Preparation method of wheat gliadin / soybean protein isolate nanoparticle embedded astaxanthin

Abstract

The invention discloses a preparation method of wheat gliadin / soybean protein isolate nanoparticle embedded astaxanthin, and belongs to the field of functional food. The preparation process comprises the following steps: (1) weighing wheat gliadin and soybean protein isolate according to different proportions; (2) dissolving the samples in different proportions in distilled water; (3) stirring the mixed liquid for 1 hour under the condition of 600 r / min; (4) carrying out ultrasonic dispersion treatment on the protein solution to promote the expansion of the protein structure; (5) adding the astaxanthin ethanol solution into the protein solution, and stirring for 1 hour under the condition of 600 r / min; (6) slowly adjusting the pH value of the mixed system to 7.0 by using a 1M citric acid solution; and (7) carrying out centrifugal treatment on the mixed system, and taking supernate to obtain the G / SPI nano-particles and the G / SPI / ASTA nano-particles. According to the preparation method, the double-protein nano-particles prepared by adopting a PH driving method have good stability, the embedding rate of astaxanthin is greatly improved, internal astaxanthin can be effectively protected from being damaged by the external environment, and it is indicated that the double-protein nano-particles have potential application prospects in carrying of bioactive substances.

Description

Technical Field

[0001] The invention belongs to the field of functional foods and mainly relates to a preparation method of wheat alcohol-soluble protein / soybean protein isolate nanoparticles encapsulating astaxanthin. Background Art

[0002] Astaxanthin (ASTA), with the chemical name of 3, 3'-dihydroxy-4, 4'-diketo-β, β'-carotene, is a natural keto carotenoid found in marine organisms such as shrimp, crab, fish, and algae. Due to its long conjugated double bonds, unsaturated keto and hydroxyl structures, it has an active electronic effect, which gives ASTA stronger antioxidant activity than other carotenoids, but also makes ASTA susceptible to degradation by light, heat, acid, alkali, and oxygen. Therefore, constructing a suitable encapsulation system and improving the environmental stability and bioavailability of functional active substances have become the main challenges faced by the field of functional food research.

[0003] Gliadin (G) is the main storage protein of wheat. Based on its amphiphilicity and self-assembly ability, it has the ability to create micro / nanostructures to deliver bioactive substances. Due to its rich hydrophobic amino acids, wheat gliadin is insoluble in water but soluble in ethanol. This property makes wheat gliadin a suitable material for loading hydrophobic bioactive ingredients in delivery systems. However, the extremely high hydrophobicity of wheat gliadin makes the nanoparticles prepared from it unstable and easy to aggregate. In order to improve this shortcoming, combining wheat gliadin with hydrophilic substances has become an effective method. Soy protein isolate (SPI) is mainly composed of 7S and 11S globulins, of which about 57.8% of the amino acids are hydrophilic amino acids, which makes it have excellent solubility and hydrophilicity. At the same time, soy protein isolate is also a good carrier for the delivery of bioactive substances. In summary, SPI can be used to improve the stability of wheat gliadin nanoparticles and use it as a carrier of astaxanthin to enhance the environmental stability of astaxanthin.

[0004] This preparation method utilizes a pH-driven method to co-assemble wheat alcohol-soluble protein and soy protein isolate into nanoparticles, which greatly improves the stability of the nanoparticles and increases the astaxanthin encapsulation rate, laying the foundation for its further commercial application. Summary of the invention

[0005] The present invention aims to provide a method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles for embedding astaxanthin, which improves the stability of the protein nanoparticles and the embedding rate of astaxanthin.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented by the following technical solution: (1) weighing wheat alcohol-soluble protein and soy protein isolate according to different proportions; (2) dissolving samples of different proportions in distilled water; (3) stirring the mixed liquid at 600 r / min for 1 h; (4) subjecting the protein solution to ultrasonic dispersion treatment to promote the unfolding of its protein structure; (5) adding astaxanthin ethanol solution to the protein solution and stirring at 600 r / min for 1 h; (6) slowly adjusting the pH of the mixed system to 7.0 using 1M citric acid solution; (7) centrifuging the mixed system, taking the supernatant, and obtaining G / SPI nanoparticles and G / SPI / ASTA nanoparticles. Preferably, step (1) weighs wheat alcohol-soluble protein and soy protein isolate (total mass is 0.1 g) according to different proportions of 6:1, 3:1, 1:1, 1:3, 1:6, 1:8, and sets control samples GNPs and SNPs. Preferably, in step (2), samples of different proportions are dissolved in distilled water of pH 12. Preferably, in step (4), the protein solution is dispersed for 5 min under an ultrasonic power of 400 W to promote the unfolding of its protein structure. Preferably, in step (5), 0.5 mL of astaxanthin ethanol solution (2 mg / mL) is added to 10 mL of protein solution and stirred at 600 r / min for 1 h. Preferably, in step (7), the solution is centrifuged at 5000 rpm for 10 min and the supernatant is taken.

