Test method for the effect of different packaging materials on the browning quality of sour beans

Abstract

The present application provides a test method for the effect of different packaging materials on the browning quality of sour beans, which belongs to the technical field of sour bean detection. This study selected 4 transparent packaging that meets food requirements as the research object, and used opaque packaging as the control. The sour beans were made by artificial inoculation, and modern analytical methods were used to measure and analyze the quality indicators such as color, browning degree, amino nitrogen content, VC content, and polyphenol content during natural preservation. The diversified detection items can reduce deviations, provide an effective basis for screening out the best transparent packaging materials, and provide experimental data for transparent packaging technology and quality control of sour beans.

Description

Technical Field

[0001] The invention relates to the technical field of sour bean detection, and in particular to a method for testing the influence of different packaging materials on the browning quality of sour beans. Background Art

[0002] Sour beans are a kind of pickled pickles, which refers to vegetable fermented products formed by lactic acid bacteria fermentation under low salt concentration conditions. It is one of the typical representatives of my country's traditional fermented foods. It has a strong sour taste and a crisp taste. It can promote appetite and help digestion. It is deeply loved by people and has become a unique delicacy that is not restricted by region and season. Sour beans are very prone to browning when stored under natural conditions. Although vacuum packaging can alleviate this problem, due to the influence of environmental factors, the browning of sour beans in the later stage of storage is still very serious. The storage period is very short, which seriously affects the healthy development of the sour bean industry. Many studies have confirmed that the browning of sour beans may be related to the oxidative decomposition of ascorbic acid, the oxidative polymerization of phenols and the Maillard reaction. However, there are relatively few studies on the regulation technology of sour beans browning. GB2760-2014 "Hygiene Standards for the Use of Food Additives" stipulates that any additives are strictly prohibited in pickled products such as sour beans. Therefore, choosing appropriate packaging has become the key to inhibiting the browning of sour beans;

[0003] Packaging materials have certain barrier properties, which can prevent the loss of water, reduce the penetration of external oxygen, and block, reflect and scatter light, which can protect food to a certain extent. There are many kinds of packaging materials, among which film packaging has certain heat sealing properties and can be vacuumed, and is widely used in various foods. However, the materials of film packaging are different, and the parameters such as light transmittance, air permeability, thickness, etc. are different, and the protective effect on food is also different. By testing the effect of different packaging materials on the browning quality of sour beans, we can select the appropriate packaging materials, but the traditional testing items are relatively single, which can easily mislead the selection of packaging materials and affect the packaging effect. Therefore, we have made improvements to this and proposed a test method for the effect of different packaging materials on the browning quality of sour beans. Summary of the invention

[0004] The purpose of the present invention is to address the problem that the existing testing items are relatively single, which can easily mislead the selection of packaging materials and thus affect the packaging effect.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A test method for the effect of different packaging materials on the browning quality of sour beans is developed to improve the above problems.

[0007] The specific application is as follows:

[0008] The following steps are involved:

[0009] S1. Material selection: Choose sour beans and different types of packaging bags with different oxygen permeability, including opaque polyamide / aluminum / polyethylene packaging bags, translucent polyethylene terephthalate / polyethylene packaging bags, polyamide / cast polypropylene film packaging bags, PA / CPE packaging bags and PET / PA / RCPP packaging bags. According to GB / T1038-2000 Test method for gas permeability of plastic film and sheeting - pressure difference method, measure the relevant parameters of the packaging bags;

[0010] S2. Select experimental reagents: formaldehyde, oxalic acid, anhydrous sodium carbonate, sodium hydroxide, ascorbic acid and glucose;

[0011] S3. Select instruments and equipment: The instruments and equipment include 722-P visible spectrophotometer, UtraScan Pro colorimeter, Sartorius acidity meter, HH-6 digital constant temperature water bath, C640 thickness gauge, WGT-S transmittance haze meter, OX2 / 230 oxygen permeability meter;

[0012] S4. Sample preparation: Weigh the pickled sour beans into bags, seal them, and store them under natural light. Take samples every 30 days, grind each bag into pulp, and test various indicators.

