wavelengths was irradiated onto an ethanol suspension of β-carotene. A suspension was prepared by adding 1 mg of β-carotene to 1 mL of ethanol and stirring thoroughly, and this suspension was placed in a 1 cm quartz cell.

[0069] The pulsed laser light irradiated onto the suspension in a quartz cell had wavelengths ranging from 460 nm to 600 nm, an average power of 15 mW, a pulse repetition frequency of 10 Hz, a pulse width of 5 ns, an irradiation beam diameter of 2 mm, and an irradiation time of 15 minutes. A tunable pulsed laser light source was used. After laser irradiation, the sample solution was centrifuged to remove residual particles, and the resulting supernatant was diluted 100-fold. The absorption spectrum of the diluted solution was then measured.

[0070] Figure 22 shows the absorption spectra obtained in the sixth embodiment for each irradiation wavelength in the range of 460 nm to 520 nm. Figure 23 shows the absorption spectra obtained in the sixth embodiment for each irradiation wavelength in the range of 515 nm to 550 nm. Figure 24 shows the absorption spectra obtained in the sixth embodiment for each irradiation wavelength in the range of 540 nm to 600 nm. Figure 25 is a graph showing the relationship between absorbance at a wavelength of 445 nm and the irradiation wavelength obtained in the sixth embodiment.

[0071] In the case of a β-carotene suspension, light absorption occurs in the wavelength range of 275 nm to 700 nm. As shown in these figures, by irradiating the β-carotene suspension with pulsed laser light at any wavelength within the broad wavelength range tested, it was possible to cis-isomerize the β-carotene in the suspension.

[0072] When pulsed laser light with a wavelength within the range of 500 nm to 560 nm was irradiated onto a suspension of β-carotene, cis-isomerization of β-carotene was achieved more effectively. In particular, cis-isomerization of β-carotene was most effective when pulsed laser light with a wavelength of 530 nm was irradiated onto the suspension of β-carotene.

[0073] (Seventh Example)

[0074] In the seventh example, changes in the absorption spectrum were observed when pulsed laser light of various wavelengths was irradiated onto an ethanol suspension of astaxanthin. A suspension was prepared by adding 500 μg of astaxanthin to 1 mL of ethanol and stirring thoroughly, and this suspension was placed in a 1 cm quartz cell.

[0075] Pulsed laser irradiation, residual particle removal, and absorption spectrum measurement were performed in the same manner as in the sixth example. However, the irradiation wavelength was within the range of 450 nm to 650 nm.

[0076] Figure 26 shows the absorption spectra obtained in the seventh embodiment for each irradiation wavelength in the range of 450 nm to 560 nm. Figure 27 shows the absorption spectra obtained in the seventh embodiment for each irradiation wavelength in the range of 550 nm to 590 nm. Figure 28 shows the absorption spectra obtained in the seventh embodiment for each irradiation wavelength in the range of 580 nm to 650 nm. Figure 29 is a graph showing the relationship between absorbance at 470 nm and irradiation wavelength obtained in the seventh embodiment.

[0077] In the case of astaxanthin suspension, light absorption occurs in the wavelength range of 350 nm to 700 nm. As shown in these figures, by irradiating the astaxanthin suspension with pulsed laser light at any wavelength within the broad wavelength range tested, it was possible to cis-isomerize the astaxanthin in the suspension.

[0078] When pulsed laser light with a wavelength within the range of 530 nm to 620 nm was irradiated onto an astaxanthin suspension, cis-isomerization of astaxanthin was more effective. In particular, cis-isomerization of astaxanthin was most effective when pulsed laser light with a wavelength of 580 nm was irradiated onto an astaxanthin suspension.

[0079] (Eighth example)

[0080] In the eighth example, changes in the absorption spectrum were observed when pulsed laser light of various pulse widths was irradiated onto an ethanol suspension of β-carotene. A suspension was prepared by adding 1 mg of β-carotene to 1 mL of ethanol and stirring thoroughly, and this suspension was placed in a 1 cm quartz cell.

