Preparation method of delivery system for fat-soluble nutrients

Abstract

The present invention discloses a method for preparing a delivery system for fat-soluble nutrients, relating to the field of food technology. The method comprises the following steps: dissolving rice bran polysaccharide and surfactant in water, adjusting the pH to 7-11, and freeze-drying to obtain a freeze-dried product; subjecting the freeze-dried product to a Maillard reaction under heating conditions to obtain a surfactant-rice bran polysaccharide conjugate; dissolving the fat-soluble nutrient in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase and stirring to obtain a crude emulsion; and homogenizing the crude emulsion to obtain a delivery system for the fat-soluble nutrient. The Maillard reaction-based surfactant-rice bran polysaccharide conjugate has excellent emulsifying ability, high surface activity, and stable emulsifying activity, antioxidant properties, pH value, temperature, and ionic strength stability, and has great potential in constructing fat-soluble nutrient delivery systems.

Description

Technical Field

[0001] The present invention relates to the field of food technology, and in particular to a method for preparing a fat-soluble nutrient delivery system. Background Art

[0002] Fat-soluble nutrients in the diet have an important impact on human health, but due to their high hydrophobicity, low water solubility, poor processing stability, high permeability and other factors, their solubility in the gastrointestinal tract and oral bioavailability are low, and their application in the food field is subject to certain limitations. Summary of the Invention

[0003] The main purpose of the present invention is to propose a preparation method of a fat-soluble nutrient delivery system, aiming to prepare a green nanoemulsion delivery system of fat-soluble nutrients with pH value, ionic strength and thermal stability.

[0004] To achieve the above objectives, the present invention provides a method for preparing a fat-soluble nutrient delivery system, comprising the following steps:

[0005] S10, dissolving rice bran polysaccharide and surfactin in water, adjusting the pH to 7-11, and freeze-drying to obtain a freeze-dried product;

[0006] S20, subjecting the freeze-dried product to a Maillard reaction under heating conditions to obtain a surfactin-rice bran polysaccharide conjugate;

[0007] S30, dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase and stirring to obtain a crude emulsion;

[0008] S40, homogenizing the crude emulsion to prepare a delivery system for fat-soluble nutrients.

[0009] Optionally, in step S10, the mass ratio of the rice bran polysaccharide to surfactin is 1:(2-20).

[0010] Optionally, step S20 includes: subjecting the freeze-dried product to a Maillard reaction under heating conditions, and then dialyzing to remove unreacted reactants to obtain a surfactin-rice bran polysaccharide conjugate.

[0011] Optionally, in step S20, the heating temperature is 50-90°C.

[0012] Optionally, in step S20, the reaction time of the Maillard reaction is 3 to 24 hours.

[0013] Optionally, in step S30, the stirring speed is 11000-13000 r / min.

[0014] Optionally, in step S40, the homogenization pressure is 4000-12000 psi.

[0015] Optionally, in step S40, the homogenization is performed 2 to 10 times.

[0016] Optionally, the fat-soluble nutrients include at least one of fat-soluble vitamins, carotenoids, flavonoids and unsaturated fatty acids.

[0017] In the technical solution provided by the present invention, a delivery system for fat-soluble nutrients is prepared, and the Maillard reaction for preparing a surfactant-rice bran polysaccharide conjugate occurs without adding chemical reagents, which is green and natural. The surfactant-rice bran polysaccharide conjugate based on the Maillard reaction has excellent emulsification ability, high surface activity and stable emulsification activity, antioxidant properties, pH value, temperature and ionic strength stability, and has great potential in constructing a fat-soluble nutrient delivery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 The A420nm and A294nm distribution diagrams of the surfactin-rice bran polysaccharide conjugates prepared in Examples 2 to 5 of the present invention are shown;

[0020] Figure 2 This is the EAI distribution diagram of the surfactin-rice bran polysaccharide conjugates prepared in Examples 5 to 9 of the present invention;

[0021] Figure 3 This is the ESI distribution diagram of the surfactin-rice bran polysaccharide conjugates prepared in Examples 5 to 9 of the present invention.

