阅读说明：本技术 一种低频超声低损快速解冻猪里脊肉的方法 (Method for quickly thawing pork tenderloin by low-frequency ultrasonic low-loss ) 是由 吴平 姚芳 祁兴普 刘萍 王正云 施帅 徐嘉蔓 郑海松 于 2021-09-24 设计创作，主要内容包括：本发明公开了一种低频超声低损快速解冻猪里脊肉的方法,该方法为：在恒温(26℃)水浴的条件下,以60～300W超声强度和22/40kHz超声频率的无间断超声进行解冻,直至猪里脊肉中心温度达到0℃。本发明采用恒温水浴超声发生器进行猪里脊的解冻,相比于传统空气和静水解冻,不仅大幅度缩短了解冻时间、提高了解冻效率,还能最大程度地保留猪里脊肉的原始品质、减少汁液等营养成分的流失、并改善其嫩度。本发明的超声解冻过程操作简便、超声设备成本较低,实用性强且解冻效果理想。(The invention discloses a method for quickly thawing pork tenderloin by low-frequency ultrasonic with low loss, which comprises the following steps: and (3) unfreezing by uninterrupted ultrasound with the ultrasonic intensity of 60-300W and the ultrasonic frequency of 22/40kHz under the condition of constant-temperature (26 ℃) water bath until the central temperature of the pork tenderloin reaches 0 ℃. Compared with the traditional unfreezing in air and still water, the unfreezing time is greatly shortened, the unfreezing efficiency is improved, the original quality of the pork fillet is kept to the maximum extent, the loss of nutritional ingredients such as juice is reduced, and the tenderness of the pork fillet is improved. The ultrasonic thawing process of the invention has simple operation, lower ultrasonic equipment cost, strong practicability and ideal thawing effect.)

1. A method for low-frequency ultrasonic low-loss quick thawing of pork tenderloin, which comprises the following steps: and (3) placing the frozen pork tenderloin in a constant-temperature water bath condition, and carrying out uninterrupted thawing treatment at the ultrasonic intensity of 60-300W, wherein the ultrasonic frequency is 22/40 kHz.

2. The method of claim 1, wherein the duration of the sonication is less than or equal to 8 min.

3. The method for low-frequency ultrasonic low-loss quick thawing of pork tenderloin according to claim 2, wherein the ultrasonic intensity is 240W; the ultrasonic frequency is 22 kHz; the time of sonication was 4.9 min.

4. The method for thawing pork tenderloin with low frequency ultrasound and low loss and rapidity according to any one of claims 1 to 3, characterized in that the thawing treatment is carried out by using a constant temperature water bath type ultrasonic generating device, and the volume of a water bath is 10L.

5. The method for low-frequency ultrasonic low-loss quick thawing of pork tenderloin according to claim 4, wherein the constant-temperature water bath type ultrasonic generating device comprises a constant-temperature water bath and two ultrasonic vibrating plates, and the two ultrasonic vibrating plates are arranged on two sides of the water bath.

6. The method for low-frequency ultrasonic low-loss quick thawing of pork tenderloin according to claim 5, wherein the temperature of the thermostatic water bath is 26 ℃.

7. The method of claim 5, wherein the thawing process further comprises: the central temperature of the pork tenderloin was monitored in real time using a thermocouple thermometer and was considered to be completely thawed when the central temperature reached 0 ℃.

8. The method of claim 5, wherein the pork tenderloin has dimensions of 20 x 20 mm.

9. The method of claim 5, wherein the source of the frozen griskin comprises: freezing fresh pork fillet in a freezing chamber of a refrigerator at the temperature of-18 ℃; or a-18 ℃ cold chain stream derived from pork; or from a low-temperature freezer at-25 to-18 ℃ for preserving frozen pork.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to a method for quickly thawing pork tenderloin with low frequency and ultrasound and low loss.

Background

According to the animal husbandry industry structure in China, the percentage of pork in meat is up to more than 60%, so that China becomes a world large country for pork consumption, and the annual consumption reaches more than 5000 million tons. The pork spine is often used as common meat food on dining tables of people in China because of tender and delicious meat, rich protein content and balanced amino acid composition. Pork raw materials such as pork tenderloin and the like are frozen in the transportation, circulation and storage processes so as to prolong the shelf life of meat and keep the nutritional quality of pork. However, the small ice crystals formed during the freezing process destroy the microstructure of the pork muscle fibers and reduce the water retention rate of the meat, thereby causing the problems of juice loss, cooking loss increase, even meat tenderness reduction and the like of the fillet.

