Method for preparing low-crystalline-state beta-carotene and application thereof

Abstract

The invention provides a method for preparing low-crystalline-state beta-carotene and application of the low-crystalline-state beta-carotene, and the method comprises the following steps: carrying out hot-melting extrusion treatment on a beta-carotene crystal raw material to obtain a beta-carotene hot-melting extruded material; and carrying out crushing treatment on the beta-carotene hot-melt extruded material, so as to obtain the low-crystalline-state beta-carotene. The prepared low-crystalline-state beta-carotene is low in relative crystallinity and high in cis-isomer proportion, and the beta-carotene microcapsule developed by using the low-crystalline-state beta-carotene is in an amorphous state, is high in water solubility and bioaccessibility and has a relatively good industrial application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of food, and in particular to a method for preparing low-crystalline beta-carotene and application thereof. Background Art

[0002] β-carotene has high nutritional, health and medical application value, and has been widely used in industries such as food, medical, feed and cosmetics. However, due to its poor solubility in water, low oral bioavailability, poor physical and chemical stability and other defects, its efficient use is greatly limited. Microcapsule embedding technology is an effective way to solve the above problems. The use of amphiphilic biopolymers to emulsify and embed β-carotene can not only greatly improve the water dispersibility of β-carotene, but also significantly enhance its physical and chemical stability. However, the principles of microcapsule embedding technology are different and there are many methods. Therefore, it is particularly important to find a β-carotene microcapsule embedding method suitable for application in the food field. Patent documents such as CN 115119904A and CN 111904944A disclose that the β-carotene microcapsules prepared by single wet grinding have high loading. However, the β-carotene in the microcapsules prepared by the single wet grinding process still exists in a crystalline form, the solubility of β-carotene is low, and its biological accessibility is reduced at the same time.

[0003] Most of the natural β-carotene in food raw materials exists in the all-trans configuration, while more than 50% of the β-carotene in human blood and tissues is the cis isomer. Studies have shown that the cis isomer of β-carotene has a high absorption rate, is not easy to crystallize, has a low aggregation tendency, has a high solubility in mixed micelles, and is conducive to being preferentially absorbed by small intestinal epithelial cells. Therefore, compared with the all-trans configuration, the cis isomer of β-carotene has higher bioaccessibility.

[0004] At present, there is an urgent need to improve the crystal state and cis-isomer ratio of β-carotene raw materials, and to improve the solubility and bioaccessibility of β-carotene microcapsule products. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art to a certain extent. To this end, the present invention provides a method for preparing low-crystalline β-carotene and its application. The low-crystalline β-carotene prepared by the method of the present invention has low relative crystallinity and a high proportion of cis-isomers. The β-carotene microcapsules developed by the method have high solubility and high bioaccessibility.

[0006] In the first aspect of the present invention, the present invention proposes a method for preparing low-crystalline β-carotene. According to an embodiment of the present invention, the method comprises: subjecting a β-carotene crystal raw material to hot-melt extrusion to obtain a β-carotene hot-melt extrudate; and subjecting the β-carotene hot-melt extrudate to pulverization to obtain the low-crystalline β-carotene. The low-crystalline β-carotene prepared by the method of the embodiment of the present invention has low relative crystallinity and a high ratio of cis-isomers, and the β-carotene microcapsules developed by the method have high solubility and high bioaccessibility.

[0007] According to an embodiment of the present invention, the mixture of the β-carotene crystal raw material and the eutectic auxiliary material is subjected to the hot melt extrusion process, thereby further reducing the relative crystallinity of the β-carotene and increasing the proportion of the cis isomer.

[0008] According to an embodiment of the present invention, the eutectic auxiliary material is selected from at least one of an emulsifier, a polysaccharide, and an antioxidant.

[0009] According to an embodiment of the present invention, the emulsifier is selected from at least one of polyglycerol fatty acid esters, monoester sucrose fatty acid esters, and stearic acid glyceryl ester, thereby further reducing the relative crystallinity of β-carotene.

[0010] According to an embodiment of the present invention, the emulsifier is selected from at least one of twelve polyglycerol fatty acid esters, ten polyglycerol fatty acid esters, eight polyglycerol fatty acid esters, six polyglycerol fatty acid esters, three polyglycerol fatty acid esters, sucrose fatty acid monoesters, sucrose fatty acid diesters, sucrose fatty acid triesters, sucrose fatty acid polyesters, glyceryl monostearate, distearate, tristearate, acetylated mono- and diglyceryl fatty acid esters, calcium stearate, sodium stearoyl lactylate, spans, and tweens. The inventor has determined the above-mentioned preferred emulsifier through a large number of experimental screenings. Thus, the relative crystallinity of beta-carotene is further reduced.

[0011] According to an embodiment of the present invention, the polysaccharide is selected from at least one of polydextrose, trehalose, sucrose, maltose, hydroxypropyl methylcellulose, carboxymethyl cellulose, ethyl cellulose, tuckahoe polysaccharide, amino polysaccharide, chitin, agar, hyaluronic acid, and inulin, thereby further reducing the relative crystallinity of β-carotene.

