A fresh-keeping gasket capable of releasing CO2 in package and application thereof
By preparing a self-releasing CO2 preservation pad, the problem of spoilage caused by environmental instability in the cold chain transportation of fruits and vegetables is solved, achieving efficient preservation, extending the shelf life of fruits and vegetables, and possessing green safety and antibacterial effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NINGXIA UNIVERSITY
- Filing Date
- 2024-11-29
- Publication Date
- 2026-05-29
Smart Images
Figure CN122103647A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fruit and vegetable preservation, and relates to the processing technology of fruit and vegetable preservation pads, especially a preservation pad that can release CO2 within the packaging and its preparation method. Background Technology
[0002] China is the world's largest producer of fruits and vegetables, and also the country with the largest volume of fresh produce logistics and transportation. Because fruits and vegetables continue to undergo cellular respiration and metabolism after harvest, they consume nutrients such as sugars, reducing their market quality and leading to the release of endogenous ethylene, thus accelerating ripening and aging. Simultaneously, the surface of fruits and vegetables is susceptible to invasion by harmful microorganisms, making them highly prone to rotting and spoilage during storage and transportation, resulting in deterioration in quality. Statistics show that in my country, the annual loss rate due to improper storage and preservation of fruits and vegetables throughout the entire process from fresh harvesting, transportation, storage, to market sales reaches as high as 30%-50%.
[0003] Currently, the storage and preservation of fruits and vegetables mainly relies on physical (modified atmosphere, low temperature), chemical (chemical preservatives, such as sodium hypochlorite, stabilized chlorine dioxide, ozone, 1-MCP, etc.), or combined methods. These measures reduce fruit and vegetable losses to some extent and ensure nutritional quality. However, regardless of whether physical, chemical, or combined methods are used, the quality of the fruit cannot be guaranteed, and the loss rate remains above 10%. In particular, these physical and chemical preservation methods are mainly suitable for fruit and vegetable preservation in fixed locations (cold storage or supermarkets). With the rise of e-commerce platforms in recent years, fruit preservation in logistics relies on cold chain palletized small packaging boxes. The adverse factors such as transportation vibration and light exposure have increased significantly, making the environment of fruits and vegetables unstable and further increasing the difficulty of preservation. Current preservation methods cannot effectively solve the problem of moisture accumulation caused by the respiration of cold chain fruits and vegetables. High humidity exacerbates fruit mold growth, and commonly used modified atmosphere methods cannot be used in palletized small packaging, easily leading to fruit spoilage. Therefore, there is an urgent need to explore green preservation packaging technologies with high environmental adaptability.
[0004] Currently, most gaskets used in fruit and vegetable preservation are made of plastic foam and absorbent paper, whose functions are limited to cushioning, reducing mechanical damage to the fruit, and absorbing water. Multifunctional smart gasket technology has not yet been researched for fruit and vegetable packaging. Built-in preservation gasket technology can embed self-responsive modified atmosphere materials into the gasket, creating a gasket that releases CO2 within the packaging. This forms a novel modified atmosphere technology that reduces the respiration intensity of fruits and vegetables, inhibits nutrient loss, and reduces the occurrence of post-harvest diseases, thereby improving the preservation effect of fruits and vegetables. In view of this, this invention is proposed. Summary of the Invention
[0005] The purpose of this invention is to provide a preservative pad that achieves active modified atmosphere storage by releasing CO2, which is expected to provide consumers with a new green preservation method and reduce the spoilage loss of fruits and vegetables. A method for preserving fruits and vegetables using active modified atmosphere storage by releasing CO2 is characterized by the following steps:
[0006] (1) Heat the aqueous solution of the green polymer material in a water bath until it dissolves.
[0007] (2) Add citric acid microcapsule particles and sodium bicarbonate to the dissolved polymer material solution, disperse them evenly, and control the mass ratio of the added encapsulated citric acid to sodium bicarbonate to be 48-50:7.
[0008] (3) Pour the polymer material solution containing citric acid microcapsule particles onto a plate. After it solidifies, pour the polymer material solution containing sodium bicarbonate and antibacterial essential oil onto the upper layer. After solidification, vacuum freeze-dry the gasket.
