Unfreezing method and application thereof

Abstract

The invention discloses an unfreezing method and application thereof, and relates to the technical field of meat unfreezing. According to the method, the thawing time is remarkably shortened by using the high-voltage electrostatic field, and the thawing rate of the chicken is increased. The high-voltage electrostatic field can generate ionic wind, so that convection heat and mass transfer of frozen products are accelerated, the heat transfer coefficient of the surfaces of the products is increased, and the effects of shortening the unfreezing time and improving the chicken unfreezing rate are achieved. In addition, the method can also significantly reduce the thawing loss of the product, promote the acid discharge of the product so as to improve the flavor and taste of meat, delay the increase of a color difference value, reduce the influence of thawing on the color of the product, reduce the shearing force of the product so as to improve the tenderness of the product, reduce the water loss of the product and slow down the fat oxidation speed of chicken.

Description

Technical Field

[0001] The present invention relates to the technical field of meat thawing, and particularly relates to a thawing method and its application. Background Art

[0002] Meat often spoils and deteriorates during storage, production, processing, and transportation, causing significant economic losses and endangering human health. To ensure the quality and economic value of food, meat is often stored and transported in a frozen manner. The thawing process consumes a large amount of energy and may lead to deterioration of product quality. During the thawing process, due to changes in the myofibril structure, protein and lipid oxidation, etc., the product quality deteriorates, which greatly affects aspects such as the texture, flavor, color, and nutritional value of the product, resulting in losses.

[0003] Currently, the thawing methods used include traditional thawing methods in air, water, and refrigerators, as well as many emerging thawing methods, such as Ohmic thawing, ultrasonic thawing, radio frequency thawing, microwave thawing, far-infrared thawing, etc. The most widely used traditional thawing methods have significant drawbacks. They not only require a large amount of time but also cause serious damage to product quality. The electroperforation that may occur during Ohmic thawing can cause adverse changes in the color and flavor of meat. The poor penetration of ultrasonic thawing can lead to local overheating on the product surface. The radio frequency thawing field is prone to the tip effect, resulting in local overheating of food. Microwave thawing is prone to uneven thawing, causing inevitable thermal damage to the product. The disadvantages of far-infrared thawing are similar to those of microwave thawing, including uneven thawing, too high surface temperature, and product dehydration.

[0004] In summary, it is necessary to develop a new type of thawing method to reduce the impact of the thawing process on meat quality. Summary of the Invention

[0005] [Technical Problem]

[0006] The technical problem to be solved by the present invention is: to provide a thawing method that reduces the impact of the thawing process on meat quality.

[0007] [Technical Solution]

[0008] To solve the above technical problem, the present invention provides the following technical solution:

[0009] In the first aspect, the present invention provides a meat thawing method, including the following steps:

[0010] S1. Place the frozen meat in an electrostatic field thawing device;

[0011] S2. Set the thawing mode of the electrostatic field thawing device as follows: First stage: 18 - 22°C, 1 - 3 h; Second stage: 8 - 12°C, 2 - 4 h; Third stage: 2 - 6°C, 1 - 3 h.

[0012] In one embodiment, the voltage of the electrostatic field is 2.0 - 4.0 kV. Optionally, the voltage of the electrostatic field is 3.0 kV.

[0013] In one embodiment, the temperature in the first stage is 20°C, the temperature in the second stage is 10°C, and the temperature in the third stage is 4°C.

[0014] In one embodiment, the thawing mode is: First stage: 20°C, 2 h; Second stage: 10°C, 3 h; Third stage: 4°C, 2 h.

[0015] In one embodiment, the meat includes chicken.

[0016] In a second aspect, the present invention also provides an application of the method described in the first aspect in thawing meat products.

[0017] In one embodiment, the application includes: reducing thawing loss of meat products, promoting acid discharge of meat products, delaying the growth of color difference values of meat products, improving the texture of meat products, reducing the shear force of meat products, improving the water - holding performance of meat products, and / or reducing lipid oxidation of meat products.

