A chicken alternating dual-frequency ultrasonic tenderizing method and device

Abstract

The present invention provides a method for tenderizing eliminated laying hens with alternating dual-frequency ultrasound, comprising the following steps: pre-treating the breast meat of eliminated laying hens, and then using a tenderizer to perform coordinated ultrasound treatment, to obtain the result; the tenderizer includes calcium chloride and protease; the ultrasound is alternating dual-frequency ultrasound (22 / 40kHz). The ultrasonic device of the present invention adopts a concentric circle arrangement mode of ultrasonic vibrators, which can provide an external uninterrupted alternating dual-frequency ultrasonic physical field for the entire tenderizing process of eliminated laying hens, and maximize the penetration of calcium chloride and protease solution into the deep layer of muscle tissue. The former calcium chloride can increase the ion strength in the muscle, improve the ion distribution, and enhance the water retention of muscle fibers; the latter protease hydrolyzes and refines the muscle fibers, disintegrates the macromolecular protein of the muscle fibers, and reduces the shear force, thereby improving the tenderness of the eliminated laying hens.

Description

Technical Field

[0001] The invention relates to the technical field of food, and in particular to a method and a device for tenderizing chicken of discarded laying hens. Background Art

[0002] Culled laying hens refer to hens that have been eliminated from farms due to low egg production rates and serious decline in egg quality. Despite this, culled laying hens are also a good source of animal protein, but due to their old age and the fact that they consume too much of their own nutrients in laying eggs, resulting in rough meat and low tenderness, the processing utilization rate and high-quality meat output rate of culled laying hens are low. my country is a major laying hen breeding country in the world, with nearly 2 billion laying hens eliminated from farms each year. The wide range of sources of culled laying hen meat and the low utilization rate of meat have resulted in a serious economic burden on my country's laying hen breeding companies. Therefore, there is an urgent need to pre-treat laying hen meat to increase its added value and improve the quality of laying hen meat. The key here lies in the development of laying hen meat tenderization technology.

[0003] Meat tenderization is to refine or break myofibril proteins to reduce their shear force. At present, most methods use tenderizers to tenderize non-laying chickens, such as inorganic salts or proteases, which belong to chemical or biological tenderization methods. At present, new tenderization methods include physical tenderization methods such as ultrasound, electric field, and tumbling. In addition, there are methods that use multiple methods to synergistically tenderize.

[0004] The current research on ultrasonic tenderization focuses on the adjustment of ultrasonic parameters, and there is little research on the ultrasonic action mode, which makes it difficult for the ultrasonic tenderization process to break through the bottleneck of tenderization effect in terms of technology. At the same time, the tenderization soaking time is too long, the efficiency is low, and the ultrasound uses high power and high energy consumption. Therefore, it is very necessary and significant to provide an improved method and device for tenderizing chicken meat of eliminated laying hens. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for tenderizing the chicken of discarded laying hen. The method provided by the present invention can enhance the water retention of muscle fibers and improve the tenderness of the chicken of discarded laying hen.

[0006] The present invention provides a method for tenderizing chicken of eliminated laying hens, comprising the following steps:

[0007] The chicken breast meat of eliminated laying hens is pre-treated and then treated with a tenderizer and ultrasound to obtain the tenderizer; the tenderizer includes calcium chloride and protease; and the ultrasound is alternating dual-frequency ultrasound.

[0008] Preferably, the ultrasonic power is 120-300 W, the ultrasonic treatment temperature is 25-35° C., and the ultrasonic treatment time is 15-30 min.

[0009] Preferably, the frequency of the ultrasonic treatment is a dual frequency of alternating 22kHz and 40kHz, with no delay switching, and the switching time is every 10s.

[0010] Preferably, the concentration of calcium chloride is 1.5% to 2.5% (w / v); the concentration of protease is 1.5% to 2.5% (w / v).

[0011] Preferably, the use of a tenderizer in conjunction with ultrasonic treatment specifically comprises:

[0012] Calcium chloride is used to coordinate ultrasonic treatment for 5 to 10 minutes, and then protease is used to coordinate ultrasonic treatment for 10 to 20 minutes, and then the surface is immersed in the protease solution for a further 30 minutes.

[0013] Preferably, the pre-processing of the chicken breast meat of the eliminated laying hens includes: washing the chicken breast meat of the eliminated laying hens, removing connective tissue, fascia and fat, and cutting into pieces.

[0014] Preferably, the size of the cut pieces is 30×30×30 mm;

[0015] The sources of chicken breast meat from eliminated laying hens include: laying hens directly eliminated from poultry farms, the cold fresh meat market; or from -40 to -25°C low-temperature cold storages for livestock and poultry meat.

[0016] Preferably, the pre-processing of the chicken breast meat of the eliminated laying hens also includes placing it in a filter bag, and the mesh number of the filter bag is 200 meshes.

[0017] The present invention provides a chicken tenderizing device, comprising:

[0018] A constant temperature water bath disposed in the chicken tenderizing device;

[0019] Ultrasonic vibrators are arranged in multiple concentric circles at the bottom of the water bath.

[0020] Preferably, the multi-point concentric circle arrangement of the ultrasonic vibrators is specifically as follows: ultrasonic vibrators of different frequencies are arranged in sequence and at intervals from the center of the circle outwards.