[0012] According to an embodiment of the present invention, the antioxidant is selected from at least one of curcumin, epigallocatechin gallate, resveratrol, α-tocopherol, ascorbyl palmitate, tea polyphenol palmitate, D-ascorbic acid and its sodium salt, tea polyphenols, theaflavins, phospholipids, and rosemary extract. Thus, the retention rate of β-carotene is further improved, and the proportion of cis isomers is increased.

[0013] According to an embodiment of the present invention, the eutectic auxiliary material comprises at least one of: 12 polyglycerol fatty acid esters, 10 polyglycerol fatty acid esters, 8 polyglycerol fatty acid esters, 6 polyglycerol fatty acid esters, polydextrose, trehalose, curcumin, epigallocatechin gallate, α-tocopherol, and ascorbyl palmitate. The inventors have determined the above-mentioned preferred eutectic auxiliary materials through a large number of experimental screenings, thereby further reducing the relative crystallinity of β-carotene and increasing the proportion of cis isomers.

[0014] In some specific embodiments, the eutectic excipient comprises: dodecaned glycerol fatty acid ester and / or α-tocopherol and / or ascorbyl palmitate.

[0015] In some specific embodiments, the mass ratio of the β-carotene crystal raw material to the eutectic auxiliary material is (5-20): 1, preferably (5-10): 1, and more preferably (6-9): 1. Thus, the relative crystallinity of β-carotene is further reduced, and the retention rate of β-carotene is increased.

[0016] According to an embodiment of the present invention, when the eutectic auxiliary material includes α-tocopherol, the α-tocopherol is dissolved in an organic solvent to obtain an α-tocopherol solution, and the α-tocopherol solution is subjected to surface contact treatment with the β-carotene crystals to obtain the mixture. Thus, the β-carotene crystal raw material is prevented from agglomerating before hot melt extrusion.

[0017] According to an embodiment of the present invention, the organic solvent is anhydrous ethanol, and the mass ratio of α-tocopherol to anhydrous ethanol is 1:(2-4). Thus, agglomeration of the β-carotene crystal raw material before hot melt extrusion is further avoided.

[0018] In some specific embodiments, the surface contact treatment comprises: spraying the α-tocopherol solution onto the surface of the β-carotene crystals.

[0019] According to an embodiment of the present invention, the inlet temperature of the material in the hot melt extrusion process is 150-200° C., and the outlet temperature is 80-120° C. The inventors have determined the optimal hot melt extrusion process conditions through a large number of experiments, thereby further reducing the relative crystallinity of β-carotene.

[0020] Furthermore, the inlet temperature of the material in the hot melt extrusion treatment is 180-195° C., and the outlet temperature is 95-100° C. The inventors have determined the optimal hot melt extrusion treatment conditions through a large number of experiments, thereby further reducing the relative crystallinity of β-carotene.

[0021] According to an embodiment of the present invention, before the pulverization process, the β-carotene hot melt extrudate is cooled and solidified, thereby facilitating the pulverization process of the β-carotene hot melt extrudate.

[0022] According to an embodiment of the present invention, the cooling and solidification treatment includes: contacting the β-carotene hot melt extrudate with liquid nitrogen, thereby facilitating rapid cooling and solidification of the β-carotene hot melt extrudate.

[0023] According to an embodiment of the present invention, the pulverized product obtained after the pulverization process is passed through a 60-200 mesh sieve to obtain the low-crystalline β-carotene, preferably 80-100 mesh, thereby obtaining a β-carotene raw material powder with a particle size that meets the requirements.

[0024] In a second aspect of the present invention, the present invention provides a low-crystalline β-carotene. According to an embodiment of the present invention, the low-crystalline β-carotene is prepared according to the above method. The low-crystalline β-carotene according to the present invention has low relative crystallinity and a high proportion of cis-isomers.

[0025] Those skilled in the art will appreciate that the features and advantages described above for the method for preparing low-crystalline β-carotene are also applicable to the low-crystalline β-carotene, and will not be described in detail herein.

[0026] According to an embodiment of the present invention, in the low-crystalline β-carotene, the relative crystallinity of the β-carotene is less than 35%.

[0027] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 30%.

[0028] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 29%.

[0029] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 28%.

[0030] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 27%.

[0031] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 26%.

[0032] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 25%.

[0033] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 22%.

[0034] According to an embodiment of the present invention, the relative crystallinity of the β-carotene is less than or equal to 20%.

[0035] For example, in the low-crystalline β-carotene according to an embodiment of the present invention, the relative crystallinity of β-carotene is 34%, 33%, 32%, 31%, 30%, 29%, 24%, 23%, 21%,

[0036] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 40%.

[0037] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 46%.

[0038] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 50%.

[0039] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 55%.

[0040] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 60%.

[0041] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 63%.

[0042] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 64%.

[0043] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 65%.

[0044] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 66%.

[0045] According to an embodiment of the present invention, the ratio of the cis isomer of the β-carotene is greater than or equal to 67%.

[0046] Illustratively, in the low crystalline β-carotene according to an embodiment of the present invention, the ratio of the cis isomer of β-carotene is 69%, 68%, 62%, 61%, 59%, 58%, 57%, 56%, 54%, 53%, 52%, 51%, 49%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, and 41%.

[0047] In a third aspect of the present invention, the present invention provides a β-carotene dispersion. According to an embodiment of the present invention, the dispersion comprises: the aforementioned low-crystalline β-carotene, an emulsifier, and an antioxidant.