[0018] 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 below (such as in the embodiments) can be combined with each other, thereby constituting new or preferred technical solutions. Due to space limitations, they will not be elaborated one by one here.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The method of the present invention significantly shortens the thawing time and improves the thawing rate of chicken by using a high - voltage electrostatic field. The high - voltage electrostatic field can generate an ionic wind, thereby accelerating the convective heat and mass transfer of frozen products, increasing the heat transfer coefficient on the product surface, and thus achieving the effects of shortening the thawing time and improving the thawing rate of chicken. In addition, the method of the present invention can also significantly reduce the thawing loss of products, promote acid discharge of products to improve the flavor and taste of meat, delay the growth of color difference values to reduce the impact of thawing on product color, reduce the shear force of products to improve the tenderness of products, reduce water loss of products, and slow down the speed of chicken fat oxidation. Description of the Drawings

[0021] Figure 1: Effects of different thawing methods on the thawing time of butter chicken, where HC: thawing without static electricity at 25°C; HH: thawing with static electricity at 25°C; TC: three-stage thawing without static electricity; TH: three-stage thawing with static electricity; different superscript letters represent significant differences in the same index (p < 0.05), the same below.

[0022] Figure 2 : Effects of different thawing methods on the thawing rate of butter chicken.

[0023] Figure 3 : Thawing curves of butter chicken under different thawing methods.

[0024] Figure 4 : Effects of different thawing methods on the thawing loss of butter chicken.

[0025] Figure 5 : Effects of different thawing methods on the pH of butter chicken.

[0026] Figure 6 : Effects of different thawing methods on the color change of butter chicken, where A: effects of different thawing methods on the L* value of butter chicken; B: effects of different thawing methods on the a* value of butter chicken; C: effects of different thawing methods on the b* value of butter chicken; D: effects of different thawing methods on the ΔE of butter chicken.

[0027] Figure 7 : Effects of different thawing methods on the texture properties of butter chicken, where A: effects of different thawing methods on the hardness of butter chicken; B: effects of different thawing methods on the elasticity of butter chicken; C: effects of different thawing methods on the cohesiveness of butter chicken; D: effects of different thawing methods on the chewiness of butter chicken; E: effects of different thawing methods on the resilience of butter chicken.

[0028] Figure 8 : Effects of different thawing methods on the shear force of butter chicken.

[0029] Figure 9 : Effects of different thawing methods on the water-holding performance of butter chicken, where A: effects of different thawing methods on the cooking loss of butter chicken; B: effects of different thawing methods on the drip loss of butter chicken; C: effects of different thawing methods on the centrifugal loss of butter chicken; D: effects of different thawing methods on the total loss of butter chicken.

[0030] Figure 10 : Effects of different thawing methods on the lipid oxidation of butter chicken. Specific implementation manners

[0031] The present invention will be further described in detail below in conjunction with specific embodiments. The provided embodiments are only for clarifying the present invention and not for limiting the scope of the present invention. The following provided embodiments can be used as a guide for those of ordinary skill in the art to make further improvements and do not constitute any limitation to the present invention in any way.

[0032] In the present invention, the term "about" or "approximately" should be understood to include all values within the allowable measurement error range.

[0033] The type of chilled chicken sample used in the present invention is butter chicken, with a specification of 0.8 - 1.0 kg, an age of approximately 60 days, sourced from Guangdong Wenshi Jiarun Food Co., Ltd. The product is packaged in a special packaging bag, frozen in the warehouse on the day of slaughter following production, and stored until the central temperature of the carcass reaches -20°C before being taken out of the warehouse and transported to the laboratory for thawing by refrigerated transportation.

[0034] The high-voltage electrostatic field thawing device (output 3 KVAC), model BMT-JD010, is purchased from Shandong Bomeite Electric Technology Co., Ltd.

