Efficient and stable lycopene isomerization method
By leveraging the synergistic effect of confined water and transition metal-based catalysts, the presence state of water molecules is regulated, thereby improving the efficiency and product retention rate of the lycopene isomerization reaction. This solves the problem of insufficient efficiency and retention rate in existing technologies and achieves efficient and stable lycopene isomerization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PHARM UNIV
- Filing Date
- 2025-11-28
- Publication Date
- 2026-05-01
AI Technical Summary
In existing technologies, the isomerization reaction of lycopene is inefficient and the product retention rate is insufficient. In particular, it is difficult to improve the yield and retention rate of cis isomers at the same time, and the use of organic solvents leads to the degradation of lycopene.
A catalytic system was formed using confined water and a transition metal-based catalyst. By adding confined water molecules to an organic solvent and using Cu-MOF-801 nanomaterials as a catalyst, the presence state of water molecules was controlled, promoting the isomerization reaction of lycopene and forming the isomerization intermediate lycopene radical, thereby improving the isomerization efficiency and retention rate of cis-lycopene.
The efficiency of cis-lycopene isomerization was improved to 82.2%, and the retention rate reached 90.3%, which is far higher than the existing technology. This solved the problems of reaction efficiency and product retention rate, and is suitable for the later application of lycopene.
Smart Images
Figure CN121949050A_ABST
Abstract
Description
A highly efficient and stable method for lycopene isomerization Technical Field
[0001] This invention relates to a highly efficient and stable method for lycopene isomerization. Background Technology
[0002] The chemical configuration of lycopene directly affects its absorption efficiency and physiological function in vivo, with the cis isomer exhibiting superior bioavailability and activity compared to the all-trans structure. Therefore, constructing a catalytic system capable of achieving efficient and highly selective cis isomerization of lycopene under mild conditions has become an important research direction in this field.
[0003] In existing technologies, heterogeneous catalysts such as I-TiO2 and Cu-MCM-41 are used for the isomerization reaction of lycopene, but this usually requires pure organic solvents such as dichloromethane and acetone. These systems not only have low reaction rates and limited product yields (e.g., approximately 50% yield after 6 hours), but the organic solvents also induce lycopene degradation, leading to product loss, with degradation rates reaching up to 30%. To improve reaction efficiency, recent studies have attempted to introduce a small amount of free water into the organic medium, utilizing water molecules to lower the reaction energy barrier and thus improve isomerization efficiency. For example, adding 2.5% water to an acetone system catalyzed by FeCl3 or AlCl3 can increase the total cis-lycopene yield to five times. Furthermore, the Fe2(SO4)3–free water composite catalytic system forms [Fe(H2O)6]... 3+ Hydrated ions reconstruct the hydrogen bond network and enhance the electronic coupling between metal ions and the lycopene π system, increasing the cis-isomerization efficiency to 65%. However, the coordination stability of hydrated ions in this system is insufficient, and lycopene self-aggregates due to hydrophobic interactions, forming a layered structure that hinders effective mass transfer, resulting in a final product retention rate of only 52%. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide a highly selective, efficient and stable method for lycopene isomerization.
[0005] Technical solution: This invention discloses a highly efficient and stable method for lycopene isomerization. Trans-lycopene is dissolved in an organic solvent, and a transition metal-based catalyst and a catalytic medium are added to form a catalytic system. The system is then heated and stirred in the dark to efficiently catalyze the isomerization of lycopene.
[0006] The catalytic medium is confined water, which is water molecules bound in the cavities and channels of the porous structure of Cu-MOF-801. The water molecules are confined in molecular or nanoscale space to form a confinement effect. The volume percentage of the confined water in the catalytic system is 1-2%.
[0007] The preparation method of the bimetallic catalyst includes the following steps:
[0008] (1) Dissolve trans-lycopene in acetone, add a transition metal catalyst to the reaction system, and add a catalytic medium to the reaction system to form a catalytic system. Due to the confinement effect of the synthesized transition metal-based catalyst, water molecules can be precisely controlled through coordination. The water molecules in the catalytic medium are in the form of confined water molecules.
