Lutein yeast microcapsule and preparation method thereof

Abstract

The invention relates to the field of food processing, in particular to a lutein yeast microcapsule and a preparation method thereof. According to the preparation method of the lutein yeast microcapsule, the embedding rate of the yeast microcapsule prepared by utilizing the preparation method provided by the invention reaches 87.5% or above, and compared with the prior art, a better effect is achieved. According to the method, freeze drying serves as a non-thermal processing technology, the freeze drying technology can reduce the biological activity loss of encapsulated substances in the processing process, liquid microcapsule particles can be converted into solid microcapsule particles through the freeze drying method, the product characters are changed, transportation and storage are facilitated, and meanwhile the requirements of consumers are met. The freeze-drying technology can greatly retain the nutritional ingredients of the materials, the dried product has the characteristics of low water content, good rehydration property, light weight and the like, the storage period can be prolonged, and the transportation is convenient.

Description

Technical Field

[0001] The invention relates to the field of food processing, and in particular to a lutein yeast microcapsule and a preparation method thereof. Background Art

[0002] Lutein (3,3-dihydroxy-α-carotene) is an oxygen-containing carotenoid and a hydroxylated derivative of terpenoid compounds. It has a particularly good protective effect against age-related macular degeneration (AMD) and cataracts. Lutein also has antioxidant, anti-cancer, coloring, reduces the incidence of cardiovascular disease and protects vision. It is widely found in vegetables, flowers, fruits and certain algae. Lutein has multiple biological activities and a color-enhancing effect. Therefore, it is widely used in the fields of medicine, cosmetics, feed, etc., and research on lutein is increasingly valued at home and abroad.

[0003] Marigold (Tagetes erecta L.) is a herbaceous plant of the genus Tagetes in the Asteraceae family, native to Mexico. It is often cultivated as a garden flower around the world because of its large flower shape, colorful colors and easy cultivation. Since marigold flowers are rich in carotenoids, the lutein contained in marigold accounts for 70%-79% of the carotenoids contained in it, it can be directly used as a raw material for the extraction of lutein.

[0004] At present, lutein is widely used in the food industry as a colorant and nutritional enhancer, but it is easily oxidized and deteriorated by its own internal unsaturated structure and external conditions (light, high temperature, acid and alkali, metal ions, moisture and other factors), and is very unstable. In addition, lutein has poor water solubility, which limits its absorption in the gastrointestinal tract, thereby reducing its oral bioavailability. It can be seen that the instability and poor water solubility of lutein greatly limit its application in food processing. At present, Chinese patent CN106307492A embeds lutein, but its embedding rate is up to 85%. The present invention intends to optimize the preparation method of lutein yeast microcapsules to provide a method with a higher lutein embedding rate to improve the utilization rate of lutein. Summary of the invention

[0005] The purpose of the present invention is to provide a lutein yeast microcapsule and a preparation method thereof to solve the problems existing in the above-mentioned prior art. The present invention provides a preparation method of lutein yeast microcapsule, and the embedding rate of the yeast microcapsule prepared by the preparation method reaches more than 87.5%, thereby improving the utilization rate of lutein.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a method for preparing lutein yeast microcapsules, comprising the following steps:

[0008] After inactivating the yeast at high temperature, pretreated yeast cells are obtained;

[0009] Mixing the pretreated yeast cells with water to obtain a yeast cell dispersion;

[0010] The yeast cell dispersion and the lutein concentrate are mixed, homogenized, water-bath embedded, centrifuged and freeze-dried in sequence to obtain lutein yeast microcapsules.

[0011] Preferably, the mass ratio of the pretreated yeast cells to water is 1:2.

[0012] Preferably, the mass ratio of the yeast cell dispersion to the lutein concentrate is 1:(2-4).

[0013] Preferably, the homogenization speed is 8000 rpm and the time is 20 s.

[0014] Preferably, the water bath embedding time is 1-2 hours and the temperature is 35-45°C.

[0015] Preferably, the centrifugal speed is 4000 rpm, the time is 5 min, and the number of times is 2-3 times.

[0016] Preferably, the freeze-drying temperature is -22°C and the time is 8 hours.

[0017] Preferably, the high temperature inactivation temperature is 125°C and the time is 15 minutes.

