Beta-carotene-polyphenol eutectic microcapsule and preparation method thereof

Abstract

The invention provides a beta-carotene-polyphenol eutectic microcapsule and a preparation method thereof, and belongs to the technical field of food processing. The preparation method comprises the following steps: mixing beta-carotene crystals and polyphenol, carrying out supercritical CO2 reaction to obtain beta-carotene-polyphenol eutectic crystals, dispersing the beta-carotene-polyphenol eutectic crystals in a protective colloidal solution, shearing, and grinding obtained beta-carotene crude dispersion liquid to obtain beta-carotene nano dispersion liquid; and drying the beta-carotene nano dispersed material liquid, so as to obtain the beta-carotene-polyphenol eutectic microcapsule. The preparation method comprises the following steps: firstly, preparing beta-carotene-polyphenol eutectic through a supercritical CO2 fluid technology so as to reduce the strong hydrophobicity of beta-carotene and further improve the loading capacity of beta-carotene, shearing the beta-carotene-polyphenol eutectic and protective colloid, grinding the obtained beta-carotene coarse dispersion liquid, and preparing the beta-carotene-polyphenol co-crystal capsule. And drying is carried out, such that the beta-carotene-polyphenol eutectic microcapsule is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and in particular to a beta-carotene-polyphenol eutectic microcapsule and a preparation method and application thereof. Background Art

[0002] β-carotene is a natural functional food ingredient with health benefits such as eye protection, antioxidant properties, and relief of cardiovascular and cerebrovascular diseases. However, its application is significantly limited by its high hydrophobicity, low oral bioavailability, and slow intestinal absorption. Furthermore, β-carotene is extremely unstable under conditions such as light, heat, and oxygen, and can undergo isomerization and oxidative degradation. Therefore, encapsulation is necessary to address these issues.

[0003] Nanoencapsulation is an effective solution to these issues with β-carotene. Using a single or composite wall material to encapsulate β-carotene at the nanoscale increases its water solubility while also enhancing its physical and chemical stability. Furthermore, nanoparticles can penetrate capillaries and enter the small intestinal epithelial cells, thereby improving β-carotene's targeting and bioavailability. However, nanoencapsulation encompasses a wide range of topics and methods, making it particularly important to identify suitable nanoencapsulation methods for β-carotene in the food industry.

[0004] Previously, solvent and oil dissolution methods were used to prepare low-loading (1-5 wt%) β-carotene microcapsule powders. These methods require the use of organic solvents or solubilizing oils to dissolve the β-carotene, and involve processes such as high-temperature oil dissolution, reagent desolventization, and residual content detection. This leads to negative issues such as large re-dissolved microcapsule particle size, a high proportion of β-carotene cis-isomers, and a cumbersome production process. In recent years, wet grinding processes have emerged to prepare β-carotene microcapsule preparations with loadings of 10 wt% or even higher. These processes involve adding β-carotene to a system containing a protective wall material, an antioxidant, a surfactant, and water, followed by direct mixing and grinding. The production process does not involve high-temperature treatment or the addition of organic solvents or solubilizing oils, offering advantages such as convenience, safety, environmental friendliness, and economy. However, the grinding process is long and inefficient, leading to oxidative degradation and cis-isomerization of the β-carotene during the grinding process, making it unfavorable for the production of high-loading β-carotene-polyphenol cocrystal microcapsules. Summary of the Invention

[0005] In light of this, the present invention aims to provide β-carotene-polyphenol cocrystal microcapsules and a method for preparing the same. The method utilizes supercritical CO2 fluid technology to prepare β-carotene-polyphenol cocrystals, reducing the strong hydrophobicity of β-carotene and preventing oxidative degradation and cis-isomerization of β-carotene.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing β-carotene-polyphenol cocrystal microcapsules, comprising the following steps:

[0008] β-carotene crystals and polyphenols are mixed and subjected to supercritical CO2 reaction to obtain β-carotene-polyphenol cocrystals;

[0009] dispersing the β-carotene-polyphenol co-crystal in a protective colloid solution, and then shearing the solution to obtain a β-carotene coarse dispersion;

[0010] grinding the coarse β-carotene dispersion to obtain a β-carotene nano-dispersion liquid;

[0011] The beta-carotene nano-dispersed liquid is dried to obtain the beta-carotene-polyphenol eutectic microcapsules.

[0012] Preferably, the mass ratio of the β-carotene crystals to the polyphenols is (3-30):1.

[0013] Preferably, the polyphenols include one or more of curcumin, tea polyphenols, epigallocatechin gallate, resveratrol, α-tocopherol, ascorbyl palmitate, tea polyphenol palmitate, chlorogenic acid, ferulic acid, anthocyanidin, quercetin and tartrazine.

[0014] Preferably, the particle size of the β-carotene crystals is 0.1 to 0.3 mm, and the ratio of the all-trans isomer is 97.5 to 98.5 wt%.

[0015] Preferably, the temperature of the supercritical CO2 reaction is 31-40°C, the CO2 flow rate is 10-20 mL / min, the pressure is 7.2-12 MPa, and the time is 5-40 min.

[0016] Preferably, the protective colloid solution comprises an emulsifier, an antioxidant and water, the mass ratio of the emulsifier to the β-carotene-polyphenol co-crystal is (2-3):1, and the mass of the antioxidant is 5-10% of the mass of the β-carotene-polyphenol co-crystal.

