Locking juice preservation method of beef pre-prepared dishes

Abstract

The application discloses a lock juice preservation method of beef prepared dishes, and belongs to the technical field of food processing. The method comprises the following steps: placing beef pieces in a vacuum tumbling machine, adding a preservation liquid for tumbling treatment, vacuum packaging, carrying out two-stage low-temperature slow cooking (the first stage is 58-62 DEG C, and the second stage is 70-75 DEG C), and then rapidly cooling. Through the synergistic effect of LEPYI and various preservation components, in combination with the vacuum tumbling and two-stage slow cooking process, the bacteriostatic spectrum is significantly widened, fat oxidation is effectively inhibited, and the shelf life of the beef prepared dishes under the cold storage condition at 4 DEG C is prolonged to more than 30 days, so that the method has important industrial application value.

Description

Technical Field

[0001] This application relates to the technical field of food processing, and in particular to a method for preserving the juices of beef pre-cooked dishes. Background Technology

[0002] In the food processing sector, the development of ready-to-eat meals meets the demand for convenient and delicious food in today's fast-paced lifestyle, especially ready-to-eat beef meals, which are popular among consumers due to their high protein and other nutritional content. As people's living standards improve, the requirements for the quality and freshness of ready-to-eat beef meals are also increasing. How to extend the shelf life of beef while ensuring its taste and nutritional value has become a key focus for the industry. This not only relates to the consumer's eating experience but also has a significant impact on the production and sales of food processing companies.

[0003] Various methods are employed in the industry for the preservation and cooking of prepared beef dishes. Slow cooking is a common method that achieves uniform cooking of the beef and maintains a high water retention rate. Additionally, to extend shelf life, conventional practices include adding synthetic materials. Furthermore, some biological preservatives, such as nisin or ε-polylysine, are also used. Tea polyphenols are also frequently used for their antioxidant and antibacterial properties.

[0004] However, these existing technologies have significant drawbacks. While sous-vide cooking has certain advantages, the low processing temperature makes it difficult to fully inactivate spoilage spores, resulting in a shorter shelf life of the product under refrigeration. Regarding biological preservatives, nisin effectively inhibits Gram-positive bacteria and some spore germination, but it has almost no inhibitory effect on Gram-negative bacteria (such as Pseudomonas and Enterobacteriaceae, which are the dominant spoilage bacteria in refrigerated beef), exhibiting a very narrow antibacterial spectrum. While ε-polylysine has relatively broad-spectrum antibacterial activity, its inhibitory effect on specific bacterial groups such as lactic acid bacteria is weak, and its high concentration required when used alone can lead to increased costs and flavor alterations. Although a simple combination of these two can complement each other's antibacterial spectrum to some extent, in the complex matrix of prepared beef, the dense structure of muscle tissue and the barrier effect of the protein network make it difficult for the preservative to penetrate evenly into the deep layers of the meat, resulting in a lack of effective protection in the internal areas. In addition, the antioxidant and antibacterial activities of tea polyphenols are significantly affected by temperature and contact method. Directly mixing them into the broth cannot fully act on the inside of the meat, and they are easily oxidized and consumed during storage, making it difficult to maintain a long-term protective effect.

[0005] Limited by the insufficient antibacterial spectrum, poor permeability, poor thermal stability, and lack of long-lasting sustained-release ability of the aforementioned preservatives, the shelf life of beef pre-prepared dishes prepared by existing technologies is usually no more than 14 days under refrigeration at 4°C, and obvious flavor deterioration, juice loss, and dark color appear around the 10th day, making it difficult to meet the market demand for high-quality, long-shelf-life beef pre-prepared dishes.

[0006] Therefore, developing a juice-locking preservation process for pre-cooked beef that can effectively broaden the antibacterial spectrum, enhance the penetration and distribution of preservatives in meat tissue, and continuously exert antioxidant and antibacterial effects during storage is of great practical significance. Summary of the Invention

[0007] In a first aspect, this application provides a preservative solution, which, by mass-volume percentage, contains 0.1% to 0.3% tea polyphenols, 0.01% to 0.05% ε-polylysine, 0.005% to 0.02% nisin, 0.03% to 0.1% vitamin C, and 0.05% to 0.2% active polypeptides; wherein the amino acid sequence of the active polypeptides is LEPYI.

