Preparation device and method of beta-carotene emulsion and application of beta-carotene emulsion

Abstract

The invention discloses a preparation device and method of beta-carotene emulsion and application. The preparation device comprises a heating kettle, a dissolving kettle and an emulsifying kettle which are communicated in sequence, an eccentrically mounted stirring paddle is arranged at the bottom of the dissolving kettle; the dissolving kettle is also provided with an external circulation pipeline which is communicated with the liquid phase space and the gas phase space of the dissolving kettle; and a circulation pump is arranged on the external circulation pipeline. The preparation device is simple in production equipment, simple in preparation process and high in dissolution speed, and the cis-isomer content in the prepared beta-carotene emulsion is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and relates to a device and method for preparing a beta-carotene emulsion with simple production equipment, a concise preparation process, a fast dissolution rate, and a low cis-isomer content in the emulsion. More specifically, the invention relates to the preparation and application of a flavor-enhanced beta-carotene emulsion. Background Art

[0002] β-carotene emulsions are typically prepared using three methods: grinding, solvent, and hot melt. While the grinding method produces an emulsion with a low cis-isomer content, it also suffers from low production efficiency. The solvent method produces an emulsion with a higher cis-isomer content and higher production efficiency than the grinding method. The hot melt method achieves the highest cis-isomer content and the highest production efficiency. The color of the emulsions produced by these various methods varies significantly, so the appropriate method is generally selected based on the desired color.

[0003] CN111838648A discloses an apparatus and method for producing a nanoscale food carotenoid emulsion. The method involves mixing a mixture of β-carotenoid, sodium ascorbate, and modified starch in a mass ratio of 10:1:39 with water in a mass ratio of 1:9, grinding the mixture to produce a crude emulsion containing 2% β-carotenoid and a particle size of 2-8 microns. The crude emulsion is then placed in a heat exchange chamber and rapidly heated to 160°C. The mixture then undergoes two-stage homogenization and flash evaporation to produce a nanoscale β-carotenoid emulsion containing 1.94% trans-β-carotenoid. However, this method places extremely high demands on the operating process, with residence times measured in seconds. In actual industrial production, this method is prone to unstable emulsion quality.

[0004] CN102524944B discloses a color regulator specifically designed to improve the appearance of reconstituted tobacco leaves and its preparation method: 10%-45% natural β-carotene and 20%-35% natural tomato red are subjected to supercritical extraction to obtain a crude solution, which is then purified using membrane separation reverse osmosis technology. β-cyclodextrin is used as an emulsifying wall material to obtain an emulsion. The emulsion is then mixed with 0.1%-0.5% citric acid, 0.01%-0.2% tannic acid, 0.15%-0.5% soda ash, 0.2%-0.45% guar gum, 0.05%-1.0% potassium acetate, and caramel to obtain an emulsion that can be used to color reconstituted tobacco leaves. This solution requires a high source of β-carotene raw material, is complex to process, and has high investment costs in actual industrial production.

[0005] CN113925157B discloses a β-carotene emulsion and its preparation method, which includes: adding an emulsifier to water to obtain an aqueous phase mixture; dissolving β-carotene in edible oil to obtain an oil phase mixture; mixing the aqueous phase mixture and the oil phase mixture in a certain proportion, and subjecting the mixture to high-speed shearing and ultrasonic emulsification to obtain the β-carotene emulsion. This solution has a low β-carotene content, with the concentration of β-carotene in the oil phase being only 0.01 to 2 mg / mL. The emulsifier used is a wheat bran and arabinoxylan-pea protein isolate complex. The emulsifier requires hydration, pH adjustment, high-temperature reaction, and vacuum freeze-drying, making large-scale production unfeasible.

[0006] The aforementioned patent does not detail the color, heat resistance, and other application indicators of interest to downstream applications of the prepared β-carotene emulsion. Currently, commercially available β-carotene emulsions generally have a narrow color control range and poor heat resistance, and their color and flavor cannot simultaneously meet the needs of various downstream applications. Summary of the Invention

[0007] In response to the above technical problems, the present invention aims to provide a preparation device for a β-carotene emulsion, a preparation method thereof, and an application thereof. The preparation device has simple production equipment, a concise preparation process, a fast dissolution rate, and the prepared β-carotene emulsion has a low cis-isomer content.

[0008] In order to solve the above problems, the present invention provides the following technical solutions:

[0009] A beta-carotene emulsion preparation device comprises a heating kettle, a dissolving kettle and an emulsifying kettle which are connected in sequence;

[0010] The heating kettle is used to heat the oil phase solvent for preparing the β-carotene emulsion;

[0011] The dissolving kettle is used to dissolve β-carotene in the oil phase solvent, and an eccentrically mounted stirring paddle is provided at the bottom of the kettle;

[0012] The dissolving kettle is also provided with an external circulation pipeline connecting the liquid phase space and the gas phase space of the dissolving kettle;

[0013] The outer circulation pipeline is provided with a circulation pump capable of circulating the material in the dissolving kettle multiple times.