[0048] Those skilled in the art will appreciate that the features and advantages described above for the method for preparing low-crystalline β-carotene are also applicable to the β-carotene dispersion, and will not be described in detail herein.

[0049] According to an embodiment of the present invention, the emulsifier is selected from at least one of sodium starch octenyl succinate, sodium carboxymethyl cellulose, sodium caseinate, soybean polysaccharide, gum arabic, maltodextrin, whey protein isolate, soybean protein isolate, tea saponin and Tween. Thus, the stability, bioavailability, particle size distribution and other properties of the dispersion are further improved.

[0050] According to an embodiment of the present invention, the antioxidant is selected from at least one of BHA, BHT, ethoxyquin, TBHQ, tea polyphenols, α-tocopherol, ascorbic acid, sodium L-ascorbate, ascorbyl palmitate, sodium D-isoascorbate, and rosemary extract. Thus, the oxidative degradation of β-carotene during the preparation process and storage process is further alleviated.

[0051] According to an embodiment of the present invention, the content of the antioxidant is 10-30% based on the mass of the low-crystalline β-carotene.

[0052] According to an embodiment of the present invention, the mass ratio of the low-crystalline β-carotene, emulsifier, and antioxidant is (3-7): (10-20): (0.8-1.2), preferably 5: (12-16): 1, and more preferably 5: 14: 1. Thus, a β-carotene dispersion with good biological properties is obtained.

[0053] According to an embodiment of the present invention, the emulsifier is sodium starch octenyl succinate, thereby further improving the emulsification performance of the dispersion.

[0054] According to an embodiment of the present invention, the antioxidant comprises: ascorbyl palmitate, tea polyphenols and sodium L-ascorbate, thereby further improving the antioxidant performance of the dispersion.

[0055] According to an embodiment of the present invention, the mass ratio of ascorbyl palmitate, tea polyphenols and sodium L-ascorbate is 1:1:2. The inventors have determined this optimal mass ratio through a large number of experiments.

[0056] According to an embodiment of the present invention, the dispersion is an emulsion or a suspension. The emulsion or the suspension can be used to further prepare a β-carotene product.

[0057] In a fourth aspect of the present invention, the present invention provides a β-carotene product. According to an embodiment of the present invention, the product comprises: the aforementioned low-crystalline β-carotene or the aforementioned β-carotene dispersion.

[0058] According to an embodiment of the present invention, the β-carotene product is a β-carotene microcapsule. Thus, the bioavailability and product stability of β-carotene are further improved. The β-carotene microcapsule according to an embodiment of the present invention has high solubility, high bioaccessibility and good product stability.

[0059] In a fifth aspect of the present invention, the present invention provides a method for preparing β-carotene microcapsules. According to an embodiment of the present invention, the method comprises: preparing low-crystalline β-carotene according to the above method.

[0060] Those skilled in the art will appreciate that the features and advantages described above for the method for preparing low-crystalline β-carotene are also applicable to the method for preparing β-carotene microcapsules, and will not be described in detail herein.

[0061] According to an embodiment of the present invention, the method further comprises: dispersing the low-crystalline β-carotene with the aforementioned emulsifier and antioxidant to obtain a β-carotene dispersion; and spray-drying the β-carotene dispersion to obtain the β-carotene microcapsules.

[0062] According to an embodiment of the present invention, before the spray drying process, the β-carotene dispersion is wet-ground to obtain a nano-scale β-carotene dispersion, thereby further increasing the loading capacity of the β-carotene microcapsules.

[0063] In some specific embodiments, the wet grinding speed is 1500-3500 rpm, the time is 1-5 hours, and the temperature is 18-28°C; the speed is preferably 1800-2700 rpm, the time is preferably 1.5-2 hours, and the temperature is preferably 22-28°C. The inventors have determined the optimal wet grinding conditions through a large number of experiments. Thus, the loading capacity and bioaccessibility of β-carotene microcapsules are further improved.

[0064] In some specific embodiments, the air inlet temperature of the spray drying process is 105-165°C, the air outlet temperature is 60-80°C, and the feed rate is 100-500mL / h; the air inlet temperature is preferably 105-145°C, the air outlet temperature is preferably 70-80°C, and the feed rate is preferably 300-400mL / h. The inventors have determined this spray drying condition after a large number of experiments. Thus, the bioaccessibility and solubility of the β-carotene microcapsules are further improved.

[0065] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0067] Figure 1 The X-ray diffraction patterns of the β-carotene crystal raw material of Example 1 of the present invention and the β-carotene after hot-melt extrusion of the β-carotene crystal raw material (control group);

[0068] Figure 2 Schematic diagram of the preparation method of amorphous β-carotene microcapsules of Examples 3 to 6 of the present invention;

[0069] Figure 3 The X-ray diffraction patterns of the β-carotene microcapsules of Example 3 and Comparative Example 1 of the present invention;

[0070] Figure 4 This is a graph showing the results of investigating the solubility and bioaccessibility of β-carotene in β-carotene microcapsules of Examples 3 to 6 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0071] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0072] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0073] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0074] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0075] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0076] As used herein, the term "low-crystalline β-carotene" refers to a special form of β-carotene having a lower crystallinity.

