A fruit and vegetable supply chain use burst bead fresh-keeping card and its preparation method and application

Abstract

The application discloses a fruit and vegetable supply chain burst bead fresh-keeping card and a preparation method and application thereof, and belongs to the technical field of fresh-keeping cards.The fruit and vegetable supply chain burst bead fresh-keeping card comprises the following steps: (1) preparing a carbon dot (CDs) / ZnO composite; (2) preparing a CDs / ZnO / CO2 burst bead; and (3) preparing a CDs / ZnO / CO2 burst bead intelligent fresh-keeping card: dissolving carboxymethyl cellulose sodium and the CDs / ZnO / CO2 burst bead in water, adding glycerol, uniformly mixing and stirring, and then placing in an oven for drying to obtain the intelligent fresh-keeping card with carboxymethyl cellulose sodium as a base. The fresh-keeping card prepared from the CDs / ZnO / CO2 burst bead can release ZnO and CO2 under the triggering of ultraviolet light and moisture generated by fruit respiration, inhibit respiration and ethylene production of respiration non-jump type perishable fruits in a fresh-keeping box, and release ZnO to inhibit growth and reproduction of spoilage microorganisms, so that the fruit supply chain is inhibited from rotting.

Description

Technical Field

[0001] This invention belongs to the field of food preservation technology, specifically relating to a popping bead preservation card for fruit and vegetable supply chain, its preparation method, and its application. Background Technology

[0002] In recent years, with the rapid development of the global economy and the improvement of people's living standards, the demand for fruit has gradually increased. However, due to factors such as poor logistics and storage conditions, perishable fruits are easily affected by various environmental factors in the supply chain, leading to quality deterioration and greatly reducing the competitiveness and profit margin of the fruit industry. Therefore, the quality control and management of perishable fruits has become an important research topic in the fruit industry. Among them, the research on the specific characterization and composite control methods of quality deterioration of non-climacteric perishable fruits such as strawberries, grapes, and cherries is of great significance. These fruits are easily affected by external conditions such as oxygen, carbon dioxide, and humidity, which can significantly affect the freshness, color, and taste of the fruit. Therefore, it is necessary to comprehensively consider multiple control methods, such as packaging materials and temperature and humidity control, to ensure the quality and safety of the fruit.

[0003] Nano-sized ZnO can generate strong oxidizing agents such as hydroxyl radicals (OH) and reactive oxygen species (ROS), which can damage bacterial cell structure and lead to bacterial death. It also possesses advantages such as chemical and thermal stability, non-toxicity, and low cost. However, its antibacterial efficacy is limited by a significant particle aggregation effect. In photocatalysis, ZnO acts as a photocatalyst, absorbing light and catalyzing water / oxygen to produce cytotoxic ROS. ROS are highly reactive oxidants capable of inactivating microorganisms, including viruses, bacteria, spores, and protozoa. The ROS generated by ZnO damages the cell wall and subsequently the cell membrane. Once the cell wall is damaged, the change in cell wall permeability allows active substances to easily reach the cell membrane. Finally, due to lipid peroxidation, the cell membrane is attacked by active substances, leading to bacterial inactivation. Furthermore, under light irradiation, ZnO generates electron-hole pairs after being excited by photon energy. These electron-hole pairs then react with adsorbed oxygen and water on the surface in a redox reaction, producing highly activated superhydroxyl radicals (·OH) and superoxide radicals (·O2). -Finally, the carbon-carbon double bonds (C=C) and carbon-hydrogen bonds (CH) of the ethylene molecule are broken, leading to the photocatalytic degradation of ethylene. However, ZnO has a wide photocatalytic bandgap (3.2 eV) and can only absorb and utilize 3%–5% of solar energy (wavelength less than 387 nm), limiting its light utilization. By modifying ZnO to broaden its photoresponse range and promote charge separation, the photocatalytic performance of ZnO can be improved. Carbon dots (CDs) have potential applications in many fields such as sensors, bioimaging, photoelectrocatalysis, solar cells, and fluorescence sensing due to their excellent optical properties, low toxicity, good biocompatibility, and photoinduced electron transfer ability. Under light excitation, the active hydroxyl groups generated from the holes in a photocatalyst possess a reaction energy of 1686.1 kJ / mol, higher than the chemical bond energies of various organic compounds, such as CC (347.4 kJ / mol), CH (414.4 kJ / mol), CN (305.6 kJ / mol), CO (351.6 kJ / mol), HO (464.6 kJ / mol), NH (389.3 kJ / mol), C=C (611.1 kJ / mol), and C=O (736.70 kJ / mol). The photocatalytic degradation of ethylene is related to its functional groups or chemical bonds. The light wavelengths required to break C=C and CH in C₂H₄ are 196.1 nm and 289.7 nm, respectively. Therefore, under the action of a 254 nm ultraviolet lamp, C=C breaks, and ethylene undergoes direct photodegradation.

