Color-protecting processing method for convenient green soy bean dish

Abstract

The invention relates to a green soy bean convenient dish color-protecting processing method, which comprises the following steps: selecting: selecting green soy beans with normal green color, and removing defective products; cleaning: removing foreign matters on the surfaces of the green soybeans; adding a color fixative for blanching: adding 2-3g / kg of food-grade sodium bicarbonate as the color fixative into boiling water according to the water consumption for blanching, and blanching for 2-3 minutes in the boiling water; cooling: adopting two-stage cooling, cooling for 3-5 minutes by using slightly acidic electrolyzed water at 0-4 DEG C, then cooling by using an ice-water mixture, and cooling the green soy beans to 10 DEG C or below within 20 minutes; seasoning: adding material juice which is pre-frozen to have ice crystals; and packaging. The color fixative is safe, compliant, simple in process, excellent in color protection effect and suitable for industrial production of convenient green soy bean dishes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food processing technology, and in particular to a method for protecting the color of soybean pods. BACKGROUND

[0002] Soybean pods, such as salted soybean pods, soybean pods in brine, and soybean pods in brine, belong to the category of pre-packaged instant dishes, and the color retention process needs to be paid attention to. The green color of soybean pods mainly comes from chlorophyll, but chlorophyll is chemically unstable and can easily undergo demetallization under heating or acidic conditions, forming demetallized chlorophyll, which causes the color to become dark, brown or black. In addition, enzymatic browning (such as the action of peroxidase and polyphenol oxidase) can also exacerbate color deterioration. Blanching is a common method to inactivate enzyme activity, but there are defects in the selection of color protection agents and cooling processes in the prior art.

[0003] Most existing soybean pod color protection methods use a combination of blanching and color protection agent compounding. For example, Sun Jincai et al. (Research on the blanching and color protection process of soybean pods) used blanching (100°C, 3 minutes) and added zinc acetate (0.06%) and ascorbic acid (0.14%) as color protection agents, but zinc acetate is not included in the "National Food Safety Standard for the Use of Food Additives" (GB 2760-2024), which poses a safety risk. Li Yali et al. (Response surface optimization of soybean blanching and color protection process) used ultrasonic waves combined with blanching (95°C, 90s) and a compounded color protection agent (ascorbic acid 0.15%, citric acid 0.11%, and L-cysteine 0.11%), but the use of L-cysteine is limited to flour treatment agents or synthetic flavorings in GB 2760-2024, which does not meet regulatory requirements. Zhang Yu et al. (Research on the blanching and processing technology of soybean pods in brine) showed that blanching (100°C, 2 minutes) can effectively inhibit polyphenol oxidase, but did not involve color protection agents and cooling processes. Patent application No. 201910613862.4 (Instant leisure soybean and its preparation process) uses a compounded color protection agent of citric acid, L-cysteine, and ascorbic acid, which also has the problem of L-cysteine violation.

[0004] In addition, the residual heat after blanching in the prior art can lead to microbial reproduction, exacerbating color change and product quality deterioration. Although slightly acidic electrolyzed water can be used for microbial control as a food disinfectant (referring to GB 14930.2-2025), the existing soybean pod color protection method does not combine it with the cooling process.

[0005] In summary, the existing soybean pod instant dish color protection method has the following problems: (1) The selection of color protection agents does not meet regulatory standards, with high potential safety risks; (2) The temperature is not reduced and the microorganisms are not eliminated in time after blanching, which is not conducive to color retention; (3) Color protection agents are complex to formulate and inconvenient to operate, which is not conducive to industrialization and promotion.

[0006] Therefore, there is an urgent need to develop a convenient cooking method for edamame that is safe in ingredients, simple in process, and has excellent color protection. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a color-protecting processing method for edamame in convenient dishes. This method is safe in ingredients, simple in formula, and maintains the color of edamame through synergistic color protection and cooling processes. It solves the problems of color deterioration caused by unsafe color-protecting agents and insufficient cooling processes in existing color-protecting methods for convenient edamame dishes.