Common methods for thawing pork including fillet are air and still water thawing methods, which not only take long time and have low efficiency, but also have the problems of low thawing uniformity, enzymatic browning, microbial contamination and the like. Therefore, a novel thawing technology aiming at meat is sought, so that the quality of the meat is maintained to the maximum extent, and the significance of improving the edible safety of meat products is achieved.

At present, the novel thawing techniques widely applied at home and abroad comprise microwave thawing, electrolytic freezing, high-pressure thawing, ultrasonic thawing and the like. Microwave thawing is a thawing mode widely applied in families, has the characteristics of high thawing efficiency, strong penetrability and synchronous thawing of the inside and the outside of materials, but has the problem of surface overheating. The characteristics of electrolytic freezing are that the speed of thawing is fast, and it is less to receive the microbial contamination, but the problem of material surface and inside homogeneity of thawing is comparatively outstanding, can appear the surface and be heated to melt the problem of thawing and the core is unfrozen inadequately. High-pressure unfreezing efficiency, small process pollution and higher use cost. For ultrasonic thawing, the cost problem can be well considered while high efficiency, environmental protection and low energy consumption are ensured. For example, chinese patent application publication No. CN206472751U discloses an ultrasonic thawing apparatus for shrimp processing, in which an ultrasonic generator is installed at the bottom of a thawing tank, so that the generated vibration facilitates separation of ice cubes from shrimp and thawing can be completed easily and quickly. Chinese patent application with publication number CN102422875A discloses a method for maintaining quality by combining color protection of folium Artemisiae Argyi pretreatment with ultrasonic quick freezing and thawing, wherein the flavor quality of folium Artemisiae Argyi after thawing is reduced by 6.2% compared with fresh raw materials by ultrasonic treatment of 85W and 200kHz, and the freshness of folium Artemisiae Argyi is retained to the maximum extent. Chinese patent application with publication number CN108719440A discloses a method for unfreezing carp under assistance of ultrasonic waves, wherein ultrasonic waves of 300W and 20kHz are used for unfreezing, the unfreezing time of frozen carp is shortest, the steaming loss rate is lowest, and the taste and quality of unfrozen fish are guaranteed. The above examples of ultrasound applications have demonstrated the feasibility of ultrasound to perform rapid thawing of frozen produce. However, the existing ultrasonic thawing treatment has high use frequency and is easy to cause thermal denaturation of materials; on the other hand, the generator in the ultrasonic device is arranged at the bottom of the thermostatic water bath tank, which can cause that sound energy is dissipated when sound waves generated from the bottom are transmitted to the liquid level in the treatment process, and only a part of sound energy can generate return waves, so that a lot of energy is lost. In addition, previous studies focused on plant species and fish in agricultural products, and there were few reports of ultrasonic thawing studies on livestock and poultry meat with muscle cells significantly different from the former two. Plant cells contain cell walls, and high-frequency ultrasonic waves with larger energy are needed to penetrate through the frozen cell walls when quick thawing is pursued; the fish muscle cell fiber is short, the protein tissue structure is loose, the water content is high, the ultrasonic wave transmission is convenient, and the juice loss rate after unfreezing is small. However, when the livestock meat is red meat, particularly pork, and muscle fibers are thick and thick, the thawing treatment is carried out by improper high-power or high-frequency ultrasound, the water locking capacity of the muscle fibers is reduced, and the juice loss rate is obviously increased; the fat contained in the muscle also accelerates the oxidation, resulting in the reduction of the pork quality.

In view of the above, the invention mainly develops a low-loss quick thawing method specially for the pork tenderloin by applying an improved ultrasonic device and optimized ultrasonic combination parameters in the frozen pork tenderloin for thawing, so as to maximally retain the fresh state of the pork tenderloin and provide a theoretical basis for the application of a low-frequency ultrasonic thawing technology to large-scale thawing of pork products.

