Potato sirloin prefabricated dish processing method based on composite tenderization, vacuum stewing and low-temperature plasma flexible sterilization

Abstract

The invention discloses a potato sirloin prefabricated dish processing method based on composite tenderization, vacuum stewing and low-temperature plasma flexible sterilization. Comprising the following steps: constructing a composite tenderization solution by adopting compound enzyme, ginger juice and calcium chloride, tenderizing the sirloin under the condition of vacuum rolling, analyzing the tenderization degree of the sirloin by using index systems such as shear force and water-holding capacity, and constructing an efficient composite tenderization process of the sirloin. A multifunctional integrated processing pot is used for stewing, the influence of stewing pressure, stewing temperature, stewing time and the like under a certain vacuum degree on the quality of the sirloin is studied, and standardized parameters of a vacuum stewing process are established; a low-temperature plasma flexible sterilization technology is adopted to carry out low-temperature sterilization on the potato sirloin prefabricated dish, and suitable technological parameters for industrial packaging and sterilization are established. The potato sirloin premade dish is excellent in flavor, stable in quality, convenient and safe to eat, accurate and controllable in technological parameters, long in shelf life of cold chain products and suitable for large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and relates to a method for processing a beef pre-cooked dish, and specifically to a method for processing a potato and sirloin pre-cooked dish based on composite tenderization, vacuum stewing and low-temperature plasma flexible sterilization. Background Art

[0002] As people's pace of life accelerates, highly standardized pre-prepared meals are becoming more and more popular due to their convenience, hygiene, safety, time saving and other advantages. Pre-prepared meals generally refer to semi-finished or finished products made from various agricultural, livestock, poultry and aquatic products as raw materials, seasonings and other auxiliary materials, and processed through pre-selection, modulation and other processes. Usually, pre-prepared meals need to be stored or transported under cold chain conditions for consumers or catering processors to simply heat or cook before eating.

[0003] With the rise of pre-prepared meals, my country has also formulated relevant standards and policy support. For example, in April 2020, the Ministry of Industry and Information Technology issued the "QB / T 5471-2020 Convenient Dishes", which gave an accurate definition of pre-prepared meals; in June 2023, the China Quality Certification Center formulated the "CQC / GF PDP 2001-2023 Pre-prepared Meal Product Certification Technical Specifications", which formulated relevant requirements for the nutritional content, microbial risks and cold chain links in pre-prepared meals from an industrial perspective.

[0004] Although the market and policies for pre-prepared dishes have matured, people generally lack confidence in pre-prepared dishes, mainly due to the safety, flavor and nutrition of pre-prepared dishes. Safety is the most important issue in pre-prepared dishes, especially for pre-prepared dishes made of livestock meat. From slaughtering to production process, and then to storage and transportation, the fat content is high and it is very easy to be contaminated by microorganisms and spoil. At the same time, in the traditional production process of pre-prepared dishes, in order to ensure the long storage period of pre-prepared dishes, high-temperature steam sterilization (121℃, 15min-20min) is usually used. However, while high-temperature steam sterilization kills microorganisms, the color, texture, and flavor of the meat are affected by it; more importantly, whether it is heat sterilization or long-term storage, it will cause the decomposition of proteins and small molecules, resulting in the loss of nutrients. Secondly, the taste and flavor of beef brisket caused by high-intensity sterilization are not ideal, which is quite different from freshly prepared dishes. Summary of the invention

[0005] In view of the deficiencies in the above-mentioned prior art, the present invention targets the large amount of beef brisket raw materials produced as a byproduct during the beef processing process in Xilin Gol League, combined with potatoes, the main specialty agricultural products in Inner Mongolia, and the traditional dishes of potato stewed with beef brisket, which have a large market demand, starting from the construction of a standardized processing technology system suitable for the central kitchen production model, through raw material pretreatment, vacuum low-temperature stewing process development, and product microbial index control method optimization, it will provide technical support for the introduction of potato and beef brisket pre-prepared dishes to the market, promote enterprises to improve quality and efficiency, and play a demonstration and leading role in promoting the development of Xilin Gol League beef pre-prepared dish industry. Specifically, the present invention has developed a potato and beef brisket pre-prepared dish that meets the taste of the public and tastes close to that of freshly prepared dishes, and adopts a new process combining composite tenderization, vacuum stewing and low-temperature plasma flexible sterilization, while eliminating microbial contamination, retaining the taste and nutritional components of the beef brisket in the pre-prepared dish as much as possible.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] The present invention relates to a method for processing a potato and beef brisket pre-cooked dish, the method comprising the following steps:

[0008] S1. Composite tenderization: using exogenous composite enzyme, ginger juice and calcium chloride to construct composite tenderization solution, and tenderizing beef brisket under vacuum tumbling;

[0009] S2, vacuum stewing;

[0010] S3, low-temperature plasma flexible sterilization.