[0007] The present invention provides a method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles for embedding astaxanthin. The G / SPI nanoparticles prepared by the pH-driven method have a smaller particle size and a more excellent potential so that they can be stably dispersed in a solution, and the interaction between the wheat alcohol-soluble protein and the soybean protein isolate makes them have a more compact spatial structure. Subsequently, it is used for embedding astaxanthin, and it is found that the G / SPI nanoparticles greatly improve the embedding rate of astaxanthin, and it can be known from the thermal stability and light stability that the nanoparticles have excellent stability and can effectively protect astaxanthin. It shows that it has a wide range of application prospects in the field of bioactive substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Particle size of wheat prolamin / soy protein isolate nanoparticles with different ratios; Figure 2 Potential of wheat prolamin / soy protein isolate nanoparticles with different ratios; Figure 3 Astaxanthin encapsulation efficiency of wheat prolamin / soy protein isolate nanoparticles with different ratios; Figure 4Effect of heating on astaxanthin in wheat prolamin / soy protein isolate nanoparticles; Figure 5 Effect of light on astaxanthin in wheat prolamin / soy protein isolate nanoparticles; DETAILED DESCRIPTION

[0009] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0010] A method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles encapsulating astaxanthin comprises the following steps: (1) weighing wheat alcohol-soluble protein and soy protein isolate in different proportions; (2) dissolving samples in different proportions in distilled water; (3) stirring the mixed liquid at 600 r / min for 1 h; (4) subjecting the protein solution to ultrasonic dispersion treatment to promote the unfolding of its protein structure; (5) adding astaxanthin ethanol solution to the protein solution and stirring at 600 r / min for 1 h; (6) slowly adjusting the pH value of the mixed system to 7.0 using 1M citric acid solution; and (7) centrifuging the mixed system and taking the supernatant to obtain G / SPI nanoparticles and G / SPI / ASTA nanoparticles. Example

[0011] A method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles encapsulating astaxanthin comprises the following steps: in step (1), wheat alcohol-soluble protein and soy protein isolate (total mass of 0.1 g) are weighed in different ratios of 6:1, 3:1, 1:1, 1:3, 1:6, and 1:8, and control samples GNPs and SNPs are set; in step (2), samples of different ratios are dissolved in distilled water of pH 12; in step (3), the mixed liquid is stirred at 600 r / min for 1 h; in step (4), the protein solution is dispersed at an ultrasonic power of 400 W for 5 min to promote the unfolding of its protein structure; in step (5), 0.5 mL of astaxanthin ethanol solution (2 mg / mL) is added to 10 mL of the protein solution and stirred at 600 r / min for 1 h; in step (6), the pH of the mixed system is slowly adjusted to 7.0 using a 1 M citric acid solution; in step (7), the solution is centrifuged at 5000 rpm for 10 min, and the supernatant was taken to obtain G / SPI nanoparticles and G / SPI / ASTA nanoparticles. Finally, the particle sizes of G / SPI nanoparticles with different ratios were measured. The results are shown in Figure 1 shown.

[0012] Particle size test: The freshly prepared G / SPI nanoparticles were diluted 10 times with distilled water and then their particle size was measured by dynamic light scattering using a Zetasizer instrument. Example

[0013] A method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles encapsulating astaxanthin comprises the following steps: in step (1), wheat alcohol-soluble protein and soy protein isolate (total mass of 0.1 g) are weighed in different ratios of 6:1, 3:1, 1:1, 1:3, 1:6, and 1:8, and control samples GNPs and SNPs are set; in step (2), samples of different ratios are dissolved in distilled water of pH 12; in step (3), the mixed liquid is stirred at 600 r / min for 1 h; in step (4), the protein solution is dispersed at an ultrasonic power of 400 W for 5 min to promote the unfolding of its protein structure; in step (5), 0.5 mL of astaxanthin ethanol solution (2 mg / mL) is added to 10 mL of the protein solution and stirred at 600 r / min for 1 h; in step (6), the pH of the mixed system is slowly adjusted to 7.0 using a 1 M citric acid solution; in step (7), the solution is centrifuged at 5000 rpm for 10 min, and the supernatant was taken to obtain G / SPI nanoparticles and G / SPI / ASTA nanoparticles. Finally, the potential of G / SPI nanoparticles with different ratios was measured. The results are shown in Figure 2 shown.

