Alcohol-free green food-grade secondary refrigerant, preparation method, application and method for freezing food

Abstract

The invention discloses an alcohol-free green food-grade secondary refrigerant, a preparation method, application and a food freezing method, and relates to the technical field of food freezing. The alcohol-free green food-grade secondary refrigerant is prepared from the following components in percentage by mass: 35 percent to 45 percent of calcium chloride, 10 percent to 25 percent of trehalose, 5 percent to 15 percent of glucose, 1 percent to 3 percent of vitamin C, 0.01 percent to 0.03 percent of epsilon-polylysine, 0.02 percent to 0.05 percent of tea polyphenol, 0.01 percent to 0.03 percent of phytic acid and the balance of water. The refrigerating medium is creatively composed of food-grade components, does not contain organic components such as alcohols, and can be in direct contact with fruit and vegetable raw materials for direct immersion freezing. The fruits and vegetables are in direct contact with the secondary refrigerant, so that the fruits and vegetables can be quickly cooled to pass through a maximum ice crystal generation zone (-1 to-5 DEG C), the damage of ice crystals to cell tissues is reduced, the flavor and nutrient substances of the fruits and vegetables are preserved, and the quality of subsequent fruit and vegetable processed products is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of food freezing, and in particular to an alcohol-free, green, food-grade refrigerant, a preparation method, an application thereof, and a method for freezing food. Background Art

[0002] Freezing is an important pre-processing method for food processing, effectively extending the processing cycle. Immersion freezing uses a low-temperature liquid refrigerant as a medium. Leveraging the rapid heat transfer rate of liquids, it rapidly freezes the immersed material, forming fine, uniform ice crystals that minimize damage to the food's cellular structure. The texture, flavor, and nutritional quality of the thawed material are significantly superior to those of traditional air freezing.

[0003] Currently, refrigerants commonly used in immersion freezing all contain organic alcoholic components such as ethanol and propylene glycol. These alcohols have low freezing points and are suitable for low-temperature environments, so refrigerants all contain varying degrees of alcohol. For example, Patent Publication No. CN102241964B discloses a quaternary refrigerant for food immersion freezing, consisting of ethanol, sodium chloride, water-soluble protein, and water. Patent Application No. CN201410141381.5 discloses a refrigerant for food immersion freezing, consisting of F42 fructose syrup, ethanol, sodium chloride, hydrolyzed gelatin, and water. Patent Publication No. CN201210558113.4 discloses a ternary refrigerant for food immersion freezing, consisting of ethanol, propylene glycol, and water. The refrigerant components, by mass percentage, are: 15%-20% ethanol, 25%-30% propylene glycol, and the remainder water. Alcohol-based refrigerants are flammable and volatile, have poor stability, and cannot come into direct contact with food ingredients. Furthermore, because refrigerants generally contain alcohol, when the operating temperature is below -30°C, the alcohol content exceeds 37%, making direct immersion freezing impossible. In practice, the raw materials must be pre-packaged before being immersed in the refrigerant, a process known as indirect immersion freezing. This method cannot be effectively integrated with subsequent processing, making the practical application of immersion freezing technology difficult in food processing. Further processing of the frozen materials requires re-opening the packaging, which is cumbersome, impractical, and costly.

[0004] Therefore, providing a green food-grade refrigerant that can directly freeze to solve the problem that the freezing point of the alcohol-free green refrigerant is too high and cannot effectively quick-freeze the material is a technical problem that the present invention urgently needs to solve. Summary of the Invention

[0005] The present invention provides an alcohol-free, green, food-grade refrigerant, a preparation method, an application, and a method for freezing food, aiming to solve the problems existing in the above-mentioned background technology.

[0006] In order to achieve the above technical objectives, the present invention mainly adopts the following technical solutions: The first aspect of the present application discloses a kind of alcohol-free green food-grade refrigerant, including the following components by mass percentage: calcium chloride 35%-45%, trehalose 10%-25%, glucose 5%-15%, vitamin C 1%-3%, epsilon-polylysine 0.01%-0.03%, tea polyphenol 0.02%-0.05%, phytic acid 0.01%-0.03%, and the rest is water.