[0009] (2) The above catalytic system was subjected to a water bath and heated with stirring;
[0010] (3) After the catalysis is completed, the solution is centrifuged and the catalyst precipitate is recovered to obtain cis-lycopene acetone solution, thus completing the isomerization of lycopene.
[0011] In step (1), the concentration of the transition metal-based catalyst is 0.5 mg / mL.
[0012] In step (2), the heating temperature is 30-40℃ and the stirring time is 1 h.
[0013] The transition metal-based catalyst is a bimetallic organic framework material.
[0014] The bimetallic organic framework material is a Cu-doped MOF-801 nanomaterial.
[0015] The bimetallic catalyst is prepared by dissolving fumaric acid, zirconium oxychloride octahydrate and copper nitrate trihydrate in a mixed solution of DMF and formic acid, stirring thoroughly to obtain a mixed solution; reacting the mixed solution at high temperature, cooling and washing at room temperature after the reaction is completed to obtain a precipitate; and drying the precipitate under vacuum.
[0016] The molar mass of fumaric acid was 4-6 mmol, the molar mass of zirconium oxychloride octahydrate was 3.54 mmol, the molar mass of copper nitrate trihydrate was 1-5 mmol, and the volume ratio of DMF to formic acid was (18-20 mL: 5-8 mL). The reaction was carried out at a high temperature of 120-130℃ for 5-6 h. The drying temperature was 50-60℃ for 7-8 h, and the vacuum drying pressure was -0.1 MPa.
[0017] The specific method for preparing the transition metal-based catalyst is as follows:
[0018] (1) 5 mmol of fumaric acid, 3.75 mmol of zirconium oxychloride octahydrate and 1.25 mmol of copper nitrate trihydrate were dissolved in a mixture of 20 mL of DMF and 7 mL of formic acid, and the mixture was stirred thoroughly.
[0019] (2) Transfer the above mixed solution to a high-pressure reactor and place it in an oven (130℃, 6 h). After the reaction is complete, cool it to room temperature. Then wash it four times by centrifugation with DMF and methanol.
[0020] (3) After washing, the precipitate is placed in a vacuum drying oven and dried (50℃, 8 h). The vacuum pump is turned on to evacuate and dry to a pressure of -0.1 MPa to obtain the transition metal-based catalyst.
[0021] Invention Principle: The present invention provides a highly efficient and stable lycopene isomerization method that employs a transition metal-confined water synergistic catalysis for lycopene isomerization. By controlling the presence of water molecules through a transition metal-based catalyst, free water is transformed into nano-confined water. This confined water acts as an electron transfer medium in the trans-lycopene isomerization pathway, accelerating the loss of electrons by trans-lycopene and forming the isomerization intermediate lycopene radical, thereby increasing the yield of cis-lycopene isomerization. Research indicates a competitive relationship between electronic effects and mass transfer constraints in the catalytic process: the metal-water interface promotes π-electron rearrangement, which is beneficial for the isomerization reaction. By controlling the presence of water molecules in the reaction environment, the problem of aggregation behavior caused by free water severely restricting the efficiency of reactant transport at the catalytic interface is overcome. This optimizes the reaction pathway and breaks through the bottleneck of balancing efficiency and selectivity in existing technologies, providing a new approach for achieving highly efficient cis-isomerization of lycopene.
[0022] Furthermore, optimizing the catalyst concentration and catalytic time further improved the isomerization efficiency and retention rate of lycopene. Excessively high and long catalyst concentrations and catalytic times may increase the degradation rate of lycopene, while excessively low and short catalyst concentrations and catalytic times cannot achieve trans-lycopene isomerization. Therefore, under the condition of confined water molecules as a mediator to enhance efficiency, multiple conditions are matched with each other, and the content of catalytic medium, catalyst concentration and catalytic time are optimized to achieve synergistic effects and achieve the best lycopene isomerization effect.
