A functional powder grease and a method for preparing the same

Abstract

The application belongs to the technical field of oil processing, and particularly relates to a functional powder oil and a preparation method thereof. In the application, the pH of a complex emulsion formed by sodium caseinate and polysaccharide is adjusted to 3.0-6.0 by a pH driving method to serve as an aqueous phase, and the particle size of the complex emulsion is controlled to 300-500 nm by high-pressure homogenization, so that the complex emulsion is better adsorbed on the oil-water interface. Meanwhile, vegetable oil is used as an oil phase, and a monoglyceride surfactant, a gel factor and a fat-soluble bioactive nutritional ingredient are added in the oil phase. Then, the aqueous phase and the oil phase are mixed, and the complex particles formed by sodium caseinate and polysaccharide and the monoglyceride surfactant in the oil phase are used as wall materials to encapsulate the fat-soluble bioactive nutritional ingredient, so that the functional powder oil is obtained. The powder oil prepared in the application has an oil content of 92.7%, good stability and low-temperature cold solubility, and the retention rate is still maintained at more than 70% after 50 days of storage at room temperature.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil processing, and particularly relates to a functional powder oil and a preparation method thereof. BACKGROUND

[0002] Fat-soluble bioactive nutrients, such as beta-carotene, curcumin, lutein, etc., have positive effects on antioxidation, anticancer, anti-aging activity, and prevention of various chronic diseases, etc. However, these molecules have poor water solubility and chemical stability, are sensitive to pH value, oxygen or salt ions, and are easily degraded by the environment and the digestive system, thus having a low bioavailability.

[0003] Powder oil is a granular and uniform powder product formed by embedding oil with appropriate wall materials using microencapsulation technology. On the basis of maintaining the inherent properties of oil, powder oil also has the characteristics of relieving oxidation of oil droplets, prolonging shelf life, masking bad flavor, excellent processing properties, convenient storage and transportation, etc. Therefore, after the fat-soluble bioactive substance is microencapsulated into functional powder oil, the stability of the active substance can be improved, and the powder oil can also be used as a food additive or a nutritional supplement to improve the taste, flavor and functional properties of food.

[0004] However, the functional powder oil prepared by using conventional emulsifiers generally has high surface oil content, low oil loading, poor low-temperature cold solubility, and poor stability of the loaded active substance, etc. This is mainly because the conventional wall materials and oil phase microstructure cannot meet the needs of the preparation of functional powder oil. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a functional powder oil and a preparation method thereof.

[0006] The functional powder oil prepared in the present application has a high embedding rate of 92.7%, and the retention rate of the embedded fat-soluble bioactive nutrient component is still maintained at more than 70% after 50 days of storage at room temperature. The low-temperature cold solubility of the powder oil is good, and a uniform reconstituted emulsion system can be formed at room temperature.

[0007] In the present application, first, the sodium caseinate and polysaccharide are electrostatically recombined by pH driving method, the pH of the complex emulsion formed by the sodium caseinate and polysaccharide is adjusted to 3.0-6.0 as the water phase, and the particle size of the complex particles formed by the sodium caseinate and polysaccharide is controlled to 300-500 nm by high pressure homogenization, so that it is better adsorbed on the oil-water interface. At the same time, vegetable oil is used as the oil phase and monoglyceride surfactant, gelling factor and fat-soluble bioactive nutritional ingredients are added in the oil phase, then the water phase is mixed with the oil phase added with monoglyceride surfactant, gelling factor and fat-soluble bioactive nutritional ingredients, the complex particles formed by protein and polysaccharide and monoglyceride surfactant are used as wall materials to encapsulate fat-soluble bioactive nutritional ingredients, so that the functional powder oil is obtained.

[0008] In the preparation method of the above functional powder oil:

[0009] The polysaccharide is selected from any one of carrageenan, high-methoxyl pectin and low-methoxyl pectin;

[0010] The vegetable oil is selected from any one of soybean oil, sunflower seed oil, olive oil, rapeseed oil and corn oil;

[0011] The monoglyceride surfactant is selected from any one of lauric acid monoglyceride and palmitic acid monoglyceride;

[0012] The gelling factor is selected from at least one of beeswax, rice bran wax and palm wax;

[0013] The fat-soluble bioactive nutritional ingredient is selected from any one of beta-carotene, curcumin and lutein.

[0014] Preferably, the polysaccharide is carrageenan.

