CN-121975438-A - Silk fibroin composite spray coating and preparation method and application thereof

CN121975438ACN 121975438 ACN121975438 ACN 121975438ACN-121975438-A

Abstract

The invention relates to the technical field of food fresh-keeping materials, in particular to a silk fibroin composite spray coating, a preparation method and application thereof, wherein solution A is silk fibroin solution, solution B is mixed solution of epsilon-polylysine and gamma-polyglutamic acid, solution A and solution B are respectively filled into two liquid storage cavities of a double-liquid spray coating system, spraying operation is carried out on the surfaces of fruits, and solution A and solution B are instantly mixed at a nozzle and sprayed on the surfaces of the fruits, so that a uniform and transparent fibrous composite coating film can be obtained without any subsequent drying or chemical treatment. Has the characteristics of quick film forming, multifunctional integration, washability and the like. The preparation process is simple and green, no organic solvent or post-treatment is needed, the material has excellent biocompatibility and degradability, and the problems that the edible coating in the prior art has long film forming time, requires organic solvent or post-treatment, and is difficult to integrate and remove multifunctional components are solved.

Inventors

XIAO WENQIAN
XIAO WENQIAN
SUN XINHE
ZHOU HANG
YU SIJIA
LI BO

Assignees

重庆科技大学

Dates

Publication Date: 20260505
Application Date: 20260209

Claims (10)

1. The preparation method of the silk fibroin composite spray coating is characterized by comprising the following steps of: Dissolving silk fibroin in deionized water or a buffer solution, and regulating pH to be neutral to obtain a silk fibroin solution; dissolving epsilon-polylysine and gamma-polyglutamic acid in deionized water to obtain epsilon-polylysine/gamma-polyglutamic acid mixed solution; Respectively filling the silk fibroin solution and the epsilon-polylysine/gamma-polyglutamic acid mixed solution into two liquid storage cavities of a double-liquid spraying system, and enabling the mixing volume ratio of the silk fibroin solution to the epsilon-polylysine/gamma-polyglutamic acid mixed solution to be 1:1; and spraying the surface of the fruit to be treated by using the double-liquid spraying system, so that the silk fibroin solution and the epsilon-polylysine/gamma-polyglutamic acid mixed solution are instantly mixed at a Y-shaped nozzle of the double-liquid spraying system and sprayed on the surface of the fruit to form a uniform and transparent fibrous composite coating film.
2. The method for preparing the silk fibroin composite spray coating according to claim 1, wherein the silk fibroin is dissolved in deionized water or a buffer solution, and the pH is adjusted to be neutral, so that the silk fibroin solution is obtained, and the method specifically comprises the following steps: The mass concentration of the silk fibroin solution is 3.8wt% and the pH is 6.5-7.5.
3. The method for preparing the silk fibroin composite spray coating according to claim 2, wherein the silk fibroin is dissolved in deionized water or a buffer solution, and the pH is adjusted to be neutral, so as to obtain a silk fibroin solution, and the method specifically comprises the following steps: cutting degummed silk into small sections, weighing a proper amount of degummed silk, adding the degummed silk into lithium bromide solution, and dissolving in a 60 ℃ incubator for 3-4 hours until the degummed silk is clear and transparent; Putting the obtained solution into a dialysis bag with the molecular weight cut-off of 3500Da, and dialyzing in deionized water for 3-4 days; After the dialysis was completed, the silk fibroin solution was concentrated to a mass concentration of 3.8wt% by polyethylene glycol concentration and stored at 4 ℃ for later use.
4. The method for preparing the silk fibroin composite spray coating according to claim 1, wherein the epsilon-polylysine and gamma-polyglutamic acid are dissolved in deionized water to obtain epsilon-polylysine/gamma-polyglutamic acid mixed solution, and the method specifically comprises the following steps: the mass concentration of epsilon-polylysine is 0.1-2wt%, the mass concentration of gamma-polyglutamic acid is 15-20wt%, and the pH value of epsilon-polylysine/gamma-polyglutamic acid mixed solution is 4.0-6.0.
5. The method for preparing the silk fibroin composite spray coating according to claim 4, wherein the epsilon-polylysine and gamma-polyglutamic acid are dissolved in deionized water to obtain epsilon-polylysine/gamma-polyglutamic acid mixed solution, and the method specifically comprises the following steps: Weighing a proper amount of gamma-polyglutamic acid powder, and dissolving the gamma-polyglutamic acid powder in deionized water to prepare a gamma-polyglutamic acid solution with the mass concentration of 15 wt%; Gradually adding epsilon-polylysine powder into the gamma-polyglutamic acid solution under continuous stirring to ensure that the mass concentration of epsilon-polylysine in the final mixed solution reaches 0.5wt%; vortex mixing to obtain epsilon-polylysine/gamma-polyglutamic acid mixed solution, and storing at room temperature for standby.
6. The method for preparing the silk fibroin composite spray coating according to claim 1, wherein the spraying of the surface of the fruit to be treated by the two-liquid spraying system comprises the following steps: the diameter of the nozzle of the double-liquid spraying system is 0.5mm, the spraying distance is 10-30cm, and the spraying time is 5-30 seconds.
7. The method for preparing the silk fibroin composite spray coating according to claim 1, wherein the silk fibroin is dissolved in deionized water or a buffer solution, and the pH is adjusted to be neutral, so that the silk fibroin solution is obtained, and the method specifically comprises the following steps: the silk fibroin is regenerated silk fibroin prepared by degumming, dissolving, dialyzing and concentrating silkworm silk.
8. The method for preparing the silk fibroin composite spray coating according to claim 1, wherein the epsilon-polylysine and gamma-polyglutamic acid are dissolved in deionized water to obtain epsilon-polylysine/gamma-polyglutamic acid mixed solution, and the method specifically comprises the following steps: the molecular weight of epsilon-polylysine is 2500-4500Da, and the molecular weight of gamma-polyglutamic acid is 50000-100000Da.
9. A silk fibroin composite spray coating prepared by the method for preparing a silk fibroin composite spray coating according to claim 1, wherein the coating is a film with a fibrous network structure in which silk fibroin exists in a beta-sheet conformation, gamma-polyglutamic acid and epsilon-polylysine are uniformly dispersed therein, and the thickness of the coating is 5-20 μm.
10. Use of the silk fibroin composite spray coating of claim 9 in fruit preservation.

