SO2 slow-release agent, preparation method thereof and application of SO2 slow-release agent in storage process of muscat grapes
By preparing and using a specific ratio of SO2 slow-release agent, the problem of unstable SO2 preservative release rate in existing technologies has been solved, achieving efficient preservation of Muscat grapes, maintaining the appearance and aroma quality of the fruit, and reducing the risk of fruit damage and residue.
Patent Information
- Application Number
- CN202511978885.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-02-10
AI Technical Summary
Existing SO2 preservatives have an unstable release rate during grape storage, leading to fruit damage or poor anti-corrosion effects. They also have bleaching and residue problems, making it difficult to effectively maintain the post-harvest aroma and appearance quality of Muscat grapes.
A slow-release SO2 agent composed of preservative A and preservative B in a mass ratio of 3:1, including sodium metabisulfite, silica gel, rosin, stearic acid, 2-aminobutane sulfate, and anhydrous sodium carbonate, was prepared by a specific mixing and packaging method and used in pre-storage treatment to control the SO2 release rate.
It significantly extended the shelf life of Muscat grapes, maintained the appearance and aroma of the fruit, reduced fruit damage and SO2 residue, and enhanced the application value of clean production.
Smart Images
Figure CN121489009A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fruit preservation technology, and more specifically, to an SO2 slow-release agent, its preparation method, and its application in the storage of Muscat grapes. Background Technology
[0002] Grapes are one of my country's four major fruits, rich in nutrients and highly favored by consumers. Reports indicate that my country's annual grape production has reached 6.8 billion tons, ranking first globally and making it one of the world's largest grape-consuming markets. Among them, Muscat grapes, also known as Muscat grapes, are a European-Asian grape variety with a unique rose aroma, whose taste and distinctive fragrance are beloved by consumers. However, Muscat grapes are non-climacteric fruits with thin skins and high sugar and water content, making them highly susceptible to post-harvest spoilage and aroma loss, severely impacting their economic value. Therefore, developing precise and efficient preservation methods is crucial for delaying post-harvest spoilage and aroma loss in Muscat grapes.
[0003] Currently, grape storage and preservation technologies are mainly divided into two categories: physical preservation and chemical preservation. Physical preservation technologies mainly include low-temperature preservation, ozone preservation, modified atmosphere storage, and irradiation preservation. These are characterized by being green and pollution-free, but their preservation effects are limited, especially in inhibiting the loss of aroma after harvest in Muscat grapes. Furthermore, some technologies suffer from high costs and complex operations. Chemical preservation technologies mainly include sulfur dioxide, chlorine dioxide, 1-MCP, ethanol, hydrogen sulfide, sec-butylamine, and calcium peroxide. These technologies are effective in maintaining the aroma and quality of grapes after harvest, especially sulfur dioxide and chlorine dioxide. However, the dosage and mechanism of action of chemical preservation technologies for grapes still require further research. Excessive dosage may lead to bleaching and excessive residues.
[0004] Among existing preservation technologies, SO2 treatment is widely recognized as the most effective fungicide for controlling grape gray mold and other fungal diseases. Studies have also shown that SO2 plays an important role in various biological processes, such as regulating grape sugar metabolism, activating phenylpropane metabolism, and accelerating aroma synthesis. Currently, SO2 applications mainly include fumigation or controlled-release preservative technology. Controlled-release preservative technology is further divided into tablets and powders based on dosage form. Tablets primarily employ slow-release technology, while powders utilize faster-release technology. However, both dosage forms have significant technical drawbacks in their application: tablet preparation is complex and costly; more importantly, the SO2 release rate is highly dependent on ambient humidity and temperature, making stable control difficult. Furthermore, excessively high storage temperatures can lead to excessive SO2 release in the early stages, potentially causing bleaching damage to the grapes; insufficient release later reduces the preservation effect. Conversely, excessively low temperatures result in insufficient SO2 release throughout the storage period, failing to effectively inhibit bacterial growth.
[0005] The problem with powdered preservatives is that their release rate is too fast, which can easily lead to excessively high local concentrations, causing serious bleaching and fruit drop, among other pesticide damage.
[0006] In conclusion, regardless of whether it is in tablet or powder form, the dosage of SO2 used needs to be strictly controlled. Insufficient concentration will not achieve the purpose of preservation, while excessive concentration will cause the fruit to fade and bleach, or even damage the fruit tissue structure.
