Processing method for freezing and freshness locking of mussels

Abstract

The invention belongs to the technical field of aquatic product preservation, and relates to a processing method for freezing and freshness locking of mussels. The invention aims to realize comprehensive improvement of the frozen fresh-keeping quality of the mussels through collaborative innovation of a quality improving and fresh-keeping technology and a liquid freezing process. The core thought of the method is as follows: on the premise that raw materials are finely cleaned and temporarily cultured and purified, a quality improvement solution is firstly adopted for fresh locking treatment, and then a liquid quick-freezing technology is combined to realize efficient freezing and fresh locking, so that the bottlenecks of a traditional freezing mode in the aspects of texture, flavor and safety performance are broken through, and the quality requirements of a high-end market on fresh-grade frozen mussels are met.

Description

Technical Field

[0001] This invention belongs to the field of aquatic product preservation technology and relates to a processing method for freezing and locking in the freshness of mussels. Background Technology

[0002] Mussels, a well-known bivalve mollusc, are a major aquaculture species globally due to their wide distribution and adaptability. In my country, the main farmed species include the purple mussel, the green mussel, and the thick-shelled mussel. These mussels are not only delicious but also rich in protein, essential amino acids, vitamins, and minerals, making them popular with consumers. Common mussel products on the market include fresh mussels, frozen mussels, and dried mussels. Given the perishable nature of mussels, the need for freezing and preservation technology is particularly urgent.

[0003] However, traditional air-freezing technologies (including spiral and tunnel freezing) have many shortcomings, greatly limiting the improvement of mussel product quality and market expansion. First, traditional freezing technologies have a slow freezing speed. For example, gas freezing (at -18°C) requires several hours to freeze mussel meat. During this process, the ice crystals formed are large (diameter > 100μm), damaging the cell structure of the mussel meat, leading to fiber breakage and severe juice loss; the thawing water loss rate can even reach over 20%. Second, during slow freezing, lipid oxidation intensifies, and water-soluble components such as taurine seep out with the juice, causing not only flavor degradation but also a significant reduction in nutritional value. Furthermore, products obtained using existing freezing technologies have a loose texture and a strong fishy smell, making it difficult to meet the high-end market's requirements for "fresh-grade" quality.

[0004] To overcome these challenges, optimization and upgrades to freezing technology and processing procedures are needed. Liquid nitrogen quick-freezing technology achieves ultra-low temperature quick-freezing by directly spraying -196℃ liquid nitrogen, controlling ice crystal diameter to within 30μm and significantly reducing thawing water loss (optimally below 3%). However, this liquid nitrogen freezing is very expensive, requiring approximately 1.5 kg of liquid nitrogen per kilogram of mussel meat, costing 3-5 times more than traditional freezing methods. Furthermore, its stringent equipment requirements limit its large-scale application. High-pressure freezing (HPP) technology inhibits ice crystal growth by applying pressure of 200-400 MPa, but its high equipment investment and maintenance costs, as well as the resulting firm texture, pose challenges for practical application. While ultrasonic-assisted salt freezing pretreatment technology is less expensive and effectively accelerates salt penetration, shortening processing time to less than one hour, it still requires conventional cold storage freezing afterward, failing to address the negative impacts of ice crystal formation, resulting in a still relatively high thawing water loss rate (15%-20%).

[0005] While these new technologies offer the possibility of improving the quality of frozen mussels, their respective shortcomings cannot be ignored. This indicates that current technological advancements require further exploration and optimization to find more efficient, economical, and environmentally friendly freezing and preservation methods, thereby further enhancing the quality and market competitiveness of mussel products. This not only represents an innovation in traditional food processing technology but also brings new development opportunities to the mussel industry. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a method for freezing and preserving the freshness of mussels, which shortens the freezing time to within 15 minutes, controls the thawing water loss rate to within 10%, and significantly improves the freshness of frozen mussel products.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A method for processing frozen mussels, the method comprising the following steps:

[0009] S1. The mussels are cleaned of impurities and temporarily purified in raw water.

[0010] S2. After the mussels have been temporarily held and purified, they are sorted a second time to remove dead individuals. The mussels after removing the dead individuals are then steamed and cooked to inactivate enzymes, and then the mussel meat is removed.

