Ultralow temperature aquatic product origin stock solution instant freezing preparation process

Abstract

The invention provides an instant freezing preparation process of ultralow-temperature aquatic product origin stock solution. The instant freezing preparation process comprises the following steps: (a) cleaning; (b) freezing: putting the aquatic products into ultralow-temperature liquid medium instant freezing equipment, wherein the equipment comprises a freezing bin, a storage container, a circulating pump and a refrigerant circulating loop; a refrigerating medium with the freezing point lower than-60 DEG C is poured into the freezing bin, the freezing bin and the circulating pump form a refrigerating medium circulating loop through a pipeline, and heat exchange is conducted between the refrigerant circulating loop and the refrigerating medium circulating loop; the aquatic products and the stock solution in the production place are put into a storage container and placed in a freezing bin, at least part of the storage container is immersed into the refrigerating medium, the aquatic products and the refrigerating medium are isolated through the storage container, the temperature of the freezing bin is 50 DEG C below zero to 55 DEG C below zero, and the freezing time is 8-20 min; and (c) taking out the frozen aquatic product. The liquid cooling technology and the original liquid in the production place are synchronously added and combined to achieve ultralow-temperature freezing, the freezing speed is high, and the freshness, the taste and the nutritive value are kept to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of aquatic product fresh-keeping and freezing, and particularly relates to a preparation process for directly freezing the original liquid of aquatic products at the place of origin at ultra-low temperature. Background Art

[0002] In traditional freezing technologies in the fields of aquatic products and food processing, air is mainly used as the cooling medium. For example, freezing equipment such as refrigerators, commercial freezers, and cold storages. Although the technology is mature, it has obvious defects. First, the heat conduction efficiency of air is low, resulting in a slow freezing speed. Usually, it takes more than ten hours to complete the freezing process, which not only reduces production efficiency but also easily causes large ice crystals to form inside food cells, damaging the cell structure and affecting the taste of food and causing a large loss of nutritional value. For example, in the freezing of aquatic products, the slow freezing process will cause the cell walls of aquatic products such as fish and shrimp to rupture, and a large amount of juice will be lost after thawing, greatly reducing the flavor and texture. Second, the energy consumption of traditional freezing methods is relatively high. Due to the limited cooling capacity of air, the equipment needs to run for a long time to maintain a low-temperature environment, resulting in energy waste, which is particularly obvious in large cold storages and commercial freezers. Therefore, there is an urgent need to develop a more efficient and energy-saving freezing technology to meet the growing demand for rapid freezing and high-quality fresh-keeping in the modern food industry and aquatic product processing. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the above problems and provide a preparation process for directly freezing the original liquid of aquatic products at the place of origin at ultra-low temperature, which has a fast freezing speed, energy conservation and consumption reduction, improves the freezing taste, and greatly improves the freezing efficiency and fresh-keeping effect.

[0004] The present invention provides a preparation process for directly freezing the original liquid of aquatic products at the place of origin at ultra-low temperature, which is characterized by including the following steps: (a) Cleaning; (b) Freezing: putting the aquatic products into an ultra-low temperature liquid medium direct-freezing device, the ultra-low temperature liquid medium direct-freezing device including a freezing chamber, a storage container, a circulation pump, and a refrigerant circulation circuit; filling a coolant with a freezing point lower than -60°C in the freezing chamber, forming a coolant circulation circuit through pipelines between the freezing chamber and the circulation pump, and performing heat exchange between the refrigerant circulation circuit and the coolant circulation circuit; putting the aquatic products and the original liquid at the place of origin into the storage container and placing them in the freezing chamber, at least part of the storage container being immersed in the coolant and isolating the aquatic products and the coolant through the storage container, controlling the temperature of the freezing chamber to be -50°C to -55°C, and the freezing time to be 8 - 20 min; (c) Taking out the frozen aquatic products.

[0005] The process steps of the present invention are clear and easy to realize industrial production, integrating the advantages of high-efficiency ultra-low temperature liquid cooling, fresh-keeping of the original liquid at the place of origin, and isolation protection, significantly improving the freezing efficiency and maintaining the freshness and texture of food.

