Method for preventing mung bean canning browning under high temperature and high pressure

Abstract

The application provides a color protection agent for preventing mung bean cans from browning and a method for preventing mung bean cans from browning, and the color protection agent comprises the following components in terms of mass fraction: 0.05-0.08% of citric acid, 0.005-0.015% of amino acid, and the balance of water. The color protection agent is applied to preventing mung bean cans from browning under high temperature and high pressure. The mung beans do not need to be precooked before production, the water consumption is reduced, the production process is simplified, and the production efficiency is improved. The mung bean cans produced by the application are still bright green in color after being opened within 2 years of shelf life, and the soup is clear and transparent, which meets the conventional understanding of Chinese consumers on mung bean products.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically a method for preventing browning of canned mung beans under high temperature and high pressure. Background Technology

[0002] During the prolonged high-temperature and high-pressure sterilization process (121℃ / 20-30 minutes), the chlorophyll in the mung bean skin is unstable, causing the color of the canned mung beans to turn yellow or yellowish-brown due to chlorophyll degradation. Furthermore, as the storage time of canned foods increases (usually after 2-3 months), the chlorophyll degradation products further degrade / oxidize, producing red substances, resulting in the canned mung beans appearing entirely red. This can easily mislead consumers into thinking it's a red bean product, thus losing its distinctive characteristics and seriously affecting product quality and the development of the canned mung bean industry (Chen Shuanhu and Gao Shengli, eds. Comprehensive Utilization and Deep Processing Technology of Agricultural and Sideline Products - Grains and Legumes [M], 2003, Shaanxi Science and Technology Press, 176-177). Therefore, solving the problem of chlorophyll degradation during the processing of mung bean products is crucial for the preparation of canned mung bean products.

[0003] Chlorophyll, as a major photosynthetic pigment, is widely distributed in green fruits and vegetables, playing a crucial role in the color of green plants. However, chlorophyll is easily degraded during processing, leading to changes in the color of food. The chlorophyll molecule consists of two parts: a porphyrin ring and phytol with a long aliphatic hydrocarbon side chain. Four pyrrole rings are connected to a methine (=CH-) to form a large porphyrin ring. The magnesium atom is located at the center of the large porphyrin ring, tending to be positively charged, while the nitrogen atom attached to it tends to be negatively charged. There is also a carbon-containing side ring (E), and a carbonyl group and a carboxyl group are attached to the outside of the ring.

[0004] Studies have shown that common color-protecting agents include acidic color-protecting agents, reducing agents, chelating agents, and ionic compounds, which achieve color protection by inhibiting browning. Zhang Guozhi (Zhang Guozhi, Zhang Yun, Zhang Yu. Study on color protection of green wheat and mung bean steamed cake. Grain Processing, 2021, 46(3):14-18) et al. added a certain proportion of sodium copper chlorophyllin, sodium D-isoascorbate and citric acid to mung beans. The prepared mung bean steamed cake had a good wheat green color. However, the color-protecting agent contained synthetic pigments, which are subject to strict regulations and restrictions by national laws and regulations, posing certain safety hazards. Most existing technologies require the addition of artificial synthetic pigments, which increases the risk of food safety. Moreover, existing technologies have only studied the color stability of canned mung beans within 40 days, but the shelf life of canned foods is 2 years. Whether the color can continue to be stable during the later storage period has not been studied and explained. Summary of the Invention

[0005] This invention provides a method for preventing browning of canned mung beans under high temperature and high pressure. It mainly solves the problem of discoloration of canned mung bean products, which changes from green to red due to chlorophyll degradation during the high temperature and high pressure sterilization process and during the shelf life, and the resulting turbidity of the broth.

[0006] The technical solution of this invention is as follows:

[0007] A color-protecting agent to prevent browning in canned mung beans, said color-protecting agent comprising the following components by mass fraction:

[0008] Citric acid 0.05-0.08%, amino acids 0.005-0.015%, balance water.

[0009] Preferably, the color-protecting agent further comprises the following components in mass fractions:

[0010] The contents consist of 0.005-0.015% tea polyphenols and 0.0005-0.0015% lotus leaf extract, with the remainder being water.