[0013] S5. Browning degree test: using the extinction value method, add ice-cold distilled water to the sour bean slurry, homogenize and keep warm in a water bath to make a sample solution, measure the absorbance of the sample solution at a wavelength of 410nm, and use 10:A410 to represent the browning degree;

[0014] S6. Color test: The color parameters obtained by using a colorimeter are L*, a* and b* values;

[0015] S7. Test of total phenol content: The total phenol content in the sour bean slurry was tested by the Folin phenol method;

[0016] S8. Testing of reducing sugar content: using 3,5-diphenylsalicylic acid method to test the reducing sugar content in the sour bean slurry;

[0017] S9. Test of amino nitrogen content: The amino nitrogen content in the sour bean slurry is tested by formaldehyde titration method;

[0018] S10. Testing of VC content: The VC content in the sour bean slurry was tested by fluorescence method and 2,4-dihydrophenylhydrazine method;

[0019] S11. Experimental data processing method: All index tests were repeated 3 times, with 3 parallels each time, and data analysis was performed using SPSS22.0 one-way ANOVA to perform significant difference analysis.

[0020] As a preferred technical solution of the present application, the opaque polyamide / aluminum / polyethylene packaging bag in step S1 is used as a control group, and the rest are used as experimental groups.

[0021] As a preferred technical solution of the present application, the purity of glucose in the step S2 is greater than 98%.

[0022] As a preferred technical solution of the present application, the weight of each bag of sour beans in step S4 is 100 g.

[0023] As a preferred technical solution of the present application, in the step S4, a sealing and disinfecting device is used to seal and disinfect the packaging bag, and the sealing method is vacuum sealing.

[0024] As a preferred technical solution of the present application, in the step S4, a grinding and filtering device is used to grind and filter at the same time to grind the sample into a slurry.

[0025] As a preferred technical solution of the present application, the amount of ice-cold distilled water added in step S5 is 100 ml, and the homogenization time is 40 s.

[0026] As a preferred technical solution of the present application, the water bath temperature in step S5 is 25°C.

[0027] As a preferred technical solution of the present application, in step S6, L* represents the brightness axis, 0 represents black, and 100 represents white;

[0028] a* represents the red-green axis, positive values ​​represent red, and negative values ​​represent green;

[0029] b* represents the yellow-blue axis, with positive values ​​representing yellow and negative values ​​representing blue.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] In the scheme of this application:

[0032] In this study, four types of transparent packaging that meet food requirements were selected as the research objects, and opaque packaging was used as the control. Sour beans were made according to the artificial inoculation method, and modern analytical methods were used to measure and analyze the quality indicators such as color, browning degree, amino nitrogen content, VC content, and polyphenol content during the natural preservation process. The diversification of detection items can reduce deviations, provide an effective basis for screening out the best transparent packaging material, and provide experimental data for transparent packaging technology and quality control of sour beans. DETAILED DESCRIPTION

[0033] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0034] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the invention product is usually placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0038] Embodiment 1:

[0039] This embodiment proposes a test method for the effect of different packaging materials on the browning quality of sour beans, comprising the following steps:

[0040] S1. Material selection: Select sour beans and different types of packaging bags with different oxygen permeability, including opaque polyamide / aluminum / polyethylene packaging bags, translucent polyethylene terephthalate / polyethylene packaging bags, polyamide / cast polypropylene film packaging bags, PA / CPE packaging bags and PET / PA / RCPP packaging bags. According to GB / T1038-2000 Plastic Film and Sheet Gas Permeability Test Method Pressure Difference Method, the relevant parameters of the packaging bags are measured, as shown in Table 1:

[0041]

[0042] S2. Select experimental reagents: formaldehyde, oxalic acid, anhydrous sodium carbonate, sodium hydroxide, ascorbic acid and glucose;

[0043] S3. Select instruments and equipment: The instruments and equipment include 722-P visible spectrophotometer, UtraScan Pro colorimeter, Sartorius acidity meter, HH-6 digital constant temperature water bath, C640 thickness gauge, WGT-S transmittance haze meter, OX2 / 230 oxygen permeability meter;

[0044] S4. Sample preparation: Weigh the pickled sour beans into bags, seal them, and store them under natural light. Take samples every 30 days, grind each bag into pulp, and test various indicators.