[0006] Furthermore, in the process for instant freezing of the original liquid of aquatic products at ultra-low temperature in the place of origin according to the present invention, the storage container uses a freezing mold, which is detachably fixed in the freezing chamber. The interior of the freezing mold is isolated from the coolant. The aquatic products and the original liquid of the place of origin are jointly loaded into the freezing mold, and the original liquid of the place of origin submerges the aquatic products by 2-3 cm. Using a freezing mold has good uniform freezing property, unified product specifications, and is suitable for mass production.

[0007] Furthermore, in the process for instant freezing of the original liquid of aquatic products at ultra-low temperature in the place of origin according to the present invention, when the freezing mold is placed in the freezing chamber, the liquid level of the coolant is 3-5 cm higher than the materials in the freezing mold, and the outer bottom surface of the freezing mold does not contact the inner bottom surface of the freezing chamber, ensuring that the coolant fully contacts the outer wall of the mold and improving the heat exchange efficiency.

[0008] Furthermore, in the process for instant freezing of the original liquid of aquatic products at ultra-low temperature in the place of origin according to the present invention, a temperature measuring hole is provided on the freezing mold. The thermometer is inserted into the temperature measuring hole to measure the central temperature of the aquatic products. When the central temperature reaches -40°C to -50°C, step (c) is implemented to ensure that the freezing effect reaches the best state.

[0009] Furthermore, in the process for instant freezing of the original liquid of aquatic products at ultra-low temperature in the place of origin according to the present invention, the storage container uses a sealed packaging bag. A hollow storage basket is installed in the freezing chamber. The aquatic products and the original liquid of the place of origin are jointly loaded into the sealed packaging bag. The weight of the original liquid of the place of origin is 10-15% of the weight of the aquatic products. After vacuumizing and sealed packaging, it is placed in the storage basket and immersed in the coolant. The coolant submerges the sealed packaging bag. Using a sealed packaging bag for vacuum isolation saves the dosage of the original liquid while maintaining the frozen quality and freshness, and is suitable for aquatic products of different specifications and shapes, with a wide application range and space saving.

[0010] Furthermore, in the process for instant freezing of the original liquid of aquatic products at ultra-low temperature in the place of origin according to the present invention, step (c) includes: taking out the sealed packaging bag, dehydrating and removing the residual coolant on the surface and recycling it, ensuring that the surface of the packaging bag is clean, facilitating subsequent storage and transportation, while reducing the waste of the coolant and lowering the cost.

[0011] Furthermore, in the process for instant freezing of the original liquid of aquatic products at ultra-low temperature in the place of origin according to the present invention, a pre-cooling step is also included before step (b): putting the aquatic products into a pre-cooling pool, pre-cooling to 3°C - 5°C, and the pre-cooling time is 10-20 min, reducing thermal shock and improving the freezing efficiency.

[0012] Furthermore, in the ultra-low temperature aquatic product origin stock solution instant freezing preparation process of the present invention, the origin stock solution at 3°C - 5°C is used as the precooling medium in the precooling pool. A conveyor line is also provided in the precooling pool. The aquatic products continuously move and are soaked in the precooling pool through the conveyor line. Applying the origin stock solution to the precooling link can further maintain the flavor and nutritional components of the aquatic products. Combined with the continuous operation of the conveyor line, it is suitable for large-scale production and improves efficiency.

[0013] Furthermore, in the ultra-low temperature aquatic product origin stock solution instant freezing preparation process of the present invention, before step (b), there is also a step of physically precipitating, filtering, and purifying the origin stock solution to remove impurities and microorganisms.

[0014] Furthermore, in the ultra-low temperature aquatic product origin stock solution instant freezing preparation process of the present invention, in step (a), the cleaning time is 5 - 15 min, and the cleaning temperature is 10 - 15°C.

[0015] The beneficial effects of the present invention are as follows: 1. The present invention aims at the field of frozen preservation of aquatic products. It adopts advanced liquid cooling technology and uses a liquid coolant with a freezing point lower than -60°C as the medium to conduct heat exchange with the aquatic products, replacing the traditional air cooling method. It has a higher heat conduction efficiency, can quickly cool the aquatic products to an ultra-low temperature state, reduce the damage of ice crystals to the cell structure of the aquatic products, and has a significant energy-saving effect.

