Preparation method and application of strawberry preservative

Abstract

The application discloses a preparation method and application of a strawberry antiseptic preservative, and comprises the following steps: adding allitridin sulfoxide into glycerol, mixing uniformly through high-speed shearing to form a stable mixed emulsion; adding clove essential oil into the stable mixed emulsion, mixing uniformly through high-speed shearing to form a compound antiseptic preservative based on allitridin sulfoxide; slowly adding hydroxyethyl cellulose into water, stirring until the hydroxyethyl cellulose is dissolved completely to form a hydroxyethyl cellulose emulsion; adding the antiseptic preservative based on allitridin sulfoxide into the hydroxyethyl cellulose emulsion, mixing uniformly through high-speed shearing to form a slow-release antiseptic preservative based on allitridin sulfoxide. The strawberry antiseptic preservative can effectively inhibit the germination and propagation infection of Botrytis cinerea, the main pathogenic bacterium of strawberry gray mold. In combination with the application of the slow-release antiseptic preservative pad and the slow-release antiseptic preservative box, the rot rate of the strawberry during a postharvest shelf life can be effectively reduced, the antioxidant capacity of the strawberry is improved, the preservation period is prolonged, and the good aroma flavor quality during storage can be maintained.

Description

Technical Field

[0001] This invention relates to the field of food preservation technology, and in particular to a method for preparing and applying a strawberry preservative. Background Technology

[0002] Strawberries have tender flesh and high water content. During the high temperatures of the harvest season, post-harvest respiration and metabolism are vigorous, resulting in strong transpiration. The harvesting and transportation processes are highly susceptible to mechanical damage and microbial invasion, leading to high rates of mold and rot, quality deterioration, and post-harvest losses as high as 30%. Currently, strawberry storage and transportation mainly rely on simple low-temperature preservation. However, low temperatures cannot completely inhibit the reproduction of pathogenic microorganisms and can also reduce the plant's own immunity and the flavor and quality of the fruit, affecting consumer choices. Furthermore, low-temperature storage technology is energy-intensive and costly, and currently, a complete cold chain cannot be achieved, which can actually exacerbate shelf-life spoilage losses. Current strawberry storage and transportation packaging primarily serves to reduce compression and mechanical damage and does not provide slow-release antibacterial, preservative, or freshness-preserving functions.

[0003] Currently, food preservatives are mainly divided into chemically synthesized and naturally derived types based on their source. The former is the most widely used, but chemically synthesized preservatives pose certain risks to human health and can easily lead to antibiotic resistance in pathogens. Natural extracts suffer from drawbacks such as unclear composition, unstable efficacy, and high cost. Therefore, biomimetic organic synthetic components based on key antibacterial components such as allicin from natural plants possess characteristics of high stability, good water solubility, improved compatibility, and high volatility. Compound preservatives formed from composite antibacterial and flavoring natural plant essential oils can effectively inhibit the reproduction of pathogenic microorganisms, have multiple antibacterial targets, are less prone to antibiotic resistance, and enhance plant cell immunity, maintaining good food quality while exhibiting high safety for human health and being environmentally friendly.

[0004] With the development of logistics and storage technologies, the development of green preservatives with high efficiency in antibacterial and anti-corrosion properties, as well as preservation equipment, is particularly urgent. However, there are no reports on the use of strawberry preservatives based on allicin, a key effective antibacterial component of garlic, combined with natural clove essential oil, or on the development of slow-release preservative mats and boxes based on this technology for strawberry preservation. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a method for preparing and applying a strawberry preservative, which aims to inhibit the germination, reproduction and infection of Botrytis cinerea, the main pathogen of gray mold in strawberries, reduce the rot rate of strawberries during the post-harvest shelf life, improve the antioxidant capacity of strawberries and extend the shelf life of strawberries.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for preparing a strawberry preservative, comprising the following steps:

[0007] S1: Add ethoxylate sulfoxide to glycerol and mix at high speed to form a stable emulsion;

[0008] S2: Add clove oil to the above stable mixed emulsion and mix at high speed to form a compound preservative based on allicin sulfoxide.