[0007] The second aspect of the present application discloses a kind of alcohol-free green food-grade refrigerant of the preparation method of the first aspect, comprising: calcium chloride, trehalose, glucose, vitamin C, epsilon-polylysine, tea polyphenol, phytic acid and water are mixed uniformly, i.e. the alcohol-free green food-grade refrigerant is obtained.

[0008] The third aspect of the present application discloses a kind of alcohol-free green food-grade refrigerant of the first aspect in-35 ℃~-45 ℃ Condition frozen food application.

[0009] In the preferred embodiment of the present application, the food is selected from any one of fruits and vegetables, livestock and poultry meat, fish and shrimp.

[0010] The fourth aspect of the present application discloses a kind of frozen food method, using the alcohol-free green food-grade refrigerant of the first aspect to freeze, comprising the following steps: (1) the food to be frozen is cut into pieces, and pre-cooled; (2) the pre-cooled food is placed in the alcohol-free green food-grade refrigerant and frozen; (3) after the center temperature of the food reaches-3 ℃~-8 ℃, it is transferred to a frozen environment for storage.

[0011] In the preferred embodiment of the present application, in step (1), the length and width of the cut food are not more than 3 cm.

[0012] In the preferred embodiment of the present application, in step (1), the pre-cooling condition is pre-cooled at 4 ℃; in step (3), the frozen environment temperature is-18 ℃.

[0013] In the preferred embodiment of the present application, in step (2), the temperature of the refrigerant is-35 ℃~-45 ℃.

[0014] In the preferred embodiment of the present application, it further includes a thawing step: the frozen and thawed food is taken out, and sequentially passes through-18 ℃→4 ℃→room temperature for gradient thawing.

[0015] Compared with the prior art, the present application has the following beneficial effects: The present application creatively composes the coolant with food-grade ingredients, which does not contain organic ingredients such as alcohol and can directly contact with fruit and vegetable raw materials for direct immersion freezing. Direct contact of fruits and vegetables with the coolant of the present application can rapidly cool the fruits and vegetables to pass through the maximum ice crystal generation zone (-1~ -5℃), reduce the damage of ice crystals to cell tissues, preserve the flavor and nutrients of fruits and vegetables, and improve the quality of subsequent fruit and vegetable processing products. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Freezing point range determination curve of the alcohol-free green food-grade coolant prepared in Example 1 of the present application; Figure 2 Comparison chart of freezing curves of carrots immersed with the coolant (ICF) provided in Example 1 of the present application and carrots not immersed with the coolant (AF). DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0018] The present application is to solve the problem that the freezing point of alcohol-free green coolant is too high and cannot effectively quick-freeze materials. A kind of alcohol-free green coolant is invented by the combination of calcium chloride, trehalose, glucose, vitamin C, ε-polylysine, tea polyphenol and phytic acid, which can be used at a working temperature of -35℃ to -50℃. Calcium chloride can lower the freezing temperature of the solution and provide calcium ions to the solution. Calcium salt is a green and environmentally friendly preservative, which can maintain the stability of cell structure, reduce the permeability of cell wall and maintain the hardness of fruits and vegetables; trehalose as a cryoprotective agent can maintain the stability of biological membranes, proteins and other tissues under extreme environments such as high temperature, low temperature and drought stress. Vitamin C and glucose can delay browning of fruits and vegetables and improve color stability. ε-polylysine is a natural preservative, and tea polyphenol and phytic acid are natural antioxidants, which are beneficial to the storage of fruits and vegetables.

[0019] The following will be described by specific examples.

[0020] Example 1 Preparation of alcohol-free green food-grade coolant The mass percentage content of each component of the coolant is as follows: calcium chloride 35%, trehalose 20%, glucose 5%, vitamin C 1%, ε-polylysine 0.02%, tea polyphenol 0.03%, phytic acid 0.02%, and the solvent is water.

[0021] The calcium chloride, trehalose, glucose, vitamin C, epsilon-polylysine, tea polyphenol, phytic acid and water are mixed uniformly to obtain the non-alcohol green food-grade secondary refrigerant.

[0022] The prepared secondary refrigerant is subjected to freezing test, wherein the freezing point range determination method is as follows: The prepared secondary refrigerant is subjected to freezing test, wherein the freezing point range determination method is as follows: Figure 1

[0023] As shown in Figure 1 , the secondary refrigerant has a flat curve in the cooling process. The temperature on the flat curve can be regarded as the freezing point range of the secondary refrigerant. The freezing point range of the secondary refrigerant is -35℃ to -36.5℃.