[0018] Preferably, the method for preparing the lutein concentrate comprises the steps of mixing marigold dried flower powder and a solvent in a mass volume ratio of 1 g:40 mL, and then extracting and concentrating in sequence to obtain the lutein concentrate.

[0019] The present invention provides a lutein yeast microcapsule prepared by the above-mentioned preparation method.

[0020] The present invention discloses the following technical effects:

[0021] The present invention provides a method for preparing lutein yeast microcapsules. The embedding rate of the yeast microcapsules prepared by the preparation method provided by the present invention reaches more than 87.5%, which achieves better results than the prior art. In the present invention, freeze drying is a non-thermal processing technology. The freeze drying technology can reduce the loss of biological activity of the encapsulated material during the processing process. The present invention can transform the liquid into solid microcapsule particles by freeze drying, change the product properties, facilitate transportation and storage, and meet the needs of consumers. Freeze drying technology can retain the nutritional components of the material to a large extent. The dried product has the characteristics of low water content, good rehydration and light weight, which can extend the storage period and facilitate transportation.

[0022] The lutein yeast microcapsules prepared by the present invention use lutein as the core material and yeast cells as the wall material. The core material enters the yeast cells through osmosis to form microcapsules. Traditional wall materials for encapsulating lutein are mostly modified starch, gum arabic, gelatin, α-cyclodextrin, sodium octenyl succinate starch and other materials, but the microcapsules formed by these encapsulation materials have large surface pores and cannot completely prevent acid from entering. Under low pH conditions, the stability of the microcapsules deteriorates and cannot resist the damage of gastrointestinal fluid, thereby reducing the effect and bioavailability of lutein. Yeast microcapsules are a type of microencapsulation immobilization technology that uses yeast cells as encapsulation wall materials. Yeast cells can be encapsulated through their own adsorption properties, and have the advantages of no chemical reagent pollution, good biocompatibility, easy biodegradation, and easy acquisition. Relying on the adsorption properties of yeast cells themselves to complete the encapsulation has many advantages such as no chemical reagent pollution, good biocompatibility, easy biodegradation, easy acquisition, and uniform size of microcapsule products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a schematic diagram of the process flow of lutein yeast microencapsulation;

[0025] Figure 2 This is a scanning electron microscope image of lutein microcapsules;

[0026] Figure 3 This is a graph showing the particle size changes of yeast lutein microcapsules in the stomach;

[0027] Figure 4 This is a graph showing the particle size changes of yeast lutein microcapsules in the intestine;

[0028] Figure 5 This is a diagram showing the fluorescence signal excitation of yeast lutein microcapsules in the stomach;

[0029] Figure 6 This is the fluorescence signal excitation of yeast lutein microcapsules in the intestine. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0032] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0033] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0034] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0035] Example 1

[0036] The preparation process of lutein yeast microcapsules is as follows Figure 1 As shown, specifically:

[0037] a) Take marigold dried flowers and grind them with a traditional Chinese medicine grinder, pass through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add anhydrous ethanol to the extraction sealed vacuum bag at a ratio of 1:40 (1g:40mL), mix well and put into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0038] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0039] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:3 (g:g), homogenize at 8000rpm for 20s, bathe in a 35℃ water bath, shake every 10min, embed for 2h, wash with anhydrous ethanol 2-3 times, centrifuge at 4000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein yeast microcapsule powder with orange-yellow surface.

[0040] Then the embedding rate of yeast microcapsules was calculated: the embedding rate was calculated using the concentration difference before and after yeast cell embedding: W%=1-(w1 / w2)*100%; where: W(%) is the embedding rate, W1: the mass concentration of unencapsulated lutein (mg / mL), W2: the total mass concentration of lutein in the microcapsules (mg / mL), and the embedding rate was 87.6%.

[0041] Example 2

[0042] The preparation process of lutein yeast microcapsules is as follows Figure 1 As shown, specifically:

[0043] a) Take marigold dried flowers and grind them with a traditional Chinese medicine grinder, pass through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add 40mL of anhydrous ethanol to the extraction sealed vacuum bag at a solid-liquid ratio of 1:40, mix well and put into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0044] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0045] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:2 (g:g), homogenize at 8000rpm for 20s, bathe in a 45℃ water bath, shake every 10min, embed for 1.5h, wash with anhydrous ethanol 2-3 times, centrifuge at 4000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein microcapsule powder with an orange-yellow surface and an embedding rate of 88.5%.