[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The efficient and stable lycopene isomerization method of the present invention can improve the isomerization efficiency of cis-lycopene to 82.2%, which is much higher than the thermal isomerization efficiency of 37.6% of the prior art; and under the process conditions, lycopene has a higher retention rate (90.3%), which is beneficial to its later application in lycopene. Attached Figure Description
[0024] Figure 1 is a liquid phase diagram of the catalytic content of trans-lycopene;
[0025] Figure 2 shows the isomerization rate and retention rate of catalytic trans-lycopene solution with varying catalytic media content.
[0026] Figure 3 shows the liquid phase diagram of catalytic trans-lycopene at different material concentrations;
[0027] Figure 4 shows the isomerization rate and retention rate of trans-lycopene catalyzed with different material concentrations;
[0028] Figure 5 shows the liquid phase diagram of trans-lycopene at different catalytic times;
[0029] Figure 6 shows the isomerization rate and retention rate of trans-lycopene catalyzed with different material concentrations;
[0030] Figure 7 shows SEM images of different cis-lycopene contents;
[0031] Figure 8 shows XRD electron micrographs of different cis-lycopene contents;
[0032] Figure 9 is an in-situ temperature-variable X-ray diffraction pattern of water molecules bound to the catalyst. Detailed Implementation
[0033] The technical solution of the present invention will be further described below with reference to the embodiments. The test materials used in the embodiments can all be purchased through conventional means.
[0034] Example 1
[0035] The efficient and stable lycopene isomerization method of the present invention, which involves adding 1% confined water to the catalytic system, specifically includes the following steps:
[0036] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 10 mg of transition metal-based catalyst and add it to the reaction system. The catalyst concentration is 0.5 mg / mL. Further add 200 μL of confined water to the reaction system to form a catalytic system.
[0037] (2) Transfer the above catalytic system to a 37°C water bath and stir magnetically at 600 rpm / min for 1 h.
[0038] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. A cis-lycopene acetone solution was obtained and stored at 4°C protected from light for liquid chromatography analysis.
[0039] Example 2
[0040] Compared with Example 1, the highly efficient and stable lycopene isomerization method of the present invention, which adds 2% confined water to the catalytic system, specifically includes the following steps:
[0041] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 10 mg of transition metal-based catalyst and add it to the reaction system. The catalyst concentration is 0.5 mg / mL. Further add 400 μL of confined water to the reaction system to form a catalytic system.
[0042] (2) Transfer the above catalytic system to a 37°C water bath and stir magnetically at 600 rpm / min for 1 h.
[0043] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0044] Comparative Example 1
[0045] Compared to Example 1, the water molecule content of Comparative Example 1 was 0%.
[0046] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 10 mg of transition metal-based catalyst and add it to the reaction system.
[0047] (2) Transfer the above reaction system to a 37°C water bath, stir magnetically at 600 rpm / min, and catalyze for 1 h.
[0048] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0049] Comparative Example 2
[0050] Compared to Example 1, Comparative Example 2 has a water molecule content of 5%.
[0051] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 10 mg of transition metal-based catalyst and add it to the reaction system. Further add 1000 μL of water to the reaction system to form a catalytic system.
[0052] (2) Transfer the above catalytic system to a 37°C water bath, stir magnetically at 600 rpm / min, and catalyze for 1 h.
[0053] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0054] As shown in Figures 1 and 2, when 1% and 2% of confined water molecules were added to the catalytic system, the proportion of cis-lycopene increased from 34.9% (in anhydrous system) to 72.9% and 82.2%, respectively, with retention rates of 93.6% and 90.3%. However, as the water molecule concentration increased to 5%, the lycopene retention rate dropped to only 32%. Therefore, adding 1% and 2% confined water molecules to the catalytic system is more conducive to the isomerization of trans-lycopene, especially with 2% confined water, the isomerization effect is optimal.
