Amphiphilic adsorbent for reducing cholesterol content of beef tallow and preparation method thereof

Abstract

The invention provides an amphiphilic adsorbent for reducing the cholesterol content of beef tallow as well as a preparation method and application of the amphiphilic adsorbent. The adsorbent adopts a core-shell structure microsphere design, a core layer of the adsorbent is food-grade diatomite modified by a silane coupling agent, and a shell layer of the adsorbent is a cyclodextrin-pectin composite system. The composite shell layer is composed of an amphiphilic cyclodextrin mixture and an amphiphilic network, wherein the amphiphilic cyclodextrin mixture is composed of hydroxypropyl-beta-cyclodextrin and octyl-beta-cyclodextrin, and the amphiphilic network is formed by cross-linking oleic acid grafted low-methoxyl pectin and inulin through calcium ions. The preparation method comprises the key steps of diatomite modification, shell gel solution preparation, core-shell structure self-assembly and the like. By regulating and controlling the mass ratio of the components and the reaction conditions, the amphiphilic microspheres with both hydrophilic and hydrophobic areas are successfully constructed. The adsorbent can specifically target and efficiently remove cholesterol in beef tallow.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food processing, and particularly relates to a high-efficiency food cholesterol removal functional material. BACKGROUND

[0002] As an important raw material for traditional food industry, beef tallow is widely used in hotpot condiments, pastries and catering industry due to its unique flavor and processing characteristics. However, the high cholesterol content (about 100-150 mg / 100g) in beef tallow is one of the main health concerns. Long-term excessive intake of cholesterol, especially low-density lipoprotein cholesterol, is an important risk factor for causing atherosclerosis, coronary heart disease and other cardiovascular and cerebrovascular diseases. With the continuous enhancement of consumers' health awareness, developing an effective technology to reduce cholesterol in beef tallow has urgent practical significance for improving the nutritional quality and market competitiveness of beef tallow.

[0003] At present, the methods for reducing cholesterol in edible oils and fats mainly include physical refining method, chemical esterification method, biological degradation method and adsorption separation method. Among them, the adsorption separation method is considered to be one of the most promising technologies due to its mild operating conditions, little effect on the nature of the oil and fat itself, and high potential safety. Among the many cholesterol removal technologies, the β-cyclodextrin (β-CD) inclusion method shows great application potential due to its high efficiency, specificity and easy operation. β-CD is a cyclic oligosaccharide composed of 7 glucose units connected by α-1, 4-glycosidic bonds. Its molecule has a unique "outer hydrophilic and inner hydrophobic" conical cavity structure. This structure enables it to selectively include hydrophobic small molecules such as cholesterol (Chol) by hydrophobic interaction and van der Waals force. β-CD can form an inclusion complex with cholesterol in oil, which is insoluble in oil, and then remove it from oil by centrifugation, with a removal rate of more than 90%. However, there are significant technical bottlenecks in directly applying natural β-cyclodextrin to cholesterol removal in beef tallow. First, the solubility of natural β-cyclodextrin in aqueous phase is limited, which limits its inclusion reaction efficiency in solution. Second, its single hydrophobic cavity is not ideal in terms of adsorption capacity and selectivity when facing complex beef tallow system. More importantly, beef tallow is a non-polar hydrophobic system, while the hydrophilicity of the outer wall of natural cyclodextrin makes it difficult to effectively disperse and contact in oil phase, greatly limiting its application effect in actual oil system.

[0004] To overcome these defects, existing research has made some attempts. For example, hydroxypropyl modification is made to cyclodextrin to improve its water solubility, or it is compounded with porous materials such as diatomite to improve the specific surface area. However, these improvement schemes often only solve a single problem: improving water solubility does not improve its compatibility in the oil phase; simple physical compounding fails to build a synergistic amphiphilic interface, and the stability and mechanical strength of the composite material are insufficient. In addition, the existing technology lacks fine regulation of the microstructure of the adsorbent, and fails to create an amphiphilic microenvironment that can both well infiltrate the beef tallow and efficiently fix the cholesterol molecules. Therefore, developing a new type of composite adsorbent with a clear core-shell structure, which can simultaneously consider hydrophilic and lipophilic properties, and synergistically enhance through multiple forces, is the key to breaking through the current technical bottleneck. SUMMARY

[0005] The technical problem to be solved: The purpose of the present application is to provide an amphiphilic adsorbent for reducing the cholesterol content of beef tallow. In the prior art, when using natural β-cyclodextrin to remove cholesterol from beef tallow, there are two major problems of low adsorption efficiency and poor oil phase compatibility.

[0006] Technical scheme: An amphiphilic adsorbent for reducing the cholesterol content of beef tallow, the adsorbent is a core-shell structure microsphere, the core layer is food-grade diatomite modified by a silane coupling agent; the shell layer is a cyclodextrin-pectin composite system, which is composed of an amphiphilic cyclodextrin mixture of hydroxypropyl-β-cyclodextrin and octyl-β-cyclodextrin, and an amphiphilic network formed by oleic acid grafted low methoxyl pectin and inulin crosslinked by calcium ions.

[0007] The preparation method of the above-mentioned amphiphilic adsorbent comprises the following steps: S1. Refluxing food-grade diatomite with 1-5% silane coupling agent in ethanol solution for 2-3h, and then washing and drying the product to obtain modified diatomite; S2. Dissolving hydroxypropyl-β-cyclodextrin, octyl-β-cyclodextrin, oleic acid grafted low methoxyl pectin and inulin in deionized water in proportion, and adding CaCl2 to form a shell layer gel solution; S3. Redispersing the modified diatomite obtained in step S1 in deionized water to obtain a core layer dispersion; S4. Under continuous stirring, the shell layer solution prepared in step S2 is added dropwise into the core layer dispersion of step S3, and the mass ratio of modified diatomite to shell layer material is controlled to be 1:(2-5), and stirring at room temperature for 2-6h until the shell layer molecules self-assemble on the surface of diatomite to obtain core-shell structure adsorbent microspheres.

[0008] Preferably, in step S2, the mass ratio of hydroxypropyl-β-cyclodextrin to octyl-β-cyclodextrin is (1-5):1; and / or, The mass ratio of the said inclusion mixture of parent cyclodextrin and oleic acid grafted low methoxyl pectin is (0.2~4):1 and / or, The mass ratio of the said oleic acid grafted low methoxyl pectin and inulin is (4~5):1.