[0021] Compared with the prior art, the present invention provides a method for tenderizing chicken, comprising the following steps: pre-treating the chicken breast of the eliminated laying hens, and then using a tenderizer to coordinate ultrasonic treatment to obtain the chicken breast; the tenderizer includes calcium chloride and protease; the ultrasound is alternating dual-frequency ultrasound. The ultrasonic device of the present invention adopts a concentric circle arrangement mode of ultrasonic vibrators, which can provide an external uninterrupted alternating dual-frequency ultrasonic physical field for the entire tenderizing process of the eliminated laying hens, and maximize the penetration of calcium chloride and protease solution into the deep layer of muscle tissue. The former calcium chloride can increase the ion strength in the muscle, improve the ion distribution, and enhance the water retention of muscle fibers; the latter protease hydrolyzes and refines the muscle fibers, disintegrates the macromolecular protein of the muscle fibers, and reduces the shear force, thereby improving the tenderness of the eliminated laying hens. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a concentric circle dual-frequency alternating ultrasonic device;

[0023] Figure 2 The ultrasonic vibrator arrangement modes (a. 3D modeling; b. concentric circle arrangement; c. matrix arrangement).

[0024] Figure 3 This is a simulation model of the acoustic field generated by the matrix-arranged vibrators within one cycle after ultrasonic excitation (A~F: ultrasonic distribution state in the medium from the initial time T0 to T6; a.~f.: acoustic field distribution state on the medium surface from the initial time T0 to T6)

[0025] Figure 4 It is a simulation model of the sound field generated by the vibrators arranged in concentric circles within one cycle after ultrasonic excitation (A~F: the distribution state of ultrasonic waves in the medium from the initial time T0 to T6; a.~f.: the distribution state of the sound field on the medium surface from the initial time T0 to T6).

[0026] Figure 5 The molecular weight distribution of myofibrillar protein in egg-laying chickens under different ultrasound powers.

[0027] Figure 6 The effect of different ultrasonic frequency treatments on the shear force of egg-laying chicken. DETAILED DESCRIPTION

[0028] The present invention provides a method and device for tenderizing chicken meat of eliminated laying hens. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve the desired effect. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they all fall within the scope of protection of the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0029] The present invention provides a method for tenderizing chicken of eliminated laying hens, comprising the following steps:

[0030] The chicken breast meat of eliminated laying hens is pre-treated and then treated with a tenderizer and ultrasound to obtain the tenderizer; the tenderizer includes calcium chloride and protease; and the ultrasound is alternating dual-frequency ultrasound.

[0031] The chicken tenderizing method provided by the present invention first provides chicken breast meat of eliminated laying hens.

[0032] Specifically, the sources of chicken breast meat from eliminated laying hens include: laying hens directly eliminated from poultry farms, the cold fresh meat market; or from -40 to -25°C low-temperature cold storage for livestock and poultry meat.

[0033] The breast meat of the discarded laying hens will then be pre-processed.

[0034] The present invention pre-processes the breast meat of discarded laying hens, including: washing the breast meat of discarded laying hens, removing connective tissue, fascia and fat, and cutting into pieces. The size of the pieces is 30×30×30 mm.

[0035] After cutting into pieces, the chicken breast meat of the eliminated laying hens is pre-processed and placed in a filter bag, and the mesh number of the filter bag is 200 meshes.

[0036] After being placed in a filter bag, a tenderizer is used in conjunction with ultrasonic treatment. The tenderizer includes calcium chloride and protease.

[0037] In some preferred embodiments of the present invention, the use of a tenderizer in conjunction with ultrasonic treatment is specifically:

[0038] Calcium chloride is used to coordinate ultrasonic treatment for 5 to 10 minutes, and then protease is used to coordinate ultrasonic treatment for 10 to 20 minutes, and then the mixture is immersed in the protease solution for 30 minutes. The total time is 45 to 60 minutes.

[0039] In some preferred embodiments of the present invention, the use of a tenderizer in conjunction with ultrasonic treatment is specifically:

[0040] Calcium chloride was used to coordinate ultrasonic treatment for 6 to 9 minutes, and then protease was used to coordinate ultrasonic treatment for 12 to 18 minutes, and then the surface was immersed in the protease solution for another 30 minutes.

[0041] The ultrasound of the present invention is an alternating dual-frequency ultrasound. The frequency of the ultrasound treatment is an alternating dual-frequency of 22kHz and 40kHz, with no delay switching, and the switching time is every 10s.

[0042] In some preferred embodiments of the present invention, the ultrasonic power is 120-300 W, the ultrasonic treatment temperature is 25-35° C., and the ultrasonic treatment time is 15-30 min.

[0043] In some preferred embodiments of the present invention, the ultrasonic power is 130-280 W, the ultrasonic treatment temperature is 28-35° C., and the ultrasonic treatment time is 15-28 min.

[0044] In some preferred embodiments of the present invention, the ultrasonic power is 150-260 W, the ultrasonic treatment temperature is 30-35° C., and the ultrasonic treatment time is 15-25 min.

[0045] In some preferred embodiments of the present invention, the ultrasonic power is 180-240 W, the ultrasonic treatment temperature is 32-35° C., and the ultrasonic treatment time is 15-20 min.