[0004] However, since the main causes of decay in non-climacteric fruits are fungal decay and the fruit's respiration and metabolism, reducing the respiration rate of non-climacteric fruits is an effective way to extend their shelf life. Currently, the main method for reducing the respiration rate of non-climacteric fruits is modified atmosphere packaging (MAP), which is considered helpful in maintaining post-harvest quality and extending storage time. Currently, carbon dioxide gas is widely used in MAP. Appropriate carbon dioxide concentrations can reduce respiration, prevent discoloration, reduce the risk of infection and microbial growth, and prevent cell damage. However, traditional MAP implementation is cumbersome and expensive. Considering that non-climacteric fruits produce moisture during respiration, we decided to use CDs / ZnO / CO2 capsules as an alternative to MAP. The moisture produced by the respiration of non-climacteric fruits and ultraviolet light can act as external triggers to release ZnO and CO2 from the preservation card, thereby producing a positive gas preservation effect and inhibiting the respiration and ethylene release of perishable fruits. Strawberries are mainly sold in small plastic or wooden baskets and wrapped in plastic bags with large holes. This packaging does not meet the requirements for long-term cold storage. Furthermore, 50% of consumers open fruit packaging before refrigeration, thus damaging modified atmosphere packaging before consumption. Conversely, using our proposed method, if the fruit produces moisture during respiration, and UV light triggers the preservation card, it can continue to release CO2 and ZnO. When the packaging is opened, the carbon dioxide remains and inhibits the respiration of perishable fruit.

[0005] The aforementioned published literature differs from this invention in that it uses a CDs / ZnO / CO2 bursting bead preservation card. The release of CDs / ZnO from the preservation card is triggered by a UV lamp installed in the preservation box, generating O2- and ·OH under UV light irradiation, thereby significantly improving ethylene degradation efficiency. Using CDs to modify ZnO can effectively inhibit the recombination of photogenerated electrons and holes, and their recombination has a synergistic effect on enhancing photocatalytic efficiency. Water vapor produced by fruit respiration triggers CO2 release, thus inhibiting the respiration of perishable fruits and the release of ethylene, while also preventing fruit decay. Summary of the Invention

[0006] Technical Problem Solved: To address the aforementioned technical problems, this invention provides a fruit and vegetable supply chain popping bead preservation card, its preparation method, and its application. A CDs / ZnO composite is prepared using ultrasound combined with a high-voltage electrostatic field assisted technology. CDs / ZnO / CO2 popping beads are then prepared using this composite and fabricated into preservation cards. When triggered by ultraviolet light and moisture generated by fruit respiration, the CDs / ZnO / CO2 popping beads in the preservation card release ZnO and CO2, inhibiting the respiration of non-climacteric perishable fruits and the production of ethylene in the preservation box, thereby inhibiting their spoilage.