[0014] When the preparation device of the present invention is used, an oil phase solvent containing no beta-carotene is heated in a heating kettle, and then the beta-carotene is dissolved in a dissolving kettle. The heat melting order of the beta-carotene is adjusted to reduce the heating time of the beta-carotene, and the dissolving device is improved to accelerate the dissolution speed of the beta-carotene, thereby ultimately reducing the content of the cis-isomer of beta-carotene, making the color of the beta-carotene more controllable, and reducing the crystal content in the beta-carotene emulsion to a certain extent, thereby improving the stability.

[0015] Preferably, the circulation pump is an emulsification pump or a closed centrifugal pump.

[0016] Preferably, the inlet of the external circulation pipeline is arranged on the other side of the lower part of the dissolution kettle opposite to the stirring paddle, and the outlet of the external circulation pipeline is arranged on the upper part of the dissolution kettle, which can further improve the dissolution rate of β-carotene.

[0017] Preferably, the inlet of the external circulation pipeline extends to the interior of the dissolving kettle cavity through an inlet pipe arranged inside the dissolving kettle, and a trumpet-shaped inlet is provided at the top of the inlet pipe.

[0018] Preferably, a nitrogen inlet pipe is provided at the highest point of the external circulation pipeline.

[0019] The present invention also provides a method for preparing a flavored β-carotene emulsion, which comprises the following steps in the above-mentioned device:

[0020] (1) heating a cosolvent, an antioxidant, and a compound low HLB value emulsifier in a heating kettle to obtain a mixed solvent (i.e., the oil phase solvent described above);

[0021] (2) adding a compound high HLB value emulsifier, a co-emulsifier, and water into an emulsifying kettle and dissolving them completely to obtain an aqueous phase;

[0022] (3) adding β-carotene crystals or β-carotene oil suspension into the dissolving kettle;

[0023] (4) placing the mixed solvent in the heating kettle into a dissolving kettle to dissolve the β-carotene crystals or the carotene oil suspension to obtain a first oil phase;

[0024] (5) adding a flavoring agent to the dissolving kettle to obtain a second oil phase;

[0025] (6) The second oil phase is added to an emulsifying kettle to contact with the water phase, and is fully emulsified after high-speed shearing to obtain a flavored β-carotene emulsion.

[0026] Preferably, the β-carotene crystals have a β-carotene content of ≥96%. The β-carotene oil suspension comprises β-carotene, vitamin E, and sunflower oil. The β-carotene content is 30-35%, the vitamin E content is 0.5-2%, and the remainder is sunflower oil. As a specific example, the β-carotene crystals are vitolin (coded SP-HS-CK-01), and the β-carotene oil suspension is vitolin (coded SPHY21-CK-FZ-01).

[0027] Preferably, the antioxidant in step (1) is at least one of tocopherol, sodium vitamin C, sodium citrate, sodium fumarate, sodium tartrate, sodium lactate, and trisodium phosphate.

[0028] Preferably, the cosolvent is selected from at least one of the group consisting of medium-chain triglycerides and vegetable oils (sunflower oil, soybean oil, corn oil, etc.). The medium-chain triglyceride can be octanoic acid glyceride.

[0029] Preferably, the content of the antioxidant in the first oil phase in step (4) is 3 wt%-9 wt%.

[0030] Preferably, the compounded low HLB emulsifier in step (1) is a polyglycerol fatty ester and / or lecithin with an HLB value of 3-9; the content of the polyglycerol fatty ester in the first oil phase is 5wt%-12wt%, and the content of the lecithin in the first oil phase is 18wt%-32wt%; the polyglycerol fatty ester is at least one of triglycerol fatty ester and decaglycerol polyglycerol fatty ester; and the lecithin is at least one of soybean lecithin or sunflower lecithin.

[0031] The present invention utilizes a unique preparation method and employs specific cosolvents, antioxidants, compounded low- and high-HLB emulsifiers, and flavoring substances to significantly enhance the stability of the β-carotene emulsion, resulting in a high-temperature resistant, color-controllable β-carotene emulsion with a unique flavor. The β-carotene emulsion has a wide color range (orange to red), a unique flavor, and exhibits no stratification or precipitation when stored at 120°C for 3 hours. Its high stability meets the needs of diverse downstream applications.

[0032] Preferably, in step (4), the first oil phase contains 7wt%-33wt% of β-carotene crystals or oil suspension, 0wt%-24wt% of vegetable oil, and 0wt%-52wt% of medium-chain triglycerides, and the medium-chain triglyceride and vegetable oil contents are different and are 0wt%.

[0033] Preferably, the vegetable oil is at least one of sunflower oil, soybean oil and corn oil.

[0034] Preferably, the heating temperature in step (1) is 140-150°C.

[0035] Preferably, the compounded high HLB emulsifier in step (2) is a polyglycerol fatty ester with an HLB value of 10-17; the content of the polyglycerol fatty ester in the aqueous phase is 11wt%-24wt%, and the polyglycerol fatty ester is at least one of octapolyglycerol fatty ester and decapolyglycerol monofatty ester.

