A bio-based hydrogel nutrient delivery system and method of making the same

Abstract

The present application relates to a kind of bio-based hydrogel nutrient delivery system and its preparation method, preparation method includes the following steps: step 1: burdock nanocellulose preparation.Step 2: whey protein isolate preheating.Step 3: nanocellulose / whey protein isolate normal temperature compound.Step 4: secondary heating.Step 5: cold storage.The nutrient delivery system of the present application is simple to operate, cost controllable and environmentally friendly.The preheating of whey protein isolate and the introduction of nanocellulose synergistically enhance the stability of the hydrogel, effectively inhibiting the degradation of the encapsulated nutrients and delaying the gastrointestinal release of the nutrients.

Description

Technical Field

[0001] This invention relates to a bio-based hydrogel nutrient delivery system and its preparation method, belonging to the field of nutrient delivery technology. Background Technology

[0002] Diet is closely related to human health. Nutrients in natural foods, including peptides, polysaccharides, polyphenols, functional lipids, and probiotics, possess outstanding biological benefits, such as antioxidant, anti-inflammatory, and glucose and lipid metabolism regulation. However, these nutrients undergo degradation and activity reduction during processing, transportation, and storage. Furthermore, during in vivo processing, many nutrients suffer from short retention times, poor targeting, and easy metabolism, leading to low bioavailability and limited efficacy. Therefore, constructing delivery systems adapted to nutrient structures is an effective way to overcome these problems. Hydrogels, three-dimensional network structures formed by cross-linked hydrophilic polymer chains, can absorb large amounts of water and possess outstanding structural stability and biocompatibility, showing broad application prospects in the steady-state processing and targeted delivery of active substances.

[0003] Whey protein isolate (WPI) possesses excellent emulsifying, gelling, and foaming properties, making it widely used in the food industry. However, forming hydrogels from WPI alone often requires high concentrations and results in unstable and easily broken structures. Therefore, researchers have explored ways to improve its stability by introducing polysaccharides and cross-linking agents. For example, patent 202111657703.8 discloses a method for preparing a chitosan / WPI gel encapsulating β-carotene. Chitosan and WPI are mixed, followed by the addition of MCT (methyl methacrylate) to dissolve β-carotene and emulsification. Ultra-high pressure treatment promotes the formation of a gel from the mixed solution. In patent 202310123562.4, WPI is first heated under acidic conditions to form a protein fiber structure, followed by the sequential addition of curcumin and pectin to form a hydrogel structure encapsulating curcumin. Cellulose nanofiber (CNF) is a fibrous aggregate with a diameter less than 100 nm and a length reaching micrometers. It has better mechanical properties than ordinary polysaccharides and possesses good biocompatibility. The application of nanocellulose in enhancing the properties of hydrogels has also received widespread attention. However, reports on WPI and nanocellulose composite hydrogels are still very limited. Summary of the Invention

[0004] Purpose of the invention: To address the existing problems and shortcomings, this invention reports a hydrogel nutrient delivery system based on whey protein isolate and nanocellulose and its preparation method. Through steps such as burdock CNF preparation, preheating, compounding, secondary heating, and cooling, a stable hydrogel structure is obtained, thereby effectively improving the nutrient homeostasis protection effect.

[0005] Technical solution: To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] A bio-based hydrogel nutrient delivery system and its preparation method, characterized by comprising the following steps:

[0007] Step 1: Preparation of burdock CNF

[0008] Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. The obtained burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. Then, 0.15% (w / w) α-amylase (60℃, pH 4.5) was added for 40 min, 0.20% (w / w) saccharifying enzyme (60℃, pH 6.0) was added for 40 min, and 1.0% (w / w) papain (50℃, pH 6.0) was added for 60 min. After each enzymatic hydrolysis, the enzymes were inactivated by boiling in a water bath. After centrifugation at 5000g for 20 min, a light gray precipitate was obtained, which was burdock insoluble dietary fiber (IDF). The burdock IDF was washed three times with water and ethanol, and then freeze-dried. Burdock IDF was mixed with 50 volumes of sodium citrate buffer (50 mM, pH 4.8) containing xylanase (2000 U / mL) and cellulase (3000 U / mL), and reacted at 50 °C and 600 rpm for 18–30 h. The sample was then boiled for 5 min to inactivate the enzymes. The enzymatic hydrolysate was sonicated at 600 W for 3 h, centrifuged at 1000 g to remove unconverted burdock IDF, and then centrifuged at 5000 g to obtain burdock CNF precipitate. This precipitate was transferred to a dialysis bag with a molecular weight cutoff of 8000–14000 kDa and dialyzed to remove impurities.

[0009] Step 2: Preheating

[0010] Prepare a 10% (w / w) WPI aqueous solution, adjust the pH of the solution to 1.5–8.0, and then heat it at 60–95°C for 2 hours. After heating, adjust the pH to 7.5.

[0011] Step 3: Room temperature lamination,

[0012] Prepare a burdock CNF suspension with a concentration of 0.5–2% (w / w). Mix the preheated WPI solution with the CNF suspension at a volume ratio of 3:1 to 1:1 and stir until homogeneous to obtain solution I. Mix solution I with calcium chloride solution (1.0%, w / w) at a volume ratio of 9:1 and stir until homogeneous to obtain solution II. Mix solution II with a hydrophilic nutrient aqueous solution (0.5–10%, w / w) or a hydrophobic nutrient ethyl acetate solution (0.5–10%, w / w) at a volume ratio of 10:1 and stir until homogeneous to obtain solution III.

[0013] Step 4: Second heating,

[0014] Heat solution III at 70–100°C for 10–40 min and then cool to room temperature;

[0015] Step 5: Let it cool.

[0016] The above solution was left to stand at 4°C overnight to form a gel.

[0017] Furthermore, in step 2, the WPI aqueous solution is adjusted to pH 2.0 or 7.0, and the heating temperature is 80-90℃.

[0018] Furthermore, in step 3, the concentration of the burdock CNF suspension is 1.0–1.5% (w / w).

[0019] Furthermore, in step 3, the volume ratio of the preheated WPI solution to the CNF suspension is 2:1 to 2.5:1.

[0020] Furthermore, in step 3, the concentration of the hydrophilic nutrient aqueous solution or the hydrophobic nutrient ethyl acetate solution is 8–10% (w / w).

[0021] Furthermore, in step 4, the heating temperature of solution III is 75–85°C, and the heating time is 25–35 min.

[0022] A bio-based hydrogel nutrient delivery system and its preparation method, comprising the method described in any one of claims 1-6.

[0023] A bio-based hydrogel nutrient delivery system and its preparation method are disclosed, wherein nutrients are loaded into the bio-based hydrogel nutrient delivery system described in claims 1-6, and after assembly, the system is used as a functional ingredient in various forms of food.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following advantages: it utilizes preheating treatment and the introduction of burdock nanocellulose to improve the structural density of the gel and enhance the steady-state protection effect on the encapsulating core material. The method is simple, feasible and environmentally friendly, and has potential industrial application prospects. Attached Figure Description

[0025] Figure 1 These are schematic diagrams illustrating the preparation of hydrogels in embodiments and control groups of the present invention;

[0026] Figure 2 These are electrophoretic images of hydrogels from embodiments and control groups of the present invention;

[0027] Figure 3 These are scanning electron microscope images of hydrogels from embodiments and control groups of the present invention;

[0028] Figure 4 These are the hydrogel texture detection results of the embodiments and control group of the present invention;

[0029] Figure 5 The encapsulation efficiency of anthocyanins in the hydrogels of the embodiments and control group of the present invention;

[0030] Figure 6 These are small-angle oscillation frequency scans of the hydrogels in the embodiments and control group of the present invention;

[0031] Figure 7 These are small-angle oscillation temperature scans of the hydrogels in the embodiments and control group of the present invention;

[0032] Figure 8 This describes the storage stability of anthocyanins encapsulated in hydrogels in the embodiments and control group of the present invention;

[0033] Figure 9 This describes the gastrointestinal release characteristics of anthocyanins encapsulated in hydrogels in the embodiments and control group of the present invention. Detailed Implementation

[0034] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0035] like Figure 1 The steps shown illustrate a bio-based hydrogel nutrient delivery system and its preparation method. Two examples are given below for illustration.