[0007] Technical solution: A method for preparing popping bead preservation cards for fruit and vegetable supply chain, the steps are as follows: (1) Preparation of carbon dots (CDs) / ZnO complex: carbon dots (CDs) and nano ZnO are dissolved in distilled water, and the two are fully mixed by shearing with a high-speed shearing machine; then they are placed in an ultrasonic-high voltage electrostatic field device for further dispersion, and placed in a high-pressure reactor for reaction at 300-500℃ for 3-6h; after cooling, the precipitate is collected by centrifugation, and then the CDs / ZnO complex is obtained by vacuum freeze drying; (2) Preparation of CDs / ZnO / CO2 popping beads: white sugar is dissolved in water, CDs / ZnO complex is added, the mass ratio of white sugar to CDs / ZnO complex is (30-60):1, the mixed solution is added to the popping bead preparation reactor, the mixture is stirred and dissolved at 70-100℃ until the moisture content is reduced to no more than 2%. Stop heating; then turn off the popping bead preparation and stir to inject CO2 at a flow rate of 20-40 mL / min for 5-10 min and then cool to solid within 1 min. Sugar-CDs / ZnO will decompose into small particles due to instantaneous decompression, and the result is CDs / ZnO / CO2 popping beads; (3) Preparation of CDs / ZnO / CO2 popping bead smart preservation card: Dissolve sodium carboxymethyl cellulose and CDs / ZnO / CO2 popping beads in water and add glycerol, wherein the concentration of sodium carboxymethyl cellulose is 2wt.%-5wt.%, the concentration of CDs / ZnO / CO2 popping beads is 10wt.%-20wt.%, and the glycerol content is 10wt.%-30wt.%. After mixing and stirring evenly, remove bubbles by ultrasound, and then place in an oven to dry until the moisture content does not exceed 4%, thus preparing a smart preservation card based on sodium carboxymethyl cellulose.

[0008] The parameters for the high-speed shearing machine are 4000-8000 r / min and shearing time is 5-10 min.

[0009] The above ultrasonic-high voltage electrostatic field parameters are: electric field strength of 10-40kV, ultrasonic frequency of 30-60Hz, ultrasonic power of 300-600W, and time of 20-50min.

[0010] The above-mentioned popping bead preparation pressure is 10-30 MPa, CO2 injection time is 5-10 min, and flow rate is 20-40 mL / min.

[0011] The mixing and dissolving temperature of the mixture in step (2) is 80°C.

[0012] The above-mentioned method is used to specifically characterize and comprehensively manage the deterioration of the quality of non-catastrophic perishable fruits in the supply chain.

[0013] The specific application method is to fix the popping bead preservation card to the top of the food storage container and place an ultraviolet light lamp inside the food storage container.

[0014] The wavelengths of the aforementioned ultraviolet lamps are UV-A: 315-400nm; UV-B: 280-315nm; UV-C: 180-280nm.

[0015] The above characterization was based on the measured values ​​of decay rate, total bacterial count, and mold and yeast count. The prepared fruit and vegetable supply chain popping bead preservation card was applied to the preservation of strawberries for 6 days, blueberries for 10 days, and cherries for 9 days. The inhibition ranges of decay rate, total bacterial count, and mold and yeast count for the three fruits were 33.90%-42.03%, 2.57log CFU / g-4.20log CFU / g, and 1.31log CFU / g-2.83log CFU / g, respectively.

[0016] Beneficial effects: The CDs / ZnO / CO2 burst beads used in this invention release ZnO and CO2 from the CDs / ZnO / CO2 burst beads when triggered by ultraviolet light and moisture produced by fruit respiration. This inhibits the respiration of non-climacteric perishable fruits and the production of ethylene in the preservation box. Furthermore, the released ZnO can inhibit the growth and reproduction of spoilage microorganisms, thereby preventing the spoilage of non-climacteric perishable fruits in the supply chain. Attached Figure Description

[0017] Figure 1 The changes in the decay rate of strawberries (a), blueberries (b), and cherries (c) during storage;

[0018] Figure 2 The changes in total bacterial count of strawberries (a), blueberries (b), and cherries (c) during storage;

[0019] Figure 3 The changes in mold and yeast counts in strawberries (a), blueberries (b), and cherries (c) during storage. Detailed Implementation

[0020] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of the present invention.

[0021] Example 1: A method for controlling strawberry spoilage and quality deterioration in the supply chain using a CDs / ZnO / CO2 bursting bead preservation card.