[0036] Preferably, the content of the co-emulsifier in the aqueous phase in step (2) is 29 wt%-53 wt%, and the co-emulsifier is glycerol.

[0037] Preferably, the content of water in the aqueous phase in step (2) is 34 wt%-60 wt%.

[0038] Preferably, the dissolution temperature in step (2) is not particularly limited and may be within the conventional temperature range for dissolution in the art, such as 55°C-65°C.

[0039] Preferably, the temperature of heating the dissolving kettle in step (4) is 140-150°C.

[0040] Preferably, the liquid level during the dissolution process in step (4) is 5-20 cm higher than the trumpet-shaped inlet of the inlet tube (wherein the trumpet-shaped inlet is located below the liquid level).

[0041] Preferably, the second oil phase in step (5) contains 0.3 wt% to 0.5 wt% of the flavoring agent; the flavoring agent is selected from at least one of dihydroactin, β-ionone, and oxidized isophorone; and the temperature when the flavoring agent is added is 115-120°C.

[0042] The present invention also provides a flavor-enhanced beta-carotene emulsion obtained by the above preparation method.

[0043] The present invention also provides an application of the above-mentioned flavor-enhanced β-carotene emulsion, wherein the flavor-enhanced β-carotene emulsion is used for coloring or / and flavoring beverages, baked foods, and tobacco sheets.

[0044] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0045] The present invention utilizes a specific preparation apparatus, specific cosolvents, antioxidants, a combination of low- and high-HLB emulsifiers, and flavoring substances to control the emulsion particle size and the cis- and trans-isomer ratios of β-carotene. This produces an orange-yellow to red β-carotene emulsion that is heat-resistant (no demulsification, stratification, or precipitation after storage at 120°C for 3 hours) and has a unique flavor. This emulsion can be used in the food and tobacco sectors, particularly for coloring and flavoring beverages, baked goods, and tobacco sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a schematic flow chart of the device and method for preparing the β-carotene emulsion.

[0047] Among them, mark 1-heating kettle; mark 11-feeding port; mark 12-steam inlet; mark 2-dissolving kettle; mark 21-stirring paddle; mark 22-feeding port; mark 23-steam inlet; mark 24-external circulation pipeline; mark 25-emulsification pump; mark 26-inlet pipe; mark 3-emulsification kettle; mark 31-feeding port; mark 32-drinking water inlet; mark 33-stator and rotor shearing mechanism.

[0048] Figure 2 The following are pictures showing the appearance of the emulsions obtained in various embodiments of the present invention and comparative examples before and after heating. DETAILED DESCRIPTION

[0049] The β-carotene emulsion preparation device, formulation, preparation method and application of the present invention are described in detail below.

[0050] Beta-carotene emulsion preparation device of the present invention

[0051] The β-carotene emulsion preparation device of the present invention specifically comprises a heating kettle 1, a dissolving kettle 2, and an emulsifying kettle 3, which are sequentially connected. The bottom of the dissolving kettle 2 is provided with an eccentrically mounted stirring paddle 21; the dissolving kettle is also provided with an external circulation pipeline 24 connecting the liquid phase space and the gas phase space of the dissolving kettle.

[0052] To address the high dissolution temperature and high content of the cis-isomer of β-carotene in the emulsion caused by the hot melt method, the present invention, unlike existing methods, reduces the cis-isomer content of β-carotene by reducing the heating time of the β-carotene. First, a heating kettle is used to heat the solvent to the dissolution temperature, and then the solvent is mixed with the β-carotene crystals or oil suspension for dissolution. This reduces heating time compared to methods that mix the β-carotene crystals or oil suspension with the solvent for dissolution by heating. Second, the eccentrically mounted bottom agitator creates an asymmetric rotating flow field within the dissolution kettle, increasing the relative motion speed between the solvent and the β-carotene crystals, accelerating the surface renewal of the crystals and improving the dissolution rate. Because the bulk density and true density of β-carotene crystals are very low and far less than that of the solvent, after mixing with the solvent, the β-carotene crystals will be suspended on the surface of the solvent. When stirring is activated, the β-carotene crystals rotate around the axis of the agitator. At this time, the β-carotene crystals and the solvent have only minimal relative motion speed, which is the primary factor contributing to the slow dissolution rate of the β-carotene crystals in the solvent. By installing an eccentric bottom agitator, the β-carotene crystals floating on the liquid surface cannot rotate around the axis of the agitator paddle, increasing their relative motion speed with the solvent and improving the dissolution rate. The flow field generated by the eccentric bottom agitator is not a rotating flow field around the axis of the dissolution vessel. Due to the restriction of the bottom head of the vessel, it has a certain tumbling effect, which helps to increase the relative motion speed of the β-carotene crystals and the solvent, thereby improving the dissolution rate.