[0022] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. Where the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Fat-soluble nutrients in the diet have an important impact on human health, but due to their high hydrophobicity, low water solubility, poor processing stability, high permeability and other factors, their solubility in the gastrointestinal tract and oral bioavailability are low, and their application in the food field is subject to certain limitations.

[0025] In view of this, the present invention proposes a method for preparing a delivery system for fat-soluble nutrients, aiming to prepare a green nanoemulsion delivery system for fat-soluble nutrients with pH value, ionic strength and thermal stability.

[0026] The method for preparing the fat-soluble nutrient delivery system proposed by the present invention comprises the following steps:

[0027] S10, dissolving rice bran polysaccharide and surfactin in water, adjusting the pH to 7-11, and freeze-drying to obtain a freeze-dried product;

[0028] S20, subjecting the freeze-dried product to a Maillard reaction under heating conditions to obtain a surfactin-rice bran polysaccharide conjugate;

[0029] S30, dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase and stirring to obtain a crude emulsion;

[0030] S40, homogenizing the crude emulsion to prepare a delivery system for fat-soluble nutrients.

[0031] In the technical solution provided by the present invention, a delivery system for fat-soluble nutrients is prepared, and the Maillard reaction for preparing a surfactant-rice bran polysaccharide conjugate occurs without adding chemical reagents, which is green and natural. The surfactant-rice bran polysaccharide conjugate based on the Maillard reaction has excellent emulsification ability, high surface activity and stable emulsification activity, antioxidant properties, pH value, temperature and ionic strength stability, and has great potential in constructing a fat-soluble nutrient delivery system.

[0032] The presence of oil and its digestive hydrolysis effectively enhances the absorption efficiency of fat-soluble nutrients. Most studies also demonstrate a positive correlation between the bioaccessibility of fat-soluble nutrients and lipid digestion. Consequently, emulsions, composed of two phases of oil and water, offer unique advantages as nutrient delivery vehicles. Emulsion formation is closely linked to the properties of the stabilizer, which fundamentally determines the interfacial characteristics of the emulsion and, in turn, influences its physical and chemical properties.

[0033] Among biopolymers, proteins are the primary materials widely used in delivery systems. However, the effects of pH and ionic strength on protein structure can lead to precipitation (at the isoelectric point, pI) and aggregation. On the other hand, the use of methods such as coacervation, antisolvent precipitation, and emulsification-crosslinking has increased for the design of protein-based nanoparticles. However, the use of chemical crosslinker residues, such as glutaraldehyde and organic solvents, in these methods raises health concerns and may reduce the application of these vehicles for the targeted delivery of nutraceuticals. Furthermore, some lipid delivery systems, particularly nanoemulsions, are sometimes thermodynamically unstable. These issues can be addressed by anchoring Maillard-derived conjugates of proteoglycans on the surface of oil droplets as emulsifiers. Given their safety and stability, they are currently being used as promising delivery systems for bioactive compounds. The Maillard reaction occurs naturally without the addition of chemical reagents and has been widely used to enhance the functional and biological properties of proteins, peptides, and amino acids. Protein / peptide-sugar conjugates are currently used as emulsifiers, antioxidants, antimicrobial agents, gelling agents, and anti-browning compounds in food model systems and products. The conjugate also exhibits good stabilization capabilities, serving as a powerful delivery system to enhance the stability and bioaccessibility of many bioactive compounds.

[0034] Rice bran polysaccharides, a major component of rice bran, possess numerous physiological activities, including anti-tumor, immunity-boosting, antioxidant, and lipid- and blood-glucose-lowering properties. They are an excellent raw material for the production of health foods. Furthermore, even after gastrointestinal digestion, the polysaccharides retain their potent antioxidant and binding properties, demonstrating excellent digestive stability.