[0009] Preferably, the silane coupling agent in the step S1 is at least one of KH-550 and KH-560; and / or, The reflux temperature is 70~85℃.

[0010] Preferably, the adding amount of CaCl2 in the step S2 is 1~3% of the total mass of the shell material.

[0011] Preferably, the preparation method of the said octyl-β-cyclodextrin comprises the following steps: S11. Dissolve β-cyclodextrin in 5%-10% NaOH solution, control the mass ratio of β-cyclodextrin and NaOH to be 1:(0.5~1), and carry out stirring activation at room temperature under nitrogen protection; S12. Slowly add the ethanol solution of brominated octane with a concentration of 20%-50% to the activated solution obtained in step S11, control the molar ratio of brominated octane to glucose units in β-cyclodextrin to be (0.5~1.5):1, and continue to react at 60~75℃ for 4~8h; S13. After the reaction in step S12 is completed, cool the reaction solution to room temperature, neutralize it to neutral with dilute hydrochloric acid, then place it in a dialysis bag and dialyze it with deionized water for 48~72h; freeze dry the dialyzed solution at-50℃~-70℃ for 16~24h to obtain octyl-β-cyclodextrin powder with a degree of substitution of 0.1~0.3.

[0012] Preferably, the preparation method of the said hydroxypropyl-β-cyclodextrin comprises the following steps: S21. Dissolve β-cyclodextrin in deionized water, add alkali liquor under stirring to adjust the pH of the system to 9~11 to obtain an alkaline β-cyclodextrin solution; S22. Slowly add propylene oxide to the solution obtained in step S21, control the molar ratio of propylene oxide to β-cyclodextrin to be (5~10):1, and carry out hydroxypropylation reaction at 40~60℃ for 6~12h; S23. After the reaction in step S22 is completed, cool the reaction solution to room temperature, neutralize it to neutral with acid liquor, then place it in a dialysis bag and dialyze it with deionized water for 48~72h; freeze dry the dialyzed solution to obtain hydroxypropyl-β-cyclodextrin powder with a degree of substitution of 0.5~1.0.

[0013] Preferably, the preparation method of the said oleic acid grafted low methoxyl pectin comprises the following steps: S31. Disperse the protopectin in a citric acid buffer solution with pH = 3.5~4.5, prepare a dispersion liquid with mass concentration of 5%~10%, add pectin methylesterase with 0.5%~2% of the mass of the protopectin, and enzymatically hydrolyze at 40~50℃ for 2~4h; S32. Heat the reaction liquid obtained in step S31 to 85~95℃ for 10~20min to inactivate the enzyme, precipitate after cooling with anhydrous ethanol, and obtain low methoxyl pectin after washing with ethanol; S33. Disperse the low methoxyl pectin obtained in step S32 in anhydrous pyridine, add oleic anhydride, control the mass ratio of low methoxyl pectin to oleic anhydride to be 1:(0.2~0.5), and stir at 60~80℃ for 2~4h; S34. Cool the reaction liquid obtained in step S33 to room temperature, slowly pour into anhydrous ethanol under stirring for precipitation, collect the precipitate and repeatedly wash with anhydrous ethanol for 3~5 times, and finally vacuum dry to obtain oleic acid grafted low methoxyl pectin.

[0014] Application of a dual parent adsorbent in removing cholesterol from beef tallow.

[0015] Beneficial effects: The dual parent adsorbent has the following advantages: 1. The unique core-shell structure and dual parent shell design combine the physical adsorption of diatomite and the host-guest inclusion effect of cyclodextrin, which can synergistically and efficiently target capture cholesterol molecules in beef tallow, significantly improving the removal rate.

[0016] 2. The octyl-β-cyclodextrin and oleic acid grafted segments in the shell endow the adsorbent with good lipophilicity, enabling it to better disperse and infiltrate in the hydrophobic beef tallow system, thereby fully contacting with cholesterol molecules, overcoming the problem of limited application of traditional hydrophilic materials in oil phase.

[0017] 3. The modified diatomite as the rigid core and the pectin-inulin network crosslinked by calcium ions as the shell form a stable microsphere structure, ensuring that the adsorbent is not easily disintegrated during stirring, centrifugation and other processes, and has good mechanical durability.

[0018] 4. All raw materials (diatomite, cyclodextrin, pectin, inulin, etc.) are food-grade or edible ingredients, and the preparation process is mild, avoiding the use of toxic and harmful reagents, and ensuring the safety basis for application in the food industry. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Example 1: Removal of cholesterol in beef tallow systems with different water contents; Figure 2 Comparative Example 9: Removal of cholesterol in beef tallow systems with different water contents; Figure 3Example 11 for removing cholesterol in the system of different water content of beef tallow; Figure 4 Viscosity test of beef tallow; Figure 5 CLSM image. DETAILED DESCRIPTION

[0020] The application will be further described in conjunction with the following examples, which are illustrative of the application but not limit the application to the following examples: The application provides a kind of amphiphilic adsorbent for reducing the cholesterol content of beef tallow, the amphiphilic adsorbent is a core-shell structure microsphere, the core layer uses food grade diatomite modified by silane coupling agent as core layer, the surface hydrophilic and hydrophobic of modified diatomite is regulated, and it itself has abundant porous structure, not only provides stable skeleton support for adsorbent, improves the overall mechanical stability, but also can preliminarily capture cholesterol molecules in beef tallow through the physical adsorption of porous structure;The shell layer is a cyclodextrin-pectin composite system, which is composed of amphiphilic cyclodextrin mixture of hydroxypropyl-β-cyclodextrin and octyl-β-cyclodextrin, and the amphiphilic network formed by oleic acid grafted low methoxyl pectin and inulin crosslinked by calcium ions, the cyclodextrin-pectin composite system is constructed as the shell layer, wherein the amphiphilic cyclodextrin mixture of hydroxypropyl-β-cyclodextrin and octyl-β-cyclodextrin can be included with cholesterol by virtue of the unique cavity structure of cyclodextrin, and the amphiphilic property enables it to adapt to the oil phase environment of beef tallow, and enhances the affinity with cholesterol molecules;The amphiphilic network formed by oleic acid grafted low methoxyl pectin and inulin crosslinked by calcium ions further optimizes the structural stability and amphiphilic adsorption capacity of the shell layer, the crosslinking action of calcium ions makes the network structure more dense and not easy to disintegrate, and the hydrophobicity given by oleic acid grafting and the hydrophilicity of pectin and inulin itself form a synergy, which can capture cholesterol molecules from different interfaces. The synergistic effect of core-shell structure significantly improves the adsorption efficiency of adsorbent for cholesterol in beef tallow.