[0081] Pulsed laser light irradiation of a suspension in a quartz cell was performed under the following three conditions. In the first condition, the wavelength was 532 nm, the average power was 30 mW, the pulse repetition frequency was 5 Hz, the pulse width was 100 μs, the irradiation beam diameter was 1 mm, and the irradiation time ranged from 0 to 9 minutes. In the second condition, the wavelength was 420 nm, the average power was 20 mW, the pulse repetition frequency was 20 Hz, the pulse width was 5 ns, the irradiation beam diameter was 1 mm, and the irradiation time ranged from 0 to 20 minutes.

[0082] Under the third condition, the wavelength was 420 nm, the average power was 87 mW, the pulse repetition frequency was 1 kHz, the pulse width was 35 fs, the irradiation beam diameter was 1 mm, and the irradiation time ranged from 0 to 20 minutes. After irradiation with laser light under each of the first to third conditions, the suspension was filtered through a syringe filter with a pore size of 0.22 μm to remove residual particles. The resulting solution was then diluted 10-fold, and the absorption spectrum of the diluted solution was measured.

[0083] Figure 30 shows the absorption spectrum obtained in the eighth embodiment when pulsed laser light irradiation was performed under the first condition (irradiation light wavelength 532 nm, pulse width 100 μs). Figure 31 shows the absorption spectrum obtained in the eighth embodiment when pulsed laser light irradiation was performed under the second condition (irradiation light wavelength 420 nm, pulse width 5 ns). Figure 32 shows the absorption spectrum obtained in the eighth embodiment when pulsed laser light irradiation was performed under the third condition (irradiation light wavelength 420 nm, pulse width 35 fs).

[0084] As shown in these figures, irradiating a suspension of β-carotene with pulsed laser light at any of the pulse widths tested successfully cis-isomerized the β-carotene in the suspension. This indicates that cis-isomerization of β-carotene can be achieved by irradiating a suspension with pulsed laser light with pulse widths ranging from at least several tens of fs to several hundred microseconds.

[0085] Figure 33 is a graph showing the relationship between absorbance at a wavelength of 450 nm and the irradiation light energy when the irradiation light wavelength is 532 nm and the pulse widths are 5 ns and 100 μs, respectively, in the eighth embodiment. Figure 34 is a graph showing the relationship between absorbance at a wavelength of 450 nm and the irradiation light energy when the irradiation light wavelength is 420 nm and the pulse widths are 5 ns and 35 fs, respectively, in the eighth embodiment.

[0086] As shown in these figures, regardless of whether microsecond, nanosecond, or femtosecond pulsed laser light was used, the higher the irradiation energy, the more advanced the cis-isomerization of β-carotene. Furthermore, at the same irradiation energy, irradiating a β-carotene suspension with nanosecond pulsed laser light was the most effective way to cis-isomerize β-carotene.

[0087] Figure 35 is a chromatogram showing the results of HPLC component analysis of the solution obtained when pulsed laser light irradiation was performed under the third condition (irradiation wavelength 420 nm, pulse width 35 fs, irradiation time 5 minutes) in the eighth embodiment. This chromatogram was obtained at an observation wavelength of 455 nm.

[0088] This shows that before irradiation with femtosecond pulsed laser light, the all-trans isomer at the 17.2 min position is predominant. However, after irradiation with femtosecond pulsed laser light for 5 minutes, the all-trans isomer at the 17.2 min position increases, and the 13-cis isomer at the 14.2 min position and the 9-cis isomer at the 19.4 min position appear. This indicates that photoisomerization occurs due to irradiation with femtosecond pulsed laser light, and the cis isomer is formed.

[0089] (Ninth Example)

[0090] In the ninth example, changes in the absorption spectrum were observed when pulsed laser light of various pulse widths was irradiated onto an ethanol suspension of astaxanthin. A suspension was prepared by adding 500 μg of astaxanthin to 1 mL of ethanol and stirring thoroughly, and this suspension was placed in a 1 cm quartz cell.

[0091] Pulsed laser irradiation, residual particle removal, and absorption spectrum measurement were performed in the same manner as in the eighth example.

