A composite gas low-pressure fumigation method for prolonging the shelf life of almonds and application thereof

Abstract

This application discloses a compound gas low-pressure fumigation method and its application for extending the shelf life of almonds, relating to the field of agricultural product storage technology. The method includes: drying harvested almonds to obtain dried almonds; packaging the dried almonds into bags according to a preset loading weight; placing the bagged dried almonds in a low-pressure fumigation chamber and adjusting the pressure of the chamber to a preset target pressure range; injecting compound gas into the chamber to perform short-term low-pressure fumigation on the dried almonds, obtaining short-term low-pressure fumigated dried almonds, and sealing and storing them at a temperature of 0 ℃~10 ℃. This method can effectively inhibit mold growth and lipid oxidation in almonds during storage, is environmentally friendly, has low cost, and stable effects, filling a gap in the commercial storage and preservation of almonds.

Description

Technical Field

[0001] This application relates to the field of agricultural product storage technology, and in particular to a compound gas low-pressure fumigation method and its application for extending the shelf life of almonds. Background Technology

[0002] Almonds, a specialty nut rich in unsaturated fatty acids, have seen continuous market demand growth in recent years due to their unique nutritional value and flavor, occupying an important position in the food processing and consumer markets. However, because almond kernels have a high oil content, they are highly susceptible to lipid oxidation during post-harvest storage, transportation, and sales. This manifests as a rancid taste in the kernels, severely impacting their sensory quality and nutritional value, shortening their shelf life and storage period, and causing significant economic losses. This has become one of the core bottlenecks restricting the high-quality development of the almond industry. Currently, various preservation methods for almonds exist (such as roasting, heat treatment, and oxygen-free packaging). Although these methods are diverse and constantly being improved, they have not been able to effectively solve this problem, leading to the development of gas fumigation methods.

[0003] Low-pressure fumigation has shown good preservation and loss reduction effects on agricultural products such as Xinjiang white apricots and chili peppers. It can not only delay the ripening and aging of the products, but also help maintain their appearance and nutritional quality. Current gas fumigation methods mostly use atmospheric pressure environments, resulting in uneven gas penetration, low utilization rates, unstable lipid oxidation inhibition effects, and the potential for gas residue or excessive dosage, which can affect consumer safety and hinder the achievement of green preservation.

[0004] Furthermore, existing technologies, such as single low-pressure treatment or single gas fumigation, have not been fully explored, resulting in low technological integration. They cannot fundamentally block the chain reaction of lipid oxidation in almonds, and the preservation costs are high, making them difficult to adapt to modern industrialized large-scale high-speed production. The preservation period still cannot meet the market's demand for long-term storage and long-distance transportation of almonds. Summary of the Invention

[0005] This application provides a composite gas low-pressure fumigation method and application for extending the shelf life of almonds. It solves the problems of unstable lipid oxidation effects, high costs, and inability to preserve almonds for long periods in existing gas fumigation methods. By controlling the initial moisture content of the almonds through sun-drying, a composite gas consisting of at least one inert gas and one non-inert gas is introduced to reduce the risk of hydrogen combustion and improve operational safety. This allows for short-term low-pressure fumigation of the almonds. This improves fumigation efficiency, inhibits mold growth and lipid oxidation during storage, and significantly enhances the commercial quality and storage stability of almonds while reducing gas consumption and processing time. It provides an efficient, safe, and environmentally friendly technical solution for the commercial preservation of almonds.

[0006] In a first aspect, a low-pressure fumigation method using a compound gas to extend the shelf life of almonds includes: drying harvested almonds to obtain dried almonds; packaging the dried almonds into bags according to a preset loading weight; placing the bagged dried almonds in a low-pressure fumigation chamber and adjusting the pressure of the low-pressure fumigation chamber to a preset target pressure range; wherein the preset target pressure range is lower than atmospheric pressure; injecting a compound gas into the low-pressure fumigation chamber adjusted to the preset target pressure range to perform a short-term low-pressure fumigation treatment on the dried almonds, obtaining the short-term low-pressure fumigated dried almonds, and sealing and storing them at a storage temperature of 0 ℃ to 10 ℃; wherein the compound gas contains at least one inert gas and one non-inert gas.