[0014] Particle size test: The freshly prepared G / SPI nanoparticles were diluted 10 times with distilled water and their potential was tested by dynamic light scattering using a Zetasizer instrument. Example

[0015] A method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles encapsulating astaxanthin comprises the following steps: in step (1), wheat alcohol-soluble protein and soy protein isolate (total mass of 0.1 g) are weighed in different ratios of 6:1, 3:1, 1:1, 1:3, 1:6, and 1:8, and control samples GNPs and SNPs are set; in step (2), samples of different ratios are dissolved in distilled water of pH 12; in step (3), the mixed liquid is stirred at 600 r / min for 1 h; in step (4), the protein solution is dispersed at an ultrasonic power of 400 W for 5 min to promote the unfolding of its protein structure; in step (5), 0.5 mL of astaxanthin ethanol solution (2 mg / mL) is added to 10 mL of the protein solution and stirred at 600 r / min for 1 h; in step (6), the pH of the mixed system is slowly adjusted to 7.0 using a 1 M citric acid solution; in step (7), the solution is centrifuged at 5000 rpm for 10 min, and the supernatant was taken to obtain G / SPI nanoparticles and G / SPI / ASTA nanoparticles. Finally, the embedding rate of G / SPI / ASTA was measured. The results are as follows: Figure 3 shown.

[0016] Embedding rate: The sample was diluted 5 times with an organic solvent containing dichloromethane and methanol (2:1, v / v), vortexed for 1 min, centrifuged at 10,000 r / min for 20 min, and the supernatant was taken out and its absorbance was measured at 480 nm using a UV spectrophotometer, with a dichloromethane and methanol solution (2:1, v / v) as a blank. The embedding rate calculation formula is as follows: C n : The content of astaxanthin in the nanoparticles; C t : The content of astaxanthin initially added.

[0017] Example

[0018] A method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles encapsulating astaxanthin comprises the following steps: in step (1), wheat alcohol-soluble protein and soy protein isolate (total mass of 0.1 g) are weighed in different ratios of 6:1, 3:1, 1:1, 1:3, 1:6, and 1:8, and control samples GNPs and SNPs are set; in step (2), samples of different ratios are dissolved in distilled water of pH 12; in step (3), the mixed liquid is stirred at 600 r / min for 1 h; in step (4), the protein solution is dispersed at an ultrasonic power of 400 W for 5 min to promote the unfolding of its protein structure; in step (5), 0.5 mL of astaxanthin ethanol solution (2 mg / mL) is added to 10 mL of the protein solution and stirred at 600 r / min for 1 h; in step (6), the pH of the mixed system is slowly adjusted to 7.0 using a 1 M citric acid solution; in step (7), the solution is centrifuged at 5000 rpm for 10 min, and the supernatant was taken to obtain G / SPI nanoparticles and G / SPI / ASTA nanoparticles. Finally, 1:3 G / SPI nanoparticles were selected as carriers to measure the thermal stability of astaxanthin. The results are as follows Figure 4 shown.

[0019] Thermal stability test: G / SPI / ASTA nanoparticles and ASTA were heated at 60℃, 70℃, 80℃, and 90℃ for 30 min, and samples placed at room temperature of 25℃ for 30 min were used as controls. Subsequently, the retention rate of astaxanthin in the samples was determined. Example

[0020] A method for preparing wheat alcohol-soluble protein / soybean protein isolate nanoparticles encapsulating astaxanthin comprises the following steps: in step (1), wheat alcohol-soluble protein and soy protein isolate (total mass of 0.1 g) are weighed in different ratios of 6:1, 3:1, 1:1, 1:3, 1:6, and 1:8, and control samples GNPs and SNPs are set; in step (2), samples of different ratios are dissolved in distilled water of pH 12; in step (3), the mixed liquid is stirred at 600 r / min for 1 h; in step (4), the protein solution is dispersed at an ultrasonic power of 400 W for 5 min to promote the unfolding of its protein structure; in step (5), 0.5 mL of astaxanthin ethanol solution (2 mg / mL) is added to 10 mL of the protein solution and stirred at 600 r / min for 1 h; in step (6), the pH of the mixed system is slowly adjusted to 7.0 using a 1 M citric acid solution; in step (7), the solution is centrifuged at 5000 rpm for 10 min, and the supernatant was taken to obtain G / SPI nanoparticles and G / SPI / ASTA nanoparticles. Finally, 1:3 G / SPI nanoparticles were selected as carriers to measure the photostability of astaxanthin. The results are as follows Figure 5 shown.