[0008] The objective of this invention is achieved as follows: A method for preserving the color of edamame in convenient dishes, comprising the following: S1. Selection: Select edamame with a normal green color and remove defective products; S2. Cleaning: Remove foreign objects from the surface of the edamame; S3, Bleaching with color-protecting agent: Add food-grade sodium bicarbonate as a color-protecting agent to boiling water. Based on the amount of blanching water, add 2 to 3 grams of food-grade sodium bicarbonate per kilogram of blanching water, i.e., the amount of food-grade sodium bicarbonate used is 2-3 g / kg of water. Stir until it is completely dissolved. Heat the prepared color-protecting agent solution to boiling and maintain the boiling point. S4, Cooling: S4.1, First-stage cooling: Quickly remove the blanched edamame and immediately transfer them to a slightly acidic electrolytic water bath at a temperature of 0°C to 4°C to cool them down. S4.2, Second-stage cooling: After the first stage of cooling, the edamame beans are removed and quickly transferred to an ice-water mixture. The ice-water mixture is made by mixing ice made from reverse osmosis water with reverse osmosis water, and the edamame beans are cooled to below 10°C within 20 minutes. S5. Seasoning: Add the sauce that has been pre-frozen until it contains ice crystals.

[0009] Furthermore, step S3 also includes immersing the edamame washed in step S2 into boiling water before adding the color-protecting agent to ensure that the edamame is completely submerged.

[0010] Furthermore, step S3 also includes adding the color-protecting agent, keeping the water boiling, and blanching the edamame for 2 to 3 minutes; during this period, gently stirring to ensure the edamame is heated evenly.

[0011] Furthermore, in step S4.1, the effective chlorine concentration of the slightly acidic electrolyzed water in the slightly acidic electrolyzed water tank is controlled between 20 ppm and 30 ppm.

[0012] Furthermore, in step S4.1, the blanched edamame is soaked in a slightly acidic electrolytic water bath for 3 to 5 minutes.

[0013] Furthermore, the ice-water mixture described in step S4.2 is made by mixing ice blocks made from reverse osmosis water and reverse osmosis water in a 1:1 mass ratio in a cooling tank, with the temperature kept constant at 0°C.

[0014] Furthermore, step S5 also includes first draining the cooled edamame and then mixing it with the seasoning sauce; the seasoning sauce can be brine, brine or fermented brine.

[0015] Furthermore, the sauce in step S5 needs to be frozen in a cold storage at -18°C or below until a few ice crystals or ice cubes appear in the sauce.

[0016] Furthermore, it also includes step S6, packaging: The seasoned edamame and sauce are packaged together; the packaging material is a composite film bag or box that meets food hygiene standards.

[0017] Furthermore, it also includes step S7, commercially available: The packaged products are stored in a low-temperature cold storage at 0℃ to 4℃, and are transported and sold under these low-temperature conditions via cold chain.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a convenient color-protecting processing method for edamame dishes. It uses food-grade sodium bicarbonate as a color-protecting agent, providing an alkaline environment during blanching in boiling water to inhibit chlorophyll demagnesiation. After blanching, a two-stage cooling process is employed: first, slightly acidic electrolyzed water is used to reduce microorganisms, followed by rapid cooling with an ice-water mixture, synergistically maintaining the edamame's color. It has the following specific advantages: (1) High safety: Food-grade sodium bicarbonate is used as a color protectant, which complies with GB2760-2024 standard, is non-toxic and harmless, and replaces non-compliant color protectants such as zinc acetate and L-cysteine ​​in the existing technology.

[0019] (2) Excellent color protection effect: Through the synergistic effect of sodium bicarbonate providing an alkaline environment and secondary cooling process, chlorophyll demagnesiation and microbial growth are effectively inhibited. Edamame maintains a high hue angle during its shelf life (e.g., 7 days of modified atmosphere packaging and refrigeration), greatly improving the color protection effect.

[0020] (3) Simple process: The color-protecting agent is simple and does not require complex compounding. The operation is simple and conducive to industrialization.

[0021] (4) Microbial control: Use slightly acidic electrolyzed water for cooling to reduce microorganisms, lower the risk of spoilage, and extend shelf life. Attached Figure Description

[0022] Figure 1 These are actual photos comparing the color of edamame in Embodiment 1 and Comparative Example DB-1-1 of the present invention.

[0023] Figure 2 These are actual photos comparing the color of edamame in Example 1 and Comparative Example DB-1-2 of the present invention.

[0024] Figure 3 These are actual photos comparing the color of edamame in Example 1 and Comparative Example DB-2-1 of the present invention.

[0025] Figure 4 These are actual photos comparing the color of edamame in Example 1 and Comparative Example DB-2-2 of the present invention.

[0026] Figure 5 These are actual photos comparing the color of edamame in Example 1 and Comparative Example DB-2-3 of the present invention. Detailed Implementation

[0027] To better understand the technical solution of the present invention, a detailed description will be provided below in conjunction with relevant illustrations. It should be understood that the specific embodiments described below are not intended to limit the specific implementation of the technical solution of the present invention, but are merely possible implementations of the technical solution of the present invention. It should be noted that the descriptions of the positional relationships of the components herein, such as component A being located above component B, are based on the relative positions of the components in the illustrations and are not intended to limit the actual positional relationships of the components.