[0008] Optionally, the preservative solution, by weight and volume percentage, consists of 0.2% tea polyphenols, 0.025% ε-polylysine, 0.01% nisin, 0.07% vitamin C, and 0.1% active polypeptide LEPYI.

[0009] Secondly, this application provides a method for preserving the juices of prepared beef dishes, comprising the following steps: S1: Place the cut beef chunks in a vacuum tumbler, add the preservative liquid, control the vacuum degree to -0.08~-0.06 MPa, and tumble at 0~4℃ for 10~20 minutes to allow the preservative liquid to penetrate the beef tissue evenly. S2: Remove the beef, drain off excess liquid, put it into a cooking bag, vacuum the bag until the vacuum level inside the bag is below -0.095MPa, and heat seal it. S3: In the first stage, the vacuum-packed beef is heated at 58~62℃ for 25~35 minutes; in the second stage, the temperature is increased to 70~75℃ and heated for another 35~45 minutes. S4: After slow cooking, quickly immerse the bag of beef in an ice-water mixture to cool it until the core temperature is below 4°C, and then transfer it to a cold storage at 0~4°C.

[0010] Optionally, the ratio of the preservative liquid to the beef chunks is 1:0.3 to 1:0.8.

[0011] Optionally, the preservative solution is introduced into the beef tissue by vacuum tumbling or multi-needle vacuum injection.

[0012] Thirdly, this application provides a pre-cooked beef dish prepared using the juice-locking and preservation method described in the second aspect.

[0013] In summary, this application provides a preservative solution and a method for preserving and locking in the juices of prepared beef dishes based on the preservative solution, which has the following advantages compared with the prior art: 1. Significantly broadened antibacterial spectrum: The active polypeptide LEPYI in the preservation solution works synergistically with ε-polylysine and nisin to effectively compensate for the deficiency of nisin in inhibiting Gram-negative bacteria, and achieves broad-spectrum and highly efficient inhibition of a variety of putrefactive bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. 2. Significantly extended shelf life: The preservative liquid is evenly penetrated into the beef tissue through vacuum tumbling, combined with a two-stage low-temperature slow cooking and rapid cooling process, so that the preservative ingredients continue to play a role during the storage period. 3. Clean label and high safety: All preservative ingredients are of natural origin or bio-fermentation products, with no chemically synthesized preservatives, meeting consumers' demand for healthy food. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. Experimental methods not specified in these embodiments can be performed with reference to conventional production processes; unless otherwise specified, the reagents used are commercially available or obtainable through public channels.

[0015] Preparation Example 1: Hericium erinaceus protein hydrolysate The preparation steps of Hericium erinaceus protease hydrolysate are as follows: (1) Take 150g of dried Hericium erinaceus powder and prepare 1000mL of solution with deionized water. Adjust the pH to 9.0 with sodium hydroxide solution (0.1 M). Stir and extract in a 55℃ water bath for 3 hours. Centrifuge the obtained extract at 10,000×g for 20 minutes and collect the supernatant to obtain Hericium erinaceus crude protein extract. (2) Transfer the crude protein extract obtained in step (1) to an enzymatic hydrolysis tank, adjust the pH to 7.0, control the temperature at 37℃, add 0.2kg cellulase, 0.2kg papain and 0.1kg pectinase in sequence, and heat to 50℃ for 2h for enzymatic hydrolysis. (3) Enzyme inactivation process: Heat the product from step (2) to 90°C and inactivate the enzyme for 1 hour; (4) Centrifuge the enzyme hydrolysate at 4℃ and 10000 r / min for 30 minutes and collect the supernatant; (5) The supernatant was filtered through 0.45 μm and 0.22 μm microfiltration membranes for sterilization and impurity removal. Then, the filtrate was separated using an ultrafiltration membrane module with a molecular weight cutoff of 3 kDa, and the permeate with a molecular weight <3 kDa was collected to obtain Hericium erinaceus proteolytic solution.

