CN115339168B

CN115339168B - High-ductility multilayer edible antibacterial packaging film and preparation method thereof

Info

Publication number: CN115339168B
Application number: CN202210429246.5A
Authority: CN
Inventors: 章检明; 易华西; 陈娟; 刘大群; 刘玳瑶; 张程程
Original assignee: Zhejiang Academy of Agricultural Sciences; Ocean University of China
Current assignee: Zhejiang Academy of Agricultural Sciences; Ocean University of China
Priority date: 2022-04-22
Filing date: 2022-04-22
Publication date: 2023-06-06
Anticipated expiration: 2042-04-22
Also published as: CN115339168A

Abstract

The invention discloses a high-ductility multilayer edible antibacterial packaging film and a preparation method thereof. In the invention, nisin is additionally added as a bacteriostatic agent, and the substance has an inhibitory effect on gram-positive bacteria and is also a natural antibacterial peptide. The material combines with the antibacterial property of chitosan to achieve the synergistic effect, so that the material has good antibacterial activity and high elongation at break. And the raw material sources for preparing the nisin-coated gelatin-chitosan-corn starch three-layer film are wide, the cost is low, the operation is simple, and the film material is degradable and has no pollution to the environment.

Description

High-ductility multilayer edible antibacterial packaging film and preparation method thereof

Technical Field

The invention belongs to the technical field of food packaging materials, and particularly relates to a high-ductility multilayer edible antibacterial packaging film and a preparation method thereof.

Background

The traditional plastic preservative film is difficult to degrade in natural environment, so that the environmental pollution is huge, and the current problem is that the treatment of the plastic preservative film garbage. The edible food packaging film uses edible biological macromolecular substances (such as polysaccharide, protein, wax and the like) as main matrixes, and is assisted with edible plasticizers, reinforcing agents, cross-linking agents and the like, and through a certain treatment method, the film-forming agent molecules interact with each other, and a film with a certain tensile strength and compact structure is formed after drying. Compared with the common plastic preservative film, the edible preservative film has the advantages of natural degradation, no pollution to the environment and the like, and has good application prospect.

In addition, the food is extremely easy to be spoiled due to the influence of microorganism invasion and the like in the production, storage, transportation and sales processes, so that the nutritional value of the food is damaged, and serious threat is caused to the safety of consumers. The plastic preservative film lacks active antibacterial property, cannot actively protect the contents, and needs to be added with preservative articles. The edible food packaging film takes edible biological macromolecular substances (such as polysaccharide, protein, wax and the like) as a main matrix, and after antibacterial active substances are added, the antibacterial performance of the edible food packaging film is greatly improved, and compared with a common plastic preservative film, the edible food packaging film has better physical properties, can prevent the permeation and migration of moisture, has good antibacterial performance, can ensure the food safety, and can greatly improve the food safety problem existing in the film industry.

The patent document of Chinese patent publication No. CN113402747A discloses an edible packaging film with high mechanical strength, which is prepared by taking chitosan and carboxymethyl cellulose as film matrixes and adopting a multilayer composite film forming mode. Although the composite film has excellent mechanical property and antibacterial property, the elongation at break is lower and reaches 4.255% at the highest, the ductility is not very good, and the critical problem of high water solubility is not solved; is unfavorable for food fresh-keeping application.

The patent document with the Chinese patent publication number of CN107840981A discloses a sodium alginate-chitosan double-layer edible film which is formed by crosslinking and compounding a sodium alginate film and a chitosan film. The air permeability and the oxygen permeability of the obtained film are obviously reduced and the tensile property and the transparency are obviously improved through the synergistic promotion among the components. However, the film has high light transmittance, and the capability of blocking ultraviolet rays is not strong enough, and the elongation at break of the film is not high enough, so that the film is not beneficial to the preservation application of food packaging films.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a preparation method of a high-ductility multilayer edible antibacterial packaging film, which solves the current situations of high water solubility and poor ductility of the edible packaging film in the prior art.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