[0036] Example 1

[0037] Step 1: Preparation of burdock CNF

[0038] Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. The obtained burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. Then, 0.15% (w / w) α-amylase (60℃, pH 4.5) was added for 40 min, 0.20% (w / w) saccharifying enzyme (60℃, pH 6.0) was added for 40 min, and 1.0% (w / w) papain (50℃, pH 6.0) was added for 60 min. After each enzymatic hydrolysis, the enzymes were inactivated by boiling in a water bath. After centrifugation at 5000g for 20 min, a light gray precipitate was obtained, which was burdock insoluble dietary fiber (IDF). The burdock IDF was washed three times with water and ethanol, and then freeze-dried. Burdock IDF was mixed with 50 volumes of sodium citrate buffer (50 mM, pH 4.8) containing xylanase (2000 U / mL) and cellulase (3000 U / mL), and reacted at 50 °C and 600 rpm for 18–30 h. The sample was then boiled for 5 min to inactivate the enzymes. The enzymatic hydrolysate was sonicated at 600 W for 3 h, centrifuged at 1000 g to remove unconverted burdock IDF, and then centrifuged at 5000 g to obtain burdock CNF precipitate. This precipitate was transferred to a dialysis bag with a molecular weight cutoff of 8000–14000 kDa and dialyzed to remove impurities.

[0039] Step 2: Preheating

[0040] Prepare a 10% (w / w) WPI aqueous solution, adjust the pH of the solution to 2.0, and then heat it at 85°C for 2 hours. After heating, adjust the pH to 7.5.

[0041] Step 3: Room temperature lamination,

[0042] Prepare a 1.0% (w / w) burdock CNF suspension. Mix the preheated WPI solution with the CNF suspension at a volume ratio of 2:1 and stir until homogeneous to obtain solution I. Mix solution I with calcium chloride solution (1.0%, w / w) at a volume ratio of 9:1 and stir until homogeneous to obtain solution II. Mix solution II with anthocyanin aqueous solution (10%, w / w) at a volume ratio of 10:1 and stir until homogeneous to obtain solution III.

[0043] Step 4: Second heating,

[0044] Solution III was heated at 80°C for 30 minutes and then cooled to room temperature;

[0045] Step 5: Let it cool.

[0046] The above solution was left at 4°C overnight to form a gel, which was named WNG-H2.

[0047] Example 2

[0048] Step 1: Preparation of burdock CNF

[0049] Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. The obtained burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. Then, 0.15% (w / w) α-amylase (60℃, pH 4.5) was added for 40 min, 0.20% (w / w) saccharifying enzyme (60℃, pH 6.0) was added for 40 min, and 1.0% (w / w) papain (50℃, pH 6.0) was added for 60 min. After each enzymatic hydrolysis, the enzymes were inactivated by boiling in a water bath. After centrifugation at 5000g for 20 min, a light gray precipitate was obtained, which was burdock insoluble dietary fiber (IDF). The burdock IDF was washed three times with water and ethanol, and then freeze-dried. Burdock IDF was mixed with 50 volumes of sodium citrate buffer (50 mM, pH 4.8) containing xylanase (2000 U / mL) and cellulase (3000 U / mL), and reacted at 50 °C and 600 rpm for 18–30 h. The sample was then boiled for 5 min to inactivate the enzymes. The enzymatic hydrolysate was sonicated at 600 W for 3 h, centrifuged at 1000 g to remove unconverted burdock IDF, and then centrifuged at 5000 g to obtain burdock CNF precipitate. This precipitate was transferred to a dialysis bag with a molecular weight cutoff of 8000–14000 kDa and dialyzed to remove impurities.