[0046] In certain embodiments of the present invention, the concentration of calcium chloride is 1.5% to 2.5% (w / v).

[0047] In certain embodiments of the present invention, the concentration of calcium chloride is 1.8% to 2.5% (w / v).

[0048] In certain embodiments of the present invention, the concentration of calcium chloride is 2% to 2.5% (w / v).

[0049] In certain embodiments of the present invention, the concentration of the protease is 1.5% to 2.5% (w / v).

[0050] In certain embodiments of the present invention, the concentration of the protease is 1.8% to 2.5% (w / v).

[0051] In certain embodiments of the present invention, the concentration of the protease is 2% to 2.5% (w / v).

[0052] The calcium chloride tenderizer of the present invention can increase the ion strength in the muscle, improve the ion distribution, and enhance the water retention of the muscle fiber; the protease tenderizer hydrolyzes and refines the muscle fiber, disintegrates the macromolecular protein of the muscle fiber, and reduces the shear force, thereby improving the tenderness of the chicken meat of the eliminated laying hen.

[0053] The present invention also provides an ultrasonic tenderizing device for discarded laying hen, comprising:

[0054] A constant temperature water bath disposed in the chicken tenderizing device;

[0055] Ultrasonic vibrators are arranged in multiple concentric circles at the bottom of a constant temperature water bath.

[0056] Figure 1 The schematic diagram of the concentric circle dual-frequency alternating ultrasonic device of the present invention is shown in the figure, 1-device housing, 2-constant temperature water bath, 3-water bath cover, 4-water bath drain, 5-22kHz ultrasonic vibrator, 6-40kHz ultrasonic vibrator.

[0057] The ultrasonic tenderizing device for chicken meat of eliminated laying hens of the present invention comprises a shell, and the shell of the device is made of 304 stainless steel. The cover plate is made of transparent acrylic material, has a thickness of 8mm, and is provided with a round handle.

[0058] The chicken tenderizing device of the present invention comprises a constant temperature water bath arranged in the chicken tenderizing device, and the total volume of the inner cavity is 8L.

[0059] In certain embodiments of the present invention, the constant temperature water bath uses electric heating tubes located on both sides for heating and temperature control, and the inner bottom diameter of the water bath is 500 mm; the water bath cover is made of acrylic material, and its edge fits the notch of the water bath; a drainage hole is left at one end of the bottom of the water bath, and the hole diameter is 12 mm;

[0060] The chicken tenderizing device of the present invention comprises ultrasonic vibrators arranged in a multi-point concentric circle manner and arranged at the bottom of a water bath.

[0061] In a preferred embodiment of the present invention, the multi-point concentric circle arrangement of ultrasonic vibrators is specifically as follows: ultrasonic vibrators of different frequencies are arranged in sequence and at intervals from the center of the circle outwards.

[0062] In one preferred embodiment of the present invention, the vibration frequency of the innermost circle of 4 and outermost circle of 8 vibrators is 22kHz, and the middle circle of 8 ultrasonic vibrators is 40kHz. When there is a break in the working of ultrasonic vibrators of one frequency, the vibrators of another frequency will continue to work without delay.

[0063] In one preferred embodiment of the present invention, 4 ultrasonic vibrators with a frequency of 22kHz are arranged at equal intervals with the center of the circular vibrator as the origin at 100mm from the bottom center of the constant temperature water bath (the vibrator diameter is 40mm, and the distance between the centers of the vibrators is 100√2mm); from the inside to the outside, 8 ultrasonic vibrators with a frequency of 40kHz are arranged at equal intervals at 250mm from the bottom center of the water bath (the vibrator diameter is 45mm, and the distance between the centers of the vibrators is 500[√(2-√2) / 2]mm); finally, 8 ultrasonic vibrators with a frequency of 22kHz are arranged at equal intervals at 400mm from the bottom center of the water bath (the vibrator diameter is 40mm, and the distance between the centers of the vibrators is 800[√(2-√2) / 2]mm). In this way, a concentric dual-frequency ultrasonic array is formed with the center of the bottom center of the water bath as the center and extending from the inside to the outside. The ultrasonic emitting surfaces of all the vibrators are adhered to the bottom of the water bath in direct contact.

[0064] When using the above device, the tenderizing method of the present invention is specifically as follows:

[0065] The chicken breast meat of eliminated laying hens is pre-treated and then subjected to ultrasonic treatment with a tenderizer in the tenderizing device to obtain the tenderizer; the tenderizer includes calcium chloride and protease; and the ultrasound is alternating dual-frequency ultrasound.

[0066] More preferably, the present invention pours the medium distilled water into the water bath of the dual-frequency ultrasonic device, and the volume of the distilled water is 2 / 3 of the total volume of the inner cavity of the water bath, and the temperature is kept constant. A beaker containing a certain volume of calcium chloride solution is placed in the center of the water bath, and a filter bag containing eliminated egg-laying chicken is placed in the beaker and allowed to stand for 15 minutes. After the temperature of the solution in the beaker remains constant, the ultrasound is turned on again, and the 22 / 40kHz dual-frequency ultrasound is used for alternating treatment without delay for 5 to 10 minutes. Subsequently, the filter bag containing the eliminated egg-laying chicken is transferred to the preheated protease solution beaker, and placed in the center of the ultrasonic water bath to continue the dual-frequency alternating ultrasonic treatment for 10 to 20 minutes. Then, the ultrasound is turned off, and the beaker containing the protease solution continues to stand in the constant temperature water bath for 30 minutes. Next, the chicken breast is taken out of the filter bag, and the tenderness of the eliminated egg-laying chicken is significantly improved by the specific ultrasonic power, ultrasonic temperature, ultrasonic time and tenderizer concentration of the present invention.

