Method for improving texture quality of braised pork by changing temperature and pressure in pressure cooker

Abstract

The application discloses a method for improving the texture quality of braised pork by using a pressure cooker with variable temperature and pressure, and belongs to the field of food chemistry and physical property science. The braised pork obtained by the method has moderate lean meat hardness, good juiciness, easy chewability and high overall texture acceptance. Compared with a one-stage cooking program of a commercial pressure cooker, the lean meat chewability measured by using a texture analyzer is reduced by more than 20%, the shear force is reduced by more than 9%, and the content of water not easy to flow is increased by more than 5%. The scheme is simple and standardized, and is helpful to the technological innovation and upgrading of kitchen appliances, and promotes the industrialization and intelligentization development of Chinese traditional meat products.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for improving the texture quality of braised pork by changing the temperature and pressure of the pressure cooker, belonging to the field of food chemistry and physical properties. BACKGROUND

[0002] Braised pork has a history of about 600 years. The traditional method of braised pork is to use open fire to burn and then to simmer at low heat. The braised pork prepared by this method has rich flavor, soft texture and melts in the mouth, and is rich in nutrients, which is one of the most favorite meat dishes. However, the traditional open fire heating method has many defects, such as laborious operation, difficulty in accurately controlling the temperature of the heat transfer medium water and the temperature of the food material, easy to cause energy waste, and cannot meet the increasingly fast and simple life rhythm of people. In order to promote the intelligentization, convenience and small-scale industrialization of traditional stewing meat products, intelligent cooking equipment is gradually replacing traditional open fire cooking. Since 1991, the technology of electric pressure cooker has been developed rapidly in the direction of time-saving, energy-saving, convenience and speed. At present, the electric pressure cooker has become an essential kitchen appliance in family life. However, the heating program of commercial pressure cooker is single, and the cooking temperature is too high. Although it can make the meat material quickly mature, the muscle fibers contract severely during high-pressure cooking, and a large amount of water is lost, resulting in a serious decrease in tenderness and juiciness of the finished product.

[0003] At present, the main channel to improve the tenderness of meat products is through low-temperature cooking. For example, CN114365827A discloses a cooking method for improving the flavor and texture of meat, which can avoid meat shrinkage and water loss caused by high-temperature cooking through pre-marinating and long-time low-temperature vacuum heating processes. CN113812579A discloses a three-stage low-temperature cooking method for duck meat, which improves the tenderness of duck meat. However, studies have shown that the Maillard reaction is blocked during low-temperature cooking of meat, and its flavor formation mainly depends on fat oxidation, which seriously affects the flavor profile of the finished product.

[0004] Therefore, although low-temperature cooking can improve the tenderness of meat, for the cooking of some traditional characteristic braised dishes such as braised pork, the raw material five-flavor pork contains a large amount of fat, and low-temperature cooking will undoubtedly promote the excessive oxidation of fat, limiting the formation of some characteristic flavor substances derived from the Maillard reaction. In addition, the above-mentioned low-temperature cooking method is relatively complex and time-consuming, which does not meet the demand of contemporary young consumers for the intelligentization and convenience of home cooking. It is an urgent technical problem to be solved in the current kitchen appliance industry and the industrialization process of traditional braised pork to improve the one-stage cooking program of commercial pressure cookers and improve the texture quality of braised pork. SUMMARY

[0005]

Technical problem

[0006] In view of the cooking program defects of the lean meat taste of the braised pork product cooked by the one-stage cooking of the commercial pressure cooker, the application discloses a method for improving the texture quality of braised pork by pressure cooker variable temperature and pressure cooking.

[0007]

Technical scheme

[0008] According to the formation mechanism of the texture quality of the braised pork and the dependence of the texture quality on the processing parameters, the application adopts pressure heating to make the food material quickly mature, avoids the serious rupture and collapse of the muscle tissue and the water loss caused by high-temperature long-time pressure cooking, and then adopts temperature reduction stewing to promote the formation of protein gel, effectively reduces the conversion of the non-flowing water into free water, retains more water, reduces the chewiness of the lean meat, and improves the juiciness and elasticity, so as to construct a variable temperature and pressure cooking mode of the braised pork, and the cooking temperature is as shown in the formula (I). Figure 1 The technical scheme of the application realizes the improvement of the texture quality of the braised pork, is beneficial to improving the industrial design effect of the existing commercial pressure cooker, improves the food quality cooked by the pressure cooker, realizes the technical upgrading of the kitchen appliance industry, and promotes the industrialization of the traditional characteristic livestock meat food.