[0015] Preferably, the vegetable oil is corn oil.

[0016] The preparation method of the functional powder oil provided by the present application comprises the following steps:

[0017] (1) Preparation of the complex emulsion formed by sodium caseinate and polysaccharide

[0018] Sodium caseinate and polysaccharide are dissolved in deionized water respectively to prepare a stock solution of sodium caseinate and a stock solution of polysaccharide, and then the stock solutions are stirred thoroughly and left overnight. Then the stock solution of sodium caseinate and the stock solution of polysaccharide are mixed in a weight ratio of 1-3:2-1, heated at 80-85°C for 20-30 min, and then cooled to room temperature. The pH of the mixture of the complex of sodium caseinate and polysaccharide is adjusted to 3.0-6.0 by pH driving method. Then the prepared complex mixture is homogenized under high pressure microjet to control the particle size of the complex to 300-500 nm, and a complex emulsion of sodium caseinate and polysaccharide is obtained.

[0019] (2) Preparation of oil phase containing fat-soluble bioactive nutritional ingredients

[0020] The oil phase containing fat-soluble bioactive nutritional ingredients is prepared by adding monoglyceride surfactant and gel factor to vegetable oil, and then adding fat-soluble bioactive nutritional ingredients, and then heating and stirring and then ultrasonic treatment.

[0021] (3) Preparation of emulsion system loaded with fat-soluble bioactive nutritional ingredients

[0022] The complex emulsion of sodium caseinate and polysaccharide prepared in (1) and the oil phase containing fat-soluble bioactive nutritional ingredients prepared in (2) are mixed in a weight ratio of 1-10:1, and then high-speed shearing and ultrasonic treatment are performed to prepare an emulsion system loaded with fat-soluble bioactive nutritional ingredients.

[0023] (4) Preparation of functional powder oil

[0024] The emulsion system loaded with fat-soluble bioactive nutritional ingredients in (3) is subjected to spray drying treatment to obtain functional powder oil rich in fat-soluble bioactive nutritional ingredients.

[0025] In the above preparation method, preferably, in (1), the complex mixture is homogenized 3-4 times under high pressure microjet of 6000-10000 psi.

[0026] Preferably, in (1), the mass fraction of the complex emulsion of sodium caseinate and polysaccharide is 1-3%.

[0027] Preferably, in (2), when the monoglyceride surfactant is lauric acid monoglyceride, the amount of the monoglyceride surfactant added is 5-20% of the total weight of the oil phase; when the monoglyceride surfactant is palmitic acid monoglyceride, the amount of the monoglyceride surfactant added is 1-5% of the total weight of the oil phase, the amount of the gel factor added is 2-6% of the total weight of the oil phase, and the amount of the fat-soluble bioactive nutritional ingredients is 0.5-2% of the total weight of the oil phase.

[0028] Preferably, in (2), the heating temperature is in the range of 60-80°C.

[0029] Preferably, in (3), the complex emulsion of sodium caseinate and polysaccharide is mixed with the oil phase containing the fat-soluble bioactive nutrient ingredient at a weight ratio of 9:1.

[0030] Preferably, the high-speed shearing rate in (3) is 12000 rpm, the ultrasonic frequency is 20-25 kHz, the ultrasonic power is 360-600 W, the ultrasonic treatment time is 3-9 min, the working time and the intermittent time are both 5 s, and the sample is placed in an ice water bath during the ultrasonic process to control the ultrasonic temperature.

[0031] Further, the application provides a preparation method of the functional powder oil, which comprises the following steps:

[0032] (1) Preparation of the complex emulsion of sodium caseinate and polysaccharide

[0033] Sodium caseinate and carrageenan are respectively dissolved in deionized water to prepare the stock solutions of sodium caseinate and carrageenan, which are then fully stirred and placed overnight, then the stock solution of sodium caseinate is mixed with the stock solution of carrageenan at a weight ratio of 2:1, heated at 80-85 ℃ for 20-30 min, and then cooled to room temperature, the pH of the mixed solution of the complex of sodium caseinate and polysaccharide is adjusted to 3.0-6.0 by the pH driving method, then the prepared complex mixed solution is homogenized at a high pressure microfluidizer 6000-10000 psi for 3-4 times to control the particle size of the complex to be 300-500 nm, and the complex emulsion of sodium caseinate and carrageenan is obtained.