[0016] Preparation Example 2: Active Polypeptide Peptide identification and screening: The permeate of <3 kDa from Preparation Example 1 was analyzed by LC-MS / MS. The obtained mass spectrometry data were analyzed using the built-in analysis functions of BioChemia (https: / / biochemia.uwm.edu.pl / biopep / peptide_data.php) and InterPro (https: / / www.ebi.ac.uk / interpro / ) databases to confirm the potential biological activity of candidate sequences, and to fully annotate their potential biological activities. Finally, the active peptide was identified and screened from the enzymatic digestion products, with the amino acid sequence LEPYI.

[0017] Synthesis of target peptide: Based on the identification and screening results, the above-mentioned active peptide LEPYI was synthesized in solid phase and purified by preparative high performance liquid chromatography to obtain a high-purity (>95%) peptide standard.

[0018] Example 1

[0019] Preparation of preservation solution: Dissolve 0.2% tea polyphenols, 0.025% ε-polylysine, 0.01% nisin, 0.07% vitamin C and 0.1% active polypeptide LEPYI in deionized water by weight and volume percentage, and stir evenly to obtain the preservation solution.

[0020] A pre-cooked beef dish juice-locking process includes the following steps: S1 Preservative Liquid Introduced into Beef Tissue: Place the cut beef chunks (approximately 200g / piece) into a vacuum tumbler, add the above preservative liquid (material-liquid ratio of 1:0.5), control the vacuum degree to -0.07MPa, and tumble at 4℃ for 15 minutes to allow the preservative liquid to penetrate evenly into the beef tissue. S2 Vacuum Packaging: Remove the beef, drain excess liquid, and immediately pack it into a food-grade nylon / polyethylene composite retort bag. Use a vacuum packaging machine to vacuum the bag until the vacuum level inside the bag is below -0.095MPa, and then heat-seal it. S3 Two-Stage Low-Temperature Cooking: Stage 1: Place the vacuum-packed beef in a constant temperature water bath and heat at 60℃ for 30 minutes; Stage 2: Increase the temperature to 72℃ and continue heating for 40 minutes. S4 Rapid Cooling: After slow cooking, the beef bag is quickly immersed in an ice-water mixture to cool it until the core temperature is below 4°C, and then it is transferred to a 4°C cold storage.

[0021] Example 2 The difference from Example 1 is that the content of active polypeptide LEPYI in the preservation solution is 0.2%, while the other components and process conditions are the same.

[0022] Example 3 The difference from Example 1 is that the content of active polypeptide LEPYI in the preservation solution is 0.05%, while the other components and process conditions are the same.

[0023] Comparative Example 1 The difference from Example 1 is that the active polypeptide LEPYI is not added to the preservation solution, while the other components and process conditions are the same.

[0024] Comparative Example 2 The difference from Example 1 is that only 0.1% of the active polypeptide LEPYI is added to the preservation solution, and no tea polyphenols, ε-polylysine, nisin and vitamin C are added, while the other process conditions are the same.

[0025] Comparative Example 3 The difference from Example 1 is that an equal amount (0.1%) of active polypeptide LLPH was added to the preservation solution to replace the active polypeptide LEPYI, while the other process conditions were the same.

[0026] Performance testing Detection method: 1. Determination of the antibacterial effect of different spoilage bacteria: Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, which are common representative spoilage bacteria in beef pre-cooked dishes, were selected respectively. The inhibition ability of the preservation liquid of the evaluation example and the comparative example on each strain was determined by the double-layer Oxford cup inhibition zone method. 2. Total bacterial count determination: The total bacterial count of the beef obtained in the examples and comparative examples during storage was determined in accordance with GB 4789.2-2022 "National Food Safety Standard - Microbiological Examination of Food - Determination of Total Bacterial Count"; 3. Determination of Thiobarbituric Acid Reactive Material Value (TBARS value): The degree of fat oxidation during storage of beef obtained in the examples and comparative examples was evaluated in accordance with GB / T 5009.181-2016 "National Food Safety Standard - Determination of Malondialdehyde in Food".