[0035] The color difference meter, model CR-400, is purchased from Konica Minolta Co., Ltd. of Japan.

[0036] The meat pH value direct measuring instrument, model PH-STAR, is purchased from Mettler Toledo GmbH of Germany.

[0037] The texture analyzer, model TA.XT PlusC, is purchased from Stable Micro Systems Co., Ltd. of the UK.

[0038] The digital display muscle tenderness meter, model C-LM3B, is purchased from Nanjing Mingao Instrument Equipment Co., Ltd.

[0039] The multifunctional microplate reader, model infinite200 Pro, is purchased from Tecan (Shanghai) Trading Co., Ltd.

[0040] The experimental methods in the following embodiments, unless otherwise specified, are all conventional methods and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following embodiments, unless otherwise specified, can all be obtained from commercial channels.

[0041] Example:

[0042] Example 1 Influence of High-Voltage Electrostatic Field on Thawing of Butter Chicken

[0043] Taking 0.8 - 1.0 kg of butter chickens as the experimental objects, after being treated with high voltage electric field (HVEF), they were compared with butter chickens without HVEF treatment to compare the differences in thawing rate, thawing loss, color difference, pH, texture characteristics, tenderness, water - holding capacity, and TBA value between the two groups.

[0044] I. Treatment of raw materials

[0045] After 0.8 - 1.0 kg of butter chickens were slaughtered and packaged on the production line, they were placed in a freezer at about - 20 °C for freezing storage. After freezing, the butter chickens were thawed with different thawing methods while still in the package. The grouping is as follows:

[0046] 1) HC group: Ordinary refrigerator at 25 °C (control group 1);

[0047] 2) HH group: High - voltage electrostatic field refrigerator at 25 °C (voltage condition 3.0 kV) (experimental group 1);

[0048] 3) TC group: Three - stage mode (thawing mode one: 20 °C for 2 h, thawing mode two: 10 °C for 3 h, thawing mode three: 4 °C for 2 h) ordinary refrigerator (control group 2);

[0049] 4) TH group: Thawing was carried out in a high - voltage electrostatic field refrigerator (3.0 kV) with a three - stage mode (thawing mode one: 20 °C for 2 h, thawing mode two: 10 °C for 3 h, thawing mode three: 4 °C for 2 h) (experimental group 2).

[0050] When the central temperature reached 0 °C, it was considered that the thawing was completed. After thawing, the samples were stored in a 4 °C refrigerator for further testing. The experiment was repeated three times and the average value was taken.

[0051] II. Differences in thawing rate, thawing loss, color difference, pH, texture characteristics, tenderness, water - holding capacity, and TBA value among different thawing methods

[0052] (1) Effects of different thawing methods on the thawing time and thawing rate of butter chickens

[0053] Measurement of the time required for thawing: The thermometer probe was inserted into the center of the chicken breast at the same angle and the same depth and fixed. The central temperature of the chicken breast after thawing by different thawing methods and the time used for different thawing methods were recorded respectively. The formula for calculating the thawing rate is as follows:

[0054] V = ΔT / t Formula (1)

[0055] In the formula: V, thawing rate, °C / min; ΔT, the temperature difference between the initial temperature and the temperature at the end of thawing, °C; t, the time used for thawing, min.

