Food-grade refrigerating fluid for dipping and quick-freezing

Abstract

The invention relates to a food-grade refrigerating fluid for dipping and quick-freezing. The food-grade refrigerating fluid for dipping and quick freezing comprises the following components: 95 ethanol, propylene glycol, betaine, calcium chloride and distilled water / deionized water, the cleaning agent comprises the following components in percentage by mass: 20%-30% of 95 ethanol, 10%-15% of propylene glycol, 5%-10% of betaine, 0%-0.5% of calcium chloride and the balance of pure water. The refrigerating fluid is extremely low in corrosion to metal equipment and higher in specific heat capacity and heat conductivity coefficient under the condition that the requirement for dipping and quick freezing at the temperature of-30 DEG C or below is met, the cold storage capacity and heat exchange capacity of the refrigerating fluid at the low temperature can be greatly improved, the effect of reducing production energy consumption is achieved in the early stage of production and in the production process, and the production cost is reduced. And the freezing liquid is lower in viscosity and better in flowability.

Description

Technical Field

[0001] The present application relates to the technical field of immersion quick freezing, and in particular to a food-grade freezing liquid for immersion quick freezing. Background Art

[0002] Freezing is an effective way to preserve food, but the traditional freezing method has disadvantages such as slow freezing rate, low heat transfer coefficient, and small and coarse ice crystals, which leads to poor quality of frozen products. Improving the freezing rate is an effective way to solve such problems. Immersion quick freezing technology uses low-temperature freezing liquid (generally -30°C) as a cooling medium to directly or indirectly contact the food to achieve rapid cooling and freezing of the food. Compared with other freezing technologies, immersion quick freezing has a higher freezing rate, which can shorten the maximum ice crystal formation zone (-1°C to 5°C) during the quick freezing of food, reduce the damage of ice crystals to the internal structure of the food, maintain the frozen quality of the food and extend the shelf life of the food, thereby achieving higher commercial value.

[0003] Immersion quick freezing uses liquid as a heat transfer medium. Compared with the common cold air freezing method using air as a medium, the thermal conductivity of immersion quick freezing will be greatly improved, the heat transfer efficiency will be improved, the freezing time will be reduced, and the freezing quality of food will be improved and its product quality will be extended. As an important heat transfer medium for immersion quick freezing technology, low-temperature freezing liquid is a key component of immersion quick freezing technology. The ideal low-temperature freezing liquid should have the advantages of high thermal conductivity, low freezing point, reasonable specific heat capacity and viscosity, and low cost. These characteristics mainly depend on the composition and ratio of the freezing liquid.

[0004] At present, all the freezing liquids on the market use a large amount of sodium chloride (salts) to enable the mixture to remain liquid at a lower temperature. After long-term experimental research and observation, the inventors found that during long-term use, a type of freezing liquid with a high sodium chloride (salt) content is more corrosive to metal equipment and will affect the service life of the metal equipment; in addition, when the freezing point meets the -30°C immersion quick freezing process, there are generally disadvantages of low specific heat capacity and low thermal conductivity, and the cold storage capacity and heat exchange capacity at low temperatures are weak. Summary of the invention

[0005] Based on this, the present application provides a food-grade freezing liquid for immersion quick freezing. The freezing liquid ratio meets the -30°C immersion quick freezing processing requirements, has extremely low corrosion to metal equipment, has higher specific heat capacity and thermal conductivity, can greatly enhance the freezing liquid's cold storage capacity and heat exchange capacity at low temperatures, and plays a role in reducing production energy consumption in the early stage and during the production process. In addition, the freezing liquid has lower viscosity and better fluidity.

[0006] The present application provides a food-grade freezing liquid for immersion quick freezing, comprising the following components: 95% ethanol, propylene glycol, betaine, calcium chloride, and pure water; the mass percentage of each component is: 95% ethanol 20% to 30%, propylene glycol 10% to 15%, betaine 5% to 10%, calcium chloride 0% to 0.5%, and the balance is pure water.

[0007] In one embodiment, the working temperature of the freezing liquid is -32°C to -34°C, and its components, by mass percentage, are: 20% 95 ethanol, 10% to 15% propylene glycol, 5% betaine, 0.5% calcium chloride, and the balance is pure water.

[0008] In one embodiment, the working temperature of the freezing liquid is -35°C to -41°C, and its components, by mass percentage, are: 20% 95 ethanol, 10% to 15% propylene glycol, 10% betaine, 0.5% calcium chloride, and the balance is pure water.

