A method for prolonging supercooling of meat products in a magnetic field environment

Abstract

The invention discloses a method for prolonging supercooling of meat products in a magnetic field environment, and belongs to the field of fresh-keeping technology. The method of the invention uses magnetic fields of different magnetic field strengths to process meat products in stages, uses magnetic field-assisted micro-freezing technology, and uses low-temperature treatment (1 to 2°C below the freezing point) to freeze part of the water in the food, thereby prolonging the time that pork is maintained in a supercooled state, significantly prolonging the storage period, improving water retention, reducing juice loss, and improving the storage quality of meat products.

Description

Technical Field

[0001] The invention relates to a method for prolonging supercooling of meat products in a magnetic field environment, belonging to the technical field of fresh-keeping. Background Art

[0002] Freezing is one of the main ways to preserve meat. Freezing meat can reduce the growth rate of microorganisms and the oxidation of proteins and fats. Conventional freezing methods will cause the loss of juice, nutrient loss, structural collapse and poor taste of meat after thawing due to the growth of ice crystal size during freezing and storage.

[0003] In order to extend the shelf life of food, it is often necessary to regulate the storage environment, inhibit the growth and reproduction of microorganisms, and reduce the activity of endogenous enzymes to inhibit the physiological activities or biochemical reactions of food. The corresponding technical methods can be divided into three categories: physical methods, chemical methods, and biological methods. Among them, physical methods inhibit or kill harmful microorganisms, reduce oxidation, and destroy enzyme activity by changing external factors such as temperature, pressure, and oxygen content. The combination of low-temperature technology and physical methods can improve the quality of food storage, extend the storage period, and improve economic benefits. In recent years, in addition to traditional physical methods such as ultraviolet sterilization, ultrasound, and irradiation, new physical preservation technologies have also been continuously developed, including ice temperature, electromagnetic treatment, high-voltage electrostatic field, ultra-high voltage, and modified atmosphere packaging. Among them, magnetic field technology has attracted widespread attention due to its outstanding advantages such as good biocompatibility, mild action, environmental protection, and energy saving.

[0004] The research and application of new magnetic field combined with freezing technology can improve the quality of frozen meat. Summary of the invention

[0005] In order to solve at least one of the above problems, the present invention provides a method for prolonging the supercooling of meat products in a magnetic field environment. The method uses magnetic fields of different magnetic field strengths to process meat products in stages, thereby prolonging the time that pork is maintained in a supercooled state and can significantly extend the storage period, thereby improving water retention, reducing juice loss, and improving the storage quality of meat products.

[0006] The main purpose of the present invention is to provide a method for prolonging the supercooling of meat products in a magnetic field environment, the method comprising: storing the meat products in a static magnetic field environment at a temperature of -5 to -1°C for 8 to 20 days; wherein the static magnetic field is processed in stages using different magnetic field intensities, first storing at 4 to 6 mT for 5 to 8 days, then storing at 8 to 10 mT for 2 to 5 days, and then storing at 4 to 6 mT for 5 to 8 days.

[0007] In one embodiment, the staged treatment is first storing at 4 mT for 8 days, then storing at 8 mT for 2 days, and then storing at 5 mT for 8 days.

[0008] In one embodiment, the method comprises the following steps:

[0009] (1) Pre-processing of fresh meat products;

[0010] (2) Place the meat product processed in step (1) on a tray and wrap it with plastic wrap;

[0011] (3) The tray of step (2) is placed in a static magnetic field environment for storage.

[0012] In one embodiment, the pretreatment in step (1) is to cut and trim the meat product. Optionally, in step (1), the meat product is cut into a suitable size and shape.

[0013] In one embodiment, the tray in step (2) is a plastic tray or a ceramic tray sterilized with 75% ethanol. Optionally, in step (2), the processed meat product is placed in the tray so that the meat is evenly distributed to avoid storage being affected by meat accumulation. Optionally, in step (2), the tray is sealed with plastic wrap to prevent a large amount of water loss from the meat product.

[0014] In one embodiment, the step (3) is to store the meat product in a freezer having a freezing function and a magnetic field generating function. Optionally, the freezer is a magnetic field freezer.

[0015] In one embodiment, the meat product includes pork, beef, chicken breast, salmon, tuna, etc.

[0016] Advantages and effects of the present invention:

[0017] The method of the present invention uses magnetic fields of different magnetic field strengths to process meat products in stages, and uses magnetic field-assisted micro-freezing technology. It is difficult for water molecules to be arranged in clusters, and freezing requires further reducing the entropy value of the system, that is, using low-temperature treatment (1-2°C below the freezing point) to freeze part of the water in the food, thereby extending the time that pork can be maintained in a supercooled state, significantly extending the storage period, improving water retention, reducing juice loss, and improving the storage quality of meat products. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : Freezing curve of Example 1.