[0028] This invention relates to a method for preserving the color of edamame in convenient dishes, comprising the following: S1. Selection: Freshly harvested edamame are selected manually or mechanically to remove pods that are abnormal in color (such as yellowing or browning), shriveled, damaged, have disease or pest spots, or are not fully formed, to ensure that the edamame raw materials used for processing have consistent initial quality and bright green color.

[0029] S2. Washing: Place the selected edamame in running water or an air purifier for thorough washing. This step aims to remove dirt, sand, dust, pesticide residues, and plant impurities (such as straw and leaves) from the surface of the edamame. The washing time is usually 3-10 minutes, until the washing water is clear.

[0030] S3, Bleaching with color-protecting agent: S3.1 Preparation of color-protecting agent: Pour clean water that meets drinking water standards into a blanching tank or jacketed kettle, then add a color-protecting agent at a ratio of 2 to 3 grams of food-grade sodium bicarbonate (NaHCO3) per kilogram of water, and stir until completely dissolved.

[0031] S3.2, Blanching process: Heat the prepared color-protecting agent solution to boiling and maintain the boiling point; Put the edamame washed in step S2 into boiling water, making sure the edamame is completely submerged. Keep the water boiling and blanch the edamame for 2 to 3 minutes. During this time, you can stir it slightly to ensure that the edamame are heated evenly. This process inactivates peroxidase (POD) and polyphenol oxidase (PPO) through high temperature, while the weakly alkaline environment provided by sodium bicarbonate effectively inhibits the activity of magnesium ions (Mg²⁺) in chlorophyll molecules. + ) by hydrogen ions (H + The chlorophyll is replaced, thereby preventing the formation of pheophytin.

[0032] S4. Cooling: A two-stage cooling method is adopted to achieve rapid cooling and microbial control; S4.1, First-stage cooling (microbial reduction and initial cooling): After blanching, quickly remove the edamame and immediately transfer them to a slightly acidic electrolytic water bath at a temperature of 0°C to 4°C. The effective chlorine concentration of the slightly acidic electrolytic water in the bath should be controlled between 20 ppm and 30 ppm. Soak the edamame in this cooling medium for 3 to 5 minutes. This step utilizes low-temperature, slightly acidic electrolyzed water to quickly remove a large amount of heat from the edamame and uses its disinfection properties to significantly reduce the microorganisms remaining on the surface of the edamame.

[0033] S4.2, Second-stage cooling (deep cooling): After the first stage of cooling, the edamame beans are removed and quickly transferred to an ice-water mixture. The ice-water mixture is made by mixing ice made from reverse osmosis water (RO water) with reverse osmosis water (RO water) in a cooling tank at a mass ratio of 1:1, and the temperature is kept constant at 0°C. The edamame continues to cool in this ice-water mixture, ensuring that the core temperature of the edamame drops below 10°C within 20 minutes of the start of the entire cooling process; this step completely eliminates the effect of residual heat on color and quality.

[0034] S5, Seasoning: Drain the cooled edamame and then mix it with the seasoning sauce; The seasoning sauce can be brine, braising liquid, or fermented brine, etc. To help maintain a low temperature, the sauce needs to be frozen in a cold storage at -18°C or below until a few ice crystals or ice cubes appear in the sauce. During subsequent packaging and storage, these ice crystals will melt naturally, allowing the sauce to penetrate evenly and infuse the flavor.

[0035] S6. Packaging: The seasoned edamame and sauce are packaged together; Depending on product design and market demand, vacuum packaging or modified atmosphere packaging (such as filling with a mixture of nitrogen and carbon dioxide gas) can be used. Packaging materials should be composite film bags or boxes that meet food hygiene standards.

[0036] S7, retail available: The packaged products are stored in a low-temperature cold storage at 0℃ to 4℃, and are transported and sold under these low-temperature conditions via cold chain.

[0037] In a preferred embodiment, in step S3.1, the amount of food-grade sodium bicarbonate added is 2.5 grams per kilogram of blanching water.

[0038] In a preferred embodiment, the blanching time in step S3.2 is 2.5 minutes.

[0039] In a preferred embodiment, in step S4.1, the concentration of the slightly acidic electrolyzed water used for the first-stage cooling is 25 ppm.

[0040] In a preferred embodiment, in step S4.2, the goal of the second-stage cooling is to cool the edamame to below 8°C within 15 minutes.