Disclosure of Invention

The invention aims to provide a low-loss quick thawing method specially for griskin, namely a low-frequency ultrasonic low-loss quick thawing method for griskin.

The invention is realized by the following technical scheme:

a method for quickly thawing pork tenderloin by low-frequency ultrasonic with low loss comprises the following steps: and (3) placing the frozen pork tenderloin in a constant-temperature water bath condition, and carrying out uninterrupted thawing treatment at the ultrasonic intensity of 60-300W, wherein the ultrasonic frequency is 22/40 kHz.

Further, the time of the ultrasound is less than or equal to 8 min.

Further, the ultrasonic intensity is 240W; the ultrasonic frequency is 22 kHz; the time of sonication was 4.9 min.

Further, the method adopts a constant-temperature water bath type ultrasonic generating device to carry out unfreezing treatment, wherein the volume of a water bath is 10L.

Furthermore, the constant-temperature water bath type ultrasonic generating device comprises a constant-temperature water bath and two ultrasonic vibrating plates, wherein the two ultrasonic vibrating plates are arranged on two sides of the water bath. Compared with an ultrasonic generator with the ultrasonic vibration plates positioned at the bottom, the ultrasonic vibration plate device has the advantages that the two ultrasonic vibration plates are arranged on two sides of the water bath, and each ultrasonic vibration plate can generate transverse ultrasonic waves when working independently, so that the loss of ultrasonic energy at a longitudinal gas/liquid interface is relieved.

Further, the temperature of the thermostatic water bath is 26 ℃.

Further, the thawing process further comprises: the central temperature of the pork tenderloin was monitored in real time using a thermocouple thermometer and was considered to be completely thawed when the central temperature reached 0 ℃.

After thawing, the meat sample is subjected to analytical balance, constant-temperature cooking water bath and texture analyzer to respectively determine the juice loss rate, the cooking loss rate and the shearing force.

Further, the size of the griskin is 20 × 20 × 20 mm.

Further, the source of the frozen griskin comprises: freezing fresh pork fillet in a freezing chamber of a refrigerator; or a-18 ℃ cold chain stream derived from pork; or from a low-temperature freezer at-25 to-18 ℃ for preserving frozen pork.

Compared with the prior art, the invention has the following beneficial effects:

the method has the advantages of low ultrasonic power, low frequency, further reduced energy consumption, small volume of used thawing medium water, and multiple times of thawing treatment after one-time filling. Compared with the air thawing and still water thawing modes, the ultrasonic thawing time is greatly shortened, and 65-79% and 44-68% of treatment time are saved respectively; in addition, the juice loss rate is reduced by 17% -44% and 11% -40%, respectively, and the shear force is reduced by 16% -28% at the maximum (tables 1 and 2). The method has the advantages of simple and convenient operation and low equipment investment, can effectively solve the problems of quality change and the like caused by overlong thawing time of the griskin, has a certain tenderizing effect on the griskin, and has strong practicability.

Drawings

FIG. 1 is an air, still water and ultrasonic thaw curve (22 kHz);

FIG. 2 is an air, still water and ultrasonic thaw curve (40 kHz);

FIG. 3 is a schematic of air, still water and ultrasonic thaw time;

fig. 4 is a schematic view of a constant temperature water bath type ultrasonic generating device.

In the figure, 1-shell, 2-thermostatic water bath, 3-water bath unfreezing medium, 4-ultrasonic vibrating plate (40kHz), 5-heating wire, 6-temperature sensor, 7-temperature control and ultrasonic controller, 8-ultrasonic vibrating plate (22kHz), 9-thermocouple thermometer and 10-thermocouple temperature probe.

Detailed Description

The present invention will be described in detail with reference to examples, but the embodiments are not limited thereto. The technical scheme of the invention is modified or replaced by equivalent, and the modified or replaced technical scheme is covered in the protection scope of the invention.

Pretreatment of pork fillet:

selecting fresh and odorless pork fillet, cutting into 20 × 20 × 20mm cubes, inserting a thermocouple thermometer probe from the middle part of the cube to the midpoint position, packaging with a plastic packaging bag, and storing in a refrigerating chamber of a refrigerator at-20 deg.C.