[0017] Preferably, the diameter of the grinding beads used in the grinding is 0.1 to 0.6 mm.

[0018] Preferably, the grinding time is 5 to 30 minutes, the rotation speed is 1500 to 3500 rpm, and the temperature is 15 to 25°C.

[0019] Preferably, the drying is spray drying, the inlet air temperature of the spray drying is 100-130°C, the outlet air temperature is 75-85°C, and the feed rate is 100-300 mL / h

[0020] The present invention also provides beta-carotene-polyphenol eutectic microcapsules prepared by the preparation method described in the above technical solution.

[0021] The invention provides a preparation method of beta-carotene-polyphenol eutectic microcapsules, comprising the following steps: mixing beta-carotene crystals and polyphenols and subjecting them to a supercritical CO2 reaction to obtain beta-carotene-polyphenol eutectic; dispersing the beta-carotene-polyphenol eutectic in a protective colloid solution, and then shearing the solution to obtain a coarse beta-carotene dispersion; grinding the coarse beta-carotene dispersion to obtain a nano-dispersion beta-carotene liquid; and drying the nano-dispersion beta-carotene liquid to obtain the beta-carotene-polyphenol eutectic microcapsules.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention first prepares β-carotene-polyphenol cocrystals using supercritical CO2 fluid technology to reduce the strong hydrophobicity of β-carotene, thereby increasing the β-carotene loading capacity. The β-carotene-polyphenol cocrystals are then sheared with a protective colloid, the resulting β-carotene crude dispersion is ground, and then dried to obtain the β-carotene-polyphenol cocrystal microcapsules. The polyphenols in the β-carotene-polyphenol cocrystals of the present invention can inhibit the oxidation and isomerization of β-carotene. The prepared β-carotene-polyphenol cocrystal microcapsules have a high all-trans isomer ratio (96.5-97.5 wt%) and a high loading capacity (β-carotene content of 20-22 wt%). The method of the present invention is simple and fast, and has the advantages of simplicity, safety, environmental protection, and economy.

[0024] Furthermore, the present invention prepares β-carotene-polyphenol cocrystals through a supercritical CO2 reactor, which can not only effectively reduce the hydrophobicity of β-carotene, but also shorten the grinding time and improve the grinding efficiency.

[0025] Furthermore, the present invention does not require high-temperature melting and organic reagent treatment, and can provide the β-carotene-polyphenol cocrystal microcapsules with a higher loading capacity, a higher all-trans isomer ratio, and better product stability.

[0026] The present invention also provides β-carotene-polyphenol eutectic microcapsules prepared by the preparation method described in the above technical solution. The β-carotene-polyphenol eutectic microcapsules of the present invention are nano-scale high-load, high-all-trans β-carotene-polyphenol eutectic microcapsules, and are β-carotene-polyphenol eutectic microcapsules with better performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 DSC curves of β-carotene, EGCG and their cocrystals;

[0028] Figure 2 The DSC curves of β-carotene, curcumin and their cocrystals are shown;

[0029] Figure 3 The DSC curves of β-carotene, tea polyphenol palmitate and their cocrystals are shown below;

[0030] Figure 4 The graph shows the change curve of the average particle size of β-carotene during the grinding process of Example 1 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0031] The present invention provides a method for preparing β-carotene-polyphenol cocrystal microcapsules, comprising the following steps:

[0032] β-carotene crystals and polyphenols are mixed and subjected to supercritical CO2 reaction to obtain β-carotene-polyphenol cocrystals;

[0033] dispersing the β-carotene-polyphenol co-crystal in a protective colloid solution, and then shearing the solution to obtain a β-carotene coarse dispersion;

[0034] grinding the coarse β-carotene dispersion to obtain a β-carotene nano-dispersion liquid;

[0035] The beta-carotene nano-dispersed liquid is dried to obtain the beta-carotene-polyphenol eutectic microcapsules.

[0036] In the present invention, unless otherwise specified, the raw materials used are commercially available products in the art.

[0037] The present invention mixes beta-carotene crystals and polyphenols and performs supercritical CO2 reaction to obtain beta-carotene-polyphenol eutectic.

[0038] In the present invention, the mass ratio of the β-carotene crystals to the polyphenols is preferably (3-30):1, specifically 3:1, 6:1, 8:1, 10:1, 15:1, 20:1, 25:1, 20:2.8, 20:3.1 or 30:1. The present invention uses β-carotene as the main component and polyphenols as ligands, maintaining the β-carotene in the majority. If the polyphenol ratio is too high, the polyphenols compete with the β-carotene for the hydrophobic binding sites under the condition of limited hydrophobic binding sites of the emulsifier, and the β-carotene cannot form a stable embedding structure, resulting in the inability to prepare high-load β-carotene-polyphenol cocrystal microcapsules.

[0039] In the present invention, the polyphenols preferably include one or more of curcumin, tea polyphenols, epigallocatechin gallate (EGCG), resveratrol, α-tocopherol, ascorbyl palmitate, tea polyphenol palmitate, chlorogenic acid, ferulic acid, anthocyanidin, quercetin and tartrazine.

[0040] In the present invention, the particle size of the β-carotene crystals is preferably 0.1-0.3 mm, specifically 0.1, 0.2 or 0.3 mm, and the ratio of the all-trans isomer is preferably 97.5-98.5 wt%, specifically 97.5 wt%, 98.2 wt% or 98.5 wt%.