[0011] S3. Rinse the mussel meat in salt water and then soak it in the quality improvement solution;

[0012] S4. Then seal the mussel meat in plastic and flash freeze it.

[0013] S5. Finally, refrigerate the frozen mussel meat.

[0014] As a preferred option, the impurity removal process in step S1 includes: 1) cleaning the mussels with a brush roller machine, with a single cleaning time of 5-10 minutes; 2) sorting, i.e., removing damaged and dead mussels.

[0015] In the above-mentioned processing method for freezing and preserving freshness of mussels, step S1, the raw water temporary holding and purification treatment, uses seawater from the mussel's place of origin to temporarily hold the mussels for 12-36 hours at a water temperature of 10-18℃.

[0016] As a preferred method, the raw water temporary holding and purification treatment uses seawater from the mussel's native habitat (i.e., seawater from the same sea area as the mussel's production region). This seawater is filtered and purified, and then used to temporarily hold the mussels for 12-36 hours through a circulating water system at a water temperature of 10-18℃. This raw water temporary holding and purification treatment allows the mussels to expel sand in a favorable holding environment, thereby improving the cleanliness and taste of the mussel meat.

[0017] In the above-mentioned processing method for freezing and preserving freshness of mussels, the enzyme inactivation treatment in step S2 is carried out at a temperature of 80-100℃ for 1-3 minutes.

[0018] As a preferred method, the process of separating the mussel meat specifically involves processing the steamed mussels to extract the meat. First, the two shells are tightly clamped together to hold the byssal threads, and the byssal threads are quickly pulled off. Then, the adductor connecting the mussel meat to the two shells is cut off with a mussel knife, and the two shells are removed to obtain pure mussel meat.

[0019] In the above-mentioned method for freezing and preserving freshness of mussels, the brine concentration in step S3 is 1-3 wt%.

[0020] In the above-mentioned method for freezing and preserving the freshness of mussels, the soaking temperature in step S3 is 5-10℃, and the time is 2-4 hours. Maintaining a temperature of 5-10℃ in this invention helps to preserve the quality of the mussel meat and also prepares it for rapid freezing.

[0021] In the above-mentioned method for freezing and preserving the freshness of mussels, the quality improvement solution in step S3 includes the following raw materials in parts by weight: 0.6-0.7 parts sodium bicarbonate, 0.3-0.5 parts sodium citrate, 0.1-0.3 parts sodium chloride, and 98.5-99 parts water. The specific formula ratio can be dynamically adjusted according to the season and production area. For example, mussels from high-salinity sea areas have lower water content, so the proportion of sodium bicarbonate can be increased to improve water retention. This invention uses a freshness-preserving formula composed of sodium bicarbonate, sodium citrate, and edible salt for quality improvement. Sodium bicarbonate can increase the pH value through weak alkalinity, thereby increasing the repulsive force between protein molecules and loosening the protein network structure, thus improving water retention. Sodium citrate can bind heavy metal ions (such as copper and zinc), preventing them from catalyzing the formation of off-flavors, and at the same time, it protects the pigment structure and maintains the color of aquatic products through chelation. Salt can improve water retention, remove fishy odors and microorganisms from the surface of shellfish, and activate umami receptors to enhance the natural flavor of seafood (e.g., the umami perception of glutamic acid requires sodium). + participate).

[0022] In the above-mentioned method for freezing and preserving the freshness of mussels, step S4, sealing, specifically includes: after packaging the mussel meat into bags, adding water at 10%-20% of the mussel meat's weight, and then vacuuming to 80-95% vacuum. The ice layer formed after the water freezes can block oxygen contact, delay fat oxidation and protein denaturation, maintain the original flavor, prevent muscle fibers from dehydrating and hardening, and keep the mussel meat tender and juicy.

[0023] In the above-mentioned method for freezing and preserving the freshness of mussels, step S4, rapid freezing, utilizes an ultra-low temperature rapid freezing device containing a freezing liquid with a freezing point ≤50℃. The freezing liquid comprises the following raw materials in parts by weight: 40-50 parts sodium chloride, 10-15 parts calcium chloride, and 50-100 parts water. The main components of the freezing liquid are edible salt and calcium chloride, both food-grade materials, which, when combined, form an ultra-low temperature solution.