[0027] Test results: Table 1. Antibacterial effects of different putrefactive bacteria (inhibition zone diameter, mm) Group Staphylococcus aureus Pseudomonas aeruginosa E. coli Example 1 19.2 18.6 17.3 Example 2 20.1 19.4 18.2 Example 3 17.8 17.2 16.1 Comparative Example 1 14.8 9.5 11.2 Comparative Example 2 9.2 10.1 9.8 Comparative Example 3 16.5 10.3 10.5 Table 2. Changes in total bacterial count during storage (lg(CFU / g)) Group Storage for 0 days Store for 30 days Example 1 2.3 3.2 Example 2 2.2 2.9 Example 3 2.3 3.8 Comparative Example 1 2.1 6.7 Comparative Example 2 2.2 8.1 Comparative Example 3 2.2 5.9 Table 3. Changes in TBARS values ​​during storage (mg MDA / kg) Group Storage for 0 days Store for 30 days Example 1 0.12 0.57 Example 2 0.11 0.52 Example 3 0.13 0.64 Comparative Example 1 0.13 1.02 Comparative Example 2 0.15 1.38 Comparative Example 3 0.13 0.91

[0028] Results analysis: As can be seen from Table 1, this invention avoids the shortcomings of narrow antibacterial spectrum of preservatives by synergistically combining active polypeptide LEPYI with tea polyphenols, ε-polylysine, nisin, and vitamin C. At the same time, the targeted screening and use of LEPYI fundamentally solves the problems of unstable polypeptide activity and weak synergistic effect against Gram-negative bacteria.

[0029] As can be seen from Tables 2 and 3, this invention, through the precise combination of LEPYI with four traditional preservation ingredients, combined with the synergistic process of vacuum tumbling, two-stage low-temperature slow cooking and rapid cooling, breaks through the bottleneck of short shelf life and rapid deterioration of quality in existing technologies for pre-prepared beef dishes.

[0030] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent implementations or modifications made in accordance with the present invention should be covered within the scope of protection of the present invention.

Claims

1. A preservative liquid, characterized in that, The preservative solution, by weight-volume percentage, contains 0.1% to 0.3% tea polyphenols, 0.01% to 0.05% ε-polylysine, 0.005% to 0.02% nisin, 0.03% to 0.1% vitamin C, and 0.05% to 0.2% active polypeptides; the amino acid sequence of the active polypeptides is LEPYI.

2. The preservative liquid according to claim 1, characterized in that, The preservation solution, by weight and volume percentage, consists of 0.2% tea polyphenols, 0.025% ε-polylysine, 0.01% nisin, 0.07% vitamin C, and 0.1% active polypeptide LEPYI.

3. A method for preserving the juices and freshness of pre-cooked beef dishes, characterized in that, Includes the following steps: S1: Place the cut beef chunks in a vacuum tumbler, add the preservative liquid as described in claim 1 or 2, control the vacuum degree to -0.08~-0.06 MPa, and tumble at 0~4℃ for 10~20 minutes to allow the preservative liquid to penetrate the beef tissue evenly. S2: Remove the beef, drain off excess liquid, put it into a cooking bag, vacuum the bag until the vacuum level inside the bag is below -0.095 MPa, and heat seal it. S3: In the first stage, the vacuum-packed beef is heated at 58~62℃ for 25~35 minutes; in the second stage, the temperature is increased to 70~75℃ and heated for another 35~45 minutes. S4: After slow cooking, quickly immerse the bag of beef in an ice-water mixture to cool it until the core temperature is below 4°C, and then transfer it to a cold storage at 0~4°C.

4. The method for preserving and locking in the juices of prepared beef dishes according to claim 3, characterized in that, In step S1, the ratio of the preservative liquid to the beef chunks is 1:0.3 to 1:0.

8.

5. The method for preserving and locking in the juices of prepared beef dishes according to claim 3, characterized in that, In step S1, the preservative solution is introduced into the beef tissue by vacuum tumbling or multi-needle vacuum injection.

6. A pre-cooked beef dish, characterized in that, It is prepared using the juice-locking and preservation method according to any one of claims 3 to 5.