Color protection composition and color protection method for preparing quick-frozen dandelion dish

Abstract

The invention relates to the field of food processing color protection, in particular to a color protection composition and a color protection method for preparing quick-frozen dandelion dishes, the composition comprises sodium ascorbate, calcium lactate and EDTA-2Na, dandelions are washed, then placed in blanching liquid containing the color protection composition to be blanched, quickly fished out after blanching is finished, and subjected to shock cooling with ice water to 10 DEG C or below, and a finished product is obtained. Draining off water, immediately quickly freezing, and freezing and preserving in a refrigerator at the temperature of-18 DEG C; according to the compound color protection formula provided by the invention, the safety risk of heavy metals is avoided, enzymatic browning can be inhibited, and the color of dandelion is stable; the blanching temperature and time parameters matched with the characteristics of the dandelion leaves are optimized, the problems of high-temperature long-time softening and rotting and low-temperature short-time enzyme inactivation are solved, and chlorophyll degradation and nutrition loss are reduced while the activities of polyphenol oxidase and peroxidase are ensured to be rapidly passivated; the synergistic effect of composite color protection and blanching processes is achieved, the process is simplified, and the method is suitable for large-scale production of quick-frozen vegetables.

Description

Technical Field

[0001] This invention relates to the field of color protection in food processing, and in particular to a color-protecting composition and method for preparing quick-frozen dandelion vegetables. Background Technology

[0002] Dandelion, a plant used both as food and medicine, is rich in polyphenols, chlorophyll, vitamins, and minerals, possessing both edible and medicinal value. Its demand in the frozen vegetable market has been steadily increasing in recent years. Quick-freezing technology can rapidly lock in the freshness of ingredients, extend shelf life, and retain nutrients to the greatest extent, making it the mainstream method for large-scale processing of wild vegetables. However, dandelion leaves are delicate and have fragile cell structures, making them highly susceptible to color deterioration during the entire process of sorting, washing, blanching, and freezing. This deterioration manifests as fading of green, yellowing, and even browning, severely reducing the product's commercial value and market acceptance, becoming a core technological bottleneck restricting the industrialization of frozen dandelion vegetables. From a market perspective, color is a core sensory indicator for frozen vegetables; color deterioration directly leads to a significant reduction in product value, severely hindering the market promotion of frozen dandelion vegetables. From an industry perspective, the industry urgently needs an integrated color-protection process that balances color stability, nutrient retention, and food safety to promote the large-scale, standardized production of frozen dandelion vegetables and fill the technological gap in this field.