[0009] In one embodiment, when the working temperature of the freezing liquid is -39°C to -41°C, its components are as follows by mass percentage: 95 ethanol 20% to 30%, propylene glycol 15%, betaine 5% to 10%, and the balance is pure water.

[0010] In one embodiment, the pure water is distilled water or deionized water.

[0011] Compared with the prior art, a food-grade freezing liquid for immersion quick freezing in an embodiment of the present application has the following advantages and beneficial effects: the present invention selects food-grade 95 ethanol, propylene glycol, betaine, calcium chloride, and distilled water / deionized water to form a mixed aqueous solution. Without using sodium chloride, the -30°C immersion quick freezing condition is met by adjusting the distribution ratio of other components, thereby effectively avoiding the corrosion of metal equipment caused by sodium chloride; the freezing liquid after adjusting the distribution ratio of each component has a higher specific heat capacity and thermal conductivity, which can greatly enhance the cold storage capacity and heat exchange capacity of the freezing liquid at low temperatures, and effectively reduce the production energy consumption and production cost in the early stage and during the production process; and the freezing liquid has lower viscosity and better fluidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the freezing temperature and freezing curve of the refrigerant in Example 1 of the present application;

[0013] Figure 2 A schematic diagram of the freezing temperature and freezing curve of the refrigerant in Example 2 of the present application;

[0014] Figure 3 This is a schematic diagram of the freezing temperature and freezing curve of the refrigerant in Example 3 of the present application;

[0015] Figure 4 A schematic diagram of the freezing temperature and freezing curve of the refrigerant in Example 4 of the present application;

[0016] Figure 5 This is a schematic diagram of the freezing temperature and freezing curve of the refrigerant in Example 5 of the present application;

[0017] Figure 6 This is a schematic diagram of the freezing temperature and freezing curve of the refrigerant in Example 6 of the present application;

[0018] Figure 7 This is a viscosity comparison chart of the freezing liquid of Examples 1-6 of the present application (25°C and -30°C);

[0019] Figure 8 The specific heat capacity diagram of the refrigerant of Examples 1-6 of the present application (-5°C to -35°C);

[0020] Fig. 9 This is a graph of thermal conductivity of the refrigerant of Examples 1-6 of the present application (-5°C to -35°C). DETAILED DESCRIPTION

[0021] Here, the exemplary embodiments will be described in detail, and the examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. Moreover, the implementations described in the following exemplary embodiments do not limit the present invention, and the structural, methodological, or functional changes made by ordinary technicians in the field according to these implementations are all included in the protection scope of the present invention.

[0022] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0023] It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0024] In order to better illustrate the technical solutions and technical effects of the embodiments of the present application, relevant prior arts are now described with examples.

[0025] Prior art 1: The patent with publication number CN102241964B and patent name "Quinternary Coolant for Food Immersion Freezing" discloses a quaternary coolant composed of ethanol, sodium chloride, water, and water-soluble protein. When the immersion freezing working temperature is above -20℃, the refrigerant components are: 5%~8% ethanol, 20% sodium chloride, 0.5% water-soluble protein, and the balance is water; when the immersion freezing working temperature is above -30℃, the refrigerant components are 23%~25% ethanol, 14%~20% sodium chloride, 0.5% water-soluble protein, and the balance is water; when the immersion freezing working temperature is above -40℃, the refrigerant components are 37%~40% ethanol, 12%~15% sodium chloride, 0.5% water-soluble protein, and the balance is water; when the immersion freezing working temperature is between -44 and -40℃, the refrigerant components are 43%~45% ethanol, 5%~14% sodium chloride, 0.3%~0.5% water-soluble protein, and the balance is water.

[0026] Prior art 2: The application document with application number CN201010204636.X and titled "Quaternary Coolant for Food Immersion Freezing" discloses a quaternary coolant, which is composed of ethanol, propylene glycol, sodium chloride and water. When the immersion freezing working temperature is higher than -30°C, the coolant preferably contains an aqueous solution of 20% to 25% ethanol, 10% to 35% propylene glycol, and 3% to 12% sodium chloride by weight percentage; when the working temperature is higher than -40°C and lower than -30°C, the coolant used preferably contains an aqueous solution of 20% to 25% ethanol, 18% to 35% propylene glycol, and 4% to 12% sodium chloride by weight percentage; when the working temperature is higher than -44°C and lower than -40°C, the coolant used preferably contains an aqueous solution of 20% to 25% ethanol, 25% to 35% propylene glycol, and 4% to 10% sodium chloride by weight percentage.