[0022] (1) Preparation of CDs / ZnO composite: 3g of carbon dots (CDs) and 3g of nano-ZnO were dissolved in 50mL of distilled water and sheared for 5min with a high-speed shear machine at a speed of 5000r / min to ensure thorough mixing. Then, the mixture was placed in an ultrasonic-high voltage electrostatic field (electric field strength of 20kV, ultrasonic frequency of 40Hz, ultrasonic power of 400W) device for further dispersion for 30min. The mixture was then placed in a high-pressure reactor and reacted at 400℃ for 3h. After cooling, the precipitate was collected by centrifugation and then freeze-dried under vacuum (cold trap temperature -60℃, absolute pressure: 10Pa) for 48h to obtain the CDs / ZnO composite.

[0023] (2) Preparation of CO2 popping beads: 500g of white sugar and 10g of CDs / ZnO complex were dissolved in 100mL of water. The mixed solution was added to the popping bead preparation reactor (QZCJ-50A fully automatic continuous vacuum sugar boiling and aeration stirring pot). The mixture was then stirred at 500rpm and dissolved at 80℃ until the moisture content dropped to below 2%, at which point heating was stopped. The reactor was then closed, and CO2 was injected at a flow rate of 30mL / min during stirring for 8min. The mixture was then rapidly cooled to a solid state within 1min. Due to the instantaneous decompression, it decomposed into small particles, which were the resulting CDs / ZnO / CO2 popping beads.

[0024] (3) Preparation of CDs / ZnO / CO2 popping bead preservation card: 2g sodium carboxymethyl cellulose and 2g CDs / ZnO / CO2 popping beads were dissolved in 100mL of water, and 10wt.% of glycerol was added to the system. After mixing and stirring evenly, the mixture was sonicated at 300W and 30KHz for 30min to remove bubbles, and then placed in an oven at 40℃ to dry until the moisture content was below 4wt.%.

[0025] (4) Composite control treatment: Place strawberries in a preservation box, fix the CDs / ZnO / CO2 popping bead preservation card prepared in step (3) to the top of the preservation box with tape, and place an ultraviolet lamp (254nm) in the preservation box.

[0026] (5) Cold storage: Store the product from step (4) at 4°C.

[0027] (6) Characterization of quality deterioration: The rot rate, total number of colonies and number of molds and yeasts of strawberries during the storage process in step (5) were measured.

[0028] from Figure 1As can be seen, the total bacterial count, mold and yeast count, and rot rate of the strawberries in Example 1 after 14 days of storage were 7.07 log CFU / g, 4.21 log CFU / g, and 65.41%, respectively. According to the International Committee on Microbiology of Foods (ICMES), when the microbial content in food reaches 7.00 log CFU / g, the food becomes sensorily unacceptable and loses its edible value. Therefore, the shelf life of the strawberries is 12 days.

[0029] Example 2: A CDs / ZnO / CO2 bursting bead preservation card for controlling blueberry spoilage and quality deterioration in the supply chain.

[0030] (1) 3g of carbon dots (CDs) and 3g of nano-ZnO were dissolved in 50mL of distilled water and sheared for 5min with a high-speed shear machine at a speed of 5000r / min to ensure thorough mixing. Then, the mixture was placed in an ultrasonic-high voltage electrostatic field (electric field strength of 20kV, ultrasonic frequency of 40Hz, ultrasonic power of 400W) device for further dispersion for 30min. The mixture was then placed in a high-pressure reactor and reacted at 400℃ for 3h. After cooling, the precipitate was collected by centrifugation and then freeze-dried under vacuum (cold trap temperature -60℃, absolute pressure: 10Pa) for 48h to obtain the CDs / ZnO composite.

[0031] (2) Preparation of CO2 popping beads: 500g of white sugar and 10g of CDs / ZnO complex were dissolved in 100mL of water. The mixed solution was added to the popping bead preparation reactor (QZCJ-50A fully automatic continuous vacuum sugar boiling and aeration stirring pot). The mixture was then stirred at 500rpm and dissolved at 80℃ until the moisture content dropped to below 2%, at which point heating was stopped. The reactor was then closed, and CO2 was injected at a flow rate of 30mL / min during stirring for 8min. The mixture was then rapidly cooled to a solid state within 1min. Due to the instantaneous decompression, it decomposed into small particles, which were the resulting CDs / ZnO / CO2 popping beads.