[0024] In the above-mentioned method for freezing and preserving freshness of mussels, the temperature of the freezing liquid is ≤-35℃, the rapid freezing time is 10-20min, and the rapid freezing rate is ≥5℃ / min.

[0025] In the above-mentioned processing method for freezing and preserving freshness of mussels, the average particle size of ice crystals in the mussel meat after rapid freezing in step S4 is <50μm.

[0026] In the above-mentioned processing method for freezing and preserving freshness of mussels, the refrigeration temperature in step S5 is -(10-25)℃.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention aims to comprehensively improve the quality of frozen mussels through the synergistic innovation of quality improvement and freshness-locking technology and liquid freezing process. The core idea is: after the raw materials have undergone meticulous cleaning and temporary purification, a quality improvement solution is first used for freshness-locking treatment, followed by liquid quick-freezing technology to achieve efficient freezing and freshness-locking. This breaks through the bottlenecks of traditional freezing methods in terms of texture, flavor, and safety, meeting the high-end market's demand for "fresh-grade" frozen mussels.

[0029] 2. Regarding water retention and improved eating experience, this invention employs a compound freshness-locking formula with sodium carbonate, sodium citrate, and edible salt as the main components. This formula effectively regulates the water activity (Aw) of mussel meat, significantly reducing the migration and crystallization of free water during freezing, thereby minimizing the damage to cell structure caused by ice crystal formation. After this treatment, the elasticity recovery rate of mussel meat upon thawing can be increased to over 90%, achieving a taste quality close to that of fresh mussels, greatly enhancing the product's eating experience.

[0030] 3. Regarding rapid freezing and freshness preservation, this invention introduces liquid quick-freezing technology, using ultra-low temperature liquid at -35℃ or below as the cooling medium. Due to the high thermal conductivity of liquids, rapid and uniform heat transfer is achieved, allowing mussels to complete the freezing process within 15 minutes, with a freezing rate of ≥5℃ / min. This speed is far higher than traditional cold storage freezing (usually requiring 4-6 hours) and spiral / tunnel quick-freezing (usually requiring more than 1 hour), significantly reducing the formation of large ice crystals. It effectively prevents cell membrane rupture and juice loss at the microscopic level, resulting in a water loss rate of less than 10% after thawing. Boiling tests demonstrate a significant improvement in the overall quality of the processed product, preserving the original freshness and nutritional value of the mussels to the greatest extent possible.

[0031] 4. Regarding quality maintenance for long-term storage and transportation, this invention adds purified water to the vacuum-packed mussel meat before salt freezing. The ice layer can block oxygen contact, delay fat oxidation and protein denaturation, maintain the original flavor, and enhance the stability and safety of the product during transportation, storage and market circulation. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention patent clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this invention patent and are not intended to limit the scope of this invention patent.

[0033] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0034] The terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., used in this invention refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example. Furthermore, the technical features involved in the various embodiments of the invention can be combined with each other as long as they do not conflict with each other.

[0035] Unless otherwise specified, the raw materials and equipment used in this invention can be purchased from the market or are commonly used in the field. Unless otherwise specified, the methods in the embodiments are conventional methods in the field.

[0036] Example 1:

[0037] S1. Select mussels from the sea area of ​​Gouqi Township, Shengsi County, Zhoushan City, Zhejiang Province. Use a brush roller machine to clean them. Each cleaning session lasts 8 minutes. Manually inspect and sort the mussels, removing any damaged or dead ones. Select mussels with a shell length of about 8cm for temporary purification in raw water. The temporary purification temperature is 16℃ and the time is 18 hours.

[0038] S2. After temporary holding, the mussels are sorted a second time, and dead individuals with openings exceeding 0.5cm are removed. The mussels after removing the dead individuals are poured into an elevator and heated by a steamer at 85℃ for 2.5 minutes. After steaming, the mussels are processed to extract the meat. First, the two shells are tightly clamped together with the byssal threads, and the byssal threads are quickly pulled off. Then, the adduct connecting the mussel meat to the two shells is cut off with a mussel knife, and the two shells are removed to obtain pure meat mussels.