[0011] More preferably, the color-protecting agent further comprises the following components by mass fraction:

[0012] Lotus leaf extract 0.0005-0.0015%.

[0013] More preferably, the amino acid is a basic amino acid, including lysine, arginine, histidine, or other or combinations thereof.

[0014] More preferably, the color-protecting agent comprises the following components by mass fraction:

[0015] Citric acid 0.07%, amino acids 0.01%, tea polyphenols 0.01%, and lotus leaf extract 0.001%, with the remainder being water.

[0016] The method for preparing the lotus leaf extract is as follows:

[0017] The method for preparing the lotus leaf extract is as follows: Weigh the washed tender green lotus leaves, place them in a pulping machine at a solid-liquid ratio of lotus leaf to water of 1:(2.5-3.5), add citric acid at 0.011-0.05% of the added water, crush the lotus leaves, extract at 45-50℃ for 0.8-1.5 hours, filter with gauze, and refrigerate for later use.

[0018] The color-protecting agent is used to prevent browning of canned mung beans under high temperature and high pressure.

[0019] Preferably, the high temperature and high pressure conditions are: sterilization treatment at 115-125℃ for 15-25 minutes after the canned food is placed in the cage.

[0020] Preferably, the application includes the following steps:

[0021] S1 Soaking: Remove mud and impurities from mung beans, rinse them with running water, soak them for 3-4 hours, and then drain the water.

[0022] S2 broth preparation: Dissolve color protectant and sugar in water, adjust the broth and bring to a boil;

[0023] S3 Empty Can Cleaning and Sterilization: Empty cans are rinsed with hot water at a temperature of 82°C or higher, and simultaneously sterilized by steam spraying.

[0024] S4 Filling and Sealing: Fill the cans with mung beans first according to the solid requirements, then add the soup base and seal the cans. The sealed cans must be sterilized within 1 hour.

[0025] S5 Sterilization and Cooling: After the canned goods are packed into cages, they are sterilized in a high-pressure autoclave. The temperature is raised for 20 minutes, kept at 121℃ for 20 minutes, and then cooled by back pressure for 10 minutes until the product temperature is below 38℃.

[0026] Complete the preparation of browning process for canned mung beans.

[0027] Preferably, in step S3: the empty can is rinsed with hot water at a temperature of 82°C or higher;

[0028] In step S4: the sealed canned goods are required to be sterilized within 1 hour;

[0029] In step S5: after the canned food is placed in the cage, it is sterilized in a high-pressure autoclave, heated for 15-25 minutes, sterilized at a constant temperature of 115-125℃ for 15-25 minutes, and cooled by back pressure for 10 minutes until the product temperature is below 38℃.

[0030] Preferably, in step S5: after the canned food is placed in the cage, it is sterilized in a high-pressure sterilizer, heated for 20 minutes, sterilized at a constant temperature of 121°C for 20 minutes, and cooled by back pressure for 10 minutes until the product temperature is below 38°C.

[0031] The beneficial effects of this invention are:

[0032] The additives used in this invention are all conventional food additives, and there are no safety hazards or risks.

[0033] In this invention, mung beans do not need to be pre-cooked before production, which reduces water consumption, simplifies the production process, and improves production efficiency.

[0034] The canned mung beans produced by this invention retain a bright green color after opening within a two-year shelf life, and the broth remains clear and transparent, which aligns with the common perception of mung bean products among Chinese consumers. Attached Figure Description

[0035] Figure 1 Product inspection diagram of Example 1;

[0036] Figure 2 Product inspection diagram of Example 2;

[0037] Figure 3 Product inspection diagram of Example 3;

[0038] Figure 4 Product inspection diagram of Example 4;

[0039] Figure 5 Product inspection diagram of Example 5. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field. Test methods in the following embodiments that do not specify specific experimental conditions are generally performed according to conventional experimental conditions or experimental conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the present invention can be obtained commercially or by conventional methods.