[0027] Prior art 3: The application document with application number CN201711038993.1 and name "A kind of indirect immersion freezing liquid for conditioning steak" discloses a immersion freezing liquid. The indirect immersion freezing liquid for conditioning steak includes the following components by mass percentage: 26% to 30% ethanol; 8% to 12% betaine; 6% to 10% propylene glycol; 3% to 5% sodium chloride; 43% to 57% water; the freezing point of the freezing liquid is -57.5°C; the viscosity of the freezing liquid at -30°C is 66.7mPa.s.

[0028] Prior art 4: A patent with publication number CN102719229B and patent name "A freezing liquid for direct immersion and freezing of food" discloses a freezing liquid, which mainly includes the following components in percentage by mass: 18% to 35% betaine, 15% to 20% edible alcohol with a concentration of more than 95%, 2% to 8% sodium chloride, and the remainder is water.

[0029] The freezing liquid disclosed in the above-mentioned prior art has the following shortcomings: the content of sodium chloride (salts) is relatively high, and it is highly corrosive to metal equipment when used for a long time; when meeting the requirements of -30°C immersion quick freezing, the specific heat capacity is roughly maintained at 2.6J / (g·℃)~2.7J / (g·℃), and the thermal conductivity is approximately 0.3044W / (m·℃).

[0030] In response to the technical problems mentioned in the prior art, an embodiment of the present application provides a food-grade freezing liquid for immersion quick freezing. The freezing liquid meets the -30°C immersion quick freezing requirements by adjusting the proportions of other components without using sodium chloride, and has higher specific heat capacity and thermal conductivity. It can greatly enhance the cold storage capacity and heat exchange capacity of the freezing liquid at low temperatures, play a role in reducing production energy consumption in the early stage of production and during the production process, and the freezing liquid has lower viscosity and better fluidity.

[0031] Hereinafter, a food-grade freezing liquid for immersion quick freezing according to an embodiment of the present invention will be described in more detail, but the present invention should not be limited thereto.

[0032] The embodiment of the present application provides a food-grade freezing liquid for immersion and quick freezing. The freezing liquid can be used for immersion and quick freezing of foods such as lychees, and can also be used for immersion and quick freezing of other items in the fields of biomedicine, chemistry, etc. This embodiment does not limit the application field.

[0033] The food-grade freezing liquid for soaking quick-frozen food provided in the embodiment of the present application comprises the following components: 95 ethanol, propylene glycol, betaine, calcium chloride, and pure water; the mass percentage of each component is: 95 ethanol 20% to 30%, propylene glycol 10% to 15%, betaine 5% to 10%, calcium chloride 0% to 0.5%, and the balance is pure water. The raw materials of each component of the freezing liquid in this embodiment are all food grade, and after being fully mixed and matched, it is used as the freezing liquid for soaking quick-frozen food. The pure water in the embodiment of the present application is preferably distilled water or deionized water.

[0034] The application method of the freezing liquid in the embodiment of the present application is: put the prepared freezing liquid into the storage tank of the immersion quick freezing machine, start the immersion quick freezing machine to cool the freezing liquid to the set working temperature (below -30°C), then immerse the material in the freezing liquid for freezing, and take out the material after the material reaches the freezing target center temperature (-18°C).

[0035] Compared with the prior art, a food-grade freezing liquid for immersion quick freezing in an embodiment of the present application has the following advantages and beneficial effects: the present invention selects food-grade 95 ethanol, propylene glycol, betaine, calcium chloride, and distilled water / deionized water to form a mixed aqueous solution. Without using sodium chloride, the -30°C immersion quick freezing condition is met by adjusting the distribution ratio of other components, thereby effectively avoiding the corrosion of metal equipment caused by sodium chloride; the freezing liquid after adjusting the distribution ratio of each component has a higher specific heat capacity and thermal conductivity, which can greatly enhance the cold storage capacity and heat exchange capacity of the freezing liquid at low temperatures, and effectively reduce the production energy consumption and production cost in the early stage and during the production process; and the freezing liquid has lower viscosity and better fluidity.

[0036] In the immersion quick freezing technology, the freezing point of the freezing liquid is an important indicator for judging the freezing liquid, while the viscosity, specific heat capacity and thermal conductivity are used to judge the fluidity, cold storage capacity and heat transfer efficiency of the freezing liquid in the working process under low temperature conditions.