[0007] In conjunction with the first aspect, in one possible implementation, the drying process of the harvested almonds to obtain dried almonds includes: drying the harvested almonds using hot air drying to obtain the dried almonds with a moisture content between 4% and 6%.

[0008] In conjunction with the first aspect, in one possible implementation, the step of loading the dried almonds into bags according to a preset loading weight includes: placing the dried almonds in a mesh bag; the preset loading weight is 5.00 kg ± 0.10 kg per bag.

[0009] In conjunction with the first aspect, in one possible implementation, before injecting the composite gas into the low-pressure fumigation chamber adjusted to the preset target pressure range, the method further includes: mixing the composite gas using a gas mixer; wherein the composite gas consists of hydrogen and helium.

[0010] In conjunction with the first aspect, in one possible implementation, the concentration of the composite gas includes: a hydrogen concentration of 25 μL / L to 40 μL / L and a helium concentration of 15 μL / L to 100 μL / L.

[0011] In conjunction with the first aspect, in one possible implementation, adjusting the pressure value of the low-pressure fumigation chamber to a preset target pressure range includes: reducing the pressure inside the low-pressure fumigation chamber to the preset target pressure range of 0.5 kPa to 5 kPa using a vacuum system.

[0012] In conjunction with the first aspect, in one possible implementation, the short-time low-pressure fumigation treatment of the dried almonds includes: the short-time low-pressure fumigation treatment time is 0.5 h to 8 h, and the temperature is 15 ℃ to 25 ℃.

[0013] In conjunction with the first aspect, in one possible implementation, obtaining the dried almonds after short-term low-pressure fumigation treatment and sealing them for preservation includes: placing the dried almonds after short-term low-pressure fumigation treatment into a PET bag and sealing them for preservation in a light-proof and oxygen-proof manner.

[0014] Furthermore, this application also provides the application of a low-pressure fumigation method using composite gases in extending the shelf life of almonds.

[0015] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: This application describes a low-pressure fumigation method and application for extending the shelf life of almonds using a composite gas. The method utilizes a low-pressure fumigation chamber to mix a composite gas consisting of inert and non-inert gases, and employs short-duration low-pressure fumigation to inhibit lipid oxidation and extend the shelf life of almonds. The low-pressure environment not only helps reduce the amount of hydrogen and helium used but also significantly shortens the processing time. During the low-pressure fumigation process, helium is introduced as an inert gas, ensuring both the fumigation effect and improving the safety of hydrogen use. This effectively inhibits mold growth and lipid oxidation in almonds during storage. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The almond morphology image on day 0 of the blank control group provided in this application embodiment; Figure 2 Morphological image of almonds on day 14 of the blank control group provided in this application embodiment; Figure 3 Morphological diagram of almonds on day 14 of the low-pressure treatment group provided in this application embodiment; Figure 4 Morphological image of almonds on day 14 of the hydrogen short-time low-pressure fumigation treatment group provided in the embodiments of this application; Figure 5 Morphological image of almonds on day 14 of the helium short-time low-pressure fumigation treatment group provided in this application embodiment; Figure 6 Comparative morphological images of shell-less and shelled almonds in the composite gas short-time low-pressure fumigation treatment group provided in the embodiments of this application on the 14th day; Figure 7A comparative graph showing the change in moisture content of almond kernels over time in a blank control group provided in this application embodiment; Figure 8 A comparison chart showing the change in moisture content of almond kernels over time in the low-pressure treatment group provided in this application embodiment; Figure 9 A comparison chart showing the change in moisture content of almond kernels over time in the hydrogen short-time low-pressure fumigation treatment group provided in the embodiments of this application; Figure 10 A comparison chart showing the change in moisture content of almond kernels over time in the helium short-time low-pressure fumigation treatment group provided in the embodiments of this application; Figure 11 A comparison chart showing the change in moisture content of almond kernels over time in the composite gas short-time low-pressure fumigation treatment group provided in the embodiments of this application; Figure 12 A graph showing the change in iodine value of shelled almonds provided in the embodiments of this application; Figure 13 A graph showing the change in iodine value of shell-less almonds provided in an embodiment of this application; Figure 14 A graph showing the change in peroxide value of shelled almonds provided in an embodiment of this application; Figure 15 A graph showing the change in peroxide value of shell-less almonds provided in the embodiments of this application. Detailed Implementation