[0046] Example 3

[0047] The preparation process of lutein yeast microcapsules is as follows Figure 1 As shown, specifically:

[0048] a) Take marigold dried flowers and grind them with a Chinese medicine grinder, pass through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add 40mL of anhydrous ethanol to the extraction sealed vacuum bag at a ratio of 1:40, mix well and put into the extraction container. The extraction pressure is 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate.

[0049] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0050] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:3 (g:g), homogenize at 8000rpm for 20s, bathe in a 45℃ water bath, shake every 10min, embed for 1h, wash with anhydrous ethanol 2-3 times, centrifuge at 4000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein microcapsule powder with an orange-yellow surface and an embedding efficiency of 90.1%.

[0051] Example 4

[0052] The preparation process of lutein yeast microcapsules is as follows Figure 1 As shown, specifically:

[0053] a) Take marigold dried flowers and grind them with a traditional Chinese medicine grinder, pass through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add 40mL of anhydrous ethanol to the extraction sealed vacuum bag at a solid-liquid ratio of 1:40, mix well and put into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0054] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0055] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:3 (g:g), homogenize at 8000rpm for 20s, bathe in a 40℃ water bath, shake every 10min, embed for 1.5h, wash with anhydrous ethanol 2-3 times, centrifuge at 4000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein microcapsule powder with an orange-yellow surface and an embedding efficiency of 95.3%.

[0056] Example 5

[0057] The preparation process of lutein yeast microcapsules is as follows Figure 1 As shown, specifically:

[0058] a) Take marigold dried flowers and grind them with a traditional Chinese medicine grinder, pass through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add 40mL of anhydrous ethanol to the extraction sealed vacuum bag at a solid-liquid ratio of 1:40, mix well and put into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0059] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0060] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form an aqueous dispersion with a concentration of 10 6 / mL, added to the yeast cell dispersion at a material-core ratio of 1:4 (g:g), homogenized at 8000rpm for 20s, water-bathed in a 40℃ water bath, shaken every 10min, embedded for 1h, washed with anhydrous ethanol 2-3 times, centrifuged at 4000rpm for 5min, centrifuged 2-3 times, freeze-dried at -22℃ for 8h, and obtained lutein microcapsule powder with an orange-yellow surface and an embedding efficiency of 96.2%.

[0061] Example 6

[0062] The preparation process of lutein yeast microcapsules is as follows Figure 1 As shown, specifically:

[0063] a) Take marigold dried flowers and grind them with a Chinese medicine grinder, pass them through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add anhydrous ethanol to the extraction sealed vacuum bag at a solid-liquid ratio of 1:40, mix well and put them into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0064] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0065] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:2 (g:g), homogenize at 4000rpm for 20s, bathe in a 35℃ water bath, shake every 10min, embed for 1.5h, wash with anhydrous ethanol 2-3 times, centrifuge at 5000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein microcapsule powder with an orange-yellow surface and an embedding efficiency of 93.07%.

[0066] Comparative Example 1

[0067] The preparation of lutein yeast microcapsules is as follows:

[0068] a) Take marigold dried flowers and grind them with a Chinese medicine grinder, pass them through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add anhydrous ethanol to the extraction sealed vacuum bag at a solid-liquid ratio of 1:40, mix well and put them into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0069] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0070] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:1 (g:g), homogenize at 4000rpm for 20s, bathe in a 45℃ water bath, shake every 10min, embed for 1.5h, wash with anhydrous ethanol 2-3 times, centrifuge at 5000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein microcapsule powder with an orange-yellow surface and an embedding efficiency of 39.07%.

[0071] Comparative Example 2

[0072] The preparation of lutein yeast microcapsules is as follows:

[0073] a) Take marigold dried flowers and grind them with a Chinese medicine grinder, pass them through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add anhydrous ethanol to the extraction sealed vacuum bag at a solid-liquid ratio of 1:40, mix well and put them into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0074] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0075] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:1 (g:g), homogenize at 4000rpm for 20s, bathe in a 40℃ water bath, shake every 10min, embed for 2h, wash with anhydrous ethanol 2-3 times, centrifuge at 5000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein microcapsule powder with an orange-yellow surface and an embedding efficiency of 49.67%.