[0053] Finally, by setting up an external circulation, the turbulence effect in the kettle is enhanced and the dissolution speed is accelerated. The inlet of the external circulation pipeline extends to the interior of the dissolution kettle cavity through an inlet pipe set inside the dissolution kettle, and a trumpet-shaped inlet is provided on the top of the inlet pipe. Such a setting can draw the β-carotene crystals swirling on the liquid surface together with the solvent into the external circulation pipeline through the trumpet mouth. Under the shearing action of the circulation pump, they are further sheared into smaller particles, which can further increase the dissolution speed. Setting up an external circulation pipeline will increase the residual amount of oil phase in the external circulation pipeline. To solve this problem, a nitrogen inlet pipe can be set at the highest point of the external circulation pipeline. After the dissolution is completed, the oil phase in the external circulation pipeline is pressed into the dissolution kettle or the subsequent emulsification kettle by nitrogen to reduce the residue in the external circulation pipeline.

[0054] Formula of the flavor-enhanced beta-carotene emulsion of the present invention

[0055] β-carotene has a bright color, a high color value, and a strong tinting power. Furthermore, β-carotene is an important flavor precursor that degrades under conditions such as light, heat, and oxygen to produce a series of flavor substances, such as dihydroactinolactone (fruity aroma), β-ionone (violet and woody notes), and oxidized isophorone (woody and dried fruit aroma). The β-carotene raw material used in the present invention comprises β-carotene crystals or a β-carotene oil suspension. Preferably, the β-carotene content is 1% to 2.5% by weight, based on the total amount of the β-carotene emulsion.

[0056] The antioxidant of the present invention is not limited and any conventional antioxidant in the art can be used, as long as it can protect the β-carotene, reduce the oxidation rate, and does not destabilize the emulsion. Preferably, the antioxidant is selected from at least one of tocopherol, sodium vitamin C, sodium citrate, sodium fumarate, sodium tartrate, sodium lactate, and trisodium phosphate. To ensure the color stability of the β-carotene emulsion during shelf life, the antioxidant content is preferably 0.5 wt% to 2 wt% based on the total amount of the β-carotene emulsion.

[0057] The cosolvent of the present invention can be any conventional cosolvent in the art. It can shorten the melting time of β-carotene, reduce the ratio of trans-to-cis rearrangement of β-carotene during high-temperature processing, and regulate the color of the emulsion while improving the stability of the β-carotene content in the emulsion. Preferably, the cosolvent is selected from at least one of the group consisting of medium-chain triglycerides and vegetable oils (sunflower oil, soybean oil, corn oil, etc.). Preferably, the cosolvent content is 0% to 20% by weight, based on the total amount of the β-carotene emulsion. More preferably, the vegetable oil content is 0% to 6% by weight, and the medium-chain triglyceride content is 0% to 14% by weight.

[0058] The present invention combines low-HLB and high-HLB polyglycerol fatty esters with lecithin to form a wedge-shaped O / W emulsification on the surface of β-carotene oil droplets, thereby improving the emulsion's emulsification and embedding capacity for β-carotene, thereby enhancing the emulsion's stability and heat resistance. The low-HLB polyglycerol fatty ester of the present invention is a combination of one or more of triglycerol fatty acid esters and decaglycerol fatty acid esters, while the high-HLB polyglycerol fatty ester is a combination of one or more of octaglycerol fatty acid esters and decaglycerol fatty acid esters. Preferably, based on the total amount of the β-carotene emulsion, the polyglycerol fatty ester content is 1wt%-20wt%, and the lecithin content is 3wt%-8wt%. More preferably, the low-HLB polyglycerol fatty ester content is 1wt%-3wt%, and the high-HLB polyglycerol fatty ester content is 10wt%-17wt%.

[0059] Specifically, the low HLB value polyglycerol fatty esters of the present invention are triglycerol dioleate, triglycerol monoricinoleate, triglycerol monooleate, decaglycerol decaoleate, triglycerol diisostearate, and decaglycerol decastearate. The high HLB value polyglycerol fatty esters of the present invention are decaglycerol octanoate, octaglycerol monooleate, decaglycerol monolaurate, decaglycerol monoricinoleate, decaglycerol stearate, and decaglycerol monomyristate.

[0060] The co-emulsifier of the present invention is glycerol. Glycerol adsorbs on the surface of β-carotene, enhancing the adsorption between the β-carotene and the emulsifier and improving emulsification. It also increases the surface smoothness of the β-carotene, increasing light reflection and refraction, boosting the brightness of the emulsion and thus regulating the color of the emulsion. Preferably, the glycerol content is 25% to 40% by weight, based on the total weight of the β-carotene emulsion.

[0061] The present invention optimizes the blending and addition of various flavoring agents, enabling them to exhibit conjugated synergy under certain temperature conditions, significantly enhancing the depth and richness of the aroma and more cleverly reconciling the balance between the various aroma components, thereby imparting a unique flavor to the β-carotene emulsion. Based on aroma synergy, the present flavoring agents are selected from a combination of one or more of dihydroactinolactin, β-ionone, and oxyisophorone. Preferably, the flavoring agent content is 0.075% to 0.1% by weight, based on the total amount of the β-carotene emulsion.