[0009] As a further improvement to the present invention, the following steps are also included:

[0010] S3: Slowly add hydroxyethyl cellulose to water and stir until fully dissolved to form a hydroxyethyl cellulose emulsion;

[0011] S4: Add the allicin sulfoxide-based preservative to the hydroxyethyl cellulose emulsion and mix it at high speed to form a slow-release allicin sulfoxide-based preservative.

[0012] As a further improvement of the present invention: the concentration of ethoxysulfoxide in the slow-release preservative based on ethoxysulfoxide is 80-300 ppm.

[0013] As a further improvement of the present invention: the ratio of the amount of allicin sulfoxide, glycerin, clove oil, hydroxyethyl cellulose and water is 1ml:(1~3)ml:(0.3~1)g:(10-20)g:10000ml.

[0014] As a further improvement of the present invention: the ratio of the amounts of allicin sulfoxide, glycerin, clove oil, hydroxyethyl cellulose and water is 1ml:3ml:0.5g:10g:10000ml.

[0015] This invention also provides a method for preparing a strawberry preservative, comprising the following steps:

[0016] S1: Take 1 ml of allicin sulfoxide, add 3 ml of glycerol, and use a high-speed shearing machine at 10000 r / min to shear and mix for 2 min to form a stable mixed emulsion;

[0017] S2: Add 0.5 ml of plant clove essential oil to the above stable mixed emulsion, sonicate for 5 min (ultrasound frequency 200-300W), and shear and mix for 2 min to form a compound preservative based on ethoxylate sulfoxide.

[0018] S3: Weigh 10.0g of hydroxyethyl cellulose and slowly add it to 10000ml of 80℃ hot water while stirring. Stir and mix for 1 hour to fully dissolve the hydroxyethyl cellulose and form an emulsion. After cooling and stabilizing, it becomes the hydroxyethyl cellulose emulsion.

[0019] S4: Add the compound preservative based on ethoxysulfoxide to 10000ml of hydroxyethyl cellulose emulsion, and shear and mix it for 5min at 10000r / min using a high-speed shearing machine to form a stable mixed emulsion, which is the slow-release preservative based on ethoxysulfoxide.

[0020] This invention also provides the use of strawberry preservatives in the preparation of fungal inhibitors, which can be used to inhibit the germination and reproduction of Botrytis cinerea, the pathogen of strawberry gray mold.

[0021] This invention also provides the use of strawberry preservatives in the preservation of strawberries.

[0022] The present invention also provides the use of strawberry preservatives in slow-release preservative pads.

[0023] This invention also provides the use of strawberry preservative in a slow-release preservative pad, comprising the following steps: selecting a three-layer non-woven fabric pad with a mesh on both sides and a fiber layer in the middle, one side of which is a dense, airtight film and the other side is a film containing small air pores; peeling off the film containing air pores, then evenly applying the prepared strawberry preservative to the fiber layer, then reapplying the peeled-off film containing air pores, and pressing it with a pressure of 2.0 kg / cm2 for 2 minutes to form a slow-release preservative pad containing strawberry preservative, with a thickness of approximately 5 mm.

[0024] The present invention also provides the use of strawberry preservatives in slow-release preservative containers.

[0025] This invention also provides the use of a strawberry preservative in a slow-release preservative storage box, comprising the following steps: placing a slow-release preservative pad under a slightly stiff plastic inner tray, punching three holes in each inner tray, and spacing the plastic inner tray 20mm from the bottom of the plastic packaging box. A 15mm gap is left between the slow-release preservative pad and the inner tray.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. This invention provides a method for preparing a strawberry preservative and its application in slow-release preservative pads and boxes. The strawberry preservative effectively inhibits the germination, reproduction, and infection of *Botrytis cinerea*, the main pathogen causing gray mold in strawberries. Combined with the application of slow-release preservative pads and boxes, it effectively reduces the spoilage rate of strawberries during the post-harvest shelf life, improves their antioxidant capacity, extends their shelf life, and maintains their good aroma and flavor quality during storage. Furthermore, this invention is simple to operate, low in cost, safe, and efficient, and has significant application value when combined with logistics packaging. Attached Figure Description

[0028] Figure 1The graph shows the inhibitory effect of different concentrations of strawberry preservatives on Botrytis cinerea in Example 1.