[0034] (2) Preparation of the oil phase containing β-carotene

[0035] The monoglyceride surfactant and the gel factor are added to the corn oil, and then β-carotene is added, which is heated and stirred at 60-80 ℃ and then treated by ultrasonic wave to obtain the oil phase containing β-carotene;

[0036] When the monoglyceride surfactant is lauric acid monoglyceride, the addition amount is 5-20% of the total weight of the oil phase; when the monoglyceride surfactant is palmitic acid monoglyceride, the addition amount is 1-5% of the total weight of the oil phase, the addition amount of the gel factor is 2-6% of the total weight of the oil phase, and the β-carotene is 0.5% of the total weight of the oil phase.

[0037] (3) Preparation of the β-carotene-loaded emulsion system

[0038] The complex emulsion of sodium caseinate and carrageenan prepared in (1) is mixed with the oil phase containing β-carotene prepared in (2) at a weight ratio of 1-:10:1, and then treated by high-speed shearing and ultrasonic wave to prepare the β-carotene-loaded emulsion system.

[0039] (4) Preparation of functional powder oil

[0040] The emulsion system loaded with beta-carotene in (3) is prepared into a functional powder oil rich in beta-carotene through spray drying.

[0041] The present application has the following advantages:

[0042] (1) Excellent low-temperature cold solubility

[0043] The functional powder oil provided by the present application has an oil content as high as 92.7%, and is a uniform re-dissolved emulsion at room temperature, and has good low-temperature cold solubility.

[0044] (2) Good stability of the loaded active substance

[0045] Based on the complexing property of sodium caseinate and polysaccharide, the present application makes sodium caseinate and polysaccharide undergo electrostatic complexation through a pH-driven method, and controls the particle size of the complex particles formed by sodium caseinate and polysaccharide by means of high-pressure homogenization, so that the particle size range is 300-500 nm. The complex emulsion in this particle size range can better adsorb to the oil-water interface;

[0046] Meanwhile, the addition of monoglyceride surfactant in the oil phase of the present application can also effectively promote the adsorption of the complex at the interface. The crystallizability of the monoglyceride surfactant on the interface is used to construct a protective shell structure. The above-mentioned complex and monoglyceride surfactant are used as wall materials in cooperation, realizing efficient encapsulation of liposoluble bioactive nutritional ingredients such as beta-carotene, curcumin, and lutein, and effectively enhancing the stability of the powder oil and the loaded active substance. For example, in the simulation of gastrointestinal digestion test, the release rate of beta-carotene encapsulated in the powder oil in the stomach is less than 20%, and the release rate in the intestine is more than 70%.

[0047] (3) Improved emulsifying capacity and oil embedding rate of the product

[0048] The gel factors such as beeswax, rice bran wax, and palm wax added in the preparation process of the powder oil of the present application effectively improve the emulsifying capacity, and reduce the surface oil content of the powder oil by structuring the oil phase, thereby improving the oil embedding rate of the powder oil.

[0049] And, the present application adopts ultrasonic treatment technology, utilizes its cavitation effect and high intensity shearing effect to disperse the crystal of gel factor such as beeswax, rice bran wax, palm wax, etc., and the prepared emulsion system has relatively narrow size distribution, which is beneficial to the improvement of the stability of powder oil and active substance loaded in the powder oil in later period, for example, the retention rate of the powder oil embedding β-carotene prepared in the present application is still kept above 70% after 50 days of storage at room temperature. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The release of β-carotene of the powder oil embedding β-carotene prepared by different methods in examples 4-6 of the present application in the process of simulating the digestion of stomach and intestine;

[0051] Figure 2 The storage stability of β-carotene in the powder oil embedding β-carotene prepared by different methods in examples 1-6 of the present application;

[0052] Figure 3 The electron scanning diagram of the powder oil prepared in example 7 of the present application. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the present application, the present application will be further described in conjunction with specific embodiments.

[0054] The low methoxyl pectin used in the present application has a methoxyl content less than 40%, which is self-made in the laboratory.

[0055] The high methoxyl pectin used in the present application has a methoxyl content greater than 70%, which is purchased from the company of McIlvaine Reagent.

