A high all-trans carotenoid microcapsule and a method for preparing the same

Abstract

The present application belongs to the field of microcapsule preparation, and relates to a kind of high all-trans carotenoid microcapsule and its preparation method.The preparation method of the high all-trans carotenoid microcapsule includes high-temperature melting of an oil phase containing carotenoid, carrier oil and emulsifier, shearing emulsification of the obtained carotenoid oil solution and wall material aqueous phase, and then spray drying after isomerization treatment of the obtained emulsion with Blakeslea trispora fermentation enzyme solution, to obtain the high all-trans carotenoid microcapsule.In the present application, the emulsion is subjected to isomerization treatment with Blakeslea trispora fermentation enzyme solution before spray drying, which can significantly increase the content of all-trans structure in carotenoid microcapsule, avoid the use of high-toxicity organic solvents in the production process, reduce the harmful factors to workers' health in the production process, improve product quality, and has wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microcapsule preparation, and particularly relates to a high all-trans carotenoid microcapsule and a preparation method thereof. BACKGROUND

[0002] Carotenoids exist widely in nature, and play the role of vitamin A source or antioxidant in human body, and are widely used in food, feed, health products, medicine and other industries. Since carotenoids are not soluble in water and sensitive to light, they are usually prepared into microcapsules to improve their bioavailability, but their solubility in oil is also very small, and they are easily converted from all-trans isomers to cis isomers under heat, and the bioavailability of all-trans isomers of most carotenoids is much higher than that of cis isomers, so how to reduce the loss of carotenoids during microencapsulation and maintain a good cis-trans ratio has become an important research topic.

[0003] At present, the methods for producing carotenoid microcapsules mainly include solvent method and melting method. For example, US3998753A discloses a method for preparing carotenoid microcapsules by solvent method, which dissolves carotenoids in an organic solvent, then adds the organic solvent into an aqueous solution containing gelatin, emulsifier and the like, forms an emulsion by high-speed shearing, and then sprays and dries the organic solvent in the emulsion to obtain the desired powder. Although this method can reduce the isomerization of carotenoids to obtain high all-trans carotenoid microcapsules, a large amount of organic solvent is needed in the whole process, and the organic solvent is difficult to remove safely, and there is still residual in the final product. CN105878211A discloses a method for preparing carotenoid microcapsules by melting method, which includes grinding carotenoids in methyl oleate by a ball mill, then feeding into a spiral heat conduction pipe to disperse at 210℃, then emulsifying in an aqueous phase prepared from lignin sulfonate and water, and then spraying and drying to obtain the desired product. Although this method can avoid the use of organic solvents with high toxicity, it needs to use a ball mill, which has high energy consumption, and at the same time, carotenoids will be converted from all-trans to cis isomers during high-temperature heating, so the final product has a high proportion of cis structure of carotenoids, which is not conducive to the improvement of bioavailability. SUMMARY

[0004] The purpose of the present application is to overcome the defect that the content of all-trans isomer carotenoids in carotenoid microcapsules obtained by the existing melting method is low, and to provide a high all-trans carotenoid microcapsule and a preparation method thereof.

[0005] Specifically, the application provides a preparation method of high all-trans carotenoid microcapsules, which comprises the following steps: high-temperature melting of an oil phase containing carotenoids, carrier oil and emulsifier, shearing emulsification of the obtained carotenoid oil solution and a water phase containing wall material, and spray drying of the obtained emulsion after isomerization treatment by using a fermentation enzyme solution of Blakeslea trispora.

[0006] The inventors of the application surprisingly find that the fermentation enzyme solution of Blakeslea trispora can realize the transformation of carotenoids from cis to all-trans, and the emulsion is subjected to isomerization treatment by using the fermentation enzyme solution of Blakeslea trispora before spray drying on the basis of the melting method, so that the content of all-trans structure in the carotenoid microcapsules can be significantly improved, the use of high-toxicity organic solvents in the production process can be avoided, the harm factors to the health of workers in the production process are reduced, the product quality is improved, and the application prospect is wide.

