Lycopene microemulsion and preparation method thereof

Abstract

The invention relates to a lycopene microemulsion and a preparation method thereof. The preparation method of the lycopene micro-emulsion comprises the following steps: heating and stirring span and Tween until the span and Tween are milky white uniform emulsion; and adding lycopene oleoresin into the milk white uniform emulsion, heating and stirring until the materials are uniformly mixed, adding water, and continuously stirring until the materials are uniformly mixed to obtain the lycopene microemulsion. According to the lycopene micro-emulsion and the preparation method thereof, the content and the stability of lycopene in the water-dispersible lycopene micro-emulsion are greatly improved by adopting a micro-emulsification method, and the lycopene micro-emulsion is shaken up in water and then stands still, so that the layering phenomenon is avoided, and the lycopene plays a health-care role in more varieties.

Description

Technical Field

[0001] The invention belongs to the technical field of lycopene, and particularly relates to a lycopene microemulsion and a preparation method thereof. Background Art

[0002] As a major tomato-growing province, Xinjiang's tomato product exports account for about 25% of international trade. More than 90% of Xinjiang's total tomato product output is exported. Xinjiang's dependence on foreign trade is extremely high, and the market risks it faces are also high. Xinjiang's tomato products are mainly for the international market, first sent to coastal ports such as Tianjin, Shanghai, Shenzhen, and then exported. The transportation distance is about 4,000 km, and the transportation cost is more than 600 yuan per ton. For tomato products with low added value, this is a heavy burden, which will greatly reduce the cost competitiveness of Xinjiang's tomato products.

[0003] Lycopene is a tomato product with high added value. As a new functional natural pigment, it has broad development space. However, due to its strong hydrophobic structure, lycopene has very poor water solubility, which greatly limits its application range. Therefore, how to use physical means to treat lycopene so that it can be stably suspended in water, forming a similar "dissolved" effect and can be easily applied to water-based food systems has become a key issue in the production and consumption of lycopene.

[0004] Lycopene is mainly used in oily food systems or as an ingredient for soft capsule production. Existing methods for improving the water dispersibility of lycopene include: obtaining a protein complex of lycopene by enzymatic hydrolysis, a method of simple emulsification, dissolving lycopene in an organic solvent, emulsifying, and then evaporating the organic solvent, and a method of mixing lycopene, an emulsifier, and water and then homogenizing and emulsifying. However, the above methods all have the common defect that the lycopene in the product is easy to settle, the content of the target component in the water-dispersible lycopene microemulsion that can be stably suspended is too low (less than 0.1%), the cost of use is too high, and it is not suitable for actual production. Therefore, the key issue to broaden the application scope of lycopene is how to improve the solubility and stability of lycopene.

[0005] In view of this, the present invention provides a new lycopene microemulsion and a preparation method thereof through research on the preparation method of water-dispersible lycopene microemulsion, and prepares a water-dispersible lycopene microemulsion with high lycopene content, good color, high stability, easy use and meeting actual production needs. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing lycopene microemulsion, which effectively solves the strong hydrophobic effect of lycopene in water through microemulsification, so that lycopene can be stably dissolved in the aqueous solution.

[0007] In order to achieve the above purpose, the technical solution adopted is:

[0008] A method for preparing lycopene microemulsion comprises the following steps:

[0009] Heat and stir the Span and Tween until a milky white homogeneous emulsion is formed;

[0010] Add lycopene oleoresin to the milky white uniform emulsion, heat and stir until the mixture is uniformly mixed, then add water and continue stirring until the mixture is uniformly mixed to obtain the lycopene microemulsion.

[0011] Furthermore, the Span is Span-40 and the Tween is Tween-80.

[0012] Furthermore, the mass ratio of the Span, Tween, lycopene oleoresin and water is 1.0-1.4:6.5-7.1:1.8-2.2:10-14.

[0013] Furthermore, the mass ratio of the Span, Tween, lycopene oleoresin and water is 1.2:6.8:2.0:12.

[0014] Further, the Span and Tween are stirred at 20-80°C;

[0015] The lycopene oleoresin is added, stirred at 20-80°C until the mixture is uniformly mixed, and then water is added, and stirred at 20-80°C until the mixture is uniformly mixed.

[0016] Furthermore, the Span and Tween are stirred at 40°C;

[0017] The lycopene oleoresin is added, stirred at 40°C until the mixture is uniformly mixed, and then water is added, and stirred at 40°C until the mixture is uniformly mixed.