[0045] S5. Browning degree test: using the extinction value method, add ice-cold distilled water to the sour bean slurry, homogenize and keep warm in a water bath to make a sample solution, measure the absorbance of the sample solution at a wavelength of 410nm, and use 10:A410 to represent the browning degree;

[0046] S6. Color test: The color parameters obtained by using a colorimeter are L*, a* and b* values;

[0047] S7. Test of total phenol content: The total phenol content in the sour bean slurry was tested by the Folin phenol method;

[0048] S8. Testing of reducing sugar content: using 3,5-diphenylsalicylic acid method to test the reducing sugar content in the sour bean slurry;

[0049] S9. Test of amino nitrogen content: The amino nitrogen content in the sour bean slurry is tested by formaldehyde titration method;

[0050] S10. Testing of VC content: The VC content in the sour bean slurry was tested by fluorescence method and 2,4-dihydrophenylhydrazine method;

[0051] S11. Experimental data processing method: All index tests were repeated 3 times, with 3 parallels each time, and data analysis was performed using SPSS22.0 one-way ANOVA to perform significant difference analysis.

[0052] As a preferred embodiment, on the basis of the above method, further, the opaque polyamide / aluminum / polyethylene packaging bag in step S1 is used as a control group, and the rest are used as experimental groups, polyamide / aluminum / polyethylene packaging bags, namely PET / AL / PE, translucent polyethylene terephthalate / polyethylene packaging bags, namely PET / PE, and polyamide / cast polypropylene film packaging bags, namely PA / RCPP.

[0053] As a preferred embodiment, based on the above-mentioned method, further, the purity of glucose in step S2 is greater than 98%.

[0054] As a preferred embodiment, based on the above method, further, in step S4, the weight of each bag of sour beans is 100 g.

[0055] As a preferred implementation, based on the above-mentioned method, further, in step S4, a sealing and disinfecting device is used to seal and disinfect the packaging bag, and the sealing method is vacuum sealing.

[0056] As a preferred embodiment, based on the above method, further, in step S4, a grinding and filtering device is used to grind and filter at the same time to grind the sample into a slurry.

[0057] As a preferred embodiment, based on the above method, further, in step S5, the amount of ice-cold distilled water added is 100 ml, and the homogenization time is 40 s.

[0058] As a preferred embodiment, based on the above method, further, the water bath temperature in step S5 is 25°C.

[0059] As a preferred embodiment, based on the above method, further, in step S6, L* represents the brightness axis, 0 represents black, and 100 represents white;

[0060] a* represents the red-green axis, positive values ​​represent red, and negative values ​​represent green;

[0061] b* represents the yellow-blue axis, with positive values ​​representing yellow and negative values ​​representing blue.

[0062] Embodiment 2:

[0063] The solution in Example 1 is further introduced below in combination with a specific working method, as described below:

[0064] 1. Effect on browning degree of sour beans:

[0065] As shown in the figure below, the browning degree of the sour beans in each group showed an upward trend. Among them, the browning degree of the sour beans in the PET / PA / RCPP packaging group remained the lowest. The browning degree of the PA / RCPP packaging group was consistent with the control. The browning degree of the PA / CPE and PET / PE packaging groups was significantly higher than the control during the entire storage period (P<0.05). Therefore, the order of the inhibitory effect of each packaging group on the browning of sour beans from large to small is: PET / PA / RCPP>control=PA / RCPP>PA / CPE=PET / PE;

[0066]

[0067] Note: a, b, c are vertical deviations (P<0.05). The figure shows the effect of different packaging bags on the browning degree of sour beans during storage (n=9).

