Non-covalently loaded soybean peptide-blueberry polyphenol popping bead as well as preparation and application thereof

Abstract

The invention relates to a soybean peptide-blueberry polyphenol compound based on non-covalent compounding, a functional popping bead for embedding the compound and a preparation method and application of the functional popping bead, and belongs to the technical field of food processing. Soybean peptide and blueberry polyphenol are physically blended in an ultrapure water solution system according to a specific mass ratio, the mixture is stirred and subjected to standing treatment, the compound which is good in oxidation resistance and uniform in dispersion is obtained, and the average particle size range is 150-600 nm. And further mixing the compound with sodium alginate, dropwise adding the mixture into a calcium lactate solution for cross-linking and curing, and preparing the blasting bead embedded with the compound through an ionic gel method. The obtained blasting bead is spherical, stable in structure and good in texture property. The compound provided by the invention and the popping beads thereof can be applied to beverages, liquid milk, yoghourt and nutritional or functional foods, and have the functions of improving oxidative stress and the like. The process conditions are mild, the raw materials are natural, safe and edible, and the method has good industrial popularization value.

Description

Non-covalently loaded soybean peptide-blueberry polyphenol popping beads and their preparation and application Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a method for constructing a non-covalent complex of soybean peptides and blueberry polyphenols, and the preparation of popping beads encapsulating the complex based on a sodium alginate-calcium lactate gel system. Background Technology

[0002] Oxidative stress has been proven to play a crucial role in the occurrence and development of various chronic diseases, such as cardiovascular and cerebrovascular diseases, diabetes, and neurodegenerative diseases. In recent years, natural antioxidants have received widespread attention in the field of functional foods and nutritional health research due to their high safety and low toxicity.

[0003] Blueberry polyphenols are rich in anthocyanins and phenolic acids, which have good free radical scavenging ability; soybean antioxidant peptides are derived from the hydrolysis of soybean protein and have both biological activity and nutritional value. However, blueberry polyphenols themselves have poor stability and are easily oxidized and degraded; while soybean peptides, due to the exposure of hydrophobic groups, often exhibit bitter taste and poor flavor, which limits their widespread application in functional foods (Liu Gongbo, Zhang Kaiyue, Ding Xinyu, et al. Research progress on soybean peptides and their debittering [J]. Agricultural Products Processing, 2020, (20): 84-88. DOI: 10.16693 / j.cnki.1671-9646(X). 2020.10.064.). Therefore, constructing a composite system with both high stability and synergistic antioxidant activity has become a key challenge in current functional food research.

[0004] Polyphenolic compounds contain multiple hydroxyl functional groups, which can form non-covalent complexes with peptide molecules through hydrogen bonding, hydrophobic interactions, and π-π stacking, thereby regulating their structural configuration and improving their physicochemical and sensory properties (Xiong Ying, Yu Lin, Bai Wenfu, et al. Comparison of quality characteristics, antioxidant capacity and polyphenol composition of different blueberry varieties [J]. Journal of Central South University of Forestry and Technology, 2022, 42(02):119-128.DOI:10.14067 / j.cnki.1673-923x.2022.02.013.). Therefore, developing a new strategy of synergistically compounding antioxidant soybean peptides with natural blueberry polyphenols is expected to simultaneously improve their stability, antioxidant performance and taste. However, there are few reports in the published literature on research schemes that synergistically construct complexes of soybean peptides and blueberry polyphenols and apply them to food encapsulation systems (such as popping boba).

[0005] Popping beads (also known as liquid-filled beads or liquid-encapsulated beads) are a new form of food encapsulation. With their good encapsulation performance, controllable release characteristics and rich sensory experience, they have been gradually applied in recent years to the protection of active ingredients, flavor release and product appearance optimization (Wang Yuhan, Duan Jiawen, Liu Fengyi, et al. Research and development of functional popping beads encapsulated with probiotics [J]. Food Industry, 2018, 39(12):100-103.). In the existing technology, popping beads usually use a variety of food colloid thickeners (such as carrageenan, pectin, sodium carboxymethyl cellulose, etc.) as the main core material matrix, and are formulated with flavorings or sweeteners to form sensory flavors. However, they generally have limitations such as lack of nutritional functional components, single taste and poor natural flavor, which make it difficult to meet the development needs of functional foods or high value-added beverages (He Ye, Guo Jianxing, Cao Keyuan, et al. Optimization of processing technology of water chestnut popping beads based on sodium alginate-pectin compound system [J]. Food Safety Guide, 2025, (08): 62-66+70. DOI: 10.16043 / j.cnki.cfs.2025.08.052.).