[0077] In the embodiment of the present invention, the relative crystallinity of β-carotene is determined as follows: The relative crystallinity of β-carotene in β-carotene microcapsules is determined by using an X-ray diffractometer (D8, Bruker, Germany). The sample is evenly spread in a sample pool for detection. During the measurement, the X-ray scanning range is 10° to 50° (2θ), the step size is 0.02°, and the step time is 5s. The X-ray diffraction pattern is analyzed using MDI Jade 6 software, and the relative crystallinity of β-carotene is calculated.

[0078] The calculation formula is as follows:

[0079] β-carotene relative crystallinity (%) = (sum of crystalline regions / sum of crystalline regions and amorphous regions) × 100% In the present embodiment, the retention rate of hot-melt extruded β-carotene and the ratio of cis-trans isomers are measured as follows: a high performance liquid chromatograph (Agilent-1100, Agilent Technologies, USA) equipped with a DAD detector is used to quantitatively measure the retention rate of hot-melt extruded β-carotene and the ratio of cis-trans isomers. Accurately weigh 10 mg of β-carotene hot-melt extrudate, dissolve it in 20 mL of chromatographic grade dichloromethane, accurately draw 0.5 mL of the dissolved solution, dilute it to 9 mL with chromatographic grade dichloromethane, and filter the diluted dissolved solution with an organic filter membrane with a pore size of 0.45 μm to remove impurities for sample injection. The HPLC measurement parameters are as follows: the chromatographic column is C 30 (250×4.6mm, YMC Co., Ltd., Japan), the column temperature was 25°C, the wavelength was 450nm, the mobile phase A was a mixture of methanol, acetonitrile and purified water (73.5:24.5:2, v / v), the mobile phase B was dimethyl tert-butyl ether, and the mobile phase flow rate was 1mL / min.

[0080] In the present embodiment, the loading rate and embedding rate of β-carotene in the microcapsule are determined as follows: First, the β-carotene in the rehydrated dispersion is extracted multiple times using a mixed reagent of anhydrous ethanol and n-hexane (1:3, v / v) until the dispersion is colorless. The absorbance of the β-carotene extract is measured at a wavelength of 450nm using an ultraviolet-visible spectrophotometer (UV-1800, Shimadzu Corporation, Japan). The β-carotene standard curve (y=0.2623x+0.0247, R 2 =0.9996) to quantitatively calculate the β-carotene content in the extract. The formula for calculating the encapsulation efficiency and loading rate of β-carotene microcapsules is as follows:

[0081] β-carotene embedding rate (%) = embedded β-carotene mass (mg) / total β-carotene mass (mg) × 100%

[0082] β-carotene loading rate (%) = mass of embedded β-carotene (mg) / total mass of β-carotene microcapsules (mg) × 100%

[0083] In the present embodiment, the particle size of the rehydrated dispersion of β-carotene microcapsules was measured as follows: the particle size of the β-carotene nanodispersion and the rehydrated dispersion was measured using a Zeta-sizer particle size analyzer (ZS90, Malvern, UK) based on the principle of dynamic light scattering. Before the measurement, the β-carotene nanodispersion and the rehydrated dispersion (0.1 g / 100 g, w / v) were diluted 100 times with deionized water to avoid multiple light scattering effects.

[0084] In the present embodiment, the solubility of β-carotene in the microcapsule is determined as follows: 0.1 g of β-carotene microcapsule powder is accurately weighed and added to 100 mL of deionized water (pH 7), and stirred thoroughly. 10 mL of the sample is measured and centrifuged at 15000 rpm for 60 min at 10° C. The supernatant is filtered using a 0.45 μm nylon filter to further remove undissolved particles, and the mass of dissolved β-carotene is calculated according to the above-mentioned UV-visible spectrophotometry. The solubility calculation formula of β-carotene microcapsule is as follows:

[0085] β-carotene solubility (%) = dissolved β-carotene mass (mg) / total β-carotene mass (mg) × 100%

[0086] In the examples of the present invention, the bioaccessibility of β-carotene in the microcapsules was determined as follows: a static three-stage (i.e., oral cavity, stomach and small intestine stages) simulated digestion model was used to determine the bioaccessibility of β-carotene in the microcapsules.

[0087] Simulated oral phase: 10 mL of 0.2 g / 100 mL (w / v) rehydrated β-carotene microcapsules were injected into 10 mL of simulated salivary fluid (SSF, including 0.75 mg / mL α-amylase and 0.17 mg / mL CaCl2) in a 100 mL glass conical bottle. The mixture was then adjusted to pH 6.8 and continuously shaken at a constant speed of 150 rpm for 2 min.

[0088] Simulated gastric phase: The mixed solution (20 mL) obtained after the oral phase was injected into a glass conical bottle containing 20 mL of simulated gastric fluid (SGF, including 3.2 mg / mL pepsin and 2.0 mg / mL NaCl). Subsequently, the resulting mixture was adjusted to pH 3 with a pre-prepared hydrochloric acid solution (1.0 M). The mixed digestion solution was shaken at a constant rate of 150 rpm for 2 h in a 37°C water bath. After the gastric phase digestion, the resulting mixed solution was adjusted to pH 7.0 by a pre-prepared sodium hydroxide solution (1.0 M) to inactivate the digestive enzymes.

