Freeze-dried powder for ice glaze preparation, ice glaze preparation and use method of ice glaze preparation

Abstract

The invention discloses freeze-dried powder for an ice glaze preparation, the ice glaze preparation and a use method of the ice glaze preparation. The preparation method of the freeze-dried powder for the ice glaze preparation comprises the following steps: step 1, collecting snakehead mucus; and step 2, removing impurities from the collected snakehead mucus, carrying out micron filtration on the impurity-removed liquid to obtain a filtrate, and carrying out freeze-drying operation on the filtrate to obtain freeze-dried powder. And dispersing the obtained freeze-dried powder in deionized water, centrifuging, taking the supernatant, and cooling to obtain the ice-coated preparation, the mass percentage of the freeze-dried powder in the ice-coated preparation being 0.2-2.5 wt%. The ice glaze preparation prepared from the freeze-dried powder is low in water activity, can reduce the water vapor partial pressure of the inner layer and the surface layer of fish, reduces the pressure difference between the water vapor on the surface layer of the fish and the water vapor in air in a freezing chamber, and inhibits ice crystal sublimation; the ice glaze preparation can inhibit the growth of ice crystals, improve the swelling phenomenon of the ice glaze, and prevent the ice glaze from releasing more expansion pressure when the ice glaze is frozen.

Description

Technical Field

[0001] The present invention relates to a general method for preserving meat, sausage, fish or fish products, and in particular to an ice coating, a preparation method and a use method. Background Art

[0002] Fish has always been popular among consumers due to its high nutritional value and delicate taste. However, due to its high water content and rich nutrients, it is easily affected by microorganisms and endogenous enzymes during storage and transportation, resulting in rapid quality decline and a short shelf life. The existing methods of fish preservation mainly include low-temperature preservation, controlled atmosphere preservation, radiation preservation, chemical preservation, biological preservation, etc. Frozen preservation is a type of low-temperature preservation, which is the most commonly used and lowest-cost preservation method.

[0003] Ice coating technology has been widely used to prevent oxidation and deterioration of fish during frozen storage. The ice layer acts as a barrier to control the transfer of water and oxygen permeation of frozen food. Pure water glaze has limited mechanical properties and will cause the glaze to break when hit. Frozen food with pure water glaze will cause adverse phenomena such as drying and oxidation, resulting in a poor taste. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a lyophilized powder for ice coat preparation, an ice coat preparation and a method for using the ice coat preparation, and the technical solution adopted includes:

[0005] A freeze-dried powder for ice coat preparation is prepared by the following method:

[0006] Step 1, collect black fish mucus;

[0007] Step 2: remove impurities from the collected black fish mucus, perform micron filtration on the liquid after the impurities are removed to obtain a filtrate, and perform freeze-drying operation on the filtrate to obtain a freeze-dried powder.

[0008] An embodiment of the present invention adopts a technical solution to solve the technical problem. The method for collecting snakehead fish mucus in step 1 comprises: taking a healthy and undamaged snakehead fish after resting, washing the fish skin with distilled water until the fish surface is clean, scraping and collecting the clean and transparent mucus on the fish skin with a scraper or a brush to obtain the snakehead fish mucus;

[0009] Or the method for collecting the snakehead mucus in step 1 industrially comprises: taking healthy and undamaged snakeheads after resting, washing the snakeheads with tap water until the debris on the surface of the snakeheads is washed away, sending the washed snakeheads into a brush roller type cleaning machine, repeating the operation of spraying water and rolling brushing for 1 minute for 3 times, wherein the intensity and time of rolling brushing are appropriate so that the surface of the snakeheads does not bleed and the body surface becomes rough and not sticky, collecting the coarse mucus at the bottom of the cleaning machine and adding crushed ice for cooling;

[0010] An embodiment of the present invention solves the technical problem by adopting a technical solution: the method for removing impurities from the collected black fish mucus in step 2 comprises:

[0011] The collected snakehead mucus is centrifuged, the supernatant is taken, and the filtrate is taken after filtering with a submicron filter;

[0012] Or the method for removing impurities from the collected black fish mucus in industry includes: filtering and removing impurities from the collected black fish mucus by a plate and frame filter press, filtering by a submicron filter and rotary membrane ultrafiltration, and then freezing and vacuum drying to obtain freeze-dried powder.