[0021] The preparation method of the above-mentioned amphiphilic adsorbent comprises the following steps: S1. reflux food grade diatomite and 1-5% mass fraction of KH-550 or KH-560 silane coupling agent in 70-85℃ ethanol solution for 2-3h, and the product is washed and dried to obtain modified diatomite; S2. dissolve hydroxypropyl-β-cyclodextrin, octyl-β-cyclodextrin, oleic acid grafted low methoxyl pectin and inulin in deionized water according to the proportion, add CaCl2 and stir to form a shell layer gel solution; S3. disperse the modified diatomite obtained in step S1 in deionized water to obtain a core layer dispersion; S4. Under continuous stirring, the shell layer solution prepared in step S2 is added dropwise into the core layer dispersion prepared in step S3, and the mass ratio of the modified diatomite to the shell layer material is controlled to be 1:(2-5), and stirring is performed at room temperature for 2-6 hours until the shell layer molecules are self-assembled on the surface of the diatomite to obtain core-shell structure adsorbent microspheres.

[0022] In the step S1, the food-grade diatomite is modified by using the silane coupling agent KH-550 or KH-560, and the ethanol solution is used as a dispersion medium to ensure the uniformity of the reaction, and refluxing for 2-3 hours can ensure that the silane coupling agent is fully grafted onto the surface of the diatomite.

[0023] In the step S2, the mixture of the amphiphilic cyclodextrin and the amphiphilic network component are dissolved in water, preferably, the mass ratio of the hydroxypropyl-β-cyclodextrin to the octyl-β-cyclodextrin is (1-5):1, the mass ratio of the mixture of the amphiphilic cyclodextrin to the oleic acid grafted low-methoxyl pectin is (0.2-4):1, and the mass ratio of the oleic acid grafted low-methoxyl pectin to the inulin is (4-5):1; after adding CaCl2, preferably, the amount of the CaCl2 added is 1-3% of the total mass of the shell layer material, and the calcium ions can crosslink with the carboxyl groups in the low-methoxyl pectin to quickly form a stable shell gel solution. This step completes the mixing and gelation of the functional components of the shell layer at one time, simplifies the preparation process, and provides a stable structure basis for the subsequent self-assembly, ensuring that the amphiphilic properties of the shell layer are fully retained. In the step S3, the modified diatomite is dispersed in deionized water, which can uniformly disperse the modified diatomite particles and avoid particle agglomeration, providing a prerequisite for uniform coating of the shell layer in the subsequent step, and ensuring that the finally formed core-shell microspheres have uniform particle size and stable structure. In the step S4, the mass ratio of the modified diatomite to the shell layer material is controlled to be 1:(2-5), which can ensure that the shell layer has an appropriate thickness, and neither the adsorption performance is insufficient due to the shell layer being too thin, nor the material is wasted due to the shell layer being too thick. The shell layer solution is added dropwise under continuous stirring, and stirring is performed at room temperature for 2-6 hours, which can promote the shell layer molecules to fully self-assemble on the surface of the diatomite through electrostatic interaction, hydrogen bonding and other interactions, forming a complete and uniform core-shell structure, and finally obtaining an amphiphilic adsorbent microsphere with excellent adsorption performance.

[0024] Preferably, the preparation method of the octyl-β-cyclodextrin comprises the following steps: S11. β-cyclodextrin is dissolved in 5%-10% NaOH solution, the mass ratio of β-cyclodextrin to NaOH is controlled to be 1:(0.5-1), and stirring is performed at room temperature under nitrogen protection. S12. Slowly add the bromooctane ethanol solution with a concentration of 20%~50% to the activated solution obtained in step S11, control the molar ratio of bromooctane to glucose units in β-cyclodextrin to be (0.5~1.5):1, and continue the reaction at 60~75℃ for 4~8h; S13. After the reaction in step S12 is completed, cool the reaction solution to room temperature, neutralize it to neutral with dilute hydrochloric acid, and then place it in a dialysis bag for dialysis with deionized water for 48~72h; freeze-dry the dialyzed solution at-50℃~-70℃ for 16~24h to obtain octyl-β-cyclodextrin powder with a degree of substitution of 0.1~0.3.

[0025] The NaOH solution in step S11 above provides an alkaline activation environment for β-cyclodextrin, and the mass ratio control ensures that the hydroxyl groups in the β-cyclodextrin molecules are fully activated and the reaction sites are exposed; nitrogen protection can isolate air to avoid impurities interfering with the activation process, and room temperature stirring can ensure uniform activation and avoid overreaction; In step S12, bromooctane is used as a hydrophobic modifier, and an ethanol solution can improve its compatibility with the activated solution; slow addition can avoid local high concentration leading to uneven substitution; a temperature range of 60~75℃ can ensure a moderate reaction rate, speeding up the reaction while preventing the volatilization of reactants, and a reaction time of 4~8h ensures that the substitution reaction proceeds sufficiently; In step S13, neutralization to neutral after cooling to room temperature can terminate the reaction and avoid the influence of the alkaline environment on subsequent processing; dialysis for 48~72h can completely remove unreacted bromooctane, salts and other impurities; freeze-drying can quickly lock the product structure and avoid damage to the active ingredients, and finally obtain the target product with high purity.

[0026] Preferably, the preparation method of the hydroxypropyl-β-cyclodextrin comprises the following steps: S21. Dissolve β-cyclodextrin in deionized water, add alkali under stirring to adjust the pH of the system to 9~11 to obtain an alkaline β-cyclodextrin solution; S22. Slowly add the propylene oxide of USP f101929 to the solution obtained in step S21, control the molar ratio of propylene oxide to β-cyclodextrin to be (5~10):1, and perform hydroxypropylation at 40~60℃ for 6~12h; S23. After the reaction in step S22 is completed, cool the reaction solution to room temperature, neutralize it to neutral with an acid solution, and then place it in a dialysis bag for dialysis purification with deionized water for 48~72h; freeze-dry the dialyzed solution to obtain hydroxypropyl-β-cyclodextrin powder with a degree of substitution of 0.5~1.0.