[0089] Simulated small intestinal phase: The mixed digestive fluid (20 mL) obtained after the gastric phase was injected into 20 mL of simulated intestinal fluid (SIF, containing 12.0 mg / mL bile salts, 2.0 mg / mL pancreatin, 6.8 mg / mL KH2PO4, 8.8 mg / mL NaCl). The obtained digestive fluid was adjusted to pH 7.0 and then shaken at a constant speed of 150 rpm for 2 h in a 37°C water bath.

[0090] After the digestion of the small intestine phase is completed, the bioaccessibility of β-carotene in the microcapsules can be determined. The small intestine digestion fluid is transferred to a 50 mL centrifuge tube and centrifuged at 18000 rpm and 10°C for 60 min. The supernatant obtained by centrifugation is defined as the mixed micelle phase. The bioaccessibility of β-carotene in the microcapsules is determined by the following formula:

[0091] β-carotene bioaccessibility (%) = (β-carotene concentration in mixed micelle phase / initial β-carotene concentration in microcapsule rehydrated dispersion) × 100%

[0092] In the examples of the present invention, β-carotene crystals (purity>98%) were purchased from Zhejiang Xinhecheng Co., Ltd., sodium starch octenylsuccinate (OSA modified starch, Hi-Cap100) was purchased from Ingredion (China) Ingredients Co., Ltd., and other reagents were all commercially available chemically pure reagents.

[0093] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0094] Example 1: Screening of eutectic auxiliary materials

[0095] 95.00g of β-carotene crystals and 5.00g of eutectic auxiliary materials (12-polyglycerol fatty acid ester, hexaglycerol fatty acid ester, monoester sucrose fatty acid ester, polydextrose, trehalose, curcumin, epigallocatechin gallate, α-tocopherol, ascorbyl palmitate) were added to a twin-screw extruder (TSE 20, Brabender, Germany) for hot-melt extrusion treatment, the screw speed was set to 50rpm, the feed rate was set to 15rpm, the material inlet temperature was set to 190°C, the outlet temperature was set to 100°C, and the β-carotene hot-melt extrudate was directly dropped into the liquid nitrogen prepared in advance to rapidly cool and solidify. The β-carotene hot-melt extrudate was pulverized, and the pulverized material was passed through a 100-mesh screen to obtain β-carotene hot-melt extruded powder.

[0096] The control group is a β-carotene hot melt extrudate obtained without adding any eutectic auxiliary materials.

[0097] The retention rate of β-carotene and the ratio of cis-isomers in β-carotene hot melt extruded powder were determined by X-ray diffractometer (see the exemplary X-ray diffraction results for details). Figure 1 ).

[0098] The results are shown in Table 1.

[0099] Table 1 Effect of the types of co-melting auxiliary materials in Example 1 on the physical and chemical parameters of hot melt extruded β-carotene

[0100]

[0101]

[0102] The results show:

[0103] (1) The results of the control group showed that a. after hot melt extrusion, the β-carotene crystal sequence was rearranged, the crystal order was greatly weakened, and its relative crystallinity was significantly reduced from 95.70% to 30.45%; b. the high temperature during hot melt extrusion caused partial oxidation and degradation of β-carotene, and the retention rate was only 45.63%.

[0104] (2) The inventors unexpectedly found that, compared with the control group, when the eutectic excipient contained an emulsifier, it could promote the amorphization of β-carotene crystals. In particular, when the emulsifier polyglycerol fatty acid ester was used as the eutectic excipient, the relative crystallinity of the β-carotene hot melt extruded powder was further reduced to 21.73%.

[0105] (3) Compared with the control group, when the eutectic excipients contained antioxidants, the retention rate of β-carotene could be significantly improved, especially when the fat-soluble antioxidants α-tocopherol and ascorbyl palmitate were used as eutectic excipients, the retention rate of β-carotene hot-melt extruded powder exceeded 80%.

[0106] Therefore, dodecaglycerol fatty acid ester, α-tocopherol and ascorbyl palmitate were selected as eutectic excipients, and the effect of eutectic extrusion on the retention rate, isomer structure and relative crystallinity of β-carotene was further studied.

[0107] Example 2: Screening of the amount of eutectic auxiliary materials added

[0108] β-carotene crystals and eutectic auxiliary materials (12-polyglycerol fatty acid ester, α-tocopherol, ascorbyl palmitate) were mixed in different mass ratios and added to a twin-screw extruder (TSE 20, Brabender, Germany) for hot-melt extrusion. The screw speed was set to 50 rpm, the feed rate was set to 15 rpm, the material inlet temperature was set to 190° C., and the outlet temperature was set to 100° C. The β-carotene hot-melt extrudate was directly dropped into the liquid nitrogen prepared in advance to rapidly cool and solidify. The β-carotene hot-melt extrudate was crushed, and the crushed material was passed through a 100-mesh screen. The obtained hot-melt extruded powder was measured for the β-carotene retention rate and the cis-isomer ratio to optimize the addition amount of the eutectic auxiliary materials.