[0037] The following describes in detail the composition ratio and various performance indicators of the food-grade freezing liquid for immersion quick freezing in the embodiments of the present application through several specific examples.

[0038] Example 1

[0039] The food-grade freezing liquid used for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -32°C. Its components are as follows by mass percentage: 95 ethanol 20%, propylene glycol 10%, betaine 5%, calcium chloride 0.5%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. After testing, the freezing temperature of the freezing liquid is -32°C, and the freezing curve is as follows Figure 1 Its viscosity, specific heat capacity and thermal conductivity are shown in Figure 7 , 8 The corresponding example of 9 is Figure 7 , 8 In , 9, lowercase letters indicate intra-group differences, which are all less than 0.05; adding a small percentage of calcium chloride can play a hygroscopic and antifreeze role, which can absorb a small amount of moisture and prevent the moisture from forming ice crystals to damage the equipment.

[0040] Example 2

[0041] The food-grade freezing liquid used for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -34°C. Its components are as follows by mass percentage: 95 ethanol 20%, propylene glycol 15%, betaine 5%, calcium chloride 0.5%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. After testing, the freezing temperature of the freezing liquid is -34°C, and the freezing curve is as follows Figure 2 Its viscosity, specific heat capacity and thermal conductivity are shown in Figure 7 ,8 Corresponding example to 9; adding a small percentage of calcium chloride can play a hygroscopic and antifreeze role, which can absorb a small amount of moisture and prevent the moisture from forming ice crystals to damage the equipment.

[0042] Example 3

[0043] The food-grade freezing liquid used for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -35°C. Its components are as follows by mass percentage: 95 ethanol 20%, propylene glycol 10%, betaine 10%, calcium chloride 0.5%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. After testing, the freezing temperature of the freezing liquid is -35°C, and the freezing curve is as follows Figure 3 Its viscosity, specific heat capacity and thermal conductivity are shown in Figure 7 , 8 Corresponding example to 9; adding a small percentage of calcium chloride can play a hygroscopic and antifreeze role, which can absorb a small amount of moisture and prevent the moisture from forming ice crystals to damage the equipment.

[0044] Example 4

[0045] The food-grade freezing liquid used for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -41°C. Its components are as follows by mass percentage: 95 ethanol 20%, propylene glycol 15%, betaine 10%, calcium chloride 0.5%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. After testing, the freezing temperature of the freezing liquid is -41°C, and the freezing curve is as follows Figure 4 Its viscosity, specific heat capacity and thermal conductivity are shown in the attached Figure 7 , 8 Corresponding example to 9; adding a small percentage of calcium chloride can play a hygroscopic and antifreeze role, which can absorb a small amount of moisture and prevent the moisture from forming ice crystals to damage the equipment.

[0046] Example 5

[0047] The food-grade freezing liquid used for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -39°C. Its components are as follows by mass percentage: 95 ethanol 20%, propylene glycol 15%, betaine 10%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. After testing, the freezing temperature of the freezing liquid is -39°C, and the freezing curve is as follows Figure 5 Its viscosity, specific heat capacity and thermal conductivity are shown in the attached Figure 7 , 8 and 9 corresponding examples.

[0048] Example 6

[0049] The food-grade freezing liquid used for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -41°C. Its components are as follows by mass percentage: 95 ethanol 30%, propylene glycol 15%, betaine 5%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. After testing, the freezing temperature of the freezing liquid is -41°C, and the freezing curve is as follows Figure 6 Its viscosity, specific heat capacity and thermal conductivity are shown in the attached Figure 7 , 8 and 9 corresponding examples.

[0050] The following Examples 7-9 are used to detect the endpoint values ​​of the above Examples.

[0051] Example 7, a food-grade freezing liquid for immersion quick freezing, which can be used for immersion quick freezing work at a working temperature not lower than -32°C, and its components are respectively as follows: 95 ethanol 20%, propylene glycol 12%, betaine 5%, calcium chloride 0.5%, and the balance is distilled water / deionized water, and the above components are fully mixed to prepare the freezing liquid. After testing, the freezing temperature of the freezing liquid is -33°C, and its viscosity, specific heat capacity and thermal conductivity are respectively between Example 1 and Example 2.

