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CN-122011841-A - Preparation method of hydrogel composite coating and application of hydrogel composite coating in fruit and vegetable fresh-keeping

CN122011841ACN 122011841 ACN122011841 ACN 122011841ACN-122011841-A

Abstract

The invention relates to the technical field of food science, and discloses a preparation method of a hydrogel composite coating and application of the hydrogel composite coating in fruit and vegetable fresh-keeping; the hydrogel composite coating takes chitosan as a base material, combines chlorogenic acid and zinc oxide nano particles derived from honeysuckle extract, has a multi-layer three-dimensional porous structure with a clear structure, has good structural stability and excellent biocompatibility, is used for fruit and vegetable fresh-keeping application, effectively reduces nutrition loss caused by oxidative spoilage, has a broad-spectrum inhibition effect on various food pathogens, is particularly suitable for perishable fruits and vegetables, accords with green packaging trend, and is biodegradable.

Inventors

  • QU LIANG
  • XU DI
  • Hua Lujing
  • WANG LUYA
  • ZHANG XINXIN
  • REN YAJIE

Assignees

  • 芜湖职业技术学院

Dates

Publication Date
20260512
Application Date
20260122

Claims (10)

  1. 1. The preparation method of the hydrogel composite coating is characterized by comprising the following steps of: S1, preparing zinc oxide nano particles, namely mixing bis (2, 4-pentanedione) zinc (II) serving as a zinc source and a polyethylene glycol aqueous solution with the molecular weight of 2000-10000 serving as a morphology regulator according to the mass volume ratio of the bis (2, 4-pentanedione) zinc (II) to the polyethylene glycol aqueous solution of 1 (10-15) to obtain a reaction mixed solution, magnetically stirring for 30min until the zinc oxide nano particles are completely dissolved, and then heating, refluxing, cooling and centrifugal purifying to obtain the zinc oxide nano particles; S2, preparing chlorogenic acid extract powder, namely soaking honeysuckle in pure water, performing enzymolysis with cellulase, performing hot water extraction, centrifuging and rotary evaporation drying to obtain the chlorogenic acid extract powder, wherein the enzymolysis condition is that the enzymolysis temperature is 50-60 ℃, the dosage of the cellulase is 0.1% of the dry weight of the honeysuckle, and the enzymolysis time is 1-2 hours; And S3, preparing a hydrogel composite coating, namely adding 30mg of chitosan into 0.1M acetic acid aqueous solution for dissolution, dropwise adding beta-sodium glycerophosphate aqueous solution with the mass-volume ratio of 50% into the chitosan solution according to the volume ratio of 9:1, simultaneously adding 100 mug of zinc oxide nano particles obtained in the step S1 and chlorogenic acid extract powder obtained in the step S2 containing 100 mug of chlorogenic acid, and incubating for 48 hours through a constant-temperature shaking table to obtain the hydrogel composite coating.
  2. 2. The method according to claim 1, wherein in the step S1, the molecular weight of the aqueous polyethylene glycol solution is 6000, and the heating reflux, cooling and centrifugal purification comprises: Heating the reaction mixture to 100 ℃, then preserving the heat for 30min to remove free moisture in the system, and then raising the temperature to 180-200 ℃ and keeping the temperature for 2 hours; Heating to 250-260 ℃ at the speed of 10 ℃ per minute, and refluxing for 1 hour; After removing the heat source, cooling to 80 ℃, dispersing the product in hexane/ethanol mixed solution with the volume ratio of 1:1, and centrifugally purifying for 15min-1h at 8000-10000 r/min.
  3. 3. The method according to claim 1, wherein in step S1, the obtained zinc oxide nanoparticles are particles obtained by sieving with a 100-mesh sieve.
  4. 4. The preparation method according to claim 1, wherein in step S2, the chlorogenic acid extract powder is obtained by soaking honeysuckle in pure water, enzymatic hydrolysis with cellulase, hot water extraction, centrifugation and rotary evaporation drying, and specifically comprises: Placing honeysuckle in a 50 ℃ oven for drying, cooling to room temperature, and crushing by using a multifunctional crusher to obtain honeysuckle powder; adding pure water into the honeysuckle powder according to the feed liquid ratio of 1:30 g/mL, soaking for 1h, adding cellulase accounting for 0.1% of the dry weight of the honeysuckle, and carrying out enzymolysis at 50-60 ℃ for 1-2 h; after enzymolysis, extracting the honeysuckle by adopting a hot water extraction method, wherein the extraction temperature and the extraction time are respectively set to 80-90 ℃ and 1.5-2.0 h; the extract was centrifuged at 15 min at a parameter of 4,000 r/min, and the supernatant was taken and dried by rotary evaporation.
  5. 5. The method according to claim 4, wherein in step S2, chlorogenic acid content in the chlorogenic acid extract powder is 80% -90%, the honeysuckle powder is particles obtained by sieving with a 40-mesh sieve, and enzyme activity of cellulase is 10 ten thousand U/g.
  6. 6. The method according to claim 1, wherein in step S3, 30mg of chitosan is added to 0.1M aqueous acetic acid solution for dissolution, specifically comprising: 30mg of chitosan was gradually added to 3mL of aqueous acetic acid solution, vortex mixing was continued to give a uniform suspension, transferred to a 5mL centrifuge tube, and left to stand overnight at 4℃after sealing to ensure complete dissolution of chitosan.
  7. 7. The preparation method according to claim 1, wherein in step S3, the aqueous solution of β -sodium glycerophosphate is added dropwise gently, and uniform dispersion is ensured by gentle swirling after adding zinc oxide nanoparticles and chlorogenic acid extract powder.
  8. 8. The method according to claim 1, wherein, in step S3, The incubation condition of the constant temperature shaking table is that the temperature is 37 ℃ and the rotating speed is 100r/min.
  9. 9. Use of the hydrogel composite coating prepared by the method of any one of claims 1-8 in fruit and vegetable fresh-keeping, comprising the following steps: (1) Cleaning fruits and vegetables with sterile water or sterilizing with sodium hypochlorite with volume ratio of 2%; (2) Naturally drying the cleaned or disinfected fruits and vegetables for 1-2 hours under the ventilation condition of room temperature, and removing free water on the surface; (3) Immersing the dried fruits and vegetables in the hydrogel composite coating for 1-5min to ensure that the surfaces are completely wrapped by the glue solution, taking out the fruits and vegetables, ventilating and draining at room temperature for 10-20min to form a uniform coating on the surfaces of the fruits and vegetables, and storing at 25+/-2 ℃.
  10. 10. A fruit and vegetable fresh-keeping method, characterized in that the hydrogel obtained by the preparation method according to any one of claims 1-8 conforms to a coating.