[0109] The mass ratios of β-carotene crystals and eutectic auxiliary materials are 19:1, 9:1, and 6:1, respectively. The eutectic auxiliary materials are the preferred dodecaglycerol fatty acid ester, α-tocopherol, and ascorbyl palmitate in Example 1.

[0110] The results are shown in Table 2.

[0111] Table 2 Effect of the amount of co-melting auxiliary materials added in Example 2 on the physical and chemical parameters of hot melt extruded β-carotene

[0112]

[0113]

[0114] The results show:

[0115] The addition amount of different eutectic excipients has an important influence on the physicochemical parameters of hot melt extruded β-carotene.

[0116] (1) The addition of different amounts of polyglycerol fatty acid esters had little effect on the retention rate and cis-isomer ratio of β-carotene, and the mass ratio of the two was less than or equal to 9:1, which could effectively reduce the relative crystallinity of β-carotene. This result shows that polyglycerol fatty acid esters are beneficial to the dispersion and amorphization of β-carotene.

[0117] (2) When the mass ratio of β-carotene to eutectic excipients in the β-carotene / α-tocopherol and β-carotene / ascorbyl palmitate groups was reduced from 19:1 to 9:1, the β-carotene retention rate was significantly improved; when the mass ratio of β-carotene to eutectic excipients was further reduced to 6:1, the β-carotene retention rate did not increase further. These results show that the addition of fat-soluble antioxidants can effectively alleviate the oxidative degradation of β-carotene.

[0118] In summary, 9:1 was selected as the mass ratio of β-carotene and eutectic excipients for further experiments.

[0119] Examples 3 to 9, Comparative Example 1

[0120] The effects of hot melt extruded β-carotene prepared with different eutectic excipients on the physicochemical parameters of β-carotene in the prepared β-carotene microcapsules were detected.

[0121] The preparation methods of the β-carotene microcapsules of Examples 3 to 9 are as follows (reference Figure 2 ):

[0122] a) Add a mixture of 90.00 g of β-carotene crystals and 10.00 g of eutectic auxiliary materials (Table 3) into a twin screw extruder (TSE 20, Brabender, Germany) for hot melt extrusion treatment, the screw speed is set to 30-80 rpm (50 rpm for Example 3, 80 rpm for Example 4, 30 rpm for Example 5, and 30 rpm for Example 6), the feed rate is set to 15 rpm, the material inlet temperature is set to 180-195° C. (195° C. for Example 3, 182° C. for Example 4, 180° C. for Example 5, and 180° C. for Example 6), the outlet temperature is set to 95-100° C. (100° C. for Example 3, 95° C. for Example 4, 97° C. for Example 5, and 97° C. for Example 6), and the β-carotene hot melt extrudate is directly dropped into the liquid nitrogen prepared in advance to rapidly cool and solidify. The β-carotene hot melt extrudate is pulverized, and the pulverized material is passed through a 100 mesh screen for standby use.

[0123] Among them, in Example 5 and Example 6, in order to prevent the β-carotene crystals from agglomerating before extrusion, 1) α-tocopherol is added last; 2) α-tocopherol is added by dissolving α-tocopherol in 3 times the mass of anhydrous ethanol, and attaching α-tocopherol to the surface of β-carotene crystal particles by spraying.

[0124] b) 14 g of OSA modified starch was dispersed in 400 mL of deionized water and magnetically stirred at 600 rpm in a water bath at 80°C until completely dissolved. Then, 5 g of β-carotene hot melt extrudate and 1 g of antioxidant (Table 3) were slowly added to the OSA modified starch solution, and a high-speed shearing machine was used to shear at 8000 rpm until the material was completely dispersed to obtain a β-carotene crude dispersion.

[0125] c) injecting the β-carotene crude dispersion obtained in step b) into a grinder (FSW-1.0, Shanghai Yile Electromechanical) containing 2.5kg zirconium oxide beads (diameter 0.4-0.6mm), and turning on the circulating water cooler to prevent the grinding liquid temperature from being too high. During the grinding process, the grinding speed is 1800-2700rpm (1800rpm for Example 3, 2100rpm for Example 4, 2400rpm for Example 5, and 2700rpm for Example 6), the grinding temperature is about 22-28°C (22°C for Example 3, 24°C for Example 4, 26°C for Example 5, and 28°C for Example 6), and the grinding time is 90-120min (90min for Example 3, 120min for Example 4, 180min for Example 5, and 210min for Example 6), to obtain a β-carotene nano dispersion.

[0126] d) After grinding, the β-carotene nano-dispersion obtained in step c) is subjected to spray drying treatment, wherein the feed rate is 300 mL / h, the spray drying air inlet temperature is 105-145° C. (105° C. in Example 3, 115° C. in Example 4, 135° C. in Example 5, and 145° C. in Example 6), and the outlet temperature is 70-80° C. (70° C. in Example 3, 75° C. in Example 4, 80° C. in Example 5, and 80° C. in Example 6), to obtain β-carotene microcapsules.

[0127] e) Detect the physical and chemical indicators of the rehydrated dispersion of β-carotene microcapsules, such as particle size, embedding efficiency, loading rate and cis-isomer ratio.