[0056] Example 1

[0057] (1) Preparation of the complex emulsion of sodium caseinate and polysaccharide

[0058] Sodium caseinate and low methoxyl pectin were dissolved in deionized water to prepare a 3% sodium caseinate stock solution and a 2% low methoxyl pectin stock solution, respectively, and after fully stirring, they were placed overnight, then the sodium caseinate stock solution and the low methoxyl pectin stock solution were mixed in a weight ratio of 2:1, heated at 85°C for 30 min and then cooled to room temperature, the pH of the complex mixture of sodium caseinate and low methoxyl pectin was adjusted to 5.0, and then the prepared complex mixture was homogenized at high pressure microfluidization 8000 psi for 3 times to obtain the complex emulsion of sodium caseinate and low methoxyl pectin;

[0059] (2) Preparation of the oil phase containing β-carotene

[0060] In the corn oil, lauric acid monoglyceride and β-carotene are added, heated and stirred at 60°C, and then treated by ultrasonic wave to ensure complete dissolution of the oil-soluble substances, thus obtaining an oil phase containing β-carotene;

[0061] In the formula, the amount of lauric acid monoglyceride added accounts for 10% of the total weight of the oil phase, and the amount of β-carotene accounts for 0.5% of the total weight of the oil phase.

[0062] (3) Preparation of β-carotene-loaded emulsion system

[0063] The β-carotene-loaded emulsion system is prepared by mixing the sodium caseinate-low methoxyl pectin complex emulsion prepared in (1) with the oil phase containing β-carotene prepared in (2) at a weight ratio of 9:1, and then high-speed shearing and ultrasonic treatment at 12000 rpm. The ultrasonic treatment conditions are as follows: ultrasonic frequency 20 kHz, ultrasonic power 500 W, ultrasonic treatment time 3 min, working time and intermittent time both 5 s, and the sample is placed in an ice water bath during ultrasonic treatment to control the ultrasonic temperature.

[0064] (4) Preparation of functional powder oil

[0065] The β-carotene-loaded emulsion system prepared in (3) is treated by spray drying to prepare a functional powder oil rich in β-carotene (NaCas-LMP-MG).

[0066] Example 2

[0067] Different from Example 1, only the polysaccharide used in step (1) is high methoxyl pectin, and the rest is the same as Example 1. The prepared powder oil is represented by NaCas-HMP-MG.

[0068] Example 3

[0069] Different from Example 1, only the polysaccharide used in step (1) is carrageenan, and the pH of the sodium caseinate-carrageenan complex mixture is adjusted to 6.0. The prepared powder oil is represented by NaCas-Carrageenan-MG.

[0070] Example 4

[0071] Different from Example 1, no monoglyceride surfactant is added in the preparation of the oil phase in (2). The prepared powder oil is represented by NaCas-LMP.

[0072] Example 5

[0073] Different from Example 2, no monoglyceride surfactant is added in the preparation of the oil phase in (2). The prepared powder oil is represented by NaCas-HMP.

[0074] Example 6

[0075] Different from example 3, in the preparation process of the oil phase in (2), no monoglyceride surfactant is added, and the prepared powder oil is represented by NaCas-Carrageenan.

[0076] Example 7

[0077] Different from example 3, the gel factor beeswax is added in the oil phase in step (2), and the addition amount of the beeswax accounts for 6% of the total weight of the oil phase, and the prepared powder oil is represented by NaCas-Carrageenan-MG-gel factor.

[0078] In addition, in the preparation process of the powder oil, the particle size of the prepared composite emulsion particles is detected by using a particle size instrument, and the detection result shows that the particle size of the particles in the prepared composite emulsion is in the range of 400-500 nm, and the particle size uniformity is strong.

[0079] Example 8

[0080] Different from example 1, in step (1), the weight ratio of the sodium caseinate solution to the polysaccharide solution is respectively set as 4:1, 3:1 and 2:1, and the stability of the prepared composite emulsion in different proportions of different types of polysaccharides is shown in Table 1.

[0081] Table 1 Stability index of composite emulsion obtained by different polysaccharides and proportions

[0082]

[0083] The higher the stability index in the above table, the better the stability of the emulsion.

[0084] From the data in Table 1, it can be seen that the stability index of the composite emulsion obtained by compounding carrageenan and sodium caseinate is significantly higher than that of low methoxyl pectin and high methoxyl pectin compounded with sodium caseinate, which shows that the composite emulsion formed by compounding carrageenan and sodium caseinate can obtain better stability.