[0056] Taking the time elapsed for the central temperature of the butter chicken carcass to rise from -18 °C to 0 °C as the thawing time, the thawing times ( Figure 1 ) and thawing rates ( Figure 2 ) of different treatment methods are shown in Table 1, and the thawing curves of different thawing methods are as shown in Figure 3 . It can be seen from Table 1 that the thawing times of thawing without static electricity at 25 °C, thawing with static electricity at 25 °C, three-stage thawing without static electricity, and three-stage thawing with static electricity are 190.83 min, 70 min, 1247.5 min, and 310 min respectively. There are significant differences in the thawing times of the four thawing methods (p < 0.05). Among them, the thawing time of thawing with static electricity at 25 °C is the shortest, the thawing rate is the fastest, and the efficiency is the highest. The thawing rate is the ratio of the temperature difference before and after thawing of the butter chicken to the time, indicating the overall speed of thawing, and is inversely proportional to the thawing time. The thawing rates from high to low are thawing with static electricity at 25 °C > thawing without static electricity at 25 °C > three-stage thawing with static electricity > three-stage thawing without static electricity. Similarly, different thawing methods have a significant impact on the thawing rate of chicken (p < 0.05). At the same temperature: the thawing rate after applying a high-voltage electrostatic field at 25 °C is increased by 63.32% compared with that without an electrostatic field; in the three-stage thawing mode, the thawing rate after applying a high-voltage electrostatic field is increased by 75.15% compared with that without an electrostatic field.

[0057] Therefore, it can be concluded that thawing under HVEF can significantly and positively affect the thawing time of the whole chicken, and the thawing rate of the chicken is significantly improved. The main reason for the impact on the thawing rate is the generation of ion wind under the action of HVEF. High-voltage discharge can generate an ionized neutral fluid and form a plasma region around the electrode. When the electrode voltage is relatively high, local breakdown will occur in the surrounding air medium, resulting in phenomena such as corona discharge. This causes the charged particles in the air to move in a directional manner and obtain energy, thus forming an "ion wind", which is the so-called corona wind. When the ion wind contacts the food, it accelerates the convective heat and mass transfer of the frozen food. Due to the eddy currents and turbulences generated by the ion wind, the heat transfer coefficient on the surface of the object increases, improving the thawing rate. Therefore, the time required for thawing the butter chicken under a high-voltage electrostatic field is significantly shorter than that without high-voltage electrostatic treatment.

[0058] Table 1 Effects of different thawing methods on the thawing time and thawing rate of butter chicken

[0059]

[0060] Note: HC: Thawing without static electricity at 25 °C; HH: Thawing with static electricity at 25 °C; TC: Three-stage thawing without static electricity; TH: Three-stage thawing with static electricity; Different lowercase letters in the same column indicate significant differences (p < 0.05), the same below.

[0061] (2) Effects of different thawing methods on the thawing loss of butter chicken

[0062] Before thawing the butter chicken, weigh its mass \(m_1\) (g). After thawing, dry the surface juice and weigh its mass \(m_2\) (g). Calculate the thawing loss rate according to formula (2):

[0063]

[0064] Where: \(X\) is the thawing loss, %; \(m_1\) is the mass before thawing, g; \(m_2\) is the mass after thawing, g.

[0065] The results of thawing loss of butter chicken under different thawing methods are as Figure 4 shown in Table 2. The thawing losses of high-temperature non-static electricity, high-temperature static electricity, three-stage non-static electricity, and three-stage static electricity thawing are 1.65%, 1.65%, 1.59%, and 1.41% respectively. It can be seen from Table 2 that there is no obvious difference in the thawing loss between high-temperature non-static electricity and three-stage non-static electricity thawing, but both are significantly greater than high-temperature static electricity and three-stage static electricity thawing. Among the four thawing methods, the thawing loss of three-stage static electricity is the smallest. At the same high temperature (25°C), there is no significant difference in the thawing loss between applying an electrostatic field and not applying an electrostatic field, but there is a significant difference between the two under three-stage mode thawing (p < 0.05).

[0066] Table 2 Effects of different thawing methods on the thawing loss of butter chicken

[0067]

[0068] (3) Effects of different thawing methods on the pH of butter chicken

[0069] Insert the measuring probe of the in-line pH meter for carcass into the center of the chicken breast of the butter chicken. Before measurement, calibrate and verify the instrument with calibration solutions of pH 4.01 and pH 7.00. At the same time, measure the central temperature of the sample measurement part with a thermometer and select the corresponding temperature on the temperature setting interface of the pH meter. After completing the calibration preset, insert the pH meter into the inside of the chicken breast meat at the same angle, ensure that the insertion depth is the same each time, and wait for the instrument to stabilize before reading. Set 3 parallels and 3 replicates for each group, and take the average value as the final pH value.