[0092] Figure 36 shows the absorption spectrum obtained in the ninth embodiment when pulsed laser light irradiation was performed under the first condition (irradiation light wavelength 532 nm, pulse width 100 μs). Figure 37 shows the absorption spectrum obtained in the ninth embodiment when pulsed laser light irradiation was performed under the second condition (irradiation light wavelength 420 nm, pulse width 5 ns). Figure 38 shows the absorption spectrum obtained in the ninth embodiment when pulsed laser light irradiation was performed under the third condition (irradiation light wavelength 420 nm, pulse width 35 fs).

[0093] As shown in these figures, irradiating a suspension of astaxanthin with pulsed laser light at any of the pulse widths tested resulted in cis-isomerization of the astaxanthin in the suspension. This indicates that cis-isomerization of astaxanthin can be achieved by irradiating a suspension with pulsed laser light with pulse widths ranging from at least several tens of fs to several hundred microseconds.

[0094] Figure 39 is a graph showing the relationship between absorbance at a wavelength of 470 nm and the irradiation light energy when the irradiation light wavelength is 532 nm and the pulse widths are 5 ns and 100 μs, respectively, in the ninth embodiment. Figure 40 is a graph showing the relationship between absorbance at a wavelength of 470 nm and the irradiation light energy when the irradiation light wavelength is 420 nm and the pulse widths are 5 ns and 35 fs, respectively, in the ninth embodiment.

[0095] As shown in these figures, irradiation with nanosecond pulsed laser light resulted in a greater cis-isomerization effect of astaxanthin compared to irradiation with microsecond pulsed laser light, and the cis-isomerization of astaxanthin progressed with increasing irradiation light energy. When irradiated with microsecond pulsed laser light and femtosecond pulsed laser light, the change in the degree of cis-isomerization of astaxanthin was small even when the irradiation light energy was increased.

[0096] Comparing femtosecond pulsed laser irradiation with nanosecond pulsed laser irradiation, cis isomerization was more advanced with femtosecond pulsed laser irradiation in the range of low irradiation light energy, while cis isomerization was more advanced with nanosecond pulsed laser irradiation in the range of high irradiation light energy.

[0097] Figure 41 is a chromatogram showing the results of HPLC component analysis of the solution obtained in the ninth embodiment when pulsed laser light irradiation was performed under the third condition (irradiation wavelength 420 nm, pulse width 35 fs, irradiation time 5 minutes). This chromatogram was obtained at an observation wavelength of 476 nm.

[0098] This shows that although the amount of change is small due to the large amount of decomposition, the peak of the cis isomer at the 36-minute position increases after irradiation with femtosecond pulsed laser light for 5 minutes, indicating that photoisomerization also occurs with femtosecond pulsed laser light irradiation.

[0099] The cis-isomerization method is not limited to the embodiments and configuration examples described above, and various modifications are possible.

[0100] The first embodiment of the cis isomerization method according to the above embodiment is a method for cis isomerizing a carotenoid compound, comprising: (1) a suspension preparation step of preparing a suspension in which particles of the carotenoid compound are dispersed in a solvent; and (2) a light irradiation step of irradiating the suspension with pulsed laser light to cis isomerize the particles of the carotenoid compound and dissolve them in the solvent.

[0101] In the cis-isomerization method of the second embodiment, the configuration of the first embodiment may further include a residual particle removal step for removing carotenoid compound particles that remain dispersed in the solvent after the light irradiation step.

[0102] In the third embodiment of the cis-isomerization method, the solvent may be ethanol, methanol, acetone, or hexane in the configuration of the first or second embodiment.

[0103] In the cis-isomerization method of the fourth embodiment, in any of the configurations of the first to third embodiments, the carotenoid compound may be α-carotene, β-carotene, lycopene, astaxanthin, or lutein.

[0104] In the cis isomerization method of the fifth embodiment, in any of the configurations of the first to fourth embodiments, the suspension may be irradiated with pulsed laser light having a central wavelength in the wavelength range of 275 nm to 700 nm during the light irradiation step.