[0007] Therefore, it is particularly important to find and develop efficient and precise preservation methods to maintain the aroma and quality of grapes after harvest. Summary of the Invention
[0008] To address the problems existing in the prior art, the first objective of this invention is to provide an SO2 slow-release agent and its preparation method. The slow-release agent obtained by this method can reduce SO2 residue during grape preservation, stabilize the SO2 release rate, reduce fruit damage, extend shelf life, and improve clean production, thus having broad application value. The second objective of this invention is to provide a method for storing and preserving Muscat grapes. This method, while extending the shelf life of Muscat grapes, can improve their aroma quality during storage, maintain their commercial value, and has good application prospects.
[0009] To solve the above problems, the present invention adopts the following technical solution.
[0010] An SO2 slow-release agent comprises preservative A and preservative B in a mass ratio of 3:1. Preservative A comprises the following raw materials, by weight percentage: 85-87% sodium metabisulfite, 8-9% silica gel, 3-4% rosin, and 1-2% stearic acid; preservative B comprises the following raw materials, by weight percentage: 85-87% 2-aminobutane sulfate and 13-15% anhydrous sodium carbonate.
[0011] Furthermore, the preservative A comprises the following raw materials, by weight percentage: 86.7% sodium metabisulfite, 8.7% silica gel, 3.3% rosin and 1.3% stearic acid; the preservative B comprises the following raw materials, by weight percentage: 86% 2-aminobutane sulfate and 14% anhydrous sodium carbonate.
[0012] The present invention also provides a method for preparing an SO2 slow-release agent, the method being as follows: P1: Preparation of preservative A: Sodium metabisulfite, 60-mesh silica powder, 60-mesh pulverized rosin and stearic acid are mixed evenly, added to a double cone, mixed at 85℃ for 5-7 minutes, then cooled naturally and pulverized and sieved to obtain preservative A; P2: Preparation of preservative B: After pulverizing 2-aminobutane sulfate, add anhydrous sodium carbonate together to a vertical mixer and mix evenly to obtain preservative B; P3: After packaging the preservative A prepared in step P1, package it together with the preservative B prepared in step P2.
[0013] This invention also provides a method for storing and preserving Muscat grapes, comprising the following steps: S1: Material Collection: Select Muscat grapes with uniform ripeness as materials; S2: Pre-storage treatment: After washing and drying, the Muscat grapes are placed in a cold storage for pre-cooling. After pre-cooling, they are packaged into microporous membranes and a certain amount of the SO2 slow-release agent packet mentioned above is added. S3: Storage of Muscat grapes: After pretreatment, Muscat grapes are stored in a cold storage.
[0014] Furthermore, in step S1, Muscat grapes that are uniform in size and color, free from pests and diseases, free from mechanical damage, and have fruit stems are selected.
[0015] Furthermore, in step S2, the pre-cooling temperature is 0±0.5℃ and the pre-cooling time is 26h.
[0016] Furthermore, the amount of the SO2 slow-release agent used is 9 g / kg.
[0017] Furthermore, in step S3, the temperature of the cold storage is 0±1 ℃ and the humidity is 75%. Compared with the prior art, the advantages of this invention are: I. The preservation method provided in this solution can effectively preserve the quality of Muscat grapes, with outstanding preservation effects on their appearance quality and storage resistance. It significantly delays the decay of Muscat grapes, slows down color changes, and significantly reduces weight loss and berry drop rates, while preserving aroma quality. There is no bleaching effect, which improves the storage quality of grapes, maintains their commercial value, and has good application prospects.