a method for preparing a high-ductility multi-layer edible antibacterial packaging film, which comprises the following steps:

preparing a chitosan membrane solution which contains a plasticizer and wraps nisin;

preparing corn starch film liquid containing plasticizer;

preparing gelatin film liquid containing plasticizer;

and respectively forming a gelatin film liquid and a corn starch film liquid into a gelatin film and a corn starch film, coating chitosan film liquid on the gelatin film to form a film, obtaining a gelatin-chitosan film, and finally spreading the corn starch film on the gelatin-chitosan film to obtain the multilayer edible antibacterial packaging film.

Chitosan, gelatin and corn starch are used as a green, nontoxic and harmless polymer material, and are widely used in the aspects of film materials, packaging materials and the like. The common chitosan, gelatin and corn starch blend film has high water solubility and poor extensibility and antibacterial property, and limits the practicability and application of the chitosan, gelatin and corn starch composite material. The tensile strength of the film can be improved by a three-layer film compounding method, and the water solubility is reduced. Compared with the common edible blending packaging film, the ductility and water solubility of the packaging film are greatly improved, the packaging film has good antibacterial performance, ensures the safety of food, and has wide market prospect in the application of the food packaging film neighborhood.

Preferably, the preparation of the chitosan membrane solution which contains the plasticizer and wraps the nisin comprises the following steps:

preparing chitosan acetic acid aqueous solution with the mass concentration of 0.8-1.2%, stirring for 50-70 minutes at 45-55 ℃ to fully dissolve, and obtaining mixed solution 1;

adding a plasticizer into the mixed solution 1, and stirring for 50-70 minutes at room temperature to obtain a mixed solution 4, wherein the addition amount of the plasticizer is 0.3-0.7% of the mass of the mixed solution 1;

adding nisin into the mixed solution 4, and stirring for 50-70 minutes at room temperature to obtain a mixed solution 7, wherein the adding amount of nisin is 0.025-0.1% of the mass of the mixed solution 4;

filtering the mixed solution 7, taking filtrate, standing, and defoaming to obtain the chitosan membrane solution which contains the plasticizer and wraps nisin.

Preferably, the preparation of the corn starch film liquid containing the plasticizer comprises the following steps:

preparing corn starch aqueous solution with mass concentration of 2-4%, stirring for 35-50 min at 65-85 ℃ and stirring for 25-35 min at 45-60 ℃ to fully dissolve to obtain mixed solution 2;

adding a plasticizer into the mixed solution 2, and stirring for 50-70 minutes at room temperature to obtain a mixed solution 5, wherein the addition amount of the plasticizer is 0.3-0.7% of the mass of the mixed solution 2;

filtering the mixed solution 5, taking filtrate, standing, and defoaming to obtain the corn starch membrane solution.

Preferably, the preparation of the plasticizer-containing gelatin film liquid comprises:

preparing gelatin aqueous solution with the mass concentration of 1-2%, stirring for 50-70 minutes at 45-60 ℃ to fully dissolve, and obtaining mixed solution 3;

adding a plasticizer into the mixed solution 3, and stirring for 50-70 minutes at room temperature to obtain a mixed solution 6, wherein the addition amount of the plasticizer is 0.3-0.7% of the mass of the mixed solution 3;

filtering the mixed solution 6, taking filtrate, standing, and defoaming to obtain the gelatin membrane solution.

Preferably, the plasticizer is glycerol.

Preferably, the defoamed corn starch film liquid is uniformly coated on a glass plate, and is put in a constant temperature and humidity box for drying for 8-12 hours by a solution casting method, and then is taken out, so that the corn starch film is obtained.

Preferably, the gelatin film liquid is uniformly coated on a glass plate, and is put in a constant temperature and humidity box for drying for 10-14 hours by a solution casting method, and then taken out, so that the gelatin film is obtained.