[0024] Preparation of non-alcohol green food-grade secondary refrigerant The mass percentage of each component of the secondary refrigerant is as follows: calcium chloride 40%, trehalose 15%, glucose 5%, vitamin C 1%, epsilon-polylysine 0.02%, tea polyphenol 0.03%, phytic acid 0.02%, and water as the solvent.

[0025] The calcium chloride, trehalose, glucose, vitamin C, epsilon-polylysine, tea polyphenol, phytic acid and water are mixed uniformly to obtain the non-alcohol green food-grade secondary refrigerant.

[0026] The prepared secondary refrigerant is subjected to freezing test, wherein the freezing point range determination method is as follows:

[0027] The freezing point range of the secondary refrigerant is -40℃ to -42℃.

[0028] Application example The secondary refrigerant prepared in Example 1 or 2 is applied to the freezing of carrots, and the method is as follows: Step A: carrots are selected as raw materials, washed and peeled, and cut into blocks with a thickness of 2 cm and placed in 4℃ for precooling; Step B: the pre-cooled material is directly placed in the secondary refrigerant prepared in Example 1 or 2; Step C: when the center temperature of the carrot block reaches -5℃, it is transferred to -18℃ for storage.

[0029] Test example: quality of carrots after freezing and thawing ​The carrot frozen by the coolant (ICF) prepared in Example 1 was compared with the carrot frozen by the coolant (AF) at -35℃ to -36.5℃, and the frozen-thawed carrot pieces were taken out and subjected to gradient thawing at -18℃→4℃→room temperature, respectively, the cooling time (4℃ to -5℃) was monitored, and the juice loss rate and the hardness were detected, which are important indexes for evaluating the food freezing effect. The results are shown in Table 1 and Figure 2

[0030] Table 1 As shown in Table 1 and Figure 2 Table 2, the cooling time of the carrot pieces in the coolant of the present application was significantly lower than that of the carrot pieces without the coolant, and the hardness was high and the juice loss rate was low. The reason is that the material rapidly passed through the maximum ice crystal generation zone (-1 to -5℃), and the generated ice crystals had little effect on the organization, so the juice loss rate was low and the hardness was high.

[0031] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0032] Although the embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, alternatives, and variations can be made thereto without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.​

Claims

1. An alcohol-free green food-grade coolant, characterized in that: Calculated by mass percentage, it includes the following components: calcium chloride 35% to 45%, trehalose 10% to 25%, glucose 5% to 15%, vitamin C 1% to 3%, ε-polylysine 0.01% to 0.03%, tea polyphenols 0.02% to 0.05%, phytic acid 0.01% to 0.03%, and the rest is water.

2. The method for preparing the alcohol-free green food-grade coolant according to claim 1, wherein: include: Calcium chloride, trehalose, glucose, vitamin C, ε-polylysine, tea polyphenols, phytic acid and water are uniformly mixed to obtain the alcohol-free green food-grade cooling agent.

3. Use of the alcohol-free green food-grade refrigerant as claimed in claim 1 in freezing food at -35°C to -45°C.

4. The use according to claim 3, characterized in that The food is selected from any one of fruits and vegetables, livestock and poultry meat, fish, and shrimp.

5. A method for freezing food, characterized in that: Utilizing the alcohol-free green food-grade coolant of claim 1 for freezing comprises the following steps: (1) Cut the food to be frozen into pieces and pre-cool it; (2) placing the pre-cooled food into the alcohol-free green food-grade coolant for freezing; (3) After the center temperature of the food reaches -3°C to -8°C, transfer it to a frozen environment for storage.

6. The method for freezing food according to claim 5, characterized in that: In step (1), the length and width of the food after cutting shall not exceed 3 cm.

7. The method for freezing food according to claim 5, characterized in that: In step (1), the pre-cooling condition is: pre-cooling at 4°C; in step (3), the freezing environment temperature is -18°C.

8. The method for freezing food according to claim 5, characterized in that: In step (2), the temperature of the coolant is -35°C to -45°C.

9. The method for freezing food according to claim 5, characterized in that: The thawing step is also included: the frozen and thawed food is taken out and thawed in a gradient manner through -18°C → 4°C → room temperature.

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