[0018] Furthermore, the Span and Tween are magnetically stirred at 300-500 r / min;

[0019] The lycopene oleoresin is added, magnetically stirred at 300-500 r / min until the mixture is uniformly mixed, and then water is added, and magnetically stirred at 300-500 r / min until the mixture is uniformly mixed.

[0020] Furthermore, the Span and Tween are magnetically stirred at 400 r / min;

[0021] The lycopene oleoresin is added, magnetically stirred at 400 r / min until the mixture is uniformly mixed, and then water is added, and magnetically stirred at 400 r / min until the mixture is uniformly mixed.

[0022] Another object of the present invention is to provide a lycopene microemulsion prepared by the above-mentioned preparation method. The water-dispersible lycopene microemulsion has a high lycopene content and strong stability. After being shaken in water and left to stand, no stratification occurs.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] Lycopene, as a fat-soluble carotenoid, has strong hydrophobicity, and thus has very low solubility in water and water-based foods, which severely limits the scope of use and effect of lycopene in food processing. How to solve the problem of lycopene's dissolution in water and water-based foods is of great significance and innovation. The technical solution of the present invention can effectively solve the strong hydrophobic effect of lycopene in water, and through microemulsification, lycopene can be stably dissolved in an aqueous solution, so that lycopene can play a health-care role in more varieties. For example: lycopene can be applied to beverages to prepare a new type of beverage with health-care functions. It can also be applied to other water-based foods or products, such as facial masks, cosmetics, foods, etc., to fully expand the application of lycopene. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the process flow chart of Example 1.

[0026] Figure 2 Effect of different light sources on the retention rate of lycopene in lycopene microemulsion.

[0027] Figure 3 Effects of different light sources on the retention rate of lycopene in lycopene microemulsion and lycopene powder. DETAILED DESCRIPTION

[0028] In order to further illustrate the lycopene microemulsion and its preparation method of the present invention and achieve the intended purpose of the invention, the lycopene microemulsion and its preparation method according to the present invention, its specific implementation, structure, characteristics and efficacy are described in detail below in combination with the preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0029] The following will further introduce the lycopene microemulsion and the preparation method thereof in detail in conjunction with specific embodiments:

[0030] As a new functional natural pigment, lycopene has broad development potential. However, due to its strong hydrophobic structure, its water solubility is very poor, which greatly limits its application scope.

[0031] Microemulsion is a transparent dispersion system. Microemulsion was first proposed in 1943 and is defined as: a thermodynamically stable, isotropic, transparent homogeneous dispersion system formed by two immiscible liquids under the action of the surfactant interfacial film. Microemulsion has the characteristics of large and uniform dispersion; it is a thermodynamically stable system; large solubilization capacity; ultra-low interfacial tension; high fluidity and low viscosity.

[0032] The microemulsion obtained by microemulsion technology is a thermodynamically stable, translucent to transparent, isotropic oil-water mixed system, in which the surfactant and co-surfactant play a stabilizing role. The particle size of the microemulsion is between 1-100nm. Microemulsion can be divided into three structures: oil-in-water type (O / W), oil-water bicontinuous type (BC), and oil-in-water type (W / O). Compared with ordinary emulsions, microemulsions have the following advantages:

[0033] (1) Microemulsions are formed spontaneously without the help of external forces, while ordinary emulsions need to be processed by homogenization, ultrasonic stirring, etc. to form.

[0034] (2) Microemulsions do not experience the aggregation and stratification phenomena that occur in ordinary emulsions and are thermodynamically stable systems.

[0035] (3) Because it is a thermodynamically stable system, the preparation method of microemulsion is relatively simple;

[0036] (4) Because it is optically transparent, any inhomogeneity or precipitate can be easily detected

[0037] (5) Can be stored for a long time without stratification

[0038] (6) Microemulsion has good solubilizing effect and can produce products with higher oil content;

[0039] (7) Microemulsion particles are small and can diffuse and penetrate into the skin more easily, thereby increasing the utilization rate of active ingredients.