[0018] II. The slow-release agent prepared by this method can reduce SO2 residue in grape preservation, stabilize the SO2 release rate, reduce fruit damage, extend shelf life and improve clean production, and has a wide range of application value. Attached Figure Description
[0019] Figure 1 This is a schematic diagram showing the effect of different treatments on the weight loss rate of Muscat grapes in Test Example 2 of the present invention; Figure 2 This is a schematic diagram showing the effect of different treatments on the fruit drop rate of Muscat grapes in Test Example 2 of the present invention; Figure 3 This is a schematic diagram showing the effect of different treatments on the color difference of Muscat grapes in Test Example 2 of the present invention; Figure 4 This is a schematic diagram showing the effect of different treatments on the volatile compound content of Rosehip grapes in Test Example 2 of this invention; Figure 5 This is a schematic diagram of PCA analysis showing the effect of different treatments on the volatile compound content of Muscat grapes in Test Example 2 of this invention. Detailed Implementation
[0020] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Unless otherwise specified, the technical means used in this invention are methods well known to those skilled in the art. Furthermore, the embodiments should be understood as illustrative and not limiting of the scope of the invention; the essence and scope of the invention are defined only by the claims. For those skilled in the art, various changes or modifications to the SO2 slow-release agent formulation, dosage, and precise temperature control operation in these embodiments, without departing from the essence and scope of the invention, are also within the scope of protection of this invention. The microporous membrane, sulfite, silica gel, rosin, stearic acid, 2-aminobutane sulfate, and anhydrous sodium carbonate used in this invention are all commercially available.
[0021] Example 1:
[0022] An SO2 slow-release agent comprises 3 parts by weight of preservative A and 1 part by weight of preservative B, and is prepared as follows: (1) Preparation of preservative A: First, mix 26 kg sodium metabisulfite, 2.6 kg silica gel powder (60 mesh), 1 kg rosin powder (60 mesh) and 0.4 kg stearic acid evenly, heat in a double cone to 85 ℃ for about 6 min, after the above steps are completed, cool naturally to room temperature, pulverize the cooled mixture below 30 mesh and sieve, and package it in 3g packages; (2) Preparation of preservative B: After pulverizing 2-aminobutane sulfate to below 60 mesh, 25.8 kg of 2-aminobutane sulfate and 4.2 kg of anhydrous sodium carbonate were mixed evenly in a vertical mixer; (3) Pack the preservative A prepared in step (1) and the preservative B prepared in step (2) into bags at a ratio of 3g of preservative A and 1.5g of preservative B per bag, and seal them to obtain the final SO2 slow-release agent product.
[0023] Example 2:
[0024] The difference between this embodiment and Embodiment 1 is that: the preservative A includes the following raw materials, by weight percentage: 85% sodium metabisulfite, 9% silica gel, 4% rosin and 2% stearic acid; the preservative B includes the following raw materials, by weight percentage: 87% 2-aminobutane sulfate and 13% anhydrous sodium carbonate.
[0025] Example 3:
[0026] The difference between this embodiment and Embodiment 1 is that: the preservative A includes the following raw materials, by weight percentage: 87% sodium metabisulfite, 8% silica gel, 3% rosin and 1% stearic acid; the preservative B includes the following raw materials, by weight percentage: 87% 2-aminobutane sulfate and 13% anhydrous sodium carbonate.
[0027] Test Example 1: The SO2 slow-release agents involved in Examples 1-3 and the SO2 preservatives purchased from the market in Comparative Example 1 were placed in preservation bags containing Muscat grapes. The SO2 content in the preservation bags was measured at 0, 1, 3 and 7 days. On the 7th day, the SO2 residue in the Muscat grapes was measured according to GB5009.34-2022 National Food Safety Standard - Determination of Sulfur Dioxide in Food. The test results are shown in the table below.
[0028] .
[0029] .
[0030] According to the data in Tables 1 and 2, the SO2 slow-release agent used in Examples 1-3 released SO2 at a slower rate compared to Comparative Example 1. Even after several days of storage, the SO2 content maintained in the preservation bag remained high, significantly extending its effective duration. Simultaneously, this slow-release agent substantially reduced the SO2 residue in the grapes, better balancing the preservative effect with food safety. This effectively solves the common problem of traditional SO2 preservatives—excessively rapid initial release and insufficient later-stage efficacy—thus avoiding the phenomenon of high initial sulfur damage risk and weak later-stage preservative effect.
[0031] Example 4: Method for storing Muscat grapes The storage method includes the following steps: (1) Material harvesting: Select Muscat grapes that are uniform in size and color, free from pests and diseases, free from mechanical damage, and have fruit stalks as materials. (2) Pre-storage treatment: After washing and drying, the Muscat grapes were placed in a cold storage at 0±0.5 ℃ for 26 hours to pre-cool. After pre-cooling, they were packaged into microporous membranes and two packets of SO2 slow-release agent prepared in Example 1 were added at a dose of 9g / kg. (3) Storage of Muscat grapes: After processing, Muscat grapes are stored in a cold storage at a temperature of 0±1℃ and a relative humidity of 75%.