[0013] The technical solution adopted by an embodiment of the present invention to solve the technical problem is: the collected black fish mucus is centrifuged at 4000×g for 10 minutes.

[0014] A technical solution adopted by an embodiment of the present invention to solve its technical problem is: the filtering accuracy of the submicron filter is 0.22μm.

[0015] A technical solution adopted by an embodiment of the present invention to solve its technical problem is: the freeze-drying operation in step 2 includes: placing the filtrate in an environment of -20°C for freezing.

[0016] The present application also proposes an ice coat preparation, wherein the above-mentioned lyophilized powder is dispersed in deionized water, centrifuged, the supernatant liquid is taken, and cooled to obtain the ice coat preparation, wherein the mass percentage of the lyophilized powder in the ice coat preparation is 0.2wt% to 2.5wt%.

[0017] The technical solution adopted by an embodiment of the present invention to solve the technical problem is: the freeze-dried powder is dispersed in deionized water, heated to 40° C., and stirred and dispersed at a speed of 900 rpm for 1 hour.

[0018] The technical solution adopted by an embodiment of the present invention to solve the technical problem is: centrifuging at a speed of 6000 rpm in a centrifuge for 5 minutes and then taking the supernatant liquid.

[0019] A method for using the above-mentioned ice coating preparation is to cool the ice coating soaking liquid to 0-4°C, immerse the food to be frozen in the ice coating soaking liquid for 3-5 seconds to form a film on its surface, take out the food to be frozen and put it into an environment of -18°C to -25°C for freezing.

[0020] Beneficial effects of the present invention:

[0021] (1) The present application utilizes the byproduct of snakehead mucus, which has a wide source of raw materials, is inexpensive, and is easy to operate, and the resulting product is completely edible;

[0022] (2) The ice glaze preparation made from the above-mentioned freeze-dried powder has a low water activity, which can reduce the water vapor partial pressure in the inner and surface layers of the fish meat, reduce the water vapor pressure difference between the water vapor on the surface of the fish meat and the water vapor pressure in the air in the freezing room, inhibit the sublimation of ice crystals, thereby reducing the thickness of the ice glaze during frozen storage, and enhancing the oxygen barrier function of the ice glaze, thereby reducing the degree of oxidation of the frozen fish meat.

[0023] (3) Ice glaze preparations can inhibit the growth of ice crystals, improve the bulging phenomenon of ice glaze, prevent the ice glaze from releasing more expansion pressure when freezing and causing the ice glaze to rupture, enhance the ice glaze's ability to block oxygen, and thus reduce the degree of oxidation of frozen fish. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0025] Figure 1 This is an ice crystal diagram of an ice coat preparation having a freeze-dried powder content of 0.5 wt% after freezing;

[0026] Figure 2 This is an ice crystal diagram of an ice coat preparation having a freeze-dried powder content of 1.0 wt% after freezing;

[0027] Figure 3 This is an ice crystal diagram of an ice coat preparation having a freeze-dried powder content of 1.5 wt% after freezing;

[0028] Figure 4 This is an ice crystal diagram of an ice coat preparation having a freeze-dried powder content of 2.0 wt% after freezing;

[0029] Figure 5 This is a picture of ice crystals after freezing of an ice coating preparation having a freeze-dried powder content of 2.5 wt%.

[0030] Figure 6 The calculation results of the average ice crystal size of ice coating preparations with freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt% and 2.5wt%.

[0031] Figure 7 The mechanical properties after freezing of ice coating preparations with pure water and freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt% and 2.5wt%.

[0032] Figure 8 The ice crystal sublimation rates of ice coat preparations with pure water and freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt% and 2.5wt%.