[0029] Figure 2 This is a diagram showing the in vivo reverse inhibition effect of the strawberry preservative in Example 2 on strawberry gray mold.

[0030] Figure 3 The image shows the effect of the strawberry preservative in Example 3 on reducing the rot rate of strawberries during low-temperature storage.

[0031] Figure 4 This is a diagram showing the effect of the slow-release preservative pad in Example 4 on controlling the rot rate of strawberries during low-temperature storage.

[0032] Figure 5 The graph shows the effect of the slow-release preservative pad treatment in Example 4 on the H2O2 content of strawberries.

[0033] Figure 6 The slow-release preservative pad treatment in Example 4 was applied to strawberry O 2- The effect of generation rate.

[0034] Figure 7 This is a graph showing the effect of the slow-release preservative pad treatment in Example 4 on the MDA content of strawberries.

[0035] Figure 8 This is a graph showing the effect of the slow-release preservative pad treatment in Example 4 on the SOD activity of strawberries.

[0036] Figure 9 This is a graph showing the effect of the slow-release preservative pad treatment in Example 4 on the CAT activity of strawberries. Detailed Implementation

[0037] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. The invention is now further described in conjunction with the accompanying drawings and embodiments:

[0038] This invention aims to overcome the drawbacks of existing chemical preservatives, such as drug resistance and safety hazards, the impurities and instability of natural extracts, and the lack of advanced logistics, storage, and transportation technologies and equipment. The primary objective is to develop a green, highly effective antibacterial and preservative agent based on an organic biomimetic synthesis of the active ingredient in natural allicin, combined with natural antibacterial and flavoring plant essential oils. This agent will be used to develop slow-release preservation mats and containers for strawberries, achieving the goals of inhibiting post-harvest rot, extending shelf life, improving post-harvest logistics and transportation efficiency, and reducing post-harvest losses. The compounded preservative can also function as an antibacterial agent, effectively inhibiting the spore germination and reproduction of *Botrytis cinerea*, the pathogen causing gray mold in strawberries.

[0039] An embodiment of the present invention provides a method for preparing a strawberry preservative, comprising the following steps:

[0040] S1: Add ethoxylate sulfoxide to glycerol and mix at high speed to form a stable emulsion;

[0041] S2: Add clove oil to the above stable mixed emulsion and mix at high speed to form a compound preservative based on allicin sulfoxide.

[0042] The ethoxylated sulfoxide mentioned in step S1 is an organically synthesized allicin derivative, which is different from plant-extracted allicin. The allicin derivative is an organically synthesized by the Institute of Chemistry, Chinese Academy of Sciences (patent number CN2011103241129), which retains the active sulfonic acid group of allicin and is a stable derivative without double bonds.

[0043] Another embodiment of the present invention provides a method for preparing a strawberry preservative, comprising the following steps:

[0044] S1: Add ethoxylate sulfoxide to glycerol and mix at high speed to form a stable emulsion;

[0045] S2: Add clove oil to the above stable mixed emulsion and mix at high speed to form a compound preservative based on ethoxylate sulfoxide;

[0046] S3: Slowly add hydroxyethyl cellulose to water and stir until fully dissolved to form a hydroxyethyl cellulose emulsion;

[0047] S4: Add the allicin sulfoxide-based preservative to the hydroxyethyl cellulose emulsion and mix it at high speed to form a slow-release allicin sulfoxide-based preservative.

[0048] In another example, the concentration of allicin sulfoxide in the sustained-release preservative based on allicin sulfoxide is 80-300 ppm.

[0049] In another example, the ratio of allicin sulfoxide, glycerol, clove oil, hydroxyethyl cellulose, and water is 1 ml:(1-3) ml:(0.3-1) g:(10-20) g:10000 ml.

[0050] In a specific application example, the ratio of allicin sulfoxide, glycerin, clove oil, hydroxyethyl cellulose, and water is 1ml:3ml:0.5g:10g:10000ml.