[0039] S3. Wash the shucked mussel meat with salt water. Drain the washed mussel meat until the water drips out in a continuous stream. The salt water concentration is 1 wt%. Mix the mussel meat with the quality improvement solution and soak for 2.5 hours, stirring constantly. The temperature is controlled at 8°C. The quality improvement solution is a freshness-locking formula solution made of sodium carbonate, sodium citrate, and edible salt, including the following parts by weight: 0.6 parts sodium bicarbonate, 0.4 parts sodium citrate, 0.2 parts sodium chloride, and 98.8 parts water.

[0040] S4. Pack the mussel meat into bags, add water equal to 20% of the meat's weight, then vacuum-seal the bags to 90% vacuum level. After vacuuming, seal the bags. Spread the packaged mussel meat flat on a conveyor belt for rapid freezing. Place the bagged mussel meat into a freezing liquid tank (freezing liquid temperature is -35℃) at a freezing rate of 5℃ / min. After freezing for 15 minutes, remove the mussel meat from the freezing liquid tank. The freezing liquid is an ultra-low temperature freezing point liquid prepared from calcium chloride, edible salt, and water. The freezing liquid includes the following raw materials in parts by weight: 45 parts sodium chloride, 12 parts calcium chloride, and 80 parts water.

[0041] S5. Store the flash-frozen products in a -18℃ freezer.

[0042] Example 2:

[0043] S1. Select mussels from the sea area of ​​Gouqi Township, Shengsi County, Zhoushan City, Zhejiang Province. Use a brush roller machine to clean them. Each cleaning session lasts 8 minutes. Manually inspect and sort the mussels, removing any damaged or dead ones. Select mussels with a shell length of about 8cm for temporary purification in raw water. The temporary purification temperature is 16℃ and the time is 18 hours.

[0044] S2. After temporary holding, the mussels are sorted a second time, and dead individuals with openings exceeding 0.5cm are removed. The mussel raw materials after removing the dead individuals are poured into the elevator and heated by the steamer at 80℃ for 1 minute. After steaming, the mussels are processed to extract the meat. First, the two shells are tightly clamped together with the byssal threads, and the byssal threads are quickly pulled off. Then, the adduct connecting the mussel meat to the two shells is cut with a mussel knife, and the two shells are removed to obtain pure meat mussels.

[0045] S3. Wash the shucked mussel meat with salt water. Drain the washed mussel meat until the water droplets no longer form a stream. The salt water concentration is 3wt%. Mix the mussel meat with the quality improvement solution evenly and soak for 2 hours, stirring constantly. The temperature is controlled at 5℃. The quality improvement solution is a freshness-locking formula solution composed of sodium carbonate, sodium citrate, and edible salt, including the following parts by weight of raw materials: 0.7 parts sodium bicarbonate, 0.5 parts sodium citrate, 0.3 parts sodium chloride, and 98.5 parts water.

[0046] S4. Pack the mussel meat into bags, add water equal to 10% of the meat's weight, then vacuum-seal the bags to 80% vacuum level. After vacuuming, seal the bags. Spread the packaged mussel meat flat on a conveyor belt for rapid freezing. Place the bags into a freezing liquid tank (freezing liquid temperature is -35℃) at a freezing rate of 5℃ / min. After freezing for 10 minutes, remove the mussel meat from the freezing liquid tank. The freezing liquid is an ultra-low temperature freezing point liquid prepared from calcium chloride, edible salt, and water. The freezing liquid includes the following raw materials in parts by weight: 40 parts sodium chloride, 10 parts calcium chloride, and 50 parts water.

[0047] S5. Store the flash-frozen products in a -18℃ freezer.

[0048] Example 3:

[0049] S1. Select mussels from the sea area of ​​Gouqi Township, Shengsi County, Zhoushan City, Zhejiang Province. Use a brush roller machine to clean them. Each cleaning session lasts 8 minutes. Manually inspect and sort the mussels, removing any damaged or dead ones. Select mussels with a shell length of about 8cm for temporary purification in raw water. The temporary purification temperature is 16℃ and the time is 18 hours.

