Mutton quality improving and echelon processing and storing method and system

Abstract

The invention belongs to but is not limited to the technical field of agricultural product storage, and discloses a mutton quality improving and gradient processing storage method which comprises the steps of cold storage, ice temperature and freezing storage. A modified atmosphere fresh-keeping packaging method; applying a natural biological fresh-keeping technology; and carrying out full-chain storage management. Through comprehensive application of cold storage, ice temperature and freezing in combination with a modified atmosphere fresh-keeping packaging technology, the storage time of the mutton is remarkably prolonged, and meanwhile the excellent quality of the mutton is kept. The cold storage and ice temperature technology effectively inhibits the growth and enzymatic reaction of microorganisms, delays the oxidation process of the mutton, and maintains the color, texture and flavor of the mutton; the quick freezing and ultrasonic unfreezing technology is adopted, so that the damage to the cell structure of the mutton in the freezing and unfreezing process is reduced to the maximum extent. By optimizing the unfreezing process, juice loss is reduced, the unfrozen mutton still keeps good texture and taste, and the problem of quality loss in a traditional method is solved.

Description

Technical Field

[0001] The present invention belongs to but is not limited to the technical field of agricultural product storage, and in particular relates to a method and system for improving the quality of mutton and performing cascade processing and storage. Background Art

[0002] At present, my country's mutton production is about 5 million tons, ranking first in the world; Shaanxi Province's mutton production is 96,000 tons, and Yulin City's mutton accounts for more than 50% of the province. The problem of quality deterioration during mutton storage: In traditional mutton storage methods, factors such as temperature fluctuations, improper humidity control, and long-term storage lead to quality deterioration of mutton, such as hardening of meat, dehydration, dull color, and decreased flavor. This not only affects the taste and nutritional value of mutton, but also shortens its shelf life. The problem of quality loss of mutton during freezing and thawing: Freezing treatment is a common method to extend the storage period of mutton, but during the freezing and thawing process, mutton cells are easily broken due to the formation of ice crystals, resulting in loss of juice and deterioration of texture after thawing. This quality loss is difficult to avoid in traditional freezing and thawing methods. The problem of poor preservation effect during mutton storage: Conventional preservation technology is difficult to effectively inhibit the growth of microorganisms and delay the oxidation process, resulting in mutton being easy to deteriorate during storage and having a short shelf life. In addition, the use of chemical preservatives poses safety risks and is difficult to meet the food safety and health requirements of modern consumers.

[0003] Through the above analysis, the problems and defects of the prior art are as follows:

[0004] The problem of quality deterioration of mutton during storage: In traditional mutton storage methods, factors such as temperature fluctuations, improper humidity control, and long-term storage lead to quality deterioration of mutton, such as hardening of the meat, dehydration, dull color, and decreased flavor. This not only affects the taste and nutritional value of mutton, but also shortens its storage period.

[0005] The problem of quality loss of mutton during freezing and thawing: Freezing is a common method to extend the storage period of mutton, but during the freezing and thawing process, mutton cells are easily broken due to ice crystal formation, resulting in loss of juice and deterioration of texture after thawing. This quality loss is difficult to avoid in traditional freezing and thawing methods.

[0006] The problem of poor preservation effect during mutton storage: Conventional preservation technology is difficult to effectively inhibit the growth of microorganisms and delay the oxidation process, resulting in mutton being easily spoiled during storage and having a short shelf life. In addition, the use of chemical preservatives brings safety risks and is difficult to meet the requirements of modern consumers for food safety and health. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a method and system for improving the quality of mutton and for cascade processing and storage.

[0008] The present invention is achieved by providing a method for improving the quality of mutton and processing and storing it in stages, the method comprising:

[0009] Step 1. Refrigerated, iced, or frozen storage methods:

[0010] (a) Classify fresh mutton according to different parts and expected storage time;

[0011] (b) For mutton that needs to be stored for a short period of time, refrigeration (0°C to 4°C) or ice storage (-1°C to 0°C) should be used to maintain the tenderness and best taste of the meat;

[0012] (c) For mutton that needs to be stored for a long time, frozen storage (below -18°C) is used to ensure that the meat is not damaged during the freezing process and to maintain its nutritional value and flavor to the greatest extent.

[0013] Step 2. Modified atmosphere fresh-keeping packaging method:

[0014] (a) Before storage and transportation, the mutton is packaged in a controlled atmosphere fresh-keeping package;

[0015] (b) The gas composition in the package is controlled to a ratio of low oxygen (1-5%), high carbon dioxide (20-30%), and nitrogen (65-79%) to slow down the oxidation process of the mutton and inhibit the growth of microorganisms;

[0016] (c) Modified atmosphere packaging materials should choose composite films with high barrier properties and good mechanical properties to ensure the sealing and durability of the packaging.