[0085] In addition, the results show that as the content of polysaccharide gradually increases, the stability of the composite emulsion also gradually increases, especially when the weight ratio of the sodium caseinate solution to the carrageenan solution is 2:1, the stability index of the composite emulsion is the highest, which is 1.442, therefore, in the present application, the weight ratio of the sodium caseinate solution to the polysaccharide solution is 2:1 for compounding, preferably, the polysaccharide is carrageenan.

[0086] Example 9

[0087] Different from example 7, palmitic acid monoglyceride is added to replace lauric acid monoglyceride, and the amount of palmitic acid monoglyceride accounts for 5% of the total weight of the oil phase. It is found through experiments that the functions and properties of the prepared powder oil product are almost the same as those of example 7.

[0088] Example 10

[0089] Different from example 7, the fat-soluble bioactive nutritional ingredient is lutein, and the gel factor is palm wax, and the rest is the same as example 7.

[0090] The powder oil containing lutein prepared by the same method as example 7 has an oil content of up to 90%, and the retention rate of the embedded fat-soluble bioactive nutritional ingredient is still maintained at more than 72% after 50 days of storage at room temperature.

[0091] Example 11

[0092] Different from example 7, in step S1, the compound emulsion is prepared by only one homogenization, and the homogenization rate is 5000 psi. The other preparation operations of the powder oil are the same as those of example 7.

[0093] In this embodiment, the particle size of the prepared compound emulsion is measured by a particle size analyzer. The results show that the particle size of the compound is more than 800 nm. The stability of the finally prepared powder oil is far lower than that of the powder oil in example 7. The possible reason is that the particle size of the compound emulsion in example 7 is smaller, the uniformity is higher, the adsorption of the compound particles on the interface is relatively more, the particle size of the formed emulsion is also more uniform, and it is beneficial to the improvement of the stability of the emulsion.

[0094] Test example 1

[0095] The release rate of β-carotene in the powder oil under the simulated gastric and intestinal digestion conditions is measured.

[0096] The present inventors have found that the addition of monoglyceride surfactants, gel factors and other components has little effect on the digestion effect of the powder oil in the body. Therefore, in this test example, only the digestion of the powder oil prepared without adding monoglyceride surfactants, gel factors and other components (the powder oils of examples 4-6) is detected.

[0097] The powder oils prepared in examples 4-6 are reconstituted in deionized water, and then simulated gastric and intestinal digestion is carried out. The prepared simulated gastric and intestinal juice is digested for 2 h, all reactions are carried out at 37℃, and at the set time point, an equal amount of digestion liquid is taken out, the reaction is terminated, and the amount of released β-carotene in the digestion liquid is measured. At the same time, a sodium caseinate (NaCas) emulsion system without adding polysaccharides is used as a control.

[0098] The cumulative release rate of β-carotene was calculated according to the following formula:

[0099] Cumulative release rate (%) = C released in the digestion solution / C initial emulsion β-carotene x 100%.

[0100] The release of β-carotene in the powder oil prepared in Examples 4-6 during the simulated gastric and intestinal digestion is shown in Table 2 and Figure 1. Figure 1

[0101] Table 2 Cumulative release rate (%) of β-carotene in the powder oil during the simulated gastric and intestinal digestion

[0102]

[0103] Figure 1 Cumulative release rate (%) of β-carotene in the powder oil during the simulated gastric and intestinal digestion Figure 1 It is shown that the release rate of β-carotene in the emulsion of the complex of different polysaccharides and sodium caseinate is less than 20% in the stomach, which is significantly lower than that of the control group of sodium caseinate (NaCas) emulsion system. In the simulated intestinal digestion, the release rate of β-carotene in the emulsion of the complex of different polysaccharides and sodium caseinate is significantly higher than that of the control group of NaCas emulsion system. It can be seen that the release of β-carotene in the simulated gastric juice is effectively controlled, and β-carotene can be continuously and efficiently released in the subsequent intestinal juice.

[0104] The reason for this phenomenon is that, on the one hand, the electrostatic interaction between polysaccharides and NaCas is enhanced due to the positive charge of NaCas at low pH in the gastric juice, forming a more compact complex, thereby inhibiting the decomposition of protease and further inhibiting the degradation of β-carotene inside the emulsion; on the other hand, polysaccharides act as a barrier to protect the enzymatic degradation of proteins under gastric conditions, thereby ensuring the sustained release of encapsulated active substances in the intestine. In other words, the complex system of sodium caseinate and polysaccharides is more conducive to the sustained release of β-carotene encapsulated therein in the body.