[0003] Blanching is crucial for color preservation, but precise parameter matching is lacking: the core function of blanching is to deactivate oxidases such as PPO and POD, while inhibiting chlorophyll degradation. Temperature and time parameters directly affect the color preservation effect and nutrient retention. In existing patents, such as the invention patent CN109169856A entitled "Processing Technology for Quick-Frozen Winter Melon," for quick-freezing winter melon, the washing process uses a 0.1%-0.5% (preferably 0.3%) KMnO4 solution. The blanching process involves heating in boiling water at 80-100℃ for 10-20 minutes, followed by color preservation treatment at 15℃. After cooling to below 5℃, the melon undergoes secondary sorting and degassing, and is then frozen at -10℃ for 5 minutes. The core solution addresses the preservation and basic color protection issues in quick-frozen winter melon, improving product safety. However, it relies on low-temperature (15℃) color protection, lacks a composite color protection system, and the use of KMnO4 for cleaning poses a risk of residue buildup. It also struggles to address browning caused by dandelion chlorophyll degradation and polyphenol oxidation. In contrast, patent CN108077399A, titled "A Processing Technology for Quick-Frozen Red Chili Peppers," describes a method for quick-frozen red chili peppers involving soaking in a salt solution (salt:alum:water = 100:3:0.2) for color protection, followed by sterilization with a 200ppm chlorine solution, blanching at 97-100℃ for 60-90 minutes, and then cooling at -25℃ for 15 minutes. Quick-freezing within 1 minute, with an ice film on the surface, requires no preservatives and retains nutrients; In the invention patent with publication number CN108029747A, entitled "A Processing Technology for Quick-Frozen Carrots", for quick-freezing carrots, the same brine (salt: alum: water = 100:3:0.2) as red peppers is used for color protection, blanching at 98℃ or above for 50-55 seconds, followed by shaking to drain, pre-cooling, and quick-freezing within 15 minutes below -25℃, and storage at -18℃, solving the problems of carrot preservation and transportation; however, the use of salt and alum for color protection, alum contains aluminum, which poses a food safety risk; and the color-protecting components cannot stabilize the chlorophyll in dandelion leaves; In the invention patent with publication number CN117770386A, entitled "A Pretreatment Method for Quick-Frozen Broad Beans Combined with Color Protection and Green Preservation", for quick-frozen broad beans, blanching at 100±2℃ for 1.5-4.5 minutes. These parameters are designed for the enzyme activity characteristics of different vegetables. Dandelion's PPO activity peak and heat resistance differ from those of the aforementioned vegetables. Directly applying these parameters can lead to over-blanching and loss of green color or under-blanching and browning. At the same time, existing technologies have not formed a synergistic optimization scheme between the compound color-protecting agent formula and the blanching parameters, making it difficult to balance color stability and food texture. For example, the invention patent with publication number CN112088933A, entitled "A Processing Technology for Quick-Frozen Corn," uses 80℃ blanching for quick-frozen corn, but it requires blanching first and then soaking in low-temperature water for color protection. The process is cumbersome and has not been optimized for the enzyme activity of dandelion leaves, which can easily lead to under-blanching with unactivated enzymes or over-blanching and loss of green color.

[0004] Therefore, developing a composite color-protecting agent formula adapted to the specific characteristics of dandelion and combining it with blanching process parameters is key to breaking through the bottleneck in the processing of quick-frozen dandelion vegetables, and has significant technological innovation value and industrial application significance. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a color-protecting composition and method for preparing quick-frozen dandelion vegetables. It provides a composite color-protecting agent formulation with sodium ascorbate, calcium lactate, and EDTA-2Na as its core components. This formulation avoids the safety risks associated with heavy metals in existing technologies and inhibits enzymatic browning, achieving stable dandelion color. The invention optimizes the blanching temperature and time parameters to suit the characteristics of dandelion leaves, solving the problems of high-temperature, long-time blanching leading to softening and short-time low-temperature enzyme inactivation in existing technologies. This ensures rapid inactivation of polyphenol oxidase and peroxidase activity while reducing chlorophyll degradation and nutrient loss. The invention integrates the composite color-protecting agent with the blanching process, simplifying the procedure and adapting it to large-scale production of quick-frozen vegetables. This results in quick-frozen dandelion vegetables with bright color, crisp texture, and high nutrient retention, filling a gap in the field of color protection for quick-frozen dandelion.

[0006] To achieve the above objectives, the present invention is implemented according to the following technical solution: In one aspect, the present invention provides a color-protecting composition for preparing quick-frozen dandelion vegetables, the composition comprising sodium ascorbate, calcium lactate and EDTA-2Na.

[0007] The synergistic color-protecting effect of compound color-protecting agents has been proven in the food processing field, significantly improving the color stability of quick-frozen vegetables. However, a specific compound color-protecting agent formulation for dandelion, which is characterized by high polyphenol content, high enzyme activity, and strong heat sensitivity, has not yet been developed. The color-protecting composition provided by this invention is a compound color-protecting formulation with sodium ascorbate, calcium lactate, and EDTA-2Na as its core components. Sodium ascorbate provides antioxidant protection, calcium lactate enhances leaf texture, and EDTA-2Na chelates metal ions. Through the synergistic combination of these three components, it effectively resists oxidation, inhibits chlorophyll degradation, enhances leaf cell wall toughness, and prevents softening after quick-freezing. It precisely addresses the core pain points of dandelion quick-frozen vegetables, such as easy loss of chlorophyll and easy softening of leaves, achieving the dual effects of stable color and crisp texture.