[0017] Step 3. Application of natural biological preservation technology:

[0018] (a) Spraying or soaking the surface of mutton with a natural biological fresh-keeping liquid, wherein the fresh-keeping liquid is composed of plant extracts (such as rosemary, tea polyphenols), fermentation products or natural antioxidants.

[0019] Preparation of preservative: using kiwi polyphenol, apple polyphenol, tea polyphenol natural biological preservatives to mix and prepare the preservative solution;

[0020] Mutton soaking: Soak the mutton in the preservative solution for 30 minutes to 1 hour to ensure that the preservative evenly penetrates into the meat;

[0021] Step 4. Full chain storage management:

[0022] (a) Establish a full-chain storage management system from slaughtering, primary processing, packaging, storage, transportation to terminal sales;

[0023] (b) Real-time monitoring and recording of key storage parameters such as temperature, humidity, and gas composition are performed at each stage to ensure the stability of the storage environment.

[0024] Through these detailed steps, the present invention can comprehensively improve the quality of mutton, extend its storage period, and ensure consistency and efficiency in the storage management process throughout the supply chain.

[0025] Further, the refrigerated, ice temperature, and frozen storage method:

[0026] (1) Refrigerated storage

[0027] Temperature control: Store fresh lamb in a refrigerated environment at 0°C to 4°C;

[0028] Humidity control: Keep the relative humidity of the storage environment between 85% and 90% to prevent the surface of the mutton from drying out;

[0029] Storage time: At this temperature, the lamb can be stored for 7 to 10 days, during which time the color, smell and texture of the lamb should be checked regularly.

[0030] (2) Ice temperature storage

[0031] Temperature control: Store the lamb at -1°C to 1°C, using the ice temperature environment to inhibit the growth of microorganisms and delay enzymatic reactions;

[0032] Humidity control: Maintain ambient humidity between 90% and 95% to reduce dehydration and weight loss;

[0033] Storage time: Under ice temperature conditions, the storage period of mutton can be extended to 15 days, and its flavor and nutrients are well preserved;

[0034] (3) Frozen storage

[0035] Rapid freezing: The lamb is quickly frozen to below -18°C to minimize the damage to the cell structure by ice crystals;

[0036] Thawing method: Use ultrasonic thawing method to reduce the loss of juice during the thawing process and maintain the texture and nutrients of the mutton; the thawing temperature is controlled at 4°C, and slow thawing method is used to ensure uniform thawing.

[0037] Further, the modified atmosphere fresh-keeping packaging method:

[0038] Packaging material selection: Choose a multi-layer composite film material with good barrier properties, which can effectively isolate oxygen and moisture and delay the oxidation and deterioration of mutton;

[0039] Gas composition control: according to the storage time and environmental conditions of mutton, the gas ratio in the package is adjusted; the typical gas conditioning formula is 70% nitrogen + 30% carbon dioxide, or an appropriate amount of oxygen is added to maintain the bright red color of mutton;

[0040] Packaging and sealing: Using vacuum packaging technology, the mutton is placed in a modified atmosphere package, vacuumed and filled with preset gas, and then heat-sealed to ensure the airtightness of the package.

[0041] Furthermore, the natural biological preservation technology is applied to:

[0042] Preparation of preservative: using kiwi polyphenol, apple polyphenol, tea polyphenol natural biological preservatives, mixing in a certain proportion to prepare a preservative solution;

[0043] Mutton soaking: Soak the mutton in the preservative solution for 30 minutes to 1 hour to ensure that the preservative evenly penetrates into the meat;

[0044] Air drying: After soaking, air dry the mutton at a temperature between 4°C and 8°C for 30 minutes to 1 hour.

[0045] Furthermore, the whole chain storage management:

[0046] Temperature and humidity monitoring: During the entire storage process, intelligent temperature and humidity monitoring equipment is used to monitor environmental parameters in real time, and the temperature and humidity are automatically adjusted through the data feedback system to ensure stable storage conditions;

[0047] Regular quality testing: every three days, the quality of the stored mutton is tested for microbiological indicators, moisture content, color and smell to ensure that the quality of the mutton meets the requirements;

[0048] Storage time adjustment.