[0128] The preparation method of β-carotene microcapsules in Comparative Example 1 is as follows:

[0129] a) β-carotene microcapsules were prepared by a single wet grinding process. First, 14 g of OSA modified starch was dispersed in 400 mL of deionized water and magnetically stirred at 600 rpm in an 80°C water bath until completely dissolved. Then, 5 g of β-carotene crystals, 0.25 g of ascorbyl palmitate, 0.25 g of tea polyphenols, and 0.5 g of sodium L-ascorbate were slowly added to the OSA modified starch solution, and a high-speed shearing machine was used to shear at 8000 rpm until the material was completely dispersed to obtain a β-carotene crude dispersion.

[0130] b) injecting the β-carotene crude dispersion obtained in step a) into a grinder (FSW-1.0, Shanghai Yile Electromechanical) containing 2.5 kg of zirconium oxide beads (diameter 0.4-0.6 mm), and turning on a circulating water cooler to prevent the temperature of the ground dispersion from being too high. The grinding speed during the grinding process is 1800 rpm, the grinding temperature is about 22° C., and the grinding time is 90 min.

[0131] c) After grinding, the obtained β-carotene nano-dispersion liquid was spray-dried, wherein the feed rate was 300 mL / h, the spray drying air inlet temperature was 105° C., and the outlet temperature was 70° C., to obtain β-carotene microcapsules.

[0132] d) Detect the physical and chemical indicators of the rehydrated dispersion of β-carotene microcapsules, such as particle size, embedding efficiency, loading rate and cis-isomer ratio.

[0133] The components and contents of the eutectic auxiliary materials in Examples 3 to 9 and Comparative Example 1, and the formula of the β-carotene crude dispersion are shown in Table 3. The results of the physical and chemical index test of the β-carotene microcapsules are shown in Table 4. The X-ray diffraction results of the β-carotene microcapsules in Example 3 and Comparative Example 1 are shown in Table Figure 3 .

[0134] Table 3 Components and contents of eutectic auxiliary materials in Examples 3 to 9 and Comparative Example 1, and formula of β-carotene crude dispersion

[0135]

[0136] Table 3 Physical and chemical index test results of β-carotene microcapsules of Examples 3 to 9 and Comparative Example 1

[0137]

[0138]

[0139] The above results show that: (1) Compared with Comparative Example 1, after the β-carotene crystal raw material and the emulsifier polyglycerol fatty acid ester, the fat-soluble antioxidant α-tocopherol, and ascorbyl palmitate were co-melted and extruded, the β-carotene microcapsules obtained had a significantly increased β-carotene cis-isomer ratio, and the obtained microcapsules had a high β-carotene embedding rate, a rehydrated dispersion liquid particle size of 280 to 330 nm, and a small β-carotene particle size (Table 3). (2) Example 3 The β-carotene microcapsules prepared by the hot melt extrusion and wet grinding coupling process had almost no diffraction peaks and were amorphous ( Figure 3 ).

[0140] The above results indicate that the β-carotene microcapsules of the present invention have high bioaccessibility and good solubility.

[0141] The inventors further specifically investigated the solubility and bioaccessibility of β-carotene in the β-carotene microcapsules of Examples 3 to 6 and Comparative Example 1. The results are shown in Figure 4 .

[0142] The results show that compared with Comparative Example 1, the solubility and bioaccessibility of β-carotene in the β-carotene microcapsules of Examples 3 to 6 of the present invention are significantly enhanced.

[0143] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing low-crystalline β-carotene, characterized in that: The method comprises: The β-carotene crystal raw material is subjected to hot melt extrusion treatment to obtain a β-carotene hot melt extrudate; The beta-carotene hot melt extrudate is pulverized to obtain the low-crystalline beta-carotene.

2. The method according to claim 1, characterized in that subjecting the mixture of the β-carotene crystal raw material and the eutectic auxiliary material to the hot melt extrusion process; Optionally, the eutectic auxiliary material is selected from at least one of an emulsifier, a polysaccharide, and an antioxidant; Optionally, the emulsifier is selected from at least one of polyglycerol fatty acid esters, monoester sucrose fatty acid esters, and stearic acid glyceryl ester; Further, the emulsifier is selected from at least one of 12-polyglycerol fatty acid esters, 10-polyglycerol fatty acid esters, 8-polyglycerol fatty acid esters, 6-polyglycerol fatty acid esters, 3-polyglycerol fatty acid esters, sucrose fatty acid monoesters, sucrose fatty acid diesters, sucrose fatty acid triesters, sucrose fatty acid polyesters, glyceryl monostearate, glyceryl distearate, glyceryl tristearate, acetylated mono- and diglyceryl fatty acid esters, calcium stearate, and sodium stearoyl lactylate; Optionally, the polysaccharide is selected from at least one of polydextrose, trehalose, sucrose, maltose, hydroxypropyl methylcellulose, carboxymethyl cellulose, ethyl cellulose, tuckahoe polysaccharide, amino polysaccharide, chitin, agar, hyaluronic acid, and inulin; Optionally, the antioxidant is selected from at least one of curcumin, epigallocatechin gallate, resveratrol, α-tocopherol, ascorbyl palmitate, tea polyphenol palmitate, D-ascorbic acid and its sodium salt, tea polyphenols, theaflavins, and rosemary extract.