[0011] As an embodiment, the exogenous complex enzyme is a complex enzyme composed of papain and bromelain in a mass ratio of 3:1-1:3.

[0012] As an embodiment, the composite tenderizing solution contains 0.04-0.1% composite enzyme, 2%-5% ginger juice, and 10-20% calcium chloride.

[0013] As an embodiment, the enzymatic hydrolysis temperature of the tenderizing treatment is 40-55°C, and the enzymatic hydrolysis time is 60-75 minutes.

[0014] As an embodiment, the vacuum stewing is stewing for 120 to 300 minutes at a vacuum degree of 0.7 to 0.9 bar and a stewing temperature of 50 to 70°C.

[0015] As an embodiment, the low-temperature plasma flexible sterilization selects nitrogen or air as the carrier gas, the voltage is 120 to 160 kV, and the sterilization time is 150 to 450 s.

[0016] As an embodiment, the sirloin is pre-treated before tenderizing; the pre-treatment includes thawing the frozen sirloin, removing excess fat and fascia tissue on the surface, and then cutting the sirloin into pieces according to the direction of muscle fibers.

[0017] As an embodiment, in step S1, the composite tenderizing solution is placed in a vacuum cooking bag, and the pre-treated beef chunks are placed therein to tenderize the beef uniformly for 0.5-1.5 hours; and then the beef is placed in a vacuum tumbling machine for further tenderization.

[0018] As an implementation scheme, step S2 specifically includes: blanching potatoes to remove starch; putting the blanched beef brisket, the original soup used during blanching (the amount of original soup covering the beef brisket), and spices into a vacuum stew pot, adding tomato paste, curry and seasonings and stewing; after vacuum stewing at -0.8±0.1 bar for 60 to 180 minutes, adding potatoes, and stewing for another 10 to 20 minutes.

[0019] As an implementation scheme, the mass ratio of papain to bromelain in the composite tenderizing solution is 2:2, the amount of protease added is 0.08%, the CaCl2 content is 15%, and the amount of ginger juice added is 5%; the enzymatic hydrolysis temperature is 40°C, and the enzymatic hydrolysis time is 60min; vacuum stewing is carried out for 3h at -0.8bar, and the stewing temperature is 70°C; low-temperature plasma sterilization treatment selects air as the carrier gas, the voltage is 160KV, and the sterilization time is 450S.

[0020] As an implementation scheme, step S3 specifically includes: putting the potato and sirloin pre-prepared dish into a plastic box and sealing it, placing it in a metal conveyor belt between two electrodes, adding a carrier gas for low-temperature plasma sterilization, and storing the processed potato and sirloin pre-prepared dish in a low-temperature cold chain. The low temperature is 4 to -18°C. The potato and sirloin pre-prepared dish has a good flavor, stable quality, is convenient and safe to eat, and the process parameters are precisely controllable. The product can have a shelf life of 7 to 10 days at 4°C in the cold chain.

[0021] In some specific embodiments, the potato and sirloin pre-cooked dish processing based on composite tenderization and vacuum stewing and the low-temperature plasma flexible sterilization process thereof provided by the present invention include the following steps:

[0022] S1. Take the frozen beef brisket out of the refrigerator and thaw it in a sink with tap water. Take out the thawed beef brisket, remove the excess fat and fascia tissue on the surface, and then cut the beef brisket into pieces in the direction of the muscle fibers, so that each piece is about 30g in size and the size and shape are consistent. Use tap water to rinse off the internal congestion. Drain the excess water on the surface of the beef brisket and let it stand for later use.

[0023] S2. Composite tenderization of beef: Select fresh and clean ginger, peel and wash it, then cut it into small pieces, use a pulper to squeeze the juice, first use four layers of gauze for coarse filtration, then use a centrifuge for centrifugal separation (4000r / min, 15min), take the supernatant and put it in the refrigerator for later use. Use papain, bromelain, ginger juice and calcium chloride to prepare 20mL of composite tenderizing enzyme liquid, put it in a vacuum cooking bag, put the processed beef cubes in it, and tenderize the beef evenly in the tenderizing liquid for one hour. Then put it in a vacuum tumbling machine for tenderization again.

[0024] S3. Vacuum stewing process: Cut the beef brisket into pieces and blanch it (add cooking wine, 10g), skim off the foam during the blanching process, remove the beef brisket after 10 minutes, rinse with cold water, and drain the water for later use. Blanch the potatoes for 5-10 minutes, wash off the starch, put the beef brisket, the original soup (about 350mL, covering the beef brisket) and spices (10g cooking wine, a small amount of star anise, cinnamon, and bay leaves) into the vacuum stew pot, set the parameters (stewing time 60-180min, stewing temperature 50-100℃), put the beef brisket, tomato paste, curry and seasoning (5g salt, 30g sugar, 5g MSG) into the pot and stew, add the potatoes after vacuum stewing at about -0.8bar for 60-180min, and stew for another 10-20min before serving.