[0055] In-situ variable-temperature X-ray diffraction analysis confirmed the morphology of "confined water." As shown in Figure 9, the XRD pattern of Cu-MOF-801 changed significantly after water absorption (e.g., new peaks appeared at 2θ = 13.1° and 17.3°, while characteristic peaks disappeared at 22.1° and 24.5°), indicating that water molecules coordinated with Cu²⁺, leading to local crystal structure reconstruction. This demonstrates that in Cu-MOF-801, water molecules exist in a "confined state" form that specifically binds to metal sites.
[0056] Comparative Example 3
[0057] Compared to Example 1, the concentration of the transition metal-based catalyst was changed, and the concentration of the transition metal-based catalyst in Comparative Example 3 was 0 mg / mL.
[0058] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Add 200 μL of confined water to the reaction system to form a catalytic system.
[0059] (2) Transfer the above catalytic system to a 37°C water bath, stir magnetically at 600 rpm / min, and catalyze for 1 h.
[0060] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0061] Comparative Example 4
[0062] Compared with Example 1, the concentration of the transition metal-based catalyst was changed, and the concentration of the transition metal-based catalyst in Comparative Example 3 was 0.1 mg / mL.
[0063] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 2 mg of transition metal-based catalyst and add it to the reaction system. Further add 200 μL of confined water to the reaction system to form a catalytic system.
[0064] (2) Transfer the above catalytic system to a 37°C water bath, stir magnetically at 600 rpm / min, and catalyze for 1 h.
[0065] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0066] Comparative Example 5
[0067] Compared to Example 1, the concentration of the transition metal-based catalyst was changed, and the concentration of the transition metal-based catalyst in Comparative Example 3 was 1 mg / mL.
[0068] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 20 mg of transition metal-based catalyst and add it to the reaction system. Further add 200 μL of confined water to the reaction system to form a catalytic system.
[0069] (2) Transfer the above catalytic system to a 37°C water bath, stir magnetically at 600 rpm / min, and catalyze for 1 h.
[0070] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0071] Comparative Example 6
[0072] Compared to Example 1, the catalytic time was changed, and the catalytic time of Comparative Example 4 was 2 h.
[0073] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 10 mg of transition metal-based catalyst and add it to the reaction system. Further add 200 μL of confined water to the reaction system to form a catalytic system.
[0074] (2) Transfer the above catalytic system to a 37°C water bath and stir magnetically at 600 rpm / min for 2 hours.
[0075] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0076] Comparative Example 7
[0077] Compared with Example 1, the catalytic time was changed, and the catalytic time of Comparative Example 4 was 0.5 h.
[0078] (1) Weigh 10 mg of trans-lycopene and dissolve it in 20 mL of acetone solution. Weigh 10 mg of transition metal-based catalyst and add it to the reaction system. Further add 200 μL of confined water to the reaction system to form a catalytic system.
[0079] (2) Transfer the above catalytic system to a 37°C water bath, stir magnetically at 600 rpm / min, and catalyze for 0.5 h.
[0080] (3) After catalysis, the solution was centrifuged at 8000 rpm / min to recover the catalyst precipitate. The cis-lycopene acetone solution was obtained and stored at 4°C in the dark for liquid chromatography analysis.
[0081] As shown in Figures 3 and 4, the isomerization rate was 37.5% and the retention rate was 96.2% when the catalyst concentration was 0.1 mg / mL, and 82.2% and 90.3% when the catalyst concentration was 0.5 mg / mL. However, when the catalyst concentration was increased to 1 mg / mL, the isomerization rate of cis-lycopene was only 77.2%, and the lycopene retention rate decreased to 25.2%. Therefore, the isomerization effect was optimal when the catalyst concentration was 0.5 mg / mL.
[0082] As shown in Figures 5 and 6, the isomerization rate was 22.9% and the retention rate was 96.9% when the catalytic time was 0.5 h; the isomerization rate was 82.2% and the retention rate was 90.3% when the catalytic time was 1 h; when the catalytic time was extended to 2 h, the isomerization rate of cis-lycopene was 63.1%, but the retention rate decreased to 22.2%. Therefore, the isomerization effect was optimal when the catalytic time was 1 h.