[0009] The method for improving the texture quality of the braised pork by the pressure cooker variable temperature and pressure cooking comprises the following steps:

[0010] (1) cutting the pork into pork pieces, blanching the pork pieces to obtain blanched pork pieces;

[0011] (2) mixing the blanched pork pieces and water, increasing the air pressure in the pot, and heating to make the pork pieces reach a certain temperature;

[0012] (3) restoring the normal pressure in the pot and reducing the temperature, adding salt, dark soy sauce, cooking wine, and cane sugar, stewing, and collecting juice to obtain the braised pork with improved texture quality.

[0013] Further, the pork pieces in step (1) are cubes with a side length of 4-5 cm.

[0014] Further, the pork in step (1) is pork belly, lean pork, or pork ribs.

[0015] Further, the blanching operation in step (1) is that the pork pieces and water are mixed at a mass ratio of 0.5-1.5:1, and blanched at 50-60 DEG C for 20-26 min.

[0016] Further, the mass ratio of the blanched pork pieces and water in step (2) is 0.5-1.5:1.

[0017] Further, the improved pressure in step (2) is 30-70 kPa, the heating time is 20-27 min, and the temperature of the pork chunks is raised to 102-111 DEG C.

[0018] Further, the temperature in step (3) is reduced to 92-98 DEG C.

[0019] Further, the mass ratio of the blanched pork chunks to salt in step (3) is 500:4-6.

[0020] Further, the mass ratio of the blanched pork chunks to dark soy sauce in step (3) is 500:10-20.

[0021] Further, the mass ratio of the blanched pork chunks to cooking wine in step (3) is 500:40-60.

[0022] Further, the mass ratio of the blanched pork chunks to cane sugar in step (3) is 500:40-50.

[0023] Further, the stewing time in step (3) is 18-33 min.

[0024] Further, the juice collection in step (3) is heating at 100 DEG C for 5-10 min.

[0025] The method for improving the texture quality of braised pork provided by the application has an application in the field of food processing.

[0026] The braised pork prepared according to the method is provided.

[0027] The application has the following beneficial effects:

[0028] (1) Based on the formation mechanism of the texture quality of braised pork and the dependence of the texture quality on the processing parameters, the braised pork prepared by the temperature and pressure changing cooking has moderate lean meat hardness, good elasticity and juiciness, easy chewability, and good overall texture acceptance. Compared with the one-stage cooking program of a commercial pressure cooker, the lean meat chewability measured by a texture analyzer is reduced by more than 20%, the shear force is reduced by more than 9%, and the non-flowing water content is increased by more than 5%.

[0029] (2) The method for precisely controlling the temperature of food materials by using an intelligent temperature control electric pressure cooker is not only safe and healthy, but also simple to operate, meets the demand of people for intelligent cooking, is suitable for household cooking and industrial production, and the new temperature and pressure changing cooking mode helps to reform and upgrade the kitchen appliance technology. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The temperature of the braised pork of Example 1 of the application changes with time.

[0031] Table 2 Sensory texture properties of braised pork loin cooked by the inventive examples and comparative examples.

[0032] Figure 2 Hardness and chewiness of braised pork loin cooked by the inventive examples and comparative examples.

[0033] Figure 3 Shear force of braised pork loin cooked by the inventive examples and comparative examples.

[0034] Figure 4 Non-freezable water content and freezable water content of braised pork loin cooked by the inventive examples and comparative examples.

[0035] Figure 5 Protein surface hydrophobicity and total sulfhydryl content of braised pork loin cooked by Example 1 and comparative examples.

[0036] Figure 6 Microstructure of muscle fiber cross-section of braised pork loin cooked by Example 1 and comparative examples. DETAILED DESCRIPTION

[0037] The following describes preferred embodiments of the present application, and it should be understood that the embodiments are for better explaining the present application and are not intended to limit the present application.