[0076] Comparative Example 3

[0077] The preparation of lutein yeast microcapsules is as follows:

[0078] a) Take marigold dried flowers and grind them with a Chinese medicine grinder, pass them through a 60-mesh sieve to obtain marigold dried flower powder. Weigh 1g of marigold dried flower powder, add anhydrous ethanol to the extraction sealed vacuum bag at a solid-liquid ratio of 1:40, mix well and put them into the extraction container. At an extraction pressure of 100MPa, the pressure holding time is 3min, and the cycle is repeated 3 times, and finally evaporated and concentrated on a rotary evaporator to obtain lutein concentrate;

[0079] b) taking a certain amount of Angel dry yeast, placing it in a weighing bottle, and placing it in an open electric heating blast drying oven set at 125° C. for high temperature inactivation for 15 minutes to complete the pretreatment of yeast cells and obtain pretreated yeast cells;

[0080] c) taking the pretreated yeast cells obtained in step b), adding twice the amount of distilled water to form a yeast cell dispersion with a concentration of 10 6 / mL, add lutein concentrate to yeast cell dispersion at a material-core ratio of 1:1 (g:g), homogenize at 4000rpm for 20s, bathe in a 40℃ water bath, shake every 10min, embed for 1h, wash with anhydrous ethanol 2-3 times, centrifuge at 5000rpm for 5min, centrifuge 2-3 times, freeze-dry at -22℃ for 8h to obtain lutein microcapsule powder with an orange-yellow surface and an embedding efficiency of 43.18%.

[0081] Experimental example

[0082] The embedding effect of the yeast lutein microcapsules prepared in Example 5 was observed under a scanning electron microscope. Figure 2 As shown, the specific implementation is:

[0083] The morphology of lutein microcapsules was observed. A trace amount of lutein microcapsule freeze-dried powder was dissolved in 3 mL of anhydrous ethanol and microwaved for 10 minutes to obtain a lutein microcapsule suspension. The suspension was taken with a capillary glass tube and dropped onto a sample table with conductive tape. The sample was gold-plated and the appropriate field of view was selected to photograph and observe the lutein microcapsules. The results showed that the yeast lutein microcapsules were plump and smooth, and yeast as an embedding wall material had a good effect on lutein embedding.

[0084] Example 5 Study on the tolerance of yeast lutein microcapsules in simulated in vitro digestion in the gastrointestinal tract

[0085] Particle size changes of yeast lutein microcapsules in the stomach Figure 3 As shown, the specific implementation is:

[0086] Take 3g of lutein microcapsules for in vitro simulation experiments. Add 5mL of simulated gastric juice preheated to 37℃ to 400mL of 0.9% saline, mix well, accurately adjust pH to 2.0 with 1mol / LHCl solution, set the constant temperature shaker parameters to 37℃, 100r / s speed, wait until the in vitro simulated gastric environment temperature reaches 37℃, weigh 3g of lutein microcapsule sample and add it to start timing, the reaction time is 4h, sample once every 0.5h, 5mL each time, and quickly place the sample in a 70℃ water bath to inactivate for 5min, then put it in the refrigerator to cool, centrifuge at 10000r / min for 5min, take the supernatant to measure the microcapsule particle size, observe the digestion of the microcapsule in gastric juice, and repeat the experiment more than 3 times. The results show that between 1-4h, the size of the microcapsule particle size in gastric juice does not change much overall, and the particle size is the largest at 2h, proving that during the digestion process in the stomach stage, the release rate is low and the microcapsules are well tolerated in gastric juice.

[0087] Example 5 The particle size of the yeast lutein microcapsules prepared in the intestine changes as follows Figure 4 As shown, the specific implementation is:

[0088] After the in vitro simulated gastric digestion was completed, 50 mL of intestinal fluid preheated to 37 ° C was added, mixed evenly, and the pH was adjusted to 7.0 with 1 mol / L sodium bicarbonate solution. The constant temperature shaker parameters were set to 37 ° C, 120 r / s, and the reaction was carried out for 4 hours. Samples were taken once at 0.5 h, 1 h, 2 h, 3 h, and 4 h, and 5 mL was sampled each time. The samples were quickly placed in a 70 ° C water bath for inactivation for 5 minutes, and then placed in a refrigerator for cooling. After centrifugation at 10000 r / min for 5 minutes, the supernatant was taken to determine the particle size of the microcapsules, and the digestion of the microcapsules in the intestinal fluid was observed. The experiment was repeated more than 3 times. The results showed that the particle size of the microcapsules in the intestinal fluid first gradually increased and then rapidly decreased, proving that the microcapsules were effectively released in the intestinal fluid, resulting in a decrease in particle size.