[0008] In a preferred embodiment, the volume fractions of each component are: sodium ascorbate 2-4 parts; calcium lactate 0.5-2 parts; EDTA-2Na 0.5-2 parts.

[0009] In a preferred embodiment, the volume fraction of each component is: 3 parts sodium ascorbate; 1 part calcium lactate; and 1 part EDTA-2Na.

[0010] Another aspect of the present invention provides a method for color protection in preparing quick-frozen dandelion vegetables. After washing the dandelion, it is blanched in a blanching solution containing the color-protecting composition according to any one of claims 1-3. After blanching, the dandelion is quickly removed and rapidly cooled to below 10°C with ice water. After draining the water, the treated dandelion is immediately quick-frozen and then stored in a freezer at -18°C.

[0011] This product utilizes a composite color-protecting agent and a suitable blanching process, specifically designed for quick-frozen dandelion vegetables. On one hand, the integrated process is compatible with the continuous production of quick-freezing production lines, eliminating the need for additional low-temperature soaking steps. On the other hand, sodium ascorbate reduces vitamin oxidation and loss, while calcium lactate protects both color and texture. The blanching process controls nutrient loss and inactivates enzymes to inhibit browning, ultimately resulting in quick-frozen dandelion vegetables with bright color, crisp texture, and minimal nutrient loss. This fills the gap in existing technologies for quick-freezing color protection processes specifically for dandelion.

[0012] In a preferred embodiment, the bleaching liquid is a solvent water to which the color-protecting composition is added, and the amount of the color-protecting composition added is 0.5 to 1.7 g / L.

[0013] In a preferred embodiment, the rinsing temperature is 90–100°C, and the rinsing time is 60–120 seconds.

[0014] Blanching temperature and time are key process parameters affecting enzyme inactivation efficiency and chlorophyll retention rate. They need to be precisely optimized in light of the delicate and fragile cellular characteristics of dandelion leaves to address the technical pain point of mismatch between process parameters and dandelion characteristics in existing technologies. The blanching temperature and time parameters of this invention are designed based on the enzyme activity of dandelion leaves and their characteristics such as thin leaves, poor temperature resistance, and high polyphenol content. This allows for high-temperature, short-time blanching, which can thoroughly inactivate polyphenol oxidase and peroxidase in dandelion while reducing chlorophyll degradation and leaf softening, thus balancing enzyme inactivation and quality preservation. At the same time, it is combined with a compound color-protecting agent to achieve integrated blanching and color protection, solving the problems of mismatched parameters and cumbersome processes in existing technologies.

[0015] In a preferred embodiment, the cleaning process involves soaking the dandelion in a 0.3-1% NaCl solution for 5-20 minutes, followed by rinsing with clean water at least twice to remove impurities and control the growth of microorganisms.

[0016] Compared with the prior art, the present invention has the following beneficial effects: Taking advantage of the fact that dandelion is rich in flavonoids, polyphenols and chlorophyll, the color-protecting composition of this invention uses only sodium ascorbate (an antioxidant permitted by GB 2760), calcium lactate (a food-grade calcium fortifier that improves texture while ensuring safety), and EDTA-2Na (a food-grade metal ion chelating agent). All three are commonly used safe additives in the food industry and are free of harmful components such as aluminum and heavy metals. While ensuring the color-protecting effect, it meets the food safety requirements of quick-frozen dandelion vegetables and solves the safety hazards of existing technologies. This color-protection method is adapted to the quick-freezing scenario of dandelion, meeting the color protection needs of the delicate and fragile dandelion leaves, while taking into account color, texture, and nutrition, filling the gap in color protection technology for quick-frozen dandelion vegetables. A synergistic control system for the color-protection composition and method is established, solving the problems of poor immediate color protection, continuous color deterioration during storage, and accelerated browning due to enzyme activity recovery after thawing through the synergistic effect of "chemical color protection + heat treatment," thus ensuring product color stability and commercial value. The technical feasibility of this invention has been verified through laboratory comparative experiments, and its large-scale application feasibility has been verified through actual factory production. The final quick-frozen dandelion vegetables produced meet the market's quality requirements for high-quality quick-frozen dandelion vegetables in terms of bright color, crisp texture, and production stability. The transformation and application of this invention will benefit the industrialization of quick-frozen dandelion vegetables. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the experimental design for the present invention; Figure 2 Color difference under different amounts of color-protecting composition, bleaching temperature, and bleaching time; Figure 3 Browning degree under different amounts of color-protecting composition, bleaching temperature, and bleaching time. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Example 1