[0105] In addition, the complexing effect of carrageenan and sodium caseinate is the best, followed by the complexing effect of low methoxyl pectin and sodium caseinate, and the sustained release effect of the powder oil prepared by the complex of high methoxyl pectin and sodium caseinate is the worst.

[0106] This may be because carrageenan has a larger net charge, and the molecular attraction of the NH 3+ group of proteins to the OSO 3- group of carrageenan is stronger than the CO 2- group of pectin. Therefore, the emulsion system prepared by the NaCas-carrageenan complex system is more sensitive to pH regulation and is more easily aggregated to form a gel state under gastric acid conditions, which is conducive to the protection of β-carotene.​

[0107] In addition, low methoxyl pectin and high methoxyl pectin, although both are pectin, the low methoxyl pectin has a greater charge density on the surface of the molecule than the high methoxyl pectin, and has a stronger electrostatic interaction with sodium caseinate. Therefore, the release rate of the prepared powder oil in gastric juice is lower than that of the high methoxyl pectin-sodium caseinate complex, and the release rate in intestinal juice is higher.

[0108] Test Example 2

[0109] Particle size and potential of the powder oil complex emulsion were measured.

[0110] The particle size and potential of the powder oil prepared in Examples 1-6 were measured.

[0111] 100 mg of the powder oil sample prepared in Examples 1-6 was weighed into 10 mL of water, and stirred by hand for 30 s. The color of the reconstituted emulsion was observed for uniformity, and the particle size and potential of the powder oil were measured. The particle size and potential of the powder oil prepared by different methods in Examples 1-6 are shown in Table 3.

[0112] Table 3 Particle size and potential of the powder oil reconstituted emulsion

[0113] Example Sample Particle size (pm) Zeta potential (mV) Example 1 NaCas-LMP-MG 1.203±0.009 -52.23±0.69 Example 2 NaCas-HMP-MG 1.067±0.017 -53.97±0.95 Example 3 NaCas-Carrageenan-MG 0.967±0.002 -54.97±0.95 Example 4 NaCas-LMP 2.408±0.029 -47.27±0.63 Example 5 NaCas-HMP 2.227±0.012 -48.97±0.95 Example 6 NaCas-Carrageenan 2.012±0.015 -48.97±0.95

[0114] The data in Table 3 shows that the particle size of the emulsion after reconstitution of the powder oil prepared in Examples 1-3 is 0.967-1.203 μm, and the potential is -54.97 to -52.23 mV. The particle size of the emulsion after reconstitution of the powder oil prepared in Comparative Examples 1-3 is 2.012-2.408 μm, and the potential is -48.97 to -47.27 mV. It can be seen that, compared with the powder oil without added monoglyceride, the particle size of the emulsion after reconstitution of the powder oil with added monoglyceride surfactant is much smaller than that of Examples 4-6, and the ζ-potential of the emulsion is greater than that of the control group. This indicates that the complex and monoglyceride can synergistically affect the interfacial behavior of the emulsion to enhance the stability of the system and the bioactive substances loaded therein.

[0115] In addition, the oil embedding rate of the powder oil prepared by different methods is shown in Table 4.

[0116] Table 4 Oil embedding rate of the powder oil

[0117]

[0118]

[0119] As can be seen from the data in Table 4, the addition of monoglycerides and gelling agents can effectively improve the oil encapsulation rate of oil powder and reduce the surface oil content, thus making it more conducive to the oxidative stability of oil powder and its loaded bioactive substances.

[0120] Experimental Example 3

[0121] Determination of the storage stability of powdered oils.

[0122] The powdered oil samples prepared in Examples 3 and 6-7 were stored at room temperature of 25°C. Samples were taken at different time points, and the retention rate of β-carotene during storage at different temperatures was calculated according to the following formula. The storage stability of β-carotene powder was used as a control.

[0123] Retention rate (%) = (C n / C0)×100%.

[0124] In the above formula, C0 represents the β-carotene content in the initial powdered oil, and C... n The content of β-carotene in the powdered oil on day n.

[0125] The changes in the retention rate of β-carotene in the oil powder with prolonged storage time are shown in Table 5 and Appendix. Figure 2 As shown.

[0126] Table 5. Retention rate (%) of β-carotene in oil powder at different times.