[0038] The water used in the following examples is purified water, and the pork is commercially available pork belly; the sensory evaluation of braised pork loin cooked by different cooking modes is performed by using the quantitative descriptive sensory analysis method. The evaluation team is composed of 10 (4 males and 6 females aged 20-30 years) experienced sensory evaluation assessors, and the sensory evaluation is performed in a standard sensory evaluation room. Before the sensory analysis, the team members need to be trained for 4 times (2 hours each time), which includes the classification of the texture sensory properties of the braised pork samples and the definition of the commonly used terms by the assessors. The sensory texture properties of the braised pork loin samples include hardness, chewiness, juiciness and elasticity, and the determined reference standards are shown in Table 1. The braised pork loin is cut into 1x1x2 cm blocks and placed in transparent plastic cups, and the temperature is kept at 55°C to avoid the influence of temperature difference on the sensory properties of the samples. The sensory properties are evaluated using a 15-point scale (0-15 points, indicating from no intensity to high intensity), and each sample is repeated three times.

[0039] Table 1 Classification and evaluation criteria of sensory properties of braised pork loin

[0040]

[0041]

[0042] The hardness, chewiness and shear force value of the pork were determined by using a texture analyzer. A cylinder with a diameter of 2 cm and a height of 1 cm was cut from the lean layer of the cooked stewed pork, and the cylinder was compressed twice using a P36 probe. The test parameters were as follows: pre-test speed 2 mm / s, test speed 2 mm / s, post-test speed 5 mm / s, compression deformation 60%, trigger force 5 g. The shear mode was selected as chicken tenderness mode, and the shear test was performed along the vertical fiber direction of the sample. The test parameters were as follows: pre-test speed 1 mm / s, test speed 2 mm / s, post-test speed 10 mm / s, shear distance 10 mm, trigger force 5 g.

[0043] The water distribution of the pork was determined by low-field nuclear magnetic resonance technology. A meat piece with a size of 20 mm x 20 mm x 6 mm was cut from the center of the lean layer of the cooked stewed pork, and was placed in the center of the coil after being wrapped with raw material tape. The sample was scanned using CPMG pulse sequence, and the test parameters were set as follows: TD: 150030, TW: 3500, sampling number (NS): 2, echo number (NECH): 3000. The scanning was repeated three times. The T2 value distribution and relaxation area were inverted using T2 Fit software.

[0044] The total sulfhydryl content and surface hydrophobicity of the lean layer of the stewed pork were determined by colorimetry. 2 g of lean meat of the stewed pork was accurately weighed, and was homogenized in 20 mL of 20 mmol / L Na2HPO4 / NaH2PO4 solution (pH 7) at 4°C and 10000 rpm for 1 min. The protein concentration of the homogenate was adjusted to 2 mg / mL by using biuret reagent. 1 mL of the 2 mg / mL protein solution was mixed with 8 mL of Tris-glycine-urea buffer (0.086 mol / L Tris, 0.09 mol / L glycine, 8 mol / L urea, 4 mmol / L EDTA, pH 8), and was centrifuged at 10000 g for 15 min. 4.5 mL of the supernatant was mixed with 0.5 mL of 10 mM / L 5,5-dithio-bis-(2-nitrobenzoic acid) at 25°C for 30 min. The absorbance value of the reaction solution was determined at 412 nm using a UV spectrophotometer, and the above operation was used as a blank control using 20 mmol / L Na2HPO4 / NaH2PO4 solution (pH 7). The calculation formula of total sulfhydryl content is as follows:

[0045] Total sulfhydryl content (nmol / mg) = (A x 10) / (ε x ρ) (1)

[0046] In the formula, A represents the absorbance value of the sample, ε represents the molar extinction coefficient, and ρ represents the protein concentration.

[0047] Take 1 mL of the above 2 mg / mL protein solution and mix it with 200 μL of 1 mg / mL bromophenol blue reagent. Incubate at 25°C in the dark for 10 min, then centrifuge at 2500 g for 15 min. Dilute the supernatant 10 times and measure the absorbance at 595 nm using a UV spectrophotometer. Use 20 mmol / L Na2HPO4 / NaH2PO4 solution (pH 7) as a blank control. The formula for calculating surface hydrophobicity is shown in Equation 2:

[0048] Surface hydrophobicity (bromophenol blue binding amount: μg) = (OD1-OD2) / OD1(2)

[0049] In the formula, OD1 and OD2 represent the absorbance values ​​of the blank control and the sample, respectively.

