A static electrospinning embedded guava peel flavonoids sustained-release composite fiber membrane and a preparation method thereof

Abstract

A slow-release composite fiber membrane for encapsulating passion fruit peel flavonoids by electrospinning and its preparation method are disclosed. The composite fiber membrane is prepared by coaxial electrospinning and consists of a core layer and a shell layer. The core layer is a carrier solution containing passion fruit peel flavonoids, and the shell layer is a biodegradable polymer solution. The composite fiber membrane has an encapsulation rate of ≥85% for passion fruit peel flavonoids and possesses antioxidant and slow-release properties. Chitosan, gelatin, zein, and β-cyclodextrin are used as spinning wall materials, and passion fruit peel flavonoids extracted by DES method are used as the functional core material. Efficient encapsulation, controlled release, and stabilization of flavonoids are achieved through coaxial electrospinning. This invention solves the problems of easy oxidation, photothermal instability, poor water solubility, and low bioavailability of flavonoids.

Description

Technical Field

[0001] This invention relates to the field of sustained-release composite fiber membranes, and more particularly to a sustained-release composite fiber membrane for electrospinning and embedding flavonoids from passion fruit peel, and its preparation method. Background Technology

[0002] Passion fruit peel flavonoids possess strong antioxidant, anti-inflammatory, antibacterial, and free radical scavenging functions, but they face three major application bottlenecks: easy degradation and inactivation upon exposure to light, heat, and oxygen, resulting in poor stability; difficulty in dispersion in aqueous systems and poor solubility; and rapid release and uncontrollable burst release upon direct addition. Electrospinning can prepare nanoscale continuous fibers with large specific surface area, high porosity, and good biocompatibility, making them suitable for encapsulating, protecting, and controlling the release of natural active substances. Currently, there is no mature patented solution for encapsulating passion fruit peel flavonoids using coaxial electrospinning to form a biodegradable active packaging film. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention provides a method for preparing a slow-release composite fiber membrane for electrospun encapsulating flavonoids from passion fruit peel, characterized by simple processing, mild conditions, high encapsulation rate, strong stability, biodegradability, and edibility.

[0004] The objective of this invention is achieved through the following technical solution: A slow-release composite fiber membrane for encapsulating passion fruit peel flavonoids by electrospinning is disclosed. The composite fiber membrane is prepared by coaxial electrospinning and consists of a core layer and a shell layer. The core layer is a carrier solution containing passion fruit peel flavonoids, and the shell layer is a biodegradable polymer solution. The composite fiber membrane has an encapsulation rate of ≥85% for passion fruit peel flavonoids and exhibits antioxidant and slow-release properties of active substances.

[0005] The passion fruit peel flavonoids were obtained by DES extraction and macroporous resin purification, with a flavonoid purity of ≥50%.

[0006] The concentration of passion fruit flavonoids in the core layer solution is 50 mg / mL.

[0007] The biodegradable polymer constituting the shell is selected from any one or more of chitosan, gelatin, zein, β-cyclodextrin, pectin, and polyvinyl alcohol.

[0008] The volume ratio of the core solution to the shell solution ranges from 3:1 to 15:1, with a preferred ratio of 6:1.

[0009] A method for preparing a sustained-release composite fiber membrane containing flavonoids from passion fruit peel via electrospinning includes the following steps: S1. Passion fruit peel flavonoid concentrate was prepared by extracting passion fruit peel using the DES method and purifying it with macroporous resin to obtain passion fruit peel flavonoid concentrate with a purity ≥50%, which was then prepared into a core layer solution with a concentration of 50 mg / mL. S2 prepares the shell polymer solution by selecting a biodegradable polymer and using a corresponding solvent. The polymer mass-volume concentration is 6%-10%, preferably 8%. S3 mixing pretreatment involves mixing the core layer solution and the shell layer solution at a set volume ratio and magnetically stirring at 30°C for 1 hour to obtain the spinning precursor solution. S4 coaxial electrospinning uses a coaxial electrospinning device to spin, controlling the spinning voltage at 10-30kV, the receiving distance from the needle tip to the receiving plate at 9-21cm, and the spinning propulsion flow rate at 0.3-1.5mL / h. S5 Post-processing: Collect the spinning product and dry it to constant weight to obtain the slow-release composite fiber membrane. The optimal spinning process parameters in step S4 are: spinning voltage 26kV, receiving distance 14cm, and feed rate 1mL / h.