[0016] 2. The present invention freezes while adding the origin stock solution to the aquatic products. At the same time, the precooling process also uses the origin stock solution for soaking, ensuring that it matches the flavor and nutritional components of the aquatic products, better locking in the natural flavor of the aquatic products, avoiding taste loss caused by the freezing process, and maximizing the preservation of food freshness, taste, and nutritional components.

[0017] 3. The present invention can use a freezing mold or a sealed packaging bag as the storage container, which can not only effectively isolate the coolant and the aquatic products, avoid direct contact, prevent contamination, and ensure food safety and hygiene, but also can be flexibly selected according to different production requirements and market positions to meet diverse application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the ultra-low temperature liquid medium instant freezing equipment described in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be further described below in conjunction with the drawings: Example 1

[0020] This example discloses the above-mentioned ultra-low temperature aquatic product origin stock solution instant freezing preparation process, which includes the following steps.

[0021] (a) Cleaning: Remove the surface impurities and microorganisms of the aquatic product. The cleaning time is 5 - 15 min, and the cleaning temperature is 10 - 15 °C.

[0022] Perform physical precipitation, filtration, and purification on the original liquid from the origin of the aquatic product to remove impurities and microorganisms.

[0023] Pre - cooling: Place the aquatic product in a pre - cooling tank. The original liquid from the origin at 3 °C - 5 °C is used as the pre - cooling medium in the pre - cooling tank. There is also a conveyor line in the pre - cooling tank. The aquatic product continuously moves and is soaked in the pre - cooling tank through the conveyor line and is pre - cooled to 3 °C - 5 °C. The pre - cooling time is 10 - 20 min; (b) Freezing: Place the aquatic product in a cryogenic liquid medium instant - freezing device. As shown in Figure 1 , the cryogenic liquid medium instant - freezing device includes a freezing chamber 1, a freezing mold 2, a circulation pump 3, and a refrigerant circulation circuit 4. Pour a coolant with a freezing point lower than - 60 °C into the freezing chamber 1. It is selected as a colorless, odorless, and non - flammable liquid. The freezing chamber and the circulation pump form a coolant circulation circuit 5 through pipelines, and the refrigerant circulation circuit 4 exchanges heat with the coolant circulation circuit 5.

[0024] Put the aquatic product and the original liquid from the origin together into the freezing mold 2. The original liquid from the origin submerges the aquatic product by 2 - 3 cm. By adding the original liquid from the origin, it can ensure that it matches the flavor and nutritional components of the aquatic product, and ensure the flavor and texture of the product after freezing. The specific addition method can be step - by - step and alternately added in the order of "aquatic product → original liquid → aquatic product → original liquid", added layer by layer and ensure that the original liquid evenly covers and penetrates the aquatic product, so that the aquatic product is in full contact with the original liquid.

[0025] Detachably fix the freezing mold 2 to the inside of the freezing chamber 1 and at least part of the freezing mold 2 is immersed in the coolant. The inside of the freezing mold 2 is isolated from the coolant. After the freezing mold 2 is installed, the liquid level of the coolant is 3 - 5 cm higher than the material in the freezing mold 2, and the outer bottom surface of the freezing mold 2 does not contact the inner bottom surface of the freezing chamber 1. Control the temperature of the freezing chamber 1 at - 50 °C - - 55 °C, and the freezing time is 8 - 20 min.

[0026] There is a temperature - measuring hole on the freezing mold 2. Insert a thermometer into the temperature - measuring hole and measure the central temperature of the aquatic product. When the central temperature reaches - 40 °C - - 50 °C, perform step (c).

[0027] (c) Take out the frozen aquatic product: Take out the freezing mold 2 and perform demolding on the aquatic product. The thermal demolding method can be used, which has good demolding effect and high demolding integrity.