3. The method according to claim 2, characterized in that The eutectic auxiliary material comprises: at least one of: dodecaglycerol fatty acid ester, decaglycerol fatty acid ester, octaglycerol fatty acid ester, hexaglycerol fatty acid ester, polydextrose, trehalose, curcumin, epigallocatechin gallate, α-tocopherol, and ascorbyl palmitate; Optionally, the eutectic auxiliary material comprises: dodecaned glycerol fatty acid ester and / or α-tocopherol and / or ascorbyl palmitate; Optionally, the mass ratio of the β-carotene crystal raw material to the eutectic auxiliary material is (5-20):1, preferably (5-10):1, more preferably (6-9):1; Optionally, when the eutectic auxiliary material comprises α-tocopherol, the α-tocopherol is dissolved in an organic solvent to obtain an α-tocopherol solution, and the α-tocopherol solution is subjected to surface contact treatment with the β-carotene crystals to obtain the mixture; Optionally, the organic solvent is anhydrous ethanol, and the mass ratio of α-tocopherol to anhydrous ethanol is 1:(2-4); Optionally, the surface contact treatment comprises: spraying the α-tocopherol solution onto the surface of the β-carotene crystals.

4. The method according to claim 1, characterized in that The material inlet temperature of the hot melt extrusion process is 150-200°C, and the outlet temperature is 80-120°C; Furthermore, the material inlet temperature of the hot melt extrusion process is 180-195°C, and the outlet temperature is 95-100°C; Optionally, before the pulverization process, the β-carotene hot melt extrudate is subjected to a cooling and solidification process; Optionally, the cooling and solidification treatment comprises: contacting the β-carotene hot melt extrudate with liquid nitrogen; Optionally, the pulverized product obtained after the pulverization treatment is passed through a 60-200 mesh sieve to obtain the low-crystalline β-carotene, preferably 80-100 mesh.

5. A low-crystalline β-carotene, characterized in that: The low-crystalline β-carotene is prepared by the method according to any one of claims 1 to 4; Optionally, in the low-crystalline β-carotene, the relative crystallinity of β-carotene is less than 35%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 30%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 29%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 28%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 27%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 26%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 25%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 22%; Furthermore, the relative crystallinity of the β-carotene is less than or equal to 20%; Optionally, the cis-isomer ratio of the β-carotene is greater than or equal to 40%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 46%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 50%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 55%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 60%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 63%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 64%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 65%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 66%; Furthermore, the cis-isomer ratio of the β-carotene is greater than or equal to 67%.

6. A β-carotene dispersion, characterized in that: The dispersion comprises: the low-crystalline β-carotene according to claim 5, an emulsifier, and an antioxidant.

7. The β-carotene dispersion according to claim 6, characterized in that The emulsifier is selected from at least one of sodium starch octenylsuccinate, sodium carboxymethyl cellulose, sodium caseinate, soybean polysaccharide, gum arabic, maltodextrin, whey protein isolate, soybean protein isolate, tea saponin and Tween; Optionally, the antioxidant is selected from at least one of BHA, BHT, ethoxyquin, TBHQ, tea polyphenols, α-tocopherol, ascorbic acid, sodium L-ascorbate, ascorbyl palmitate, sodium D-isoascorbate, and rosemary extract; Optionally, the content of the antioxidant is 10 to 30% based on the mass of the low-crystalline β-carotene; Optionally, the mass ratio of the low-crystalline β-carotene, emulsifier, and antioxidant is (3-7):(10-20):(0.8-1.2), preferably 5:(12-16):1, more preferably 5:14:1; Optionally, the emulsifier is sodium starch octenylsuccinate; Optionally, the antioxidant comprises: ascorbyl palmitate, tea polyphenols and sodium L-ascorbate; Optionally, the mass ratio of ascorbyl palmitate, tea polyphenols and sodium L-ascorbate is 1:1:2; Optionally, the dispersion is an emulsion or a suspension.

8. A β-carotene product, characterized in that: The product comprises: the low-crystalline β-carotene according to claim 5 or the β-carotene dispersion according to any one of claims 6 to 7; Optionally, the β-carotene preparation is β-carotene microcapsules.

9. A method for preparing β-carotene microcapsules, characterized in that: The method comprises: Low-crystalline β-carotene is prepared according to the method according to any one of claims 1 to 4.

10. The method according to claim 9, characterized in that The method further comprises: Dispersing the low-crystalline β-carotene with the emulsifier and antioxidant according to any one of claims 6 to 7 to obtain a β-carotene dispersion; The β-carotene dispersion is subjected to spray drying to obtain the β-carotene microcapsules; Optionally, before the spray drying treatment, the β-carotene dispersion is wet-ground to obtain a nano-scale β-carotene dispersion; Optionally, the wet grinding has a rotation speed of 1500-3500 rpm, a time of 1-5 h, and a temperature of 18-28 ° C; preferably, the rotation speed is 1800-2700 rpm, the time is preferably 1.5-2 h, and the temperature is preferably 22-28 ° C; Optionally, the air inlet temperature of the spray drying process is 105-165°C, the air outlet temperature is 60-80°C, and the feed rate is 100-500mL / h; the air inlet temperature is preferably 105-145°C, the air outlet temperature is preferably 70-80°C, and the feed rate is preferably 300-400mL / h.

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