[0041] In the present invention, the temperature of the supercritical CO2 reaction is preferably 31 to 40°C, specifically 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40°C, the CO2 flow rate is preferably 10 to 20 mL / min, specifically 10, 15 or 20 mL / min, the pressure is preferably 7.2 to 12 MPa, specifically 7.2, 8, 9, 10, 11 or 12 MPa, the time is preferably 5 to 40 min, specifically 5, 10, 20, 25, 30 or 40 min, the supercritical CO2 reaction is preferably The reaction is carried out under stirring, and the stirring speed is preferably 200 to 1500 rpm, specifically 200, 500, 1000, 1200 or 1500 rpm. During the supercritical CO2 reaction, the β-carotene and polyphenol molecules combine through supramolecular interactions to form a composite crystal material, i.e., the β-carotene-polyphenol eutectic. Limiting the temperature, CO2 flow rate, pressure and rotation speed of the supercritical CO2 reaction within the above ranges can avoid the problem of limited interaction between β-carotene and polyphenols, which leads to failure of eutectic formation.

[0042] In the present invention, the supercritical CO2 reaction is preferably carried out in a supercritical CO2 reactor.

[0043] After obtaining the β-carotene-polyphenol co-crystal, the present invention disperses the β-carotene-polyphenol co-crystal in a protective colloid solution, and then shears the solution to obtain a β-carotene coarse dispersion.

[0044] In the present invention, the protective colloid solution comprises an emulsifier, an antioxidant and water. The mass ratio of the emulsifier to the β-carotene-polyphenol co-crystal is preferably (2-3):1, specifically 2:1, 2.75:1 or 3:1. If the amount of the emulsifier is too high, the loading amount of the β-carotene will be reduced, and microcapsules with a high loading amount cannot be prepared. If the amount of the emulsifier is too low, the β-carotene-polyphenol co-crystal cannot be effectively embedded, resulting in instability of the microcapsule structure. The mass of the antioxidant is preferably 5-10% of the mass of the β-carotene-polyphenol co-crystal, specifically 5%, 6.5%, 7%, 8%, 9% or 10%. If the amount of the antioxidant is too high, the loading amount of the β-carotene will be reduced, and microcapsules with a high loading amount cannot be prepared. If the amount of the antioxidant is too low, its antioxidant function cannot be exerted, resulting in oxidative degradation of the β-carotene.

[0045] In the present invention, the mass concentration of the protective colloid solution is preferably 10-20 wt%, specifically 10%, 15% or 20%. If the mass concentration of the protective colloid solution is too low, it is not conducive to subsequent drying, and if it is too high, it is not conducive to grinding.

[0046] In the present invention, the emulsifier preferably includes one or more of gum arabic, soybean polysaccharide, whey protein isolate, soybean protein isolate, sodium starch octenylsuccinate and maltodextrin. When the emulsifier is preferably a mixture, the present invention has no special limitation on the mass ratio of the substances in the mixture, and a mixture of any proportion can be used. In a specific embodiment of the present invention, the emulsifier is a mixture of sodium starch octenylsuccinate and maltodextrin in a mass ratio of 8:1.

[0047] In the present invention, the antioxidant preferably includes one or more of BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene), ethoxyquin, TBHQ (tert-butylhydroquinone), ascorbic acid, sodium L-ascorbate, and sodium D-isoascorbate. When the antioxidant is preferably a mixture, the present invention has no special limitation on the mass ratio of the substances in the mixture, and a mixture of any proportion can be used. In a specific embodiment of the present invention, the antioxidant is a mixture of BHA and sodium L-ascorbate in a mass ratio of 2:1.

[0048] In the present invention, the shearing speed is preferably 8000-15000 rpm, specifically 8000, 10000, 12000, 14000 or 15000 rpm; the shearing time is preferably 5-30 min, specifically 5, 10, 15, 20, 25 or 30 min.

[0049] In the present invention, after shearing, the filter is preferably passed through an 80-mesh filter cloth. If there is filter residue, the filter residue is added with water and re-sheared for 3 minutes, and then passed through an 80-mesh filter cloth. The re-shearing speed is preferably 8000-15000 rpm, specifically 8000, 10000, 12000, 14000 or 15000 rpm.

[0050] After obtaining the beta-carotene coarse dispersion, the present invention grinds the beta-carotene coarse dispersion to obtain the beta-carotene nano-dispersion liquid.

[0051] In the present invention, the diameter of the grinding beads used in the grinding is preferably 0.1 to 0.6 mm, specifically 0.1, 0.2, 0.3, 0.4, 0.5 or 0.6 mm, and the material of the grinding beads is preferably ZrO2.

[0052] In the present invention, the mass ratio of β-carotene-polyphenol co-crystal to grinding beads in the β-carotene crude dispersion is preferably 1:(50-100), specifically 1:50, 1:80 or 1:100.

[0053] In the present invention, the grinding time is preferably 5 to 30 minutes, specifically 5, 10, 15, 20, 25 or 30 minutes, the rotation speed is preferably 1500 to 2500 rpm, specifically 1500, 2000, 2100, 2200 or 2500 rpm, and the temperature is preferably 15 to 25° C., specifically 15, 20, 21, 22 or 24° C. The longer the grinding time, the faster the rotation speed and the higher the temperature, the more likely the β-carotene is to undergo oxidative degradation and cis-isomerization. By limiting the grinding time, rotation speed and temperature to the above ranges, the present invention can avoid oxidative degradation of β-carotene (manifested as a lower loading during the grinding process) and cis-isomerization.