[0025] S4. Take 350 grams of the potato and beef brisket pre-prepared dish prepared by tenderization and vacuum stewing process, put it into a square plastic box and seal it, then place it on a metal conveyor belt between two electrodes, add different carrier gases (100% N2, 100% air), and perform low-temperature plasma sterilization on the pre-prepared dish samples at different power supply voltages (120-160 kV) and sterilization times (150-450 s). The treated potato and beef brisket pre-prepared dish is stored in a low-temperature (4--18°C) cold chain.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention develops a new process for preparing potato and sirloin dishes that combines composite tenderization, vacuum stewing, and low-temperature plasma flexible sterilization. While eliminating microbial contamination, the process preserves the taste and nutritional components of the sirloin in the prepared dish as much as possible, provides standardized process parameters, and provides a scientific process method for large-scale production.

[0028] (2) The low-temperature plasma flexible sterilization process established by the present invention can extend the shelf life of pre-prepared dishes at 4°C cold chain to 7 to 10 days. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0030] Figure 1 This is the beef tenderizing process of potato sirloin pre-prepared vegetable in Example 1, wherein (A) is the effect of the ratio of compound protease on the tenderizing effect; (B) is the effect of the amount of compound protease added on the tenderizing effect; (C) is the effect of the enzymatic hydrolysis time of the compound protease on the tenderizing effect; (D) is the effect of the enzymatic hydrolysis temperature of the compound protease on the tenderizing effect; (E) is the effect of CaCl2 concentration on the tenderizing effect; and (F) is the effect of ginger juice on the tenderizing effect.

[0031] Figure 2 The change of shear force of beef brisket at different stewing time and temperature.

[0032] Figure 3 The changes in sensory evaluation of beef brisket at different stewing times and temperatures.

[0033] Figure 4 This is the change in crude protein content after low-temperature plasma sterilization.

[0034] Figure 5 The total number of colonies changes during the storage period after low-temperature plasma sterilization treatment.

[0035] Figure 6 The changes of volatile compounds before and after low-temperature plasma sterilization; among them, US1, US2, US3 refer to three parallel samples without sterilization; LTPS1, LTPS2, LTPS3 refer to three parallel samples sterilized by low-temperature plasma; HSS1, HSS2, HSS3 refer to three parallel samples sterilized by high temperature and short time (121℃, 20min). DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, some adjustments and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0037] In the following embodiments, the beef brisket is first subjected to conventional pretreatment; in the present invention, the frozen beef brisket is taken out of the refrigerator and put into a sink to thaw with tap water. The thawed beef brisket is taken out, and the excess fat and fascia tissue on the surface are removed. The beef brisket is then cut into pieces in the direction of the muscle fibers so that each piece of beef brisket is about 30 g in size and has the same size and shape. The internal blood congestion is washed off with tap water. Finally, the excess water on the surface of the beef brisket is absorbed with a paper towel and then left to stand for use.

[0038] The ginger juice to be used can be fresh and clean ginger, which can be peeled and washed, then cut into small pieces, squeezed with a blender, coarsely filtered with four layers of gauze, and then centrifuged with a centrifuge (4,000 r / min, 15 min), and the supernatant can be put in the refrigerator for later use.

[0039] The shear force determination was based on the method of Gao Xueqin et al. (Effects of three protease complexes on beef tenderization [J]. Modern Animal Husbandry, 2022, 6(01): 19-24+29.). The tenderized beef brisket was placed in a steaming bag, and the air in the bag was exhausted as much as possible. The bag was placed in an 80°C constant temperature water bath and heated until the center temperature of the beef reached 70°C. The temperature was maintained for 10 minutes. The beef was taken out and cooled to room temperature. The samples were cut into 1.5 cm × 1.5 cm × 2 cm samples according to the muscle fiber direction. The TAP texture analysis was determined by the texture analyzer. Each sample was measured 3 times, and the average shear force was calculated. The untenderized beef tenderloin was used as a control. Parameters: The pre-test and test rates were both 1 mm / s, the post-test rate was 1.5 mm / s, the trigger force was 5 g, and the downward distance was 12 mm.

[0040] The color difference of beef samples was measured using a portable colorimeter. Before measurement, a matching white standard plate was used for calibration and zeroing.