[0050] The microstructure of cooked pork chunks was observed using an inverted fluorescence microscope and a cryo-scanning electron microscope. A 5mm × 5mm × 10mm cuboid was cut from the center of the lean meat layer of braised pork, and transverse sections of myofibrils with a thickness of 5μm were prepared using a cryostat. The sections were stained with Sirius red for 5 min, washed with distilled water to remove excess stain, and observed under a bright field microscope at 200x magnification. Separately, a 5mm × 5mm × 2mm cuboid was cut from the center of the lean meat layer, fixed with 2.5% glutaraldehyde solution for 8 h, rinsed three times with 0.1 mol / L phosphate buffer (pH 7.2), and then subjected to a gradient dehydration with 30%, 50%, 70%, 80%, 80%, and 100% ethanol solutions. After vacuum drying for 4 hours, the sections were sputter-coated with gold and observed under scanning electron microscopy at 300x and 1000x magnification.

[0051] Example 1:

[0052] Rinse fresh pork belly with 20℃ water and cut into uniform 4cm×4cm×4cm pieces. Add 500g of pork pieces to 500g of water and blanch at 60℃ for 26 minutes. Mix the blanched pork pieces with 500g of water and place in an electric pressure cooker. Increase the working pressure to 50kPa and heat for 23 minutes. Then return to normal pressure and lower the temperature to 97℃. Add 5g of salt, 15g of dark soy sauce, 50g of cooking wine, and 45g of sugar. Simmer for 31 minutes. Finally, increase the temperature to 100℃ to reduce the sauce for 8 minutes and then stop heating to obtain braised pork with improved lean meat texture.

[0053] The textural properties of lean meat in braised pork were evaluated using quantitative descriptive sensory analysis methods, and the results are shown in Table 2. The chewiness, hardness, and shear force of the lean meat were measured using a physical property analyzer, and the results are as follows: Figure 2 and Figure 3 As shown; the water state of lean meat was analyzed using a low-field nuclear magnetic resonance spectrometer, and the content of non-flowing water and free water was as follows:Figure 4 As shown; the total sulfhydryl groups and surface hydrophobicity of lean meat protein were determined by colorimetry, and the results are as follows. Figure 5 As shown; the microstructure of transverse sections of pork myofibrils was observed using an inverted fluorescence microscope and a cryo-scanning electron microscope. The microstructure images are shown below. Figure 6 As shown.

[0054] Example 2:

[0055] Rinse fresh pork belly with 20℃ water and cut into uniform 4cm×4cm×4cm pieces. Add 500g of pork pieces to 500g of water and blanch at 60℃ for 46 minutes. Mix the blanched pork pieces with 500g of water and place in an electric pressure cooker. Increase the working pressure to 70kPa and heat for 27 minutes. Then return to normal pressure and lower the temperature to 92℃. Add 5g of salt, 15g of dark soy sauce, 50g of cooking wine, and 45g of sugar. Simmer for 20 minutes. Finally, increase the temperature to 100℃ to reduce the sauce for 8 minutes and then stop heating to obtain braised pork with improved lean meat texture.

[0056] The textural properties of lean meat in braised pork were evaluated using quantitative descriptive sensory analysis methods, and the results are shown in Table 2. The chewiness, hardness, and shear force of the lean meat were measured using a physical property analyzer, and the results are as follows: Figure 2 and Figure 3 As shown; the water state of lean meat was analyzed using a low-field nuclear magnetic resonance spectrometer, and the content of non-flowing water and free water was as follows: Figure 4 As shown.

[0057] Comparative Example 1:

[0058] Rinse fresh pork belly with 20℃ water and cut into evenly sized pieces of 4cm×4cm×4cm. Add 500g of pork pieces to 500g of water and blanch at 60℃ for 46 minutes. Mix the blanched pork pieces with 1000g of water and place in a pot. Heat over an open flame for 5 minutes until the water boils, then reduce to a simmer for 60 minutes. Add 5g of salt, 15g of dark soy sauce, 50g of cooking wine, and 45g of sugar. Finally, turn up the heat to reduce the sauce for 8 minutes and then stop heating. This is the traditional open-flame braised pork belly.