[0070] To a certain extent, pH can also directly reflect the state of meat, which is not only a direct manifestation of muscle acidity, but also can well reflect the quality of meat. The pH measurement results are as Figure 5As shown in Table 3, it can be seen from Table 3 that there is no significant difference in pH between fresh chicken and that under the conditions of high-temperature static-free and three-stage static-free thawing (p>0.05), but there are significant differences in pH compared with that under high-temperature static thawing and three-stage high-voltage static thawing (p<0.05). This indicates that the high-voltage electrostatic field has the effect of promoting acid discharge in meat, resulting in a decrease in the pH value of the meat. The pH of the samples thawed by three-stage high-voltage static thawing decreased more significantly. Considering that in the three-stage thawing mode, the thawing time of the meat is longer and the acid discharge effect of the high-voltage electrostatic field is more obvious. The meat after acid discharge has a higher maturity, and the flavor and taste of the meat are better.

[0071] Table 3 Effects of different thawing methods on the pH of butter chicken

[0072]

[0073] (4) Effects of different thawing methods on the color change of butter chicken

[0074] After thawing, the butter chicken breast was placed flat upward. Using a CR-400 precision color difference meter, after calibrating with a standard white board, the color difference of the sample was measured. Under natural light, the meat color values L* (surface brightness), a* (redness), and b* (yellowness) of the meat on the bone side of each sample breast muscle block were measured. The color deviation ΔE was calculated using the measured L*, a*, and b* values. The calculation formula is shown in Formula (3).

[0075] Three parallel samples were randomly set in each group, and 5 points were selected at fixed positions for each sample to measure and calculate their average values. The meat color measurement uses the L*, a*, and b* three-color system of the CIELAB system, the light source is selected as C, and the observer's field of view angle is 2°.

[0076] The experiment was repeated 3 times.

[0077]

[0078] In the formula: L*, a*, and b* are the brightness value, redness value, and yellowness value of the processed sample respectively; L0*, a0*, and b0* are the brightness value, redness value, and yellowness value of the fresh sample respectively.

[0079] The results are as Figure 6As shown in Table 4, it can be seen from Table 4 that there are no significant differences in the L* value of the skin of butter chicken thawed under high temperature without static electricity, high temperature with static electricity, and three-stage static electricity thawing (p>0.05), while the L* value of butter chicken thawed by three-stage static electricity thawing is significantly lower (p<0.05) than that of the other three thawing methods. There are no significant differences in the redness value and yellowness value of butter chicken under the four thawing methods (p>0.05). The color difference value △E is an index comprehensively measuring the color change of meat. Compared with fresh butter chicken, the color difference values of high temperature without static electricity and three-stage without static electricity thawing are the largest, but there is no significant difference between them (p>0.05). The data results show that compared with the control group, the treatment with high-voltage electrostatic field can significantly delay the increase of the color difference value (p<0.05).

[0080] Table 4 Effects of different thawing methods on the color change of butter chicken

[0081]

[0082]

[0083] (5) Effects of different thawing methods on the texture properties and shear force of butter chicken

[0084] Texture measurement method:

[0085] Cut the chicken breast into cubes with a size of 1 cm×1 cm×0.5 cm, and use a TA-XT plus C texture analyzer to measure the hardness (g), elasticity (mm), cohesiveness, chewiness (g×mm), and resilience index of the chicken breast.

[0086] The parameters are as follows: TPA mode; pre-test probe speed: 2.00 mm / s; test probe speed: 1.00 mm / s; post-test probe speed: 1.00 mm / s; time interval between two tests: 5.00 s; test compression ratio: 50%; trigger force: 5.00 g; probe model: P / 75; 6 parallels are set for the measurement, and the experiment is repeated 3 times.

