WHEAT GLUTEN NANOFIBER, METHOD FOR PREPARING THE SAME AND APPLICATION THEREOF

Abstract

The invention discloses a method for preparing wheat gluten nanofibers, which comprises steps of: (1) dissolving wheat gluten and glycerol monolaurate in a solvent to obtain a spinning solution; the solvent is an aqueous acetic acid solution; a volume percentage concentration of the aqueous acetic acid solution is 40-60%; in the spinning solution, a mass percentage concentration of wheat gluten is 20-30%; (2) carrying out electrospinning with the spinning solution to obtain wheat gluten nanofibers. The wheat gluten nanofibers of the present invention have water stability and antibacterial function, and are obtained by electrospinning with wheat gluten as a raw material, so the wheat gluten nanofibers have good biocompatibility and biodegradability.

Claims

1. A method for preparing wheat gluten nanofibers, comprising steps of: (1) dissolving wheat gluten and glycerol monolaurate in a solvent to obtain a spinning solution; wherein the solvent is an aqueous acetic acid solution; a volume percentage concentration of the aqueous acetic acid solution is 40-60%; in the spinning solution, a mass percentage concentration of wheat gluten is 20-30%; and (2) carrying out electrospinning with the spinning solution to obtain wheat gluten nanofibers.

2. The method for preparing wheat gluten nanofibers according to claim 1, wherein the glycerol monolaurate is added at an amount of 1-20% based on the mass of wheat gluten.

3. The method for preparing wheat gluten nanofibers according to claim 1, wherein in the step (2), the electrospinning is carried out with a voltage of 15-25 kV, a collecting distance of 10-15 cm, and a flow rate of 0.25-0.5 ml/h.

4. Wheat gluten nanofibers, wherein the wheat gluten nanofibers are prepared according to the method of claim 1.

5. A method of making food packaging material comprising the step of utilizing the wheat gluten nanofibers according to claim 4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is an SEM (scanning electron microscope) image of wheat gluten nanofibers prepared in Example 1;

[0027] FIG. 2 is an SEM image of wheat gluten nanofibers prepared in Example 1 after immersed in water for 7 days and then freeze-dried;

[0028] FIG. 3 is an SEM image of wheat gluten nanofibers prepared in Example 2;

[0029] FIG. 4 is an SEM image of wheat gluten nanofibers prepared in Example 2 after immersed in water for 7 days and then freeze-dried;

[0030] FIG. 5 is an SEM image of wheat gluten nanofibers prepared in Example 3;

[0031] FIG. 6 is an SEM image of wheat gluten nanofibers prepared in Example 3 after immersed in water for 7 days and then freeze-dried;

[0032] FIG. 7 is an SEM image of wheat gluten nanofibers prepared in Example 4;

[0033] FIG. 8 is an SEM image of wheat gluten nanofibers prepared in Example 4 after immersed in water for 7 days and then freeze-dried;

[0034] FIG. 9 is an SEM image of wheat gluten nanofibers prepared in Comparative Example 1;

[0035] FIG. 10 is an SEM image of wheat gluten nanofibers prepared in Comparative

[0036] Example 1 after immersed in water for 7 days and then freeze-dried.

DESCRIPTION OF THE EMBODIMENTS

EXAMPLE 1

[0037] 2.5 g of wheat gluten and 0.1 g of glycerol monolaurate were dissolved in 10 mL of a 50% aqueous acetic acid solution, and magnetically stirred until they were completely dissolved to obtain a homogeneous spinning solution.

[0038] The spinning solution obtained above was electrospun by using an electrospinning device with a 2.5 mL syringe having a 20 G steel needle under the conditions of a voltage of 15 kV, a flow rate of 0.5 mL/h, a collecting distance of 10 cm, and a rotating drum was used for collecting, thereby obtaining wheat gluten nanofibers marked as G4. The SEM image of G4 is shown in FIG. 1.

[0039] The obtained wheat gluten nanofibers were immersed in water at room temperature for 7 days, then taken out, freeze-dried and observed by SEM, as shown in FIG. 2. The obtained wheat gluten nanofiber was cut into 12 mm-diameter disks, which were pasted on plates coated with Staphylococcus aureus and Escherichia coli (concentration of bacterial solution, 10.sup.−8 CFU) respectively, and cultured at 37° C. for 24 hours. The antibacterial activity was evaluated by the size of the inhibition zone.

[0040] As shown in FIG. 1, the wheat gluten nanofibers obtained in Example 1 have an average diameter of 187.1 nm, with uniform morphology and free of beaded structures. After immersed in water for 7 days, the nanofibers swelled, but still maintained the fiber network morphology, as shown in FIG. 2.

EXAMPLE 2

[0041] 2.5 g of wheat gluten and 0.2 g of glycerol monolaurate were dissolved in 10 mL of a 50% aqueous acetic acid solution, and magnetically stirred until they were completely dissolved to obtain a homogeneous spinning solution.

[0042] The spinning solution obtained above was electrospun by using an electrospinning device with a 2.5 mL syringe having a 20 G steel needle under the conditions of a voltage of 15 kV, a flow rate of 0.5 mL/h, a collecting distance of 10 cm, and a rotating drum was used for collecting, thereby obtaining wheat gluten nanofibers marked as G8. The SEM image of G8 is shown in FIG. 3.