[0067] The ultrasonic device of the present invention adopts a concentric circle arrangement mode of ultrasonic vibrators, which can provide an external uninterrupted alternating dual-frequency ultrasonic physical field for the entire tenderization process of eliminated egg-laying chicken meat, thereby maximally promoting the penetration of calcium chloride and protease solution into the deep layer of muscle tissue.

[0068] The present invention mainly improves the ultrasonic generating device, adopts the concentric circle vibrator arrangement mode, and performs 22 / 40kHz dual-frequency alternating non-delay treatment. The alternating occurrence of the two frequencies significantly enhances the mass transfer effect and the dissolution-promoting effect, and the energy utilization rate is higher, which saves about 20% energy compared with the single frequency (Pan Zhongli, 2011). Various studies have also shown that the alternating dual-frequency treatment effect is better than the single frequency or synchronous dual-frequency treatment effect. Its main advantage is that the alternating generation of two ultrasonic frequencies is equivalent to the end of one type of ultrasound, and its gap is replaced by another frequency of ultrasound, which belongs to multi-target ultrasound. After the alternating dual-frequency ultrasound is combined with the calcium chloride solution for pre-tenderization, the tenderization treatment of the protease is carried out, which enhances the ion strength in the muscle tissue and improves the water retention performance. At the same time, the protease quickly penetrates into the deep tissue, hydrolyzes the macromolecular protein, reduces the shear force of the muscle fiber, and significantly improves the tenderness of the eliminated laying hen.

[0069] The present invention adopts a concentric ultrasonic generator. The chicken breast meat undergoes ultrasonic-calcium chloride and ultrasonic-protease tenderization treatments successively. The mechanical and cavitation effects of ultrasonic waves promote the efficient penetration of these two tenderizers into deep tissues, causing the muscle fiber structure to continuously change. Testing of the treated chicken breast meat shows that the shear force of the meat is significantly reduced, the tenderness is increased, and the quality indicators are also significantly improved; at the same time, the water retention of the chicken meat changes less. The shorter ultrasonic treatment time significantly improves the original characteristics of the eliminated laying hen meat, such as coarse muscle fibers, old meat, and average water retention and taste, expands its potential market application prospects, and enhances the economic value of eliminated laying hen meat.

[0070] The ultrasonic device used in the method of the present invention has a simple structure and good heat preservation effect. After computer simulation modeling, the results show that compared with the arrangement of traditional matrix ultrasonic vibrators ( Figure 2 c.), concentric circle arrangement ( Figure 2 b.) The ultrasonic sound field generated is more uniform and has a higher sound field density, which has a stronger effect on tenderizing chicken. Specifically, the ultrasonic field generated by the matrix ultrasonic vibrator arrangement is more dispersed in one cycle, and even a vacuum zone of the sound field appears ( Figure 3 E), which seriously affects the ultrasonic tenderization effect. The ultrasonic field generated by the concentric circle arrangement is highly uniform, and no obvious sound wave peak and valley cancellation occurs in one ultrasonic cycle, and the sound field density is good ( Figure 4 E).

[0071] In addition, multiple ultrasonic vibrators arranged in concentric circles work alternately at different frequencies, ensuring that the ultrasonic field propagates evenly in the medium while fully pulling the microstructure of the muscle tissue of the eliminated laying hens. The resulting gaps combined with the ultrasonic micro-jet effect make it easier for the tenderizer solution to continuously penetrate deep into the tissue, shortening the tenderizing time and improving efficiency. It can also soften, refine and even break the muscle fibers of the eliminated laying hens at a lower ultrasonic power, reducing energy consumption.

[0072] In addition, compared with the use of a single tenderizer, the compound use of multiple tenderizers further improves the tenderizing effect of chicken. Specifically, the calcium chloride used first provides a large amount of calcium ions to the muscle tissue, enhances the muscle ion strength, improves the ion distribution, improves the solubility of myofibrillar protein, promotes the interaction of protein chains, forms a stable colloidal structure, and increases the protein hydration and water retention capacity. Then, the diffusion of proteases degrades the macromolecular myofibrillar protein, produces small molecular proteins, weakens the muscle fiber dimensions, and reduces the shear force of meat. Compared with the control group, dual-frequency alternating ultrasound successively cooperates with calcium chloride and protease tenderizers, which can significantly improve the tenderness of 55.2% of the eliminated egg-laying chicken (ultrasonic power 240W). At the same time, while retaining the water retention of chicken to the greatest extent, the texture index is also significantly reduced. The hardness, stickiness and chewiness of the eliminated egg-laying chicken meat decreased by 31.5%, 48.8% and 25.2% respectively, and the taste of the muscle tissue was improved; while its cooking loss and centrifugal loss rate only slightly increased by 5.37% and 2.74%.