[0035] Surfactin, as a type of environmentally friendly surfactant of biological origin, has been studied as a model substance for biosurfactants in various fields. Surfactin is a lipopeptide composed of 7 amino acids (L-Glu→L-Leu→D-Leu→L-Val→L-Asp→D-Leu→L-Leu) and a carbon chain of 13 to 15 carbons. Glutamic acid (Glu) and aspartic acid (Asp) provide hydrophilic groups, while other amino acids and carbon chains provide hydrophobic groups. This molecular composition easily forms β-folds and "saddle-shaped" structures. This characteristic of surfactin gives it high surface activity and may have good potential for delivering fat-soluble nutrients.

[0036] In summary, the present invention proposes a method for constructing a novel fat-soluble nutrient delivery system based on a small molecule active peptide surfactant (Surfactin) modified natural macromolecular polysaccharide (rice bran polysaccharide), in order to provide a basis for increasing the added value of rice bran applications and promoting the research on fat-soluble nutrient delivery systems.

[0037] Optionally, in step S10, the mass ratio of the rice bran polysaccharide to the surfactin is 1:(2-20), for example, 1:2, 1:5, 1:10, 1:15, or 1:20. Under the above ratios, the reaction is more complete.

[0038] Specifically, in step S10, after adjusting the pH value to 7-11, the solution is stirred at room temperature for 5 hours to allow various substances therein to be evenly dispersed, and then freeze-dried.

[0039] Preferably, step S20 comprises: subjecting the freeze-dried product to a Maillard reaction under heating conditions, and then dialyzing to remove unreacted reactants to obtain a surfactin-rice bran polysaccharide conjugate.

[0040] The Maillard reaction, also known as the "non-enzymatic browning reaction," was proposed by French chemist LC Maillard in 1912. The Maillard reaction is a non-enzymatic browning process widely found in the food industry. It is a complex reaction between carbonyl compounds (reducing sugars) and amino compounds (amino acids and proteins). Ultimately, it produces the brown or even black macromolecule melanoidins, also known as pseudo-melanins, through a complex process. This is why it is also called the carbonyl-amino reaction.

[0041] Preferably, in step S20, the heating temperature is 50-90°C. The above reaction temperature allows for a more complete reaction.

[0042] Preferably, in step S20, the reaction time of the Maillard reaction is 3 to 24 hours. The above reaction time allows for a more complete reaction.

[0043] The specific operation of step S20 is as follows: the freeze-dried product is placed in a desiccator, a saturated KBr solution is placed at the bottom of the desiccator to provide a certain humidity (79% in the present embodiment). The Maillard reaction is carried out in an oven at a temperature of 50-90°C. The reaction is stopped after 3-24 hours. The resulting grafted product is dialyzed to remove unreacted surfactant, freeze-dried, and sealed and stored at 4°C for future use.

[0044] Preferably, in step S30, the stirring speed is 11000-13000 r / min. The stirring can be performed in a high-speed shearing machine, and the dispersion time can be 3 minutes, so that the solution is more fully emulsified.

[0045] It is understood that the type of oil in step S30 is not limited in this invention and can be any oil commonly used by those skilled in the art, such as soybean oil, peanut oil, fish oil, etc.

[0046] Preferably, in step S40, the homogenization pressure is 4000-12000 psi, where 1 psi = 6.895 kPa = 0.0689476 bar = 0.006895 MPa. Under the above pressure, the delivery system of the fat-soluble nutrients is more uniform.

[0047] Preferably, in step S40, the homogenization is performed 2 to 10 times. With the above homogenization times, the fat-soluble nutrient delivery system obtained is more uniform.

[0048] The present invention does not limit the type of the fat-soluble nutrients. Preferably, the fat-soluble nutrients include at least one of fat-soluble vitamins, carotenoids, flavonoids, and unsaturated fatty acids. The use of the above fat-soluble nutrients has a good absorption effect.