[0010] The shell polymer is zein, and 80% ethanol is used as the dissolving solvent.

[0011] The composite fiber membrane is used as an active food packaging film, an antioxidant coating, a wearable antibacterial material, or a carrier for health products.

[0012] Beneficial Effects: 1. This invention uses chitosan, gelatin, zein, and β-cyclodextrin as spinning wall materials, and passion fruit peel flavonoids extracted by DES method as functional core materials. Coaxial electrospinning achieves efficient encapsulation, controlled release, and stabilization of flavonoids. This invention solves the problems of easy oxidation, photothermal instability, poor water solubility, and low bioavailability of flavonoids. The resulting fiber membrane has a uniform diameter, no beads, and an encapsulation rate ≥85%. It possesses continuous antioxidant, biodegradable, and edible properties, and can be directly used in active food packaging films, antioxidant coatings, wearable antibacterial materials, and health product carriers. This invention achieves high encapsulation, high stability, and slow release of flavonoids, enabling industrial production.

[0013] 2. This invention employs a coaxial electrospinning structure, achieving an encapsulation rate of over 85% for flavonoids in passion fruit peel. This effectively enhances flavonoid stability and prevents degradation due to light, heat, and oxygen. It enables controlled, sustained release of flavonoids, solving the problem of rapid deactivation of active ingredients and providing long-lasting antioxidant and antibacterial effects. The use of biodegradable wall materials ensures the product is green, safe, edible, and pollution-free, with a wide range of applications. The preparation process is mild, with controllable parameters, simple to implement, and suitable for industrial production. Attached Figure Description

[0014] Figure 1This is a diagram showing the results of the wall material selection for this invention.

[0015] Figure 2 This is a graph showing the single-factor results of polymer concentration in this invention.

[0016] Figure 3 This is a graph showing the single-factor results of the wall-to-core ratio in this invention.

[0017] Figure 4 This is a graph showing the voltage single-factor results of the present invention.

[0018] Figure 5 This is a single-factor result diagram of the receiving distance of the present invention.

[0019] Figure 6 This is a graph showing the single-factor results of flow rate in this invention.

[0020] Figure 7 This is a diagram illustrating the interaction between distance and voltage in this invention.

[0021] Figure 8 This is a diagram illustrating the interaction between flow rate and voltage in this invention.

[0022] Figure 9 This is a diagram illustrating the interaction between flow velocity and distance in this invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments: Example 1: A method for preparing a sustained-release composite fiber membrane containing flavonoids from passion fruit peel via electrospinning includes the following steps: Preparation of flavonoids from passion fruit peel The flavonoid concentrate (purity ≥50%) was obtained by extraction using the DES method and purification using macroporous resin.

[0024] Spinning solution preparation Core layer solution: Take the flavonoid concentrate extracted from two DES solutions with a flavonoid concentration of 50 mg / mL for later use.

[0025] Shell fluid: 1. Gelatin: Weigh 0.8g of gelatin and add 10mL of deionized water.

[0026] 2. Zeat protein: Weigh 0.8g of zeat protein and dissolve it in 10mL of 80% ethanol.

[0027] 3. Chitosan: Weigh 0.8g of chitosan and dissolve it in 10mL of 1% acetic acid.

[0028] 4. β-Cyclodextrin: Weigh 0.4g of β-cyclodextrin and 0.4g of polyvinyl alcohol, and add 10mL of deionized water; 5. Pectin: Weigh 0.8g of pectin and add 10mL of deionized water.

[0029] Spinning solution: Mix the core material and wall material at a volume ratio of 1:10, and stir magnetically at 30°C for 1 hour before use.