[0068] 2. Impact on the color of sour beans:

[0069] The L value indicates the brightness. During the entire storage period, the L value of the sour beans showed a downward trend. The L value of the PET / PE bag group and the PET / PA / RCPP bag group decreased to a similar degree as the control, but the L value of the PET / PE bag group and the PA / CPE bag group decreased relatively more. In the late storage period, the brightness of the sour beans in the PET / PE bag group and the PA / CPE bag group was significantly lower than that in the control (P<0.05), indicating that the PET / PE and PA / CPE bags had a greater impact on the brightness of the sour beans at the end of storage.

[0070] The a* value indicates the red-green ratio. During storage, the a* value of sour beans gradually changes from green to red. The higher the redness, the higher the degree of browning. In the early stage of storage, the a* value of sour beans in each group did not change much, and the color tone was mainly green. After 60 days of storage, the a* values ​​of the PET / PE and PA / CPE groups were significantly lower than those of the control, indicating that the two packaging materials accelerated the change of the color tone of sour beans from green to red in the late storage period. After 120 days of storage, the a* values ​​of the PET / PE and PET / PA / RCPP groups were significantly lower than those of the control and the other two groups (P<0.05), indicating that the two packaging materials played a positive role in inhibiting the color tone of sour beans from turning red in the late storage period.

[0071] The b* value indicates the blue-yellow ratio. The b* value of the sour beans showed an upward trend during storage, indicating that the yellow tone of the sour beans dominated. Similar to a*, the difference in b* among the groups was not significant at the beginning of storage. However, as the storage time increased, the b* value of the PET / PE packaging bag group increased rapidly. At 120 days of storage, it far exceeded the other packaging bag groups, while the b* value of the PET / PA / RCPP packaging bag group increased slowly and was significantly lower than that of the control group, indicating that the PET / PA / RCP packaging bag can effectively inhibit the deepening of the yellow tone of the sour beans during storage. The specific results are shown in Table 2.

[0072] Table 2 Effect of different packaging bags on the color of tamarind during storage (n=3)

[0073]

[0074] Note: a, b, c are vertical deviations (P<0.05).

[0075] 3. Impact on total phenol content:

[0076] Phenolic substances can generate benzoquinone melanin through enzymatic reactions, and can also generate melanin through oxidative polymerization. As shown in the figure below, the total phenol content of sour beans in each packaging bag gradually decreased with the extension of storage time. The total phenol content of the PET / PE and PA / CPE packaging bag groups began to be significantly lower than that of other groups after 60 days of storage (P<0.05). The change in total phenol content in the PA / RCP packaging bag group was similar to that in the control group. The total phenol content in the PET / PA / RCPP packaging bag group remained the highest. The difference in the change of total phenol content in each group may be related to the high air permeability of the packaging bag. The higher the air permeability, the faster the total phenol content decreases.

[0077]

[0078] The figure above shows the effect of different packaging bags on the total phenol content of sour beans during storage (n=3). Note: a, b, c are vertical deviations (P<0.05).

[0079] 4. Impact on reducing sugar content:

[0080] Reducing sugar is one of the substrates of the Maillard reaction. The polymer product generated by its reaction with amino acids is a kind of melanin. As shown in the figure below, the reducing sugar content of each packaging bag group showed a downward trend during storage. Among them, the difference in changes between PET / PA / RCPP, PA / RCPP packaging bags and the control group was not obvious, indicating that light avoidance has no protective effect on reducing sugar. During the entire storage period, the reducing sugar content of the PET / PE packaging bag group and the PA / CPE packaging bag group decreased faster, indicating that the loss of reducing sugar in the sour beans in the two groups of packaging was relatively large during storage. This may be related to the occurrence of the Maillard reaction, or it may be related to the growth and metabolism of microorganisms, so it is necessary to further clarify the changes in the amino nitrogen content;

[0081]

[0082] Note: a, b, c are vertical deviations (P<0.05).

[0083] The figure above shows the effect of different packaging bags on the reducing sugar content of sour beans during storage (n=3).