[0032] (3) Preparation of CDs / ZnO / CO2 bursting beads preservation card: 2g sodium carboxymethyl cellulose and 2g CDs / ZnO / CO2 bursting beads were dissolved in 100mL water and 10% glycerol was added. After mixing and stirring evenly, the mixture was sonicated at 300W and 30KHz for 30min to remove bubbles, and then placed in an oven at 40℃ to dry until the moisture content was below 4%.

[0033] (4) Composite control treatment: Place blueberries in a food storage box, fix the CDs / ZnO / CO2 popping bead food storage card prepared in step (3) to the top of the food storage box with tape, and place an ultraviolet lamp (254nm) in the food storage box.

[0034] (5) Cold storage: Store the product from step (4) at 4°C.

[0035] (6) Characterization of quality deterioration: The rot rate, total number of colonies and number of molds and yeasts of blueberries during the storage process in step (5) were measured.

[0036] from Figure 2 As can be seen, the total bacterial count, mold and yeast count, and rot rate of the blueberries in Example 2 after 25 days of storage were 7.36 log CFU / g, 4.50 log CFU / g, and 63.88%, respectively. According to the International Committee on Microbiology of Foods (ICMES), when the microbial content in food reaches 7.00 log CFU / g, the food becomes sensorily unacceptable and loses its edible value. Therefore, the shelf life of strawberries is 20 days.

[0037] Example 3: A CDs / ZnO / CO2 bursting bead preservation card for controlling cherry spoilage and quality deterioration in the supply chain.

[0038] (1) 3g of carbon dots (CDs) and 3g of nano-ZnO were dissolved in 50mL of distilled water and sheared for 5min with a high-speed shear machine at a speed of 5000r / min to ensure thorough mixing. Then, the mixture was placed in an ultrasonic-high voltage electrostatic field (electric field strength of 20kV, ultrasonic frequency of 40Hz, ultrasonic power of 400W) device for further dispersion for 30min. The mixture was then placed in a high-pressure reactor and reacted at 400℃ for 3h. After cooling, the precipitate was collected by centrifugation and then freeze-dried under vacuum (cold trap temperature -60℃, absolute pressure: 10Pa) for 48h to obtain the CDs / ZnO composite.

[0039] (2) Preparation of CO2 popping beads: 500g of white sugar and 10g of CDs / ZnO complex were dissolved in 100mL of water. The mixed solution was added to the popping bead preparation reactor (QZCJ-50A fully automatic continuous vacuum sugar boiling and aeration stirring pot). The mixture was then stirred at 500rpm and dissolved at 80℃ until the moisture content dropped to below 2%, at which point heating was stopped. The reactor was then closed, and CO2 was injected at a flow rate of 30mL / min during stirring for 8min. The mixture was then rapidly cooled to a solid state within 1min. Due to the instantaneous decompression, it decomposed into small particles, which were the resulting CDs / ZnO / CO2 popping beads.

[0040] (3) Preparation of CDs / ZnO / CO2 bursting beads preservation card: 2g sodium carboxymethyl cellulose and 2g CDs / ZnO / CO2 bursting beads were dissolved in 100mL water and 10% glycerol was added. After mixing and stirring evenly, the mixture was sonicated at 300W and 30KHz for 30min to remove bubbles, and then placed in an oven at 40℃ to dry until the moisture content was below 4%.

[0041] (4) Composite control treatment: Place the cherries in a food storage box, fix the CDs / ZnO / CO2 popping bead food storage card prepared in step (3) to the top of the food storage box with tape, and place an ultraviolet lamp (254nm) in the food storage box.

[0042] (5) Cold storage: Store the product from step (4) at 4°C.

[0043] (6) Characterization of quality deterioration: The rot rate, total number of colonies and number of molds and yeasts of cherries were measured during the storage process in step (5).