[0062] Preparation method of flavor-enhanced beta-carotene emulsion of the present invention

[0063] The preparation of the beta-carotene emulsion of the present invention comprises the following steps:

[0064] (1) heating a cosolvent, an antioxidant, and a compound low HLB value emulsifier in a heating kettle to obtain a mixed solvent;

[0065] Preferably, the temperature of the heating kettle is set at 140°C-150°C;

[0066] (2) adding a compound high HLB value emulsifier, a co-emulsifier, and water into an emulsifying kettle and dissolving them completely to obtain an aqueous phase;

[0067] Preferably, the temperature of the emulsification kettle is set at 55°C-65°C;

[0068] (3) adding β-carotene crystals or β-carotene oil suspension into the dissolving kettle;

[0069] Preferably, an eccentrically mounted stirring device is provided at the bottom of the dissolving kettle, and an external circulation pipeline is provided to connect the liquid phase space and the gas phase space of the dissolving kettle;

[0070] (4) placing the mixed solvent in the heating kettle into a dissolving kettle to dissolve the β-carotene crystals or the carotene oil suspension to obtain a first oil phase;

[0071] Preferably, the dissolving kettle is set at a temperature range of 140°C-150°C;

[0072] (5) adding a flavoring agent to the dissolving kettle to obtain a second oil phase;

[0073] (6) The second oil phase is added dropwise into the emulsifying kettle and subjected to high-speed shearing to obtain a flavored β-carotene emulsion.

[0074] Preferably, the linear speed of the emulsifying kettle rotor is 9.42-11.80 m / s, the second oil phase addition time is controlled within 30 min, and high-speed shearing is continued for 20 min-35 min after the oil phase is added.

[0075] The method can obtain a flavor-enhanced beta-carotene emulsion with controllable cis-trans forms, controllable particle size and excellent heat resistance.

[0076] application

[0077] The β-carotene emulsion of the present invention can be used in the food and tobacco sectors, and is particularly suitable for coloring and flavoring beverages, baked goods, and tobacco flakes. Prior art β-carotene emulsions have a narrow color controllable range, poor stability at high temperatures (120°C), and are prone to problems such as demulsification and oil slick during downstream processing. The present invention, through the aforementioned device modification and formulation innovation, produces a color-controllable, heat-resistant flavoring β-carotene emulsion that can meet the stringent requirements of beverage and tobacco flake production.

[0078] The following describes a method for testing the properties of the β-carotene emulsion of the present invention.

[0079] Detection of particle size DV(90)

[0080] After diluting the emulsion, a suitable amount was dripped into the sample cell of a Mastersizer-3000 laser particle size analyzer and dispersed with deionized water. The refractive indices of the sample and continuous phase were 1.563 and 1.330, respectively. Measurements were taken when the opacity reached 5% and lasted 30 seconds. Three measurements were taken for each sample, and the results were averaged. D4,3 represents the volume average particle size, while D10, D50, and D90 represent the particle sizes at cumulative distribution percentages of 10%, 50%, and 90%, respectively.

[0081] β-carotene content detection

[0082] Weigh a certain amount of emulsion and place it in a 100mL brown volumetric flask. Add 10mL of water and sonicate for 5min. Add 40mL of anhydrous ethanol and 40mL of chloroform and sonicate for another 5min. Remove and cool, dilute to the mark with anhydrous ethanol, shake well, draw 2.0mL into a 50mL brown volumetric flask, blow dry the solvent in the flask with nitrogen, then dissolve it in cyclohexane and dilute to the mark, shake well, and measure the absorbance at 455nm:

[0083]

[0084] Where X1 represents the mass percentage of β-carotene in the sample, A represents the absorbance of the test solution at 455 nm, m represents the sample weight, 2500 (in the numerator) represents the volume dilution factor of the sample, and 2500 (in the denominator) represents the percentage absorbance coefficient of β-carotene (E 1CM 1%).

[0085] β-carotene cis-trans detection

[0086] Weigh a certain amount of the emulsion into a 250mL brown volumetric flask, add 100mL of anhydrous ethanol and 100mL of dichloromethane, then sonicate in a 60°C waterbath for 10 minutes. Cool to room temperature, dilute to volume with dichloromethane, and shake well. Liquid chromatography conditions: C30 column, 5µm, 250mm×4.6mm; mobile phase: methanol:isopropanol:dichloromethane = 3:1:1; flow rate: 1.0mL / min; injection volume: 20µL; detection wavelength: 450nm; column temperature: 30°C. The standard solution and sample solution were collected, filtered through a 0.45µm organic filter membrane, and analyzed according to the chromatographic conditions. Peak areas were calculated to determine the ratios of all-trans, 9-cis, 13-cis, 15-cis, 9,13-bis-cis, and 9,15-bis-cis in the emulsion.