Description

Silk fibroin composite spray coating and preparation method and application thereof Technical Field The invention relates to the technical field of food fresh-keeping materials, in particular to a silk fibroin composite spray coating, a preparation method and application thereof. Background The loss of the fruits and vegetables caused by water loss and microorganism infection is huge. The edible coating technology plays an important role in preserving fruits and vegetables after picking, and can reduce water loss and inhibit microorganism growth by forming a protective film on the surface. However, the traditional edible coating has the limitations of long film forming time, organic solvent treatment, single function, complex process and the like, and is difficult to meet the high-efficiency, green and safe industrialized fresh-keeping requirements. To overcome the above limitations, silk fibroin-based coating techniques have been widely studied for their excellent film forming properties, biocompatibility and degradability. For example, CN202110152222.5 discloses a preservation method of coating by using uncrosslinked silk fibroin solution, which avoids the use of chemical crosslinking agent and is simple to operate. In the second prior art, CN202210865750.X adopts glutamine transaminase and tyrosinase as cross-linking agents, and the stability and the barrier property of the coating are enhanced by enzymatic cross-linking. In the prior art, CN202410107821.9 proposes that chitosan and silk fibroin are compounded, and a template structure is constructed by utilizing metal ion chelation and eutectic solvent so as to integrate various functional components. The fourth prior art is that the CN202311500368.X relates to a composite edible film liquid containing silk fibroin, and the film liquid is coated by preparing microemulsion. In the prior art, CN202411585424.9 adopts an electrostatic spinning technology to prepare a silk fibroin-based nanofiber membrane so as to obtain a denser fiber network structure. However, these prior art techniques still have significant drawbacks. The uncrosslinked silk fibroin coating is insufficient in barrier property and requires long drying (1-5 hours) after coating. The enzyme crosslinking reaction and the subsequent treatment of the second technology take up to several hours, and the reaction conditions are harsh and difficult to control accurately. The third technique needs to stir in high-temperature oil bath for a long time (4 hours), has high energy consumption, and the low concentration of silk fibroin leads to insufficient film forming performance. The film forming of the fourth technology relies on solvent volatilization, is greatly influenced by environment, and the microemulsion preparation requires a surfactant, so that the technology is complex. In the fifth technique, although nanofibers can be formed, formic acid with strong corrosiveness and potential safety hazard of food is used as a solvent, and the electrostatic spinning process takes a long time, and the equipment is expensive and cannot be directly operated on the surfaces of fruits and vegetables. In summary, the prior art generally has the problems of low film forming efficiency, organic solvent requirement or complex post-treatment, complex process, difficult function integration and the like, and limits the practical application of the film in fruit and vegetable fresh-keeping. Disclosure of Invention The invention aims to provide a silk fibroin composite spray coating, a preparation method and application thereof, and solves the problems that the existing edible coating is long in film forming time, requires an organic solvent or complex post-treatment, is complex in process and is difficult to integrate with multiple functions. In order to achieve the above purpose, the invention provides a preparation method of a silk fibroin composite spray coating, which comprises the following steps: Dissolving silk fibroin in deionized water or a buffer solution, and regulating pH to be neutral to obtain a silk fibroin solution; dissolving epsilon-polylysine and gamma-polyglutamic acid in deionized water to obtain epsilon-polylysine/gamma-polyglutamic acid mixed solution; Respectively filling the silk fibroin solution and the epsilon-polylysine/gamma-polyglutamic acid mixed solution into two liquid storage cavities of a double-liquid spraying system, and enabling the mixing volume ratio of the silk fibroin solution to the epsilon-polylysine/gamma-polyglutamic acid mixed solution to be 1:1; and spraying the surface of the fruit to be treated by using the double-liquid spraying system, so that the silk fibroin solution and the epsilon-polylysine/gamma-polyglutamic acid mixed solution are instantly mixed at a Y-shaped nozzle of the double-liquid spraying system and sprayed on the surface of the fruit to form a uniform and transparent fibrous composite coating film. The method comprises the steps of dissolving silk