[0020] Example 1 of the present invention provides a color-protecting composition for preparing quick-frozen dandelion vegetables. The composition comprises, by volume fraction, 3 parts sodium ascorbate, 1 part calcium lactate, and 1 part EDTA-2Na.

[0021] A method for color protection in the preparation of quick-frozen dandelion vegetables includes the following processing steps: 1) Select fresh dandelion as raw material, remove the roots of the dandelion, soak it in 0.5% NaCl solution for 10 minutes, and rinse it with clean water 3 times; 2) Add the color-protecting composition to water to form a bleaching solution, wherein the amount of color-protecting composition added is 1.5 g / L; heat the bleaching solution to 95℃; 3) Place the dandelion treated in step 1) into the blanching solution and blanch for 90 seconds. After blanching, quickly remove the dandelion and cool it with ice water to below 10°C, then drain the water. 4) Immediately place the dandelions treated in step 3) into a -35℃ freezer for quick freezing, and then store them in a -18℃ freezer. Example 2

[0022] Example 2 of the present invention provides a color-protecting composition for preparing quick-frozen dandelion vegetables. The composition comprises, by volume fraction, 2 parts sodium ascorbate, 0.5 parts calcium lactate, and 0.5 parts EDTA-2Na.

[0023] A method for color protection in the preparation of quick-frozen dandelion vegetables includes the following processing steps: 1) Select fresh dandelion as raw material, remove the roots of the dandelion, soak it in 1% NaCl solution for 5 minutes, and rinse it with clean water 3 times; 2) Add the color-protecting composition to water to form a bleaching solution, wherein the amount of color-protecting composition added is 1.7 g / L; heat the bleaching solution to 90℃; 3) Place the dandelion treated in step 1) into the blanching solution and blanch for 120 seconds. After blanching, quickly remove the dandelion and cool it with ice water to below 10°C, then drain the water. 4) Immediately place the dandelions treated in step 3) into a -35℃ freezer for quick freezing, and then store them in a -18℃ freezer. Example 3

[0024] Example 3 of the present invention provides a color-protecting composition for preparing quick-frozen dandelion vegetables. The composition comprises, by volume fraction, 4 parts sodium ascorbate, 2 parts calcium lactate, and 2 parts EDTA-2Na.

[0025] A method for color protection in the preparation of quick-frozen dandelion vegetables includes the following processing steps: 1) Select fresh dandelion as raw material, remove the roots of the dandelion, soak it in 0.3% NaCl solution for 20 minutes, and rinse it with clean water 3 times; 2) Add the color-protecting composition to water to form a bleaching solution, wherein the amount of color-protecting composition added is 0.5 g / L; heat the bleaching solution to 100℃; 3) Place the dandelion treated in step 1) into the blanching solution and blanch for 60 seconds. After blanching, quickly remove the dandelion and cool it with ice water to below 10°C, then drain the water. 4) Immediately place the dandelions treated in step 3) into a -35℃ freezer for quick freezing, and then store them in a -18℃ freezer. Example 4

[0026] Example 4 of the present invention provides a color-protecting composition for preparing quick-frozen dandelion vegetables. The composition comprises, by volume fraction, 3 parts sodium ascorbate, 1.5 parts calcium lactate, and 0.5 parts EDTA-2Na.