[0050] S2. After temporary holding, the mussels are sorted a second time, and dead individuals with openings exceeding 0.5cm are removed. The mussels after removing the dead individuals are poured into an elevator and heated by a steamer at 100℃ for 1 minute. After steaming, the mussels are processed to extract the meat. First, the two shells are tightly clamped together with the byssal threads, and the byssal threads are quickly pulled off. Then, the adduct connecting the mussel meat to the two shells is cut off with a mussel knife, and the two shells are removed to obtain pure meat mussels.

[0051] S3. Wash the shucked mussel meat with salt water. Drain the washed mussel meat until the water drips out in a continuous stream. The salt water concentration is 2wt%. Mix the mussel meat with the quality improvement solution evenly and soak for 5 hours, stirring constantly. The temperature is controlled at 10℃. The quality improvement solution is a freshness-locking formula solution composed of sodium carbonate, sodium citrate, and edible salt, including the following parts by weight of raw materials: 0.6 parts sodium bicarbonate, 0.3 parts sodium citrate, 0.3 parts sodium chloride, and 98.8 parts water.

[0052] S4. Pack the mussel meat into bags, add water equal to 20% of the meat's weight, then vacuum-seal the bags to 95% vacuum level. After vacuuming, seal the bags. Spread the packaged mussel meat flat on a conveyor belt for rapid freezing. Place the bagged mussel meat into a freezing liquid tank (freezing liquid temperature is -35℃) at a freezing rate of 5℃ / min. After freezing for 20 minutes, remove the mussel meat from the freezing liquid tank. The freezing liquid is an ultra-low temperature freezing point liquid prepared from calcium chloride, edible salt, and water. The freezing liquid includes the following raw materials in parts by weight: 50 parts sodium chloride, 15 parts calcium chloride, and 100 parts water.

[0053] S5. Store the flash-frozen products in a -18℃ freezer.

[0054] Comparative Example 1:

[0055] The only difference from Example 1 is that the mussel meat is not soaked in a quality improver.

[0056] S1. Select mussels from the sea area of ​​Gouqi Township, Shengsi County, Zhoushan City, Zhejiang Province. Use a brush roller machine to clean them. Each cleaning session lasts 8 minutes. Manually inspect and sort the mussels, removing any damaged or dead ones. Select mussels with a shell length of about 8cm for temporary purification in raw water. The temporary purification temperature is 16℃ and the time is 18 hours.

[0057] S2. After temporary holding, the mussels are sorted a second time, and dead individuals with openings exceeding 0.5cm are removed. The mussels after removing the dead individuals are poured into an elevator and heated by a steamer at 100℃ for 1 minute. After steaming, the mussels are processed to extract the meat. First, the two shells are tightly clamped together with the byssal threads, and the byssal threads are quickly pulled off. Then, the adduct connecting the mussel meat to the two shells is cut off with a mussel knife, and the two shells are removed to obtain pure meat mussels.

[0058] S3. Add water equal to 20% of the mussel meat's weight to the bagged mussel meat, then vacuum it to 90% vacuum level, and seal it after vacuuming. Spread the packaged mussel meat flat on a conveyor belt for rapid freezing, and then place it in a freezing liquid tank (freezing liquid temperature is -35℃). After freezing for 15 minutes, remove the mussels from the freezing liquid tank. The freezing liquid is an ultra-low temperature freezing point liquid prepared from calcium chloride, edible salt, and water.

[0059] S4. Store the flash-frozen products in a -18℃ freezer.

[0060] Comparative Example 2:

[0061] The only difference from Example 1 is that instead of using ultra-low temperature liquid containing cryogenic fluid for rapid freezing, conventional spiral freezing is used, with a spiral freezing temperature of -35°C.

[0062] Comparative Example 3:

[0063] The only difference from Example 1 is that the immersion temperature of the quality improvement solution is 20°C.

[0064] Comparative Example 4:

[0065] The only difference from Example 1 is that the quality improvement solution in step S2 is a solution composed of 3 parts sodium citrate, 1 part sodium chloride, and 990 parts water.