[0018] The following is in conjunction with the appendix Figure 1-15 The embodiments described herein provide a clear and complete explanation of the technical solutions presented. Obviously, the described embodiments are only a portion of, not all, of the embodiments presented herein. All other embodiments obtained by those skilled in the art based on the embodiments presented herein without inventive effort are within the scope of protection of this application.

[0019] The following description of some technologies involved in the embodiments of this application is provided to aid understanding and should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, some descriptions of well-known functions and structures are omitted in the following description.

[0020] The percentages in the embodiments of this application all refer to mass percentages, the raw and auxiliary materials involved are all purchased from conventional public channels, and the technical means used are all conventional methods in the field.

[0021] Appendix Figure 1-15All the embodiments in the examples were tested under accelerated storage conditions (40 °C & 80 %RH) to simulate extreme environmental conditions, accelerate the experimental process, and verify product performance.

[0022] Example 1: A low-pressure fumigation method using composite gases to extend the shelf life of almonds This application provides a low-pressure fumigation method using composite gases to extend the shelf life of almonds, comprising: The harvested almonds are dried to obtain dried almonds.

[0023] The dried almonds were packed into bags according to the preset loading weight.

[0024] The dried almonds, after being packaged and loaded, are placed in a low-pressure fumigation chamber, and the pressure of the chamber is adjusted to the preset target pressure range, which is lower than atmospheric pressure.

[0025] A composite gas is injected into a low-pressure fumigation chamber adjusted to a preset target pressure range to perform a short-term low-pressure fumigation treatment on dried almonds, resulting in dried almonds after short-term low-pressure fumigation treatment. The almonds are then sealed and stored at a temperature of 0 ℃ to 10 ℃. The composite gas contains at least one inert gas and one non-inert gas.

[0026] Example 2: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Lipids are the main component of almond kernels, accounting for more than 50% of the total weight. Of these, unsaturated fatty acids (mainly oleic acid and linoleic acid) account for approximately 90% of the total lipids, while saturated fatty acids are present in lower amounts, typically less than 10%. Studies have shown that long-term, moderate consumption of almonds helps regulate total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c) levels in the blood, which is beneficial for maintaining healthy blood lipids. In existing technologies, pretreatment methods such as heat treatment (e.g., roasting, heat bleaching) can improve the texture and flavor of almonds to some extent and inhibit some oxidation reactions. However, such treatments often result in the loss of phenolic antioxidants, and alterations to the microscopic lipid cell structure may affect their storage stability.

[0027] This application establishes a method to promote the penetration and distribution of fumigants in kernel tissues under low pressure, achieving multiple effects of antibacterial, insecticidal, and lipid oxidation inhibition at relatively low chemical doses. A blank control group (CK) without any treatment of almonds was set up for comparison.

[0028] The harvested almonds were dried using a hot air drying method to obtain dried almonds with a moisture content between 4% and 6%.

[0029] The dried almonds were placed in mesh bags measuring 30 cm × 40 cm; the preset loading weight was 5.00 kg ± 0.10 kg per bag.

[0030] In this embodiment, peeling and drying are utilized. Harvested almonds are dried to obtain dried almonds with a moisture content between 4% and 6%. Alternatively, those skilled in the art can also dry harvested almonds using methods such as hot air drying or heat pump drying. The dried almonds are categorized into shelled almonds and unshelled almonds. Dry almonds free from pests or mold are selected and packaged according to whether they are shelled or not.

[0031] The short-term low-pressure fumigation treatment lasts for 0.5 h to 8 h, and the temperature is 15 ℃ to 25 ℃.

[0032] Specifically, dried almonds are placed in a low-pressure fumigation chamber at room temperature (18 ℃~25 ℃). This application obtains a low-pressure fumigation chamber with a volume of 21 cubic meters by adding a gas mixer to an existing low-pressure fumigation device.