[0032] Comparative Example 2: With other conditions remaining unchanged, the difference between this comparative example and Example 2 is that in step (2), pre-cooling is not performed and SO2 slow-release agent packets are not added after dispensing.
[0033] Test Example 2: 1. The preservation effect of the storage methods involved in Example 4 and Comparative Example 2 were tested respectively. The specific test contents are as follows: (1) Weight loss rate determination: The determination was performed using a weighing method. Three bunches of grapes were fixed for each treatment, and their weight was measured at each sampling point. The measurements were repeated three times. Results were expressed as a percentage (%) and calculated using the following formula: ; In the formula: m1: Initial weight of Muscat grapes, in kg; m2: The weight of Muscat grapes taken each time is measured, in kg.
[0034] (2) Determination of particle loss rate: The determination was performed using a gravimetric method. Three bags of grapes, each weighing 1.6 kg, were fixed for each treatment. The weight was measured at each sampling point, and the measurements were repeated three times. The results were expressed as a percentage (%) and calculated using the following formula: ; In the formula: m1: Initial weight of Muscat grapes, in kg; m3: Weight of Muscat grapes dropped during each sampling, in kg.
[0035] (3) Determination of color difference in Muscat grapes: For each treatment, 10 grapes were taken, and the L*, a*, and b* values at the center of the grape skin were measured using a colorimeter. The measurements were repeated 10 times, and the ΔL*, Δa*, and Δb* values were recorded. The ΔE value was calculated using the following formula: ; In the formula: ΔL*: The difference between the L* value of Muscat grapes and the initial value; Δa*: The difference between the a* value of Muscat grapes and the initial value; Δb*: The difference between the b* value of Muscat grapes and the initial value; ΔE: Scalar value of color difference in Muscat grapes (4) Determination of volatile compound content in Muscat grapes: Cut the grapes into small pieces, accurately weigh 2 g, and place them in a 20 mL headspace vial for analysis. Analyze using a FlavorSpec® gas chromatograph-ion mobility spectrometer; GC-IMS conditions are shown in Table 3.
[0036] .
[0037] 2. Results and Analysis After preserving the Muscat grapes according to the methods of Example 4 and Comparative Example 2, the preservation results were measured at 0 days, 15 days, 45 days, and 75 days, respectively, according to the above-mentioned measurement indicators and methods. The preservation effect of the Muscat grapes was measured according to the above-mentioned measurement indicators and methods, and the specific results are shown below.
[0038] (1) Effects of different treatments on weight loss rate of Muscat grapes: Depend on Figure 1 It was found that, within the first 45 days of storage, Comparative Example 2 had the highest weight loss rate, reaching 12.8%, while the weight loss rate of Example 4 was significantly lower than that of Comparative Example 2 (p < 0.05). By 75 days, the weight loss rate of Comparative Example 2 had significantly increased to 52.5%, while the weight loss rate of Example 4 was 4.9%. This indicates that the treatment in Example 4 can effectively slow down moisture evaporation and help maintain fruit quality and freshness.
[0039] (2) Effects of different treatments on the berry drop rate of Muscat grapes: Depend on Figure 2It was found that the shattering rate of Comparative Example 2 was 0.4% at 15 days, which increased significantly to 21.6% at 45 days (p<0.05). At the same stage, the shattering rate of Example 4 was 2.5%, which was significantly lower than that of Comparative Example 2. At the end of storage, the shattering rate of the two groups was > that of Comparative Example 2 (p<0.05). This indicates that the treatment of Example 4 can effectively reduce the occurrence of shattering and maintain the good integrity and commercial value of the fruit.
[0040] (3) Effects of different treatments on color difference in Muscat grapes: The L* value represents the change in fruit brightness, reflecting the color change trend of grapes during storage. Table 4 shows that after 75 days of storage, the L* value of Comparative Example 2 decreased to -8.4, while the L* value of Example 4 was -2.0. This indicates that the treatment in Example 4 effectively slowed down the darkening of Muscat grapes and maintained fruit brightness.
[0041] The a* value is used to evaluate the red and green components of the fruit. As shown in Table 4, with the extension of storage time, the a* value of Comparative Example 2 gradually decreased to 1.7, while the a* value of Example 4 decreased to -0.1. This indicates that the treatment in Example 4 can slow down the reddening rate of Muscat grapes, thereby maintaining a better appearance quality.