[0050] Step 2: Preheating

[0051] Prepare a 10% (w / w) WPI aqueous solution, adjust the pH of the solution to 7.0, and then heat it at 85°C for 2 hours. After heating, adjust the pH to 7.5.

[0052] Step 3: Room temperature lamination,

[0053] Prepare a 1.0% (w / w) burdock CNF suspension. Mix the preheated WPI solution with the burdock CNF suspension at a volume ratio of 2:1 and stir until homogeneous to obtain solution I. Mix solution I with calcium chloride solution (1.0%, w / w) at a volume ratio of 9:1 and stir until homogeneous to obtain solution II. Mix solution II with anthocyanin aqueous solution (10%, w / w) at a volume ratio of 10:1 and stir until homogeneous to obtain solution III.

[0054] Step 4: Second heating,

[0055] Solution III was heated at 80°C for 30 minutes and then cooled to room temperature;

[0056] Step 5: Let it cool.

[0057] The above solution was left at 4°C overnight to form a gel, which was named WNG-H7.

[0058] Control group 1

[0059] Step 1: Preparation of burdock CNF

[0060] Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. The obtained burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. Then, 0.15% (w / w) α-amylase (60℃, pH 4.5) was added for 40 min, 0.20% (w / w) saccharifying enzyme (60℃, pH 6.0) was added for 40 min, and 1.0% (w / w) papain (50℃, pH 6.0) was added for 60 min. After each enzymatic hydrolysis, the enzymes were inactivated by boiling in a water bath. After centrifugation at 5000g for 20 min, a light gray precipitate was obtained, which was burdock insoluble dietary fiber (IDF). The burdock IDF was washed three times with water and ethanol, and then freeze-dried. Burdock IDF was mixed with 50 volumes of sodium citrate buffer (50 mM, pH 4.8) containing xylanase (2000 U / mL) and cellulase (3000 U / mL), and reacted at 50 °C and 600 rpm for 18–30 h. The sample was then boiled for 5 min to inactivate the enzymes. The enzymatic hydrolysate was sonicated at 600 W for 3 h, centrifuged at 1000 g to remove unconverted burdock IDF, and then centrifuged at 5000 g to obtain burdock CNF precipitate. This precipitate was transferred to a dialysis bag with a molecular weight cutoff of 8000–14000 kDa and dialyzed to remove impurities.

[0061] Step 2: Preheating

[0062] Prepare a 10% (w / w) WPI aqueous solution, adjust the pH of the solution to 2.0, and then heat it at 85°C for 2 hours. After heating, adjust the pH to 7.5.

[0063] Step 3: Room temperature lamination,

[0064] The preheated WPI solution was mixed with distilled water at a volume ratio of 2:1 and stirred until homogeneous to obtain solution I; solution I was mixed with calcium chloride solution (1.0%, w / w) at a volume ratio of 9:1 and stirred until homogeneous to obtain solution II; solution II was mixed with anthocyanin aqueous solution (10%, w / w) at a volume ratio of 10:1 and stirred until homogeneous to obtain solution III.

[0065] Step 4: Second heating,

[0066] Solution III was heated at 80°C for 30 minutes and then cooled to room temperature;

[0067] Step 5: Let it cool.

[0068] The above solution was left at 4°C overnight to form a gel, which was named WG-H2.