[0019] Figure 2 : Water holding rate of Examples 1-3 and Comparative Examples 1-2.

[0020] Figure 3 : Color parameters of Examples 1-3 and Comparative Examples 1-2.

[0021] Figure 4 : The cooking loss rates of Examples 1-3 and Comparative Examples 1-2.

[0022] Figure 5 : Juice loss rate of Examples 1-3 and Comparative Examples 1-2.

[0023] Figure 6 : Volatile basic nitrogen of Examples 1-3 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0024] Experimental materials and instruments:

[0025] Pork: Select pork tenderloin from the same manufacturer and batch with no obvious fat and fascia on the surface (purchased from a large supermarket in Wuxi City). After purchase, quickly cut the pork into even pieces of 3.5 cm×3.5 cm×3.5 cm in a ventilated room temperature environment, put them into plastic trays, seal them with plastic wrap, weigh them, and place them in an ordinary refrigerator and a magnetic field freezer for freezing.

[0026] Refrigeration system and device: MFI-F1 magnetic field freezer, Indoster (Wuxi) Induction Technology Co., Ltd.; BCD-216SDC Haier refrigerator, Qingdao Haier Co., Ltd.

[0027] Detection method:

[0028] (1) Determination of pH value

[0029] Referring to GB5009.237-2016 "National Food Safety Standard for the Determination of pH Value of Food", 3 g of homogenized thawed pork samples were weighed into ziplock bags, 30 mL of 0.1 mol / L KCl solution was added, and after beating for 60 s, the mixture was poured into a 50 mL centrifuge tube and allowed to stand for 5 min, and the pH was directly measured using a pH meter. Four parallel experiments were performed for each group of samples.

[0030] (2) Determination of moisture content

[0031] Refer to the direct drying method in GB5009.3-2016 "National Food Safety Standard Determination of Water in Food", with slight modifications. Homogenize the thawed pork and take about 2 g (accurate to 0.0001g) of sample (M0) and evenly spread it in a constant weight aluminum box (M2), dry it in a 105°C oven for 24 hours until constant weight, take it out and cool it in a drying dish for 0.5 hours to room temperature, and weigh it immediately (M1). Each group of samples was tested in parallel 3 times. The moisture content (Watercontent, WC) is calculated as follows:

[0032]

[0033] Wherein, M0 and M1 are the mass (g) of the sample and the aluminum box before and after drying, respectively, and M2 is the mass (g) of the aluminum box at a constant weight.

[0034] (3) Determination of water holding capacity

[0035] The experiment measured the water holding capacity of thawed pork by removing free water through high-speed centrifugation. About 2 g of sample (M0) was weighed and placed in the center of a double-layer rapid qualitative filter paper in a 50 mL centrifuge tube, with sufficient absorbent cotton pads at the bottom. Centrifuge at 4000 rpm for 10 min at 4°C. After centrifugation, weigh immediately (M1), and each group of samples was tested in parallel 3 times. The water holding capacity (WHC) is calculated as follows:

[0036]

[0037] Where M0 and M1 are the masses (g) of pork and beef samples before and after centrifugation, respectively, and WC is the moisture content of the samples before centrifugation.

[0038] (4) Determination of color value

[0039] The experiment used a handheld colorimeter to measure the color value of the thawed pork sample. The test plane was directly placed on the sample surface after correction with a standard white plate. The L measured in the CIELAB color space defined by the International Electronic Laboratory Committee * 、a * and b * The value is used to characterize the sample color value, where L * Indicates brightness, a * and b * Indicates chromaticity. L * is brightness, a * is the color range from red to green, b * The color range is from yellow to blue. Three parallel experiments were performed for each group of samples. The △E value is the total color difference, and the calculation formula is as follows:

[0040]

[0041] Where, ΔL * , Δa * and Δb * Indicates the L measured in each freezing cycle * 、a * and b * The value is similar to that of the fresh sample L * 、a * and b * △E does not indicate the direction of color difference deviation. The larger the value, the greater the color difference from the standard sample.

[0042] (5) Determination of cooking loss rate

[0043] Take a 3.5 cm × 3.5 cm × 3.5 cm pork tenderloin, accurately weigh its mass (m1), put it into a ziplock bag, exhaust the air in the bag and place it in a 85℃ water bath. Take it out after 20 minutes, cool it to room temperature, gently dry the surface moisture with absorbent paper, weigh the sample mass (m2), and calculate the cooking loss rate according to the following formula:

[0044]

[0045] (6) Determination of juice loss rate

[0046] Weigh the samples before freezing (M0), and after thawing, gently absorb the surface moisture of the samples with absorbent paper until there is no obvious water sheen on the surface, and weigh them immediately (M1). Each group of samples was tested in parallel 3 times. The calculation formula for the juice loss rate (Driploss, DL) is as follows:

[0047]

[0048] Among them, M0 and M1 are the mass (g) of the sample before freezing and after thawing and water absorption, respectively.