[0051] Another embodiment of the present invention provides a method for preparing a strawberry preservative, characterized by comprising the following steps:

[0052] S1: Take 1 ml of allicin sulfoxide, add 3 ml of glycerol, and use a high-speed shearing machine at 10000 r / min to shear and mix for 2 min to form a stable mixed emulsion;

[0053] S2: Add 0.5 ml of plant clove essential oil to the above stable mixed emulsion, sonicate for 5 min (ultrasound frequency 200-300W), and shear and mix for 2 min to form a compound preservative based on ethoxylate sulfoxide.

[0054] S3: Weigh 10.0g of hydroxyethyl cellulose and slowly add it to 10000ml of 80℃ hot water while stirring. Stir and mix for 1 hour to fully dissolve the hydroxyethyl cellulose and form an emulsion. After cooling and stabilizing, it becomes the hydroxyethyl cellulose emulsion.

[0055] S4: Add the compound preservative based on ethoxysulfoxide to 10000ml of hydroxyethyl cellulose emulsion, and shear and mix it for 5min at 10000r / min using a high-speed shearing machine to form a stable mixed emulsion, which is the slow-release preservative based on ethoxysulfoxide.

[0056] In the above example, the allicin derivative ethoxylate was synthesized by the Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, according to patent (CN 103058903B), and the clove essential oil was a clove extract purchased from Yuanye Biotechnology.

[0057] In another example, a method for preparing a strawberry preservative includes the following steps:

[0058] Weigh 10.0g of hydroxyethyl cellulose and slowly add it to 10000mL of distilled water at 80℃ while stirring. Then, heat and stir in a magnetic stirrer at 80℃±2℃ for 1 hour. After that, remove the beaker and let it cool to room temperature. Once cooled to room temperature, add 3.0g of glycerol to the beaker and mix well. Then, add 1mL of allicin sulfoxide to the beaker and mix. Use a high-speed shear mixer at 10000r / min to shear and mix for 2 minutes to form a stable emulsion, which is the strawberry preservative.

[0059] In a specific application example, the strawberry preservative is used in the preparation of a fungicide. It can be used to inhibit the germination and reproduction of *Botrytis cinerea*, the pathogen causing gray mold in strawberries.

[0060] In another specific application example, the use of strawberry preservatives in the preservation of strawberries.

[0061] In another specific application example, the strawberry preservative is used in a slow-release preservative pad.

[0062] In a specific application example, the use of strawberry preservative in a slow-release preservative pad includes the following steps: A three-layer non-woven fabric pad with a mesh structure on both sides and a fiber layer in the middle is selected. One side of the mesh is a dense, airtight film, and the other side is a film containing small air pores. The film with air pores is peeled off, and then the prepared strawberry preservative is evenly applied to the fiber layer. The peeled-off film with air pores is then reapplied, and the application is controlled at 2.0 kg / cm². 2 Press the pressure for 2 minutes to form a slow-release preservative pad containing strawberry preservatives, with a thickness of approximately 5 mm.

[0063] In the above example, a slow-release preservative and freshness-preserving pad is formed by combining a strawberry preservative with a three-layer non-woven fabric core. The outer two layers of non-woven fabric are selected, with one side having breathable pores. After peeling it off, the prepared strawberry preservative and freshness-preserving agent is evenly applied to the middle fiber layer. Then, the breathable pore-filled non-woven fabric layer is repositioned to create the slow-release preservative and freshness-preserving pad.

[0064] In another example, the use of strawberry preservatives in slow-release preservative containers.

[0065] In a specific application example, the use of strawberry preservatives in a slow-release preservative-containing container includes the following steps: A slow-release preservative pad is placed under a slightly stiff plastic inner tray, with three holes punched in each tray. The plastic inner tray is spaced 20mm from the bottom of the plastic packaging box. By leaving a 15mm gap between the slow-release preservative pad and the inner tray, the pad can slowly release the compound preservative while also providing some cushioning for the packaging.