[0006] To address the aforementioned issues, this invention proposes a novel approach that non-covalently combines soybean peptides and blueberry polyphenols under specific conditions, and then uses sodium alginate and calcium lactate to construct a gel encapsulation system. This method not only significantly improves the flavor characteristics and stability of soybean peptides but also enhances the antioxidant stability and sensory acceptance of polyphenols under complex environments (such as changes in pH and ionic strength), demonstrating broad application prospects. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention aims to provide a soybean peptide-blueberry polyphenol complex with synergistic antioxidant function, popping beads, and their preparation method and application. These popping beads use the soybean peptide-blueberry polyphenol complex as the main core material. By constructing a stable encapsulation system, they exhibit good particle size distribution, full morphology, improved sensory flavor, and storage stability and antioxidant function under complex environments such as acid-base and ionic strength variations.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] This invention provides a soybean peptide-blueberry polyphenol complex with antioxidant activity, the complex comprising the following components:

[0010] Soybean peptides and blueberry polyphenols; preferably, the mass ratio of soybean peptides to blueberry polyphenols is 10:(1.25-10).

[0011] Preferably, the average particle size of the complex ranges from 150 to 600 nm, and it is characterized by small particle size, narrow distribution, and high system uniformity, resulting in significant flavor improvement and making it suitable for further encapsulation treatment.

[0012] This invention also provides a method for preparing a soybean peptide-blueberry polyphenol complex with antioxidant activity, comprising the following steps:

[0013] S1: Dissolve soybean peptides and blueberry polyphenol powder separately in distilled water to prepare corresponding solutions;

[0014] S2: Slowly add the soybean peptide solution to the blueberry polyphenol solution according to the mass ratio to obtain a mixed solution;

[0015] S3: Place the mixed solution in a shaking water bath in the dark to react and obtain the soybean peptide-blueberry polyphenol complex.

[0016] Preferably, the oscillation time in step S3 is 60–240 min; the oscillation speed in step S3 is 50–200 r / min; and the oscillation temperature in step S3 is 25–40 °C.

[0017] The present invention also provides a non-covalently loaded soybean peptide-blueberry polyphenol popping bead, comprising the following components: soybean peptide, blueberry polyphenol, and sodium alginate; preferably, the mass ratio of soybean peptide, blueberry polyphenol, and sodium alginate is 10:(1.25-10):(4-7).

[0018] This invention also provides a method for preparing the above-mentioned non-covalently loaded soybean peptide-blueberry polyphenol popping beads, comprising the following steps:

[0019] S1: Add sodium alginate to the soybean peptide-blueberry polyphenol complex and stir magnetically to form a gel system;

[0020] S2: Dissolve calcium lactate powder in 100 mL of deionized water and stir until completely dissolved to obtain a calcium lactate solution;

[0021] S3: The composite gel is dripped into the calcium lactate solution, allowed to stand and solidify to form spherical particles, filtered and washed twice with ultrapure water to obtain the popping bead product containing the soybean peptide-blueberry polyphenol complex.

[0022] Preferably, the calcium lactate solution in step S2 has a calcium lactate mass fraction of 1.5-6%.

[0023] Preferably, the curing time in step S3 is 2 to 5 minutes.

[0024] This invention also provides the application of the above-mentioned soybean peptide-blueberry polyphenol complex in the preparation of functional foods, nutritional health foods, and daily chemical products that improve oxidative stress effects.

[0025] This invention also provides the application of the above-mentioned popping boba products in beverages, liquid milk, yogurt, and nutritional or functional foods.

[0026] The beneficial effects of this invention are:

[0027] 1. The soybean peptide-blueberry polyphenol complex provided by the present invention has nanoscale particle size characteristics, with small average particle size and concentrated distribution, which significantly improves the ABTS free radical scavenging ability, ·OH hydroxyl free radical scavenging ability and iron reducing power, and has excellent antioxidant properties.

[0028] 2. The popping beads prepared by this invention have a full shape, which can effectively mask the bitterness and beany taste of soybean peptides. They are also rich in active polypeptides and blueberry polyphenols, and have excellent sensory flavor and physiological activity. They have excellent antioxidant function and good taste and texture, and are suitable for the development of functional foods, nutritional drinks and high value-added health products. Attached Figure Description

[0029] Figure 1 shows the particle size distribution results of Examples 1-5 and Comparative Examples 1-3 of the present invention.

[0030] Figure 2 shows the PDI index distribution results of Examples 1-5 and Comparative Examples 1-3 of the present invention.

