Chilled fresh poultry meat processing method for improving quality of raw meat

Abstract

The invention relates to the technical field of poultry meat processing, in particular to a chilled fresh poultry meat processing method for improving the quality of raw material meat. The method comprises the following steps: carrying out radio frequency heating treatment on poultry meat, and then carrying out air cooling until the geometric center temperature of the poultry meat reaches 10 DEG C or below; the distance between the polar plates subjected to radio frequency heating treatment is 70-80mm, and the temperature is 45-60 DEG C. The method is simple and easy for large-area popularization and application; the poultry meat is processed by adopting the method disclosed by the invention, so that the elasticity and toughness of the raw material meat can be furthest maintained, and the shelf life of the chilled fresh poultry meat can be prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of poultry meat processing, and in particular to a method for processing fresh poultry meat for improving the quality of raw meat. Background Art

[0002] With the implementation of the policy of banning the sale of live poultry, fresh poultry and frozen poultry have become the future development direction. However, fresh poultry currently has a prominent problem that its quality is significantly reduced after refrigeration. Compared with freshly slaughtered chickens, its meat is loose, toughness and elasticity are reduced, which seriously affects consumers' taste experience and restricts the development of fresh poultry. The production of fresh poultry in my country mainly draws on the production process of Western white-feathered broilers, that is, stunning before slaughter, blood draining, scalding and depilation, gutting, disinfection, pre-cooling, and grading packaging. The chicken is quickly cooled to 0-4℃ after slaughter, and is always kept at 0-4℃ in subsequent circulation and sales. The chicken that has undergone this processing process has undergone an acid-discharging process, and the endogenous enzymes in the muscle still maintain a high activity, which causes the degradation of myofibrillar protein, the destruction of muscle structure, and the tenderness of the muscle. However, this raw material is more suitable for Western fast food cooking such as frying, roasting and deep-frying, while Chinese cooking requires firm and chewy meat. How to maximize the elasticity and toughness of raw meat so that it has the same quality as freshly slaughtered chickens is an urgent problem that needs to be solved in the chilled chicken industry. Summary of the invention

[0003] Based on the above content, the present invention provides a method for processing fresh poultry meat for improving the quality of raw meat. The method of the present invention can maintain the elasticity and toughness of the raw meat to the maximum extent.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a method for processing fresh poultry meat for improving the quality of raw meat, comprising the following steps:

[0006] The poultry meat is subjected to radio frequency heating treatment and then air-cooled until the geometric center temperature of the poultry meat reaches below 10°C;

[0007] The plate spacing during the radio frequency heating treatment is 70-80 mm, and the temperature is 45-60°C.

[0008] In a preferred embodiment of the present invention, the anode-to-grid ratio of the radio frequency heating treatment is 4-7, and the maximum power is 4kw.

[0009] In a preferred embodiment of the present invention, the poultry meat is subjected to radio frequency heating treatment until the geometric center temperature of the poultry meat reaches 45-60°C.

[0010] In a preferred embodiment of the present invention, the poultry meat is cleaned and drained before being subjected to radio frequency heating treatment.

[0011] In a preferred embodiment of the present invention, after air-cooling until the geometric center temperature of the poultry meat reaches below 10°C, the process further comprises the steps of packaging as required and storing at 4°C.

[0012] In a preferred embodiment of the present invention, the poultry meat is obtained by stunning, slaughtering, bleeding, depilating, disemboweling, and automatically showering the poultry, and then dividing, skinning, deboning, shaping, and cutting the obtained poultry meat carcasses.

[0013] The present invention also provides fresh poultry meat prepared according to the above-mentioned fresh poultry meat processing method for improving the quality of raw meat.

[0014] The present invention discloses the following technical effects:

[0015] The method of the invention is simple and easy to be widely promoted and applied; the method of the invention is used to process poultry meat, which can maintain the elasticity and toughness of the raw meat to the maximum extent and prolong the shelf life of the fresh poultry meat. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a schematic diagram of radio frequency heating treatment of the present invention.

[0018] Figure 2 This is the effect of the radio frequency heating treatment of the present invention on the MFI value of chicken breast.