[0066] In the above example, a slow-release preservative-preserving container is manufactured by combining a slow-release preservative-preserving pad with a perforated plastic container. The strawberry slow-release preservative-preserving container device consists of an independent inner groove with a shock-absorbing pad inside a PET strawberry packaging box. Each groove of the pad has three ventilation holes. The strawberries are placed precisely in the grooves, and the slow-release preservative-preserving pad is placed underneath. This increases shock resistance, and the volatile preservatives in the slow-release pad can evaporate, fumigating the strawberries through the ventilation holes in the grooves and the gaps between the pad and the packaging box, thus achieving a preservative-preserving effect.

[0067] In the example above, the strawberry packaging box has four ventilation holes on its four sides. These ventilation holes ensure that the fumigation concentration remains relatively stable, preventing it from accumulating too high and damaging the strawberries.

[0068] In another example, the slow-release preservative food storage box measures 170*135*55mm (length*width*height), with a height of 170*135*80mm (length*width*height) including the lid. It can be set to different packaging sizes of 9, 12, and 15 pieces.

[0069] When the above-mentioned strawberry preservative is used in slow-release preservative pads or slow-release preservative containers for the preservation of strawberries at room temperature, it can extend the shelf life by 2 days.

[0070] When the above-mentioned strawberry preservative is used in slow-release preservative pads or slow-release preservative boxes for the preservation of strawberries at low temperatures (0-2℃), it can extend the shelf life by 7 days and keep the rot rate below 5%.

[0071] This invention discloses a slow-release preservative based on hydroxyethyl cellulose, compounded with an organically synthesized allicin derivative, thionyl allicin, and clove essential oil emulsified together, and used to manufacture a strawberry preservation box. This product enhances the antioxidant capacity of strawberries and extends their high-quality shelf life, belonging to the field of fruit and vegetable storage and preservation technology. Firstly, the allicin derivative is an organically synthesized, stable derivative that retains sulfonic acid groups and does not contain double bonds. Secondly, the allicin derivative and clove essential oil are emulsified and subjected to high-speed shearing technology to form a stable compound preservative in a ratio of 1:(0.5-1). Finally, the preservative is combined with a non-woven fabric pad and an inner groove soft pad to manufacture the strawberry preservation box. The compound strawberry preservative and preservation box of this invention are low-cost, non-toxic, and harmless. Without affecting the normal quality of the harvested fruit, it significantly improves the antioxidant capacity of strawberries during storage, reducing the strawberry rot rate by more than 60%. This formula also has significant antibacterial ability, exhibiting a clear concentration dependence, and can be used to prepare green antibacterial agents, showing broad application prospects.

[0072] The strawberry preservative of this invention and its application in slow-release preservative mats and slow-release preservative boxes can inhibit post-harvest rot of strawberries, extend shelf life, improve the efficiency of post-harvest logistics and transportation, and reduce post-harvest losses. The strawberry preservative can also be used as an antibacterial agent, effectively inhibiting the spore germination and reproduction of *Botrytis cinerea*, the pathogen causing strawberry gray mold.

[0073] Example 1: In vitro inhibitory effect of strawberry preservative on gray mold

[0074] (1) Measure 1 ml of allicin sulfoxide with a pipette, add 3 ml of glycerol and 5.5 ml of sterile water, and use a high-speed shearing machine at 10000 r / min to shear and mix for 2 min to form a stable mixed emulsion.

[0075] (2) Add 0.5 ml of plant clove essential oil to the stable mixed emulsion, sonicate for 5 min (ultrasound frequency 200-300W), and shear and mix for 2 min to form a strawberry preservative.

[0076] (3) In a sterile environment, strawberry preservatives of different concentrations were added to the unconsolidated PDA medium, shaken well, and poured into glass dishes to cool. After the medium in the petri dishes had completely solidified, an activated Staphylococcus aureus mycelium with a diameter of 0.45 cm was inoculated into the center of a new petri dish, and the petri dishes were placed in a constant temperature incubator at 28℃. The diameter of the colonies was measured and recorded every 24 hours using the cross-sectional method.

[0077] according to Figure 1 It can be seen that different concentrations of strawberry preservatives showed significant inhibitory effects on Botrytis cinerea, with the 200 ppm concentration achieving a 100% inhibition rate.