[0031] Figure 3 shows the zeta potential distribution results of Examples 1-5 and Comparative Examples 1-3 of the present invention.

[0032] Figure 4. Results of ABTS free radical scavenging rate of soybean peptide-blueberry polyphenol complexes with different mass ratios and polyphenols of the same concentration.

[0033] Figure 5. Results of soybean peptide-blueberry polyphenol complexes with different mass ratios and ·OH radical scavenging rates of polyphenols at the same concentration.

[0034] Figure 6. Results of iron reducing power determination for soybean peptide-blueberry polyphenol complexes with different mass ratios and polyphenols of the same concentration.

[0035] Figure 7. Flowchart of the preparation of soybean peptide-blueberry polyphenol popping beads. Detailed Implementation

[0036] The specific implementation of the present invention will be further described below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. Steps not specifically described in detail can be implemented or understood by those skilled in the art based on existing technology; reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially; all concentrations mentioned herein are mass fractions.

[0037] I. Implementation Method

[0038] (I) Components and proportions of the soybean peptide-blueberry polyphenol complex

[0039] This invention provides a soybean peptide and blueberry polyphenol complex with synergistic antioxidant function, comprising the following components:

[0040] Soy peptides and blueberry polyphenols;

[0041] The mass ratio of soybean peptides to blueberry polyphenols is 10:(1.25-10).

[0042] (II) A method for preparing soybean peptides, comprising the following steps:

[0043] Take 10g of soy protein isolate powder and add 100mL of distilled water; add 1%–4% of a compound enzyme preparation (preferably 1% Bacillus subtilis alkaline protease, 1% neutral compound protease, and 0.02% flavor protease) based on the weight of the protein powder, and perform enzymatic hydrolysis for 2–6 hours (preferably 4 hours); after enzymatic hydrolysis, inactivate the enzyme in a boiling water bath for 5–20 minutes, preferably 10 minutes; centrifuge (7500–8500 r / min for 5–15 minutes, preferably 8000 r / min for 10 minutes); collect the supernatant; perform ultrafiltration using an ultrafiltration membrane with a molecular weight cutoff of 3000 Da to obtain the filtrate, which is the soy peptide solution.

[0044] (III) A method for preparing a soybean peptide-blueberry polyphenol complex with antioxidant activity, comprising the following steps:

[0045] S1. Dissolve soybean peptides and blueberry polyphenol powders in distilled water to prepare corresponding solutions;

[0046] S2. Mix soybean peptide solution and blueberry polyphenol solution at a mass ratio of 10:(1.25~10) to form soybean peptide-blueberry polyphenol mixed solution;

[0047] S3. Place the mixed solution in a shaking water bath to react in the dark to obtain the complex.

[0048] The preferred conditions are as follows:

[0049] The oscillation time in step S3 is 60 min to 240 min, preferably 180 min;

[0050] The oscillation speed in step S3 is 50 r / min to 200 r / min, preferably 120 r / min;

[0051] The oscillation temperature in step S3 is 25℃~40℃, preferably 28℃.

[0052] (iv) The components and proportions of a soybean peptide-blueberry polyphenol popping bead with antioxidant activity, characterized in that:

[0053] Popping beads contain the following ingredients: soybean peptides, blueberry polyphenols, and sodium alginate;

[0054] The mass ratio of the three components is 10:(1.25~10):(4~7), preferably 10:5:6.25;

[0055] The complex is the soybean peptide-blueberry polyphenol complex obtained by the above preparation method.

[0056] (V) A method for preparing soybean peptide-blueberry polyphenol popping beads with antioxidant activity, comprising the following steps:

[0057] S1: Weigh 100 mL of soybean peptide-blueberry polyphenol complex solution prepared at a mass ratio of 10:5 (refer to the above-mentioned Embodiments 3 and 4), add 1.50 g of sodium alginate powder, and stir magnetically until uniform to form soybean peptide-blueberry polyphenol complex gel.

[0058] S2: Dissolve calcium lactate powder in 100 mL of deionized water and stir until completely dissolved to prepare a calcium lactate aqueous solution;

[0059] S3: Inject the above gel droplets into the calcium lactate solution, let it stand to solidify, forming stable spherical popping beads, then filter and wash twice with ultrapure water to obtain the target popping beads.

[0060] In step S2, the calcium lactate aqueous solution has a calcium lactate mass fraction of 1.5-6%.

[0061] The curing time in step S3 is 2 to 5 minutes.