[0089] The fluorescence signal excitation of the yeast lutein microcapsules prepared in Example 5 in the stomach is as follows Figure 5 As shown, the specific implementation is:

[0090] Take 3g of lutein microcapsules for in vitro simulation experiments. Add 5mL of simulated gastric juice preheated to 37℃ to 400mL of 0.9% saline, mix well, accurately adjust the pH to 2.0 with 1mol / LHCl solution, set the constant temperature shaker parameters to 37℃, 100r / s speed, wait until the in vitro simulated gastric environment temperature reaches 37℃, weigh 3g of lutein microcapsule sample and add it to start timing, react for 2h, take 5mL of sample, and quickly place the sample in a 70℃ water bath to inactivate for 5min, then put it in the refrigerator to cool, centrifuge at 10000r / min for 5min, take the supernatant to measure the microcapsule fluorescence excitation signal, observe the digestion of the microcapsule in gastric juice, and repeat the experiment more than 3 times. The results show that the yeast lutein microcapsules show green fluorescence under a fluorescence microscope, the fluorescence distribution is uniform, the signal image is clear, and there is no extra noise, which proves that the lutein content in gastric juice after 2h of reaction is high and has a large release rate.

[0091] The fluorescence signal excitation of yeast lutein microcapsules in the intestine is as follows Figure 6 As shown, the specific implementation is:

[0092] After the in vitro simulated gastric digestion was completed, 50 mL of intestinal fluid preheated to 37 ° C was added, mixed evenly, and the pH was adjusted to 7.0 with 1 mol / L sodium bicarbonate solution. The constant temperature shaker parameters were set to 37 ° C, 120 r / s, and the reaction was carried out for 4 hours. After 4 hours of reaction, 5 mL of the sample was taken. The sample was quickly placed in a 70 ° C water bath for inactivation for 5 minutes, and then placed in a refrigerator for cooling. After centrifugation at 10000 r / min for 5 minutes, the supernatant was taken to measure the microcapsule fluorescence excitation signal, and the digestion of the microcapsules in the intestinal fluid was observed. The experiment was repeated more than 3 times. The results showed that the fluorescence signal after 4 hours of reaction in the intestinal fluid was weakened, blurred, and agglomerated. It can be seen that the yeast lutein microcapsules were well digested and utilized after 4 hours.

[0093] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing lutein yeast microcapsules, characterized in that: The following steps are involved: After inactivating the yeast at high temperature, pretreated yeast cells are obtained; Mixing the pretreated yeast cells with water to obtain a yeast cell dispersion; The yeast cell dispersion and the lutein concentrate are mixed, homogenized, water-bath embedded, centrifuged and freeze-dried in sequence to obtain lutein yeast microcapsules.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the pretreated yeast cells to water is 1:

2.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the yeast cell dispersion to the lutein concentrate is 1:(2-4).

4. The preparation method according to claim 1, characterized in that: The homogenization speed is 8000 rpm and the time is 20 s.

5. The preparation method according to claim 1, characterized in that: The water bath embedding time is 1-2 hours, and the temperature is 35-45°C.

6. The preparation method according to claim 1, characterized in that: The centrifugal speed is 4000 rpm, the time is 5 min, and the number of times is 2-3 times.

7. The preparation method according to claim 1, characterized in that: The freeze-drying temperature is -22°C and the time is 8 hours.

8. The preparation method according to claim 1, characterized in that: The temperature of the high temperature inactivation is 125° C. and the time is 15 min.

9. The preparation method according to claim 1, characterized in that: The preparation method of the lutein concentrate comprises the steps of mixing marigold dried flower powder and a solvent in a mass volume ratio of 1 g:40 mL, and then extracting and concentrating in sequence to obtain the lutein concentrate.

10. Lutein yeast microcapsules prepared by the preparation method according to any one of claims 1 to 9.

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