[0044] from Figure 3 As can be seen, the total bacterial count, mold and yeast count, and spoilage rate of the cherries in Example 3 after 18 days of storage were 7.47 log CFU / g, 4.62 log CFU / g, and 64.88%, respectively. According to the International Committee on Microbiology of Foods (ICMES), when the microbial content in food reaches 7.00 log CFU / g, the food becomes sensorily unacceptable and loses its edible value. Therefore, the shelf life of the cherries is 15 days.

[0045] Comparative Example 1: Quality Deterioration of Non-Closing Respiratory Perishable Fruits in the Supply Chain

[0046] (1) Packaging: Place non-climacteric perishable fruits in a food storage container;

[0047] (2) Refrigerated storage: Store the product from step (1) at 4°C.

[0048] (3) Characterization of quality deterioration: The decay rate, total number of colonies and number of molds and yeasts of non-climacteric perishable fruits during the storage process in step (2) were determined.

[0049] from Figure 1 , Figure 2 and Figure 3 As can be seen, in Comparative Example 1, the total bacterial counts of strawberries, blueberries, and cherries stored for 6, 14, and 9 days were 7.54 log CFU / g, 7.73 log CFU / g, and 7.29 log CFU / g, respectively. At this point, the mold and yeast counts in strawberries, blueberries, and cherries were 4.63 log CFU / g, 5.36 log CFU / g, and 4.37 log CFU / g, respectively. The spoilage rates of strawberries, blueberries, and cherries were 64.42%, 61.03%, and 66.32%, respectively, exceeding 60%. According to the International Committee on Microbiology of Foods (ICMES), when the microbial concentration in food reaches 7.00 log CFU / g, the food becomes sensorily unacceptable and loses its edible value. Therefore, the shelf lives of strawberries, blueberries, and cherries are 4 days, 5 days, and 6 days, respectively.

[0050] Comparative Example 2: A CDs / ZnO complex for controlling spoilage and quality deterioration of non-climacteric perishable fruits in the supply chain.

[0051] (1) Preparation of CDs / ZnO composite: 3g of carbon dots (CDs) and 3g of nano-ZnO were dissolved in 50mL of distilled water and sheared for 5min with a high-speed shear machine at a speed of 5000r / min to ensure thorough mixing. Then, the mixture was placed in an ultrasonic-high voltage electrostatic field (electric field strength of 20kV, ultrasonic frequency of 40Hz, ultrasonic power of 400W) device for further dispersion for 30min. The mixture was then placed in a high-pressure reactor and reacted at 400℃ for 3h. After cooling, the precipitate was collected by centrifugation and then freeze-dried under vacuum to obtain the CDs / ZnO composite.

[0052] (2) Control and treatment: Place non-climacteric perishable fruits in a food storage box. The CDs / ZnO complex prepared in step (1) is evenly distributed on the tape and fixed to the top of the food storage box. Place an ultraviolet lamp (254nm) in the food storage box.

[0053] (3) Refrigerated storage: Store the product from step (2) at 4°C.

[0054] (4) Characterization of quality deterioration: The decay rate, total number of colonies and number of molds and yeasts of non-climacteric perishable fruits during the storage process in step (3) were measured.

[0055] from Figure 1 , Figure 2 and Figure 3 As can be seen, in Comparative Example 2, the total bacterial counts of strawberries, blueberries, and cherries stored for 8, 20, and 12 days were 7.29 log CFU / g, 7.47 log CFU / g, and 7.08 log CFU / g, respectively. At this point, the mold and yeast counts in strawberries, blueberries, and cherries were 4.03 log CFU / g, 4.52 log CFU / g, and 4.15 log CFU / g, respectively. The spoilage rates of strawberries, blueberries, and cherries were 66.32%, 66.32%, and 62.44%, respectively, exceeding 60%. According to the International Committee on Microbiology of Foods (ICMES), when the microbial concentration in food reaches 7.00 log CFU / g, the food becomes sensorily unacceptable and loses its edible value. Therefore, the shelf lives of strawberries, blueberries, and cherries are 6 days, 10 days, and 9 days, respectively.