And (3) unfreezing:

the frozen fillet sample, the plastic packaging bag and the thermocouple thermometer probe are put into a constant temperature water bath containing distilled water of 26 ℃, and the volume of the medium distilled water is 10L. And (3) recording the temperature condition of the Ridge meat every 1min after the ultrasonic generator is started, judging that the Ridge meat is completely thawed when the central temperature of the cube meat reaches 0 ℃, and recording the time taken for the sample to rise from the freezing storage temperature to 0 ℃ as thawing time. Air thawing, still water thawing and ultrasonic thawing curves and thawing times at different powers and frequencies are shown in fig. 1, fig. 2 and fig. 3, respectively.

FIGS. 1 and 2 show that the time for thawing air is longest and the time for thawing still water is less under the condition of constant temperature water bath at 26 ℃; the ultrasonic thawing time is shortest, the central temperature of the fillet sample is rapidly increased from the freezing storage temperature to-6 ℃, the time curve is quite steep, and then the central temperature is slowly increased from-6 ℃ to 0 ℃, which is the temperature at which small ice crystals inside muscles start to change phase and is the key stage of the thawing process. The result shows that the 60-300W ultrasonic wave can shorten the heating time of-6-0 ℃ and reduce the muscle thawing damage no matter under the frequency of 22kHz or 40 kHz. Figure 3 also verifies this result, at 22kHz or 40kHz, the air and still water thawing time is longer than ultrasonic thawing. With the continuous increase of the ultrasonic power, the thawing time is continuously shortened, and the significance of the time shortening after 240W is unchanged.

As shown in the examples below.

Example 1:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 22kHz and the ultrasonic intensity is 60W, the time for completing the unfreezing of the pork fillet in the pork fillet is 7min, which is reduced by 67% compared with the unfreezing in the air and 49% compared with the unfreezing in the still water; at this time, the juice loss rate of the fillet is 5.25 percent, which is respectively reduced by 28 percent and 23 percent compared with the air and still water unfreezing; the cooking loss rate is not obviously different from air and still water thawing, but is higher than that of the fresh fillet; shear force was not significantly different from fresh fillet, air thawed and still thawed meat samples (tables 1 and 2, same below).

Example 2:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 22kHz and the ultrasonic intensity is 120W, the thawing completion time of the pork fillet in the pig is 6min, which is respectively reduced by 72 percent and 57 percent compared with the thawing in air and still water; at this time, the juice loss rate of the fillet is 5.31 percent, which is respectively reduced by 28 percent and 22 percent compared with the air and still water unfreezing; the cooking loss rate is not obviously different from that of air and still water thawing, but is obviously higher than that of the fresh fillet; the shear force was not significantly different from that of fresh fillet, air thawed and still water thawed meat samples.

Example 3:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 22kHz and the ultrasonic intensity is 180W, the thawing completion time of the pork fillet in the pig is 5.6min, which is respectively reduced by 74 percent and 60 percent compared with the thawing in air and still water; at this time, the juice loss rate of the fillet is 4.05 percent, which is respectively reduced by 44 percent and 40 percent compared with the air and still water unfreezing; the cooking loss rate is not obviously different from that of air and still water thawing, but is obviously higher than that of the fresh fillet; shear force was not significantly different from fresh tenderloin and air thawed meat samples, but significantly thawed meat samples with still water.

Example 4:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 22kHz and the ultrasonic intensity is 240W, the thawing completion time of the pork fillet in the pig is 4.9min, which is respectively reduced by 77% and 65% compared with the thawing in air and still water; at this time, the juice loss rate of the fillet is 4.54 percent, which is respectively reduced by 37 percent and 33 percent compared with the air and still water unfreezing; the cooking loss rate is not obviously different from that of air and still water thawing, but is obviously higher than that of the fresh fillet; shear forces are significantly lower than for fresh fillet, air thawed and still thawed meat samples.

Example 5:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 22kHz and the ultrasonic intensity is 300W, the thawing completion time of the pork fillet in the pig is 4.5min, which is respectively reduced by 79% and 68% compared with the thawing in air and still water; at this time, the juice loss rate of the fillet is 5.59 percent, which is reduced by 23 percent and 18 percent compared with the air and still water unfreezing respectively; the cooking loss rate is not obviously different from that of air and still water thawing, but is obviously higher than that of the fresh fillet; shear forces are significantly lower than for fresh fillet, air thawed and still thawed meat samples.