[0054] In the present invention, the pore diameter of the grinding filter is preferably 0.2 to 0.4 mm, specifically 0.2, 0.3 or 0.4 mm.

[0055] In the present invention, the grinding is preferably performed in a nano-grinder.

[0056] After obtaining the beta-carotene nano-dispersed liquid, the present invention dries the beta-carotene nano-dispersed liquid to obtain the beta-carotene-polyphenol eutectic microcapsules.

[0057] In the present invention, the drying is preferably spray drying, and the inlet temperature of the spray drying is preferably 100-130°C, specifically 100, 105, 110, 115, 120, 125 or 130°C, the outlet temperature is preferably 75-85°C, specifically 75, 76, 77, 78, 79, 80, 81, 82, 83, 84 or 85°C, and the feed rate is preferably 100-300 mL / h, specifically 100, 150, 180, 200, 250 or 300 mL / h.

[0058] The present invention does not require the addition of toxic organic solvents or solubilizing oils during the entire preparation process, does not require high-temperature melting treatment, and has relatively mild preparation conditions. Therefore, the method has the advantages of simplicity, safety, environmental protection, and economy. The beta-carotene-polyphenol cocrystal is prepared by a supercritical CO2 reactor, which effectively reduces the hydrophobicity of the beta-carotene and improves the grinding efficiency. The beta-carotene-polyphenol cocrystal microcapsules with a high loading (20-22 wt%) can be obtained by grinding in a short time. The polyphenols in the beta-carotene-polyphenol cocrystal can inhibit the isomerization of the beta-carotene. The prepared beta-carotene-polyphenol cocrystal microcapsules have a high all-trans isomer ratio (96.5-97.5 wt%).

[0059] The present invention also provides beta-carotene-polyphenol eutectic microcapsules prepared by the preparation method described in the above technical solution.

[0060] In the present invention, the loading amount of β-carotene in the β-carotene-polyphenol cocrystal microcapsules is preferably 20-22 wt%, specifically 20.19 wt%, 20.71 wt%, 21 wt%, 21.63 wt%, or 22 wt%.

[0061] In the present invention, the rehydrated particle size of the β-carotene-polyphenol cocrystal microcapsules is preferably 200-500 nm, specifically 387.4, 297.4 or 243.8 nm.

[0062] In the present invention, the β-carotene-polyphenol cocrystal microcapsules are preferably spherical powders.

[0063] In the present invention, the proportion of all-trans isomers in the β-carotene in the β-carotene-polyphenol cocrystal microcapsules is preferably 96.5-97.5 wt%, specifically 96.5 wt%, 96.7 wt%, 97.3 wt% or 97.5 wt%.

[0064] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0065] In an embodiment of the present invention, the loading amount and embedding efficiency of β-carotene-polyphenol cocrystal microcapsules were determined as follows: First, 0.1 g of β-carotene-polyphenol cocrystal microcapsules were placed in 100 mL of deionized water to obtain a 0.1 wt% rehydrated dispersion. Then, the β-carotene in the rehydrated dispersion was extracted multiple times using a mixed reagent of anhydrous ethanol and n-hexane (1:3, v / v) until the dispersion was colorless. The absorbance of the β-carotene extract was measured at a wavelength of 450 nm using an ultraviolet-visible spectrophotometer (UV-1800, Shimadzu Corporation, Japan). The β-carotene standard curve (y = 0.2623x + 0.0247, R 2 =0.9996) to quantitatively calculate the β-carotene content in the extract. The formula for calculating the loading capacity and embedding efficiency of the β-carotene-polyphenol cocrystal microcapsules is as follows:

[0066] β-carotene loading (%) = mass of embedded β-carotene (mg) / total mass of β-carotene-polyphenol cocrystal microcapsules (mg) × 100%

[0067] β-carotene embedding efficiency (%) = embedded β-carotene mass (mg) / total β-carotene mass (mg) × 100%

[0068] In the present embodiment, the ratio of the all-trans isomer of β-carotene was determined as follows: the ratio of the cis- and trans-isomers of β-carotene was quantitatively determined using a high-performance liquid chromatograph (Agilent-1100, Agilent, USA) equipped with a DAD detector. 10 mg of β-carotene was accurately weighed and dissolved in 20 mL of chromatographic-grade dichloromethane. 0.5 mL of the solution was accurately aspirated and diluted to 9 mL with chromatographic-grade dichloromethane. The diluted solution was then filtered through an organic filter with a pore size of 0.45 μm to remove impurities before injection. The HPLC parameters were as follows: a C30 column (250 × 4.6 mm, YMC, Japan), a column temperature of 25°C, a wavelength of 450 nm, mobile phase A consisting of a mixture of methanol, acetonitrile, and purified water (73.5:24.5:2, v / v), mobile phase B consisting of dimethyl tert-butyl ether, and a mobile phase flow rate of 1 mL / min. The ratio of all-trans isomers of β-carotene was determined by peak area integration method.