[0041] Example 1 (named Scheme SS-1): 1. Raw material selection: Select 5 kg of fresh edamame from the market and manually remove pods that are yellow, have damaged skin, are shriveled, or have spots.

[0042] 2. Washing: Put the selected edamame into a bubble washing machine and wash with running water for 5 minutes until the water is clear.

[0043] 3. Blanching with color-protecting agent: Add 200 kg of drinking water to a jacketed kettle, weigh out 500 g of food-grade sodium bicarbonate (calculated concentration of 2.5 g / kg water), add it to the water, and stir to dissolve. Heat to boiling, add all the washed edamame, and blanch for 3 minutes while maintaining a boiling state, gently stirring twice during the process with a food-grade stirring paddle.

[0044] 4. Cooling: 4.1 First-stage cooling: Prepare a water tank containing slightly acidic electrolyzed water (30 ppm concentration) at 3°C. Quickly remove the blanched edamame with a slotted spoon and immerse them in the electrolyzed water for 5 minutes; 4.2 Second-stage cooling: Remove the edamame from the electrolyzed water and immediately transfer them to another cooling tank containing an ice-water mixture (ice and RO water are mixed at a 1:1 mass ratio). By monitoring with a thermometer inserted into the center of the edamame, the center temperature of the edamame dropped to 8.3℃ within 18 minutes.

[0045] 5. Seasoning: Drain the cooled edamame. Take the brine that has been frozen at -18℃ until it contains a small amount of ice crystals and mix it with the edamame in the correct proportion.

[0046] 6. Packaging: Pack the edamame and sauce together into a modified atmosphere packaging box, fill it with a mixture of nitrogen and carbon dioxide (7:3 ratio), and then seal it.

[0047] 7. Storage and Sales: The packaged products should be immediately placed in a cold storage at 0-4℃ and sold via cold chain at the same temperature.

[0048] Comparative Example 1 (color-protecting agent variable): (1) Name DB-1-1: Except for step S3, which does not add any color-protecting agent, the other steps are exactly the same as in Example 1.

[0049] (2) Name DB-1-2: Except for the addition of food-grade sodium bicarbonate in step S3, which is changed to 350 g / 200 kg water (calculated concentration is 1.75 g / kg water), the rest of the steps are exactly the same as in Example 1.

[0050] Comparative Example 2 (Cooling Process Variables): (1) Name DB-2-1: Except for step S4, in which the first stage of slightly acidic electrolyzed water cooling is cancelled and only the second stage of ice-water mixture cooling is performed, the rest of the steps are exactly the same as in Example 1.

[0051] (2) Named DB-2-2: Except for step S4, in which the second-stage ice-water mixture cooling is cancelled and only the first-stage slightly acidic electrolyzed water cooling is performed (the soaking time is extended to 10 minutes in an attempt to cool down), the rest of the steps are exactly the same as in Example 1.

[0052] (3) Name DB-2-3: Except for step S4, in which the entire secondary cooling process is cancelled and the blanched edamame is directly spread on a stainless steel tray to cool naturally at room temperature (about 25°C), the other steps are exactly the same as in Example 1.

[0053] Color evaluation method: (1) Hue Angle Measurement: Use a colorimeter to measure the L, a, and b values ​​of the edamame and calculate Hue Angle = tan⁻¹(b / a*); the larger the value, the greener the color.

[0054] (2) Real object shooting: Shoot with the same camera under the same environment and observe the color difference with the naked eye.

[0055] The color measurement results and analysis data of the products obtained in the above embodiments and comparative examples 1-2 are shown in Table 1 below:

[0056] Table 1: Color Measurement Results of Examples and Comparative Examples See Figures 1-5 , Figure 1 These are actual photographs comparing the color of edamame in Embodiment 1 and Comparative Example DB-1-1 of the present invention. Figure 2 These are actual photographs comparing the color of edamame in Example 1 and Comparative Example DB-1-2 of the present invention. Figure 3 These are actual photographs comparing the color of edamame in Example 1 and Comparative Example DB-2-1 of the present invention. Figure 4 These are actual photographs comparing the color of edamame in Example 1 and Comparative Example DB-2-2 of the present invention. Figure 5 These are actual photos comparing the color of edamame in Example 1 and Comparative Example DB-2-3 of the present invention.