[0041] The preparation method of lotus leaf extract used in the examples and comparative examples is as follows: Weigh the washed tender green lotus leaves, place them in a pulping machine at a ratio of lotus leaf:water = 1:3, add citric acid at 0.01% of the added water, crush the lotus leaves, extract at 45°C for 1.0 hour, filter through four layers of gauze, and refrigerate for later use.

[0042] Example 1 (Optimal Solution)

[0043] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0044] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0045] (3) Soup preparation: Prepare the soup with an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, 0.001% lotus leaf extract and 20% white sugar, and bring to a boil; the amino acid is lysine.

[0046] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0047] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0048] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0049] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0050] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 1 .

[0051] The canned mung beans produced in this embodiment are light green in color after sterilization, and the broth is clear and not cloudy. Furthermore, the color remains light green during the shelf life, achieving the intended purpose.

[0052] Example 2: (Following the literature scheme)

[0053] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0054] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0055] (3) Soup preparation: Prepare the soup by mixing an aqueous solution containing 0.06% citric acid, 0.16% sodium D-isoascorbate, 0.021% disodium ethylenediaminetetraacetate and 20% white sugar and bringing it to a boil;

[0056] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0057] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0058] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0059] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0060] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 2 .

[0061] In this embodiment, the canned mung beans produced are initially yellowish-green after sterilization, and the broth is cloudy. After 7-30 days of storage, the color begins to turn yellowish-brown, and after 30-90 days, it turns light reddish-brown. After 180 days of storage, the color becomes almost entirely red. This is likely because during the high-temperature and high-pressure processing, chlorophyll undergoes dephytoncide and demagnesification reactions, producing yellowish-brown pheophytic acid. In the early stages of storage, the color-protecting agent has an antioxidant effect, preventing some of the pheophytic chlorophyll from oxidizing. However, in the later stages of storage, the natural degradation of vitamin C and other substances in the canned mung beans generates free radicals, which can induce further oxidative cleavage of pheophytic chlorophyll at C5 between pyrrole rings A and B, producing red chlorophyll metabolites, and the broth becomes even more cloudy.

[0062] Example 3

[0063] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0064] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0065] (3) Soup preparation: Prepare the soup with an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols and 20% white sugar and bring it to a boil; the amino acid is lysine.

[0066] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0067] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0068] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0069] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0070] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 3 .

[0071] Compared to the optimal color-protecting agent scheme, this embodiment lacks lotus leaf extract. The resulting canned mung beans, after sterilization, are pale yellow with a cloudy broth, indicating that chlorophyll may have partially undergone de-monomerization and demagnesiation reactions during processing. After 7-30 days of storage, the color begins to turn yellowish-brown, indicating that the chlorophyll has largely undergone demagnesiation. After 30-90 days of storage, the color turns reddish-brown, and even after 180 days of storage, the color remains reddish-brown. This is likely because, in the later stages of storage, the added amino acids and tea polyphenols consume dissolved oxygen in the can and partially inhibit the natural degradation of vitamin C, thus also inhibiting the formation of some red chlorophyll metabolites, but not completely suppressing the oxidative degradation reaction of chlorophyll.

[0072] Example 4

[0073] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0074] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0075] (3) Soup preparation: Prepare the soup with an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.001% lotus leaf extract and 20% white sugar and bring to a boil; the amino acid is lysine.

[0076] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0077] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0078] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0079] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0080] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 4 .

[0081] Compared to the optimal color-protecting agent scheme, this embodiment lacks tea polyphenols. The resulting canned mung beans are pale green after sterilization, and the broth is relatively clear. This indicates that during processing, the lotus leaf extract, containing alkaloids, lotus leaf flavonoids, citric acid, and oxalic acid, inhibits the demagnesiation reaction of chlorophyll. After 7-30 days of storage, the color begins to turn light yellow, indicating that partial demagnesiation of chlorophyll has begun again, and the broth becomes cloudy. After 30-90 days, and up to 180 days of storage, the color turns reddish-brown. This shows that in the later stages of storage, the added amino acids and lotus leaf extract consume dissolved oxygen in the can and inhibit the oxidative degradation reaction of chlorophyll, but they do not completely inhibit the demagnesiation reaction of chlorophyll.