[0069] In the embodiments of the present invention, the oil-water partition coefficient (lgP) is used to indicate the hydrophobicity of the β-carotene-polyphenol cocrystal. The larger the lgP value, the stronger the hydrophobicity of the cocrystal. The logP value of the β-carotene-polyphenol cocrystal is determined as follows: n-octanol and water are added to a stoppered conical flask in a volume ratio of 1:1, placed on a magnetic stirrer and stirred continuously for 24 hours, allowed to stand overnight, and the two phases are separated to obtain water-saturated n-octanol and n-octanol-saturated water, which are stored for future use. Accurately weigh 10.0 mg of the cocrystal and add it to 3 mL of water-saturated n-octanol. Balance for 4 hours until completely dispersed, then centrifuge. Take 1 mL of the supernatant as C0, take another 1 mL and mix it with an equal volume of n-octanol-saturated water. After balancing for 24 hours, let it stand and separate. Take the n-octanol layer as C, appropriately dilute and filter through a 0.22 mm microporous membrane, and then perform high-performance liquid chromatography determination. The lgP calculation formula is as follows:

[0070] lgP=lg[C0 / (C0-C)]

[0071] In the present embodiment, the thermal behavior of β-carotene, polyphenols and their cocrystals was determined using a differential scanning calorimeter (DSC). 5 mg of the sample was placed in a standard aluminum crucible and sealed with a perforated aluminum sheet. The sample was heated from 30°C to 250°C at a constant heating rate of 10°C / min, during which high-purity nitrogen was introduced at a constant rate of 20 mL / min. The melting point temperature T of the sample was determined using the provided analytical software. m Perform the measurement.

[0072] In the present embodiment, the solubility of β-carotene was determined as follows: 0.1 g of β-carotene was accurately weighed and added to 100 mL of deionized water (pH = 7) and stirred thoroughly. 10 mL of the sample was centrifuged at 15,000 rpm for 60 min at 10°C. The supernatant was filtered through a 0.45 μm nylon filter to further remove undissolved particles. The mass of dissolved β-carotene was calculated using the UV-Vis spectrophotometric method described above. The β-carotene solubility calculation formula is as follows:

[0073] β-carotene solubility (%) = dissolved β-carotene mass (mg) / total β-carotene mass (mg) × 100%

[0074] In this example, the particle size of the rehydrated dispersion of the β-carotene-polyphenol cocrystal microcapsules was measured as follows: The particle size of the β-carotene nanodispersion and the rehydrated dispersion was measured using a Zeta-sizer (ZS90, Malvern, UK) based on the principle of dynamic light scattering. Prior to measurement, the β-carotene nanodispersion and the rehydrated dispersion (0.1 g / 100 g, w / v) were diluted 100-fold with deionized water to avoid multiple light scattering effects.

[0075] Example 1

[0076] 20g of β-carotene crystals (provided by Zhejiang Xinhecheng Co., Ltd., with a purity of 98.5wt% and a ratio of 98.2wt% all-trans isomers) and 2g of epigallocatechin gallate were placed in a supercritical CO2 reactor. CO2 was introduced into the reactor at a flow rate of 10mL / min, pressurized to 10MPa at 35°C, and stirred at 1000rpm for 20min. After the treatment, the CO2 was released to obtain β-carotene-EGCG cocrystals. 55g of emulsifier (a mixture of sodium starch octenylsuccinate and maltodextrin in a mass ratio of 8:1) and 1.3g of antioxidant (a mixture of BHA and sodium L-ascorbate in a mass ratio of 2:1) were dissolved in deionized water and mixed thoroughly to obtain a protective colloid solution. The β-carotene-EECG cocrystal was dispersed in a uniformly mixed protective colloid solution, sheared at 10,000 rpm for 15 minutes, and then filtered through an 80-mesh filter cloth. If there was any filter residue, the filter residue was sheared with a small amount of water for 3 minutes, filtered through an 80-mesh filter cloth, and mixed with the above filtrate to obtain a β-carotene crude dispersion. The β-carotene coarse dispersion was added to a nano-grinder (ZrO2 grinding beads with a diameter of 0.2 mm, a grinding filter with a pore size of 0.2 mm, and grinding at 2000 rpm for 20 min, with the grinding temperature at 21° C. under the control of a circulating chiller) to obtain a β-carotene nano-dispersion liquid. The nano-dispersion liquid was spray-dried at an inlet air temperature of 105° C., an outlet air temperature of 75° C., and a feed rate of 150 mL / h. The obtained β-carotene-polyphenol eutectic microcapsules had a rehydrated particle size of 387.4 nm, a β-carotene loading of 21.63 wt %, and an all-trans isomer ratio of 97.3 wt %.

[0077] Comparative Example 1

[0078] The same as Example 1, except that epigallocatechin gallate was not added and the supercritical CO2 reaction was not performed, the prepared β-carotene-polyphenol cocrystal microcapsules had a particle size of 693.7 nm after rehydration, a β-carotene loading of 18.61 wt%, and a ratio of the all-trans isomer of 95.8 wt%.

[0079] Comparative Example 2

[0080] The same as Example 1, except that epigallocatechin gallate was not added, the particle size of the prepared β-carotene-polyphenol cocrystal microcapsules after rehydration was 685.8 nm, the β-carotene loading was 18.57 wt%, and the ratio of the all-trans isomer was 95.5 wt%.