[0019] Figure 3 This is the effect of the radio frequency heating treatment of the present invention on the TBARS value of chicken breast.

[0020] Figure 4 The effect of radio frequency heating treatment on the total bacterial count (TVC) of chicken breast meat. DETAILED DESCRIPTION

[0021] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0022] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0023] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0024] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0025] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0026] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0027] The radio frequency heating device used in the embodiment of the present invention is a fixed radio frequency heating machine (Jiyuan Radio Frequency, GJG-6B-27Ⅱ-JY).

[0028] Radio frequency is a high-frequency alternating electromagnetic wave with a frequency range of 10Hz-300MHz. The radio frequency heating system consists of a parallel plate capacitor composed of upper and lower plates. The heated material is placed between the two plates to form an alternating electromagnetic field with a frequency of 10-40MHz and a voltage of more than 5kV. This electromagnetic field penetrates the material, causing the polarization movement of polar molecules in the material and the oscillation migration of ions to generate heat, causing the material to heat up rapidly from the inside out. Compared with microwave heating, the penetration depth of radio frequency is dozens of times that of microwaves. At the same time, during radio frequency heating, the material does not need to contact the surface of the heat conductor, thereby avoiding the coking phenomenon caused by excessive local temperature of the material, and has good heating uniformity. Therefore, radio frequency processing technology is a potential high-efficiency and green processing technology.

[0029] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0030] Example 1

[0031] This embodiment provides a method for processing fresh poultry meat to improve the quality of raw meat, and the steps are as follows:

[0032] (1) After passing the inspection and quarantine, the broiler chickens are stunned, slaughtered, bled, plucked, gutted, and automatically showered;

[0033] (2) Cutting, skinning, deboning, shaping and cutting chicken carcasses;

[0034] (3) cleaning and draining the cut chicken, and placing it in a radio frequency heating device for treatment;

[0035] (4) rapidly cooling the processed chicken to a temperature below 10°C at its geometric center;

[0036] (5) Package the cooled chicken as needed and store at 4°C.

[0037] Based on Example 1, the effects of different RF heating parameters on chicken texture and cooking loss were verified:

[0038] The chicken breast sample was placed between the two plates of the RF heating equipment, with an anode-to-gate ratio of 4-7 and a maximum power of 4kw. The fiber optic temperature probe was placed in the center of the chicken breast, and the heating temperature was set to 55°C (i.e., the RF heating was stopped when the geometric center temperature of the chicken breast reached 55°C). The plate spacing was set to 70mm, 75mm, and 80mm respectively. The chicken breast treated with RF heating was first quickly air-cooled to make its geometric center temperature below 10°C, and then stored at 4°C for 3 days to measure the texture and cooking loss of the chicken breast at different RF heating temperatures.

[0039] Determination of cooking loss: accurately weigh the meat and put it into a sealed bag. Insert an insertion thermometer into the geometric center of the sample, seal the bag and put it into a constant temperature water bath at 80℃. When the center temperature of the meat reaches 75℃, immediately take out the meat sample, cool it in ice water, wipe off the juice on the surface of the meat sample with filter paper and weigh it accurately. The cooking loss is calculated as (weight before cooking - weight after cooking) / weight before cooking × 100.

[0040] Determination of shear force: Take the above-mentioned meat samples after steaming and cut into two pieces of 1cm×1cm×4cm meat strips along the muscle fiber direction for use. Use a tenderizer to cut the meat strips and measure the maximum shear force value (peak value) during the cutting process.

[0041] Texture determination: The texture of the processed meat samples was determined using a texture analyzer. The meat samples were cut into 2cm×2cm×1cm cuboids. TPA was determined using a P / 50 probe. The test parameters were pre-test speed 1mm / s, test speed 2mm / s, post-test speed 1mm / s, test speed 5mm / s, compression ratio 50%, minimum starting force 5g, and 3 parallel runs for each sample.