Preferably, the chitosan film liquid coated with nisin is uniformly coated on the gelatin film, and the gelatin-chitosan film is obtained by a solution casting method, drying in a constant temperature and humidity box for 10-14 hours and then taking out.

Preferably, the corn starch film is flatly paved on the gelatin-chitosan film, the gelatin-chitosan film is taken out after being pressed for 6 to 15 minutes, the film is uncovered, and the multilayer edible antibacterial packaging film is obtained after the corn starch film is placed in a fume hood for 20 to 40 minutes to volatilize residual solvents.

The invention also provides the multilayer edible antibacterial packaging film with high ductility, which is prepared by the preparation method.

Compared with the prior art, the invention has the beneficial effects that:

the invention prepares the multilayer film by using gelatin-chitosan-corn starch, and discovers that the three-layer film has obvious improvement on water solubility and ductility. In addition, nisin is additionally added as a bacteriostatic agent, and the material has a inhibitory effect on gram-positive bacteria and is also a natural antibacterial peptide. The material combines with the antibacterial property of chitosan to achieve the synergistic effect, so that the material has good antibacterial activity and high elongation at break, and a multilayer edible antibacterial packaging film with high ductility is prepared. And the raw material sources for preparing the nisin-coated gelatin-chitosan-corn starch three-layer film are wide, the cost is low, the operation is simple, and the film material is degradable and has no pollution to the environment.

The invention is further described below with reference to the drawings and specific embodiments.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a process flow diagram of the present invention.

FIG. 2 is an infrared spectrum of the films of examples 1 to 4. (a) Infrared spectra for the three-layer film of example 1 with 0% nisin concentration; (b) Infrared spectra for the three-layer film of example 2 with nisin concentration of 0.025%; (c) Infrared spectrum of three-layer film with nisin concentration of 0.05% in example 3; (d) The infrared spectrum of the three-layer film of example 4 with nisin concentration of 0.1%.

Fig. 3 is a graph of light transmittance of the three-layer films of examples 1 to 4. (a) Transmittance of the three-layer film having 0% nisin concentration in example 1; (b) Transmittance of the three-layer film of example 2 having a nisin concentration of 0.025%; (c) Transmittance of the three-layer film of example 3 having nisin concentration of 0.05%; (d) The transmittance of the three-layer film having a nisin concentration of 0.1% in example 4 was obtained.

FIG. 4 is a graph showing the bacteriostasis rate of the three-layer film in examples 1 to 4. (a) The bacteriostasis rate of the three-layer film with 0% nisin concentration in example 1; (b) The bacteriostatic rate for the three-layer film of example 2 with nisin concentration of 0.025%; (c) The bacteriostasis rate of the three-layer film with nisin concentration of 0.05% in example 3; (d) The bacteriostasis rate of the three-layer film with nisin concentration of 0.1% in example 4 was shown.

FIG. 5 is a scanning electron microscope image of the three-layer film in examples 1 to 4. A is a scanning electron microscope image of a three-layer film with 0% nisin concentration in example 1; b is a scanning electron micrograph of a three-layer film with a nisin concentration of 0.025% in example 2; c is a scanning electron microscope image of a three-layer film with nisin concentration of 0.05% in example 3; d is a scanning electron micrograph of a three-layer membrane with 0.1% nisin concentration in example 4.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

Referring to fig. 1, a method for preparing a high-ductility multi-layered edible packaging film is provided, comprising the steps of:

(1) Preparing 1% chitosan acetic acid aqueous solution by mass fraction, stirring for 1 hour at 50 ℃, and fully dissolving to obtain mixed solution 1.

(2) Preparing gelatin aqueous solution with mass concentration of 1%, stirring at 55 ℃ for 1 hour, and fully dissolving to obtain mixed solution 2.

(3) Preparing corn starch aqueous solution with the mass fraction of 1%, stirring for 45 minutes at 80 ℃, stirring for 30 minutes at 55 ℃, and fully dissolving to obtain mixed solution 3.