[0027] A method for color protection in the preparation of quick-frozen dandelion vegetables includes the following processing steps: 1) Select fresh dandelion as raw material, remove the roots of the dandelion, soak it in 0.8% NaCl solution for 7 minutes, and rinse it 3 times with clean water; 2) Add the color-protecting composition to water to form a bleaching solution, wherein the amount of color-protecting composition added is 1 g / L; heat the bleaching solution to 97°C; 3) Place the dandelion treated in step 1) into the blanching solution and blanch for 70 seconds. After blanching, quickly remove the dandelion and cool it with ice water to below 10°C, then drain the water. 4) Immediately place the dandelions treated in step 3) into a -35℃ freezer for quick freezing, and then store them in a -18℃ freezer. Example 5

[0028] Example 5 of the present invention provides a color-protecting composition for preparing quick-frozen dandelion vegetables. The composition comprises, by volume fraction, 4 parts sodium ascorbate, 1 part calcium lactate, and 1.5 parts EDTA-2Na.

[0029] A method for color protection in the preparation of quick-frozen dandelion vegetables includes the following processing steps: 1) Select fresh dandelion as raw material, remove the roots of the dandelion, soak it in 0.4% NaCl solution for 15 minutes, and rinse it with clean water 3 times; 2) Add the color-protecting composition to water to form a bleaching solution, wherein the amount of color-protecting composition added is 1.3 g / L; heat the bleaching solution to 93°C; 3) Place the dandelion treated in step 1) into the blanching solution and blanch for 110 seconds. After blanching, quickly remove the dandelion and cool it with ice water to below 10°C, then drain the water. 4) Immediately place the dandelions treated in step 3) into a -35℃ freezer for quick freezing, and then store them in a -18℃ freezer.

[0030] Experimental Example Experimental Methods: Fresh dandelion was selected as the raw material. The roots of the dandelion were removed, and the dandelion was soaked in 0.5% NaCl solution for 10 minutes and rinsed three times with clean water. The color-protecting composition of Example 1 was added to water to form a bleaching solution. The bleaching solution was heated, and the dandelion was placed in the bleaching solution for bleaching. After bleaching, the dandelion was quickly removed and rapidly cooled to below 10°C with ice water. The water was drained, and the treated dandelion was immediately placed in a -35°C freezer for quick freezing. Then it was stored in a -18°C freezer. After 7 days, the samples were thawed and the indicators were measured. Three samples were prepared for each treatment, and the color difference and browning index were measured respectively.

[0031] The first group of experiments: The amount of color-protecting composition added was 0 g / L, 0.5 g / L, 1 g / L, 1.5 g / L and 2 g / L, respectively. The blanching temperature was set at 95℃ and the blanching time was 90 s. The effects of different addition amounts on the indicators were observed.

[0032] The second group of experiments: The amount of color-protecting composition added was 1.5 g / L, the blanching time was set to 90 s, and the blanching temperatures were 80℃, 85℃, 90℃, 95℃ and 100℃, respectively, to observe the effect of different blanching temperatures on the indicators.

[0033] The third group of experiments: The amount of color-protecting composition added was 1.5 g / L, the bleaching temperature was set at 95℃, and the bleaching times were 30 s, 60 s, 90 s, 120 s, and 150 s, respectively. The effects of different bleaching times on the indicators were observed.

[0034] The experimental design process is as follows: Figure 1 As shown.

[0035] Color difference detection method: Use a colorimeter to measure the color difference, and after correction using a white board, determine the L, a, and b values ​​of dandelion.

[0036] Browning degree detection method: Take 0.5g of dandelion, add 10 mL of deionized water, grind into a homogenate, centrifuge at 12000 r / min for 10 min, take the supernatant, and measure the absorbance at a wavelength of 420 nm. The result is expressed as A420 for browning degree.

[0037] Experimental results: The effects of different amounts of color-protecting compositions, blanching temperature, and blanching time on the color difference of quick-frozen dandelion vegetables are as follows: Figure 2 -a~ Figure 2 -f is shown.