[0042] The effects of different plate spacings on meat texture are shown in Table 1. Shear force, hardness and chewiness are the highest when the plate spacing is 70 mm. There is no significant difference in shear force and hardness compared with 75 mm, but chewiness is significantly higher than 75 mm. The effects of different plate spacings on meat cooking loss are shown in Table 2. When the plate spacing is 70 mm, the cooking loss of chicken is also significantly higher than that of 75 mm and 80 mm. When the plate spacing is 70 mm, chicken can maintain greater toughness and shear force, so the subsequent experiments use a plate spacing of 70 mm.

[0043] Table 1 Effect of different plate spacing on shear force and texture of meat

[0044] Shear force(N) Hardness(N) Cohesion (%) Elasticity(mm) Adhesion(N) Chewability (N) 70mm 3.43±0.78ab 41.96±4.68a 0.52±0.05a 4.89±0.36a 22.87±8.31a 109.77±10.60a 75mm 2.93±0.23bc 41.22±1.83a 0.49±0.02a 4.68±0.32a 18.90±2.00a 91.59±6.36b 80mm 2.41±0.13c 35.12±1.90b 0.50±0.03a 4.35±0.39a 22.27±2.57a 90.76±5.15b

[0045] Table 2 Effect of different plate spacing on meat cooking loss

[0046] Cooking loss (%) 70mm 16.23±0.63a 75mm 13.87±0.77b 80mm 11.04±0.42c

[0047] The chicken breast sample was placed between the two plates of the RF heating equipment, with a plate spacing of 70 mm, a positive-to-grid ratio of 4-7, and a maximum power of 4 kW. The fiber optic temperature probe was placed in the center of the chicken breast, and the heating temperatures were set to 50°C, 55°C, and 60°C. The chicken breast treated with RF heating was quickly air-cooled to a geometric center temperature below 10°C, and then stored at 4°C for 3 days. The texture and cooking loss of the chicken breast at different RF heating temperatures were measured, and the results are shown in Tables 3 and 4.

[0048] Table 3 Effects of different RF heating temperatures on shear force and texture of meat

[0049]

[0050] Table 4 Effect of different RF heating temperatures on meat cooking loss

[0051]

[0052]

[0053] As shown in Table 3, the shear force, hardness, elasticity, adhesiveness and chewiness of chicken increased with the increase of heating temperature, but when the heating temperature increased to 60℃, the shear force decreased significantly (P<0.05), and the hardness, elasticity, adhesiveness and chewiness also decreased, but the difference was not significant compared with 55℃. There was no significant difference in shear force and texture between the heating temperature of 50℃ and 55℃, indicating that the RF heating temperature at 50-55℃ can maintain the texture and toughness of chicken and maintain the original quality of chicken to the greatest extent. Cooking loss refers to the percentage of water loss in meat during cooking, reflecting the water holding capacity of meat. As shown in Table 4, the cooking loss of chicken is the highest when the heating temperature is 50℃, followed by 55℃, and then 45℃ and 60℃. Considering that chicken loses more water when the heating temperature is 50℃, the optimal RF heating temperature is selected as 55℃.

[0054] The chicken breast sample was placed between the two plates of the radio frequency heating equipment, with an anode-to-gate ratio of 4-7 and a maximum power of 4kw. The fiber optic temperature probe was placed in the center of the chicken breast, the heating temperature was set to 55°C, and the distance between the plates was 70mm. The chicken breast treated with radio frequency heating was quickly air-cooled to make its geometric center temperature below 10°C, and then stored at 4°C for 5 days. The myofibrillar fragmentation index (MFI), degree of oxidation (TBARS) and total bacterial count (TVC) of the chicken breast were measured and compared with the chicken breast not treated with radio frequency heating (control group).