[0066] Comparative Example 5:

[0067] The only difference from Example 1 is that the quality improvement solution in step S2 is a solution composed of 6 parts sodium bicarbonate, 1 part sodium chloride, and 990 parts water.

[0068] Comparative Example 6:

[0069] The only difference from Example 1 is that the quality improvement solution in step S2 is a solution composed of 6 parts sodium bicarbonate, 3 parts sodium citrate, and 990 parts water.

[0070] Evaluation comparison of Example 1 with each comparative example:

[0071] To comprehensively evaluate the differences between the examples and the comparative examples, the following metrics were observed:

[0072] (1) Thawing water loss rate

[0073] Thawing water loss rate is a key indicator for evaluating the quality of frozen aquatic products. The better the freezing effect and the less cell damage to the aquatic products, the lower the thawing water loss rate.

[0074]

[0075] Ten bags were taken from each observation group, and the average value was used as the water loss rate of that group of samples.

[0076] (2) Volatile basic nitrogen (TVB-N)

[0077] Volatile basic nitrogen (TVB-N) is a key indicator for measuring the freshness of processed aquatic products. Based on the operating standard GB5009.228-2016, measurements were taken at different time points for the samples of Example 1 and each comparative example to compare the freshness-preserving effect of different processing methods. Ten bags were taken from each group of observations, and the average value was used as the TVB-N value of that group of samples.

[0078] (3) Overall fresh product quality reproduction

[0079] To evaluate the quality of different freezing processing methods for the same type of material, this indicator uses a boiling test as the benchmark. The quality of each test group is assessed by manual tasting and scoring, comparing it to the quality of fresh products. Assuming the fresh product score is 100 points, tasters score the quality of each frozen product after thawing and boiling. The scoring takes into account factors such as fishy smell, sweetness, and chewiness before assigning a percentage score.

[0080] Table 1: Comparison of water loss rate of frozen mussels after thawing in the examples and comparative examples

[0081]

[0082]

[0083] As can be seen from the data in Table 1: Example 1, based on the core process formula of this invention, showed significantly lower water loss rates than the comparative examples under different storage periods; Comparative Example 2 did not use the liquid ultra-low temperature freezing described in this invention but instead used spiral air freezing, resulting in low heat exchange efficiency, excessive time for the mussel meat to pass through the -5℃ to 0℃ ice crystal formation zone, and excessively large ice crystals formed during freezing, which damaged the cell tissue structure, thus resulting in the highest water loss rate; Comparative Example 1 did not use the quality improvement and freshness-locking formula for soaking, resulting in poor moisture retention, and its water loss rate was second only to Comparative Example 2; Comparative Examples 4, 5, and 6 lacked key components in the freshness-locking formula, and their moisture retention effects were significantly improved compared to Example 1; Comparative Example 3 had a higher temperature during the quality improvement solution soaking process, leading to increased oxidation of the mussel meat during soaking and a decrease in the effectiveness of the quality improvement solution, thus its water loss rate was significantly higher than that of Example 1.

[0084] Table 2: Comparison of Freshness Index (TVB-N) of Frozen Mussels After Thawing between Examples and Comparative Examples

[0085]

[0086] As can be seen from the data in Table 2: Example 1, based on the core process formula of this invention, showed significantly lower TVB-N levels than the comparative examples under different storage periods; Comparative Example 2 did not use the liquid ultra-low temperature freezing described in this patent but instead used spiral air freezing, resulting in low heat exchange efficiency, the worst freezing effect, and the highest TVB-N index; Comparative Example 1 did not use the quality improvement and freshness-locking formula for soaking, resulting in poor freshness-locking effect and weak quality retention; Comparative Examples 4, 5, and 6 lacked key components in the freshness-locking formula, and their TVB-N levels were worse than Example 1 but lower than Comparative Examples 1 and 2, with moderate freshness-locking effects; Comparative Example 3 had a higher temperature during the quality improvement liquid soaking stage, which led to a decrease in the freshness of the mussel meat during the soaking stage, thus resulting in a significant increase in TVB-N compared to Example 1.