[0041] For microbiological determination, please refer to GB 4789.2-2022 "National Food Safety Standard for Food Microbiological Examination for Total Colony Count". For pathogenic bacteria detection, refer to GB 4789.4-2016 Food Microbiological Examination for Salmonella. For Listeria monocytogenes, refer to GB 4789.30-2016 Food Microbiological Examination for Listeria monocytogenes. For Staphylococcus aureus, refer to GB 4789.10-2016 Food Microbiological Examination for Staphylococcus aureus. For diarrheagenic Escherichia coli, refer to GB 4789.6-2016 Food Microbiological Examination for Diarrheagenic Escherichia coli.

[0042] The protein content test refers to "GB 5009.6-2016 National Food Safety Standard Determination of Protein in Food".

[0043] The detection parameters and quantitative methods of volatile aroma compounds are as follows:

[0044] 1) Parameters: GC conditions: RTX-WAX polyethylene glycol strong polar capillary column (30m×0.25mm, 0.25μm); temperature program: start at 40℃ and hold for 2min, increase to 130℃ at 2℃ / min, increase to 220℃ at 4℃ / min, hold for 4min, increase to 250℃ at 10℃ / min, hold for 5min; carrier gas (He) (purity 99.999%) flow rate 1.6mL / min, pressure 2.4kPa; injection mode: injection port temperature 200℃. MS conditions: electron ionization source; electron energy 70eV; transfer line temperature 275℃; ion source temperature 230℃; parent ion m / z 285; activation voltage 1.5V; mass scanning range m / z 35-350.

[0045] 2) Quantitative method: Use 2-octanol as the internal standard substance. Add 5 μl of 40 μg / mL 2-octanol to 1000 mg of sample.

[0046] In the nutrient component testing, energy and carbohydrates refer to "GB 28050-2011 National Food Safety Standard General Rules for Nutrition Labeling of Prepackaged Foods". Protein and fat refer to "GB 5009.6-2016 National Food Safety Standard Determination of Protein in Foods". Sodium refers to "GB5009.91-2017 National Food Safety Standard Determination of Potassium and Sodium in Foods".

[0047] Example 1

[0048] This embodiment provides a beef tenderization process, comprising the following steps:

[0049] Use papain, bromelain, ginger juice (1 mL) and calcium chloride (5 mL) to prepare 20 mL of composite tenderizing enzyme solution (wherein the amount of composite enzyme added is 0.06%). Prepare the tenderizing enzyme solution according to 10% of the meat mass, based on 10 g of sirloin and 20 mL of composite tenderizing enzyme solution, place the composite tenderizing enzyme solution in a vacuum cooking bag, put the processed sirloin pieces in it, tenderize the sirloin evenly in the tenderizing solution, tenderize for one hour, and then place it in a vacuum tumbling machine for re-tenderization.

[0050] In this example, under the conditions of enzymatic hydrolysis temperature of 40° C. and enzymatic hydrolysis for 60 min, shear force was used as an indicator to investigate the effect of the mass ratio of papain to bromelain (4:0, 3:1, 2:2, 1:3, 0:4) on the tenderness of beef brisket.

[0051] like Figure 1As shown in A, after adding the composite protease, the average shear force of the beef brisket was significantly reduced (P < 0.05), and different protease ratios had different results on the tenderization of beef brisket. When the ratio of papain to bromelain was 2:2, the average shear force was the lowest and the tenderization effect was the best. As the ratio of bromelain gradually increased, the average shear force began to rise. Therefore, papain is more advantageous than bromelain in tenderizing beef brisket. Therefore, the most suitable ratio of protease tenderizing solution is 2:2.

[0052] Further, under the conditions of papain to bromelain mass ratio of 2:2, enzymatic hydrolysis temperature of 40°C, and enzymatic hydrolysis time of 60 min, the effect of the addition amount of composite enzyme (0.02%, 0.04%, 0.06%, 0.08%, 0.10%) on the tenderness of beef brisket was explored.

[0053] like Figure 1 As shown in Figure B, the compound protease has a certain tenderizing effect on beef brisket. As the amount of compound protease added increases, the average shear force becomes smaller and smaller, and the tenderizing effect on beef brisket becomes more and more obvious. The average shear force drops rapidly when the amount of protease added is 0.02%-0.06%, and the downward trend slows down when it is 0.06%-0.1%. When the amount of compound protease added is 0.1%, the tenderizing effect of beef brisket is the best. Therefore, the optimal addition amount of protease tenderizing solution is 0.1%.

[0054] Further, the effect of enzymatic hydrolysis time (30min, 40min, 50min, 60min, 70min, 80min, 90min) on the tenderness of beef brisket was investigated under the conditions of a papain to bromelain mass ratio of 2:2, a composite enzyme addition amount of 0.06%, and an enzymatic hydrolysis temperature of 40°C.