[0055] Myofibril fragmentation index: Weigh 1 g of minced meat sample, add 15 mL of precooled (4°C) myofibril fragmentation index buffer (100 mmol / L KCL, 11.2 mmol / L K2HPO4, 8.8 mmol / L KH2PO4, 1 mmol / L EGTA, 1 mmol / LMgCl2; i.e., MFI buffer), homogenize in an ice bath (12000 r / min, 40 s, 10 s each time, with an interval of 10 s in between), centrifuge after homogenization (1000 g, 15 min, 2°C) and discard the supernatant, add 15 mL of precooled MFI buffer again to fully suspend the precipitate, centrifuge again (1000 g, 15 min, 2°C) and discard the supernatant; after the precipitate is fully suspended with 2.5 mL of precooled MFI buffer, filter with filter cloth to remove connective tissue, rinse the centrifuge tube with 2.5 mL of precooled MFI buffer and filter, combine the filtrates to obtain a myofibrillar protein suspension. The protein mass concentration was determined by the BCA method. After adjusting the protein mass concentration to 0.5 mg / mL, the absorbance was measured at a wavelength of 562 nm using an enzyme reader. The result was multiplied by 200 to obtain the MFI value.

[0056] Determination of lipid oxidation degree: Add 2g chicken breast and 18mL 7.5% trichloroacetic acid solution to a 50mL centrifuge tube, homogenize at 10000rpm for 30s, filter with filter paper, take 2mL homogenate, add 2mL 0.02mM thiobarbituric acid (TBA), vortex for 30s, water bath at 95℃ for 30min, centrifuge at 10000r / min for 5min after cooling, and record the absorbance at 532nm. Prepare a standard curve with 1,1,3,3-tetraethoxypropane (TEP), and obtain the content value of malondialdehyde (MDA) according to the standard curve.

[0057] Determination of total colony count: Weigh 10g of chicken breast sample and place it in a homogenizing bag containing 90mL of sterile saline, and beat it with a slapping homogenizer for 2 minutes. Take 1mL of sample homogenate to prepare sample dilutions of different multiples, select 1-3 sample homogenates with appropriate dilutions, draw 1mL into a sterile culture dish, pour the cooled plate count medium into the culture dish, and rotate the culture dish to mix it evenly. After the agar solidifies, culture it at 37℃ for 48h, and record the dilution multiple and the corresponding colony count.

[0058] Figure 2 The changes in myofibril fragmentation index of chicken breast in the control group and the radiofrequency heating treatment group (referred to as the treatment group) during 5 days of refrigeration are shown. MFI reflects the degree of destruction of the myofibril structure of muscle cells and the degradation of proteins. The larger the MFI, the greater the destruction of the myofibril structure and the more tender the meat. On day 0, the MFI of the treatment group was significantly higher than that of the control group (P<0.05), but on the 4th day of storage, the MFI of the control group began to be higher than that of the treatment group. On the 5th day, the MFI of the control group was significantly higher than that of the treatment group (P<0.05), indicating that the radiofrequency heating treatment of chicken breast can reduce the degree of degradation of myofibrillar protein during storage, maintain the integrity of the myofibril structure and the toughness of the muscle.

[0059] Figure 3 The figure shows the fat oxidation of chicken breasts in the control group and the RF heating treatment group during 5 days of refrigeration. The peroxidation reaction of fat in meat products will produce a large amount of peroxides, free radicals, aldehydes and ketones, which will not only cause the product to become rancid and the quality to decline, but also bring potential harm to the food safety of consumers. Figure 3 It can be seen that within 2 days of storage, the TBARS of the treatment group was significantly higher than that of the control group. However, when the storage time reached 4 days, the TBARS of the treatment group was significantly lower than that of the control group (P<0.05), and with the increase of storage time, the increase in the control group became larger and larger, indicating that radio frequency heating can significantly inhibit fat oxidation and rancidity in chicken breast during storage.

[0060] Figure 4The figure shows the changes in the total colony count of chicken breast meat in the control group and the RF heating treatment group during 5 days of refrigeration. As shown in the figure, during the 5 days of storage, the total colony count of chicken breast meat in the treatment group was lower than that in the control group. On the 5th day, the total colony counts of the treatment group and the control group were 3.29log CFU / g and 4.85log CFU / g, respectively, indicating that RF heating treatment can effectively extend the shelf life of fresh chicken breast meat.