[0033] The composite gas is mixed using a gas mixer; the composite gas consists of hydrogen and helium. The concentrations of the composite gas are as follows: hydrogen concentration is 25 μL / L to 40 μL / L, and helium concentration is 15 μL / L to 100 μL / L.

[0034] In one possible implementation, those skilled in the art can select gases other than helium, such as neon, argon, krypton, and xenon, as inert gas components in the composite gas.

[0035] Specifically, in order to achieve safe injection of hydrogen and helium, the low-pressure fumigation chamber of this application can agitate the composite gas through a gas mixer during the low-pressure fumigation process, and through a gas circulation system, such as a fan, make the composite gas evenly distributed in the low-pressure fumigation chamber, thereby improving fumigation efficiency.

[0036] The vacuum system reduces the pressure inside the low-pressure fumigation chamber to a preset target pressure range of 0.5 kPa to 5 kPa.

[0037] The short-term low-pressure fumigation treatment lasts for 0.5 h to 8 h, and the temperature is 15 ℃ to 25 ℃.

[0038] In this embodiment, the pressure inside the low-pressure fumigation chamber is adjusted to 2 MPa. Hydrogen (30 μL / L) and helium (50 μL / L) are mixed in a gas mixer and then injected into the low-pressure fumigation chamber for short-term low-pressure fumigation treatment, which lasts for 1.5 hours. After the short-term low-pressure fumigation treatment is completed, the pressure relief valve is opened to slowly release the pressure, and the dried almonds after low-pressure fumigation with the composite gas are taken out.

[0039] Hydrogen plays a role in inhibiting mold growth and lipid oxidation during short-term low-pressure fumigation, while helium has shown good preservation effects on almond quality in previous experiments. Furthermore, as an inert gas, helium optimizes gas diffusion kinetics in a low-pressure environment and reduces the risk of hydrogen combustion, improving operational safety. The core principle of low-pressure fumigation technology lies in using a negative pressure environment to alter the fluid dynamics of the fumigation gas. When the pressure inside the chamber decreases to a specific range, the Reynolds number of the gas flow increases; once it exceeds a critical value, the flow pattern changes from laminar to turbulent, increasing the gas diffusion coefficient and penetration capacity. This promotes rapid and uniform distribution of the composite gas involved in fumigation in three-dimensional space, effectively enhancing its penetration into the almond kernel tissue. This process not only improves fumigation efficiency but also significantly inhibits mold growth and lipid oxidation reactions during almond storage.

[0040] like Figure 6 The image shown is a comparison of the morphology of almonds without shells and with shells on day 14 after the composite gas short-time low-pressure fumigation treatment group provided in the embodiments of this application. Figure 11 A comparison chart showing the change in moisture content of almond kernels over time in the composite gas short-time low-pressure fumigation treatment group provided in the embodiments of this application.

[0041] After undergoing short-term low-pressure fumigation, dried almonds are placed in PET bags and sealed for storage in a light-proof and oxygen-proof environment.

[0042] In this embodiment, the storage temperature is <10 ℃. The preferred storage temperature is 0 ℃ to 4 ℃, and a more preferred storage temperature is 0 ℃. This application, through the synergistic effect of a low-pressure environment and composite gas, significantly improves the commercial quality and storage stability of almonds while reducing gas consumption and shortening processing time, providing an efficient, safe, and environmentally friendly technical solution for the commercial preservation of almonds.

[0043] Example 3: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method for extending the shelf life of almonds using a composite gas, similar to Example 2, the only difference being that the mixed gas is set as a single non-inert gas. Hydrogen (30 μL / L) and helium (50 μL / L) are combined to form hydrogen (25 μL / L).

[0044] Example 4: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method using a composite gas to extend the shelf life of almonds, similar to Example 2, the only difference being that the mixed gas is set as a single non-inert gas. Hydrogen (30 μL / L) and helium (50 μL / L) are combined and set as hydrogen (30 μL / L). Figure 4 The image shown is a morphological diagram of almonds on day 14 of the hydrogen short-time low-pressure fumigation treatment group provided in the embodiments of this application. Figure 9 A comparison chart showing the change in moisture content of almond kernels over time in the hydrogen short-time low-pressure fumigation treatment group provided in the embodiments of this application.