[0033] Fig. 9The oxygen barrier properties of ice crystals of ice coat preparations with pure water and freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt% and 2.5wt%. DETAILED DESCRIPTION

[0034] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0035] The present invention provides a freeze-dried powder for ice coat preparation prepared by the following method:

[0036] Step 1, collect black fish mucus;

[0037] Step 2, removing impurities from the collected snakehead mucus, performing micron filtration on the liquid after the impurities removal to obtain a filtrate, and freeze-drying the filtrate to obtain a freeze-dried powder;

[0038] The method for collecting mucus on the surface of snakehead in the laboratory can be as follows: take a healthy and undamaged snakehead after resting, rinse the fish skin with distilled water, and gently scrape the clean and transparent mucus on the fish skin with a scraper or a slightly hard brush; centrifuge the collected mucus at 4000×g for 10 minutes, collect the supernatant, and filter it at 0.22 microns. Freeze the filtrate at -20℃, and vacuum dry it to obtain freeze-dried powder. The obtained freeze-dried powder can be stored in a centrifuge tube and sealed at -40C.

[0039] The method for collecting mucus on the surface of snakehead fish in industry can be adopted as follows: take healthy and undamaged snakehead fish after resting, rinse the snakehead fish with tap water until the debris on the surface of the snakehead fish is washed away, send the rinsed snakehead fish into a brush roller cleaning machine, repeat the operation of spraying water and rolling brushing for 1 minute for 3 times, the intensity and time of rolling brushing are suitable when the surface of the snakehead fish does not bleed, the body surface becomes rough and not sticky, collect the coarse mucus at the bottom of the cleaning machine and add crushed ice for cooling; the collected coarse mucus is first filtered and removed by a plate and frame filter press with a filtration mesh of 200 meshes, and then finely filtered by 0.22 micron microfiltration, in order to remove excess water and reduce the freeze-drying load, filter by a 1000Da rotary membrane ultrafiltration device, freeze at -20°C after collection, and obtain freeze-dried powder after vacuum drying.

[0040] Take 0.5g of freeze-dried powder and disperse it in 99.5g of deionized water; take 1.0g of freeze-dried powder and disperse it in 99g of deionized water; take 1.5g of freeze-dried powder and disperse it in 98.5g of deionized water; take 2.0g of freeze-dried powder and disperse it in 98g of deionized water; take 2.5g of freeze-dried powder and disperse it in 97.5g of deionized water, heat the above dispersion to 40°C and stir and disperse at a speed of 900rpm for 1h, then centrifuge at a speed of 6000rpm in a centrifuge for 5min, take the supernatant liquid, and cool it to obtain 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, and 2.5wt% ice coating preparations.

[0041] After the prepared glaze preparation is cooled, when it is needed, the glaze preparation is placed in a refrigerator to cool to 4°C, the food to be frozen is immersed in the glaze soaking liquid for 3 to 5 seconds to form a film on its surface, and the food to be frozen is taken out and placed in an environment of -18°C to -25°C for freezing.

[0042] The ice coating preparation in the present application was subjected to water activity determination, ice crystal observation, mechanical property test, black fish mucus ice sublimation test and oxygen permeability test.

[0043] (1) Water activity determination

[0044] In the supercooled region of the glaze preparation, the water activity of the glaze preparation is calculated by calculating the water activity of ice and supercooled water at the melting temperature (T m ) is estimated to be roughly the value at -20℃.

[0045] The water activity calculation formula is as follows:

[0046] a w =P / P0 Formula (1);

[0047] Where P is T m The vapor pressure of ice at T (mmHg), P0 is m Vapor pressure of supercooled water at (mmHg).

[0048] The test results of the water activity of the ice coating preparations with 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt% and 2.5wt% are shown in Table 1.

[0049] Table 1

[0050]

[0051]

[0052] According to the test results in Table 1, as the concentration of the freeze-dried powder in the ice coat preparation increases, the test value of the water activity gradually decreases.