[0105] In the cis-isomerization method of the sixth embodiment, in any of the configurations of the first to fourth embodiments, if the carotenoid compound is β-carotene, the suspension may be irradiated with pulsed laser light having a central wavelength in the wavelength range of 450 nm to 600 nm during the photoirradiation step.

[0106] In the cis-isomerization method of the seventh embodiment, in any of the configurations of the first to fourth embodiments, if the carotenoid compound is astaxanthin, the suspension may be irradiated with pulsed laser light having a central wavelength in the wavelength range of 450 nm to 650 nm during the photoirradiation step.

[0107] In the cis-isomerization method of the eighth embodiment, in any of the configurations of the first to fourth embodiments, if the carotenoid compound is lycopene, the suspension may be irradiated with pulsed laser light having a central wavelength in the wavelength range of 500 nm to 620 nm during the photoirradiation step.

[0108] The method for producing food and beverages according to the above embodiment involves producing food and beverages using a carotenoid compound that has been cis-isomerized by the cis-isomerization method of the above configuration as a raw material.

[0109] The method for producing cosmetics according to the above embodiment involves producing cosmetics using a carotenoid compound that has been cis-isomerized by the cis-isomerization method of the above configuration as a raw material.

[0110] The method for producing a pharmaceutical product according to the above embodiment involves producing a pharmaceutical product using a carotenoid compound that has been cis-isomerized by the cis-isomerization method of the above configuration as a raw material.

[0111] The method for producing a supplement according to the above embodiment involves producing a supplement using a carotenoid compound that has been cis-isomerized by the cis-isomerization method of the above configuration as a raw material.

[0112] The embodiment can be used as a cis-isomerization method that can cis-isomerize carotenoid compounds quickly and efficiently.

[0113] 1...Cis isomerization apparatus, 11...Pulsed laser light source, 12...Density reducer, 13...Beam splitter, 14...Shutter, 15...Sample cell, 16...Beam trap, 17...Power meter.

Claims

1. A cis isomerization method comprising: a suspension preparation step of preparing a suspension in which particles of a carotenoid compound are dispersed in a solvent; and a light irradiation step of irradiating the suspension with pulsed laser light to cis isomerize the particles of the carotenoid compound and dissolve them in the solvent.

2. The cis-isomerization method according to claim 1, further comprising a residual particle removal step for removing particles of the carotenoid compound that remain and are dispersed in the solvent after the light irradiation step.

3. The cis-isomerization method according to claim 1 or 2, wherein the solvent is ethanol, methanol, acetone, or hexane.

4. The cis-isomerization method according to any one of claims 1 to 3, wherein the carotenoid compound is α-carotene, β-carotene, lycopene, astaxanthin, or lutein.

5. The cis isomerization method according to any one of claims 1 to 4, wherein in the light irradiation step, pulsed laser light having a central wavelength in the wavelength range of 275 nm to 700 nm is irradiated onto the suspension.

6. The cis-isomerization method according to any one of claims 1 to 4, wherein in the light irradiation step, if the carotenoid compound is β-carotene, pulsed laser light having a central wavelength in the wavelength range of 450 nm to 600 nm is irradiated onto the suspension.

7. The cis-isomerization method according to any one of claims 1 to 4, wherein in the light irradiation step, if the carotenoid compound is astaxanthin, pulsed laser light having a central wavelength in the wavelength range of 450 nm to 650 nm is irradiated onto the suspension.

8. The cis-isomerization method according to any one of claims 1 to 4, wherein in the light irradiation step, if the carotenoid compound is lycopene, pulsed laser light having a central wavelength in the wavelength range of 500 nm to 620 nm is irradiated onto the suspension.

9. A method for producing food and beverages using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described in any one of claims 1 to 8 as a raw material.

10. A method for producing cosmetics using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described in any one of claims 1 to 8 as a raw material.

11. A method for producing a pharmaceutical product using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described in any one of claims 1 to 8 as a raw material.

12. A method for producing a supplement using a carotenoid compound that has been cis-isomerized by the cis-isomerization method described in any one of claims 1 to 8 as a raw material.

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