[0127] Powdered oil type 7d 14d 21d 30d 50d NaCas-Carrageenan-MG 94.22％ 90.9％ 81.8％ 78.43％ 72.45％ NaCas-Carrageenan 93.69％ 88.38％ 80.42％ 76.41％ 60.32％ NaCas-Carrageenan-MG-gelling factor 85.93％ 82.38％ 77.27％ 69.86％ 55.01％

[0128] from Figure 2 The results show that the retention rate of β-carotene in the powdered oil prepared using only the sodium caseinate-carrageenan complex decreased from the initial 85% to 55% after 50 days of storage. When monoglycerides were added to the sodium caseinate-carrageenan complex, the retention rate of β-carotene in the powdered oil decreased from the initial 92.7% to 60% after 50 days of storage. Furthermore, when a gelling agent was added to the powdered oil system, the retention rate of β-carotene in the powdered oil remained above 70% after 50 days of storage.

[0129] It is evident that the addition of monoglycerides and gelling agents can effectively improve the stability of bioactive substances when preparing functional oil powder loaded with bioactive substances. This is related to factors such as the formation of a shell structure by crystallization at the oil-water interface by monoglycerides and the structuring of the oil phase by gelling agents. This also proves that monoglycerides and gelling agents can not only improve the oil encapsulation rate of powdered oils but also improve their physical stability.

[0130] Test Example 4

[0131] The surface microstructure of the oil powder prepared in Example 7 was observed by scanning electron microscope, as shown in Figure 6. It can be seen that the powder oil prepared by spray drying presents a regular spherical structure of different sizes, and no obvious cracks or gaps can be observed on the surface of the wall material of the powder oil, which further confirms that the powder oil prepared by the present application has a relatively complete structure and can well embed oil and the bioactive substances loaded therein. Figure 3 The surface microstructure of the oil powder prepared in Example 7 was observed by scanning electron microscope, as shown in Figure 6. It can be seen that the powder oil prepared by spray drying presents a regular spherical structure of different sizes, and no obvious cracks or gaps can be observed on the surface of the wall material of the powder oil, which further confirms that the powder oil prepared by the present application has a relatively complete structure and can well embed oil and the bioactive substances loaded therein.

Claims

1. A method for producing a functional powder oil, characterized by, The functional powder grease is prepared by the following steps: (1) Preparation of a complex emulsion of sodium caseinate and polysaccharide Sodium caseinate and carrageenan are respectively dissolved in deionized water to prepare a 3% sodium caseinate stock solution and a 2% carrageenan stock solution by mass fraction. After being fully stirred and placed overnight, the sodium caseinate stock solution and the carrageenan stock solution are mixed at a weight ratio of 2:1, heated at 80-85°C for 20-30 min, and then cooled to room temperature. The pH of the complex mixture of sodium caseinate and carrageenan is adjusted to 3.0-6.0 by a pH driving method, and then the prepared complex mixture is homogenized at a high pressure of 6000-10000 psi for 3-4 times to obtain a complex emulsion of sodium caseinate and carrageenan with a particle size of 300-500 nm; (2) Preparation of an oil phase containing β-carotene A monoglyceride surfactant and a gel factor are added to corn oil, and then β-carotene is added. After being heated and stirred at 60-80°C and then treated by ultrasonic waves, an oil phase containing β-carotene is obtained. When the monoglyceride surfactant is lauric acid monoglyceride, the amount of the monoglyceride surfactant added is 5-20% of the total weight of the oil phase. When the monoglyceride surfactant is palmitic acid monoglyceride, the amount of the monoglyceride surfactant added is 1-5% of the total weight of the oil phase, the amount of the gel factor added is 2-6% of the total weight of the oil phase, and the amount of β-carotene is 0.5% of the total weight of the oil phase. The gel factor is selected from at least one of beeswax, rice bran wax, and palm wax; (3) Preparation of a β-carotene-loaded emulsion system The complex emulsion of sodium caseinate and carrageenan prepared in (1) and the oil phase containing β-carotene prepared in (2) are mixed at a weight ratio of 1-10:1, and then treated by high-speed shearing and ultrasonic waves to prepare a β-carotene-loaded emulsion system; (4) Preparation of a functional powder grease The β-carotene-loaded emulsion system prepared in (3) is treated by spray drying to prepare a functional powder grease rich in β-carotene.

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