[0040] The present invention selects and utilizes oil, emulsifier and co-emulsifier in microemulsion, utilizes reasonable microemulsion formula, and utilizes microemulsion technology to emulsify the fat-soluble functional ingredient lycopene into a transparent water-dispersible lycopene microemulsion with good water solubility and strong stability. The diameter of the microemulsified lycopene nano solution is below 100nm, and it is dark red, clear and transparent. The lycopene microemulsion can be mutually soluble in water at a large volume ratio, and the solution is also clear and transparent. The technical scheme of the present invention is:

[0041] A method for preparing lycopene microemulsion comprises the following steps:

[0042] Heat and stir the Span and Tween until a milky white homogeneous emulsion is formed;

[0043] Add lycopene oleoresin to the milky white uniform emulsion, heat and stir until the mixture is uniformly mixed, then add water and continue stirring until the mixture is uniformly mixed to obtain the lycopene microemulsion.

[0044] Preferably, the Span is Span-40 and the Tween is Tween-80.

[0045] In the above technical scheme, Tween-80 is selected as an emulsifier. In actual production and utilization, non-ionic surfactants are usually used, and considering factors such as toxicity and price, Tween and Span are currently the most widely used non-ionic surfactants. In order to achieve a better microemulsion effect, the HLB value of the surfactant should be close to the HLB value of the emulsified drug. The HLB value range of the Span series is about 1.8-8.6, and the HLB of the Tween series surfactants is between 13-17. Since the present invention is to prepare an O / W type microemulsion system, the Tween series with a larger HLB value and better water solubility is selected as an emulsifier. The choice of emulsifier has a certain influence on the lycopene microemulsion system. At room temperature, Tween-80 has the best stability.

[0046] Preferably, the mass ratio of the Span, Tween, lycopene oleoresin and water is 1.0-1.4:6.5-7.1:1.8-2.2:10-14.

[0047] Further preferably, the mass ratio of the Span, Tween, lycopene oleoresin and water is 1.2:6.8:2.0:12.

[0048] Preferably, the Span and Tween are stirred at 20-80°C;

[0049] The lycopene oleoresin is added, stirred at 20-80°C until the mixture is uniformly mixed, and then water is added, and stirred at 20-80°C until the mixture is uniformly mixed.

[0050] Further preferably, the Span and Tween are stirred at 40°C;

[0051] The lycopene oleoresin is added, stirred at 40°C until the mixture is uniformly mixed, and then water is added, and stirred at 40°C until the mixture is uniformly mixed.

[0052] Preferably, the Span and Tween are magnetically stirred at 300-500 r / min;

[0053] The lycopene oleoresin is added, magnetically stirred at 300-500 r / min until the mixture is uniformly mixed, and then water is added, and magnetically stirred at 300-500 r / min until the mixture is uniformly mixed.

[0054] Further preferably, the Span and Tween are magnetically stirred at 400 r / min;

[0055] The lycopene oleoresin is added, magnetically stirred at 400 r / min until the mixture is uniformly mixed, and then water is added, and magnetically stirred at 400 r / min until the mixture is uniformly mixed.

[0056] Example 1.

[0057] Combination Figure 1 , the specific steps are as follows:

[0058] (1) Pour 1.2 g of ground Span-40 into a beaker, add 6.8 g of Tween-80, heat in a 40°C water bath, and stir with a magnetic stirrer at 400 rpm until the sample becomes a milky white uniform emulsion.

[0059] (2) Add 2.0 g of lycopene oleoresin (with a lycopene content of 6%), heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform. Add 12 ml of water, heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform, and a 0.5% lycopene microemulsion product is obtained.

[0060] (3) A freeze-thaw test was performed on the prepared 0.5% microemulsion product.

[0061] Method: Take 10 mL of the lycopene microemulsion prepared in step (2), seal and place at -25°C and 40°C for 24 hours respectively, cycle three times, and then observe whether the lycopene microemulsion shows stratification and turbidity at room temperature.

[0062] Results: As shown in Table 1, the lycopene microemulsion did not stratify in each freeze-thaw cycle. The results show that the lycopene microemulsion did not stratify under freeze-thaw conditions and was in a uniform state.

[0063] Table 1 Cyclic freeze-thaw results

[0064]

[0065] (4) A light test was conducted on the prepared 0.5% microemulsion product.