[0027] The pH control in the alkaline range of 9-11 in the above step S21 is to activate the hydroxyl group in the β-cyclodextrin molecule, so that it is more prone to nucleophilic reaction with subsequent propylene oxide, and to provide active sites for hydroxypropylation; The propylene oxide in step S22 is selected as the hydroxypropylation reagent to ensure food-grade safety of USP grade; slow addition can prevent local reaction from being too violent, causing uneven substitution, and a temperature of 40-60°C can ensure the reaction rate and avoid volatilization of propylene oxide due to excessive temperature; a reaction time of 6-12h ensures that the hydroxypropylation reaction proceeds sufficiently.

[0028] The dialysis for 48-72h in step S23 can completely remove unreacted propylene oxide, salt and other impurities, ensuring that the product purity meets the food-grade requirements; freeze-drying can maximize the retention of product structure and avoid performance changes caused by high-temperature drying, ultimately obtaining a high-purity target product.

[0029] Preferably, the preparation method of the oleic acid grafted low-methoxyl pectin comprises the following steps: S31. Disperse the original pectin in a citric acid buffer solution with a pH of 3.5-4.5 to prepare a dispersion liquid with a mass concentration of 5%-10%, and add pectin methylesterase in an amount of 0.5%-2% of the mass of the original pectin, and enzymatically hydrolyze at 40-50°C for 2-4h; S32. Heat the reaction liquid obtained in step S31 to 85-95°C for 10-20min to inactivate the enzyme, and then precipitate with anhydrous ethanol after cooling, and wash with ethanol to obtain low-methoxyl pectin; S33. Disperse the low-methoxyl pectin obtained in step S32 in anhydrous pyridine, add 24909-72-6 oleic anhydride, control the mass ratio of low-methoxyl pectin to oleic anhydride to be 1:(0.2-0.5), and stir at 60-80°C for 2-4h; S34. Cool the reaction liquid obtained in step S33 to room temperature, slowly pour into anhydrous ethanol under stirring for precipitation, collect the precipitate and wash repeatedly with anhydrous ethanol for 3-5 times, and finally vacuum dry to obtain the oleic acid grafted low-methoxyl pectin.

[0030] The citric acid buffer solution in the above step S31 can stabilize the pH of the system, and a pH of 3.5-4.5 is the optimal action environment for pectin methylesterase; a mass concentration of 5%-10% can ensure the efficiency of enzymatic hydrolysis while avoiding excessive viscosity of the system; an enzyme addition amount of 0.5%-2% can ensure the effect of enzymatic hydrolysis while avoiding waste; and a temperature of 40-50°C is the optimal temperature for the enzyme, and an enzymatic hydrolysis time of 2-4h can moderately de-methylate the original pectin into low-methoxyl pectin, providing carboxyl sites for the subsequent grafting reaction; The high temperature of 85-95℃ in step S32 can quickly inactivate pectin methylesterase, terminate the enzymatic reaction and avoid over-deesterification; the anhydrous ethanol as a precipitant can make the low methoxyl pectin be analyzed out, and the ethanol washing can remove the residual enzyme solution and impurities to ensure the purity of the product.

[0031] The anhydrous pyridine as a solvent in step S33 can improve the compatibility of the low methoxyl pectin and oleic anhydride, and simultaneously play a catalytic role; the oleic anhydride as a hydrophobic grafting monomer, the mass ratio controlled at 1:(0.2-0.5) can regulate the grafting rate, and ensure that the product has both hydrophilicity and hydrophobicity; the temperature of 60-80℃ can accelerate the reaction rate, and the reaction time of 2-4h can ensure that the esterification reaction of the carboxyl of the low methoxyl pectin and the oleic anhydride is fully carried out; The precipitation after cooling in step S34 can avoid structural changes caused by high temperature, and the anhydrous ethanol precipitation can make the grafted product be analyzed out; the repeated washing for 3-5 times can completely remove the unreacted impurities.

[0032] Application of a dual amphiphilic adsorbent in removing cholesterol from beef tallow.

[0033] Example 1 A dual amphiphilic adsorbent for reducing the cholesterol content of beef tallow, the adsorbent is a core-shell structure microsphere, the core layer is food-grade diatomite modified by a silane coupling agent; the shell layer is a cyclodextrin-pectin composite system, which is composed of a dual amphiphilic cyclodextrin mixture of hydroxypropyl-β-cyclodextrin and octyl-β-cyclodextrin, and an amphiphilic network formed by oleic acid grafted low methoxyl pectin and inulin crosslinked by calcium ions.

[0034] The preparation method of the above-mentioned dual amphiphilic adsorbent, comprising the following steps: S1. refluxing food-grade diatomite and 3% mass fraction of KH-550 silane coupling agent in an ethanol solution at 70℃ for 2.5h, and then washing and drying the product to obtain modified diatomite; S2. adjusting the mass ratio of hydroxypropyl-β-cyclodextrin and octyl-β-cyclodextrin to be 3:1, the mass ratio of the dual amphiphilic cyclodextrin mixture and the oleic acid grafted low methoxyl pectin to be 2:1, and the mass ratio of the oleic acid grafted low methoxyl pectin and inulin to be 5:1, and adjusting the addition amount of CaCl2 to be 2% of the total mass of the shell material, then stirring after dissolving all components in deionized water to form a shell gel solution.

[0035] S3. dispersing the modified diatomite obtained in step S1 in deionized water to obtain a core layer dispersion liquid; S4. under continuous stirring, adding the shell solution prepared in step S2 dropwise into the core layer dispersion liquid of step S3, controlling the mass ratio of modified diatomite and shell material to be 1:3, and stirring at room temperature for 3h until the shell molecules self-assemble on the surface of the diatomite to obtain a core-shell structure adsorbent microsphere.

[0036] Preferably, the preparation method of the octyl-β-cyclodextrin comprises the following steps: S11. Dissolve the β-cyclodextrin in an 8% NaOH solution, control the mass ratio of β-cyclodextrin to NaOH to be 1:0.5, and stir under room temperature and nitrogen protection; S12. Slowly add the 30% brominated octane ethanol solution to the activated solution obtained in step S11, control the molar ratio of brominated octane to glucose units in β-cyclodextrin to be 1:1, and continue to react at 60°C for 4-8h; S13. After the reaction in step S12 is completed, cool the reaction solution to room temperature, neutralize it to neutral with dilute hydrochloric acid, then place it in a dialysis bag and dialyze it with deionized water for 48h; freeze-dry the dialyzed solution at -60°C for 16-24h to obtain octyl-β-cyclodextrin powder with a degree of substitution of 0.2.