[0038] Figure 2 -a、 Figure 2 -b represents the effect of the amount of color-protecting composition added on the color difference of dandelion quick-frozen vegetables (L). * a * The impact. L * Indicates brightness, a * The value represents the red-green value, with positive values ​​representing red and negative values ​​representing green. The results show that as the amount of color-protecting composition added increases, L... * It shows a trend of first increasing and then decreasing, a * The value first decreases and then increases; when the amount of color-protecting composition added is 1.5 g / L, L * Reaching the highest, a * The lowest concentration was observed, indicating that this addition significantly improves the brightness and green color retention of frozen dandelion vegetables. A significant difference was observed between the 1.5 g / L concentration and other groups. P The concentration of the color-protecting composition is less than 0.05, indicating that the amount added has a significant effect on the color.

[0039] Figure 2 -c、 Figure 2 -d represents the effect of blanching temperature on the color difference of frozen dandelion vegetables (L). * a * The impact. L * The temperature rises with increasing blanching temperature, reaching its peak at 95℃ and decreasing at 100℃; a * The color retention gradually decreased with increasing temperature, rebounding at 100℃. This indicates that the inhibition of enzyme activity was strengthened during the heating process, maintaining the brightness and green color of the frozen dandelion vegetables; however, excessively high temperatures could damage chlorophyll and other structures, reducing the color-protecting effect. A significant difference was observed between 95℃ and other groups. P The value <0.05 indicates that the bleaching temperature has a significant effect on the color.

[0040] Figure 2 -e、 Figure 2 -f shows the effect of blanching time on the color difference of frozen dandelion vegetables. * a * The function of L. * The temperature rises with increasing blanching time, reaching its peak at 90 seconds, and then decreases; a * The value gradually decreased over time, reaching its lowest point at 90 seconds, and then rebounded. This indicates that prolonged blanching time can effectively inactivate enzymes, improving brightness and greenness; however, excessive blanching time can damage cell structure due to overheating, causing contents to leak out and weakening the color-protecting effect. A significant difference was observed between 90 seconds and other groups. P The value <0.05 indicates that the blanching time has a significant effect on the color.

[0041] The effects of different amounts of color-protecting compositions, blanching temperatures, and blanching times on the browning degree of quick-frozen dandelion vegetables are as follows: Figure 3 -a~ Figure 3 -c is shown.

[0042] Figure 3 -a represents the effect of the amount of color-protecting composition added on the browning degree of quick-frozen dandelion vegetables. Browning degree reflects the degree of color deterioration of the sample; the lower the value, the better the color-protecting effect. The results showed that with the increase of the amount of color-protecting composition added, the browning degree first decreased and then increased; when the amount of color-protecting composition added was 1.5 g / L, the browning degree reached the lowest level, indicating that this amount can significantly inhibit the browning of quick-frozen dandelion vegetables. There were significant differences between groups ( P <0.05%, verifying that the amount of color-protecting composition added significantly affects browning degree; an appropriate amount of color-protecting composition can effectively delay browning, while excessive amounts may weaken the color-protecting effect. A significant difference was found between 1.5 g / L and other groups. P The value is <0.05, indicating that the amount of color-protecting composition added has a significant effect on the degree of browning.

[0043] Figure 3 -b represents the effect of blanching temperature on the browning degree of quick-frozen dandelion vegetables. The results showed that the browning degree decreased with increasing blanching temperature, reaching its lowest point at 95℃, and increasing further at 100℃. This indicates that during the heating process, enzyme activity was increasingly inhibited, which was beneficial for reducing browning degree. 95℃ was the optimal blanching temperature, significantly inhibiting browning in quick-frozen dandelion vegetables. At 100℃, the high temperature damaged cell structure, exposing the browning substrate and leading to an increase in browning degree, indicating that blanching temperature had a significant effect on browning degree. There was a significant difference between 95℃ and other groups (…). P The value <0.05 indicates that the blanching temperature has a significant effect on the degree of browning.

[0044] Figure 3 -c represents the effect of blanching time on the browning degree of quick-frozen dandelion vegetables. The results show that the browning degree decreases with increasing blanching time, reaching its lowest point at 90 s, after which it increases. This indicates that extending the blanching time can more effectively inactivate enzymes and reduce browning. 90 s is the optimal blanching time, significantly inhibiting browning. After 120 s, excessive heat treatment damages the stability of color-related substances, leading to an increase in browning degree, demonstrating the significant effect of blanching time on browning.