[0087] Shear force measurement method:

[0088] Cut the cooked chicken breast samples into long strips with a size of 3 cm×1 cm×0.5 cm, and cut them under a digital muscle tenderness meter. When cutting, the direction of muscle fibers is perpendicular to the cutting direction, and the maximum force required to cut the long strip meat sample is recorded as the shear force of the sample.

[0089] The measurement results of texture and shear force are as Figure 7 、 8As shown in Table 5, it can be seen from Table 5 that the hardness of three-stage static thawing is slightly lower than that of freshly slaughtered ones, but the difference is not significant (p>0.05), and the hardness under other thawing methods decreases significantly (p<0.05); there is no significant difference in the elasticity of three-stage thawing and that of freshly slaughtered samples (p>0.05), but the elasticity of thawing under high-temperature mode is significantly lower than that of fresh samples (p<0.05); there is no significant difference in the cohesiveness of chicken under the four thawing methods and that of fresh samples (p>0.05); there is no significant difference in the chewiness of samples under high-temperature static thawing and three-stage static thawing compared with fresh samples (p>0.05), while the chewiness of samples under high-temperature non-static thawing and three-stage non-static thawing is significantly lower than that of fresh samples (p<0.05); the resilience under three-stage static thawing is significantly lower than that of fresh samples (p<0.05), and there is no significant difference in the resilience of chicken under the other three thawing methods compared with fresh chicken (p>0.05); the shear force can reflect the tenderness of meat. The greater the shear force, the more tough the muscle; the smaller the shear force, the better the tenderness. There are significant differences in the shear force of chicken under the four thawing methods and that of fresh samples (p<0.05). Among them, the shear force of chicken under high-temperature static thawing and three-stage static thawing is the smallest, indicating that high-voltage static electricity has a certain promoting effect on the post-slaughter ripening of chicken and can improve the tenderness of the product.

[0090] Table 5 Effects of Different Thawing Methods on the Texture Characteristics and Shear Force of Butter Chicken

[0091]

[0092] (6) Effects of Different Thawing Methods on the Water-Holding Capacity of Butter Chicken

[0093] The total loss rate of meat thawing can reflect its water-holding capacity. The lower the total loss rate, the better the water-holding capacity. The water-holding capacity of meat is the ability of muscle to maintain its initial moisture content and absorb moisture when subjected to actions such as pressure, heat, chopping, freezing, thawing, etc. during processing or storage. The water-holding capacity is an important indicator for evaluating meat and meat products and can affect various aspects such as the weight, loss rate, tenderness, color, and aroma of meat during storage and transportation. The cooking loss, drip loss, centrifugal loss, and total loss of fresh samples are the smallest.

[0094] a. Cooking Loss

[0095] Samples were taken from the four treatment groups after thawing was completed, and samples from different treatment groups were measured simultaneously at the same time point. The sample weight was approximately 20.00 ± 0.05 g, denoted as (M1), placed in a sterile bag, the air in the bag was pumped out and sealed. Subsequently, the samples in the bag were cooked in a constant temperature water bath at 80 °C for 20 min, and the cooking was stopped when the central temperature of the samples stabilized at 70 °C, and the samples were cooled to room temperature under running water. The surface moisture of the samples was blotted dry with filter paper. This weight was denoted as M2. The cooking loss was calculated according to formula (4):

[0096]

[0097] b. Drip loss

[0098] Take chicken breast, remove the surface fat and fascia, and trim it into strips about 1×2×3 cm and about 5 g, accurately weigh (M3), make a hanging wire with a paper clip in a disposable paper cup, hang the weighed meat on the wire (try not to let the trimmed meat touch the inner wall of the paper cup), seal the paper cup with plastic wrap, place it in a refrigerator at 0 - 4 °C, take out the meat block after 24 h, blot the surface moisture dry with filter paper and then measure the weight (M4). The drip loss was calculated according to formula (5):