[0049] Furthermore, the storage time is adjusted: according to the storage conditions and quality test results of the mutton, the storage time and method are adjusted, such as extending the ice temperature storage period or performing frozen storage in advance.

[0050] Further, the following steps are included:

[0051] 1) Intelligent storage module:

[0052] (a) Based on intelligent sensing technology, real-time monitoring of the temperature, humidity and gas composition of the mutton storage environment;

[0053] 2) Intelligent packaging module:

[0054] (a) Using intelligent modified atmosphere packaging equipment, the gas ratio in the package is automatically adjusted according to the type, part and storage requirements of the mutton, so as to achieve precise modified atmosphere fresh-keeping packaging;

[0055] (b) The system monitors the gas composition in the package in real time through sensors, and automatically issues an alarm or adjusts gas injection when it detects changes in gas composition or failure of the package seal to ensure the effectiveness and sealing of the package.

[0056] Further, the following steps are included:

[0057] 1) Intelligent fresh-keeping module:

[0058] (a) Through the intelligent spraying system, the appropriate amount of natural biological preservative liquid is automatically selected and applied according to the number and type of bacterial colonies on the surface of the mutton to ensure the accuracy and effectiveness of the preservation treatment;

[0059] (b) The preservation module interacts with the storage and packaging modules to collaboratively optimize the overall preservation and storage strategy of mutton.

[0060] 2) Intelligent full-chain management module:

[0061] (a) Using the Internet of Things (IoT) technology, establish an intelligent management system for the entire chain from slaughtering, primary processing, packaging, storage, transportation to terminal sales, and conduct real-time monitoring and data collection for each link;

[0062] (b) The system automatically identifies key control points in the storage chain through big data analysis, conducts risk assessment and timely warning, realizes dynamic adjustment and optimization management, and ensures that the quality of mutton is always maintained in the best condition;

[0063] (c) Through the intelligent management platform, storage and management data of each link are uploaded to the cloud for unified management and analysis, and quality traceability reports are generated to ensure the transparency and efficiency of the entire storage process.

[0064] These intelligent methods further optimize and automate the entire process of mutton quality improvement and tiered processing and storage by introducing advanced sensors, Internet of Things and big data technologies, significantly improving the efficiency, accuracy and reliability of the system.

[0065] Another object of the present invention is to provide an intelligent mutton storage management system for implementing the above-mentioned mutton quality improvement and tiered processing and storage method, the intelligent mutton storage management system comprising:

[0066] Storage unit: used to control the temperature and humidity conditions according to the storage requirements of mutton. The storage unit is equipped with a temperature sensor and a humidity sensor to monitor and automatically adjust the storage environment in real time to ensure the quality of mutton under different storage methods;

[0067] Modified atmosphere packaging unit: used for modified atmosphere fresh-keeping packaging of mutton. The packaging unit is equipped with a gas composition control system that can accurately adjust the ratio of oxygen, carbon dioxide and nitrogen in the package, and uses a high-barrier composite film for packaging to delay the oxidation process and inhibit the growth of microorganisms;

[0068] Fresh-keeping treatment unit: including a natural biological fresh-keeping liquid spraying or soaking device, which automatically adjusts the concentration and application amount of the fresh-keeping liquid according to the microbial load on the surface of the mutton to achieve the best fresh-keeping effect;

[0069] Full-chain management unit: used to monitor and record the entire process from slaughtering, primary processing, packaging, storage to terminal sales, including real-time data collection and analysis of key storage parameters such as temperature, humidity, and gas composition, to ensure the quality and freshness of mutton throughout the supply chain.

[0070] Furthermore, the intelligent mutton storage management system includes:

[0071] Refrigerated storage module: equipped with intelligent temperature and humidity controller, used to store mutton in an environment of 0℃ to 4℃ and maintain a relative humidity of 85% to 90%. The system automatically monitors and adjusts the storage environment to ensure that the mutton maintains the best quality during the refrigerated period of 7 to 10 days;

[0072] Ice storage module: used to store mutton in an ice temperature environment of -1°C to 1°C. The module is equipped with a high-precision temperature and humidity control system that can maintain the ambient humidity between 90% and 95%, extending the storage period of mutton to 15 days while maintaining its flavor and nutrients;

[0073] Frozen storage module: equipped with rapid freezing equipment, which can reduce the temperature of mutton to below -18℃ in a short time to minimize the damage of ice crystals to the cell structure; the module is also equipped with an ultrasonic thawing system, which can evenly thaw the mutton at 4℃, reduce juice loss and maintain texture and nutrients;

[0074] Intelligent monitoring module: used to monitor, record and optimize all storage conditions of the refrigeration, ice temperature and freezing storage modules in real time, and realize intelligent decision-making of storage management through data analysis to ensure the high quality of mutton throughout the storage process.