[0082] Example 5

[0083] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0084] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0085] (3) Soup preparation: Prepare the soup by mixing an aqueous solution containing 0.07% citric acid, 0.01% tea polyphenols, 0.001% lotus leaf extract and 20% white sugar and bringing it to a boil.

[0086] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0087] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0088] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0089] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0090] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 5 .

[0091] Compared to the optimal color-protecting agent scheme, this embodiment lacks amino acids. The resulting canned mung beans are pale green after sterilization, with a relatively clear broth. After 7-90 days of storage, the color begins to turn yellow, indicating that chlorophyll is gradually undergoing demagnesiation, and the broth begins to become cloudy. After 90-180 days of storage, the color turns red. This suggests that in the later stages of storage, the added tea polyphenols and lotus leaf extract consumed dissolved oxygen in the can, but failed to inhibit the oxidative degradation of chlorophyll.

[0092] Example 6

[0093] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0094] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0095] (3) Soup preparation: Prepare the soup with an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, 0.001% lotus leaf extract and 20% white sugar, and bring to a boil; the amino acid is arginine.

[0096] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0097] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0098] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0099] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0100] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 1 .

[0101] The canned mung beans produced in this embodiment are light green in color after sterilization, and the broth is clear and not cloudy. Furthermore, the color remains light green during the shelf life, achieving the intended purpose.

[0102] Example 7

[0103] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0104] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0105] (3) Soup preparation: Prepare the soup with an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, 0.001% lotus leaf extract and 20% white sugar, and bring to a boil; the amino acid is histidine.

[0106] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0107] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0108] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0109] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0110] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 1 .

[0111] The canned mung beans produced in this embodiment are light green in color after sterilization, and the broth is clear and not cloudy. Furthermore, the color remains light green during the shelf life, achieving the intended purpose.

[0112] Example 8

[0113] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0114] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0115] (3) Soup preparation: Prepare the soup by mixing an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, 0.001% lotus leaf extract and 20% white sugar, and bring it to a boil; the amino acid is a combination of histidine and lysine in a mass ratio of 1:2.

[0116] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0117] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0118] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0119] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0120] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 1 .

[0121] The canned mung beans produced in this embodiment are light green in color after sterilization, and the broth is clear and not cloudy. Furthermore, the color remains light green during the shelf life, achieving the intended purpose.

[0122] Example 9

[0123] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0124] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0125] (3) Soup preparation: Prepare the soup by mixing an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, 0.001% lotus leaf extract and 20% white sugar, and bring it to a boil; the amino acid is a combination of lysine and arginine in a mass ratio of 0.5:1.

[0126] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0127] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0128] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0129] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0130] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 1 .

[0131] The canned mung beans produced in this embodiment are light green in color after sterilization, and the broth is clear and not cloudy. Furthermore, the color remains light green during the shelf life, achieving the intended purpose.

[0132] Example 10

[0133] (1) Raw material acceptance: Select high-quality mung beans with bright color and uniform particle size;

[0134] (2) Soaking: Remove mud, sand and impurities, rinse with running water and drain.

[0135] (3) Soup preparation: Prepare the soup by mixing an aqueous solution containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, 0.001% lotus leaf extract, and 20% white sugar, and bring it to a boil; the amino acid is a combination of histidine and arginine in a mass ratio of 1:2.

[0136] (4) Empty can cleaning and sterilization: The empty can is rinsed with hot water above 82°C and sterilized by steam spraying.

[0137] (5) Filling and sealing: Fill with mung beans at the standard of 18% dry beans, then fill with soup and seal.

[0138] (6) Sterilization and cooling: Sterilization is carried out using a high-pressure sterilizer. The temperature is raised for 20 minutes, and then kept at 121℃ for 20 minutes. The product temperature is then cooled down to below 38℃ under back pressure for 10 minutes.

[0139] (7) Inspection and warehousing: After sterilization, the canned goods should be placed at room temperature for more than 7 days. Check for any bulging or other phenomena, and then label and store them in the warehouse.