[0042] The b* value represents the yellow and blue components in the fruit color. As shown in Table 4, the b* value of Example 4 is always higher than that of Comparative Example 2, indicating that the Muscat grapes in the Example 4 treatment group have a smaller degree of browning.
[0043] .
[0044] △E effectively reflects the degree of color change of Muscat grapes during storage, from Figure 3 It can be seen that △E increases throughout the storage period, with Comparative Example 2 showing the fastest growth. Compared with Example 4, Comparative Example 2 shows the most significant color difference. This result is consistent with the results observed in L*, a*, and b* values, further indicating that untreated grapes have greater color difference and poorer color stability during storage.
[0045] (4) Effects of different preservative treatments on the volatile compound content of Muscat grapes: Depend on Figure 4As can be seen, 47 compounds were detected in Example 4, and 43 compounds were identified in the spectral library, mainly aldehydes and esters. The substances in the orange region mostly showed a decreasing trend, with significant changes observed over 15 days, primarily aldehydes and esters. The substances in the purple region showed an increasing trend, but only 2-octanol, 2-n-butylfuran, and ethyl 3-hydroxybutyrate were present in higher amounts in Example 4 during the later stages of storage. All other substances were present in higher amounts in Comparative Example 2. It is speculated that in Comparative Example 2, which lacks SO2 inhibitors, the senescence process of grapes may have accelerated, promoting respiration and leading to increased VOC release or synthesis.
[0046] Figure 5 Data showed that PC1 and PC2 contributed a total of 95.36%, with more significant differences between groups at 15 and 75 days of storage. PCA results indicated that SO2 treatment in both the early and late stages of storage had a significant impact on the aroma quality of Muscat grapes (Note: CK is Comparative Example 2, and SO2 is Example 4).
[0047] The results above show that the treatment in Example 4 can better preserve the fruit of Muscat grapes, reduce weight loss and berry drop, stabilize their color, affect their aroma quality, significantly extend the storage time of Muscat grapes, and stabilize their commercial value.
[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A slow-release agent for SO2, characterized in that: The product comprises preservative A and preservative B in a mass ratio of 3:
1. Preservative A comprises the following raw materials, by weight percentage: 85-87% sodium metabisulfite, 8-9% silica gel, 3-4% rosin, and 1-2% stearic acid. Preservative B comprises the following raw materials, by weight percentage: 85-87% 2-aminobutane sulfate and 13-15% anhydrous sodium carbonate.
2. The method for preparing an SO2 slow-release agent according to claim 1, characterized in that: The preparation steps are as follows: P1: Preparation of preservative A: Sodium metabisulfite, 60-mesh silica powder, 60-mesh pulverized rosin and stearic acid are mixed evenly, added to a double cone, mixed at 85℃ for 5-7 minutes, then cooled naturally and pulverized and sieved to obtain preservative A; P2: Preparation of preservative B: After pulverizing 2-aminobutane sulfate, add anhydrous sodium carbonate together to a vertical mixer and mix evenly to obtain preservative B; P3: After packaging the preservative A prepared in step P1, package it together with the preservative B prepared in step P2.
3. A method for storing and preserving Muscat grapes, characterized in that: Includes the following steps: S1: Material Collection: Select Muscat grapes with uniform ripeness as materials; S2: Pre-storage treatment: After washing and drying, the Muscat grapes are placed in a cold storage for pre-cooling. After pre-cooling, they are packaged into microporous membranes and a certain amount of SO2 slow-release agent packet as described in claim 1 is added. S3: Storage of Muscat grapes: After pretreatment, Muscat grapes are stored in a cold storage.
4. The method for storing and preserving Muscat grapes according to claim 3, characterized in that: In step S1, select Muscat grapes that are uniform in size and color, free from pests and diseases, free from mechanical damage, and have fruit stems.
5. The method for storing and preserving Muscat grapes according to claim 3, characterized in that: In step S2, the pre-cooling temperature is 0±0.5℃ and the pre-cooling time is 26h.
6. The method for storing and preserving Muscat grapes according to claim 3, characterized in that: The dosage of the SO2 slow-release agent is 9 g / kg.
7. The method for storing and preserving Muscat grapes according to claim 3, characterized in that: In step S3, the temperature of the cold storage is 0±1 ℃ and the humidity is 75%.