[0087] Table 3: Comparison of the overall freshness of frozen mussel meat in the examples and comparative examples

[0088]

[0089] As can be seen from the data in Table 3: Example 1, based on the core process formula of this invention, showed significantly better freshness than the comparative examples under different storage periods; Comparative Example 2 did not use the liquid ultra-low temperature freezing described in this patent but used spiral air freezing, resulting in low heat exchange efficiency, the worst freezing effect, the lowest freshness, and rapid quality degradation with prolonged storage time; Comparative Example 1 did not use the quality improvement and freshness-locking formula for soaking, resulting in poor freshness-locking effect and weak quality retention, and also a low freshness; Comparative Examples 4, 5, and 6 lacked key components in the freshness-locking formula, and all showed varying degrees of decline compared to Example 1; Comparative Example 3 had a higher temperature during the quality improvement liquid soaking process, leading to a decrease in the freshness of the mussel meat during soaking, and the freshness was also significantly lower than that of Example 1.

[0090] In summary, this invention enhances the freshness-locking effect through an innovative quality-improving solution and a highly thermally conductive liquid rapid freezing process, resulting in a significant improvement in the quality of frozen mussel products. This innovative method not only solves the problems of severe juice loss and poor freshness commonly found in traditional freezing technologies, but also effectively extends the shelf life of food, achieving a "fresh-grade" freezing and freshness-locking effect. This technological system provides a completely new solution for the frozen processing of mussels and other aquatic animals with high moisture content, and has broad prospects for industrial application.

[0091] The technical means disclosed in this invention are not limited to those described above, but also include technical solutions composed of any combination of the above technical features. The above descriptions are specific embodiments of this invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

[0092] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method of producing frozen mussels, characterized by, The method comprises the following steps: S1, removing impurities and temporary purification treatment of the mussels; S2, secondary sorting of the mussels after temporary purification treatment, removing dead individuals, and then cooking and enzyme inactivation treatment of the mussels after removing dead individuals, and then peeling the mussel meat; S3, rinsing the mussel meat in salt water, and then soaking in a quality improvement liquid; S4, then plastic packaging of the mussel meat, and then rapid freezing; S5, finally, cold storage of the frozen mussel meat.

2. The method of producing frozen mussels according to claim 1, characterized in that, Step S1 uses seawater from the original habitat of the mussels for temporary cultivation of the mussels for 12-36 hours, and the water temperature is 10-18℃.

3. The method of producing frozen mussels according to claim 1, wherein Step S2, the temperature for enzyme inactivation treatment is 80-100℃, and the time is 1-3min.

4. The method of producing frozen mussels according to claim 1, wherein Step S3, the soaking temperature is 5-10℃, and the time is 2-4h.

5. The method of producing frozen mussels according to claim 1, wherein Step S3, the quality improvement liquid comprises the following raw materials by mass fraction: 0.6-0.7 parts of sodium bicarbonate, 0.3-0.5 parts of sodium citrate, 0.1-0.3 parts of sodium chloride, and 98.5-99 parts of water.

6. The method of producing frozen mussels according to claim 1, wherein Step S4, the plastic packaging specifically comprises: after the mussel meat is packed, 10-20% of the mass of the mussel meat is added, and then vacuumed to 80-95% vacuum degree.

7. The method of producing frozen mussels according to claim 1, wherein Step S4, rapid freezing using an ultra-low temperature rapid freezing device, wherein the ultra-low temperature rapid freezing device contains a freezing liquid with an ice point ≤50℃, and the freezing liquid comprises the following raw materials by mass fraction: 40-50 parts of sodium chloride, 10-15 parts of calcium chloride, and 50-100 parts of water.

8. A method of producing frozen mussels according to claim 7, characterized in that, The temperature of the freezing liquid is ≤-35℃, the rapid freezing time is 10-20min, and the rapid freezing rate is ≥5℃ / min.

9. The method of producing frozen mussels according to claim 1, wherein After step S4, the average particle size of ice crystal particles in the mussel meat is <50μm.

10. The method of producing frozen mussels according to claim 1, wherein The cold storage temperature is -(10-25)℃.

Images