[0062] II. Effect Measurement

[0063] (1) Particle size determination of soybean peptide-blueberry polyphenol complex

[0064] The composite sample was diluted to an appropriate concentration and tested three times, with the average value taken. The particle size of the sample solution was measured using a Malvern Zetasizer 3000 at a test temperature of 25°C and a refractive index of 1.33. The test parameters included the average particle size (Z-Average Diameter) and the polydispersity index (PDI), which were used to characterize the particle size and its uniformity of distribution.

[0065] (2) Determination of the antioxidant capacity of soybean peptide-blueberry polyphenol complex

[0066] ABTS+ free radical scavenging. 7 mmol / L ABTS+ free radical solution: 7 mmol / L ABTS aqueous solution and 2.45 mmol / L potassium persulfate were mixed at a 1:1 (v / v) ratio and reacted at room temperature in the dark for 16 h. The solution was then diluted to OD734 nm = 0.70 ± 0.02 (PBS was used as the diluent). A 1 mg / mL sample solution was prepared from the complex sample. 20 μL of this solution was added to 200 μL of the diluted ABTS+ solution. After reacting in the dark for 6 min, the absorbance (A1) was measured at 734 nm. For the blank control group, distilled water was used instead of the ABTS+ free radical solution, and the absorbance (A2) was measured. For the control group, distilled water was used instead of the sample, and the absorbance (A0) was measured. Glutathione was used as the positive control. The scavenging rate was calculated using the following formula:

[0067]

[0068] •OH radical scavenging. 50 μL of sample solution, 50 μL of 8 mmol / L FeSO4, and 50 μL of 1% H2O2 were added sequentially to an ELISA plate. After standing for 10 min, 50 μL of 6 mmol / L salicylic acid-ethanol solution was added, and the plate was reacted at 37℃ in the dark for 30 min. An equal volume of distilled water was added instead of the sample to serve as the control group (A0). Distilled water was used instead of FeSO4, H2O2, and salicylic acid-ethanol solution to serve as the sample blank (A2). The absorbance was measured at 510 nm using an ELISA reader. The •OH radical scavenging activity of soybean peptide and polyphenol solutions of the same concentration was also measured.

[0069]

[0070] Total reducing power determination. Total reducing power is based on the reduction of Fe by the complex sample. 3+ to Fe 2+ The reducing power of the sample solution was determined. A suitable amount of sample solution was diluted. 200 μL of sample solution, 200 μL of phosphate buffer (0.2 M, pH 6.6), and 200 μL of 1% potassium ferricyanide solution were added to a 1.5 mL EP tube. After mixing thoroughly, the mixture was reacted in a 50°C water bath for 20 minutes. After the reaction, 200 μL of 10% trichloroacetic acid solution was quickly added to terminate the reaction, followed by centrifugation at 12,000 g for 10 minutes. 90 μL of supernatant, 90 μL of distilled water, and 10 μL of 0.1% ferric chloride solution were added to a 96-well plate and mixed thoroughly. The absorbance was measured at 700 nm using a microplate reader. The reducing power of soybean peptide and polyphenol solutions of the same concentration was also determined.

[0071] (3) Determination of the texture of popping beads

[0072] Place the popping bead sample on the texture analyzer platform. The probe model is 36R. The test mode is set to TPA test. The trigger force is 10g. The speed before the test is 2.0mm / s, the speed during the test is 1.0m / s, the speed after the test is 1.5mm / s, and the deformation is set to 40%. Record the hardness, elasticity, and chewiness of the popping bead.

[0073] All experiments were repeated at least three times. Results are expressed as mean ± standard deviation (mean ± SD). One-way ANOVA was used to analyze significance using SPSS Statistics software. Different lowercase letters indicate significant differences (p < 0.05).

[0074] The technical solutions provided by the present invention will be described in detail below with reference to embodiments and comparative examples, but they should not be construed as limiting the scope of protection of the present invention.

[0075] (1) Preparation of soybean peptide-blueberry polyphenol complex

[0076] Example 1

[0077] The mass ratio of soybean peptide to blueberry polyphenol in the system is 2:1. The specific implementation plan is as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 60 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixture at 120 r / min at 28 °C in the dark for 180 min. After thorough shaking, obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4 °C for testing.

[0078] Example 2

[0079] The mass ratio of soybean peptide to blueberry polyphenol in the system is 1:1. The specific implementation plan is as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 120 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixture at 120 r / min at 28 °C in the dark for 180 min. After thorough shaking, obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4 °C for testing.