[0069] Control group 2

[0070] Step 1: Preparation of burdock CNF

[0071] Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. The obtained burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. Then, 0.15% (w / w) α-amylase (60℃, pH 4.5) was added for 40 min, 0.20% (w / w) saccharifying enzyme (60℃, pH 6.0) was added for 40 min, and 1.0% (w / w) papain (50℃, pH 6.0) was added for 60 min. After each enzymatic hydrolysis, the enzymes were inactivated by boiling in a water bath. After centrifugation at 5000g for 20 min, a light gray precipitate was obtained, which was burdock insoluble dietary fiber (IDF). The burdock IDF was washed three times with water and ethanol, and then freeze-dried. Burdock IDF was mixed with 50 volumes of sodium citrate buffer (50 mM, pH 4.8) containing xylanase (2000 U / mL) and cellulase (3000 U / mL) and reacted at 50 °C and 600 rpm for 18–30 h. The sample was then boiled for 5 min to inactivate the enzymes. The enzymatic hydrolysate was sonicated at 600 W for 3 h, centrifuged at 1000 g to remove unconverted burdock IDF, and then centrifuged at 5000 g to obtain burdock CNF precipitate. This precipitate was then transferred to a dialysis bag with a molecular weight cutoff of 8000–14000 kDa to remove impurities.

[0072] Step 2: Preheating

[0073] Prepare a 10% (w / w) WPI aqueous solution, adjust the pH of the solution to 7.0, and then heat it at 85°C for 2 hours. After heating, adjust the pH to 7.5.

[0074] Step 3: Room temperature lamination,

[0075] The preheated WPI solution was mixed with distilled water at a volume ratio of 2:1 and stirred until homogeneous to obtain solution I; solution I was mixed with calcium chloride solution (1.0%, w / w) at a volume ratio of 9:1 and stirred until homogeneous to obtain solution II; solution II was mixed with anthocyanin aqueous solution (10%, w / w) at a volume ratio of 10:1 and stirred until homogeneous to obtain solution III.

[0076] Step 4: Second heating,

[0077] Solution III was heated at 80°C for 30 minutes and then cooled to room temperature;

[0078] Step 5: Let it cool.

[0079] The above solution was left at 4°C overnight to form a gel, which was named WG-H7.

[0080] Control group 3

[0081] Step 1: Preparation of burdock CNF

[0082] Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. The obtained burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. Then, 0.15% (w / w) α-amylase (60℃, pH 4.5) was added for 40 min, 0.20% (w / w) saccharifying enzyme (60℃, pH 6.0) was added for 40 min, and 1.0% (w / w) papain (50℃, pH 6.0) was added for 60 min. After each enzymatic hydrolysis, the enzymes were inactivated by boiling in a water bath. After centrifugation at 5000g for 20 min, a light gray precipitate was obtained, which was burdock insoluble dietary fiber (IDF). The burdock IDF was washed three times with water and ethanol, and then freeze-dried. Burdock IDF was reacted with 50 volumes of sodium citrate buffer (50 mM, pH 4.8) containing xylanase (2000 U / mL) and cellulase (3000 U / mL) at 50 °C and 600 rpm for 18–30 h. The samples were then boiled for 5 min to inactivate the enzymes. The enzymatic hydrolysate was sonicated at 600 W for 3 h, centrifuged at 1000 g to remove unconverted burdock IDF, and then centrifuged at 5000 g to obtain burdock CNF precipitate. This precipitate was transferred to a dialysis bag with a molecular weight cutoff of 8000–14000 kDa and dialyzed to remove impurities.

[0083] Step 2: Solution preparation,

[0084] Prepare a 10% (w / w) WPI aqueous solution, adjust the pH of the solution to 7.5, and do not preheat it;

[0085] Step 3: Room temperature lamination,

[0086] Prepare a 1.0% (w / w) burdock CNF suspension by mixing WPI solution and burdock CNF suspension at a volume ratio of 2:1 and stirring until homogeneous to obtain solution I; mix solution I with calcium chloride solution (1.0%, w / w) at a volume ratio of 9:1 and stir until homogeneous to obtain solution II; mix solution II with anthocyanin aqueous solution (10%, w / w) at a volume ratio of 10:1 and stir until homogeneous to obtain solution III.

[0087] Step 4: Second heating,

[0088] Solution III was heated at 80°C for 30 minutes and then cooled to room temperature;

[0089] Step 5: Let it cool.

[0090] The above solution was left to stand at 4°C overnight to form a gel, which was named WNG.