[0055] like Figure 1 As shown in Figure C, the experimental results show that the duration of the composite protease tenderization has a certain effect on the tenderness of the beef brisket. As the temperature rises, the average shear force of the beef brisket gradually decreases. When the enzymatic hydrolysis time is 60°C, the average shear force of the beef brisket is the lowest. Subsequently, possibly affected by the enzyme activity, the average shear force of the beef brisket rebounded. Therefore, the optimal enzymatic hydrolysis time of the protease tenderizing solution is 60 minutes.

[0056] Further, the effect of enzymatic hydrolysis temperature (30℃, 35℃, 40℃, 45℃, 50℃) on the tenderness of beef brisket was investigated under the conditions of a papain to bromelain mass ratio of 2:2, a composite enzyme addition amount of 0.06%, and an enzymatic hydrolysis time of 60 min.

[0057] like Figure 1As shown in Figure D, the temperature during the tenderization of the composite protease has a certain effect on the tenderness of the beef brisket. As the enzymatic hydrolysis temperature increases, the average shear force of the beef brisket gradually decreases. When the temperature is 45°C, the average shear force of the beef brisket is the lowest, and the tenderness is the best at this time. Subsequently, possibly affected by the optimal temperature of the enzyme, the average shear force of the beef brisket gradually recovers. Therefore, the optimal enzymatic hydrolysis temperature of the protease tenderizing solution is 45°C.

[0058] After preparing the composite tenderizing solution with the above-mentioned optimized factors, that is, under the conditions of a papain to bromelain mass ratio of 2:2, a composite enzyme addition amount of 0.06%, an enzymatic hydrolysis temperature of 45°C, and an enzymatic hydrolysis time of 60 min, the shear force / myofibrillar fragmentation index was used as an indicator to study the effects of different concentrations of calcium chloride of 0, 5%, 10%, 15%, and 20% (mass ratio, meat: solution = 1:2) and an immersion time of 3 h on the tenderness of beef brisket.

[0059] like Figure 1 As shown in Figure E, CaCl2 has a significant effect on the tenderness of beef brisket. As the concentration of CaCl2 increases, the average shear force of beef brisket gradually decreases. When the content is 15%, the average shear force value of beef brisket is the lowest, and the tenderness is the best at this time.

[0060] Continue to tenderize the beef with 3%, 4%, 5%, 6% and 7% ginger juice added at a papain to bromelain ratio of 2:2, a composite enzyme addition of 0.06%, a CaCl2 content of 15%, a hydrolysis temperature of 45°C and a hydrolysis time of 60 min. The shear force of the sirloin was used as an indicator to compare the tenderizing effect of ginger juice on beef at different addition amounts.

[0061] like Figure 1 As shown in Figure F, ginger juice has a certain tenderizing effect on beef brisket. As the amount of ginger juice added increases, the average shear force becomes smaller and smaller, and the tenderizing effect on beef brisket becomes more and more obvious. When the amount of ginger juice added is 1%-5%, the average shear force slowly decreases. When the amount of ginger juice added is 5%, the tenderizing effect of beef brisket is the best. Therefore, the optimal amount of ginger juice added is 5%.

[0062] Table 1 Protease composite orthogonal experiment table

[0063]

[0064]

[0065] Further, using shear force as an indicator, a protease composite orthogonal experiment was conducted to study the effects of three different factors (enzyme hydrolysis temperature, enzyme hydrolysis time, and amount of composite protease added) on the tenderness of sirloin. As shown in Table 1, the range is A>C>B, so the strength of the influence on the tenderness of sirloin is: enzyme hydrolysis temperature has the greatest impact on tenderness, followed by enzyme hydrolysis time, and the amount of addition has a relatively small impact on the tenderness of sirloin. Since the smaller the shear force, the better the tenderness of the sirloin, according to the size of the k value, it can be seen that the optimal ratio of composite protease tenderizing sirloin is: A1B2C2, that is, the formula of the composite protease tenderizing solution is: protease addition is 0.08%, enzyme hydrolysis temperature is 40℃, and enzyme hydrolysis time is 60min.

[0066] In summary, the optimal tenderizing process is: the mass ratio of papain to bromelain is 2:2, the amount of protease added is 0.08% (w / w), the hydrolysis temperature is 40℃, and the hydrolysis time is 60min; when the CaCl2 content is 15% and the amount of ginger juice added is 5% (w / w), the tenderness of the beef brisket is the best.

[0067] Example 2

[0068] This embodiment provides an optimization of a vacuum stewing process for beef, comprising the following steps:

[0069] Cut the tenderized beef brisket into pieces and blanch them in water (add 10g cooking wine). Skim off the foam during the blanching process. After 10 minutes, remove the beef brisket and rinse it in cold water, then drain the water and set aside. Blanch the potatoes for 5-10 minutes, wash off the starch, put the beef brisket, the original soup (about 350mL, covering the beef brisket) and spices (10g cooking wine, a small amount of star anise, cinnamon and bay leaves) into a vacuum stew pot, put the beef brisket, tomato paste, curry and seasoning (5g salt, 30g sugar, 5g MSG) into the pot and stew, vacuum stew at -0.8bar, 70℃ for 180min, and serve.