[0073] The invention is easy to operate and requires low equipment investment, and can effectively solve the problems of coarse chicken fiber, poor meat quality, and bad taste of discarded laying hen meat that affect the deep processing and recycling of laying hen meat resources, and has a certain promoting effect on the economic boost of my country's laying hen breeding industry.

[0074] In order to further illustrate the present invention, a chicken tenderizing method and device provided by the present invention are described in detail below in conjunction with embodiments.

[0075] Example 1

[0076] Wash the chicken breasts of discarded laying hens, remove the surface connective tissue, fascia and fat, cut them into 30×30×30mm cubes, and put them into a 200-mesh filter bag for tenderization.

[0077] Calcium chloride and protease solid powder were weighed using an analytical balance, and a solution with a mass concentration of 2.5% (w / v) was prepared using a volumetric flask for later use.

[0078] Pour the medium distilled water into the water bath of the dual-frequency ultrasonic device, the volume of distilled water is 2 / 3 of the total volume of the water bath cavity, and keep constant temperature. Place a beaker containing a certain volume of calcium chloride solution in the center of the water bath, and put a filter bag containing eliminated laying hen in the beaker and let it stand for 15 minutes. After the temperature of the solution in the beaker remains constant, turn on the ultrasound, and use 22 / 40kHz dual-frequency ultrasound to alternately treat for 5 to 10 minutes without delay. Then, transfer the filter bag containing eliminated laying hen to the preheated protease solution beaker, place it in the center of the ultrasonic water bath and continue the dual-frequency alternating ultrasound treatment for 10 to 20 minutes. Then, turn off the ultrasound and let the beaker containing the protease solution stand in the constant temperature water bath for 30 minutes. Next, take out the chicken breast from the filter bag, and screen the ultrasonic power, ultrasonic temperature, ultrasonic time and tenderizer concentration with shear force as the evaluation index. Then the texture indexes, cooking loss and centrifugal loss rate of chicken breast meat from eliminated laying hens, as well as changes in the molecular weight of myofibrillar protein were measured.

[0079] Ultrasonic power screening:

[0080] Under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic treatment temperature of 25℃, and ultrasonic treatment time of 10min, the ultrasonic treatment power was screened, and the results are shown in Table 1. With the increase of ultrasonic power, the shear force of the eliminated laying hen meat continued to decrease, but too high power would increase the shear force. Therefore, the selection of 240W ultrasonic power for tenderization treatment can significantly reduce the shear force of muscle tissue by 38.9% compared with the control group, and the tenderness of the eliminated laying hen meat is improved.

[0081] Table 1 Screening of alternating dual-frequency ultrasonic power

[0082] Ultrasonic power / W Shear force / N 0 20.75±1.63 120 18.68±2.42 180 16.25±1.09 240 12.67±1.05* 300 17.78±2.34

[0083] Note: "*" indicates that the data in the same column are significantly different, p < 0.05. The same below.

[0084] Example 2

[0085] Ultrasonic temperature screening:

[0086] The method is the same as that in Example 1, except that the ultrasonic treatment temperature was screened under the conditions of ultrasonic alternating frequency of 22 / 40 kHz, ultrasonic power of 240 W, and ultrasonic treatment time of 10 min, and the results are shown in Table 2. As the ultrasonic temperature increases, the shear force of the eliminated laying hen is also continuously reduced, reaching a valley value at 35°C. Therefore, 35°C is selected as the optimal ultrasonic treatment temperature.

[0087] Table 2 Screening of ultrasonic treatment temperature

[0088] Ultrasonic temperature / ℃ Shear force / N 25 17.51±2.31 30 13.74±2.13 35 12.28±2.52*

[0089] Embodiment 3:

[0090] Selection of ultrasonic treatment time:

[0091] The method of Example 1 is different in that the ultrasonic treatment time is screened under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic power of 240W, and ultrasonic treatment temperature of 35°C. The results are shown in Table 3. A relatively low value of shear force can be achieved with a treatment time of 15min. Continuing to increase the ultrasonic treatment time will not only not continue to reduce the shear force of the muscle, but will increase it continuously. It can be seen that long-term ultrasonic treatment is not conducive to the tissue shear force of eliminated laying hen, affecting the final tenderness. A shorter treatment time of 15min can be selected.

[0092] Table 3 Screening of ultrasonic treatment temperature

[0093] Ultrasonic time / min Shear force / N 15 15.13±0.65* 20 17.28±2.30 25 18.10±1.04

[0094] Example 4

[0095] Screening of tenderizer concentration:

[0096] The method is the same as that of Example 1, except that the concentration of the tenderizer is screened under the conditions of ultrasonic alternating frequency of 22 / 40 kHz, ultrasonic power of 240 W, ultrasonic treatment temperature of 35° C., and ultrasonic treatment time of 15 min, and the results are shown in Table 4. Compared with 1.5% and 2.0%, the tenderizer concentration of 2.5% can significantly improve the tenderness of muscle tissue.