(4) Glycerin was added as a plasticizer to the mixed solution 1 to obtain a mixed solution 4, wherein the addition amount of the plasticizer was 0.5% by mass of the mixed solution 1.

(5) Glycerol was added to the mixed solution 2 as a plasticizer to obtain a mixed solution 5, wherein the addition amount of the plasticizer was 0.5% by mass of the mixed solution 2.

(6) Glycerol was added to the mixed solution 3 as a plasticizer to obtain a mixed solution 6, wherein the addition amount of the plasticizer was 0.5% by mass of the mixed solution 3.

(7) And (3) fully dissolving the mixed solutions obtained in the steps (4) (5) and (6) at room temperature, filtering, taking filtrate, standing for 10 minutes to remove foam, and respectively obtaining chitosan film solution, gelatin film solution and corn starch film solution.

(8) And uniformly coating the defoamed corn starch film liquid on a glass plate, and drying the coated corn starch film liquid in a constant temperature and humidity box for 10 hours and taking out the coated corn starch film liquid.

(9) And uniformly coating the defoamed gelatin film liquid on a glass plate, and taking out after being dried in a constant temperature and humidity box for 12 hours.

(10) Uniformly coating the defoaming chitosan film liquid on the gelatin film obtained in the step (9), and drying in a constant temperature and humidity box at 40 ℃ and 50% RH for 12 hours and taking out.

(11) And (3) uncovering the corn starch film formed in the step (8), spreading the corn starch film on the gelatin-chitosan film in the step (10), pressing for 10 minutes, and placing in a fume hood for 30 minutes to volatilize residual solvents, thus obtaining the high-ductility multilayer edible antibacterial packaging film.

Example 2

Referring to fig. 1, a method for preparing a high-ductility multi-layered edible antibacterial packaging film is provided, comprising the steps of:

(7) Nisin was added to the mixed solution 4, and stirred at room temperature for 1 hour to obtain a mixed solution 7, wherein the addition amount of nisin was 0.025% by mass of the mixed solution 4.

(8) And (3) fully dissolving the mixed solution obtained in the steps (5) (6) and (7) at room temperature, filtering, taking filtrate, standing for 10 minutes, defoaming, and respectively obtaining the nisin-coated chitosan membrane solution, gelatin membrane solution and corn starch membrane solution.

(9) And uniformly coating the defoamed corn starch film liquid on a glass plate, and drying the coated corn starch film liquid in a constant temperature and humidity box for 10 hours and taking out the coated corn starch film liquid.

(10) And uniformly coating the defoamed gelatin film liquid on a glass plate, and taking out after being dried in a constant temperature and humidity box for 12 hours.

(11) Uniformly coating the defoamed chitosan film liquid coated with nisin on the gelatin film obtained in the step (10), and drying the gelatin film in a constant temperature and humidity box at 40 ℃ and 50% RH for 12 hours and taking out the gelatin film.

(12) And (3) uncovering the corn starch film formed in the step (9), spreading the corn starch film on the gelatin-Ni chitosan film in the step (11), pressing for 10 minutes, and placing in a fume hood for 30 minutes to volatilize residual solvents, thus obtaining the high-ductility multilayer edible antibacterial packaging film.

Example 3

(7) Nisin was added to the mixed solution 4, and stirred at room temperature for 1 hour to obtain a mixed solution 7, wherein the addition amount of nisin was 0.05% by mass of the mixed solution 4.

Example 4

(7) Nisin was added to the mixed solution 4, and stirred at room temperature for 1 hour to obtain a mixed solution 7, wherein the addition amount of nisin was 0.1% by mass of the mixed solution 4.

The composite preservative film obtained in the above example was subjected to the following performance test, and the performance measurement results are shown in table 1.

Tensile strength, elongation at break, measured according to GB/T13022-1991;

water content, water solubility, GB/T462-2003;

the water vapor transmission coefficient is measured according to GB/T2679.2-2015;

infrared spectrum measurement, according to YBB 0026204-2015;

light transmittance is measured according to GB/T2410-2008;

the antibacterial property was measured according to QB-T2591-2003.