[0049] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0050] Example 1

[0051] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0052] (2) The solution obtained in (1) was frozen and freeze-dried, and the freeze-dried solid was placed in a desiccator. The humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 80°C for 8 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0053] (3) dissolving the fat-soluble nutrients in fish oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a crude emulsion;

[0054] (4) The crude emulsion was homogenized 6 times under a homogenization pressure of 4000 pis to prepare a delivery system for fat-soluble nutrients.

[0055] Example 2

[0056] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0057] (2) The solution obtained in (1) was frozen and freeze-dried, and the freeze-dried solid was placed in a desiccator. The humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 80°C for 3 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0058] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0059] (4) The crude emulsion was homogenized twice at a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0060] Example 3

[0061] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0062] (2) The solution obtained in (1) was frozen and then freeze-dried. The freeze-dried solid was placed in a desiccator and the humidity was controlled to 79% using a saturated potassium bromide solution. After Maillard reaction at 80°C for 6 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0063] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0064] (4) The crude emulsion was homogenized twice at a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0065] Example 4

[0066] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0067] (2) The solution obtained in (1) was frozen and then freeze-dried. The freeze-dried solid was placed in a desiccator and the humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 80°C for 12 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0068] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0069] (4) The crude emulsion was homogenized twice at a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0070] Example 5

[0071] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0072] (2) The solution obtained in (1) was frozen and freeze-dried, and the freeze-dried solid was placed in a desiccator. The humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 80°C for 24 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0073] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0074] (4) The crude emulsion was homogenized twice at a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0075] Example 6

[0076] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0077] (2) The solution obtained in (1) was frozen and freeze-dried, and the freeze-dried solid was placed in a desiccator. The humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 50°C for 24 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0078] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0079] (4) The crude emulsion was homogenized twice at a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0080] Example 7

[0081] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0082] (2) The solution obtained in (1) was frozen and freeze-dried, and the freeze-dried solid was placed in a desiccator. The humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 60°C for 24 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0083] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0084] (4) The crude emulsion was homogenized twice at a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0085] Example 8

[0086] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0087] (2) The solution obtained in (1) was frozen and freeze-dried, and the freeze-dried solid was placed in a desiccator. The humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 70°C for 24 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0088] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0089] (4) The crude emulsion was homogenized twice under a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0090] Example 9

[0091] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 8.0 at a ratio of 1:2 (w / w) so that the surfactin content was 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0092] (2) The solution obtained in (1) was frozen and then freeze-dried. The freeze-dried solid was placed in a desiccator and the humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 90°C for 24 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0093] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0094] (4) The crude emulsion was homogenized twice under a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0095] Example 10

[0096] (1) Rice bran polysaccharide and surfactin were dissolved in a phosphate buffer solution with a pH value of 11 at a ratio of 1:20 (w / w) to obtain a surfactin content of 0.05%, and the mixture was stirred continuously in a constant temperature magnetic stirrer for 5 hours.

[0097] (2) The solution obtained in (1) was frozen and then freeze-dried. The freeze-dried solid was placed in a desiccator and the humidity was controlled to 79% using a saturated potassium bromide solution. After the Maillard reaction was carried out at 90°C for 24 hours, a surfactant-rice bran polysaccharide conjugate was obtained. The obtained product was stored in a -4°C refrigerator.

[0098] (3) dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase, and dispersing the mixture at high speed at 12,000 rpm for 3 minutes using a high-speed shearing machine to obtain a coarse emulsion;

[0099] (4) The crude emulsion was homogenized twice under a homogenization pressure of 12000 pis to prepare a delivery system for fat-soluble nutrients.

[0100] 1. The surfactin-rice bran polysaccharide conjugate prepared in step (2) of Example 1 was subjected to infrared spectroscopy: The surfactin-rice bran polysaccharide conjugate powder was thoroughly ground with KBr, pressed into tablets, and then subjected to infrared spectroscopy on a Fourier transform infrared spectrometer. The obtained spectrum was fitted using Peakfit software to obtain the secondary structure distribution, as shown in Table 1.