[0049] (7) Determination of volatile basic nitrogen (TVB-N) content

[0050] Refer to the automatic Kjeldahl nitrogen analyzer method in GB5009.228-2016 "National Food Safety Standard Determination of Volatile Basic Nitrogen in Foods", with slight modifications. Weigh 10 g of homogenized thawed pork into a ziplock bag, add 75 mL of deionized water, beat for 60 s, add 1 g of magnesium oxide powder, mix well, and let stand for 30 min. After the sample is distilled according to the instrument setting parameters, it is titrated with 0.02 mol / L hydrochloric acid solution. Three parallel experiments were performed for each group of samples.

[0051] The technical solution, its implementation process and principle, etc. will be further explained in conjunction with several embodiments. However, it should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described in the following (embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here.

[0052] In the following examples, unless otherwise specified, the various raw materials, reagents, reaction equipment, testing equipment and methods used can be obtained through commercial purchase or other channels.

[0053] Embodiment 1:

[0054] The meat products are processed in stages using magnetic fields of different magnetic field strengths, and the micro-freezing technology is assisted to prolong the supercooling of the meat products. The specific method includes the following steps:

[0055] (1) Pre-processing fresh pork tenderloin; specifically, cutting the pork tenderloin into uniform pieces with a size of 3.5 cm × 3.5 cm × 3.5 cm;

[0056] (2) placing the meat product processed in step (1) in a plastic tray, distributing the meat evenly and avoiding accumulation, and wrapping it with plastic wrap; wherein the tray is disinfected with 75% ethanol;

[0057] (3) The tray of step (2) is placed in a static magnetic field environment at a temperature of -3°C for storage; the specific conditions are: first, storage at a magnetic field strength of 4 mT for 8 days, then storage at a magnetic field strength of 8 mT for 2 days, and then storage at a magnetic field strength of 5 mT for 8 days.

[0058] Determination of freezing curve: During the freezing process, a T-type thermocouple wire (1 mm in diameter) connected to a data logger was inserted into the geometric center of the pork sample to detect the temperature change at the center, and the data was recorded every 5 minutes. The results showed that no obvious phase change was found in the temperature curve, and the sample was still in an unfrozen state on the 18th day.

[0059] The pH values ​​of the samples were measured after different storage times. The results show that the pH value increased from two days to four days of storage, but decreased on the sixth day. This may be due to protein denaturation in pork or anaerobic metabolism of glycogenolysis, which produced lactic acid and caused the pH value to decrease. On the 12th day, the pH value increased again.

[0060] The water holding capacity of the samples after storage for different time periods was measured. It can be seen that the water holding capacity of pork tenderloin gradually decreased with the increase of storage time. Figure 2 The results showed that the water retention rate was about 78% after 18 days of storage.

[0061] The effect of static magnetic field on the color parameters of pork tenderloin, including L* (brightness value), a* (yellowness value), and b* (redness value), was measured. As the storage time increased, the a* value of pork decreased and the meat color gradually darkened, which may be due to the oxidation of myoglobin to brown metmyoglobin. The a* (yellowness value) and b* (redness value) after 18 days of storage were as follows: Figure 3 .

[0062] The effect of static magnetic field on cooking loss rate was determined. Figure 4 It showed that the cooking loss rate was 28.1% after 18 days of storage.

[0063] The effect of static magnetic field on the juice loss rate was determined, such as Figure 5 It shows that the juice loss rate after 18 days of storage is 5.64%.

[0064] The effect of static magnetic field on volatile basic nitrogen was determined, such as Figure 6It showed that the volatile basic nitrogen content was 10.46 mg / 100 g after 18 days of storage.

[0065] Embodiment 2:

[0066] The meat products are processed in stages using magnetic fields of different magnetic field strengths, and the micro-freezing technology is assisted to prolong the supercooling of the meat products. The specific method includes the following steps:

[0067] (1) Pre-processing fresh pork tenderloin; specifically, cutting the pork tenderloin into uniform pieces with a size of 3.5 cm × 3.5 cm × 3.5 cm;

[0068] (2) placing the meat product processed in step (1) in a plastic tray, distributing the meat evenly and avoiding accumulation, and wrapping it with plastic wrap; wherein the tray is disinfected with 75% ethanol;

[0069] (3) The tray of step (2) is placed in a static magnetic field environment at a temperature of -4°C for storage; the specific conditions are: first, storage at a magnetic field strength of 6 mT for 5 days, then storage at a magnetic field strength of 8 mT for 2 days, and then storage at a magnetic field strength of 5 mT for 8 days.