[0087] Chromatic Aberration

[0088] After the black and white calibration, the color difference between the emulsion itself and the aqueous solution (120 ppm) was measured using a 3nh YS3010 colorimeter. The measurement was repeated 5 times for each sample to obtain the average value.

[0089] High temperature stability

[0090] Pour approximately 2 mL of the emulsion into a 15 mL centrifuge tube, cover, and place in a DDG-9240B electric constant-temperature forced-air drying oven at 120°C for 3 hours. Remove the tube and observe for oily residues, precipitation, or stratification, taking photos. Appropriately dilute the emulsion before and after the 3-hour incubation at 120°C. Prepare slides and observe microscopic images using an OLYMPUS optical microscope at 400x magnification.

[0091] Emulsion stability index (TSI value)

[0092] The physical stability of emulsions is measured using a Formulaaction Turbiscan stability analyzer. The Turbiscan uses near-infrared light as a light source and has both transmitted light and backscattered light detectors. The measuring probe measures every 20 μm from the bottom to the top of the sample cell, and a complete bottom-to-top measurement is called a scan. Over time, both transmitted and backscattered light change, indicating changes in the sample's particle size and concentration. For emulsion systems, backscattered light intensity (BS) is an evaluation metric. Using the initial sample as a reference, BS at different times reflects changes in the system. TSI can comprehensively reflect changes in the emulsion's properties:

[0093] TSI=∑i(∑_h|scan_i-scan_(i-1)(h)|) / H

[0094] In the formula, scani(h) is the backscattered light intensity of the sample at position h in the i-th scan; scani-1(h) is the backscattered light intensity of the sample at position h in the i-1-th scan; and H is the sample height.

[0095] Transfer 20 mL of the emulsion into a sample bottle. The emulsion should not adhere to the wall. The measurement parameters are: temperature 60°C, scanning frequency 15 min / time, and analysis time 8 h. Obtain the stability index (TSI) and the corresponding curve.

[0096] The present invention is further described below with reference to specific embodiments.

[0097] Example 1

[0098] Heating process:

[0099] Add 2.5 kg of tocopherol, 40.0 kg of octanoic acid glyceryl, 2.5 kg of triglycerol dioleate, 2.5 kg of triglycerol monoricinoleate, and 15.0 kg of sunflower lecithin to the kettle through the feed port. Fill the kettle with nitrogen to displace the air. Start stirring, open the steam inlet valve on the kettle jacket, and heat the contents to 140°C.

[0100] Aqueous phase preparation:

[0101] Open the drinking water inlet valve on the emulsifier and add 242.65 kg of drinking water to the emulsifier. Add 30.0 kg of polyglycerol octanoate, 20.0 kg of polyglycerol octanoate, and 125.0 kg of glycerol through the feed port. Start stirring. Open the hot water inlet valve on the emulsifier jacket and introduce 60°C hot water into the jacket to dissolve the mixture. When the temperature inside the emulsifier reaches 55°C, keep it warm and set aside.

[0102] Dissolution process:

[0103] Add 19.5 kg of a 30% β-carotene oil suspension (Carvisol, code SPHY21-CK-FZ-01) (UV content: 30.8%, liquid chromatography analysis: all-trans content: 96.2%, cis content: 3.7%) to the dissolving vessel through the feed port. Nitrogen is then introduced into the dissolving vessel to displace the air. Open the steam inlet valve to the dissolving vessel jacket and set the temperature to 140°C to preheat the equipment. Open the bottom valve of the heating vessel and add the high-temperature material from the heating vessel to the dissolving vessel. Start stirring at the bottom of the dissolving vessel, ensuring that the flared inlet of the feed pipe is approximately 10 cm below the liquid surface. The β-carotene rotates near the top of the flared inlet of the feed pipe. Start the external circulation emulsification pump to perform shear emulsification. The β-carotene oil suspension is drawn into the emulsification pump, where it rapidly dissolves under the high-speed shear of the emulsification pump rotor and returns to the dissolving vessel. After the β-carotene is completely dissolved, 0.375 kg of isophorone oxide is added and continues to dissolve rapidly under the high-speed shear of the emulsification pump rotor. The time from the completion of discharge to the completion of dissolution is 60 seconds. The material in the dissolution kettle is quickly placed into the emulsification kettle. The nitrogen inlet valve on the external circulation pipeline is opened, and nitrogen is used to press the material inside the external circulation pipeline and the emulsification pump into the emulsification kettle for emulsification.

[0104] emulsification:

[0105] While the material in the dissolving kettle is being placed into the emulsifying kettle, the stator and rotor shear mechanism of the emulsifying kettle is turned on, and the rotor linear speed is set to 9.42 m / s. The high-speed shearing emulsification is carried out for 30 minutes under the condition of controlling the internal temperature at 55°C.

[0106] The β-carotene emulsion of the present invention can be prepared by the above method. The particle size, content, cis-trans form and color difference of the β-carotene emulsion are shown in Table 1.