[0043] The obtained wheat gluten nanofibers were tested for their water stability (SEM image shown in FIG. 4) and antibacterial activity, with the steps being the same as those in Example 1.

[0044] As shown in FIG. 3, the wheat gluten nanofibers obtained in Example 2 have an average diameter of 149.0 nm, with uniform morphology and free of beaded structures. After immersed in water for 7 days, the nanofibers swelled, but still maintained the fiber network morphology, as shown in FIG. 4.

EXAMPLE 3

[0045] 2.5 g of wheat gluten and 0.3 g of glycerol monolaurate were dissolved in 10 mL of a 50% aqueous acetic acid solution, and magnetically stirred until they were completely dissolved to obtain a homogeneous spinning solution.

[0046] The spinning solution obtained above was electrospun by using an electrospinning device with a 2.5 mL syringe having a 20 G steel needle under the conditions of a voltage of 15 kV, a flow rate of 0.5 mL/h, a collecting distance of 10 cm, and a rotating drum was used for collecting, thereby obtaining wheat gluten nanofibers marked as G12. The SEM image of G12 is shown in FIG. 5.

[0047] The obtained wheat gluten nanofibers were tested for their water stability (SEM image shown in FIG. 6) and antibacterial activity, with the steps being the same as those in Example 1.

[0048] As shown in FIG. 5, the wheat gluten nanofibers obtained in Example 3 have an average diameter of 248.0 nm, with uniform morphology and free of beaded structures. After immersed in water for 7 days, the nanofibers swelled, but still maintained the fiber network morphology, as shown in FIG. 6.

EXAMPLE 4

[0049] 2.5 g of wheat gluten and 0.4 g of glycerol monolaurate were dissolved in 10 mL of a 50% aqueous acetic acid solution, and magnetically stirred until they were completely dissolved to obtain a homogeneous spinning solution.

[0050] The spinning solution obtained above was electrospun by using an electrospinning device with a 2.5 mL syringe having a 20 G steel needle under the conditions of a voltage of 15 kV, a flow rate of 0.5 mL/h, a collecting distance of 10 cm, and a rotating drum was used for collecting, thereby obtaining wheat gluten nanofibers marked as G16. The SEM image of G16 is shown in FIG. 7.

[0051] The obtained wheat gluten nanofibers were tested for their water stability (SEM image shown in FIG. 8) and antibacterial activity, with the steps being the same as those in Example 1.

[0052] As shown in FIG. 7, the wheat gluten nanofibers obtained in Example 4 have an average diameter of 270.8 nm, with uniform morphology and free of beaded structures. After immersed in water for 7 days, the nanofibers swelled, but still maintained the fiber network morphology, as shown in FIG. 8.

Comparative Example 1

[0053] 2.5 g of wheat gluten was dissolved in 10 mL of a 50% aqueous acetic acid solution, and magnetically stirred until they were completely dissolved to obtain a homogeneous spinning solution.

[0054] The spinning solution obtained above was electrospun by using an electrospinning device with a 2.5 mL syringe having a 20 G steel needle under the conditions of a voltage of 15 kV, a flow rate of 0.5 mL/h, a collecting distance of 10 cm, and a rotating drum was used for collecting, thereby obtaining wheat gluten nanofibers without glycerol monolaurate marked as G0. The SEM image of G0 is shown in FIG. 9.

[0055] The obtained wheat gluten nanofibers were tested for water stability (SEM image shown in FIG. 10) and antibacterial activity, with the steps being the same as those in Example 1.

[0056] As shown in FIG. 9, the wheat gluten nanofibers obtained in Comparative Example 1 have an average diameter of 310.7 nm, with uneven morphology and beaded structures. After immersed in water for 7 days, the morphology of the nanofibers completely disintegrated and disappeared, as shown in FIG. 10.

[0057] Evaluation of antibacterial efficacies of the wheat gluten nanofibers prepared in

[0058] Examples 1, 2, 3 and 4 and Comparative Example 1 against Staphylococcus aureus and Escherichia coli is shown in Table 1.

TABLE-US-00001 TABLE 1 Bacteria inhibition zone diameter (mm) Staphylococcus Sample Escherichia coli aureus G0 0 0 G4 13.0 ± 0.65.sup.c 17.5 ± 0.91.sup.d G8 15.5 ± 0.93.sup.b 19.5 ± 1.51.sup.c G12 15.7 ± 0.81.sup.b 22.0 ± 2.42.sup.b G16 18.5 ± 1.51.sup.a 25.0 ± 2.12.sup.a Note: The superscript letters (a, b, c and d) represent significant difference with p < 0.05.

[0059] As shown in Table 1, the wheat gluten nanofibers obtained in Comparative Example 1 have no antibacterial efficacy, but the wheat gluten nanofibers obtained in Examples 1, 2, 3 and 4 have inhibitory effects against Escherichia coli and Staphylococcus aureus. Moreover, with the increasing glycerol monolaurate content, the inhibition zone diameter of the nanofibers gradually increases, that is, the antibacterial efficacy increases significantly.

[0060] The above-mentioned embodiments have explained the technical solution and beneficial effects of the present invention in detail. It should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not used to limit the present invention. Any modifications, supplements and equivalent substitutions made within the principle of the present invention should be included in the protection scope of the present invention.