[0081] Example 2

[0082] 20g of β-carotene crystals (provided by Zhejiang Xinhecheng Co., Ltd., with a purity of 98.5wt% and a ratio of 98.2wt% of the all-trans isomer) and 2.8g of curcumin were placed in a supercritical CO2 reactor. CO2 was introduced into the reactor at a flow rate of 15mL / min, pressurized to 12MPa at 37°C, and stirred at 1200rpm for 25min. After the treatment, the CO2 was released to obtain β-carotene-curcumin cocrystals. 55g of emulsifier (a mixture of sodium starch glycolate octenylsuccinate and maltodextrin in a mass ratio of 8:1) and 1.3g of antioxidant (a mixture of BHA and sodium L-ascorbate in a mass ratio of 2:1) were dissolved in deionized water and mixed thoroughly to obtain a protective colloid solution. The β-carotene-curcumin cocrystals were dispersed in a uniformly mixed protective colloid solution, sheared at 10,000 rpm for 15 minutes, and then filtered through an 80-mesh filter cloth. If there was any filter residue, the filter residue was sheared with a small amount of water for 3 minutes, filtered through an 80-mesh filter cloth, and mixed with the above filtrate to obtain a β-carotene crude dispersion. The β-carotene coarse dispersion was added to a nano-grinder (ZrO2 grinding beads with a diameter of 0.2 mm, a grinding filter with a pore size of 0.2 mm, and grinding at 2200 rpm for 15 min, with the grinding temperature at 22° C. under the control of a circulating chiller) to obtain a β-carotene nano-dispersion liquid. The nano-dispersion liquid was spray-dried at an inlet air temperature of 120° C., an outlet air temperature of 82° C., and a feed rate of 180 mL / h. The obtained β-carotene-polyphenol eutectic microcapsules had a rehydrated particle size of 297.4 nm, a β-carotene loading of 20.19 wt %, and an all-trans isomer ratio of 96.7 wt %.

[0083] Comparative Example 3

[0084] The same as Example 2, except that curcumin was not added, the particle size of the prepared β-carotene-polyphenol cocrystal microcapsules after rehydration was 662.7 nm, the β-carotene loading was 17.07 wt%, and the ratio of the all-trans isomer was 94.1 wt%.

[0085] Example 3

[0086] 20g of β-carotene crystals (provided by Zhejiang Xinhecheng Co., Ltd., with a purity of 98.5wt% and a 98.2wt% all-trans isomer ratio) and 3.1g of tea polyphenol palmitate were placed in a supercritical CO2 reactor. CO2 was introduced into the reactor at a flow rate of 18mL / min, pressurized to 11MPa at 34°C, and stirred at 1500rpm for 30 minutes. After the reaction was completed, the CO2 was released to obtain β-carotene-tea polyphenol palmitate cocrystals. 55g of emulsifier (a mixture of sodium starch octenylsuccinate and maltodextrin in a mass ratio of 8:1) and 1.3g of antioxidant (a mixture of BHA and sodium L-ascorbate in a mass ratio of 2:1) were dissolved in deionized water and mixed thoroughly to obtain a protective colloid solution. The β-carotene-tea polyphenol palmitate eutectic was dispersed in a uniformly mixed protective colloid solution, sheared at 10,000 rpm for 15 minutes, and then filtered through an 80-mesh filter cloth. If there was any filter residue, the filter residue was sheared with a small amount of water for 3 minutes, filtered through an 80-mesh filter cloth, and mixed with the above filtrate to obtain a β-carotene crude dispersion. The β-carotene coarse dispersion was added to a nano-grinder (ZrO2 grinding beads with a diameter of 0.2 mm, a grinding filter with a pore size of 0.2 mm, and grinding at 2100 rpm for 30 min, with the grinding temperature at 21° C. under the control of a circulating chiller) to obtain a β-carotene nano-dispersion liquid. The nano-dispersion liquid was spray-dried at an inlet air temperature of 110° C., an outlet air temperature of 78° C., and a feed rate of 150 mL / h. The obtained β-carotene-polyphenol eutectic microcapsules had a rehydrated particle size of 243.8 nm, a β-carotene loading of 20.71 wt %, and an all-trans isomer ratio of 96.5 wt %.

[0087] Comparative Example 4

[0088] The same as Example 4, except that tea polyphenol palmitate was not added, the particle size of the prepared β-carotene-polyphenol cocrystal microcapsules after rehydration was 688.1 nm, the β-carotene loading was 18.63 wt%, and the ratio of the all-trans isomer was 94.6 wt%.

[0089] Example 4

[0090] Optimization experiment of the mass ratio of β-carotene crystals and polyphenols

[0091] a) β-carotene-polyphenol cocrystal microcapsules were prepared using a single wet grinding process, and the mass ratio of β-carotene crystals to polyphenols was optimized. First, 14 g of OSA-modified starch was dispersed in 400 mL of deionized water and incubated at 80°C in a water bath until completely dissolved. Then, β-carotene crystals and polyphenols (total mass 5 g) in varying mass ratios, along with 1 g of antioxidant, were slowly added to the OSA-modified starch solution. Simultaneously, a high-speed shear was used at 8000 rpm to shear the mixture until completely dispersed, yielding a coarse β-carotene dispersion.

[0092] b) The crude β-carotene dispersion obtained in step a) was injected into a grinder (FSW-1.0, Shanghai Yile Mechanical and Electrical Equipment Co., Ltd.) containing 2.5 kg of zirconium oxide beads (diameter 0.4-0.6 mm) at a grinding speed of 1800 rpm, a grinding temperature of 20° C., and a grinding time of 90 min.