[0084] 5. Impact on amino nitrogen content:

[0085] The determination of amino nitrogen can reflect the changes in amino acid content, and amino acid is another substrate of Maillard reaction. In the figure below, during storage, the changes in amino nitrogen content in each packaging bag group showed a downward trend, but the overall change trend was not obvious, and the difference between the groups was not obvious. Combined with the changes in reducing sugar, it shows that Maillard reaction is not the main type of browning of sour beans, and each packaging bag has a certain protective effect on amino nitrogen;

[0086]

[0087] Note: a, b, c are vertical deviations (P<0.05)

[0088] The figure above shows the effect of different packaging bags on the amino nitrogen content of sour beans during storage (n=3).

[0089] 6. Impact on VC content:

[0090] VC oxidative browning is a common phenomenon in fruit and vegetable products. As shown in the figure below, the VC content in the control group was the best during the entire storage period, which means that avoiding light is beneficial to protecting VC. The VC content in the PET / PA / RCP and PA / CP packaging bag groups decreased relatively slowly, but the VC content in the PET / PE packaging bag group decreased relatively quickly, and was significantly lower than that in the other four groups after 120 days of storage (P<0.05), indicating that packaging bags with high oxygen permeability are prone to VC oxidative decomposition reactions.

[0091]

[0092] Note: a, b, c are vertical deviations (P<0.05).

[0093] The figure above shows the effect of different packaging bags on the VC content of sour beans during storage (n=9).

[0094] Embodiment 3:

[0095] The schemes in Example 1 and Example 2 are further introduced below in combination with specific working methods, as described below for details:

[0096] Browning is a common discoloration phenomenon during food processing and storage. According to its occurrence mechanism, it can be divided into enzymatic browning and non-enzymatic browning. Enzymatic browning is a process in which phenols and tannins in fruits and vegetables undergo a series of complex changes under the action of oxidase to produce a yellow-brown product. Studies have shown that due to the limitation of acidic conditions, enzymatic browning is unlikely to occur in pickles and sour beans. Non-enzymatic browning is composed of four types of reactions: Maillard reaction, caramelization reaction, ascorbic acid oxidation and phenolic substance oxidation. Caramelization reaction requires high temperature, so it does not belong to the type of sour bean browning. In actual production, the effect of oxygen on browning is often indirectly reduced by changing the packaging method and the type of packaging material. However, the light-shielding degree and barrier property of the packaging material have different effects on non-enzymatic browning. Studies have found that sour beans packaged in opaque PET / A1 / PE vacuum packaging have the best gloss, soft yellow, and the lowest browning degree. However, this type of packaging hinders consumers from intuitively experiencing the product, which is easy to reduce the desire to buy and has high costs, and is not used in actual production applications.

[0097] This study studied the effects of five packaging materials with different light transmittance and air permeability on the browning quality of tamarind beans during storage, and found that PET / PA / RCPP had a positive effect on maintaining the luster of tamarind beans and reducing the browning degree, and its effect exceeded that of PET / AL / PE aluminized packaging bags. At the same time, it was found that the changes in the total phenol content of tamarind beans in each packaging bag group were consistent with the browning degree, indicating that the oxidative polymerization of phenolic substances was the dominant factor in the browning of tamarind beans during storage and was also a key factor that needed to be regulated. Judging from the changes in the content of amino nitrogen and reducing sugar, the Maillard reaction may have occurred in each packaging bag, but the difference in the effect on the browning of tamarind beans was not obvious. This indicates that different packaging materials have little effect on the Maillard reaction. The browning of sour beans is caused by the reaction of VC with ammonia substances. Lowering the temperature can prevent this reaction from happening. However, this study found that PET / AL / PE aluminized packaging bags can inhibit the decline of VC content, thereby reducing the degree of browning of sour beans. In comparison, PET / PA / RCPP packaging bags and PET / PE packaging bags do not have a prominent inhibitory effect on polyphenol oxidation and VC oxidation, while the inhibitory effects of PET / PE and PA / CPE packaging bags are relatively weak. However, in packaging bags with higher air permeability, VC and polyphenols in sour beans are more likely to undergo oxidation reactions.