[0078] Example 2: Experiment on the in vivo reverse-inhibition effect of strawberry preservative on strawberry gray mold

[0079] (1) Reverse spore culture: Botrytis cinerea cultured at 28℃ for 5 days was washed with sterile water and the spore suspension of Staphylococcus aureus was collected. Sterile water was used as the control.

[0080] (2) In vivo reverse inoculation: Select strawberries that are similar in size, color, and shape and have no mechanical damage. Before testing, disinfect the fruit with sodium hypochlorite (2% (v / v), 2 min), wash with distilled water, and air dry at room temperature. Puncture a 4 mm deep sterile needle around the equator of the strawberry fruit, and inoculate each fruit with 2 μL of spore solution or sterile water. Set up three replicates (10 fruits per replicate) for the treatment group and the control group.

[0081] (3) After inoculation, all fruit samples were stored at 25℃ and 90% RH; the experimental group was sprayed with strawberry preservative, in which the concentration of ethoxysulfate was 100ppm and the concentration of clove oil was 50ppm; the control fruit was sprayed with a liquid made by mixing 7ml of sterile water with 3ml of glycerol.

[0082] (4) Observe, take photos and samples daily.

[0083] Please see Figure 2 The first row represents the control group, and the second row represents the treatment group; Figure 2 It can be seen that the treatment group in the second row, after being treated with strawberry preservatives, can effectively inhibit the infection and amplification of gray mold on strawberries.

[0084] Example 3: Experiment on the effect of strawberry preservatives in reducing the rate of strawberry spoilage during low-temperature storage

[0085] (1) The treatment group was sprayed with strawberry preservative evenly on the surface of strawberries, with the concentration of ethoxysulfate 100ppm and the concentration of clove oil 50ppm; the control fruit was sprayed with a liquid made by mixing 7ml of sterile water and 3ml of glycerin.

[0086] (2) Each 1 kg of strawberry fruit was sprayed with about 1.6 to 3 ml of water, and a total of 300 strawberries were treated; 150 strawberries were in the treatment group and 150 strawberries were in the control group.

[0087] (3) Dry the strawberry surface with the strawberry preservative solution and store it at 0-2℃ with 80%-90% humidity.

[0088] (4) The storage time under low temperature was 25 days. Every 5 days, 30 strawberries from the treatment group and 30 strawberries from the control group were selected, for a total of 60 strawberries. The rot rate was counted, samples were frozen, and relevant physicochemical indicators were measured.

[0089] (5) Determination of strawberry rot rate:

[0090] The formula for determining the rot rate is: Rot rate = ∑(Rotten grade × Number of fruits at that grade) / (Highest rotten grade × Total number of fruits) × 100%.

[0091] The levels of decay are as follows: Level 0 is no decay; Level 1 is decay of 0 to 1 / 4 of the area; Level 2 is decay of 1 / 4 to 1 / 2 of the area; Level 3 is decay of 1 / 2 to 3 / 4 of the area; and Level 4 is decay of 3 / 4 to 4 / 4 of the area.

[0092] (6) Data processing and analysis:

[0093] Data were statistically processed using Origin 8.0 software and expressed as mean ± standard deviation (x±s). The t-test was used to compare the two groups, and P < 0.05 was considered statistically significant.

[0094] (7) Experimental results: Figure 3 It is evident that the rotting rate of the control group fruit began to be significantly higher than that of the treated group fruit treated with strawberry preservatives on day 15. By day 20, the rotting rate of the control group fruit reached 40%, while by day 25, the rotting rate reached nearly 100%. In contrast, the rotting rate of the treated group fruit treated with strawberry preservatives was only around 20% by day 25. Therefore, strawberry preservatives can effectively reduce the rotting rate of strawberries during low-temperature storage.