[0070] During the storage process, the freezing curve was measured. The results showed that no obvious phase change was found in the temperature curve, and the sample was still in an unfrozen state on the 15th day. Other results are as follows Figure 2-6 shown.

[0071] Embodiment 3:

[0072] The meat products are processed in stages using magnetic fields of different magnetic field strengths, and the micro-freezing technology is assisted to prolong the supercooling of the meat products. The specific method includes the following steps:

[0073] (1) Pre-processing fresh pork tenderloin; specifically, cutting the pork tenderloin into uniform pieces with a size of 3.5 cm × 3.5 cm × 3.5 cm;

[0074] (2) placing the meat product processed in step (1) in a plastic tray, distributing the meat evenly and avoiding accumulation, and wrapping it with plastic wrap; wherein the tray is disinfected with 75% ethanol;

[0075] (3) The tray of step (2) is placed in a static magnetic field environment at a temperature of -4°C for storage; the specific conditions are: first, storage at a magnetic field strength of 4 mT for 6 days, then storage at a magnetic field strength of 8 mT for 4 days, and then storage at a magnetic field strength of 4 mT for 8 days.

[0076] During the storage process, the freezing curve was measured. The results showed that no obvious phase change was found in the temperature curve, and the sample was still in an unfrozen state on the 18th day. Other results are as follows Figure 2-6 shown.

[0077] Comparative Example 1:

[0078] The magnetic field-assisted micro-freezing technology is used to prolong the supercooling of meat products. The specific method includes the following steps:

[0079] (1) Pre-processing fresh pork tenderloin; specifically, cutting the pork tenderloin into uniform pieces with a size of 3.5 cm × 3.5 cm × 3.5 cm;

[0080] (2) placing the meat product processed in step (1) in a plastic tray, distributing the meat evenly and avoiding accumulation, and wrapping it with plastic wrap; wherein the tray is disinfected with 75% ethanol;

[0081] (3) The tray of step (2) is placed in a static magnetic field environment with a temperature of -4°C and a magnetic field strength of 4 mT for 18 days.

[0082] During the storage process, the freezing curve was measured. The results showed that although no obvious phase change was found in the temperature curve, the sample temperature dropped to -3°C on the 12th day of storage, and the sample was found to be frozen when it was taken out on the 12th day. Other results are as follows Figure 2-6 shown.

[0083] Comparative Example 2:

[0084] The magnetic field-assisted micro-freezing technology is used to prolong the supercooling of meat products. The specific method includes the following steps:

[0085] (1) Pre-processing fresh pork tenderloin; specifically, cutting the pork tenderloin into uniform pieces with a size of 3.5 cm × 3.5 cm × 3.5 cm;

[0086] (2) placing the meat product processed in step (1) in a plastic tray, distributing the meat evenly and avoiding accumulation, and wrapping it with plastic wrap; wherein the tray is disinfected with 75% ethanol;

[0087] (3) The tray of step (2) is placed in a static magnetic field environment with a temperature of -4°C and a magnetic field strength of 7 mT for 18 days.

[0088] During the storage process, the freezing curve was measured. The results showed that although no obvious phase change was found in the temperature curve, the sample temperature dropped to -3°C on the 10th day of storage, and the sample was found to be frozen when it was taken out on the 11th day. Other results are as follows Figure 2-6 shown.

[0089] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for prolonging supercooling of meat products in a magnetic field environment, characterized in that: The method comprises: storing the meat products in a static magnetic field environment at a temperature of -5 to -1°C for 8 to 20 days; wherein the static magnetic field is processed in stages using different magnetic field intensities, first storing at 4 to 6 mT for 5 to 8 days, then storing at 8 to 10 mT for 2 to 5 days, and then storing at 4 to 6 mT for 5 to 8 days.

2. The method according to claim 1, characterized in that: The staged treatment is to first store at 4 mT for 8 days, then at 8 mT for 2 days, and then at 5 mT for 8 days.

3. The method according to claim 1, characterized in that The method comprises the following steps: (1) Pre-processing of fresh meat products; (2) Place the meat product processed in step (1) on a tray and wrap it with plastic wrap; (3) The tray of step (2) is placed in a static magnetic field environment for storage.

4. The method according to claim 3, characterized in that The pretreatment in step (1) is to cut and trim the meat product.

5. The method according to claim 4, characterized in that In step (1), the meat product is cut into suitable size and shape.

6. The method according to claim 3, characterized in that: Step (2) Seal the tray with plastic wrap to prevent the meat from losing a lot of water.

7. The method according to claim 3, characterized in that Step (3) is to store the meat product in a freezer having a freezing function and a magnetic field generating function.

8. The method according to claim 7, characterized in that The freezer is a magnetic field freezer.

9. The method according to claim 1, characterized in that: The meat products include pork, beef, chicken breast, salmon and tuna.

10. Use of the method according to claim 1 in the storage of meat products.

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