[0057] From Table 1 and Figures 1-5 It can be seen that the edamame processed in Example 1 (SS-1) of this invention has a hue angle as high as 160.01, which is significantly better than all comparative examples, and the product can still maintain a bright green color after 7 days of refrigeration. The hue angle of this invention is the highest, and the color protection effect is the best. In the comparative examples, the lack of color protection agent or insufficient dosage, and the incomplete cooling process all led to color deterioration. Only when the color protection agent is added within the effective dosage range, and when a mixture of slightly acidic electrolyzed water and ice water is used for rapid secondary cooling, and when the sauce containing ice crystals (ice cubes) is used for flavoring, can the expected beneficial effect be achieved. The results verify the effectiveness and synergy of the color protection agent and cooling process of this invention.

[0058] Working principle: This invention provides a method for color-protecting edamame in convenient dishes. It uses food-grade sodium bicarbonate as a color-protecting agent, providing an alkaline environment during blanching in boiling water to inhibit chlorophyll demagnesiation. After blanching, a two-stage cooling process is employed: first, slightly acidic electrolyzed water is used to reduce microorganisms, followed by rapid cooling with an ice-water mixture, synergistically maintaining the edamame's color. The color-protecting agent of this invention is safe and compliant, the process is simple, and the color-protecting effect is excellent, making it suitable for the industrial production of convenient edamame dishes.

[0059] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. All technical solutions formed by equivalent transformations or substitutions fall within the scope of protection of the present invention.

Claims

1. A method for processing edamame for convenient food color protection, characterized in that, Includes the following: S1. Selection: Select edamame with a normal green color and remove defective products; S2. Cleaning: Remove foreign objects from the surface of the edamame; S3, Bleaching with color-protecting agent: Add food-grade sodium bicarbonate as a color-protecting agent to boiling water. Based on the amount of blanching water, add 2 to 3 grams of food-grade sodium bicarbonate per kilogram of blanching water, i.e., the amount of food-grade sodium bicarbonate used is 2-3 g / kg of water. Stir until it is completely dissolved. Heat the prepared color-protecting agent solution to boiling and maintain the boiling point. S4, Cooling: S4.1, First-stage cooling: Quickly remove the blanched edamame and immediately transfer them to a slightly acidic electrolytic water bath at a temperature of 0°C to 4°C to cool them down. S4.2, Second-stage cooling: After the first stage of cooling, the edamame beans are removed and quickly transferred to an ice-water mixture. The ice-water mixture is made by mixing ice made from reverse osmosis water with reverse osmosis water, and the edamame beans are cooled to below 10°C within 20 minutes. S5. Seasoning: Add the sauce that has been pre-frozen until it contains ice crystals.

2. The method for color protection processing of edamame for convenient dishes according to claim 1, characterized in that: Step S3 also includes immersing the edamame washed in step S2 into boiling water before adding the color-protecting agent, ensuring that the edamame is completely submerged.

3. The method for color protection processing of edamame for convenient dishes according to claim 1, characterized in that: Step S3 also includes adding the color-protecting agent, keeping the water boiling, and blanching for 2 to 3 minutes; during this time, gently stirring to ensure the edamame are heated evenly.

4. The method for color protection processing of edamame for convenient dishes according to claim 1, characterized in that: In step S4.1, the effective chlorine concentration of the slightly acidic electrolyzed water in the slightly acidic electrolyzed water tank is controlled between 20 ppm and 30 ppm.

5. The method for color protection processing of edamame for convenient dishes according to claim 1, characterized in that: In step S4.1, the blanched edamame are soaked in a slightly acidic electrolytic water bath for 3 to 5 minutes.

6. The method for color protection processing of edamame for convenient dishes according to claim 1, characterized in that: The ice-water mixture described in step S4.2 is made by mixing ice blocks made from reverse osmosis water and reverse osmosis water in a mass ratio of 1:1 in a cooling tank, with the temperature kept constant at 0°C.

7. The method for color protection processing of edamame for convenient dishes according to claim 1, characterized in that: Step S5 also includes first draining the cooled edamame and then mixing it with the seasoning sauce; the seasoning sauce can be brine, brine or fermented brine.

8. The method for color protection processing of edamame for convenient dishes according to claim 7, characterized in that: The sauce in step S5 needs to be frozen in a cold storage at -18°C or below until a few ice crystals or ice cubes appear in the sauce.

9. The method for color protection processing of edamame for convenient dishes according to claim 1, characterized in that: It also includes step S6, packaging: The seasoned edamame and sauce are packaged together; the packaging material is a composite film bag or box that meets food hygiene standards.

10. A method for color-protecting processing of edamame for convenient dishes according to claim 9, characterized in that: Also includes step S7, commercially available: The packaged products are stored in a low-temperature cold storage at 0℃ to 4℃, and are transported and sold under these low-temperature conditions via cold chain.

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