[0028] The preparation process disclosed in this embodiment is applicable to the rapid freezing of aquatic products such as fish, shrimps, and shellfish. Using a liquid coolant with a low freezing point as the medium, the heat conduction efficiency is much higher than that of air, which can transfer cold more efficiently and quickly cool the aquatic products in the freezing mold 2 to an ultra-low temperature state. The freezing time only takes more than ten minutes, significantly reducing the damage of ice crystals to the cell structure of aquatic products and being more energy-saving and consumption-reducing. At the same time, the present invention combines the synchronous addition of the origin stock solution during the freezing process, enabling the full integration of the stock solution with the flavor and nutritional components of the aquatic products, maximizing the preservation of the freshness, taste, and nutritional value of the food, ensuring that the product still maintains its original flavor after thawing, achieving high-quality frozen preservation, and meeting the requirements of the food industry for efficient and high-quality freezing. Example 2

[0029] The difference between this embodiment and Embodiment 1 is that in step (b), instead of using the freezing mold 2, a hollow storage basket is installed in the freezing chamber 1. The aquatic products and the origin stock solution are jointly packed into a sealed packaging bag. The weight of the origin stock solution is 10 - 15% of the weight of the aquatic products. After vacuumizing and sealing the packaging, it is placed in the storage basket and immersed in the coolant, and the coolant covers the sealed packaging bag.

[0030] The said step (c) includes: taking out the sealed packaging bag, dehydrating to remove the residual coolant on the surface and recycling it.

[0031] The process of this embodiment uses vacuum isolation in the sealed packaging bag followed by ultra-low temperature freezing, which has the advantages of vacuum preservation, space saving, less usage of the stock solution, and flexible adaptation to different shapes.

[0032] The specific embodiments described herein are only illustrative of the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the relevant technical field without departing from the spirit and technical ideas disclosed by the present invention are still covered by the claims of the present invention.

Claims

1. A process for preparing frozen stock solution of ultra-low temperature aquatic products at the origin, characterized in that: The steps include: Cleaning; Freezing: Put the aquatic product into an ultra-low temperature liquid medium freezing device, which includes a freezing chamber, a storage container, a circulating pump, and a refrigerant circulation loop; pour a refrigerant with a freezing point below -60°C into the freezing chamber, and the freezing chamber and the circulating pump form a refrigerant circulation loop through pipelines, and the refrigerant circulation loop and the refrigerant circulation loop perform heat exchange; put the aquatic product and the original liquid from the place of origin into a storage container and place it in the freezing chamber, the storage container is at least partially immersed in the refrigerant and the aquatic product and the refrigerant are isolated by the storage container, the freezing chamber temperature is controlled to be above -50°C--55°C, and the freezing time is 8-20min; Take out the frozen seafood.

2. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 1, characterized in that: The storage container adopts a freezing mold, which can be detachably fixed in the freezing chamber. The interior of the freezing mold is isolated from the coolant. The aquatic product and the original liquid from the origin are put into the freezing mold together, and the original liquid from the origin covers the aquatic product by 2-3 centimeters.

3. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 2, characterized in that: When the freezing mold is placed in the freezing chamber, the liquid level of the coolant is 3-5 centimeters higher than the material in the freezing mold, and the outer bottom surface of the freezing mold does not contact the inner bottom surface of the freezing chamber.

4. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 2 or 3, characterized in that: The freezing mold is provided with a temperature measuring hole, a thermometer is inserted into the temperature measuring hole and the center temperature of the aquatic product is measured, and when the center temperature reaches -40°C to 50°C, step (c) is implemented.

5. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 1, characterized in that: The storage container adopts a sealed packaging bag, and a hollow storage basket is installed in the freezing warehouse. The aquatic product and the original liquid from the origin are put into the sealed packaging bag together. The weight of the original liquid from the origin is 10-15% of the weight of the aquatic product. After vacuuming and sealing, it is placed in the storage basket and immersed in a coolant, and the coolant covers the sealed packaging bag.

6. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 5, characterized in that: The step (c) comprises: taking out the sealed packaging bag, dehydrating and removing the coolant remaining on the surface and recycling it.

7. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 1, characterized in that: The step (b) also includes a precooling step: placing the aquatic product in a precooling tank and precooling it to 3°C-5°C for 10-20 minutes.

8. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 7, characterized in that: The precooling pool uses 3°C-5°C original liquid from the place of origin as the precooling medium. The precooling pool is also provided with a conveying line, and the aquatic products are continuously moved and immersed in the precooling pool through the conveying line for precooling.

9. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 1, characterized in that: Before step (b), the method also includes the steps of physically precipitating, filtering and purifying the raw liquid from the origin to remove impurities and microorganisms.

10. The process for preparing frozen stock solution of ultra-low temperature aquatic products according to claim 1, characterized in that: In step (a), the cleaning time is 5-15 minutes and the cleaning temperature is 10-15°C.

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