Description

Preparation method of hydrogel composite coating and application of hydrogel composite coating in fruit and vegetable fresh-keeping Technical Field The invention belongs to the technical field of food science, and particularly relates to a preparation method of a hydrogel composite coating and application of the hydrogel composite coating in fruit and vegetable fresh-keeping. Background Currently, about one third of the global annual wasted food is derived from spoilage and damage caused by microbial contamination or oxidation reactions during storage, transportation and distribution, which is particularly serious for perishable foods (e.g., fruits and vegetables), which generally have a short shelf life and are highly susceptible to accelerated deterioration due to external environmental factors such as temperature fluctuations, humidity changes, and the like. To reduce food waste and spoilage, various preservatives and preservation techniques have been developed. Conventional preservatives generally include oxidizing agents, reducing agents, acidifying agents, and flavoring agents. Although these substances slow down the spoilage process to some extent, there are often significant drawbacks in that prolonged use can lead to undesirable changes in the taste of the food product and in some cases also constitute a health risk to the consumer. In recent years, advances in food science open up a new way for food preservation techniques. Natural actives are gaining importance for their biocompatibility and safety and are increasingly being explored as alternatives to synthetic preservatives. Therefore, the development of the fruit and vegetable fresh-keeping method with natural active substance sources is an important solution for solving the current fruit and vegetable fresh-keeping problem. Disclosure of Invention The invention aims to provide a preparation method of a hydrogel composite coating and application of the hydrogel composite coating in fruit and vegetable fresh-keeping. The technical scheme adopted by the invention is as follows: According to a first aspect of an embodiment of the present invention, there is provided a method for preparing a hydrogel composite coating, including the steps of: s1, preparing zinc oxide nano particles, namely mixing bis (2, 4-pentanedione) zinc (II) serving as a zinc source and a polyethylene glycol aqueous solution with the molecular weight of 2000-10000 serving as a morphology regulator according to the mass volume ratio of the bis (2, 4-pentanedione) zinc (II) to the polyethylene glycol aqueous solution of 1 (10-15) to obtain a reaction mixed solution, magnetically stirring for 30min to complete solution, and then heating, refluxing, cooling and centrifugally purifying to obtain the zinc oxide nano particles; S2, preparing chlorogenic acid extract, namely soaking honeysuckle in pure water, performing enzymolysis on the honeysuckle by using cellulase, performing hot water extraction, centrifuging and rotary evaporation drying to obtain chlorogenic acid extract powder, wherein the enzymolysis condition is that the enzymolysis temperature is 50-60 ℃, the dosage of the cellulase is 0.1% of the dry weight of the honeysuckle, and the enzymolysis time is 1-2 hours; And S3, preparing a hydrogel composite coating, namely adding 30mg of chitosan into 0.1M acetic acid aqueous solution for dissolution, dropwise adding beta-sodium glycerophosphate aqueous solution with the mass-volume ratio of 50% into the chitosan solution according to the volume ratio of 9:1, simultaneously adding 100 mug of zinc oxide nano particles obtained in the step S1 and chlorogenic acid extract powder obtained in the step S2 containing 100 mug of chlorogenic acid, and incubating for 48 hours through a constant-temperature shaking table to obtain the hydrogel composite coating. Optionally, in step S1, the molecular weight of the polyethylene glycol aqueous solution is 6000, and the heating reflux, cooling and centrifugal purification include: Heating the reaction mixture to 100 ℃, followed by a subsequent rise to 180-200 ℃ and hold for 2 hours; Heating to 250-260 ℃ at the speed of 10 ℃ per minute, and refluxing for 1 hour; After removing the heat source, cooling to 80 ℃, dispersing the product in hexane/ethanol mixed solution with the volume ratio of 1:1, and centrifugally purifying for 15min-1h at 8000-10000 r/min. Optionally, in step S1, the obtained zinc oxide nanoparticles are particles obtained by sieving through a 100 mesh sieve. Optionally, in step S2, the chlorogenic acid extract powder is obtained by soaking flos Lonicerae in pure water, performing enzymolysis with cellulase, hot water leaching, centrifuging, and rotary evaporating to dry, and specifically comprises: Placing honeysuckle in a 50 ℃ oven for drying, cooling to room temperature, and crushing by using a multifunctional crusher to obtain honeysuckle powder; adding pure water into the honeysuckle powder according to the feed liquid