[0093] c) After grinding, the obtained β-carotene nanodispersion was spray-dried at a feed rate of 300 mL / h, a spray drying air inlet temperature of 105° C., and an outlet temperature of 70° C. to obtain β-carotene-polyphenol cocrystal microcapsules.

[0094] d) Detecting the embedding efficiency and loading rate of β-carotene-polyphenol cocrystal microcapsules to optimize the mass ratio of β-carotene crystals to polyphenols.

[0095] Table 1 shows the results of the β-carotene loading and entrapment efficiency measurements in microcapsules using a β-carotene / polyphenol blend system. This indicates that the present invention utilizes β-carotene as the main component and polyphenols as ligands, maintaining a predominant β-carotene content. However, if the polyphenol ratio is too high, the polyphenols compete with β-carotene for the limited hydrophobic binding sites of the emulsifier, preventing the β-carotene from forming a stable entrapment structure and ultimately preventing the preparation of high-load β-carotene-polyphenol cocrystal microcapsules.

[0096] Table 1 Results of the determination of β-carotene loading and embedding efficiency in microcapsules under β-carotene / polyphenol blend system

[0097]

[0098] Example 5

[0099] Optimization experiment of mass ratio of emulsifier and β-carotene-polyphenol eutectic

[0100] a) β-carotene-polyphenol cocrystal microcapsules were prepared using a supercritical fluid-wet grinding coupled process, optimizing the mass ratio of emulsifier to cocrystal. First, 20 g of β-carotene crystals and 2 g of curcumin were placed in a supercritical CO2 reactor. CO2 was introduced into the reactor at a flow rate of 15 mL / min. The reactor was pressurized to 12 MPa at 37°C and stirred at 1200 rpm for 25 minutes. After the reaction was complete, the CO2 was released to obtain β-carotene-curcumin cocrystals.

[0101] b) Disperse OSA modified starch in 400 mL of deionized water and incubate in an 80°C water bath until completely dissolved. Then, slowly add β-carotene-curcumin cocrystals and 1 g of antioxidant to the OSA modified starch solution, wherein the mass ratio of OSA modified starch to cocrystal is 1:2, 1:1, 2:1, 2:1, and 8:1 (total mass of the two is 19 g). Shear the mixture at 8000 rpm using a high-speed shearing machine until the material is completely dispersed, thereby obtaining a crude β-carotene dispersion.

[0102] c) The crude β-carotene dispersion obtained in step b) was injected into a grinder (FSW-1.0, Shanghai Yile Mechanical and Electrical Equipment Co., Ltd.) containing 2.5 kg of zirconium oxide beads (diameter 0.4-0.6 mm) at a grinding speed of 1800 rpm, a grinding temperature of 20° C., and a grinding time of 10 min.

[0103] d) After grinding, the obtained β-carotene nanodispersion was spray-dried at a feed rate of 300 mL / h, an air inlet temperature of 105° C., and an air outlet temperature of 70° C. to obtain β-carotene-polyphenol cocrystal microcapsules.

[0104] e) Detecting the embedding efficiency and loading rate of β-carotene-polyphenol cocrystal microcapsules to optimize the mass ratio of emulsifier to cocrystal.

[0105] Table 2 shows the results of the determination of β-carotene loading and embedding efficiency in microcapsules under different mass ratios of emulsifier to β-carotene-polyphenol eutectic. It can be seen that when the amount of emulsifier is too high or too low, the loading amount of β-carotene will be reduced, and microcapsules with high loading amount cannot be prepared. When the amount of emulsifier is too low, the β-carotene-polyphenol eutectic cannot be effectively embedded, resulting in instability of the microcapsule structure.

[0106] Table 2 Results of β-carotene loading and embedding efficiency in microcapsules under different emulsifier to β-carotene-polyphenol eutectic mass ratios

[0107]

[0108] Example 6

[0109] Wet grinding process parameter optimization experiment

[0110] a) A β-carotene nanodispersion was prepared using a supercritical fluid-wet grinding coupled process, and the wet grinding process parameters were optimized. First, 20 g of β-carotene crystals and 2 g of curcumin were placed in a supercritical CO2 reactor. CO2 was introduced into the reactor at a rate of 15 mL / min. The reactor was pressurized to 12 MPa at 37°C and stirred at 1200 rpm for 25 minutes. After the treatment, the CO2 was released to obtain β-carotene-curcumin cocrystals.

[0111] b) Disperse the OSA modified starch in 400 mL of deionized water and incubate in an 80°C water bath until completely dissolved. Then, slowly add 5 g of β-carotene-curcumin cocrystals and 1 g of an antioxidant to 14 g of the OSA modified starch solution. Shear the mixture at 8000 rpm using a high-speed shearing machine until the mixture is completely dispersed, thereby obtaining a crude β-carotene dispersion.

[0112] c) injecting the crude β-carotene dispersion obtained in step b) into a grinder (FSW-1.0, Shanghai Yile Mechanical and Electrical Equipment Co., Ltd.) containing 2.5 kg of zirconium oxide beads (diameter 0.4-0.6 mm), grinding at speeds of 1500, 2000, 2500, and 3000 rpm, respectively, and at temperatures of 15, 20, 24, and 29° C., respectively, for a total grinding time of 60 min to obtain a β-carotene nanodispersion.