[0101] Table 1 Infrared spectrum of surfactin-rice bran polysaccharide conjugate of Example 1 Figure 2 Level structure distribution

[0102]

[0103] Table 1 shows the successful preparation of the Maillard conjugate, demonstrating the changes in secondary structure. The increase in α-helix and β-sheet after the Maillard reaction indicates enhanced hydrogen bonding between peptide chains. Compared to surfactin alone, the conjugate exhibits a more stable secondary structure. The increase in random coils also provides more flexibility in the spatial conformation of the surfactin-rice bran polysaccharide conjugate.

[0104] 2. The surfactant-rice bran polysaccharide conjugate prepared in step (2) of Examples 2 to 5 was diluted with ultrapure water to 0.5 mg / mL, and ultrapure water was used as a blank control. A420nm, i.e., the browning degree of the conjugate, was measured at a wavelength of 420nm using a UV-visible spectrophotometer, and A294nm, representing the intermediate product of the Maillard reaction, was measured at 294nm. Figure 1 , Figure 1 The reaction time (Reaction Time) in the middle horizontal axis is 3h, which is Example 2, and so on.

[0105] Depend on Figure 1 It can be seen that as the reaction time increases, the absorbance of the surfactant-rice bran polysaccharide conjugate at 294 or 420 nm increases significantly, indicating that as the Maillard reaction proceeds, colored intermediates and final products are generated and accumulated.

[0106] 3. The surfactin-rice bran polysaccharide conjugates prepared in step (2) of Examples 5 to 9 were tested for zeta potential, particle size and PdI of the conjugates obtained at different reaction temperatures using a Malvern laser particle size analyzer, and the results are shown in Table 2.

[0107] Table 2 Zeta potential, particle size and PdI of surfactin-rice bran polysaccharide conjugates of Examples 5 to 9

[0108]

[0109] As shown in Table 2, the particle size distribution of the surfactant-rice bran polysaccharide conjugates obtained at different reaction temperatures ranged widely. This suggests that peptide degradation and cross-linking during the Maillard reaction may have led to higher polydispersity. Notably, the product obtained at 90°C exhibited a very concentrated particle size distribution, with a PdI of 0.19, indicating that peptide-peptide and peptide-polysaccharide aggregation at high temperatures tended to achieve size uniformity. However, the potential of the reaction product decreased to -15.23 mV at 90°C, indicating that more oxidants may have formed during the high-temperature reaction, a property that is detrimental to the formation of stable emulsions.

[0110] 4. The emulsifying activity (EAI) and emulsifying stability (ESI) of the surfactant-rice bran polysaccharide conjugate prepared in step (2) of Examples 5 to 9 were tested. The surfactant-rice bran polysaccharide conjugate prepared in (2) was dissolved in deionized water and 1% fish oil was added. The mixture was dispersed at a high speed of 12000 r / min for 3 minutes. 100 microliters of the emulsion was drawn from the emulsion at 0 minute and 10 minutes respectively, and added to 9.9 mL of 1% SDS solution. The absorbance was measured at 500 nm. The SDS solution was used as a blank control. The results were as follows: Figure 2 and Figure 3 .

[0111] like Figure 2 and Figure 3 As shown, at 80°C (Example 5), the ESI and EAI values ​​of the surfactant-rice bran polysaccharide conjugate were the highest. There were significant differences in the ESI values ​​at all temperature levels. Compared with the high temperature of 90°C, the surfactant-rice bran polysaccharide conjugate heated at 80°C showed significantly improved emulsification activity and emulsion stability. This is because higher temperatures will turn the sample brown and lead to reduced solubility and damage of small molecule peptides, resulting in reduced absorption of the interfacial layer, thereby weakening the stability of the emulsion. Related studies have shown that heating natural globular proteins to above their denaturation temperature will cause the protein structure to open and bind to the polysaccharide to stabilize the electrostatic interaction. This result is consistent with the test results shown by the zeta potential.