[0021] Photostability test: G / SPI / ASTA nanoparticles and ASTA were placed at 25°C and 6 cm away from the UV lamp for 30 min, 60 min, 90 min, and 120 min. Then, the retention rate of astaxanthin in the sample was measured.

[0022] According to the experimental results attached to the specification, Figure 1 The average particle size of GNPs in the experiment was 383.27±8.91 nm. With the addition of SPI, the particle size gradually decreased. When the ratio was 1:3, the change of particle size tended to be stable at 189.90±5.75 nm, which indicated that SPI improved the particle size of GNPs. Figure 2 The potential diagram shows that GNPs have poor stability under neutral conditions and its potential is only -6.81±2.73 mV. As the proportion of SPI increases, its potential improves significantly. This is because SPI and Gliadin form a core-shell structure with Gliadin as the core and SPI as the shell during the pH-driven process. The outer layer of SPI provides Gliadin with sufficient charge so that it can be stably dispersed in the solution. It is applied to the loading of astaxanthin, such as Figure 3 As shown in the figure, the lowest embedding rate of GNPs is 28.51±5.75%. With the addition of SPI, the embedding rate shows an upward trend and reaches a maximum of 75.21±1.87% at 1:3, which greatly improves the embedding rate of astaxanthin. This is because SPI interacts with Gliadin to make the spatial structure more compact and prevent astaxanthin from escaping. 1:3 was selected as the optimal ratio. Figure 4 and Figure 5 It can be seen that G / SPI / ASTA nanoparticles have excellent thermal stability and light stability compared to free astaxanthin, and can effectively protect astaxanthin and prevent it from being damaged by external environmental factors. In summary, the G / SPI nanoparticles prepared by this manufacturing method greatly increase the embedding rate of astaxanthin and can effectively protect the internal astaxanthin from being damaged by the external environment.

[0023] Although the present invention has been disclosed as above in the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing wheat prolamin / soybean protein isolate nanoparticles encapsulating astaxanthin, characterized in that: The following steps are involved: (1) Weigh wheat alcohol-soluble protein and soy protein isolate in different proportions; (2) Dissolve samples in different proportions in distilled water; (3) Stir the mixed liquid at 600 r / min for 1 h; (4) Ultrasonic dispersion treatment is performed on the protein solution to promote the unfolding of its protein structure; (5) Astaxanthin ethanol solution is added to the protein solution and stirred at 600 r / min for 1 h; (6) The pH of the mixed system is slowly adjusted to 7.0 using 1 M citric acid solution; (7) The mixed system is centrifuged and the supernatant is taken to obtain G / SPI nanoparticles and G / SPI / ASTA nanoparticles.

2. The method for preparing wheat prolamin / soybean protein isolate nanoparticles encapsulating astaxanthin according to claim 1, characterized in that: Step (1) Wheat alcohol-soluble protein and soy protein isolate (total mass of 0.1 g) were weighed according to different ratios of 6:1, 3:1, 1:1, 1:3, 1:6, and 1:8, and control samples of GNPs and SNPs were set.

3. The method for preparing wheat prolamin / soybean protein isolate nanoparticles encapsulating astaxanthin according to claim 1, characterized in that: In step (2), samples of different proportions are dissolved in distilled water at pH 12.

4. The method for preparing wheat prolamin / soybean protein isolate nanoparticles encapsulating astaxanthin according to claim 1, characterized in that: In step (4), the protein solution is dispersed under an ultrasonic power of 400 W for 5 min to promote the unfolding of its protein structure.

5. The method for preparing wheat prolamin / soybean protein isolate nanoparticles encapsulating astaxanthin according to claim 1, characterized in that: In step (5), 0.5 mL of astaxanthin ethanol solution (2 mg / mL) was added to 10 mL of protein solution and stirred at 600 r / min for 1 h.

6. The method for preparing wheat prolamin / soy protein isolate nanoparticles encapsulating astaxanthin according to claim 1, characterized in that: In step (7), the solution was centrifuged at 5000 rpm for 10 min and the supernatant was collected.

7. The method for preparing wheat prolamin / soybean protein isolate nanoparticles encapsulating astaxanthin according to claim 1, characterized in that: The astaxanthin is successfully loaded by using wheat alcohol-soluble protein and soy protein isolate as raw materials through a pH-driven method. The obtained G / SPI nanoparticles greatly increase the astaxanthin encapsulation rate and can effectively protect the internal astaxanthin from being damaged by the external environment.

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