[0098] The above research results show that the inhibitory effect of each packaging bag on the browning of sour beans is PET / PA / RCPP>control=PA / RCPP>PA / CPE=PET / PE, among which PET / PA / RCPP packaging bags significantly reduced the oxidative condensation of polyphenols (P<0.05), and PA / RCPP packaging bags significantly reduced the oxidative decomposition of VC (P<0.05). The effects of PET / PE and PA / CPE packaging bags on polyphenols and VC were not obvious, and the effects of each group of packaging bags on amino nitrogen and reducing sugars were not obvious. Taking all factors into consideration, PET / PA / RCPP packaging has a positive effect on inhibiting the browning of sour beans during storage.

[0099] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the above specific implementation methods. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the invention are included in the scope of the claims of the present invention.

Claims

1. A method for testing the effect of different packaging materials on the browning quality of sour beans, characterized in that: The following steps are involved: S1. Material selection: Choose sour beans and different types of packaging bags with different oxygen permeability, including opaque polyamide / aluminum / polyethylene packaging bags, translucent polyethylene terephthalate / polyethylene packaging bags, polyamide / cast polypropylene film packaging bags, PA / CPE packaging bags and PET / PA / RCPP packaging bags. According to GB / T1038-2000 Test method for gas permeability of plastic film and sheeting - pressure difference method, measure the relevant parameters of the packaging bags; S2. Select experimental reagents: formaldehyde, oxalic acid, anhydrous sodium carbonate, sodium hydroxide, ascorbic acid and glucose; S3. Select instruments and equipment: The instruments and equipment include 722-P visible spectrophotometer, UtraScan Pro colorimeter, Sartorius acidity meter, HH-6 digital constant temperature water bath, C640 thickness gauge, WGT-S transmittance haze meter, OX2 / 230 oxygen permeability meter; S4. Sample preparation: Weigh the pickled sour beans into bags, seal them, and store them under natural light. Take samples every 30 days, grind each bag into pulp, and test various indicators. S5. Browning degree test: using the extinction value method, add ice-cold distilled water to the sour bean slurry, homogenize and keep warm in a water bath to make a sample solution, measure the absorbance of the sample solution at a wavelength of 410nm, and use 10:A410 to represent the browning degree; S6. Color test: The color parameters obtained by using a colorimeter are L*, a* and b* values; S7. Test of total phenol content: The total phenol content in the sour bean slurry was tested by the Folin phenol method; S8. Testing of reducing sugar content: using 3,5-diphenylsalicylic acid method to test the reducing sugar content in the sour bean slurry; S9. Test of amino nitrogen content: The amino nitrogen content in the sour bean slurry is tested by formaldehyde titration method; S10. Testing of VC content: The VC content in the sour bean slurry was tested by fluorescence method and 2,4-dihydrophenylhydrazine method; S11. Experimental data processing method: All index tests were repeated 3 times, with 3 parallels each time, and data analysis was performed using SPSS22.0 one-way ANOVA to perform significant difference analysis.

2. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: The opaque polyamide / aluminum / polyethylene packaging bag in step S1 was used as a control group, and the rest were used as experimental groups.

3. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: The purity of glucose in step S2 is greater than 98%.

4. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: In step S4, each bag of sour beans weighs 100 g.

5. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: In the step S4, the packaging bag is sealed and disinfected by using a sealing and disinfecting device, and the sealing method is vacuum sealing.

6. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: In the step S4, a grinding and filtering device is used to grind and filter at the same time, and the sample is ground into a slurry.

7. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: In the step S5, the amount of ice-cold distilled water added is 100 ml, and the homogenization time is 40 s.

8. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: The water bath temperature in step S5 is 25°C.

9. The method for testing the effect of different packaging materials on the browning quality of sour beans according to claim 1, characterized in that: In step S6, L* represents the brightness axis, 0 represents black, and 100 represents white; a* represents the red-green axis, positive values ​​represent red, and negative values ​​represent green; b* represents the yellow-blue axis, with positive values ​​representing yellow and negative values ​​representing blue.

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