[0091] Control group 4

[0092] Step 1: Preparation of burdock CNF

[0093] Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. The obtained burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. Then, 0.15% (w / w) α-amylase (60℃, pH 4.5) was added for 40 min, 0.20% (w / w) saccharifying enzyme (60℃, pH 6.0) was added for 40 min, and 1.0% (w / w) papain (50℃, pH 6.0) was added for 60 min. After each enzymatic hydrolysis, the enzymes were inactivated by boiling in a water bath. After centrifugation at 5000g for 20 min, a light gray precipitate was obtained, which was burdock insoluble dietary fiber (IDF). The burdock IDF was washed three times with water and ethanol, and then freeze-dried. Burdock IDF was reacted with 50 volumes of sodium citrate buffer (50 mM, pH 4.8) containing xylanase (2000 U / mL) and cellulase (3000 U / mL) at 50 °C and 600 rpm for 18–30 h. The samples were then boiled for 5 min to inactivate the enzymes. The enzymatic hydrolysate was sonicated at 600 W for 3 h, centrifuged at 1000 g to remove unconverted burdock IDF, and then centrifuged at 5000 g to obtain burdock CNF precipitate. This precipitate was transferred to a dialysis bag with a molecular weight cutoff of 8000–14000 kDa and dialyzed to remove impurities.

[0094] Step 2: Solution preparation,

[0095] Prepare a 10% (w / w) WPI aqueous solution, adjust the pH of the solution to 7.5, and do not preheat it;

[0096] Step 3: Room temperature lamination,

[0097] WPI solution and distilled water were mixed at a volume ratio of 2:1 and stirred until homogeneous to obtain solution I; solution I was mixed with calcium chloride solution (1.0%, w / w) at a volume ratio of 9:1 and stirred until homogeneous to obtain solution II; solution II was mixed with anthocyanin aqueous solution (10%, w / w) at a volume ratio of 10:1 and stirred until homogeneous to obtain solution III.

[0098] Step 4: Second heating,

[0099] Solution III was heated at 80°C for 30 minutes and then cooled to room temperature;

[0100] Step 5: Let it cool.

[0101] The above solution was left to stand at 4°C overnight to form a gel, which was named WG.

[0102] Efficacy testing

[0103] like Figure 2 As shown, Examples 1 (WNG-H2), 2 (WNG-H7), and Control Groups 1 (WG-H2) and 2 (WG-H7) formed relatively stable gels that did not slip when the bottles were inverted; however, Control Groups 3 (WG) and 4 (WNG) exhibited relatively poor gel stability and water leaching. SEM images of the six samples (…) Figure 3 As can be seen from the data, compared with the WG, WG-H2, and WG-H7 gel samples, the corresponding hydrogels with added burdock CNF (WHG, WHG-H2, and WHG-H7) have a relatively denser structure. Texture analysis results show that... Figure 4 Burdock CNF can effectively improve the chewiness, hardness, crispness, elasticity, and viscosity of hydrogels. Additionally, from... Figure 5 As can be seen, compared with the control group, the encapsulation efficiency of anthocyanins in the hydrogels WNG-H2 and WNG-H7 of the two examples was significantly higher than that in the four control group hydrogels. These results indicate that preheating and CNF compounding have a synergistic effect on gel stability.

[0104] Small-angle oscillation scanning results indicate that ( Figure 6 , Figure 7 The hydrogels of Examples 1 (WNG-H2) and 2 (WNG-H7) had higher elastic and viscous moduli than the control group hydrogels, demonstrating that preheating and CNF addition can significantly promote intermolecular interactions, thereby reducing the fluidity of the gel.

[0105] from Figure 8 As can be seen, the hydrogels in Examples 1 (WNG-H2) and 2 (WNG-H7) showed better protection of encapsulated anthocyanins at 4°C and 37°C than the four control group hydrogels; from Figure 9 As can be seen from the results, compared with the control group hydrogel, the hydrogel in this example can play a more effective role in gastrointestinal controlled release.