[0080] Example 3

[0081] The mass ratio of soybean peptide to blueberry polyphenol in the system is 4:1. The specific implementation plan is as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 30 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixture at 120 r / min at 28 °C in the dark for 180 min. After thorough shaking, obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4 °C for testing.

[0082] Example 4

[0083] The mass ratio of soybean peptide to blueberry polyphenol in the system is 8:1. The specific implementation plan is as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 15 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixture at 120 r / min at 28 °C in the dark for 180 min. After thorough shaking, obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4 °C for testing.

[0084] Example 5

[0085] The mass ratio of soybean peptide to blueberry polyphenol in the system is 2:1. The specific implementation plan is as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 60 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixture at 120 r / min at 28 °C in the dark for 60 min. After thorough shaking, obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4 °C for testing.

[0086] Example 6

[0087] The mass ratio of soybean peptide to blueberry polyphenol in the system is 2:1. The specific implementation plan is as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 60 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixture at 50 r / min at 25 °C in the dark for 60 min. After thorough shaking, obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4 °C for testing.

[0088] Example 7

[0089] The mass ratio of soybean peptide to blueberry polyphenol in the system is 2:1. The specific implementation plan is as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 60 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixture at 200 r / min at 40 °C in the dark for 240 min. After thorough shaking, obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4 °C for testing.

[0090] Comparative Example 1

[0091] The difference between Comparative Example 1 and Example 1 lies in the different reaction temperatures, oscillation speeds, and oscillation times of the oscillation system. The specific implementation methods are as follows: Weigh 200 mg of soybean peptide powder and dissolve it in 1 mL of distilled water, mix well to obtain a soybean peptide solution, weigh 60 mg of blueberry polyphenol powder and dissolve it in 4.4 mL of distilled water, mix well to obtain a blueberry polyphenol solution, slowly inject 0.6 mL of soybean peptide solution into the blueberry polyphenol solution, and oscillate the mixed solution at 55°C at 40 r / min in the dark for 30 min, and thoroughly oscillate to obtain a soybean peptide-blueberry polyphenol complex solution, which is then stored at 4°C for testing.

[0092] Comparative Example 2

[0093] The difference between Comparative Example 2 and Example 1 is that the mass ratio of soybean peptide to blueberry polyphenol in the system is 2:0. The specific implementation method is as follows: Weigh 200mg of soybean peptide powder and dissolve it in 1mL of distilled water. Mix well to obtain a soybean peptide solution. Slowly inject 0.6mL of soybean peptide solution into 4.4mL of distilled water. Shake the mixed solution at 55℃ and 40r / min in the dark for 30min. Shake thoroughly to obtain a soybean peptide solution. Store at 4℃ for testing.

[0094] Comparative Example 3

[0095] The difference between Comparative Example 3 and Example 1 is that the mass ratio of soybean peptide to blueberry polyphenol in the system is 0:1. The specific implementation method is as follows: Weigh 200mg of soybean peptide powder and dissolve it in 1mL of distilled water. Mix well to obtain a soybean peptide solution. Weigh 60mg of blueberry polyphenol powder and dissolve it in 4.4mL of distilled water. Mix well to obtain a blueberry polyphenol solution. Slowly inject 0.6mL of soybean peptide solution into the blueberry polyphenol solution. Shake the mixed solution at 55℃ and 40r / min in the dark for 30min. Shake thoroughly to obtain a soybean peptide-blueberry polyphenol complex solution. Store at 4℃ for testing.

[0096] (2) Preparation of soybean peptide-blueberry polyphenol popping beads

[0097] Example 8

[0098] Prepare 100 mL of soybean peptide-blueberry polyphenol complex solution (Example 1). Add 1.50 g of sodium alginate powder according to the mass ratio of soybean peptide, blueberry polyphenol, and sodium alginate of 10:5:6.25, and mix evenly with magnetic stirring to obtain soybean peptide-blueberry polyphenol complex gel. Dissolve 1.5 g of calcium lactate powder in 100 mL of deionized water and stir thoroughly to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand for 2 min to solidify, forming stable spherical particles. Filter and wash twice with ultrapure water to obtain popping beads containing soybean peptide-polyphenol complex.

[0099] Example 9

[0100] Prepare 100 mL of soybean peptide-blueberry polyphenol complex solution (Example 1). Add 1.50 g of sodium alginate powder according to the mass ratio of soybean peptide, blueberry polyphenol, and sodium alginate of 10:5:6.25, and mix evenly with magnetic stirring to obtain soybean peptide-blueberry polyphenol complex gel. Dissolve 3.0 g of calcium lactate powder in 100 mL of deionized water and stir thoroughly to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand for 2 min to solidify, forming stable spherical particles. Filter and wash twice with ultrapure water to obtain popping beads containing soybean peptide-polyphenol complex.