[0030] The polymer concentration was fixed at 8%, core-to-wall ratio at 10%, voltage at 15 kV, receiving distance at 15 cm, and flow rate at 2.5 mL / h using an electrospinning machine. After spinning, the embedded material was collected, dried to constant weight, and dissolved in 10 mL of ethanol solution. The absorbance of 1 mL of the embedded material solution was measured at 510 nm to calculate the flavonoid concentration.

[0031] Encapsulation rate (EE%) = (W1 / W0) × 100% W0: Initial quality of new material added before electrospinning.

[0032] W1: The actual mass of the core material embedded inside the fiber after electrospinning.

[0033] Example 2: Single-factor experiment 1. Polymer concentration single factor step Fixed parameters: core-to-wall ratio 10%, voltage 15kV, receiving distance 15cm, flow rate 2mL / h.

[0034] Polymer concentrations were prepared at 6%, 7%, 8%, 9%, and 10% (w / v), and the flavonoid encapsulation rate was measured after electrospinning.

[0035] 2. Core-to-wall ratio (single factor) step Fixed parameters: polymer concentration 8%, voltage 15kV, receiving distance 15cm, flow rate 2mL / h.

[0036] The flavonoid encapsulation rate was measured after electrospinning with wall-to-core ratios of 3:1, 6:1, 9:1, 12:1, and 15:1.

[0037] 3. Single-factor electrospinning voltage step Fixed parameters: polymer concentration 8%, core-to-wall ratio 10%, receiving distance 15cm, flow rate 2mL / h.

[0038] The flavonoid encapsulation rate was measured after electrospinning at voltages of 10, 15, 20, 25, and 30 kV.

[0039] 4. Single factor for receiving distance (needle tip to collecting plate) step Fixed parameters: polymer concentration 8%, core-to-wall ratio 10%, voltage 15kV, flow rate 2mL / h.

[0040] The flavonoid encapsulation rate was measured after electrospinning at receiving distances of 9, 12, 15, 18, and 21 cm.

[0041] 5. Single factor of propulsion speed (flow velocity) step Fixed parameters: polymer concentration 8%, core-to-wall ratio 10%, voltage 15kV, receiving distance 15cm.

[0042] The flow rates were set to 0.3, 0.6, 0.9, 1.2, and 1.5 mL / h, and the flavonoid encapsulation rate was measured after electrospinning.

[0043] Example 3: Response surface methodology Using zein as the wall material and flavonoids extracted with choline chloride-ethylene glycol as the core material, a three-factor, three-level response surface methodology was developed based on the results of single-factor experiments, selecting spinning voltage, spinning distance, and spinning solution flow rate as the three factors.

[0044] Experimental results 1. Selection of wall material types Under the same extraction process conditions, zein showed the best encapsulation effect on passion fruit peel flavonoids among the eight wall materials. Zein was selected as the encapsulation wall material for extraction process optimization experiments. Figure 1 Wall material type selection results diagram 2. Single-factor experiments, such as Figures 2-6 As shown; Figure 2 Single-factor results of polymer concentration Figure 3 Single-factor results chart of core-wall ratio Figure 4 Voltage Single Factor Result Graph Figure 5 Single-factor result graph of receiving distance Figure 6 Single-factor results graph of flow velocity 3. Response surface methodology Response surface methodology (RSM) analysis revealed that this study used electrospinning technology to prepare zein-encapsulated passion fruit peel flavonoid nanofibers. By investigating the effects of voltage (A), receiving distance (B), and flow rate (C) on the encapsulation efficiency, the RSMs all exhibited a downward-opening convex paraboloid shape, indicating the existence of an optimal process extreme point within the experimental range. Voltage had the most significant impact on the encapsulation efficiency, exhibiting the steepest surface curvature. Low flow rate (approximately 1.0 mL / h) and a moderate receiving distance (approximately 15 cm) were beneficial for improving the encapsulation efficiency. A significant interaction existed between voltage and flow rate; the effect of voltage on improving the encapsulation efficiency was more pronounced at low flow rates, while the interactions between voltage and distance, and between distance and flow rate, were relatively insignificant.