[0066] Method: Take 3 portions of 50 mL of the lycopene microemulsion prepared in step (2) and 10 mg of lycopene powder, place them in a container, take 1 portion of the lycopene microemulsion and 1 portion of the lycopene powder, place them in a dark place in a room at room temperature and light-proof, under light and ultraviolet light, place them for 60 hours, take samples every 12 hours, calculate the lycopene retention rate in the samples, and repeat 3 times. At the same time, compare the lycopene retention rates of the lycopene microemulsion and lycopene powder under different light conditions. The lycopene retention rate calculation formula is as follows:

[0067] Lycopene retention (%) = (lycopene content of the product after storage for a period of time / lycopene content of the product before storage) × 100%

[0068] Results: The lycopene microemulsion was placed under different light sources for 60 hours, and samples were taken every 12 hours to calculate the lycopene retention rate. Figure 2 It can be seen that as time goes by, the retention rate of lycopene in lycopene microemulsion under different light conditions gradually decreases, and the UV light group decreases the fastest. After 60 hours of UV light exposure, the retention rate of lycopene is 77.02%; followed by the light group, after 60 hours of storage, the retention rate of lycopene is 87.89%; while the change trend of the indoor light-proof group is relatively slow. After 60 hours of storage, the retention rate of lycopene reaches 97.21%, which is almost unaffected. Therefore, it can be seen that lycopene microemulsion should be protected from light, especially ultraviolet light, during storage.

[0069] The lycopene retention rates of lycopene microemulsion and lycopene powder were calculated after they were placed under different light sources for 60 hours. Figure 3 It can be seen that under different light sources, the retention rates of lycopene in lycopene microemulsion and lycopene powder decreased significantly, but the retention rate of lycopene powder was lower than that of lycopene microemulsion, showing a significant difference (P < 0.05), indicating that the retention rate of lycopene can be improved to a certain extent after making lycopene liquid.

[0070] (5) A storage test was conducted on the prepared 0.5% microemulsion product.

[0071] Method: 100 mL of the lycopene microemulsion prepared in step (2) was placed in a brown sample and stored in a sealed container at room temperature and away from light for 10 weeks. The lycopene microemulsion was observed every 2 weeks to determine whether stratification occurred, so as to investigate its stability under long-term storage.

[0072] Results: The storage stability of the lycopene microemulsion system can be observed most intuitively and simply by storing the sample in a sealed container at room temperature and away from light for 10 weeks and observing and recording every 2 weeks to see whether the lycopene microemulsion is stratified. The research results are shown in Table 2. After 10 weeks of long-term storage, the lycopene microemulsion did not stratify over time. The results show that the lycopene microemulsion prepared by the above method has good storage stability.

[0073] Table 2 Results of sealing and standing at room temperature and away from light

[0074]

[0075] It can be seen from experiments (3)-(5) that the lycopene microemulsion prepared by the technical solution of the present invention has strong stability.

[0076] Example 2.

[0077] The operation steps of Example 2 are the same as those of Example 1, except for the temperature of the water bath heating in steps (1)-(2).

[0078] Generally, microemulsions will become turbid at high temperatures or crystallize at low temperatures, so the effect of temperature on the microemulsion system should be considered. In this example, 20°C, 40°C, 50°C, 60°C and 80°C were selected as the preparation temperatures for preparing lycopene microemulsions, and the preparation conditions of lycopene at the five temperatures were observed. The preparation temperature has an effect on the lycopene microemulsion system. The specific temperatures and results are shown in Table 3.

[0079] Table 3

[0080]

[0081]

[0082] The particle size and distribution of microemulsion are important parameters for characterizing the shape of microemulsion. The PDI value can be measured to understand the distribution range of microemulsion particle size. The smaller the PDI value, the better the uniformity of the formed microemulsion. A stable microemulsion dispersion system requires a PDI less than 0.3. Combined with Table 3, when the preparation temperature is between 40-60°C, the PDI is less than 0.3; when the preparation temperature is between 40°C, the microemulsion system is optimal.

[0083] Example 3.

[0084] The operation steps of Example 3 are the same as those of Example 1, except that the speed of magnetic stirring in steps (1)-(2) is used. The specific speed and results are shown in Table 4.

[0085] Table 4

[0086]

[0087] The high-speed operation of the emulsification equipment can fully mix the oil phase and the water phase of the material in the emulsification tank. The higher the stirring speed, the corresponding improvement in production efficiency. The stirring speed of many traditional emulsification equipment is too low, and the water and oil phases in the emulsification tank cannot be fully mixed. The general finished product stability is very poor, and the quality is not very good. Only some low-end products with simple processes can be made. If the stirring speed of the emulsification equipment is too high, the air will be stirred to form bubbles and brought into the system, making it a three-phase system, which makes the cosmetic emulsion unstable. Combined with Table 4, it can be seen that when the stirring speed is 400r / min, the microemulsion system is relatively stable.