[0056] Comparative Example 3: A method for controlling spoilage and quality deterioration of non-catastrophic perishable fruits in the supply chain using CO2 burst beads.

[0057] (1) Preparation of CO2 popping beads: 500g of white sugar was dissolved in 100mL of water, and the mixture was added to the popping bead preparation reactor (QZCJ-50A fully automatic continuous vacuum sugar boiling and aeration stirring pot). The mixture was then stirred at 500rpm and dissolved at 80℃ until the moisture content decreased to below 2%, at which point heating was stopped. The reactor was then closed, and CO2 was injected at a flow rate of 30mL / min during stirring for 8 minutes at a pressure of 20MPa. The mixture was then rapidly cooled to a solid state within 1 minute. Due to the instantaneous decompression, it decomposed into small particles, which were then obtained as CO2 popping beads.

[0058] (2) Control and treatment: Place non-rapidly flammable fruits in a food storage box. The CO2 burst beads prepared in step (1) are evenly distributed on the tape and fixed to the top of the food storage box. Place an ultraviolet lamp (254nm) in the food storage box.

[0059] (3) Refrigerated storage: Store the product from step (2) at 4°C.

[0060] (4) Characterization of quality deterioration: The decay rate, total number of colonies and number of molds and yeasts of non-climacteric perishable fruits during the storage process in step (3) were measured.

[0061] from Figure 1 , Figure 2 and Figure 3 As can be seen, in Comparative Example 3, the total bacterial counts of strawberries, blueberries, and cherries after 8, 18, and 12 days of storage were 7.50 log CFU / g, 7.36 log CFU / g, and 7.46 log CFU / g, respectively. At this point, the mold and yeast counts in strawberries, blueberries, and cherries were 4.16 log CFU / g, 4.39 log CFU / g, and 4.48 log CFU / g, respectively. The spoilage rates of strawberries, blueberries, and cherries were 62.53%, 62.32%, and 60.32%, respectively, exceeding 60%. According to the International Committee on Microbiology of Foods (ICMES), when the microbial concentration in food reaches 7.00 log CFU / g, the food becomes sensorily unacceptable and loses its edible value. Therefore, the shelf lives of strawberries, blueberries, and cherries are 8 days, 10 days, and 9 days, respectively.

[0062] Comparative Example 4: A sodium carboxymethyl cellulose preservation card for controlling spoilage and quality deterioration of non-climacteric perishable fruits in the supply chain.

[0063] (1) Preparation of sodium carboxymethyl cellulose preservation card: 2g sodium carboxymethyl cellulose was dissolved in 100mL of water and 10% glycerol was added. After mixing and stirring evenly, the mixture was sonicated at 300W and 30KHz for 30min to remove air bubbles, and then placed in an oven at 40℃ to dry until the moisture content was below 4%.

[0064] (2) Control and treatment: Place non-climacteric perishable fruits in a preservation box, fix the sodium carboxymethyl cellulose preservation card prepared in step (1) to the top of the preservation box with tape, and place an ultraviolet lamp (254nm) in the preservation box.

[0065] (3) Refrigerated storage: Store the product from step (2) at 4°C.

[0066] (4) Characterization of quality deterioration: The decay rate, total number of colonies and number of molds and yeasts of non-climacteric perishable fruits during the storage process in step (3) were measured.

[0067] from Figure 1 , Figure 2 and Figure 3 As can be seen, in Comparative Example 4, the total bacterial counts of strawberries, blueberries, and cherries after 8, 16, and 12 days of storage were 7.35 log CFU / g, 7.56 log CFU / g, and 7.60 log CFU / g, respectively. At this point, the mold and yeast counts in strawberries, blueberries, and cherries were 4.36 log CFU / g, 4.54 log CFU / g, and 4.73 log CFU / g, respectively. The spoilage rates of strawberries, blueberries, and cherries were 63.74%, 67.42%, and 68.54%, respectively, exceeding 60%. According to the International Committee on Microbiology of Foods (ICMES), when the microbial concentration in food reaches 7.00 log CFU / g, the food becomes sensorily unacceptable and loses its edible value. Therefore, the shelf lives of strawberries, blueberries, and cherries are 8 days, 10 days, and 12 days, respectively.