[0107] Example 2

[0108] Example 2 The heating temperature in the heating kettle was increased to 150° C. The other process devices and parameters were the same as those in Example 1. A β-carotene emulsion was prepared according to the formula shown in Table 1. The content (mass %) of the components was based on the total amount of the β-carotene emulsion. The parameters of the prepared emulsion are shown in Table 1.

[0109] Examples 3 to 5

[0110] In the process apparatus of Examples 3 to 5, the trumpet-shaped inlet of the feed pipe was set 5 cm below the material liquid surface. Other process parameters were consistent with those of Example 1. β-carotene emulsions were prepared according to the formulation shown in Table 1. The content (mass %) of the components was based on the total amount of the β-carotene emulsion. The parameters of the prepared emulsions are shown in Table 1.

[0111] Table 1

[0112]

[0113]

[0114] *The β-carotene content in the formulas in Table 1 refers to the total mass of β-carotene crystals or β-carotene oil suspension.

[0115] As can be seen from the data in Table 1, a β-carotene emulsion can be obtained according to the formulations and processes of Examples 1 to 5. The dissolution process takes between 30 seconds and 60 seconds, the particle size Dv(90) is between 0.28 μm and 0.39 μm, the all-trans content is between 85% and 93%, the cis content is between 7% and 15%, the color difference L value is between 30 and 40, the color difference a value is between 20 and 26, and the color difference b value is between 20 and 30. When the emulsion is observed under a microscope, no crystals are precipitated within the field of view of 400 times magnification.

[0116] Comparative Example 1

[0117] In the process apparatus of Comparative Example 1, the trumpet-shaped inlet of the feed pipe was set 20 cm below the material liquid surface, and other process parameters were the same as those of Example 1. The content (mass %) of the components was calculated based on the total amount of the β-carotene emulsion. The parameters of the prepared emulsion are shown in Table 2.

[0118] Comparative Example 2

[0119] In Comparative Example 2, the heating temperature was lowered to 120° C., and other process devices and parameters were the same as those in Example 1. The contents (mass %) of the components were calculated based on the total amount of the β-carotene emulsion. The parameters of the prepared emulsion are shown in Table 2.

[0120] Comparative Example 3

[0121] The process equipment and process parameters of Comparative Example 3 are basically the same as those of Example 1, except that the circulating emulsification pump is not opened for dissolution, and the content (mass %) of the components is calculated based on the total amount of the β-carotene emulsion. The parameters of the prepared emulsion are shown in Table 2.

[0122] Comparative Example 4

[0123] The process equipment and process parameters of Comparative Example 4 were substantially the same as those of Example 1, except that the β-carotene crystals, tocopherol, octanoic acid glycerol, low-HLB polyglycerol fatty acid ester, and lecithin were all placed in a dissolution kettle for heating and dissolution, and the external circulation emulsification pump was not operated during the dissolution process. The component contents (mass %) were calculated based on the total amount of the β-carotene emulsion. The parameters of the prepared emulsion are shown in Table 2.

[0124] Table 2

[0125]

[0126]

[0127] As can be seen from the data in Table 2, although the formulas of Comparative Examples 1 to 4 are consistent with those of Example 1, due to changes in the process equipment, heating temperature, emulsification method or dissolution method, the emulsion dissolution process of the preparation takes 90 seconds to 15 minutes and 45 seconds, the all-trans content is between 44% and 87%, and the cis content is between 13% and 56%. The emulsion color difference distribution is very narrow, with an L value of 34-38, a color difference a value of 19-23, and a color difference b value of 24-27. When the emulsion is observed under a microscope, crystallization is observed within the 400-fold magnification field, and the emulsion has a demulsification phenomenon. The experimental results show that the device and process of the present invention can greatly improve the all-trans ratio in the emulsion and can better control the emulsion color difference distribution range.

[0128] Comparative Examples 5 to 8

[0129] The same preparation apparatus and preparation process as in Example 1 were used to prepare a β-carotene emulsion according to the formula shown in Table 3. The contents (mass %) of the components were calculated based on the total amount of the β-carotene emulsion. The parameters of the prepared emulsion are shown in Table 3.

[0130] Table 3

[0131]

[0132]

[0133] The data in Table 3 show that although the preparation apparatus and process of Comparative Examples 5-8 were identical to those of Example 1, the addition of only low-HLB polyglycerol fatty acid esters, only high-HLB polyglycerol fatty acid esters, or only lecithin resulted in significantly increased particle size in the resulting β-carotene emulsions. Microscopic observation revealed demulsification in all emulsions, indicating extreme instability. These experimental results demonstrate that only by combining specific emulsifiers in specific ratios can a stable β-carotene emulsion with a wide color range be prepared.

[0134] The present invention also carried out emulsion thermal stability index and heat resistance test on the β-carotene emulsions of Examples 1 to 5 and Comparative Examples 5 to 8 to investigate the effect of temperature on the stability of the β-carotene emulsions, as shown in Tables 4 and Figure 2 middle.