[0059] Other conditions or parameters are the same as in Example 1.

[0060] Comparative Example 2:

[0061] Fresh pork belly was rinsed with 20℃ water and cut into uniform small pieces of 4cm×4cm×4cm. 500g of pork pieces were added to 500g of water and blanched at 60℃ for 46 minutes. The blanched pork pieces and 500g of water were then mixed and placed in a commercial electric pressure cooker. The working pressure inside the cooker was increased to 50kPa and heated for 30 minutes. After returning to normal pressure, the sauce was reduced at 100℃ for 8 minutes. Heating was then stopped to obtain the braised pork sample.

[0062] Other conditions or parameters are the same as in Example 1.

[0063] Test results:

[0064] Table 2. Sensory evaluation results of braised pork belly (lean meat) in the examples and comparative examples.

[0065]

[0066] Quantitative sensory analysis is the most direct and effective method for evaluating the sensory quality of food. Table 2 shows that there was no significant difference in the firmness of the braised pork belly in the examples and the comparative examples. The sensory chewiness, juiciness, and elasticity of the braised pork belly in the examples were not significantly different from those in Comparative Example 1, but the sensory chewiness was significantly lower than that in Comparative Example 2, while the sensory juiciness and elasticity were significantly higher. Example 1 had the highest overall acceptability, while Example 2 had no significant difference in overall acceptability from Comparative Example 1. Both Examples 1 and 2 had significantly higher overall acceptability than Comparative Example 2. This indicates that compared to commercial pressure cooker cooking, variable temperature and pressure cooking can significantly improve the juiciness and elasticity of braised pork belly and reduce chewiness, thereby improving its overall acceptability. Furthermore, the sensory texture properties of braised pork belly cooked using variable temperature and pressure are quite similar to those of traditional open-flame cooking, with the former even having a higher overall acceptability than the latter.

[0067] Depend on Figure 2 It can be seen that there is no significant difference in hardness between the examples and the comparative examples. However, the chewiness of the examples and Comparative Example 1 is significantly lower than that of Comparative Example 2, a result consistent with the sensory results. Shear force is an important indicator for evaluating meat tenderness; the lower the shear force, the higher the tenderness of the meat. Figure 3It can be seen that the shear force of Example 1 is the lowest, the shear force of Example 2 and Comparative Example 1 has no significant difference, and is significantly lower than that of Comparative Example 2, indicating that the variable temperature and pressure cooking mode proposed in the present application can improve the tenderness of the lean meat of the stewed pork. The results of hardness, chewiness and shear force determined by the texture analyzer above are consistent with the sensory evaluation results. Pig meat generally includes three different forms of water, namely bound water, free water and not easily flowing water. The bound water refers to water that is tightly bound by chemical bonds and proteins and cannot flow freely. The free water is water that can flow freely outside the myofibril network. The not easily flowing water is water that exists inside the myofibril network, and its flowability is between that of the bound water and the free water. During the cooking process of the stewed pork, the myofibril protein is denatured, promoting the contraction of the muscle fiber and muscle tissue, thereby promoting the conversion of the not easily flowing water in the myofibril network to free water, and further loss in the form of free water. From the results of water content in the stewed pork of Example 1 and Comparative Examples 1 and 2, it can be seen that the not easily flowing water content in Example and Comparative Example 1 is significantly higher than that of Comparative Example 2, while the free water content shows the opposite trend, indicating that the variable temperature and pressure cooking reduces the conversion of the not easily flowing water in the lean meat to free water, which is closely related to the higher juiciness of the lean meat of the stewed pork under this mode. The oxidation and aggregation of proteins are the fundamental reasons for inducing muscle fiber contraction and leading to changes in water state, reduction of water content and deterioration of texture properties. Figure 4 It can be seen that the not easily flowing water content in Example and Comparative Example 1 is significantly higher than that of Comparative Example 2, while the free water content shows the opposite trend, indicating that the variable temperature and pressure cooking reduces the conversion of the not easily flowing water in the lean meat to free water, which is closely related to the higher juiciness of the lean meat of the stewed pork under this mode. The oxidation and aggregation of proteins are the fundamental reasons for inducing muscle fiber contraction and leading to changes in water state, reduction of water content and deterioration of texture properties. The total sulfhydryl content and surface hydrophobicity of proteins are important indicators of the degree of protein oxidation and aggregation, respectively.