[0088] Example 4.

[0089] The operation steps of Example 4 are the same as those of Example 1, except that microemulsion products with different lycopene contents are prepared. The specific lycopene contents and results are shown in Table 5.

[0090] Table 5

[0091]

[0092] It can be seen from Table 3 that when the lycopene content in the microemulsion product is too high, the viscosity is too high and the fluidity is poor. Therefore, under the premise of ensuring the stability, water solubility and mobile phase of the microemulsion product, the lycopene content in the microemulsion product is preferably 0.5%.

[0093] Example 5.

[0094] The specific steps are as follows:

[0095] (1) Pour 1.0 g of ground Span-40 into a beaker, add 6.5 g of Tween-80, heat in a 40°C water bath, and stir with a magnetic stirrer at 400 rpm until the sample becomes a milky white uniform emulsion.

[0096] (2) Add 1.8 g of lycopene oleoresin (with a lycopene content of 6%), heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform. Continue to add 10 ml of water, heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform, and a microemulsion product is obtained.

[0097] Example 6.

[0098] The specific steps are as follows:

[0099] (1) Pour 1.4 g of ground Span-40 into a beaker, add 7.1 g of Tween-80, heat in a 40°C water bath, and stir with a magnetic stirrer at 400 rpm until the sample becomes a milky white uniform emulsion.

[0100] (2) Add 2.2 g of lycopene oleoresin (with a lycopene content of 5%), heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform. Continue to add 14 ml of water, heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform, and a microemulsion product is obtained.

[0101] Example 7.

[0102] The specific steps are as follows:

[0103] (1) Pour 1.1 g of ground Span-40 into a beaker, add 6.7 g of Tween-80, heat in a 40°C water bath, and stir with a magnetic stirrer at 400 rpm until the sample becomes a milky white uniform emulsion.

[0104] (2) Add 1.9 g of lycopene oleoresin (with a lycopene content of 6%), heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform. Add 11 ml of water, heat in a water bath at 40° C., and stir with a magnetic force at 400 r / min until the sample is uniform. Then, a microemulsion product is obtained.

[0105] The above is only a preferred embodiment of the embodiment of the present invention, and does not impose any form of limitation on the embodiment of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiment based on the technical essence of the embodiment of the present invention are still within the scope of the technical solution of the embodiment of the present invention.

Claims

1. A method for preparing lycopene microemulsion, characterized in that: The following steps are involved: Heat and stir the Span and Tween until a milky white homogeneous emulsion is formed; Add lycopene oleoresin to the milky white uniform emulsion, heat and stir until the mixture is uniformly mixed, then add water and continue stirring until the mixture is uniformly mixed to obtain the lycopene microemulsion.

2. The preparation method according to claim 1, characterized in that: The Span is Span-40 and the Tween is Tween-80.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the Span, Tween, lycopene oleoresin and water is 1.0-1.4:6.5-7.1:1.8-2.2:10-14.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the Span, Tween, lycopene oleoresin and water is 1.2:6.8:2.0:

12.

5. The preparation method according to claim 1, characterized in that: The Span and Tween are stirred at 20-80°C; The lycopene oleoresin is added, stirred at 20-80°C until the mixture is uniformly mixed, and then water is added, and stirred at 20-80°C until the mixture is uniformly mixed.

6. The preparation method according to claim 5, characterized in that: The Span and Tween are stirred at 40°C; The lycopene oleoresin is added, stirred at 40°C until the mixture is uniformly mixed, and then water is added, and stirred at 40°C until the mixture is uniformly mixed.

7. The preparation method according to claim 1, characterized in that: The Span and Tween are magnetically stirred at 300-500 r / min; The lycopene oleoresin is added, magnetically stirred at 300-500 r / min until the mixture is uniformly mixed, and then water is added, and magnetically stirred at 300-500 r / min until the mixture is uniformly mixed.

8. The preparation method according to claim 7, characterized in that: The Span and Tween are magnetically stirred at 400 r / min; The lycopene oleoresin is added, magnetically stirred at 400 r / min until the mixture is uniformly mixed, and then water is added, and magnetically stirred at 400 r / min until the mixture is uniformly mixed.

9. A lycopene microemulsion, characterized in that: The preparation method is described in any one of claims 1 to 8.

Images