[0037] Preferably, the preparation method of the hydroxypropyl-β-cyclodextrin comprises the following steps: S21. Dissolve the β-cyclodextrin in deionized water, add alkali under stirring to adjust the pH of the system to 10 to obtain an alkaline β-cyclodextrin solution; S22. Slowly add the propylene oxide of USP f101929 to the solution obtained in step S21, control the molar ratio of propylene oxide to β-cyclodextrin to be 5:1, and perform hydroxypropylation reaction at 40-60°C for 6h; S23. After the reaction in step S22 is completed, cool the reaction solution to room temperature, neutralize it to neutral with acid, then place it in a dialysis bag and dialyze it with deionized water for 48h; freeze-dry the dialyzed solution to obtain hydroxypropyl-β-cyclodextrin powder with a degree of substitution of 0.5.

[0038] Preferably, the preparation method of the oleic acid grafted low methoxyl pectin comprises the following steps: S31. Disperse the protopectin in a citric acid buffer solution with pH=4 to prepare a dispersion liquid with a mass concentration of 8%, and add pectin methylesterase with a mass of 1% of the protopectin, and enzymatically hydrolyze at 40°C for 2h; S32. Heat the reaction solution obtained in step S31 to 80°C for 10 minutes to inactivate the enzyme, precipitate with anhydrous ethanol after cooling, and wash with ethanol to obtain low methoxyl pectin; S33. Disperse the low methoxyl pectin obtained in step S32 in anhydrous pyridine, add oleic anhydride of 24909-72-6, control the mass ratio of low methoxyl pectin to oleic anhydride to be 1:0.5, and stir at 60°C for 2h; S34. The reaction solution obtained in step S33 is cooled to room temperature, and is slowly poured into anhydrous ethanol under stirring to precipitate, the precipitate is collected and washed with anhydrous ethanol repeatedly for 3 times, and finally dried under vacuum to obtain the oleic acid grafted low methoxyl pectin.

[0039] Use of a dual parent adsorbent for removing cholesterol from butter oil.

[0040] Example 2

[0041] Example 2 differs from Example 1 in that the mass ratio of hydroxypropyl-β-cyclodextrin to octyl-β-cyclodextrin in step S2 is 2:1, the mass ratio of the dual parent cyclodextrin mixture to the oleic acid grafted low methoxyl pectin is 1:1, the mass ratio of the oleic acid grafted low methoxyl pectin to the inulin is 4:1, and the amount of CaCl2 is adjusted to 3% of the total mass of the shell material. After each component is dissolved in deionized water, stirring is performed to form a shell gel solution.

[0042] Example 3

[0043] Example 3 differs from Example 1 in that the mass ratio of hydroxypropyl-β-cyclodextrin to octyl-β-cyclodextrin in step S2 is 5:1, the mass ratio of the dual parent cyclodextrin mixture to the oleic acid grafted low methoxyl pectin is 4:1, the mass ratio of the oleic acid grafted low methoxyl pectin to the inulin is 5:1, and the amount of CaCl2 is adjusted to 1% of the total mass of the shell material. After each component is dissolved in deionized water, stirring is performed to form a shell gel solution.

[0044] Example 4

[0045] Example 4 differs from Example 1 in that the mass ratio of hydroxypropyl-β-cyclodextrin to octyl-β-cyclodextrin in step S2 is 1:1, the mass ratio of the dual parent cyclodextrin mixture to the oleic acid grafted low methoxyl pectin is 0.5:1, the mass ratio of the oleic acid grafted low methoxyl pectin to the inulin is 4:1, and the amount of CaCl2 is adjusted to 2% of the total mass of the shell material. After each component is dissolved in deionized water, stirring is performed to form a shell gel solution.

[0046] Example 5

[0047] Example 5 differs from Example 1 in that in the activation solution obtained in step S12, the brominated octane ethanol solution with a concentration of 50% is slowly added dropwise, and the molar ratio of brominated octane to glucose units in β-cyclodextrin is controlled to 1.5:1 to obtain an octyl-β-cyclodextrin powder with a substitution of 0.3.

[0048] Example 6

[0049] Example 6 differs from Example 1 in that in the activated solution obtained in step S12, a 20% concentration of bromooctane ethanol solution is slowly added dropwise, and the molar ratio of bromooctane to glucose units in the β-cyclodextrin is controlled to be 0.5:1, and then octyl-β-cyclodextrin powder with a substitution degree of 0.1 is obtained.

[0050] Example 7

[0051] Example 7 differs from Example 1 in that in step S22, the molar ratio of propylene oxide to β-cyclodextrin is controlled to be 8:1, and then hydroxypropyl-β-cyclodextrin powder with a substitution degree of 0.8 is obtained.

[0052] Example 8

[0053] Example 8 differs from Example 1 in that in step S22, the molar ratio of propylene oxide to β-cyclodextrin is controlled to be 10:1, and then hydroxypropyl-β-cyclodextrin powder with a substitution degree of 1.0 is obtained.

[0054] Example 9

[0055] Example 9 differs from Example 1 in that in step S33, the mass ratio of low methoxyl pectin to oleic anhydride is controlled to be 1:0.3.

[0056] Comparative Example 1 Comparative Example 1 differs from Example 1 in that in step S2, the mass ratio of hydroxypropyl-β-cyclodextrin to octyl-β-cyclodextrin is 0.5:1, the mass ratio of the amphiphilic cyclodextrin mixture to the oleic acid grafted low methoxyl pectin is 0.1:1, the mass ratio of the oleic acid grafted low methoxyl pectin to the inulin is 1:1, and the amount of CaCl2 added is adjusted to be 0.5% of the total mass of the shell material. After each component is dissolved in deionized water and stirred, a shell gel solution is formed.

[0057] Comparative Example 2 Comparative Example 2 differs from Example 1 in that in step S2, the mass ratio of hydroxypropyl-β-cyclodextrin to octyl-β-cyclodextrin is 10:1, the mass ratio of the amphiphilic cyclodextrin mixture to the oleic acid grafted low methoxyl pectin is 10:1, the mass ratio of the oleic acid grafted low methoxyl pectin to the inulin is 10:1, and the amount of CaCl2 added is adjusted to be 5% of the total mass of the shell material. After each component is dissolved in deionized water and stirred, a shell gel solution is formed.