[0101] Example 10

[0102] Prepare 100 mL of soybean peptide-blueberry polyphenol complex solution (Example 1). Add 0.96 g of sodium alginate powder according to the mass ratio of soybean peptide, blueberry polyphenol, and sodium alginate of 10:5:4, and mix evenly with magnetic stirring to obtain soybean peptide-blueberry polyphenol complex gel. Dissolve 6.0 g of calcium lactate powder in 100 mL of deionized water and stir thoroughly to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand for 2 min to solidify, forming stable spherical particles. Filter and wash twice with ultrapure water to obtain popping beads containing soybean peptide-polyphenol complex.

[0103] Example 11

[0104] Prepare 100 mL of soybean peptide-blueberry polyphenol complex solution (Example 1). Add 1.68 g of sodium alginate powder according to the mass ratio of soybean peptide, blueberry polyphenol, and sodium alginate of 10:5:7, and mix evenly with magnetic stirring to obtain soybean peptide-blueberry polyphenol complex gel. Dissolve 3.0 g of calcium lactate powder in 100 mL of deionized water and stir thoroughly to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand for 5 min to solidify, forming stable spherical particles. Filter and wash twice with ultrapure water to obtain popping beads containing soybean peptide-polyphenol complex.

[0105] Example 12

[0106] Prepare 100 mL of soybean peptide-blueberry polyphenol complex solution (Example 2). Add 1.68 g of sodium alginate powder according to the mass ratio of soybean peptide, blueberry polyphenol, and sodium alginate of 10:10:6.25, and mix evenly with magnetic stirring to obtain soybean peptide-blueberry polyphenol complex gel. Dissolve 3.0 g of calcium lactate powder in 100 mL of deionized water and stir thoroughly to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand for 2 min to solidify, forming stable spherical particles. Filter and wash twice with ultrapure water to obtain popping beads containing soybean peptide-polyphenol complex.

[0107] Example 13

[0108] Prepare 100 mL of soybean peptide-blueberry polyphenol complex solution (Example 4). Add 1.68 g of sodium alginate powder according to the mass ratio of soybean peptide, blueberry polyphenol, and sodium alginate of 10:1.25:7, and mix evenly with magnetic stirring to obtain soybean peptide-blueberry polyphenol complex gel. Dissolve 3.0 g of calcium lactate powder in 100 mL of deionized water and stir thoroughly to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand for 2 minutes to solidify, forming stable spherical particles. Filter and wash twice with ultrapure water to obtain popping beads containing soybean peptide-polyphenol complex.

[0109] Comparative Example 4

[0110] 1.50g of sodium alginate powder was added to 100mL of distilled water and magnetically stirred until homogeneous to obtain sodium alginate gel; 3.0g of calcium lactate powder was dissolved in 100mL of deionized water and stirred thoroughly until completely dissolved to obtain calcium lactate aqueous solution; soybean peptide-blueberry polyphenol complex gel was dripped into calcium lactate solution, allowed to stand and solidify for 2min to form stable spherical particles, filtered, and washed twice with ultrapure water to obtain sodium alginate popping beads.

[0111] Comparative Example 5

[0112] Prepare 100 mL of soybean peptide (Comparative Example 2) solution. Add 1.50 g of sodium alginate powder according to the mass ratio of soybean peptide to sodium alginate of 10:6.25, and mix evenly with magnetic stirring to obtain soybean peptide gel. Take 3.0 g of calcium lactate powder and dissolve it in 100 mL of deionized water. Stir thoroughly to completely dissolve it to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand and solidify for 2 min to form stable spherical particles, filter, and wash twice with ultrapure water to obtain soybean peptide popping beads.

[0113] Comparative Example 6

[0114] Prepare 100 mL of blueberry polyphenol (Comparative Example 3) solution. Add 1.50 g of sodium alginate powder according to the mass ratio of blueberry polyphenol to sodium alginate of 5:6.25, and mix evenly with magnetic stirring to obtain blueberry polyphenol gel. Take 3.0 g of calcium lactate powder and dissolve it in 100 mL of deionized water. Stir thoroughly to completely dissolve it to obtain calcium lactate aqueous solution. Drop the soybean peptide-blueberry polyphenol complex gel into the calcium lactate solution, let it stand and solidify for 2 min to form stable spherical particles, filter, and wash twice with ultrapure water to obtain blueberry polyphenol popping beads.