[0045] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the color-protecting composition comprises, by volume fraction, 3 parts sodium ascorbate, 3 parts calcium lactate, and 3 parts EDTA-2Na.

[0046] Based on the analysis in Table 1, in Comparative Example 1, excessive calcium lactate led to excessive hardening of the tissue, a dry texture, and competitive consumption of EDTA-2Na, inducing browning; excessive EDTA-2Na caused complexation of dandelion minerals, reducing nutritional value, and giving the product a metallic taste; the color-protecting effect decreased, the texture became soft and inelastic, the flavor was abnormal, and a large amount of nutrients were lost.

[0047] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the color-protecting composition comprises, by volume fraction, 1 part sodium ascorbate, 3 parts calcium lactate, and 0.2 parts EDTA-2Na.

[0048] Based on the analysis in Table 1, in Comparative Example 2, the sodium ascorbate level was too low: insufficient PPO inhibition, accelerated browning, and loss of chlorophyll and functional components; excessive calcium lactate led to excessive tissue hardening, a dry texture, and competitive consumption of EDTA-2Na, inducing browning; insufficient EDTA-2Na resulted in the inability to effectively chelate metal ions at the active center of PPO, leading to uncontrolled enzymatic browning and accelerated chlorophyll degradation; the color-protecting effect decreased, the texture became soft and inelastic, the flavor was abnormal, and a large amount of nutrients were lost.

[0049]

[0050] Experimental results show that Example 1 has a significantly better overall effect in terms of color protection and crispness retention than the comparative example. Data shows that Example 1 has the highest brightness, best greenness retention, moderate hardness, and no aging phenomenon. In contrast, the a-values ​​of Comparative Example 1 and Comparative Example 2 are only around -14, and the texture is significantly harder due to the excessively high calcium lactate content. This confirms that simply increasing the concentration of the color-protecting agent or decreasing its dosage cannot achieve the desired effect. Only the specific ratio of 3 parts sodium ascorbate, 1 part calcium lactate, and 1 part EDTA-2Na in Example 1 achieves the best synergy between the components, effectively solving the browning and softening problems of quick-frozen dandelions.

[0051] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A color-protecting composition for preparing a dandelion quick-frozen vegetable, characterized by comprising, The composition comprises sodium ascorbate, calcium lactate and EDTA-2Na.

2. A colour care composition for preparing a dandelion quick-frozen vegetable according to claim 1, characterized in that, The volume fraction of each component is: 2-4 parts of sodium ascorbate; 0.5-2 parts of calcium lactate; and 0.5-2 parts of EDTA-2Na.

3. A color protection composition for preparing dandelion quick-frozen vegetable according to claim 2, characterized in that, The volume fraction of each component is: 3 parts of sodium ascorbate; 1 part of calcium lactate; and 1 part of EDTA-2Na.

4. A method for preparing a color-protected frozen dandelion vegetable, characterized by, After the dandelions are washed, they are blanched in a blanching solution containing the color protection composition according to any one of claims 1-3, and then quickly taken out after the blanching is completed, and rapidly cooled to below 10℃ with ice water, drained, and immediately quick-frozen, and then stored in a refrigerator at -18℃.

5. The method for preparing the dandelion quick-frozen vegetable according to claim 4, characterized in that, The blanching solution is solvent water to which the color protection composition is added, and the color protection composition is added in an amount of 0.5-1.7 g / L.

6. The method for preparing the color-protected frozen dandelion vegetable according to claim 4, wherein, The blanching temperature is 90-100℃, and the blanching time is 60-120 s.

7. The method for preparing the dandelion quick-frozen vegetable according to claim 4, characterized in that, The washing is performed by immersing the dandelions in a 0.3-1% NaCl solution for 5-20 min, and then rinsing with water at least twice.

8. A method of preparing a dandelion quick-frozen vegetable, characterized by, The color protection method according to claim 4 is used for color protection.

9. A dandelion quick-frozen vegetable, characterized by, Prepared by the preparation method according to claim 8.

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