[0106] The results show that this system prepares a bio-based hydrogel nutrient delivery system through CNF preparation, preheating, compounding, secondary heating, and cooling. It has high stability and improves the stability of encapsulated nutrients and the sustained release properties in the digestive tract.

[0107] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing a bio-based hydrogel nutrient delivery system, characterized in that: The steps include: Step 1: Preparation of burdock CNF, Fresh burdock was selected as raw material, washed, dried, ultra-finely pulverized, and sieved to obtain burdock powder. 100g of burdock powder was mixed with distilled water at a mass ratio of 1:5 and magnetically stirred until evenly dispersed. 0.15% w / w α-amylase was added and treated at 60℃ and pH 4.5 for 40min; 0.20% w / w saccharifying enzyme was added and treated at 60℃ and pH 6.0 for 40min. Papain (1.0% w / w) was used to treat the burdock IDF at 50°C and pH 6.0 for 60 min. After each enzymatic hydrolysis step, the enzymes were inactivated by boiling in a water bath. The hydrolysate was centrifuged at 5000 g / min for 20 min to obtain a light gray precipitate, which was burdock IDF. The burdock IDF was washed three times with water and ethanol, and then freeze-dried. The burdock IDF was then mixed with 50 volumes of 50 mM aqueous solution containing 2000 U / mL xylanase and 3000 U / mL cellulase at pH 6.

0. 4.8 The sample was mixed with sodium citrate buffer and reacted at 50℃ and 600r / min for 18–30 h. The sample was then boiled for 5 min to inactivate the enzyme. The enzyme hydrolysate was treated with sonication at 600W for 3 h. Unconverted burdock IDF was removed by centrifugation at 1000g. The burdock CNF precipitate was then obtained by centrifugation at 5000g and transferred to a dialysis bag with a molecular weight cutoff of 8000–14000kDa for dialysis to remove impurities. Step 2: Preheating Prepare a 10% w / w WPI aqueous solution, adjust the pH of the solution to 2.0 or 7.0, and then heat it at 80-90℃ for 2 hours. After heating, adjust the pH to 7.

5. Step 3: Room temperature lamination, Prepare a burdock CNF suspension with a concentration of 1.0–1.5% w / w. Mix the preheated WPI solution with the CNF suspension at a volume ratio of 3:1 to 1:1 and stir until homogeneous to obtain solution I. Mix solution I with a 1.0% w / w calcium chloride solution at a volume ratio of 9:1 and stir until homogeneous to obtain solution II. Mix solution II with a 0.5–10% w / w hydrophilic nutrient aqueous solution or a 0.5–10% w / w hydrophobic nutrient ethyl acetate solution at a volume ratio of 10:1 and stir until homogeneous to obtain solution III. Step 4: Second heating, Heat solution III at 70–100°C for 10–40 min and then cool to room temperature; Step 5: Let it cool. The above solution was left to stand at 4°C overnight to form a gel.

2. The method for preparing a bio-based hydrogel nutrient delivery system according to claim 1, characterized in that: In step 3, the volume ratio of the preheated WPI solution to the CNF suspension is 2:1 to 2.5:

1.

3. The method for preparing a bio-based hydrogel nutrient delivery system according to claim 1, characterized in that: In step 3, the concentration of the hydrophilic nutrient aqueous solution or the hydrophobic nutrient ethyl acetate solution is 8-10% w / w.

4. The method for preparing a bio-based hydrogel nutrient delivery system according to claim 1, characterized in that: In step 4, the heating temperature of solution III is 75–85°C, and the heating time is 25–35 min.

5. A bio-based hydrogel nutrient delivery system, characterized in that: Made by the method described in any one of claims 1-4.

6. An application of a bio-based hydrogel nutrient delivery system, characterized in that: Nutrients are loaded into a bio-based hydrogel nutrient delivery system prepared by any of the methods described in claims 1-4, and after assembly, it is used as a functional ingredient in different forms of food.

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