[0070] In this example, 0.5 kg of beef brisket tenderized by the optimal tenderizing process of Example 1 was taken. The beef brisket, seasonings and the original soup from blanching were placed in a multifunctional processing pot. The stewing temperature was set to 50°C, 60°C, 70°C and 80°C, and each temperature was stewed for five hours. 3-4 pieces of beef brisket were taken every hour, and the effect of stewing temperature on the quality of beef brisket was explored using shear force as an indicator. The four best parameters were selected, and the overall texture and color value were tested to select the best process parameters. Among them, the beef brisket that had not been cooked after tenderization was used as a blank control.

[0071] Using different stewing temperatures and stewing times, the average shear force of the beef brisket will decrease, and the tenderness will also decrease. Figure 2As shown in the figure, the shear force of raw beef brisket decreases rapidly after blanching, and the average shear force is about 3000gf. With the increase of stewing time, the average shear force shows a trend of first decreasing and then increasing. Under different stewing temperatures, the time point when the minimum average shear force of beef brisket appears will be delayed accordingly. For example, at 50℃, when the beef brisket is stewed at negative pressure for 5h, its average shear force is the smallest and the tenderness is the best; while at 60℃, when it is stewed at negative pressure for 4h, the average shear force is the smallest and the tenderness is the best. Therefore, four different process parameters of 50℃, 5h, 60℃, 4h, 70℃, 3h, and 80℃, 2h were selected, and the process was optimized through full texture, color value, water holding capacity detection and sensory evaluation. According to the shear force of beef brisket ( Figure 2 ), texture change (Table 2), water holding capacity (Table 2), color value (Table 3) and sensory evaluation ( Figure 3 ) concluded that the best vacuum stewing process is when the stewing temperature is 70℃ and the stewing time is 3h. Under this process condition, the beef product has the best tenderness and chewiness, higher elasticity and better beef aroma.

[0072] Table 2 Texture changes of beef brisket after stewing

[0073]

[0074] Table 3 Color value changes of stewing

[0075]

[0076] Example 3

[0077] The present embodiment provides an optimization of the low-temperature plasma sterilization process for potato and sirloin pre-prepared dishes, comprising the following steps: taking 350 grams of potato and sirloin pre-prepared dishes prepared by the optimal tenderizing process in Example 1 and the optimal stewing process in Example 2, placing them in a reactor between two electrodes, adding different carrier gases (100% N2, 100% air), sterilizing the pre-prepared dish samples at different power supply voltages (120-160 kV) and sterilization times (150-450 s), and immediately performing microbial detection on the treated potato and sirloin pre-prepared dishes.

[0078] Considering the shear force before and after sterilization (Table 4), microorganisms (Table 5, Table 6) and protein content ( Figure 4 ) changes, as well as sterilization costs, air was selected as the carrier gas, voltage was 160KV, and sterilization time was 450S as the optimal sterilization process parameters. Under this flexible sterilization condition, the tenderness of beef products was higher (Table 4), and the protein content of the products was higher ( Figure 4 ), and at the same time, the microbial growth of pre-prepared food products was well inhibited (Table 6). Figure 5It can be seen that the total colony count of the potato and beef brisket pre-prepared dishes during the 10-day storage period after low-temperature plasma sterilization and high-temperature short-time sterilization increases with the extension of storage time. Microbial activity was detected in the samples after low-temperature plasma sterilization on the third day after sterilization, but on the 10th day, the total colony count was less than 10lg (CFU / g), which meets the national standard of <10000CFU. The sterilization effect is close to that of high-temperature short-time (121℃, 30min), and the safe shelf life of the product reaches 10 days during the 4℃ cold chain storage process.

[0079] Table 4 Effect of different low-temperature plasma sterilization processes on the shear force of potato and sirloin pre-prepared dishes

[0080] Sterilization process parameters Shear force Sterilization process parameters Shear force Control 1 (unsterilized) 2594.325±486.317a Control 2 (high temperature short time sterilization) 1664.9698±219.220c N2 120KV 150S 2100.5282±347.996ab Air 120KV 150S 2235.7744±403.876b N2 120KV 300S 2215.8756±262.637ab Air 120KV 300S 2267.9164±260.689ab N2 120KV 450S 2220.4216±422.630ab Air 120KV 450S 2191.2994±352.042ab N2 140KV 150S 2262.8008±325.548ab Air 140KV 150S 2028.7314±217.856b N2 140KV 300S 2093.322±203.655ab Air 140KV 300S 2139.8526±316.531ab N2 140KV 450S 2124.9094±325.234ab Air 140KV 450S 2035.4436±283.301b N2 160KV 150S 2381.8436±354.900ab Air 160KV 150S 2083.3482±325.415b N2 160KV 300S 2396.6728±312.914ab Air 160KV 300S 2270.7982±139.248ab N2 160KV 450S 2294.1552±287.102ab Air 160KV 450S 2049.2166±430.939b