[0099]

[0100] c. Centrifugation loss

[0101] The sample used to measure the centrifugation loss was weighed as 1.00 ± 0.02 g (M5), placed in a 1.5 mL microcentrifuge tube, and centrifuged at 8000×g for 30 min at 4 °C. Blot the moisture dry with filter paper and weigh (M6). The centrifugation loss was calculated according to formula (6):

[0102]

[0103] d. Total loss

[0104] The total loss is the sum of the evaporation loss rate, drip loss rate and cooking loss rate. The total loss rate of meat thawing can reflect its water retention property, and the lower the total loss rate, the better the water retention property. The total loss was calculated according to formula (7).

[0105] Total loss (%) = Cooking loss (%) + Drip loss (%) + Centrifugation loss (%) Formula (7)

[0106] The results are as Figure 9As shown in Table 6, for cooking loss, there was no significant difference between high-temperature non-electrolytic thawing and three-stage non-electrolytic thawing (p > 0.05), but the cooking loss of high-temperature electrolytic thawing and three-stage electrolytic thawing was significantly lower than that of high-temperature non-electrolytic thawing and three-stage non-electrolytic thawing (p < 0.05); the drip loss and centrifugal loss of chicken were the largest under high-temperature non-electrolytic thawing, and the drip loss of meat under the other three thawing methods was significantly lower than that under high-temperature non-electrolytic thawing (p < 0.05), but there was no significant difference among them (p > 0.05); in terms of the total loss rate, the loss of chicken was the largest under high-temperature non-electrolytic thawing, and the total loss of meat under the other three thawing methods was significantly lower than that under high-temperature non-electrolytic thawing (p < 0.05), but there was no significant difference in the total loss among the three thawing methods (p > 0.05). Therefore, from the perspective of thawing temperature, the three-stage temperature mode can better retain the moisture in the meat and reduce the loss of moisture compared with high temperature; from the influence of high-voltage electrostatic field, applying a high-voltage electrostatic field during thawing can show a positive effect on the water-holding capacity of chicken, retaining water molecules during the chicken thawing stage, which is attributed to the reduction of the loss of free water and immobilized water by the high-voltage electrostatic field. This may be because water molecules usually change their structural arrangement outside the electric field and arrange in a specific order. Under the action of the electrostatic field, the stability of water molecules in the myofibril gap is improved, and the loss of moisture is reduced.

[0107] Table 6 Effects of different thawing methods on the water-holding performance of butter chicken

[0108]

[0109] (7) Effects of different thawing methods on the lipid oxidation of butter chicken

[0110] After removing the skin, visible surface fat and connective tissue from the butter chicken, it was mixed as a test sample according to the ratio of breast meat: leg meat = 1.5:1.

[0111] The determination of TBARs value referred to the malondialdehyde (MDA) content detection kit (Beijing Solarbio Science & Technology Co., Ltd.). The TBARs value of the sample was expressed as the content of malondialdehyde (MDA) (MDA mg / kg). Each sample group was measured in parallel 3 times, and the experiment was repeated 3 times.