[0007] In a preferred embodiment, the high-temperature melting conditions comprise a temperature of 150-190 DEG C and a time of 3-10 s, and the oil phase is subjected to melting by using this instantaneous heating mode, so that the isomerization of carotenoids can be avoided from being intensified, and the all-trans content in the carotenoid microcapsules can be more favorably improved. DETAILED DESCRIPTION

[0008] The preparation method of the high all-trans carotenoid microcapsules provided by the application comprises the following steps: melting of an oil phase containing carotenoids, carrier oil and emulsifier, shearing emulsification of the obtained carotenoid oil solution and a water phase containing wall material, and spray drying of the obtained emulsion after isomerization treatment by using a fermentation enzyme solution of Blakeslea trispora. The isomerization of carotenoids by using the fermentation enzyme solution of Blakeslea trispora can effectively convert the cis isomerized carotenoids in the system into all-trans, solves the inevitable isomerization problem in the preparation process of the carotenoid emulsion, improves the product quality, and has great advantages in the actual production process, because the reaction conditions are mild, the energy consumption is low, the pollution is small, there is no residue of high-toxicity additives.

[0009] The source of the Blakeslea trispora fermentation enzyme liquid is not particularly limited in the present application, and can be obtained by commercial purchase or prepared according to various existing methods. In a preferred embodiment, the Blakeslea trispora fermentation enzyme liquid is prepared according to the following method: positive and negative strains of Blakeslea trispora are inoculated into slant medium respectively and cultured until spores are produced, the obtained positive and negative spores are inoculated into seed culture medium respectively for seed culture, the obtained positive and negative seed liquids are inoculated into fermentation culture medium for fermentation culture, followed by solid-liquid separation, the obtained solid is crushed and dissolved with buffer solution, and then subjected to solid-liquid separation, and the obtained filtrate is the Blakeslea trispora fermentation enzyme liquid. In the fermentation culture process, the mass ratio of the positive and negative seed liquids is preferably 1:(5-15). The total inoculation amount of the positive and negative seed liquids is preferably 10-20%. The culture conditions in the slant medium are preferably 25-35°C for 1-10 days. The seed culture conditions are preferably 25-35°C, 100-300 r / min for 20-40 h to reach the logarithmic phase. The fermentation culture conditions are preferably 25-35°C, pH 6.5-7.5, 100-300 r / min for 50-80 h. In addition, the slant medium preferably contains 1000 mL of potato extract, 10-30 g of glucose and 10-30 g of agar powder. The seed culture medium preferably contains 10-40 g of glucose, 20-35 g of soybean protein powder, 0.5-1 g of magnesium sulfate, 1-5 g of potassium dihydrogen phosphate, 0.01-0.5 g of calcium chloride, 0.01-0.5 g of copper sulfate, 0.01-0.1 g of VE and 0.1-1 g of Tween. The fermentation culture medium preferably contains 0.05-0.5 L of starch hydrolysate, 5-20 g of soybean protein powder, 20-35 g of fish meal, 10-30 g of corn oil, 0.01-0.5 g of copper sulfate, 0.1-2 g of magnesium sulfate, 1-5 g of potassium dihydrogen phosphate, 0.01-0.1 g of VE, 0.1-1 g of Tween. Furthermore, the solid obtained after solid-liquid separation of the fermentation culture product is wet mycelium, and the method for crushing the wet mycelium can be, for example, ball milling. The rotation speed of the ball milling is generally 50-200 r / min. Specific examples of the buffer solution include, but are not limited to, at least one of phosphate buffer, ammonia-ammonium chloride buffer, acetic acid-sodium acetate buffer, acetic acid-ammonium acetate buffer, etc. The pH value of the buffer solution is preferably 6.5-7.5. The weight ratio of the wet mycelium to the buffer solution is preferably 100:(10-30).The amount of the fermentation enzyme solution of Blakeslea trispora is preferably 0.3 to 0.6 times the mass of the carotenoid, such as 0.30, 0.32, 0.35, 0.38, 0.40, 0.42, 0.45, 0.48, 0.50, 0.52, 0.55, 0.58, 0.60 times or any value therebetween.

[0010] The present application does not have a particular limitation on the type of carotenoid, and specific examples thereof include, but are not limited to, at least one of β-carotene, lycopene, canthaxanthin, astaxanthin, and lutein.