[0058] Comparative Example 3 Comparative Example 3 differs from Example 1 in that in the activated solution obtained in step S12, a 10% concentration of bromooctane ethanol solution is slowly added dropwise, and the molar ratio of bromooctane to glucose units in the β-cyclodextrin is controlled to be 0.1:1, and then octyl-β-cyclodextrin powder with a substitution degree of 0.05 is obtained.

[0059] Comparative Example 4 Comparative Example 4 differs from Example 1 in that in step S12, the molar ratio of bromooctane to glucose units in β-cyclodextrin is controlled to be 3:1, and the resulting activated solution is slowly added dropwise with a bromooctane concentration of 70% in ethanol, to obtain an octyl-β-cyclodextrin powder with a degree of substitution of 0.6.

[0060] Comparative Example 5 Comparative Example 5 differs from Example 1 in that in step S22, the molar ratio of propylene oxide to β-cyclodextrin is controlled to be 3:1, to obtain a hydroxypropyl-β-cyclodextrin powder with a degree of substitution of 0.2.

[0061] Comparative Example 6 Comparative Example 6 differs from Example 1 in that in step S22, the molar ratio of propylene oxide to β-cyclodextrin is controlled to be 15:1, to obtain a hydroxypropyl-β-cyclodextrin powder with a degree of substitution of 1.5.

[0062] Comparative Example 7 Comparative Example 7 differs from Example 1 in that in step S33, the mass ratio of low methoxyl pectin to oleic anhydride is controlled to be 1:1.

[0063] Comparative Example 8 Comparative Example 8 differs from Example 1 in that in step S33, the mass ratio of low methoxyl pectin to oleic anhydride is controlled to be 1:0.1.

[0064] Comparative Example 9 Comparative Example 9 differs from Example 1 in that only β-cyclodextrin is used.

[0065] Comparative Example 10 Comparative Example 10 differs from Example 1 in that only hydroxypropyl-β-cyclodextrin is used.

[0066] Comparative Example 11 Comparative Example 11 differs from Example 1 in that the pectin used is commercially available CF 120 type pectin, and the low methoxyl pectin is not prepared.

[0067] Comparative Example 12 Comparative Example 12 differs from Example 1 in that steps S33 and S34 of oleic acid grafting are not performed.

[0068] Comparative Example 13 Comparative Example 13 differs from Example 1 in that the core-shell structure is not prepared, and the diatomite core layer structure is not added.

[0069] Comparative Example 14 Comparative Example 14 differs from Example 1 in that only octyl-β-cyclodextrin is used.

[0070] Performance Test: Test Example 1 Removal of Cholesterol: Accurately weigh 4 portions of 50 g of beef tallow into 250 mL beakers. The beakers are numbered 1, 2, 3 and 4 in order of increasing water to oil ratio (0:1, 1.8:1, 3.6:1 and 5.4:1) and placed in a constant temperature water bath at 80°C to melt. No water is added to beaker 1, i.e. water to oil ratio 0:1; 90 mL of distilled water is added to beaker 2, i.e. water to oil ratio 1.8:1; 180 mL of distilled water is added to beaker 3, i.e. water to oil ratio 3.6:1; and 4 beaker water to oil ratio 5.4:1. Then 1.5 g of the adsorbent powder of Example 1 of the present application and Comparative Examples 9 and 11 are added. The beakers are placed in a water bath at 50°C and stirred at 500 rpm / min for 1 h. After stirring, the beakers are centrifuged at 1000 rpm / min for 10 min. The upper layer of oil is scraped off and used for subsequent determination of the cholesterol content of the oil sample.

[0071] As Figure 1 We can see that in order to explore the effect of the adsorbent on the removal of cholesterol in beef tallow systems with different water contents, we used water to oil ratios from low to high (0:1, 1.8:1, 3.6:1 and 5.4:1) for the study. Compared with the cholesterol content of the blank group of beef tallow (210 mg / 100 g), the cholesterol content of the other four groups of beef tallow was reduced to varying degrees. Among them, group 3 (water to oil ratio 3.6:1) had the lowest cholesterol content of 86 mg / 100 g, with a cholesterol removal rate of 89%, group 1 (without water) had the lowest cholesterol removal rate, only 45. Group 2 (water to oil ratio 1.8:1) had an increased cholesterol removal rate (68) but was not the optimal group. This may be that during the removal of cholesterol, water as a polar medium changes the adsorption environment of the complex at the interface between beef tallow and the complex, enhancing the affinity of the complex for cholesterol. At the same time, insufficient water quantity is also one of the reasons for poor cholesterol removal effect. Insufficient water quantity leads to uneven dispersion of the complex, thereby forming local clumps and reducing the effective contact area of the complex and beef tallow. Group 4 (water to oil ratio 5.4:1) had a cholesterol removal rate of 55%. As can be seen from the solubility experiment, the complex is a powder-like substance with good water solubility. Too much water may cause the complex to prefer to disperse in the water phase, thereby reducing the contact between the complex and cholesterol in the oil phase, and thus reducing the removal efficiency. The above experimental results show that a water to oil ratio of 3.6:1 (group 3) can achieve the optimal removal effect. This may be because the appropriate amount of water can not only form a polar adsorption interface to enhance the ability of the complex to adsorb cholesterol, but also ensure the effective dispersion of the complex in the oil phase. Therefore, the appropriate amount of water is more suitable for the complex to fully exert the ability to remove cholesterol.

[0072] and in combinationFigure 2 and Figure 3 It can be seen that the amphiphilic adsorbent prepared in Example 1 has obvious advantages in promoting cholesterol in beef tallow, which is prepared from the amphiphilic cyclodextrin mixture composed of hydroxypropyl-β-cyclodextrin and octyl-β-cyclodextrin, and the amphiphilic network formed by grafting low methoxyl pectin with oleic acid and inulin cross-linked by calcium ions.

[0073] Test Example 2 Preparation of the amphiphilic adsorbent prepared in the present application and its cholesterol removal rate: In a beaker, 1.8915 g of the adsorbent prepared in the examples and comparative examples in the present application and 160 mL of water were placed in a constant temperature magnetic stirrer at 40°C and reacted for 1 h to obtain solution 1. Then 0.3866 g of cholesterol (Chol) was accurately weighed and dissolved in 160 mL of anhydrous ethanol solution to obtain solution 2. The solutions 1 and 2 were mixed uniformly, and reacted at 40°C under stirring for 12 h (to make the reaction complete). After the reaction was completed, centrifugation was performed at a speed of 8000 rpm / min for 15 min. The precipitate was washed with anhydrous ethanol for three times and dried to constant weight. Then 1.8915 g of the adsorbent and 0.3866 g of Chol were simply mixed and ground in a mortar for 5 min to obtain a physical mixture of cholesterol and adsorbent.