[0097] Table 4 Screening of tenderizer concentration

[0098] Calcium chloride / % Shear force / N Protease / % Shear force / N 1.5 15.35±0.81 1.5 15.45±4.24 2.0 11.75±2.43 2.0 12.65±2.66 2.5 11.55±0.76* 2.5 9.43±1.11*

[0099] Embodiment 5:

[0100] Ultrasonic treatment time distribution when two tenderizers are used together:

[0101] Under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic power of 240W, and ultrasonic treatment temperature of 35℃, the ultrasonic treatment time when the two tenderizers are used together is allocated. First, it is treated with calcium chloride for 5 to 10 minutes, and then treated with protease for 10 to 20 minutes. Subsequently, it continues to be immersed in the latter protease solution for 30 minutes. The test results are shown in Table 5. Ultrasonic-calcium chloride and ultrasonic-protease treatment can significantly reduce the shear force of chicken breast tissue of eliminated laying hens, and the tenderness continues to increase. Among them, when the ultrasonic-calcium chloride treatment is 10 minutes, the ultrasonic-protease treatment is 15 minutes. Under this time organization, the shear force of muscle tissue is reduced to 9.28±1.73N, and the tenderness is the highest. Compared with the original chicken breast of 20.75±1.63N, the tenderness is significantly increased by 55.3%, more than doubled.

[0102] Table 5 Ultrasonic time distribution when two tenderizers are used together

[0103]

[0104] Embodiment 6:

[0105] Texture index and water retention:

[0106] Under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic power of 120W, and ultrasonic treatment temperature of 35℃, ultrasonic synergistic 2.5% calcium chloride treatment for 10 minutes, ultrasonic synergistic 2.5% protease treatment for 15 minutes, and then continued to soak in protease solution for 30 minutes. Compared with the control group, the hardness, stickiness and chewiness of the eliminated egg-laying chicken meat decreased by 26.5%, 49.3% and 21.9% respectively; the cooking loss rate and centrifugal loss rate increased by 1.15% and 3.41%.

[0107] Embodiment 7:

[0108] Texture index and water retention:

[0109] Under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic power of 180W, and ultrasonic treatment temperature of 35℃, ultrasonic synergistic 2.5% calcium chloride treatment for 10 minutes, ultrasonic synergistic 2.5% protease treatment for 15 minutes, and then continued to soak in protease solution for 30 minutes. Compared with the control group, the hardness, stickiness and chewiness of the eliminated egg-laying chicken meat decreased by 29.5%, 41.7% and 16.0% respectively; the cooking loss rate and centrifugal loss rate increased by 0.34% and 2.86%.

[0110] Embodiment 8:

[0111] Texture index and water retention:

[0112] Under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic power of 240W, and ultrasonic treatment temperature of 35℃, ultrasonic synergistic 2.5% calcium chloride treatment for 10 minutes, ultrasonic synergistic 2.5% protease treatment for 15 minutes, and then continued to soak in protease solution for 30 minutes. Compared with the control group, the hardness, stickiness and chewiness of the eliminated egg-laying chicken meat decreased by 31.5%, 48.8% and 25.2% respectively; the cooking loss rate and centrifugal loss rate increased by 5.37% and 2.74%.

[0113] Embodiment 9:

[0114] Texture index and water retention:

[0115] Under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic power of 300W, and ultrasonic treatment temperature of 35℃, ultrasonic synergistic 2.5% calcium chloride treatment for 10 minutes, ultrasonic synergistic 2.5% protease treatment for 15 minutes, and then continued to soak in protease solution for 30 minutes. Compared with the control group, the hardness, stickiness and chewiness of the eliminated egg-laying chicken meat decreased by 29.6%, 45.5% and 31.0% respectively; the cooking loss rate and centrifugal loss rate increased by 8.89% and 4.12%.

[0116] Embodiment 10:

[0117] Myofibrillar protein molecular weight distribution:

[0118] Under the conditions of ultrasonic alternating frequency of 22 / 40kHz, ultrasonic power of 120-300W, and ultrasonic treatment temperature of 35℃, ultrasonic assisted 2.5% calcium chloride treatment for 10min, ultrasonic assisted 2.5% protease treatment for 15min, and then continued to be immersed in the protease solution for 30min. The molecular weight distribution of myofibrillar protein is as follows Figure 5 As shown ( Figure 5 , the molecular weight distribution of myofibrillar proteins in eliminated laying hen meat under different ultrasonic powers). With the increase of ultrasonic power, the myosin heavy chain around 116.0 kDa was continuously degraded, and the myosin light chain and troponin with medium and low molecular weight around 25-45 kDa increased. This shows that the alternating dual-frequency ultrasound degraded the myofibrillar large molecular weight proteins in eliminated laying hen meat, effectively reduced the shear force of muscle fibers, and significantly improved the tenderness.

[0119] Embodiment 11:

[0120] Acoustic field simulation model establishment:

[0121] Comsol simulation software was used to simulate the acoustic field of the ultrasonic device. The geometric modeling parameters used are shown in Table 6.