[0083] SEM electron microscopy analysis of different cis-lycopene contents:
[0084] (1) Select the standard trans-lycopene, the product lycopene (37.5-Z) in Comparative Example 4, the product lycopene (77.2%-Z) in Comparative Example 5, and the product lycopene (82.2%-Z) in Example 2 from the above experiment and drop them onto the silicon wafer and dry them at 15°.
[0085] (2) Further use scanning electron microscopy to observe the micromorphology of lycopene with different cis contents.
[0086] As shown in Figure 7, trans-lycopene forms plate-like crystals, while as the proportion of cis-lycopene in the catalytic system gradually increases, lycopene becomes less likely to crystallize and turns into an amorphous form.
[0087] XRD detection of different cis-lycopene contents:
[0088] (1) Select the standard trans-lycopene, the product lycopene (37.5%-Z) in Comparative Example 3, the product lycopene (77.2%-Z) in Comparative Example 7, and the product lycopene (82.2%-Z) in Example 1 from the above experiments and obtain powder by rotary evaporation at 4°.
[0089] (2) Further X-ray diffraction (XRD) was used to analyze the crystal structure of lycopene with different cis contents.
[0090] As shown in Figure 8, trans-lycopene has a crystalline form, while the crystallinity of lycopene gradually decreases as the proportion of cis-lycopene in the catalytic system gradually increases. This is attributed to the fact that when the content of the Z-isomer increases, it generates huge steric hindrance, thereby reducing the potential attractive π-π force, which leads to a decrease in crystallinity.
[0091] Therefore, the efficient and stable lycopene isomerization method of the present invention improves the isomerization efficiency and retention rate of trans-lycopene by controlling the form of water molecules in the catalytic medium, selecting specific catalysts, and adjusting the catalytic concentration and catalytic time of the catalysts, and has great application prospects.
Claims
1. A highly efficient and stable method for lycopene isomerization, characterized in that, The method involves dissolving trans-lycopene in an organic solvent, adding a transition metal-based catalyst, then adding a catalytic medium to form a catalytic system. The system is then heated and stirred in the dark to efficiently catalyze the isomerization of lycopene.
2. The method according to claim 1, characterized in that, The catalytic medium is confined water, and the volume percentage of the catalytic medium in the catalytic system is 1-2%.
3. The method according to claim 1, characterized in that, Specifically, the following steps are included: (1) Dissolve trans-lycopene in acetone solution, add transition metal-based catalyst to reaction system, add catalytic medium to reaction system to form catalytic system; (2) Heat and stir the above catalytic system in water bath; (3) Centrifuge the solution after catalysis, recover the catalyst precipitate, and obtain cis-lycopene acetone solution, thus completing the isomerization of lycopene.
4. The method according to claim 3, characterized in that, In step (1), the concentration of the transition metal-based catalyst is 0.1-2 mg / mL.
5. The method according to claim 3, characterized in that, In step (2), the heating temperature is 30-40℃.
6. The method according to claim 1, characterized in that, The transition metal-based catalyst is a bimetallic organic framework material.
7. The method according to claim 6, characterized in that, The bimetallic organic framework material is a Cu-doped MOF-801 transition metal-based nanomaterial.
8. The method according to claim 6, characterized in that, The transition metal-based catalyst is prepared as follows: fumaric acid, zirconium oxychloride octahydrate and copper nitrate trihydrate are dissolved in a mixed solution of DMF and formic acid, and the mixture is stirred thoroughly to obtain a mixed solution; the mixed solution is reacted at high temperature, and after the reaction is completed, it is cooled and washed at room temperature to obtain a precipitate; the precipitate is then dried under vacuum to obtain the final product.
9. The method according to claim 8, characterized in that, The reaction at high temperature is 120~130℃ for 5~6 h; the drying temperature is 50~60℃ for 7~8 h.