[0081] Table 5 Effects of different low-temperature plasma sterilization processes on the microorganisms of potato and sirloin pre-prepared dishes

[0082]

[0083]

[0084] Table 6. Effects of different low-temperature plasma sterilization processes on the microorganisms of potato and sirloin pre-prepared dishes

[0085]

[0086] Example 4

[0087] Considering the changes in microorganisms and shear force before and after sterilization, as well as the sterilization cost, in this embodiment, air is selected as the carrier gas, the voltage is 160KV, and the sterilization time is 450S as the sterilization process parameters; the pre-prepared food samples prepared by the optimal tenderization process in Example 1 and the optimal stewing process in Example 2 are sterilized by low-temperature plasma. The specific steps are as follows:

[0088] S1. Take the frozen beef brisket out of the refrigerator and thaw it in a sink with tap water. Take out the thawed beef brisket, remove the excess fat and fascia tissue on the surface, and then cut the beef brisket into pieces in the direction of the muscle fibers, so that each piece is about 30g in size and the size and shape are consistent. Use tap water to rinse off the internal congestion. Drain the excess water on the surface of the beef brisket and let it stand for later use.

[0089] S2. Composite tenderization of beef: Select fresh and clean ginger, peel and wash it, then cut it into small pieces, use a pulper to squeeze the juice, first use four layers of gauze for coarse filtration, then use a centrifuge for centrifugal separation (4000r / min, 15min), take the supernatant and put it in the refrigerator for use. Use papain, bromelain, ginger juice and calcium chloride to prepare 20mL of composite tenderization liquid, put it in a vacuum cooking bag, put the processed beef cubes in it, and tenderize the beef evenly in the tenderization liquid for one hour. Then put it in a vacuum tumbling machine for tenderization again. The mass ratio of papain to bromelain is 2:2, and the amount of protease added is 0.08% (w / w). The tenderization temperature is 40℃, the tenderization time is 60min; the CaCl2 content is 15%, and the amount of ginger juice added is 5%.

[0090] S3. Vacuum stewing process: Cut the beef brisket into pieces and blanch it (add cooking wine, 10g), skim off the foam during the blanching process, remove the beef brisket after 10 minutes, rinse with cold water, drain the water and set aside. Blanch the potatoes for 5-10 minutes, wash off the starch, put the beef brisket, the original soup (about 350mL, covering the beef brisket) and spices (10g cooking wine, a small amount of star anise, cinnamon, and bay leaves) into the vacuum stew pot, put the beef brisket, tomato paste, curry and seasoning (5g salt, 30g sugar, 5g MSG) into the pot and stew, vacuum stew at -0.8bar, 70℃ for 180min, and serve.

[0091] S4. 350 grams of the potato and beef brisket pre-prepared dish prepared by tenderization and vacuum stewing process were put into a square plastic box and sealed, and then placed in a metal conveyor belt between two electrodes, and air was selected as the carrier gas, the voltage was 16KV, and the sterilization time was 450S as the sterilization process parameters to perform low-temperature plasma sterilization on the pre-prepared dish sample. The process had a good sterilization effect (Table 7) and retained the taste and nutritional components of the beef brisket in the pre-prepared dish as much as possible (Table 8).

[0092] Table 7 Pathogenic bacteria detection of finished potato and beef brisket pre-prepared dishes

[0093]

[0094] Table 8 Nutritional composition of finished potato and sirloin pre-prepared dishes

[0095]

[0096] Further investigation of the changes in volatile compounds before and after sterilization, such as Figure 6As shown in Table 9, a total of 199 volatile compounds were detected by HS-SPME-GC / MS. Including 35 aldehydes, 17 esters, 21 ketones, 11 furans, 7 acids, 15 alkenes, 24 alkanes, 7 phenols, 8 ethers, 5 sulfides, 5 aromatics, 2 pyrroles, 3 pyrazines, 2 pyridines, and 2 other compounds. Cluster analysis shows that the flavor of US samples (unsterilized) is closer to that of LP samples (low-temperature sterilized). At the same time, the abundance of volatile compounds increased after thermal sterilization. Among them, β-ionone, acetaldehyde, anisaldehyde, anethole and 3-methylthiopropionaldehyde have the highest OAV values. The HS (high-temperature sterilization) sample is quite different from the other two sterilization treatments, which is consistent with the cluster analysis.