[0115] III. Experimental Results

[0116] Figure 1 shows the changes in particle size and multi-undispersibility index (PDI) of soybean peptides, blueberry polyphenols, and soybean peptide-blueberry polyphenol complexes. The blueberry polyphenol solution in Comparative Example 3 had the largest particle size, reaching 1040.15 ± 144.88 nm. After soybean peptides and blueberry polyphenols were compounded in appropriate proportions, the average particle sizes of the soybean peptide-blueberry polyphenol complexes in Examples 1-7 were 229.70 ± 69.47 nm, 256.40 ± 34.20 nm, 366.60 ± 53.98 nm, 375.90 ± 9.54 nm, and 388.68 ± 11.76 nm, respectively. The average particle size of the soybean peptide solution in Comparative Example 2 (403.403±31.68 nm) was lower than that of the blueberry polyphenol solution in Comparative Example 3, which had the largest particle size at 1040.15±144.88 nm. The particle size of the complex first decreased and then increased as the proportion of blueberry polyphenol added decreased. Similarly, as shown in Figure 2, consistent with the particle size distribution trend, the PDI index in the complex also first decreased and then increased as the proportion of blueberry polyphenol added decreased. When the ratio of soybean peptide to polyphenol was 2:1, it had the smallest particle size distribution and PDI index, indicating that its average particle size was low and the particle size distribution was narrow, indicating that it had high uniformity.

[0117] Figure 3 shows the potential changes of soybean peptides, blueberry polyphenols, and the soybean peptide-blueberry polyphenol complex. The potential of the complex is more stable than that of Comparative Examples 2 and 3. When the soybean peptide:blueberry polyphenol ratio is 8:1 to 1:1, the potential value of the complex in the examples is significantly increased compared with Comparative Examples 2 and 3 (p<0.05), indicating that soybean peptides and blueberry polyphenols interact at a specific ratio. Furthermore, the potential value is highest at a soybean peptide:blueberry polyphenol ratio of 2:1, suggesting that the interaction between the two may be strongest.

[0118] Furthermore, as shown in Figures 1, 2, and 3, the particle size distribution, PDI dispersion coefficient, and zeta absolute potential of Comparative Example 1 were 738.22±62.20 nm, 0.68±1.05, and 12.33±1.60, respectively. The particle size distribution was significantly larger than that of the soybean peptide-blueberry polyphenol complex in Example 1 (229.70±69.47 nm), the PDI dispersion coefficient was close to 0.7, and the zeta absolute potential was between that of the soybean peptide solution and the polyphenol solution. This indicates that the shaking time, shaking speed, and shaking temperature affect the interaction of the complex, suggesting that the system is unstable and may have insufficient reaction or no interaction reaction.

[0119] Figures 4-6 show the ABTS, ·OH radical, and ferric reducing power analyses of soybean peptides, blueberry polyphenols, and the soybean peptide-blueberry polyphenol complex, investigating the antioxidant activity of the soybean peptide-blueberry polyphenol complex. When the soybean peptide:blueberry polyphenol mass ratio was between 8:1 and 1:1 (Examples 1-4), the soybean peptide-blueberry polyphenol complex significantly improved the ABTS radical scavenging rate compared to soybean peptide (Comparative Example 2) alone, and was superior to the antioxidant capacity of polyphenols at the same concentration, indicating that the soybean peptide-blueberry polyphenol complex enhances the ABTS radical scavenging ability of soybean peptides. The trends in ·OH and ferric reducing power were similar to those of ABTS. When the soybean peptide-blueberry polyphenol ratio was between 8:1 and 1:1, the soybean peptide-blueberry polyphenol complex significantly improved the antioxidant capacity compared to soybean peptide (Comparative Example 2) alone, and was superior to the antioxidant capacity of polyphenols at the same concentration.

[0120] Table 1. Test results of various textural indicators of popping beads

[0121] Diameter (mm), Hardness (gf), Elasticity, Chewiness (gf), Example 8: 6.57 ± 0.13 a 572.88±27.59 ab 0.95±0.03 ab 467.33±52.71 a Example 96.52±0.65 a 546.37±57.96 ab 1.11±0.12 a458.30±75.52 a Example 106.46±0.49 a 576.37±62.24 ab 1.13±0.15 a 458.30±56.31 a Example 116.13±0.26 ab 651.04±49.82 ab 0.93±0.01 ab 401.47±42.47 ac Example 126.53±0.19 ab 586.59±10.20 ab 1.08±0.13 a 448.36±21.75 ab Example 136.11±0.10 a 622.78±10.16 ab 0.88±0.12 ab 315.92±8.80 bc Comparative Example 45.71 ± 0.41 ab 667.08±40.49 a 0.73±0.06 b 279.49±39.40 c Comparative Example: 56.00 ± 0.09 ab 664.01±49.41 ab 0.80±0.07 b 302.97±59.51 c Comparative Example: 65.35 ± 0.42 b 668.67±24.63 a 0.88±0.05 ab 331.36±52.20 ac surface