[0095] Example 4: Preparation of Slow-Release Preservative Pad and its Effect on Preserving Strawberries 1. Preparation of Slow-Release Preservative Pad

[0096] Select a three-layer non-woven fabric pad with a mesh structure on both sides and a fiber layer in the middle. One side of the mesh is a dense, airtight film, and the other side is a film with small air pores. Peel off the film with air pores, then evenly apply the prepared strawberry preservative to the fiber layer. Then, replace the peeled-off film with the film with air pores and apply a 2.0 kg / cm² pressure. 2 Press for 2 minutes to form a preservation pad containing strawberry preservatives, with a thickness of about 5 mm. The concentration of strawberry preservatives in the slow-release preservation pad coating is about 100 ppm, of which 70 ppm is allicin sulfoxide and 30 ppm is clove essential oil.

[0097] 2. Experiment on the effect of slow-release preservation box on the preservation and anti-corrosion of strawberries during low-temperature storage

[0098] Treatment Group: Select a shock-absorbing soft pad with a slot and make 3 ventilation holes in the slot. Place strawberries in the slot, leaving a 20mm gap between the slot and the bottom of the PET packaging box. Place the prepared slow-release preservative pad on the bottom of the plastic food storage box, and then place a double layer of non-woven slow-release preservative pad on the bottom. This effectively increases shock resistance, and the volatile strawberry preservative in the slow-release preservative pad can evaporate and fumigate the strawberries through the ventilation holes in the soft pad slot and the gap between the soft pad and the packaging box, achieving the effect of preservation. Four ventilation holes are set on the four sides of the strawberry packaging box to ensure that the fumigation concentration remains relatively stable and does not accumulate too high, thus preventing damage to the strawberry fruit. Select 200 strawberries with uniform ripeness, no mechanical damage, and no pests or diseases, and place them at a low temperature of 0-2℃ and a humidity of 80%-90%. Of the 100 samples, the rot rate was calculated every 5 days during storage. For the remaining 100 samples, 20 fruits were collected every 5 days, frozen in liquid nitrogen, and stored at -80°C for subsequent indicator determination. The control group fruits did not have allicin sulfoxide and clove oil added to their preservation pads; the rest of the preparation process was the same.

[0099] Depend on Figure 4It was observed that on day 15, the rot rate in the treatment group treated with the slow-release preservative pads was approximately 1%, while the rot rate in the control group reached 40%. On day 20, the rot rate in the control group reached 68.5%, while the rot rate in the treatment group treated with the slow-release preservative pads was only 4%. This demonstrates that the application of slow-release preservative pads with strawberry preservatives can effectively reduce rot during low-temperature storage of strawberries, extend shelf life, and maintain high marketability. This is related to the fact that the strawberry preservatives inhibit pathogenic microorganisms that cause strawberry rot, reduce rot, and enhance the antioxidant capacity of strawberries, thereby extending their shelf life.

[0100] 3. Determination of MDA, total ROS, H2O2 and antioxidant enzyme activity in strawberry fruit samples; Method for determination of malondialdehyde:

[0101] Measurement of malondialdehyde (MDA) content: 5g of strawberries were added to 10mL of 10% trichloroacetic acid solution, homogenized, and centrifuged at 4000r / min for 10min. 2.1mL of the supernatant was added to 2.1mL of 0.68% thiobarbituric acid solution, mixed, boiled in a water bath for 15min, cooled, and centrifuged again. The absorbance of the supernatant was measured at 450nm, 532nm, and 600nm. The control group was prepared using 2mL of 10% trichloroacetic acid solution instead of the extraction solution. Total ROS, H2O2, and antioxidant enzymes were measured according to the kit instructions.

[0102] Depend on Figure 5 and Figure 6 It can be seen that applying slow-release preservative pads inhibits the production of O2 in strawberry fruits. 2- Generation and accumulation of H2O2. 2- H₂O₂ is an important reactive oxygen species (ROS). ROS play a crucial role in the bioregulation of many plants throughout storage; they are considered cellularly toxic byproducts. ROS are highly reactive and attack a wide range of biomolecules, including proteins, DNA, and lipids such as polyunsaturated fatty acids. Throughout storage, the O₂ content of strawberry fruit treated with slow-release preservative pads... 2- Both H2O2 and H2O2 were lower than those in the control group.