[0052] Example 8

[0053] The food-grade freezing liquid for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -35°C. The components thereof are as follows by mass percentage: 95 ethanol 20%, propylene glycol 12%, betaine 10%, calcium chloride 0.5%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. According to the test, the freezing temperature of the freezing liquid is -38°C, and its viscosity, specific heat capacity and thermal conductivity are respectively between Example 3 and Example 4.

[0054] Example 9

[0055] The food-grade freezing liquid for immersion quick freezing can be used for immersion quick freezing work at a working temperature not lower than -35°C. The components thereof are as follows by mass percentage: 95 ethanol 25%, propylene glycol 15%, betaine 7%, and the balance is distilled water / deionized water. The above components are fully mixed to prepare the freezing liquid. According to the test, the freezing temperature of the freezing liquid is -40°C, and its viscosity, specific heat capacity and thermal conductivity are respectively between Example 5 and Example 6.

[0056] It can be seen from the freezing liquid ratio in the above embodiments that 95% ethanol is the main component, the raw materials are simple and the cost is low; the content of calcium chloride (salt component) accounts for a maximum of 0.5%, which can effectively reduce the corrosion of the salt component to metal equipment; various freezing liquid components are food grade, which is safer and more reliable in production and processing.

[0057] Through comparative analysis, it can be seen that compared with the freezing liquid in the prior art, under the immersion quick freezing working conditions below -30℃:

[0058] The specific heat capacity of traditional refrigerants is roughly maintained at 2.6J / (g·℃)~2.7J / (g·℃), while the specific heat capacity of the refrigerants with six ratios in the embodiments of the present application ranges from 3J / g·℃ to 4.7J / g·℃, an increase of 15% to 74%. The higher specific heat capacity has better thermal energy storage capacity, temperature stability and energy-saving effect.

[0059] The thermal conductivity of traditional refrigerant is about 0.3044W / (m·℃), while the thermal conductivity of the refrigerant formulated in the embodiments of the present application reaches or exceeds 0.4W / (m·℃), an increase of 24% or more. The higher thermal conductivity has better heat exchange efficiency, which can reduce machine power transmission and improve energy efficiency.

[0060] From the perspective of the viscosity of the refrigerant, the viscosity of the refrigerant in the six ratios of the embodiments of the present application is relatively low, about 30 mPa·s to 35 mPa·s. It can be seen that it has better fluidity than traditional refrigerants.

[0061] From the above, it can be seen that the freezing point of the freezing liquid of the present invention can be as low as -41°C, which meets the requirements of immersion quick freezing production below -30°C. The freezing liquids of each embodiment do not contain sodium chloride. By adjusting the proportion of other components, the specific heat capacity and thermal conductivity of the freezing liquid in the low-temperature state are effectively improved, and the cold storage capacity and heat exchange capacity of the freezing liquid in the low-temperature state are effectively enhanced; the low-temperature stability of the freezing liquid system can be improved; 95 ethanol is used as the main component, which greatly reduces the cost in the production and processing process; the added components are all food grade, which is green and safe for the environment; at the same time, the salt component content of the freezing liquid is low, which significantly reduces the corrosion of the salt component to metal equipment.

[0062] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A food-grade freezing liquid for immersion quick freezing, characterized in that: It includes the following components: 95 ethanol, propylene glycol, betaine, calcium chloride, and purified water; The mass percentage of each component is: 95 ethanol 20%-30%, propylene glycol 10%-15%, betaine 5%-10%, calcium chloride 0%-0.5%, and the balance is pure water.

2. The food-grade freezing liquid for immersion quick freezing according to claim 1, characterized in that: The working temperature of the freezing liquid is -32°C to -34°C, and its components are as follows by mass percentage: 95 ethanol 20%, propylene glycol 10% to 15%, betaine 5%, calcium chloride 0.5%, and the balance is pure water.

3. The food-grade freezing liquid for immersion quick freezing according to claim 1, characterized in that: The working temperature of the freezing liquid is -35°C to -41°C, and its components are as follows by mass percentage: 95 ethanol 20%, propylene glycol 10% to 15%, betaine 10%, calcium chloride 0.5%, and the balance is pure water.

4. The food-grade freezing liquid for immersion quick freezing according to claim 1, characterized in that: The working temperature of the freezing liquid is -39°C to -41°C, and its components are as follows by mass percentage: 95 ethanol 20% to 30%, propylene glycol 15%, betaine 5% to 10%, and the balance is pure water.

5. The food-grade freezing liquid for immersion quick freezing according to any one of claims 1 to 4, characterized in that: The pure water is distilled water or deionized water.

Images