[0122] As shown in Table 1, the popping beads of the present invention have stable morphology, are spherical and uniform in size, and exhibit good performance in all aspects. The membrane diameter of the popping beads (Examples 8-13) encapsulated with soybean peptide-blueberry polyphenol complex of the present invention is approximately 6.11-6.57 gf, the hardness is between 546.37-651.04 gf, the elasticity is between 0.88-1.13, and the chewiness is between 315.92-458.30. The textural parameters indicate that the popping beads in the examples have moderate hardness and good elasticity, giving them a rich texture and variety. Compared with sodium alginate popping beads, soybean peptide popping beads, and blueberry polyphenol popping beads (Comparative Examples 4-6), they improve hardness, elasticity, and chewiness to a certain extent.

[0123] In summary, the beneficial effects of this invention are:

[0124] 1. The soybean peptide-blueberry polyphenol complex provided by the present invention has nanoscale particle size characteristics, with small average particle size and concentrated distribution, which significantly improves the ABTS free radical scavenging ability, ·OH hydroxyl free radical scavenging ability and iron reducing power, and has excellent antioxidant properties.

[0125] 2. The popping beads prepared by this invention have a full shape, which can effectively mask the bitterness and beany taste of soybean peptides. They are also rich in active polypeptides and blueberry polyphenols, and have excellent sensory flavor and physiological activity. They have excellent antioxidant function and good taste and texture, and are suitable for the development of functional foods, nutritional drinks and high value-added health products.

[0126] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A soybean peptide-blueberry polyphenol complex with antioxidant activity, characterized in that, The complex contains the following components: soybean peptides and blueberry polyphenols, wherein the mass ratio of soybean peptides to blueberry polyphenols is 10:(1.25-10).

2. The soybean peptide-blueberry polyphenol complex according to claim 1, characterized in that, The average particle size of the composite solution is 150–600 nm.

3. A method for preparing the soybean peptide-blueberry polyphenol complex with antioxidant activity as described in claim 1, characterized in that, Includes the following steps: S1. Dissolve soybean peptide powder and blueberry polyphenol powder in distilled water to obtain soybean peptide solution and blueberry polyphenol solution, respectively; S2. Slowly add the soybean peptide solution to the blueberry polyphenol solution according to the mass ratio to obtain a mixed solution; S3. The mixed solution is reacted in a shaking water bath under light-protected conditions to obtain a soybean peptide-blueberry polyphenol complex.

4. The preparation method according to claim 3, characterized in that, The oscillation time in step S3 is 60–240 min; the oscillation speed is 50–200 r / min; and the oscillation temperature is 25–40 °C.

5. A non-covalently loaded soybean peptide-blueberry polyphenol popping bead, characterized in that, It contains the following components: soybean peptides, blueberry polyphenols and sodium alginate, with a mass ratio of soybean peptides, blueberry polyphenols and sodium alginate of 10:(1.25-10):(4-7).

6. The method for preparing non-covalently loaded soybean peptide-blueberry polyphenol popping beads according to claim 5, characterized in that, The process includes the following steps: S1. Add sodium alginate to the soybean peptide-blueberry polyphenol complex solution and stir until a gel system is formed; S2. Prepare a calcium lactate solution by dissolving calcium lactate powder in deionized water and stirring thoroughly until completely dissolved; S3. Drop the gel system into the calcium lactate solution, allow it to stand and solidify to form spherical particles, filter and wash twice with ultrapure water to obtain popping beads containing the soybean peptide-blueberry polyphenol complex.

7. The preparation method according to claim 7, characterized in that, In step S2, the mass fraction of the calcium lactate solution is 1.5%–6%.

8. The preparation method according to claim 7, characterized in that, The curing time in step S3 is 2 to 5 minutes.

9. The use of the soybean peptide-blueberry polyphenol complex according to any one of claims 1-4 in the preparation of functional foods, nutritional health foods, and daily chemical products that improve oxidative stress effects.

10. The use of the soybean peptide-blueberry polyphenol popping beads according to any one of claims 5-8 in beverages, liquid milk, yogurt, nutritional or functional foods.

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