[0011] In the present application, the carrier oil functions to suspend and disperse the carotenoid. The carrier oil can be at least one of animal oil, vegetable oil, and fatty acid ester. Among them, the animal oil and the vegetable oil can both be natural, or can be after structural modification, hydrolysis, or a mixture of both, and can be at least one selected from the group consisting of soybean oil, rapeseed oil, olive oil, sesame oil, corn oil, palm oil, sunflower oil, mustard oil, rice bran oil, coconut oil, flaxseed oil, evening primrose oil, garlic oil, jojoba oil, lard, beef tallow, fish oil, butter, and the like. The fatty acid ester can be a medium-chain triglyceride, and is preferably at least one selected from the group consisting of caproic acid triglyceride, caprylic acid triglyceride, capric acid triglyceride, caprylic acid capric acid glyceride (MCT), heptanoic acid triglyceride, and lauric acid triglyceride, and more preferably caprylic acid triglyceride and / or capric acid triglyceride. In addition, the amount of the carrier oil is preferably 0.8 to 1.7 times the mass of the carotenoid, such as 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 times or any value therebetween.

[0012] In the present application, the emulsifier functions to form a stable emulsion during the microencapsulation process. Specific examples of the emulsifier include, but are not limited to, at least one of Tween, glycerol ester, lecithin, and sucrose fatty acid ester. The Tween can be, for example, at least one selected from the group consisting of Tween 20, Tween 21, Tween 40, Tween 60, Tween 61, Tween 80, Tween 81, Tween 85, and the like. The glycerol ester can be, for example, at least one selected from the group consisting of stearic acid monoglyceride, lauric acid monoglyceride, citric acid monoglyceride, succinic acid monoglyceride, oleic acid monoglyceride, palmitic acid monoglyceride, and the like. The sucrose fatty acid ester can be, for example, at least one selected from the group consisting of sucrose acetate isobutyrate, sucrose laurate, and the like. In addition, the amount of the emulsifier is preferably 0.01 to 0.03 times the mass of the carotenoid, such as 0.01, 0.02, 0.03 times or any value therebetween.

[0013] In the present application, the wall material is preferably at least one selected from the group consisting of modified starch, proteinaceous compound wall material and carbohydrate wall material. Among them, the modified starch is preferably at least one selected from the group consisting of acid modified starch, octenyl succinate starch, sodium octenyl succinate starch, oxidized starch, acetic ester starch, hydroxypropyl starch and pregelatinized starch. The proteinaceous compound wall material is preferably at least one selected from the group consisting of whey protein, sodium caseinate and soybean protein isolate. The carbohydrate wall material is preferably at least one selected from the group consisting of gum arabic, white sugar, cyclodextrin, malt dextrin, white sugar, solid corn syrup and glucose syrup dry powder. These wall materials can be commercially available or prepared by existing methods, the specific preparation process is known to those skilled in the art, which is not described here. The amount of the wall material is preferably 3-9 times the mass of carotenoids, such as 3, 4, 5, 6, 7, 8, 9 times or any value between them.

[0014] In the present application, the oil phase also preferably contains an antioxidant, which can effectively prevent the oxidation of the active ingredient, thereby improving the activity of the final high all-trans carotenoid microcapsule. Specific examples of the antioxidant include, but are not limited to, at least one of dibutylhydroxytoluene, tert-butyl hydroquinone, butylated hydroxyanisole, alpha-tocopherol, gallate, p-hydroxybenzoic acid ester, ascorbic acid palmitate, rosemary extract and tea polyphenol. In addition, the amount of the antioxidant is preferably 0.1-0.6 times the mass of carotenoids, such as 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60 times or any value between them.

[0015] In the present application, the oil phase contains carotenoids, carrier oil and emulsifier, and optionally an antioxidant. In the preparation of the oil phase, the above materials can be mixed uniformly in any order, for example, carotenoids, emulsifier and optional antioxidant can be dispersed in the carrier oil to obtain.

[0016] The present application does not have a particular limitation on the high-temperature melting conditions, as long as the carotenoids and emulsifier and optional antioxidant can be completely melted in the carrier oil, preferably including a temperature of 150-190°C, such as 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C or any value between them; time is 3-10 s, such as 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, 9 s, 10 s or any value between them. Under the above preferred conditions, high-temperature melting can maximize the avoidance of the conversion of all-trans carotenoids to cis, and is more conducive to the improvement of the all-trans content in the carotenoid microcapsule.