[0074] A certain amount (such as 1.0 g) of molten beef tallow was accurately weighed in a centrifuge tube, and a certain amount of adsorbent (such as 0.1 g) was added. After constant temperature oscillation at a certain temperature (such as 60°C) for a certain time (such as 2 h), the adsorbent was centrifuged and separated. The cholesterol content in the beef tallow before and after adsorption was determined by the national standard GB 5009.128-2016 or high performance liquid chromatography (HPLC).

[0075] Cholesterol adsorption rate (%) = [(C0– C1) / C0] × 100%, wherein C0and C1are the cholesterol concentrations in the beef tallow before and after adsorption, respectively.

[0076] Test Example 3 Evaluation of the dispersibility of the adsorbent in beef tallow A certain amount of adsorbent was added to molten beef tallow, and the same amount of adsorbent was stirred at a constant speed for the same time (such as 10 minutes). A small amount of oil sample was taken on a glass slide, observed under an optical microscope, and photographed to count the aggregation and uniformity of the adsorbent particles. Alternatively, a static image analysis method can be used to calculate the dispersion index of the particles.

[0077] Test Example 4 Evaluation of the structural stability of the adsorbent The prepared adsorbent microspheres were placed in a certain volume of beef tallow and treated under simulated process conditions (e.g. mechanical stirring at a certain rotation speed for 30 minutes). After treatment, the adsorbent was separated by a sieve screen and the morphological integrity was observed. Alternatively, the particle size distribution of the microspheres before and after treatment was measured using a laser particle size analyzer, and the structural damage rate was calculated.

[0078] Table 1 Performance comparison of adsorbents of the present application Group Cholesterol adsorption rate (%) Dispersibility evaluation (1-5 points, 5 best) Structural stability (breakage rate) Example 1 94.2 5 <5 Example 2 92.5 4 <5 Example 3 89.1 3 ~8 Example 4 85.7 4 <5 Example 5 93.0 5 <5 Example 6 88.5 4 <5 Example 7 93.8 5 <5 Example 8 92.0 5 <5 Example 9 92.8 5 <5 Comparative Example 1 58.3 2 >20 Comparative Example 2 75.6 3 <5 (but the gel is too hard) Comparative Example 3 65.4 2 <5 Comparative Example 4 71.2 4 ~15 (structure not uniform) Comparative Example 5 70.8 3 <5 Comparative Example 6 82.1 5 <5 Comparative Example 7 79.5 5 (but easy to free oil) ~12 Comparative Example 8 69.9 3 <5 Comparative Example 9 61.5 1 <5 Comparative Example 10 73.8 2 <5 Comparative Example 11 68.2 3 >25 (network unstable) Comparative Example 12 66.7 2 <5 Comparative Example 13 77.0 4 >30 (structure fragile) Comparative Example 9 70.3 1 <5 As can be seen from Table 1, Example 1, as a benchmark, exhibits the best overall performance, with a high adsorption rate of 94.2%, which is due to the water solubility and cavity provided by HP-β-CD, the enhanced oil phase affinity and inclusion capacity of octyl-β-CD, and the hydrophobic anchoring point provided by oleic acid pectin, as well as the stable and robust amphiphilic network provided by the Ca2+-pectin-inulin network. The unmodified β-CD in Comparative Example 9 has the lowest adsorption rate due to its poor oil phase dispersibility, and the ordinary pectin in Comparative Example 11 has the highest structural damage rate (>25%) due to its inability to form a stable cross-linked network. This highlights the reasons for the core-shell structure and amphiphilic design of the present application. Examples 1-4 and Comparative Examples 1-2 show that deviating from the preferred range (1-5:1) of the ratio of cyclodextrins or improper total amount will result in a decrease in adsorption rate. The adsorption rate of Comparative Example 10, which contains only HP-β-CD, is 73.8%, which is much lower than that of Example 1. The comparison of Examples 1, 5, 6, 7, 8 and Comparative Examples 3-6, 7, 8 shows that there is an optimal degree of substitution window for the chemical modification of each component. The excessively low parameter settings of Comparative Examples 3, 5, and 8 cannot effectively improve the solubility or amphiphilicity; the excessively high parameter settings of Comparative Examples 4, 6, and 7 may damage the core function of the parent molecule or result in difficulties in self-assembly and unstable structure. The parameters of Examples 1, 5, 7, and 9 are within this optimal window; the comparison of Comparative Examples 1 and 2 shows that the network formed when the amount of CaCl2 is 1-3% can ensure structural stability without being too dense to affect mass transfer and inclusion. Comparative Example 1 has a high structural damage rate, and Comparative Example 2 is stable but has a low adsorption rate, which may be due to the network being too dense; the high damage rate and low adsorption rate of Comparative Example 13 are in sharp contrast to the stable performance of Example 1 and most other examples, which strongly proves that the diatomite core layer as a rigid skeleton is crucial for maintaining the overall structure of the microspheres and resisting shear forces during processing.

[0079] Test Example 5 Determination of the viscosity of beef tallow An equal amount (0.1 g) of each adsorbent was added to 10 g of molten beef tallow and oscillated at a constant temperature of 60°C for 2 hours, followed by centrifugation at 5000 rpm for 15 minutes, and the supernatant oil was taken for measurement.

[0080] From Figure 4As can be seen from Table 1, after the treatment of Examples 1 and 5, the viscosity of the beef tallow is reduced by 2.1% and 3.2% respectively compared with the blank group. The results show that the adsorbent of the application can effectively remove cholesterol and other lipids, and due to its stable core-shell structure, it is easy to be completely removed, thereby effectively avoiding the influence of residues on the system; the slight reduction in viscosity may be due to the specific adsorption of the adsorbent to cholesterol and other macromolecular lipids, thereby reducing the flow resistance of the oil phase. In contrast, the viscosity of Comparative Example 9 increases by 5.6% due to the agglomeration and residue of unmodified β-cyclodextrin in the oil phase; the viscosity of Comparative Example 11 increases by 25.6% due to the disintegration and fragmentation of the shell structure caused by the use of ordinary pectin, and the dissolution of pectin chains forms a colloidal dispersion system, thereby significantly increasing the viscosity.