[0068] Example 1 as the research object, the reasons for the multi-stage cooking to improve the texture of the lean meat of the stewed pork were further analyzed from the protein and microstructure. Figure 5 It can be seen that the total sulfhydryl content of Example 1 is significantly higher than that of Comparative Examples 1 and 2, indicating that the variable temperature and pressure cooking mode reduces the oxidation of sulfhydryl to disulfide bond in the protein of the lean meat of the stewed pork compared with the traditional open fire cooking and the commercial electric pressure cooker mode, thereby helping to inhibit the formation of protein aggregates. The surface hydrophobicity of Example 1 is close to that of Comparative Example 1 and significantly higher than that of Comparative Example 2, indicating that under the multi-stage cooking mode, the protein is in a relatively unfolded state, with more hydrophobic residues exposed on the surface of the protein. The commercial pressure cooker cooking mode promotes the excessive aggregation of proteins, resulting in the hiding of hydrophobic residues in aggregates and the inability to be detected, which further proves that the variable temperature and pressure cooking helps to reduce the oxidation and aggregation of proteins. According to the results of Example 1 and Comparative Examples 1 and 2, it can be seen that the total sulfhydryl content of Example 1 is significantly higher than that of Comparative Examples 1 and 2, indicating that the variable temperature and pressure cooking mode reduces the oxidation of sulfhydryl to disulfide bond in the protein of the lean meat of the stewed pork compared with the traditional open fire cooking and the commercial electric pressure cooker mode, thereby helping to inhibit the formation of protein aggregates. Figure 6The microstructure of Example 1 and Comparative Example 1 can be known that the muscle fiber contraction of Comparative Example 2 is serious, and the gap between muscle fibers is large, while the muscle fiber contraction of Example 1 and Comparative Example 1 is reduced, and a more uniform myofibrillar gel network is formed, and such network structure is helpful for water retention. Therefore, compared with the one-stage cooking of the commercial electric pressure cooker, the variable temperature and pressure cooking mode designed by the present application effectively reduces the oxidation and aggregation of lean meat protein of the braised pork, relieves the contraction of muscle fibers, promotes the formation of myofibrillar gel network, retains more water, and thus significantly improves the chewiness, juiciness, elasticity and overall acceptability of the braised pork, and the texture quality of the braised pork obtained is close to or even better than that of traditional open fire cooking.

[0069] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be defined by the claims.

Claims

1. A method for improving the texture quality of braised meat products by changing temperature and pressure in a pressure cooker, characterized in that, It comprises the following steps: (1) Put 4-5 cm square size uniform pork belly, pork lean meat or pork chop meat pieces into an electric pressure cooker according to a weight ratio of 0.5-1.5:1 of the meat pieces and water, then blanch the pork pieces to break the fibers, to obtain blanched pork pieces; the blanching operation is to mix the pork pieces and water according to a mass ratio of 0.5-1.5:1, and blanch at 50-60℃ for 20-26 min; (2) Mix the blanched pork pieces with water, increase the pressure in the pot to 30-70 kPa, and heat for 20-27 min to raise the pork pieces to 102-111℃; (3) Restore the pressure in the pot to normal and reduce the temperature to 92-98℃, add salt, old soy sauce, cooking wine, and cane sugar, stew for 18-33 min to collect the juice, the mass ratio of the blanched pork pieces and salt is 500:4-6, the mass ratio of the blanched pork pieces and old soy sauce is 500:10-20, the mass ratio of the blanched pork pieces and cooking wine is 500:40-60, and the mass ratio of the blanched pork pieces and cane sugar is 500:40-50, to obtain red-braised pork with improved texture quality.

2. The method of claim 1, wherein, The red-braised pork with improved texture quality obtained in step (3) has moderate hardness, good juiciness, easy chewability, and high overall texture acceptance, compared with a commercial pressure cooker one-stage cooking program, the chewability of the lean meat determined by a texture analyzer is reduced by more than 20%, the shear force is reduced by more than 9%, and the non-flowing water content is increased by more than 5%.

3. Use of the method of any one of claims 1-2 in the field of food processing.

4. Red-braised pork prepared by the method of any one of claims 1-2.

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