[0017] The isomerization treatment is not particularly limited in the present application, as long as the carotenoids in the emulsion can be converted from cis to all-trans. Preferably, the isomerization treatment comprises a temperature of 25-30°C, such as 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, or any value therebetween; and a time of 1-5h, such as 1h, 2h, 3h, 4h, 5h, or any value therebetween.

[0018] Preferably, the method for preparing the high all-trans carotenoid microcapsule further comprises adding a reducing agent before and / or during the isomerization treatment. In this case, the oxidized active ingredient in the emulsion can be reduced, further improving the activity of the high all-trans carotenoid microcapsule obtained finally. Specific examples of the reducing agent include, but are not limited to, at least one of sodium sulfite, sodium thiosulfate, and sodium hydrosulfite. In addition, the amount of the reducing agent is preferably 0.01-0.04 times the mass of the carotenoid, such as 0.010, 0.012, 0.015, 0.018, 0.020, 0.022, 0.025, 0.028, 0.030, 0.032, 0.035, 0.038, 0.040 times, or any value therebetween.

[0019] The present application also provides a high all-trans carotenoid microcapsule prepared by the above method.

[0020] The present application will be described in detail below by way of examples. The examples are intended to illustrate the present application, and should not be construed as limiting the present application. If a specific technique or condition is not specified in the examples, the technique or condition described in the literature in the art or according to the product manual is used. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be obtained commercially.

[0021] In the following examples and comparative examples:

[0022] The content of carotenoids is detected by a liquid chromatograph (Agilent 1200), wherein the chromatographic column is a Dalian Yili Hypersil ODS2 5um×4.6mm×250mm, the detector is a UV, the wavelength is 465nm, the column temperature is 25°C, the flow rate is 1.0mL / min, the mobile phase is acetonitrile:water:n-pentanol (V:V:V) = 92:7:1, and the injection volume is 10.0μL. The content of all-trans is obtained by the peak area ratio.

[0023] Preparation Example 1: Method for preparing enzyme solution

[0024] The positive and negative strains of Blakeslea trispora were inoculated on slant medium under sterile conditions and cultured in an incubator at 28°C for 5 days. After the positive and negative strains grew spores, the positive and negative spores were inoculated into seed medium under sterile conditions and cultured at 28°C and 200 r / min for 28 h. The logarithmic phase positive and negative strains were inoculated into fermentation medium at a weight ratio of 1:9 and a 15% inoculation amount, and cultured at 28°C, pH 7.0, and 200 r / min for 60 h. After the culture, the culture was filtered with gauze, the wet mycelium was ball-milled at 100 r / min for 1 h to break the mycelium, then washed with phosphate buffer (pH 7.2, the weight ratio of wet mycelium to buffer was 100:20) and centrifuged at 100 g for 10 min. The obtained supernatant was Blakeslea trispora fermentation enzyme liquid.

[0025] The slant medium was composed of potato extract 1000 mL, glucose 20 g, and agar powder 20 g.

[0026] The seed medium was composed of glucose 22 g, soybean protein powder 26 g, magnesium sulfate 0.8 g, potassium dihydrogen phosphate 3 g, calcium chloride 0.06 g, copper sulfate 0.06 g, VE 0.025 g, and Tween-60 0.5 g.

[0027] The fermentation medium was composed of starch hydrolysate 0.2 L, soybean protein powder 12 g, fish meal 26 g, corn oil 20 g, copper sulfate 0.06 g, magnesium sulfate 0.8 g, potassium dihydrogen phosphate 3 g, VE 0.025 g, and Tween-60 0.5 g.