[0045] Example 5: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method for extending the shelf life of almonds using a composite gas, similar to Example 2, the only difference being that the mixed gas is set as a single non-inert gas. Hydrogen (30 μL / L) and helium (50 μL / L) are combined to form hydrogen (40 μL / L).

[0046] Example 6: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method for extending the shelf life of almonds using a composite gas, similar to Example 2, the only difference being that the mixed gas is set to a single inert gas. Hydrogen (30 μL / L) and helium (50 μL / L) are replaced with helium (15 μL / L).

[0047] Example 7: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method using a composite gas to extend the shelf life of almonds, similar to Example 2, the only difference being that the mixed gas is set to a single inert gas. Hydrogen (30 μL / L) and helium (50 μL / L) are combined and replaced with helium (50 μL / L). Figure 5 The image shown is a morphological diagram of almonds on day 14 of the helium short-time low-pressure fumigation treatment group provided in this application embodiment. Figure 10 A comparison chart showing the change in moisture content of almond kernels over time in the helium short-time low-pressure fumigation treatment group provided in the embodiments of this application.

[0048] Example 8: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method for extending the shelf life of almonds using a composite gas, similar to Example 2, the only difference being that the mixed gas is set to a single inert gas. Hydrogen (30 μL / L) and helium (50 μL / L) are replaced with helium (100 μL / L).

[0049] Example 9: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method for extending the shelf life of almonds using a composite gas, similar to Example 2, the only difference being that the concentration of the mixed gas is set to hydrogen (40 μL / L) and helium (100 μL / L).

[0050] Example 10: A low-pressure fumigation method using composite gases to extend the shelf life of almonds Based on the description in Example 2, this application also provides a low-pressure fumigation method for extending the shelf life of almonds using a composite gas, similar to Example 2, the only difference being that the concentration of the mixed gas is set to hydrogen (25 μL / L) and helium (15 μL / L).

[0051] Comparative Example 1 A composite gas low-pressure fumigation method for extending the shelf life of almonds, similar to Example 2, differs in that the mixed gas used in short-term low-pressure fumigation is replaced with air. For example... Figure 8 The figure shown is a comparison of the change in moisture content of almond kernels over time in the low-pressure treatment group provided in this application.

[0052] Application Example 1 This application provides an application of a composite gas low-pressure fumigation method in extending the shelf life of almonds. Specifically, high-quality almonds from Shache region were purchased on September 10, 2025, with an initial moisture content of less than 4% to 6% after drying. Whole almonds (including both shelled and dehulled types) free from mold and pests were selected and treated according to the methods provided in Examples 2, 4, 7, and Comparative Example 1. To accelerate the mold growth and lipid oxidation process, all treatment groups were subjected to accelerated storage experiments at 40°C and 80% RH.

[0053] like Figure 1 and Figure 2 Morphological images of almonds on day 0 and day 14 of the blank control group provided in this application. Figure 3 Morphological diagram of almonds on day 14 of the low-pressure treatment group provided in this application. Figure 7 This is a comparison chart showing the change in moisture content of almond kernels over time in a blank control group provided in this application embodiment. Figures 7-11In the figure, the horizontal axis represents the time of the experiment in days (d), and the vertical axis represents the moisture content of almonds with and without shells, expressed as a percentage (%). Figure 12-13 The graph shows the changes in iodine value of almonds with and without shells provided in the embodiments of this application. The horizontal axis represents the time of the experiment, and the vertical axis represents the iodine content of almonds with and without shells. The unit is g / 100g. Figure 14-15 The graph shows the changes in peroxide value of almonds with and without shells, as provided in the embodiments of this application. The horizontal axis represents the time of the experiment, and the vertical axis represents the peroxide value of almonds with and without shells, with the unit being mEq / kg.