Example 6:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 40kHz and the ultrasonic intensity is 60W, the thawing completion time of the pork fillet in the pig is 7min, which is respectively reduced by 65% and 44% compared with the thawing in air and still water; at this time, the juice loss rate of the fillet is 5.63 percent, which is reduced by 22 percent and 17 percent compared with the air and still water unfreezing respectively; the cooking loss rate is not obviously different from air thawing, but is obviously higher than that of fresh tenderloin and meat samples thawed in still water; the shear force is significantly higher than for fresh fillet, air thawed and still water thawed meat samples.

Example 7:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 40kHz and the ultrasonic intensity is 120W, the thawing completion time of the pork fillet in the pig is 5.8min, which is respectively reduced by 71 percent and 54 percent compared with the thawing in air and still water; at this time, the juice loss rate of the fillet is 5.78 percent, which is respectively reduced by 20 percent and 15 percent compared with the air and still water unfreezing; the cooking loss rate is not obviously different from that of air thawing and still water thawing, but is obviously higher than that of the fresh fillet; the shear force was not significantly different from that of fresh fillet, air thawed and still water thawed meat samples.

Example 8:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 40kHz and the ultrasonic intensity is 180W, the thawing completion time of the pork fillet in the pig is 5.1min, which is respectively reduced by 75 percent and 60 percent compared with the thawing in air and still water; the juice loss rate of the fillet is 4.88 percent at the moment, which is respectively reduced by 33 percent and 28 percent compared with the air and still water unfreezing; the cooking loss rate is obviously higher than that of the fresh tenderloin, the thawed meat sample of air and still water; shear forces are significantly lower than for fresh fillet, air thawed and still thawed meat samples.

Example 9:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 40kHz and the ultrasonic intensity is 240W, the thawing completion time of the pork fillet in the pig is 4.5min, which is respectively reduced by 78% and 64% compared with the thawing in air and still water; at this time, the juice loss rate of the fillet is 4.44 percent, which is respectively reduced by 39 percent and 35 percent compared with the air and still water unfreezing; the cooking loss rate is not obviously different from air thawing, but is obviously higher than that of fresh tenderloin and meat samples thawed in still water; shear forces are significantly lower than for fresh fillet, air thawed and still thawed meat samples.

Example 10:

under the condition of constant-temperature water bath at 26 ℃, when the frequency is 40kHz and the ultrasonic intensity is 300W, the thawing completion time of the pork fillet in the pig is 4.7min, which is respectively reduced by 77% and 63% compared with the thawing in air and still water; at the moment, the juice loss rate of the fillet is 6.02 percent, which is respectively reduced by 17 percent and 11 percent compared with the air and still water unfreezing; the cooking loss rate is not obviously different from air thawing, but is obviously higher than that of fresh tenderloin and meat samples thawed in still water; shear forces are significantly lower than for fresh fillet, air thawed and still thawed meat samples.

TABLE 1 Effect of different thawing modes on juice loss, boil loss and shear (22kHz)

Note: the same column of numbers with different upper case letters indicates significant differences (p < 0.05).

TABLE 2 Effect of different thawing modes on juice loss, boil loss and shear (40kHz)

Note: the same column of numbers with different upper case letters indicates significant differences (p < 0.05).

The results of the above examples show that when the ultrasonic frequency is 22/40kHz and the ultrasonic intensity is 240W, the thawing of the pork fillet in the pork fillet can be completed in 4.9 and 4.5min respectively, and compared with air thawing and still water thawing, the thawing efficiency is remarkably improved by 77% and 64% respectively. The juice loss rate is respectively and obviously reduced by 39% -44% and 35% -40% compared with that of the meat sample of an air and still water unfreezing group. Although the cooking loss rate is increased compared with that of the fresh fillet, the shearing force is remarkably reduced by 12 to 15 percent due to the action of ultrasonic waves, and the tenderness and quality of the meat are improved. The low-frequency ultrasound realizes low-loss quick thawing of the pork tenderloin and furthest retains the freshness of the pork tenderloin.