[0028] Example 1

[0029] Example 1

[0030] Example 2

[0031] Example 3

[0032] Example 4

[0033] Aqueous phase was prepared by dissolving 13.3 g of sodium octenyl succinate starch, 9.1 g of maltodextrin, 9.1 g of white sugar in 28 g of water. Oil phase was prepared by dispersing 5.2 g of astaxanthin (45.66% of all-trans content), 0.15 g of sucrose laurate, 2 g of α-tocopherol in 7.7 g of caprylocapryl acid glyceride, and then the mixture was heated in a screw-heated tube at 180 °C for 10 s to dissolve astaxanthin completely. The astaxanthin oil solution was added to the aqueous phase and emulsified at 60 °C and 10,000 rpm for 10 min by using a shearing machine to obtain a homogeneous emulsion. After the emulsion was cooled to 28 °C, 2 g of the enzyme solution prepared in Preparation Example 1 and 0.1 g of sodium dithionite were added, and the mixture was incubated at 28 °C for 3 h. Then, the mixture was heated to 60 °C and spray-dried to obtain powdered astaxanthin microcapsules. The astaxanthin content of the powdered astaxanthin microcapsules was 10.10% and the all-trans content was 88.24% as determined by HPLC.

[0034] Example 4

[0035] Aqueous phase was prepared by dissolving 24 g of sodium octenyl succinate starch, 19 g of maltodextrin, 29 g of white sugar in 68 g of water. Oil phase was prepared by dispersing 10.5 g of all-trans lycopene, 0.2 g of Tween 80, 2 g of tert-butyl hydroquinone in 8.7 g of soybean oil, and then the mixture was heated in a screw-heated tube at 150 °C for 10 s to dissolve lycopene completely. The lycopene oil solution was added to the aqueous phase and emulsified at 60 °C and 10,000 rpm for 10 min by using a shearing machine to obtain a homogeneous emulsion. After the emulsion was cooled to 28 °C, 6 g of the enzyme solution prepared in Preparation Example 1 and 0.24 g of sodium sulfite were added, and the mixture was incubated at 28 °C for 3 h. Then, the mixture was heated to 60 °C and spray-dried to obtain powdered lycopene microcapsules. The lycopene content of the powdered lycopene microcapsules was 10.18% and the all-trans content was 95.74% as determined by HPLC.

[0036] Example 5

[0037] Example 1

[0038] Examples 6-12

[0039] β-carotene microcapsules were prepared according to the method of Example 1, except that the amount of enzyme solution and sodium hydrosulfite was adjusted according to Table 1, and the other conditions were the same as in Example 1. The content of β-carotene and all-trans in the β-carotene microcapsules is shown in Table 1.

[0040] Table 1

[0041] Example Enzyme solution (g) Sodium hydrosulfite (g) Beta-carotene content (%) All-trans content (%) Example 6 3 0.1 10.24％ 94.52％ Example 7 3 0.15 10.12％ 94.85％ Example 8 2.5 0.1 9.88％ 95.11％ Example 9 2.5 0.15 10.30％ 95.78％ Example 10 2.5 0.2 9.98％ 93.89％ Example 11 2 0.15 9.87％ 94.21％ Example 12 2 0.2 10.17％ 95.66％

[0042] Example 13

[0043] β-carotene microcapsules were prepared according to the method of Example 1, except that the high-temperature melting conditions included a temperature of 130°C and a time of 10 min, and the other conditions were the same as in Example 1. The content of β-carotene in the powder β-carotene microcapsules was 8.84%, and the content of all-trans was 68.45%, as determined by HPLC.

[0044] Example 14

[0045] β-carotene microcapsules were prepared according to the method of Example 1, except that α-tocopherol was not added to the oil phase, and the other conditions were the same as in Example 1. The content of β-carotene in the powder β-carotene microcapsules was 8.36%, and the content of all-trans was 95.22%, as determined by HPLC.

[0046] Example 15

[0047] The β-carotene microcapsules were prepared according to the method of Example 1, except that sodium hydrosulfite was not added to the emulsion, and the other conditions were the same as in Example 1, to obtain the powder β-carotene microcapsules. HPLC detection showed that the content of β-carotene in the powder β-carotene microcapsules was 9.03%, and the content of all-trans was 56.24%.