[0009] The present invention has the following advantages and features:
[0010] This invention utilizes the principle that citric acid reacts with sodium bicarbonate to generate CO2, preparing a self-releasing CO2 preservation pad. Since the reaction between the two phases would rapidly release gas and cause CO2 loss, sodium alginate is used to encapsulate citric acid, controlling the reaction rate and achieving a slow-release effect. This allows more gas to be released gradually, improving preservation and inhibiting fruit and vegetable spoilage. This invention is the first to apply an automated modified atmosphere packaging pad to fruit and vegetable preservation. Its scientific and reasonable design combines a gel with CO2-releasing functional factors, antibacterial essential oils, and moisture-absorbing materials through a layer-by-layer preparation method. This synergistic effect makes it suitable for fruit and vegetable storage and cold chain pallet-style small packaging. It can inhibit respiration, improve antioxidant capacity, and reduce spoilage rate, solving the problems of traditional preservation sheets / pads / papers having limited functionality and poor long-term performance. It is green and safe, with good application prospects. Attached Figure Description
[0011] Figure 1 Visual effect and design principle diagram of the gasket
[0012] Figure 2 The image shows the antibacterial effect of food preservation pads against Escherichia coli, Staphylococcus aureus, and Aspergillus niger.
[0013] Figure 3 Before and after photos of the food storage mat absorbing water;
[0014] Figure 4 Images showing the effects of preserving strawberries under room temperature and refrigeration conditions.
[0015] Figure 5 Color changes of strawberries at room temperature and during cold storage;
[0016] Figure 6 The changes in weight loss and firmness of strawberries during room temperature and cold storage preservation;
[0017] Figure 7 Image showing the effect of grape preservation;
[0018] Figure 8 Image showing the effect of preserving goji berries. Detailed Implementation
[0019] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased on the market.
[0020] The present invention will be further described below with reference to the embodiments and accompanying drawings:
[0021] (1) Prepare citric acid microcapsule particles by mixing sodium alginate, citric acid and trehalose. The ratio of sodium alginate to trehalose to citric acid is 1:1:2 to 1:1:4. Add the mixture to water with a mass of 10 times that of sodium alginate, stir magnetically until uniform, and then inject it into a 1%-5% CaCl2 solution to form microcapsule particles. After washing with water three times, freeze dry for later use.
[0022] (2) Heat the aqueous solution of the green polymer material in a water bath until it dissolves.
[0023] (3) Add citric acid microcapsule particles and sodium bicarbonate to the dissolved polymer material solution, disperse them evenly, and control the mass ratio of the added encapsulated citric acid to sodium bicarbonate to be 48-50:7.
[0024] (4) Pour the polymer material solution containing citric acid microcapsule particles onto a plate. After it solidifies, pour the polymer material solution containing sodium bicarbonate and antibacterial essential oil onto the upper layer. After solidification, vacuum freeze-dry the gasket.
[0025] Example 1: (1) Sodium alginate 0.5g, trehalose 0.5g, and citric acid 1g were placed in 25ml of water, magnetically stirred until uniform, and then injected into 1% CaCl2 solution with a syringe to form microcapsule particles; after washing three times with water, they were freeze-dried for later use. (2) A 10% gelatin solution was heated in a 50℃ water bath until dissolved. (3) 4.8g of citric acid microcapsules were added to 10ml of gelatin solution and poured into a plate. After solidification, 0.7g of sodium bicarbonate and 0.5ml of cinnamon essential oil were added to 10ml of gelatin solution, dispersed evenly, poured into a plate, and then freeze-dried under vacuum after solidification.
[0026] Example 2: (1) Sodium alginate 1g, trehalose 1g, and citric acid 4g were placed in 50ml of water, magnetically stirred until uniform, and then injected into a 2% CaCl2 solution using a syringe to form microcapsule particles; after washing three times with water, they were freeze-dried for later use. (2) A 3% gellan gum solution was heated in a 65℃ water bath until dissolved. (3) 7.2g of citric acid microcapsules were added to 15ml of gellan gum solution and poured into a plate. After solidification, 1.05g of sodium bicarbonate and 1ml of thyme essential oil were added to 15ml of gellan gum solution, dispersed evenly, poured into a plate, and then freeze-dried under vacuum after solidification.