[0122] Table 6 Geometric parameters of 3D modeling of ultrasonic device

[0123] name expression value describe f0 22[kHz] 22000Hz 22kHz frequency f01 40[kHz] 40000Hz 40kHz frequency c0 1497[m / s] 1497m / s Sound speed in water t0 1 / f0 4.5455E-5s The propagation time of one sound wave is 1 t01 1 / f01 2.5E-5s The propagation time of one sound wave is 2 lmd0 c0 / f0 0.068045m Wavelength 1 lmd01 c0 / f01 0.037425m Wavelength 2 hmax lmd0 / 6 0.011341m Maximum grid size Tmax 500e-3[m] / c0 2.672E-4s The time it takes for the sound waves to travel through the container n Tmax / T0 5.739 The number of cycles it takes to traverse the container

[0124] Table 6 shows that the concentric circle and matrix ultrasonic device models were established using 1 / 6 of the wavelength of 22kHz ultrasound in medium water as the maximum grid size ( Figure 2 , Schematic diagram of concentric double-frequency alternating ultrasonic device). The equipment shell and medium materials are selected from the "material module" of the software "Stainless steel" and "Water, liquid" respectively. The model uses Gaussian pulse function (gp1(t) = e^(-t 2 / 2σ 2 ) / σ(2π)^0.5) as the basic signal, and the acoustic wave analytical equation (an(t)=1e^-6*gp1(t)*sin(2*π*f0*t)) as the acoustic wave excitation equation to simulate the acoustic field, which lasts for a sound field propagation process (T0~T6). Among them, T0=0s, T6=6.9091E-4s, and a real-time image is captured at equal intervals. The simulation results of the acoustic field propagation process are as follows Figure 3 ( Figure 3 , a simulation model of the acoustic field generated by the vibrators arranged in a matrix within one cycle after ultrasonic excitation) and Figure 4 ( Figure 4 , as shown in the simulation model of the sound field generated by the vibrators arranged in concentric circles within one cycle after ultrasonic excitation).

[0125] The results of the above embodiments show that, in the process of 22kHz / 40kHz dual-frequency ultrasonic alternating treatment, when the ultrasonic power is 120-240W, the ultrasonic temperature is 25-35°C, the ultrasonic-calcium chloride treatment is 5-10min, and the ultrasonic-protease treatment is 10-20min, the shear force of the chicken breast meat of the eliminated laying hens is significantly reduced by 15.6%-55.2%, the hardness is reduced by 26.5%-29.6%, the viscosity is reduced by 41.7%-49.3%, the chewiness is reduced by 16.0%-31.0%, the cooking loss rate is increased by 0.34%-8.89%, and the centrifugal loss rate is increased by 2.74-4.12%. Although the use of ultrasound combined with a composite tenderizer slightly increased the cooking loss and centrifugal loss rate of chicken compared to the control group, this method obviously effectively improved the tenderness of the eliminated egg-laying chicken, while also reducing the hardness, stickiness and chewiness of the meat, significantly improving the original "old" and "woody" taste of the eliminated egg-laying chicken. The visualization results simulated by the 3D sound field simulation model also proved that the concentric circle ultrasonic vibrator arrangement method is better than the traditional matrix ultrasonic vibrator arrangement method. The former produces a more uniform sound field and a higher sound field density, and has a stronger effect on the tenderization of eliminated egg-laying chicken.

[0126] Comparative Example 1:

[0127] Comparison between matrix ultrasonic generator and concentric ultrasonic generator:

[0128] Under the above-mentioned optimal ultrasonic treatment conditions, the ultrasonic vibrators arranged in a traditional matrix are used as the ultrasonic generator. The detailed parameters of the vibrator arrangement are as follows: Step 1, with the center of the bottom circle of the constant temperature water bath as the origin, at the radius of -300mm, -100mm, 100mm and 300mm ( Figure 2 c) Arrange ultrasonic vibrators with a diameter of 40mm and a frequency of 22kHz. The second step is to arrange 8 ultrasonic vibrators with a diameter of 45mm and a frequency of 40kHz in the vertical direction of the center of the four initial ultrasonic vibrators, with a spacing of 150mm on both sides. The third step is to arrange 8 ultrasonic vibrators with a diameter of 40mm and a frequency of 22kHz in the vertical direction of the center of the four initial ultrasonic vibrators, with a spacing of 300mm on both sides. Finally, a matrix arrangement of 22 / 40kHz ultrasonic vibrators is formed.

[0129] During the test, as the ultrasonic power continued to increase (120-240W), the shear force of the eliminated egg-laying chicken also decreased, but its tenderization effect was far less than that of the ultrasonic generator with a concentric ultrasonic vibrator arrangement. Finally, at 240W, the shear force of the eliminated egg-laying chicken was 16.75N. Compared with the concentric arrangement, the matrix ultrasonic treatment results in high shear force and low meat tenderness. Its tenderness is 32.2% lower than that of the eliminated chicken treated with the concentric ultrasonic generator.

[0130] This result confirms the result of 3D acoustic field simulation modeling, that is, after the matrix ultrasonic device performs 22 / 40kHz dual-frequency ultrasonic alternating excitation, it may cause the peak and valley of the acoustic field to cancel each other, resulting in the appearance of an acoustic field vacuum zone ( Figure 3 E), the density of the ultrasonic field is significantly reduced and the treatment effect is poor, which ultimately leads to a decrease in the tenderizing effect on eliminated laying hen chickens.