[0048] Comparative Example 1

[0049] The β-carotene microcapsules were prepared according to the method of Example 1, except that the emulsion was not subjected to isomerization treatment with enzyme solution, and the specific steps were as follows:

[0050] The following were dissolved in 19 g of water to obtain the water phase: 12.6 g of sodium octenyl succinate starch, 9.1 g of maltodextrin, and 9.8 g of white sugar. The following were dispersed in 7.7 g of caprylocaproyl glycerides to obtain the oil phase: 5.2 g of all-trans β-carotene, 0.05 g of lecithin, and 2 g of α-tocopherol. The β-carotene oil solution was obtained by heating the mixture in a screw-heated tube at 170°C for 7 s. The β-carotene oil solution was added to the water phase, and the mixture was emulsified at 60°C and 10,000 rpm for 10 min using a shearing machine to obtain a uniformly mixed emulsion. The emulsion was mixed with 0.1 g of sodium hydrosulfite, and the mixture was heated to 60°C for spray drying to obtain the powder β-carotene microcapsules. HPLC detection showed that the content of β-carotene in the powder β-carotene microcapsules was 7.68%, and the content of all-trans was 55.57%.

[0051] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements, and variations to the above embodiments without departing from the principles and spirit of the present application within the scope of the present application.

Claims

1. A method for preparing high-all-trans-carotenoid microcapsules, characterized in that, The method involves melting an oil phase containing carotenoids, carrier oil, and emulsifier at high temperature, shearing and emulsifying the resulting carotenoid oil solution with the aqueous phase of the wall material, and then isomerizing the resulting emulsion with a Blancospora trispora fermentation enzyme solution followed by spray drying to obtain high all-trans carotenoid microcapsules.

2. The method for preparing high all-trans carotenoid microcapsules according to claim 1, characterized in that, The *Blancium trispora* fermentation enzyme solution was prepared by the following method: positive and negative strains of *Blancium trispora* were inoculated into slant culture medium and cultured until spores grew. The obtained positive and negative spores were inoculated into seed culture medium for seed culture. The obtained positive and negative strain seed solutions were co-inoculated into fermentation medium for fermentation culture, followed by solid-liquid separation. The obtained solid was then crushed, dissolved in buffer solution, and separated into solid and liquid. The resulting filtrate was the *Blancium trispora* fermentation enzyme solution.

3. The method for preparing high all-trans carotenoid microcapsules according to claim 1, characterized in that, The amount of the *Brasilaria trispora* fermentation enzyme solution used is 0.3 to 0.6 times the amount of carotenoids.

4. The method for preparing high all-trans carotenoid microcapsules according to claim 1, characterized in that, The carotenoids are selected from at least one of β-carotene, lycopene, canthaxanthin, astaxanthin, and lutein.

5. The method for preparing high all-trans carotenoid microcapsules according to claim 1, characterized in that, The carrier oil is at least one of animal oil, vegetable oil, and fatty acid ester; preferably, the amount of the carrier oil is 0.8 to 1.7 times the amount of carotenoids; preferably, the emulsifier is selected from at least one of Tween, glycerides, lecithin, and sucrose fatty acid esters; preferably, the amount of the emulsifier is 0.01 to 0.03 times the amount of carotenoids.

6. The method for preparing high all-trans carotenoid microcapsules according to claim 1, characterized in that, The wall material is selected from at least one of modified starch, protein compound wall materials, and carbohydrate wall materials; preferably, the amount of the wall material used is 3 to 9 times the amount of carotenoids.

7. The method for preparing high all-trans carotenoid microcapsules according to any one of claims 1 to 6, characterized in that, The oil phase also contains an antioxidant; preferably, the antioxidant is selected from at least one of butylated hydroxytoluene, tert-butylhydroquinone, butylated hydroxyanisole, α-tocopherol, gallate, para-hydroxybenzoate, ascorbyl palmitate, rosemary extract and tea polyphenols; preferably, the amount of the antioxidant is 0.1 to 0.6 times the amount of carotenoids.

8. The method for preparing high all-trans carotenoid microcapsules according to any one of claims 1 to 6, characterized in that, The conditions for high-temperature melting include a temperature of 150℃ to 190℃ and a time of 3 to 10 seconds; preferably, the conditions for isomerization treatment include a temperature of 25℃ to 30℃ and a time of 1 to 5 hours.

9. The method for preparing high all-trans carotenoid microcapsules according to any one of claims 1 to 6, characterized in that, The method further includes adding a reducing agent before and / or during the isomerization process; preferably, the reducing agent is selected from at least one of sodium sulfite, sodium thiosulfate and sodium dithionite; preferably, the amount of the reducing agent is 0.01 to 0.04 times the mass of the carotenoid.

10. High all-trans carotenoid microcapsules prepared by the method according to any one of claims 1 to 9.