[0103] Depend on Figure 7 It was found that applying slow-release preservative pads reduced cell membrane damage in strawberry fruits. MDA content is a key indicator of membrane damage and can reflect the integrity of the cell membrane. Throughout the storage period, the MDA level of strawberry fruits treated with slow-release preservative pads remained at a low level, consistently lower than that of the control group, indicating that applying slow-release preservative pads can reduce MDA accumulation and alleviate the degree of cell membrane damage.

[0104] Depend on Figure 8 and Figure 9The results showed that strawberry fruits treated with slow-release preservative pads had higher levels of SOD and CAT than the control group. SOD can scavenge superoxide free radicals and resist damage to the cell membrane system from reactive oxygen species or other peroxide free radicals. CAT, as a key enzyme in the strawberry antioxidant system, can decompose H2O2 generated by the SOD reaction, thereby inhibiting the accumulation of reactive oxygen species. This indicates that applying slow-release preservative pads can maintain the integrity of strawberry cell membranes.

[0105] The main functions of this invention are:

[0106] This invention provides a strawberry preservative and its application in slow-release preservative pads and boxes. The strawberry preservative effectively inhibits the germination, reproduction, and infection of *Botrytis cinerea*, the main pathogen causing gray mold in strawberries. Combined with the application of slow-release preservative pads and boxes, it effectively reduces the spoilage rate of strawberries during the post-harvest shelf life, improves their antioxidant capacity, extends shelf life, and maintains good aroma and flavor quality during storage. Furthermore, this invention is simple to operate, low in cost, safe, and efficient, and has significant application value when combined with logistics packaging.

[0107] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for preparing a strawberry preservative, characterized in that: Includes the following steps: S1: Add ethoxylate sulfoxide to glycerol and mix at high speed to form a stable emulsion; S2: Add clove oil to the above stable mixed emulsion and mix at high speed to form a compound preservative based on ethoxylate sulfoxide; S3: Slowly add hydroxyethyl cellulose to water and stir until fully dissolved to form a hydroxyethyl cellulose emulsion; S4: Add the allicin sulfoxide-based preservative to the hydroxyethyl cellulose emulsion and mix it at high speed to form a slow-release allicin sulfoxide-based preservative. The concentration of ethoxysulfoxide in the sustained-release preservative based on ethoxysulfoxide is 80-300 ppm. The ratio of the amounts of allicin sulfoxide, glycerin, clove oil, hydroxyethyl cellulose, and water is 1ml:(1-3)ml:(0.3-1)g:(10-20)g:10000ml.

2. The method for preparing a strawberry preservative according to claim 1, characterized in that: The ratio of allicin sulfoxide, glycerin, clove oil, hydroxyethyl cellulose, and water is 1ml:3ml:0.5g:10g:10000ml.

3. A method for preparing a strawberry preservative, characterized in that: Includes the following steps: S1: Take 1 ml of allicin sulfoxide, add 3 ml of glycerol, and use a high-speed shearing machine at 10000 r / min to shear and mix for 2 min to form a stable mixed emulsion; S2: Add 0.5 ml of plant clove essential oil to the above stable mixed emulsion, sonicate for 5 min at an ultrasonic frequency of 200-300 W, and shear and mix for 2 min to form a compound preservative based on ethoxylate sulfoxide. S3: Weigh 10.0 g of hydroxyethyl cellulose and slowly add it to 10000 ml of 80℃ hot water while stirring. Stir and mix for 1 hour to fully dissolve the hydroxyethyl cellulose and form an emulsion. After cooling and stabilizing, it is the hydroxyethyl cellulose emulsion. S4: Add the compound preservative based on ethoxysulfoxide to 10000 ml of hydroxyethyl cellulose emulsion, and shear and mix it for 5 min at 10000 r / min using a high-speed shearing machine to form a stable mixed emulsion, which is the slow-release preservative based on ethoxysulfoxide.

4. The use of the strawberry preservative according to any one of claims 1-3 in the preparation of a fungicide.

5. The use of the strawberry preservative according to any one of claims 1-3 in the preservation of strawberries.

6. The use of the strawberry preservative according to any one of claims 1-3 in a slow-release preservative pad.

7. The use of the strawberry preservative according to any one of claims 1-3 in a slow-release preservative container.

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