[0131] Table 7 Comparison of the effects of concentric circle ultrasonic generator (A) and matrix ultrasonic generator (B) on the tenderization of chicken meat of eliminated laying hen.

[0132] Ultrasonic power / W Shear force (A) / N Shear force (B) / N 120 18.68±2.42 19.52±1.74 180 16.25±1.09 17.69±1.31 240 12.67±1.05 16.75±0.83*

[0133] Note: “*” indicates that the data in the same row are significantly different, p < 0.05.

[0134] Comparative Example 2:

[0135] Comparison of single-frequency and dual-frequency alternation duration:

[0136] The test was conducted using an ultrasonic treatment device arranged in concentric circles, and the same parameters as in Examples 1 to 11 were used: ultrasonic power 240 W, ultrasonic temperature 35° C., ultrasonic treatment in 2.5% calcium chloride and 2.5% protease solution for 10 min and 15 min, respectively. The difference from Examples 1 to 11 was that the frequency was changed to single frequency 22 kHz treatment, single frequency 40 kHz treatment, 22 / 40 kHz alternating treatment for 10 s, 22 / 40 kHz alternating treatment for 20 s, and 22 / 40 kHz alternating treatment for 30 s ( Figure 6 , the effect of different ultrasonic frequency treatment methods on the shear force of eliminated laying hen meat). The results showed that the shear force of eliminated laying hen meat after 22 / 40kHz dual-frequency alternating treatment for 10s, 20s and 30s was 9.28N, 12.13N and 13.36N respectively, which were all lower than those after single-frequency ultrasonic treatment. Among them, the shear force of chicken meat was the lowest when 10s alternating was used, while the shear force results obtained by 20s alternating, 30s alternating and single-frequency ultrasonic treatment were all higher than that of the 10s alternating group, which indicates that the shear force of chicken meat was lower and the tenderness was higher after 22 / 40kHz dual-frequency 10s alternating treatment.

[0137] Although the results of 22kHz single-frequency treatment were not statistically significantly different from those of 10s alternating treatment, the cooking loss rate of the former (26.93%) was higher than that of the latter (22.43%), so 10s alternating treatment was still selected.

[0138] Comparative Example 3:

[0139] Comparison of the effects of 360-480W ultrasonic power and 120-240W ultrasonic power on shear force of eliminated laying hen:

[0140] The test was conducted with an ultrasonic treatment device arranged in concentric circles, and the test conditions were the same as the parameters in Examples 1 to 11. The difference was that the ultrasonic powers used were 360W, 420W and 480W. The results showed that when the ultrasonic power continued to increase to more than 300W, the shear force of the chicken would continue to increase with the increase of the ultrasonic power, and it had risen back to 17.86N at 480W, and the tenderness of the chicken decreased. This may be due to excessive loss of muscle water caused by excessive power. Therefore, the ultrasonic treatment power should not be too high.

[0141] Table 8 Effect of 360-480W ultrasonic power on tenderization of chicken meat in eliminated laying hen (A is the tenderization result under the best ultrasonic parameter of 120-240W in Examples 1-11; B is the tenderization result under this power parameter)

[0142] Ultrasonic power / W Shear force (A) / N Ultrasonic power / W Shear force (B) / N 120 18.68±2.42 360 15.11±2.08 180 16.25±1.09 420 15.94±1.67 240 12.67±1.05 480 17.86±0.22

[0143] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for tenderizing chicken meat with alternating dual-frequency ultrasound, characterized in that: The steps include: The chicken breast meat of eliminated laying hens is pre-treated and then treated with a tenderizer and ultrasound to obtain the tenderizer; the tenderizer includes calcium chloride and protease; and the ultrasound is alternating dual-frequency ultrasound; The ultrasonic power is 120-300 W, the ultrasonic treatment temperature is 25-35 °C, and the ultrasonic treatment time is 15-30 min; The concentration of the calcium chloride is 1.5% to 2.5% (w / v); the concentration of the protease is 1.5% to 2.5% (w / v); The ultrasonic treatment using a tenderizer is specifically as follows: Ultrasonic treatment with calcium chloride for 5-10 min, ultrasonic treatment with protease for 10-20 min, and then soaking in protease for 30 min; The frequency of the ultrasonic treatment is 22 kHz and 40 kHz alternating dual frequencies, with no delay switching, and the switching time is every 10 s; In the ultrasonic step, the ultrasonic vibrators are arranged in a multi-point concentric circle manner; specifically, ultrasonic vibrators of different frequencies are arranged in sequence from the center of the circle to the outside.

2. The method according to claim 1, characterized in that The pre-treatment of the chicken breast meat of the eliminated laying hens includes: washing the chicken breast meat of the eliminated laying hens, removing connective tissue, fascia and fat, and cutting into pieces.

3. The method according to claim 2, characterized in that The size of the cut piece is 30 × 30 × 30 mm; The sources of the chicken breast meat from the eliminated laying hens include: laying hens directly eliminated from poultry farms, the cold fresh meat market; or from -40 ~ -25 ℃ low-temperature cold storage for livestock and poultry meat.

4. The method according to claim 3, characterized in that The method further comprises placing the chicken breast meat of the eliminated laying hens in a filter bag after pre-processing, wherein the filter bag has a mesh number of 200.

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