[0140] (8) Color inspection was conducted on canned mung beans stored for different periods after opening the cans. See Appendix for details. Figure 1 .

[0141] The canned mung beans produced in this embodiment are light green in color after sterilization, and the broth is clear and not cloudy. Furthermore, the color remains light green during the shelf life, achieving the intended purpose.

[0142] Based on Example 1 above, this invention also conducted optimization studies on different ratios of the main color-protecting agent components (amino acids, tea polyphenols, and lotus leaf extract) in the optimal solution, and performed sensory evaluation:

[0143] Based on Example 1, the ratio of amino acids, tea polyphenols, and lotus leaf extract was changed, while other aspects remained the same as in Example 1.

[0144] The sensory evaluation was conducted by a 20-person judging panel (including 2 experienced distributors, 5 professional R&D personnel, and 3 users of this product). The prepared mung bean canned products were evaluated according to their storage time. The scoring criteria are shown in Table 1, and the color-protecting agent ratio and scoring results are shown in Table 2.

[0145] Table 1 Sensory rating criteria

[0146]

[0147] Table 2 Sensory evaluation of different proportions of color-protecting agent components in canned mung beans

[0148]

[0149] As shown in Table 1, the sensory evaluation of the product containing 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, and 0.001% lotus leaf extract was the best. The beans and soup had uniform color, the beans were green, and the soup was clear.

[0150] The results of this optimization experiment show that the ratio of color-protecting agent components has a significant impact on the sensory score of the product, and that the interaction between the various color-protecting agents is necessary to form the optimal color protection solution.

[0151] The technical solutions of the present invention have been explained through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above specific embodiments to be implemented. Any improvements made by those skilled in the art based on the present invention, or equivalent substitutions for the materials selected in the present invention, fall within the scope of patent protection.

Claims

1. A method for preventing browning in canned mung beans, characterized in that, The method includes soaking mung beans, adding a color-protecting agent and sugar to prepare a broth, boiling it, cleaning and sterilizing empty cans, filling and sealing, high-temperature and high-pressure sterilization, and cooling treatment; the color-protecting agent includes the following components by mass fraction: citric acid 0.05-0.08%, amino acids 0.005-0.015%, tea polyphenols 0.005-0.015%, lotus leaf extract 0.0005-0.0015%, and the balance being water; The amino acid is selected from one or two of lysine, arginine, and histidine; The preparation method of the lotus leaf extract is as follows: Weigh the washed tender green lotus leaves, place them in a pulping machine according to the solid-liquid ratio of lotus leaf to water of 1:(2.5-3.5), add citric acid according to 0.011-0.05% of the added water, crush the lotus leaves, extract at 45-50℃ for 0.8-1.5 hours, filter with gauze, and refrigerate for later use. The conditions for high-temperature and high-pressure sterilization are as follows: after the canned food is placed in the cage, it is sterilized at 115-125℃ for 15-25 minutes.

2. The method for preventing browning of canned mung beans according to claim 1, characterized in that, The color-protecting agent comprises the following components by mass fraction: 0.07% citric acid, 0.01% amino acids, 0.01% tea polyphenols, and 0.001% lotus leaf extract, with the balance being water.

3. The method for preventing browning of canned mung beans according to claim 1, characterized in that, The method includes the following steps: S1 Soaking: Remove mud and impurities from mung beans, rinse them with running water, soak them for 3-4 hours, and then drain the water. S2 broth preparation: Dissolve color protectant and sugar in water, adjust the broth and bring to a boil; S3 Empty Can Cleaning and Sterilization: Empty cans are rinsed with hot water at a temperature of 82°C or higher, and simultaneously sterilized by steam spraying. S4 Filling and Sealing: Fill the cans with mung beans first according to the solid requirements, then add the soup base and seal the cans. The sealed cans must be sterilized within 1 hour. S5 Sterilization and Cooling: After the canned goods are packed into cages, they are sterilized in a high-pressure autoclave. The temperature is raised for 20 minutes, kept at 121℃ for 20 minutes, and then cooled by back pressure for 10 minutes until the product temperature is below 38℃.

Images