[0027] The preservation mat can be cut to specific sizes to meet preservation needs. Experiments show that one 9cm circular preservation mat, placed on top of the preservation box, is most effective for every 1 kg of fruit. This preservation mat is suitable for post-harvest cold storage and e-commerce cold chain distribution. It can inhibit respiration, improve antioxidant capacity, and reduce spoilage rate, solving the problems of traditional preservation sheets / mats / papers, such as limited functionality and poor durability, and has excellent application prospects. The preservation mat with self-releasing CO2 inside packaging, prepared by the method of this patent application, was applied to berry preservation experiments, and the results are as follows:
[0028] (1) As Figure 2 As shown, the food preservation mat has antibacterial effects against Escherichia coli, Staphylococcus aureus, and Aspergillus niger.
[0029] (2) Figure 3 As shown, this food storage mat has good water absorption, with a water absorption rate of up to 79%.
[0030] (3) Figure 4 As shown, this preservation mat can extend the shelf life of strawberries to three days at room temperature and to eight days under refrigeration; Figure 5-6 As shown, the preservation pad has a good inhibitory effect on the browning degree, weight loss rate and hardness reduction of strawberries.
[0031] (4) Figure 7 As shown, this preservation mat can extend the shelf life of grapes to 7-10 days.
[0032] (5) Figure 8 As shown, this preservation mat can extend the shelf life of goji berries to 7-8 days.
Claims
1. A food preservation pad that can self-release CO2 within packaging, characterized in that, Includes the following steps: (1) Heat the aqueous solution of the green polymer material in a water bath until it dissolves; (2) Add citric acid microcapsule particles and sodium bicarbonate to the dissolved polymer material solution, disperse them evenly, and control the mass ratio of the added encapsulated citric acid to sodium bicarbonate to be 48-50:
7. (3) Pour the polymer material solution containing citric acid microcapsule particles onto a plate. After it solidifies, pour the polymer material solution containing sodium bicarbonate and antibacterial essential oil onto the upper layer. After solidification, vacuum freeze-dry the gasket.
2. The food preservation pad that can self-release CO2 within the packaging according to claim 1, characterized in that, The polymer solution is selected and its concentration is 10%-15% gelatin solution, or 2%-5% guar gum solution, or 2%-5% chitosan solution.
3. The food preservation pad that can self-release CO2 within the packaging according to claim 1, characterized in that, The requirement for water bath heating is to heat in a water bath at 40-75℃ until dissolved.
4. The food preservation pad that can self-release CO2 within the packaging according to claim 1, characterized in that, The citric acid is formed by encapsulating sodium alginate into citric acid microcapsule particles.
5. The citric acid microcapsule particles formed by encapsulating sodium alginate according to claim 4, characterized in that, It is made by mixing sodium alginate, citric acid and trehalose, with the following ratios by mass fraction: sodium alginate: trehalose: citric acid 1:1:2 to 1:1:
4. The mixture is added to water at a mass of 10 times that of sodium alginate, magnetically stirred until homogeneous, and then injected into a 1%-5% CaCl2 solution using a syringe to form microcapsule particles. After washing three times with water, the particles are freeze-dried for later use.
6. The food preservation pad that can self-release CO2 within the packaging according to claim 1, characterized in that, The mass ratio of the added encapsulated citric acid to sodium bicarbonate is 48-50:
7.
7. The food preservation pad that can self-release CO2 within the packaging according to claim 1, characterized in that, The required volume of the added polymer solution is such that the thickness of the freeze-dried pad reaches 1-5 mm.
8. The food preservation pad that can self-release CO2 within the packaging according to claim 1, characterized in that, The antibacterial essential oil is cinnamon essential oil, or cinnamaldehyde, or thyme essential oil, or tea tree essential oil, or eucalyptus essential oil, and its volume is 0.5%-1% of the volume of the upper polymer material solution.