[0053] (2) Ice crystals

[0054] The ice coating preparation was placed in a refrigerator and cooled to 4°C. When the temperature reached the set value, 30 μL of the sample was placed between the slide and the cover glass. The prepared slide was then placed on a cold stage at 4°C for 2 minutes. The temperature of the cold stage was then lowered from 4°C to -20°C at a cooling rate of 20°C / min. The microscope magnification was then adjusted to 50. The size and distribution of ice crystals were observed and photographed. The ice crystal images of the ice coating preparations with freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, and 2.5wt% after freezing were shown in the figure below. Figure 1-5 shown.

[0055] The obtained images were imported into Image-Pro Plus 6.0 software, and then the software was used to automatically identify the boundary contours of ice crystals and calculate the area of ​​each ice crystal. The number of ice crystals calculated was at least 200. Subsequently, all area data were transferred to Excel, and the single crystal diameter was calculated using formula (2), and the average diameter of ice crystals was calculated using formula (3). The ice crystal size ratio was calculated using the formula.

[0056]

[0057]

[0058] Among them, d i is the diameter of the ith ice crystal, A i is the area of ​​the ith ice crystal, is the average diameter of ice crystals.

[0059] The calculated results of the average ice crystal size of the ice coat preparations with freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, and 2.5wt% are as follows: Figure 6 As shown. Figure 6 The measurement results show that as the concentration of freeze-dried powder, i.e., black fish mucus, in the ice coating preparation increases, the average diameter of ice crystals gradually decreases.

[0060] (3) Mechanical properties test

[0061] First, pure water, 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt% of the glaze preparation were added to a cylindrical silica gel mold with an inner diameter of 10mm and a height of 1.5cm, respectively, and then frozen at -20℃ for 5 hours to form cylindrical ice. The bottom diameter of the obtained ice column was 10mm and the height was 2mm. The compressive strength of the ice was measured using a texture analyzer.

[0062] The test method is: before the test, immerse the test platform and the probe in liquid nitrogen for 1 minute to ensure that they are in a suitable low temperature state. Then place the ice column on the test platform so that one side is in contact with the platform surface. Finally, use a P / 100 probe to test at a speed of 1mm / s, set the trigger force to 1N, and set the compression distance to 5mm. Record the maximum force required to break the ice, which is the compressive strength value of the ice.

[0063] The test results of the compressive strength values ​​of ice in ice coating preparations with pure water and freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, and 2.5wt% are as follows: Figure 7 As shown, according to Figure 7 When the test results were shown, the compressive strength values ​​of ice in the ice coat preparations were higher than that of ice in pure water, and within the range of 0.5wt% to 2.0wt% of the freeze-dried powder content, the compressive strength values ​​of ice in the ice coat preparations gradually increased with the increase of the freeze-dried powder content.

[0064] (4) Mechanical properties test

[0065] Snakehead slime ice sublimation test: First, pour the ice coating preparation and pure water into a cylindrical silicone mold with an inner diameter of 5 cm and a height of 3 cm. Then, place the mold in a refrigerator at -20°C and freeze for 12 hours. After freezing, take out the ice and the mold together and weigh them, and record their weight as m0, which is the weight of ice on day 0. Next, record the weight of ice m1 on days 30, 60, 90, 120, 150, and 180 respectively.

[0066] The formula for calculating the ice sublimation rate is shown in equation (4).

[0067]

[0068] The sublimation rate of ice crystals of ice coating preparations with pure water and freeze-dried powder content of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt% and 2.5wt% is as follows: Figure 8 As shown, according to Figure 8 The test results show that the ice crystal sublimation rate of the ice coat preparation made from black fish mucus is lower than that of pure water. As the content of freeze-dried powder increases, the ice crystal sublimation rate of the ice coat gradually decreases.