[0097] Table 9 Main differences in volatile compounds after sterilization (OAV>1, VIP>1)

[0098]

[0099]

[0100] In summary, the present invention provides a potato sirloin pre-cooked dish processing based on composite tenderization and vacuum stewing and a low-temperature plasma flexible sterilization process thereof; the process comprises the following steps: (1) thawing the frozen sirloin, removing excess fat and fascia tissue on the surface, and then cutting the sirloin into pieces in the direction of muscle fibers; (2) using a composite enzyme (papain, bromelain, etc.), ginger juice, and calcium chloride to construct a composite tenderizing solution, performing a sirloin tenderizing treatment under vacuum tumbling, and evaluating the sirloin tenderization using an index system such as shear force, water holding capacity, and myofibril fragmentation index. (3) Use a multifunctional integrated processing pot for stewing to explore the effects of stewing pressure, stewing temperature, stewing time, material-water ratio, and the addition of auxiliary materials such as seasonings on the quality of beef brisket under a certain vacuum degree, and establish standardized parameters for vacuum stewing process; (4) Use low-temperature plasma flexible sterilization technology to sterilize potato and beef brisket pre-prepared dishes at low temperature, and establish process parameters suitable for industrial packaging and sterilization of flavored potato and beef brisket. The potato and beef brisket pre-prepared dish has excellent flavor, stable quality, convenient and safe to eat, precise and controllable process parameters, and extended shelf life of cold chain products, which is suitable for large-scale production.

[0101] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for processing a potato and beef brisket pre-cooked dish, characterized in that: The method comprises the following steps: S1. Composite tenderization: using exogenous composite enzyme, ginger juice and calcium chloride to construct composite tenderization solution, and tenderizing beef brisket under vacuum tumbling; S2, vacuum stewing; S3, low-temperature plasma flexible sterilization.

2. The method for processing potato and sirloin prepared dishes according to claim 1, characterized in that: The exogenous complex enzyme is a complex enzyme composed of papain and bromelain in a mass ratio of 3:1-1:

3.

3. The method for processing potato and sirloin prepared dishes according to claim 1, characterized in that: The composite tenderizing solution contains 0.04-0.1% of composite enzyme, 2%-5% of ginger juice and 10-20% of calcium chloride.

4. The method for processing potato and sirloin prepared dishes according to claim 1, characterized in that: The enzymatic hydrolysis temperature of the tenderizing treatment is 40-55° C., and the enzymatic hydrolysis time is 60-75 min.

5. The method for processing potato and sirloin prepared dishes according to claim 1, characterized in that: The vacuum stewing is stewing for 120 to 300 minutes at a vacuum degree of 0.7 to 0.9 bar and a stewing temperature of 50 to 70°C.

6. The method for processing potato and sirloin prepared dishes according to claim 1, characterized in that: The low-temperature plasma flexible sterilization selects nitrogen or air as carrier gas, the voltage is 120-160 kV, and the sterilization time is 150-450 s.

7. The method for processing potato and sirloin prepared dishes according to claim 1, characterized in that: The sirloin is pre-processed before tenderization; the pre-processing includes thawing the frozen sirloin, removing excess fat and fascia tissue on the surface, and then cutting the sirloin into pieces according to the direction of muscle fibers.

8. The method for processing potato and sirloin prepared dishes according to claim 1, characterized in that: In step S1, the composite tenderizing solution is placed in a vacuum cooking bag, and the pre-treated beef chunks are placed therein to tenderize the beef uniformly for 0.5-1.5 hours; and then the beef chunks are placed in a vacuum tumbling machine for further tenderization.

9. The method for processing potato and sirloin prepared dish according to claim 1, characterized in that: Step S2 specifically includes: blanching potatoes to remove starch; putting the blanched beef brisket, the original soup used during blanching (the amount of the original soup covering the beef brisket), and spices into a vacuum stew pot, adding tomato paste, curry and seasonings and stewing; after vacuum stewing at -0.8±0.1bar for 60 to 180 minutes, adding potatoes, and stewing for another 10 to 20 minutes.

10. The method for processing potato and sirloin prepared dish according to claim 1, characterized in that: The mass ratio of papain to bromelain in the composite tenderizing solution is 2:2, the amount of protease added is 0.08%, the CaCl2 content is 15%, and the amount of ginger juice added is 5%; the enzymatic hydrolysis temperature is 40°C, and the enzymatic hydrolysis time is 60 minutes; the vacuum stewing is performed for 3 hours at -0.8 bar, and the stewing temperature is 70°C; the low-temperature plasma sterilization treatment selects air as the carrier gas, the voltage is 160KV, and the sterilization time is 450S.

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