[0068] The foregoing illustrative description of the invention and its embodiments is not restrictive. Therefore, if those skilled in the art are inspired by it and design similar structural methods and embodiments without departing from the spirit of the invention, they should all fall within the protection scope of the invention.

Claims

1. A method for preparing a fruit and vegetable supply chain popping bead preservation card, characterized in that, The steps are as follows: (1) Preparation of carbon dots (CDs) / ZnO complex: Carbon dots (CDs) and nano ZnO are dissolved in distilled water and sheared with a high-speed shear machine to mix them thoroughly; then they are placed in an ultrasonic-high voltage electrostatic field device for further dispersion, and placed in a high-pressure reactor for reaction at 300-500℃ for 3-6h; after cooling, the precipitate is collected by centrifugation and then the CDs / ZnO complex is obtained by vacuum freeze drying; (2) Preparation of CDs / ZnO / CO2 popping beads: White sugar is dissolved in water, and CDs / ZnO complex is added. The mass ratio of white sugar to CDs / ZnO complex is (30-60):

1. The mixed solution is added to the popping bead preparation reactor, the mixture is stirred and dissolved at 70-100℃ until the water content is reduced to no more than 2%, and heating is stopped; then the popping bead preparation is turned off, and CO2 is injected at a flow rate of 20-40 mL / min for 5-10 min and then 1 Within min, it is cooled into a solid. Sugar-CDs / ZnO will decompose into small particles due to instantaneous decompression, and the resulting product is CDs / ZnO / CO2 popping beads; (3) Preparation of CDs / ZnO / CO2 popping bead smart preservation card: Sodium carboxymethyl cellulose and CDs / ZnO / CO2 popping beads are dissolved in water and glycerol is added. The concentration of sodium carboxymethyl cellulose is 2 wt.%-5 wt.%, the concentration of CDs / ZnO / CO2 popping beads is 10 wt.%-20 wt.%, and the glycerol content is 10 wt.%-30 wt.%. After mixing and stirring evenly, the bubbles are removed by ultrasound, and then the product is placed in an oven to dry until the moisture content does not exceed 4%, thus producing a smart preservation card based on sodium carboxymethyl cellulose.

2. The method for preparing the fruit and vegetable supply chain popping bead preservation card according to claim 1, characterized in that, The parameters of the high-speed shearing machine are 4000-8000 r / min, and the shearing time is 5-10 min.

3. The method for preparing the fruit and vegetable supply chain popping bead preservation card according to claim 1, characterized in that, The pressure for preparing the bursting beads is 10-30 MPa, the CO2 injection time is 5-10 min, and the flow rate is 20-40 mL / min.

4. The method for preparing the fruit and vegetable supply chain popping bead preservation card according to claim 1, characterized in that, The mixing and dissolving temperature of the mixture in step (2) is 80 °C.

5. The application of the fruit and vegetable supply chain popping bead preservation card prepared by any of the preparation methods described in claims 1-4 in the specific characterization and composite control of the deterioration of the quality of non-catastrophic perishable fruits in the supply chain.

6. The application according to claim 5, characterized in that, Secure the popping bead preservation card to the top of the food storage container and place a UV lamp inside the container.

7. The application according to claim 6, characterized in that, The wavelength of the ultraviolet lamp is 254nm.

8. The application according to claim 7, characterized in that, The characterization was based on the measured values ​​of decay rate, total bacterial count, and mold and yeast count. The prepared fruit and vegetable supply chain popping bead preservation card was applied to the preservation of strawberries for 6 days, blueberries for 10 days, and cherries for 9 days. The inhibition ranges of decay rate, total bacterial count, and mold and yeast count for the three fruits were 33.90% - 42.03%, 2.57 log CFU / g - 4.20 log CFU / g, and 1.31 log CFU / g - 2.83 log CFU / g, respectively.

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