[0069] (5) Oxygen permeability test

[0070] First, add 25 ml of a vitamin C solution with a concentration of 5 mg / ml into the permeable cup. Next, use the ice formed by the ice coating preparation to seal the permeable cup, and cover the control cup with ice formed by pure water. The permeable cup was then placed at a temperature of -20°C and a relative humidity of 75% for 7 days. After 7 days, the sample was taken out and then thawed at 4°C for 5 hours. After thawing, the absorbance of the Vc solution was measured at a wavelength of 244nm using a UV-visible spectrophotometer. The vitamin C retention rate was calculated by the ratio of the final measured vitamin C content to the initial vitamin C content. The vitamin C retention rates of ice formed by the ice coating preparation and ice formed by pure water are shown in Fig. 9 As shown. The Vc retention rate can reflect the oxygen permeability of ice.

[0071] The vitamin C retention rate of ice in ice coat preparations with freeze-dried powder contents of 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt% and 2.5wt% is higher than that of pure water. As the content of freeze-dried powder increases, the vitamin C retention rate of ice coat gradually increases, that is, as the content of freeze-dried powder increases, the oxygen barrier property of ice coat gradually increases.

[0072] Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A freeze-dried powder for ice coating preparation, characterized in that: Prepared by the following method: Step 1, collect black fish mucus; Step 2: remove impurities from the collected black fish mucus, perform micron filtration on the liquid after the impurities are removed to obtain a filtrate, and perform freeze-drying operation on the filtrate to obtain a freeze-dried powder.

2. The freeze-dried powder for ice coat preparation according to claim 1, characterized in that The method for collecting snakehead mucus in step 1 comprises: taking a healthy and undamaged snakehead after resting, washing the fish skin with distilled water until the fish surface is clean, scraping and collecting the clean and transparent mucus on the fish skin with a scraper or a brush, and obtaining the snakehead mucus; Or the industrial method for collecting the snakehead mucus in step 1 comprises: taking a healthy and undamaged snakehead after resting, washing the snakehead with tap water until the debris on the surface of the snakehead is washed away, sending the washed snakehead into a brush roller cleaning machine, repeating the operation of spraying water and rolling brushing for 3 times and resting for 1 minute, the intensity and time of rolling brushing being appropriate so that the surface of the snakehead does not bleed and the body surface becomes rough and non-sticky, collecting the coarse mucus at the bottom of the cleaning machine and adding crushed ice for cooling.

3. The freeze-dried powder for ice coat preparation according to claim 2, characterized in that The method for removing impurities from the collected snakehead mucus in step 2 comprises: centrifuging the collected snakehead mucus, taking the supernatant, filtering it with a submicron filter, and then taking the filtrate; or the method for removing impurities from the collected snakehead mucus in industry comprises: first filtering and removing impurities from the collected snakehead mucus with a plate and frame filter press, then filtering with a submicron filter and rotary membrane ultrafiltration, and then freezing and vacuum drying to obtain freeze-dried powder.

4. The freeze-dried powder for ice coat preparation according to claim 3, characterized in that The collected snakehead mucus was centrifuged at 4000×g for 10 min.

5. The freeze-dried powder for ice coat preparation according to claim 3, characterized in that The filtration accuracy of the submicron filter is 0.22μm.

6. The freeze-dried powder for ice coat preparation according to claim 1, characterized in that The freeze-drying operation in step 2 includes: freezing the filtrate in an environment of -20°C.

7. An ice coating preparation, characterized in that: The lyophilized powder according to any one of claims 1 to 6 is dispersed in deionized water, centrifuged, the supernatant liquid is collected, and cooled to obtain an ice coat preparation, wherein the mass percentage of the lyophilized powder in the ice coat preparation is 0.2 wt % to 2.5 wt %.

8. The ice coating preparation according to claim 7, characterized in that: The freeze-dried powder was dispersed in deionized water, heated to 40°C and stirred at 900 rpm for 1 h.

9. The ice coating preparation according to claim 7, characterized in that: After centrifugation at 6000 rpm for 5 min, the supernatant was collected.

10. A method for using the ice coating preparation according to any one of claims 7 to 9, characterized in that: The glaze soaking liquid is cooled to 0-4°C, the food to be frozen is immersed in the glaze soaking liquid for 3-5s to form a film on the surface, and the food to be frozen is taken out and placed in an environment of -18°C to -25°C for freezing.

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