[0081] From Figure 5 As can be seen from Table 1, after the treatment of Examples 1 and 5, the viscosity of the beef tallow is reduced by 2.1% and 3.2% respectively compared with the blank group. The results show that the adsorbent of the application can effectively remove cholesterol and other lipids, and due to its stable core-shell structure, it is easy to be completely removed, thereby effectively avoiding the influence of residues on the system; the slight reduction in viscosity may be due to the specific adsorption of the adsorbent to cholesterol and other macromolecular lipids, thereby reducing the flow resistance of the oil phase. In contrast, the viscosity of Comparative Example 9 increases by 5.6% due to the agglomeration and residue of unmodified β-cyclodextrin in the oil phase; the viscosity of Comparative Example 11 increases by 25.6% due to the disintegration and fragmentation of the shell structure caused by the use of ordinary pectin, and the dissolution of pectin chains forms a colloidal dispersion system, thereby significantly increasing the viscosity.

[0082] Obviously, the above examples are merely examples for clarity and do not limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. An amphiphilic adsorbent for reducing the tallow cholesterol content, characterized by: The adsorbent is a core-shell structure microsphere, the core layer of which is food-grade diatomite modified by a silane coupling agent; the shell layer is a cyclodextrin-pectin composite system, which is composed of an amphiphilic cyclodextrin mixture of hydroxypropyl-β-cyclodextrin and octyl-β-cyclodextrin, and an amphiphilic network formed by oleic acid grafted low-methoxyl pectin and inulin crosslinked by calcium ions.

2. The method of claim 1, wherein the amphiphilic adsorbent is prepared by the steps of: The method comprises the following steps: S1. refluxing food-grade diatomite with 1-5% silane coupling agent in an ethanol solution for 2-3 hours, and washing and drying the product to obtain modified diatomite; S2. dissolving hydroxypropyl-β-cyclodextrin, octyl-β-cyclodextrin, oleic acid grafted low-methoxyl pectin and inulin in deionized water in a certain proportion, adding CaCl2 and stirring to form a shell layer gel solution; S3. dispersing the modified diatomite obtained in step S1 in deionized water to obtain a core layer dispersion liquid; S4. under continuous stirring, adding the shell layer solution prepared in step S2 dropwise into the core layer dispersion liquid in step S3, controlling the mass ratio of modified diatomite to shell layer material to be 1:(2-5), and stirring at room temperature for 2-6 hours until the shell layer molecules self-assemble on the surface of the diatomite to obtain a core-shell structure adsorbent microsphere.

3. The method of claim 2, wherein: In step S2, the mass ratio of hydroxypropyl-β-cyclodextrin to octyl-β-cyclodextrin is (1-5):1; and / or, The mass ratio of the amphiphilic cyclodextrin mixture to the oleic acid grafted low-methoxyl pectin is (0.2-4):1 and / or, The mass ratio of the oleic acid grafted low-methoxyl pectin to the inulin is (4-5):

1.

4. The method of claim 2, wherein: In step S1, the silane coupling agent is at least one of KH-550 and KH-560; and / or, The reflux temperature is 70-85°C.

5. The method of claim 2, wherein: In step S2, the amount of CaCl2 added is 1-3% of the total mass of the shell layer material.

6. The method of claim 2, wherein: The preparation method of the octyl-β-cyclodextrin comprises the following steps: S11. dissolving β-cyclodextrin in a 5%-10% NaOH solution, controlling the mass ratio of β-cyclodextrin to NaOH to be 1:(0.5-1), and stirring at room temperature under nitrogen protection for activation; S12. slowly adding a 20%-50% brominated octane ethanol solution to the activated solution obtained in step S11, controlling the molar ratio of brominated octane to glucose units in β-cyclodextrin to be (0.5-1.5):1, and continuously reacting at 60-75°C for 4-8 hours; S13. after the reaction in step S12 is completed, the reaction solution is cooled to room temperature, neutralized to neutral with dilute hydrochloric acid, then placed in a dialysis bag and dialyzed with deionized water for 48-72 hours; the dialyzed solution is freeze-dried at -50°C to -70°C for 16-24 hours to obtain an octyl-β-cyclodextrin powder with a degree of substitution of 0.1-0.

3.

7. The method of claim 2, wherein the amphiphilic adsorbent is prepared by the steps of: The preparation method of the hydroxypropyl-β-cyclodextrin comprises the following steps: S21. dissolving β-cyclodextrin in deionized water, adding alkali under stirring to adjust the pH of the system to 9-11 to obtain an alkaline β-cyclodextrin solution; S22. Slowly add propylene oxide to the solution obtained in step S21, control the molar ratio of propylene oxide to β-cyclodextrin to be (5-10):1, and carry out the hydroxypropylation reaction at 40-60°C for 6-12 h; S23. After the reaction in step S22 is completed, cool the reaction solution to room temperature, neutralize it to neutral with an acid solution, and then place it in a dialysis bag for purification by dialysis against deionized water for 48-72 h; freeze-dry the solution after dialysis to obtain hydroxypropyl-β-cyclodextrin powder with a degree of substitution of 0.5-1.

0.

8. The method of claim 2, wherein: The preparation method of the oleic acid grafted low-methoxyl pectin comprises the following steps: S31. Disperse the protopectin in a citric acid buffer solution with a pH of 3.5-4.5, prepare a dispersion liquid with a mass concentration of 5%-10%, and add pectin methylesterase with a mass of 0.5%-2% of the protopectin, and carry out enzymatic hydrolysis at 40-50°C for 2-4 h; S32. Heat the reaction solution obtained in step S31 to 85-95°C for 10-20 min to inactivate the enzyme, cool it, precipitate it with anhydrous ethanol, and wash it with ethanol to obtain low-methoxyl pectin; S33. Disperse the low-methoxyl pectin obtained in step S32 in anhydrous pyridine, add oleic anhydride, control the mass ratio of low-methoxyl pectin to oleic anhydride to be 1:(0.2-0.5), and carry out stirring reaction at 60-80°C for 2-4 h; S34. Cool the reaction solution obtained in step S33 to room temperature, slowly pour it into anhydrous ethanol under stirring for precipitation, collect the precipitate, and wash it repeatedly with anhydrous ethanol for 3-5 times, and finally vacuum-dry it to obtain oleic acid grafted low-methoxyl pectin.

9. Use of the amphiphilic adsorbent according to claim 1 for removing cholesterol from butter oil.

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