[0135] Table 4

[0136]

[0137]

[0138] Table 4 and Figure 2 As can be seen, after heating at 120°C for 3 hours, the emulsions of Examples 1-5 showed no delamination or precipitation, indicating that the emulsions maintained good heat resistance. Furthermore, the emulsion stability index (TSI) values ​​of Examples 1-5 were very low, demonstrating that the β-carotene emulsions of the present invention possess excellent stability. However, after heating at 120°C for 3 hours, the emulsions of Comparative Examples 5-8 exhibited obvious delamination, with the appearance of black circles, and had very high TSI values, indicating poor heat resistance and emulsion stability.

Claims

1. A device for preparing β-carotene emulsion, characterized in that: It includes a heating kettle, a dissolving kettle and an emulsifying kettle which are connected in sequence; An eccentrically mounted stirring paddle is provided at the bottom of the dissolving kettle; The dissolving kettle is further provided with an external circulation pipeline communicating with the liquid phase space and the gas phase space of the dissolving kettle, and a circulation pump is provided on the external circulation pipeline.

2. The preparation device according to claim 1, characterized in that The inlet of the external circulation pipeline is arranged on the other side of the lower part of the dissolving kettle opposite to the stirring paddle, and the outlet of the external circulation pipeline is arranged on the upper part of the dissolving kettle; The inlet of the external circulation pipeline extends to the interior of the dissolving kettle cavity through an inlet pipe arranged inside the dissolving kettle, and a trumpet-shaped inlet is provided on the top of the inlet pipe.

3. A method for preparing a flavored β-carotene emulsion, characterized in that: The preparation is carried out using the preparation device according to claim 1 or 2, comprising the following steps: (1) heating a cosolvent, an antioxidant, and a compound low HLB value emulsifier in a heating kettle to obtain a mixed solvent; (2) adding a compound high HLB value emulsifier, a co-emulsifier, and water into an emulsifying kettle and dissolving them completely to obtain an aqueous phase; (3) adding β-carotene crystals or β-carotene oil suspension into the dissolving kettle; (4) placing the mixed solvent in the heating kettle into a dissolving kettle to dissolve the β-carotene crystals or the β-carotene oil suspension to obtain a first oil phase; (5) adding a flavoring agent to the dissolving kettle to obtain a second oil phase; (6) The second oil phase is added to an emulsifying kettle to contact with the water phase, and a flavored β-carotene emulsion is obtained by high-speed shearing.

4. The preparation method according to claim 3, characterized in that In step (1), the antioxidant is at least one of tocopherol, sodium vitamin C, sodium citrate, sodium fumarate, sodium tartrate, sodium lactate, and trisodium phosphate; The cosolvent is selected from at least one of medium chain triglycerides and vegetable oils; The vegetable oil is preferably at least one of sunflower oil, soybean oil, and corn oil; The compound low HLB value emulsifier is polyglycerol fatty ester and / or lecithin with an HLB value of 3-5; The polyglycerol fatty ester is preferably at least one of triglycerol fatty ester and decaglycerol fatty ester; The lecithin is preferably at least one of soybean lecithin or sunflower lecithin; The heating temperature in step (1) is 140-150°C.

5. The preparation method according to claim 3 or 4, characterized in that The content of the antioxidant in the first oil phase is 0.5 wt % to 2 wt %. The content of the polyglycerol fatty ester in the first oil phase is 1wt%-3wt%; The content of the lecithin in the first oil phase is 3wt%-8wt%; The first oil phase further contains 1 wt%-2 wt% of beta-carotene, 0 wt%-6 wt% of vegetable oil, and 0 wt%-14 wt% of medium-chain triglycerides, and the content of medium-chain triglycerides and vegetable oil is 0 wt% when the content is different.

6. The preparation method according to claim 3, characterized in that In step (2), the composite high-low HLB value emulsifier is a polyglycerol fatty ester with an HLB value of 10-17, preferably at least one of octapolyglycerol fatty ester and decapolyglycerol fatty ester; The content of the polyglycerol fatty ester in the aqueous phase is 10wt%-17wt%; The auxiliary emulsifier is glycerol, and the content of the auxiliary emulsifier in the water phase is 25 wt%-40 wt%.

7. The preparation method according to claim 3, characterized in that In step (4), the liquid level during the dissolution process exceeds the trumpet-shaped inlet of the inlet tube by 5-20 cm.

8. The preparation method according to claim 3, characterized in that In step (5), the second oil phase contains 0.075 wt% to 0.1 wt% of the flavoring agent; The flavoring agent is selected from at least one of dihydroactin, β-ionone, and oxidized isophorone; The temperature when adding the flavoring agent is 115-120℃.

9. A flavored β-carotene emulsion obtained by the preparation method according to any one of claims 3 to 8.

10. Use of the flavored β-carotene emulsion according to claim 9, characterized in that: The flavor-enhanced beta-carotene emulsion is used for coloring or / and flavoring beverages, baked foods, and tobacco sheets.

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