[0061] Comparative Example 1

[0062] (1) After passing the inspection and quarantine, the broiler chickens are stunned, slaughtered, bled, plucked, gutted, and automatically showered;

[0063] (2) Cutting, skinning, deboning, shaping and cutting chicken carcasses;

[0064] (3) The cut chicken breasts were cleaned and drained, and placed in a microwave steam tunnel for heating (first microwave heating to a center temperature of 50° C., then low-temperature steam heating at 60° C. for 20 min);

[0065] (4) rapidly cooling the processed chicken breast meat to a central temperature below 10°C;

[0066] (5) Package the cooled chicken breast as needed and store at 4°C.

[0067] In this comparative example, the shear force of the chicken breast meat after storage for 3 days was 3.03N, the elasticity was 4.32mm, and the cooking loss was 15.92%; the MFI after storage for 5 days was 79.65, the TBARS was 0.13mg / kg, and the TVC was 3.52log CFU / g.

[0068] Comparative Example 2

[0069] (1) After passing the inspection and quarantine, the broiler chickens are stunned, slaughtered, bled, plucked, gutted, and automatically showered;

[0070] (2) Cutting, skinning, deboning, shaping and cutting chicken carcasses;

[0071] (3) The cut chicken breasts were cleaned and drained, and then quickly heated in a microwave at a microwave power of 150 kW until the center temperature reached 55° C.;

[0072] (4) rapidly air-cooling the chicken breast meat after the low-temperature steam treatment so that its core temperature reaches below 10° C.;

[0073] (5) Package the cooled chicken breast as needed and store at 4°C.

[0074] In this comparative example, the shear force of the chicken breast meat after storage for 3 days was 2.69N, the elasticity was 4.17mm, and the cooking loss was 11.25%; the MFI after storage for 5 days was 81.73, the TBARS was 0.14mg / kg, and the TVC was 2.04log CFU / g.

[0075] This application verifies different parameters of microwave steam combined treatment and microwave rapid heating treatment. The results show that the parameters in comparative examples 1 and 2 are the best parameters for microwave steam combined treatment and microwave rapid heating treatment, respectively. The shear force and elasticity of chicken treated with radio frequency heating are the best. The cooking loss of chicken treated with radio frequency is higher than that of the microwave treatment group, but better than the microwave steam combined treatment group. After 5 days of storage, the MFI and TBARS of the radio frequency treatment group are similar to those of the chicken treated with microwave steam combined treatment and microwave rapid heating treatment. Radio frequency heating has good penetrability and heat transfer efficiency, which can make up for the shortcomings of steam treatment and microwave treatment, such as uneven heating, decreased water retention of meat, and slow processing speed.

[0076] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for processing fresh poultry meat to improve the quality of raw meat, characterized in that: The following steps are involved: The poultry meat is subjected to radio frequency heating treatment and then air-cooled until the geometric center temperature of the poultry meat reaches below 10°C; The plate spacing during the radio frequency heating treatment is 70-80 mm, and the temperature is 45-60°C.

2. The method for processing fresh poultry meat for improving the quality of raw meat according to claim 1, characterized in that: The anode-to-grid ratio of the radio frequency heating treatment is 4-7, and the maximum power is 4kw.

3. The method for processing fresh poultry meat for improving the quality of raw meat according to claim 1, characterized in that: The poultry meat is subjected to radio frequency heating until the geometric center temperature of the poultry meat reaches 45-60°C.

4. The method for processing fresh poultry meat for improving the quality of raw meat according to claim 1, characterized in that: The steps of washing the poultry meat and draining the water are also included before the poultry meat is subjected to radio frequency heating treatment.

5. The method for processing fresh poultry meat for improving the quality of raw meat according to claim 1, characterized in that: After air-cooling until the geometric center temperature of the poultry meat reaches below 10°C, the process also includes packaging as needed and storing at 4°C.

6. The method for processing fresh poultry meat for improving the quality of raw meat according to claim 1, characterized in that: The poultry meat is prepared by stunning, slaughtering, bleeding, depilating, gutting and automatically showering the poultry, and then dividing, skinning, deboning, shaping and cutting the obtained poultry meat carcasses.

7. Chilled fresh poultry meat prepared by the method for processing chilled fresh poultry meat for improving the quality of raw meat according to any one of claims 1 to 6.

Images