[0112] 5. Take 1 mL of the fat-soluble nutrient delivery system prepared in Example 1, add 5 mL of methanol, vortex for 5 minutes, and centrifuge at 5000 rpm for 10 minutes to obtain the supernatant. Measure the absorbance of the supernatant at a wavelength of 216 nm using methanol as a control, which is the absorbance of the total drug dose, A1.

[0113] 2 mL of the fat-soluble nutrient delivery system prepared in Example 1 was measured and placed in a centrifuge tube. An appropriate amount of petroleum ether was added and vortexed. After standing and stratification, the lower layer of suspension was taken, 1 mL of the suspension was aspirated, 5 mL of methanol was added, and the absorbance was measured at a wavelength of 216 nm with methanol as the control. The content of the encapsulated drug was determined and recorded as A2.

[0114] Encapsulation efficiency EE (%) = encapsulated drug mass / total drug amount added = 78.84%

[0115] That is, the fat-soluble nutrient delivery system prepared under these conditions has good encapsulation efficiency. Overall, the Maillard reaction between surfactant and rice bran polysaccharide under dry conditions greatly improved the surface activity of rice bran polysaccharide, providing a basis for modifying natural macromolecular polysaccharides to construct fat-soluble nutrient delivery systems.

[0116] In summary, the present invention prepares a delivery system for fat-soluble nutrients, and the Maillard reaction for preparing the surfactant-rice bran polysaccharide conjugate occurs without adding chemical reagents, which is green and natural; the surfactant-rice bran polysaccharide conjugate based on the Maillard reaction has excellent emulsification ability, high surface activity and stable emulsification activity, antioxidant properties, pH value, temperature and ionic strength stability, and has great potential in constructing a fat-soluble nutrient delivery system.

[0117] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. A method for preparing a delivery system for fat-soluble nutrients, characterized in that: The following steps are involved: S10, dissolving rice bran polysaccharide and surfactin in water, adjusting the pH to 7-11, and freeze-drying to obtain a freeze-dried product; S20, subjecting the freeze-dried product to a Maillard reaction under heating conditions to obtain a surfactin-rice bran polysaccharide conjugate, wherein the heating temperature is 50 to 90° C. and the Maillard reaction time is 3 to 24 hours; S30, dissolving the fat-soluble nutrients in oil to form an oil phase, dissolving the surfactant-rice bran polysaccharide conjugate in water, adding the oil phase and stirring to obtain a crude emulsion; S40, homogenizing the crude emulsion to prepare a delivery system for fat-soluble nutrients.

2. The method for preparing the fat-soluble nutrient delivery system according to claim 1, wherein: In step S10, the mass ratio of the rice bran polysaccharide to the surfactin is 1:(2-20).

3. The method for preparing the fat-soluble nutrient delivery system according to claim 1, wherein: Step S20 includes: subjecting the freeze-dried product to a Maillard reaction under heating conditions, and then dialyzing to remove unreacted reactants to obtain a surfactin-rice bran polysaccharide conjugate.

4. The method for preparing the fat-soluble nutrient delivery system according to claim 1, wherein: In step S30, the stirring speed is 11000-13000 r / min.

5. The method for preparing the fat-soluble nutrient delivery system according to claim 1, wherein: In step S40, the homogenization pressure is 4000-12000 psi.

6. The method for preparing the fat-soluble nutrient delivery system according to claim 1, wherein: In step S40, the homogenization is performed 2 to 10 times.

7. The method for preparing the fat-soluble nutrient delivery system according to claim 1, wherein: The fat-soluble nutrients include at least one of fat-soluble vitamins, carotenoids, flavonoids and unsaturated fatty acids.

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