[0113] d) The loading rate and cis-isomer ratio of the β-carotene nanodispersion were monitored every 15 minutes. The wet grinding process parameters were used. The results are shown in Table 3. It can be seen that the longer the grinding time and the faster the rotation speed, the more likely the β-carotene is to undergo oxidative degradation and cis-isomerization. The present invention controls the grinding time and rotation speed to avoid oxidative degradation of β-carotene (manifested as a lower loading during the grinding process) and cis-isomerization.

[0114] Table 3 β-carotene loading and cis-isomer determination results under different wet grinding process parameters

[0115]

[0116]

[0117] Example 7

[0118] β-Carotene-polyphenol cocrystal formation verification experiment

[0119] In order to verify whether β-carotene-polyphenol eutectic is successfully formed under the action of supercritical CO2 fluid, the DSC curves of β-carotene, polyphenols and their eutectic were measured. The results are shown in Figures 1 to 3 . Figure 1 is the DSC curve of β-carotene, EGCG and their cocrystal, Figure 2 is the DSC curve of β-carotene, curcumin and their cocrystal, Figure 3 The DSC curves for β-carotene, tea polyphenol palmitate, and their cocrystals are shown in the figure. The DSC curves for the eutectic show new melting peaks distinct from those for β-carotene and the individual polyphenols, indicating the formation of a new eutectic phase. The shift in the eutectic's melting point is primarily due to the presence of weak hydrogen bonds within the eutectic structure.

[0120] Table 4 shows the solubility and lgP values ​​of β-carotene and its cocrystals. It can be seen that compared with β-carotene crystals, the hydrophobicity of β-carotene-polyphenol cocrystals is reduced, as evidenced by increased solubility and decreased lgP values. This is because the cocrystal technique rearranges the β-carotene crystal molecules, and the introduction of polyphenols reduces its lattice energy, thereby increasing the affinity of the β-carotene crystals for the solvent.

[0121] Table 4 Solubility and IgP size determination results of β-carotene and its cocrystal

[0122] type Solubility / % lgP beta-carotene 0.00 13.43 β-Carotene-EGCG cocrystal 3.14 9.81 β-Carotene-Curcumin Cocrystal 1.15 10.72 β-Carotene-Tea Polyphenol Palmitate Cocrystal 0.32 12.95

[0123] Figure 4 The curves showing the change in average particle size of β-carotene during the grinding process of Example 1 and Comparative Examples 1-2 show that the supercritical CO2 reaction can reduce the high hydrophobicity of β-carotene and shorten the grinding time. Under the same conditions, the grinding efficiency of the eutectic system is higher. At the same time, the introduction of strong antioxidant polyphenols can effectively prevent the oxidative degradation and cis-isomerization of β-carotene during the grinding process, maintaining a high all-trans isomer ratio and a high loading amount of β-carotene.

[0124] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing β-carotene-polyphenol cocrystal microcapsules, characterized in that: The following steps are involved: β-carotene crystals and polyphenols are mixed and subjected to supercritical CO2 reaction to obtain β-carotene-polyphenol cocrystals; dispersing the β-carotene-polyphenol co-crystal in a protective colloid solution, and then shearing the solution to obtain a β-carotene coarse dispersion; grinding the coarse β-carotene dispersion to obtain a β-carotene nano-dispersion liquid; The beta-carotene nano-dispersed liquid is dried to obtain the beta-carotene-polyphenol eutectic microcapsules.

2. The preparation method according to claim 1, characterized in that The mass ratio of the beta-carotene crystals to the polyphenols is (3-30):

1.

3. The preparation method according to claim 1 or 2, characterized in that The polyphenols include one or more of curcumin, tea polyphenols, epigallocatechin gallate, resveratrol, α-tocopherol, ascorbyl palmitate, tea polyphenol palmitate, chlorogenic acid, ferulic acid, anthocyanidin, quercetin and tartrazine.

4. The preparation method according to claim 1 or 2, characterized in that The particle size of the beta-carotene crystals is 0.1-0.3 mm, and the ratio of the all-trans isomer is 97.5-98.5 wt %.

5. The preparation method according to claim 1, characterized in that The temperature of the supercritical CO2 reaction is 31-40°C, the CO2 flow rate is 10-20 mL / min, the pressure is 7.2-12 MPa, and the time is 5-40 min.

6. The preparation method according to claim 1, characterized in that The protective colloid solution comprises an emulsifier, an antioxidant and water. The mass ratio of the emulsifier to the beta-carotene-polyphenol cocrystal is (2-3):1, and the mass of the antioxidant is 5-10% of the mass of the beta-carotene-polyphenol cocrystal.

7. The preparation method according to claim 1, characterized in that The diameter of the grinding beads used in the grinding is 0.1 to 0.6 mm.

8. The preparation method according to claim 1 or 7, characterized in that The grinding time is 5 to 30 minutes, the rotation speed is 1500 to 3500 rpm, and the temperature is 15 to 25°C.

9. The preparation method according to claim 1, characterized in that The drying is spray drying, the air inlet temperature of the spray drying is 100-130° C., the air outlet temperature is 75-85° C., and the feed rate is 100-300 mL / h.

10. β-carotene-polyphenol cocrystal microcapsules prepared by the preparation method according to any one of claims 1 to 9.

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