[0045] Figure 7 Interaction diagram of distance and voltage Figure 8 Interaction diagram of flow rate and voltage Figure 9 Interaction diagram of flow velocity and distance The optimal combination of response surface methodology was verified. With the spinning voltage fixed at 26 kV, spinning distance at 14 cm, spinning solution flow rate at 1 mL / h, polymer concentration at 8%, and wall-to-core ratio at 6:1, three parallel experiments were conducted, and the flavonoid encapsulation rate was found to be 85.7%, which is close to the predicted value of 86.56%.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A slow-release composite fiber membrane for electrospun and encapsulating flavonoids from passion fruit peel, characterized in that, The composite fiber membrane is prepared by coaxial electrospinning and consists of a core layer and a shell layer. The core layer is a carrier solution containing passion fruit peel flavonoids, and the shell layer is a biodegradable polymer solution. The composite fiber membrane has a passion fruit peel flavonoid encapsulation rate of ≥85% and possesses antioxidant and active substance sustained-release properties.

2. The electrospun slow-release composite fiber membrane for encapsulating passion fruit peel flavonoids according to claim 1, characterized in that, The passion fruit peel flavonoids were obtained by DES extraction and macroporous resin purification, with a flavonoid purity of ≥50%.

3. The electrospun slow-release composite fiber membrane for encapsulating passion fruit peel flavonoids according to claim 1, characterized in that, The concentration of passion fruit flavonoids in the core layer solution is 50 mg / mL.

4. The electrospun slow-release composite fiber membrane for encapsulating passion fruit peel flavonoids according to claim 1, characterized in that, The biodegradable polymer constituting the shell is selected from any one or more of chitosan, gelatin, zein, β-cyclodextrin, pectin, and polyvinyl alcohol.

5. The electrospun slow-release composite fiber membrane for encapsulating passion fruit peel flavonoids according to claim 1, characterized in that, The volume ratio of the core solution to the shell solution ranges from 3:1 to 15:

1.

6. A method for preparing a sustained-release composite fiber membrane containing flavonoids from passion fruit peel via electrospinning, as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Passion fruit peel flavonoid concentrate was prepared by extracting passion fruit peel using the DES method and purifying it with macroporous resin to obtain passion fruit peel flavonoid concentrate with a purity ≥50%, which was then prepared into a core layer solution with a concentration of 50 mg / mL. S2 prepares the shell polymer solution by selecting a biodegradable polymer and using the corresponding solvent to prepare the shell polymer solution, with a polymer mass-volume concentration of 6%-10%; S3 mixing pretreatment involves mixing the core layer solution and the shell layer solution at a set volume ratio and magnetically stirring at 30°C for 1 hour to obtain the spinning precursor solution. S4 coaxial electrospinning uses a coaxial electrospinning device to spin, controlling the spinning voltage at 10-30kV, the receiving distance from the needle tip to the receiving plate at 9-21cm, and the spinning propulsion flow rate at 0.3-1.5mL / h. S5 Post-processing: Collect the spinning product and dry it to constant weight to obtain the slow-release composite fiber membrane.

7. The method for preparing a sustained-release composite fiber membrane of passion fruit peel flavonoids encapsulated by electrospinning according to claim 6, characterized in that, The optimal spinning process parameters in step S4 are: spinning voltage 26kV, receiving distance 14cm, and feed rate 1mL / h.

8. The method for preparing a sustained-release composite fiber membrane of passion fruit peel flavonoids encapsulated by electrospinning according to claim 6, characterized in that, The shell polymer is zein, and 80% ethanol is used as the dissolving solvent.

9. The application of the electrospun slow-release composite fiber membrane for encapsulating flavonoids from passion fruit peel according to claim 1, characterized in that, The composite fiber membrane is used as an active food packaging film, an antioxidant coating, a wearable antibacterial material, or a carrier for health products.

Images