[0112] The results are as Figure 10As shown in Table 7, the malondialdehyde contents of butter chickens after fresh slaughter and treatment with four thawing methods were 0.303 mg / kg, 0.379 mg / kg, 0.327 mg / kg, 0.337 mg / kg, and 0.299 mg / kg, respectively. It can be seen from Table 7 that the degree of fat oxidation in chicken was the greatest under high-temperature non-static thawing. There was no significant difference in the degree of fat oxidation in chicken under high-temperature static thawing and three-stage non-static thawing (p > 0.05). Moreover, the degree of fat oxidation in the first three thawing methods (high-temperature non-static thawing, high-temperature static thawing, three-stage non-static thawing) was greater than that of the fresh slaughter sample (p < 0.05). The degree of fat oxidation in chicken under three-stage static thawing was significantly lower than that of the fresh slaughtered butter chicken sample (p < 0.05). This indicates that the high-voltage electrostatic field can better slow down the rate of fat oxidation and maintain the freshness of chicken. During low-temperature long-time thawing, to a certain extent, the high-voltage electrostatic field can even inhibit the fat oxidation of chicken. It is considered that the electrostatic induction of HVEF may cause the chicken surface to be charged, reducing the contact frequency between the chicken surface and the surrounding oxygen, thus slowing down the rate of chicken fat oxidation. In addition, during the HVEF thawing process, the air is ionized to generate atmospheric pressure plasma. The active nitrogen and other substances rich in the atmospheric plasma move directionally under the action of the electric field. When approaching the chicken surface, they combine with water and are injected into the meat to form nitrite. The nitrite combines with hemoglobin and myoglobin to form nitrohemoglobin and nitrosomyoglobin, forming stable compounds and reducing the iron utilization rate, thereby inhibiting lipid oxidation. On the other hand, HVEF can inhibit the growth of microorganisms, thereby preventing the lipid oxidation of chicken. Finally, HVEF has a positive impact on the quality of chicken by inhibiting the lipid oxidation of chicken. Fat oxidation will cause the food to produce bad odors, affecting the quality and taste of the food. HVEF can maintain the original flavor and texture of the meat product by inhibiting fat oxidation, improving the consumer's eating experience. Secondly, fat oxidation will cause fat deterioration, producing peroxides and other harmful substances. These substances not only affect the safety of the food but also shorten the shelf life of the food. By inhibiting fat oxidation, the oxidative deterioration process of the food can be slowed down, the storage time of chicken can be extended, the generation of toxic compounds can be reduced, ensuring the quality stability during storage and transportation and guaranteeing the eating health of consumers. In addition, fat oxidation may affect the water retention of meat, resulting in water loss and quality decline. Inhibiting fat oxidation can improve the water retention of meat, making the product more juicy and tender, and enhancing the eating experience. In short, three-stage high-voltage static thawing can inhibit the fat oxidation of meat, reduce food waste caused by oxidative deterioration, lower production costs, maintain meat quality, extend the shelf life, and improve nutritional value.

[0113] Table 7 Effects of Different Thawing Methods on Lipid Oxidation of Butter Chicken

[0114]

[0115] Although the present invention has been disclosed above in the preferred embodiments, it is not intended to limit the present invention. Anyone skilled in this technology can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A method for thawing meat, characterized in that, It includes the following steps: S1. Place the frozen meat in an electrostatic field thawing device; S2. Set the thawing mode of the electrostatic field thawing device as follows: the first stage: 18 - 22°C, 1 - 3 h, the second stage: 8 - 12°C, 2 - 4 h, the third stage: 2 - 6°C, 1 - 3 h.

2. The method according to claim 1, characterized in that, The voltage of the electrostatic field is 2.0 - 4.0 kV.

3. The method according to claim 2, wherein The voltage of the electrostatic field is 3.0 kV.

4. The method according to claim 1, characterized in that, The temperature of the first stage is 20°C, the temperature of the second stage is 10°C, and the temperature of the third stage is 4°C.

5. The method according to claim 4, wherein The thawing mode is: the first stage: 20°C, 2 h, the second stage: 10°C, 3 h, the third stage: 4°C, 2 h.

6. The method according to claim 1, wherein The meat includes chicken.

7. The application of the method according to any one of claims 1 - 6 in thawing meat products.

8. The application according to claim 7, wherein The application includes: reducing thawing loss of meat products, promoting acid discharge of meat products, delaying the increase of color difference value of meat products, improving the texture of meat products, reducing the shear force of meat products, improving the water - holding performance of meat products, and / or reducing lipid oxidation of meat products.

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