The parameters of the preservative films prepared in examples 1-4 above are shown in Table 1.

The obtained infrared spectrogram is shown in figure 1;

the resulting transmittance plot, see FIG. 3;

the resulting bacteriostatic rates are shown in figure 4;

the obtained scanning electron microscope image is shown in fig. 5.

TABLE 1

In conclusion, it can be seen that the addition of nisin to the film significantly improves the elongation at break of the film. Along with the increase of the content of the antibacterial agent, the antibacterial rate of the film is also obviously improved.

In addition, the film prepared by the invention has excellent water solubility, mechanical property and antibacterial property, the water solubility is as low as 25.68%, the elongation at break can reach 123%, and the film has important application value in the field of food packaging.

While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims

1. A method for preparing a high-ductility multi-layer edible antibacterial packaging film, which is characterized by comprising the following steps:

preparing corn starch film liquid containing plasticizer;

preparing gelatin film liquid containing plasticizer;

respectively forming a gelatin film liquid and a corn starch film liquid into a gelatin film and a corn starch film, coating a chitosan film liquid on the gelatin film to form a film to obtain a gelatin-chitosan film, and finally spreading the corn starch film on the gelatin-chitosan film to obtain a multilayer edible antibacterial packaging film;

the preparation of the chitosan membrane solution which contains the plasticizer and wraps nisin comprises the following steps:

preparing chitosan acetic acid aqueous solution with the mass concentration of 0.8-1.2%, and stirring for 50-70 minutes at the temperature of 45-55 ℃ to fully dissolve to obtain mixed solution 1;

filtering the mixed solution 7, taking filtrate, standing, and defoaming to obtain the chitosan membrane solution which contains the plasticizer and wraps nisin;

the preparation of the corn starch film liquid containing the plasticizer comprises the following steps:

preparing a corn starch aqueous solution with the mass concentration of 2-4%, stirring for 35-50 minutes at 65-85 ℃ and stirring for 25-35 minutes at 45-60 ℃ to fully dissolve, so as to obtain a mixed solution 2;

filtering the mixed solution 5, taking filtrate, standing, and defoaming to obtain the corn starch film solution containing the plasticizer;

the preparation of the gelatin film liquid containing the plasticizer comprises the following steps:

filtering the mixed solution 6, taking filtrate, standing, and defoaming to obtain the gelatin membrane solution containing the plasticizer;

the plasticizer is glycerol.

2. The method for preparing the high-ductility multilayer edible antibacterial packaging film according to claim 1, wherein the corn starch film liquid containing the plasticizer is uniformly coated on a glass plate, and is prepared by a solution casting method, and the corn starch film is obtained after the corn starch film liquid is dried in a constant temperature and humidity box for 8-12 hours.

3. The method for preparing the high-ductility multilayer edible antibacterial packaging film according to claim 1, wherein the gelatin film liquid containing the plasticizer is uniformly coated on a glass plate, and the gelatin film is obtained by a solution casting method, and is taken out after being dried in a constant temperature and humidity box for 10-14 hours.

4. The method for preparing the high-ductility multilayer edible antibacterial packaging film according to claim 1, wherein the chitosan film liquid which contains the plasticizer and wraps nisin is uniformly coated on the gelatin film, and the gelatin-chitosan film is obtained after the chitosan film liquid is dried in a constant temperature and humidity box for 10-14 hours by a solution casting method.

5. The method for preparing the high-ductility multilayer edible antibacterial packaging film according to claim 1, wherein the corn starch film is flatly laid on the gelatin-chitosan film, the gelatin-chitosan film is taken out after being pressed for 6-15 minutes, the film is uncovered, and the multilayer edible antibacterial packaging film is obtained after placing in a fume hood for 20-40 minutes to volatilize residual solvents.

6. A high-ductility multi-layer edible antibacterial packaging film prepared by the preparation method of any one of claims 1 to 5.