[0054] From the start of the experiment, samples were taken every two days to observe the appearance changes (moldy growth) of almonds in different treatment groups, and to measure key indicators such as moisture content, iodine value, and peroxide value. Table 1 shows the mold growth rate of different treatment groups, where CK represents the blank control group and LP represents the low-pressure treatment group. He represents the hydrogen short-time low-pressure fumigation treatment group, He represents the helium short-time low-pressure fumigation treatment group, MIX represents the mixed gas short-time low-pressure fumigation treatment group, and d represents the number of days. See the table below for details: Table 1: Mold Growth Rate of Different Treatment Groups In terms of mold control, conventional methods mainly rely on low water activity (Aw < 0.65) and low temperature conditions in the storage environment to inhibit mold growth, or use food-grade antifungal agents for surface treatment. However, these chemical methods may bring potential risks of residues and flavor contamination. Regarding storage environment control, low temperature (e.g., 0 °C - 4 °C), low humidity (RH < 65%), and oxygen-barrier packaging are commonly used to delay mold growth and lipid oxidation. However, existing methods mostly focus on the macroscopic control of external conditions, and a systematic explanation is still lacking regarding the dynamic evolution of lipid oxidation in almonds under the coupled effects of different water activities, gas components, and temperatures, especially the interaction mechanism between enzymatic and non-enzymatic oxidation, and the physiological response mechanism of molds in different gaseous microenvironments. Furthermore, traditional methods struggle to achieve the leap from "preservation" to "quality assurance."

[0055] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application 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 this application.

Claims

1. A low-pressure fumigation method using composite gases to extend the shelf life of almonds, characterized in that, include: The harvested almonds are dried to obtain dried almonds. The dried almonds are packed into bags according to a preset loading weight; The dried almonds, after being packaged and loaded, are placed in a low-pressure fumigation chamber, and the pressure of the low-pressure fumigation chamber is adjusted to a preset target pressure range; wherein, the preset target pressure range is lower than atmospheric pressure. The composite gas is injected into the low-pressure fumigation chamber adjusted to the preset target pressure range to perform short-term low-pressure fumigation treatment on the dried almonds, and the dried almonds after short-term low-pressure fumigation treatment are obtained and sealed for storage at a storage temperature of 0 ℃~10 ℃; wherein, the composite gas contains at least one inert gas and one non-inert gas.

2. The method according to claim 1, characterized in that, The process of drying harvested almonds to obtain dried almonds includes: The harvested almonds were dried using hot air drying to obtain dried almonds with a moisture content between 4% and 6%.

3. The method according to claim 1, characterized in that, The step of loading the dried almonds into bags according to a preset loading weight includes: The dried almonds were placed in a mesh bag; The preset loading weight is 5.00 kg ± 0.10 kg per bag for separate bagging.

4. The method according to claim 1, characterized in that, Before injecting the composite gas into the low-pressure fumigation chamber adjusted to the preset target pressure range, the method further includes: The composite gas is mixed using a gas mixer; wherein the composite gas consists of hydrogen and helium.

5. The method according to claim 4, characterized in that, The concentration of the composite gas includes: hydrogen concentration of 25 μL / L to 40 μL / L and helium concentration of 15 μL / L to 100 μL / L.

6. The method according to claim 1, characterized in that, Adjusting the pressure value of the low-pressure fumigation chamber to a preset target pressure range includes: The pressure inside the low-pressure fumigation chamber is reduced to the preset target pressure range of 0.5 kPa to 5 kPa by a vacuum system.

7. The method according to claim 1, characterized in that, The short-time low-pressure fumigation treatment of the dried almonds includes: The short-time low-pressure fumigation treatment lasts for 0.5 h to 8 h, and the temperature is 15 ℃ to 25 ℃.

8. The method according to claim 1, characterized in that, The process of obtaining the dried almonds after short-term low-pressure fumigation treatment and then sealing and storing them includes: The dried almonds, after undergoing short-term low-pressure fumigation, are placed in PET bags and sealed for storage in a light-proof and oxygen-proof environment.

9. The application of the composite gas low-pressure fumigation method as described in any one of claims 1 to 8 in extending the shelf life of almonds.

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