[0075] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0076] First, based on traditional mutton processing and by-product treatment, the present invention innovates the process around the three aspects of "fresh mutton + cooked mutton + mutton by-products" to form a mutton quality improvement and tiered processing and storage technology system.

[0077] In order to address the issues of mutton preservation and quality, we have innovatively carried out research on the effects of low-temperature storage technology, controlled atmosphere fresh-keeping packaging technology, natural biological preservation technology, and scientific repeated freezing and thawing technology on the quality and freshness of mutton, extending the storage period to more than 15 days.

[0078] In order to address issues such as the preservation of high-quality mutton, we have carried out innovative research on mutton slaughtering, cutting and grading technology, and mutton engineering processing technology, and screened the optimal nutritional and safe tiered processing technology to maximize the preservation of nutritional quality, improve food quality, and reduce harmful substances.

[0079] In response to the problem of insufficient comprehensive utilization of mutton by-products, we have carried out innovative green research, applied irradiation, green packaging technology, ultrasound-assisted enzymatic hydrolysis, ultrafine grinding and spray drying technology, and developed a series of by-product products.

[0080] 1. Significantly extend the shelf life of mutton and maintain its quality:

[0081] Through the comprehensive application of refrigeration, ice temperature, freezing and modified atmosphere fresh-keeping packaging technology, the present invention significantly prolongs the storage time of mutton while maintaining the excellent quality of mutton. Refrigeration and ice temperature technology effectively inhibit the growth of microorganisms and enzymatic reactions, delay the oxidation process of mutton, and maintain the color, texture and flavor of mutton.

[0082] 2. Reduce quality loss during freezing and thawing:

[0083] The use of rapid freezing and ultrasonic thawing technology minimizes the damage to the mutton cell structure during the freezing and thawing process. By optimizing the thawing process, the loss of juice is reduced, so that the thawed mutton still maintains a good texture and taste, solving the quality loss problem in traditional methods.

[0084] 3. Improve the preservation effect and food safety:

[0085] The use of natural biological preservatives (such as kiwi polyphenols, apple polyphenols, and tea polyphenols) to process mutton effectively slows down the growth of microorganisms and oxidation reactions, and reduces the use of chemical preservatives. Combined with modified atmosphere fresh-keeping packaging technology, it not only extends the shelf life of mutton, but also improves food safety.

[0086] 4. Achieve full-chain quality management:

[0087] Through the full-chain temperature and humidity monitoring and quality inspection system, we ensure that the mutton is always kept in the best conditions during the entire storage and transportation process to avoid quality deterioration caused by environmental factors.

[0088] In summary, the present invention effectively solves the common technical problems in the storage and processing of mutton through a series of innovative storage technologies and methods, and significantly improves the storage quality of mutton.

[0089] Second, the significant technological advances brought about by the present invention are embodied in the following aspects:

[0090] 1. Extend the storage period of mutton and keep the meat fresh:

[0091] By studying and applying advanced preservation technologies such as vacuum packaging, controlled atmosphere preservation and cold chain transportation, the present invention significantly extends the storage period of fresh mutton while maintaining the color, flavor and nutritional components of the meat.

[0092] 2. Improve the nutritional value and food safety of mutton:

[0093] The invention uses a tiered processing technology and appropriate heat treatment, pickling, drying and other processes to retain the nutrients in the mutton and enhance its edible quality. At the same time, the graded processing technology ensures the food safety of mutton of different grades during the processing.

[0094] 3. Efficiently utilize mutton processing by-products to maximize resource utilization:

[0095] The present invention systematically studies the comprehensive utilization technology of mutton processing by-products, and transforms by-products such as bones, fat, and viscera that are traditionally easily wasted into high value-added products, such as collagen extraction, animal feed production, and oil refining. This innovative technology that maximizes resource utilization reduces environmental pollution,

[0096] In summary, the present invention significantly improves the quality, processing efficiency and resource utilization of mutton through the application of a series of innovative technologies, bringing comprehensive technological progress to the development of the mutton industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Figure 1 This is a flow chart of a method for improving mutton quality and processing and storing mutton in stages provided by an embodiment of the present invention;

[0098] Figure 2 It is a flow chart of a research and demonstration method for fresh mutton storage and preservation technology provided by an embodiment of the present invention;

[0099] Figure 3 This is a graph showing the change in meat color of mutton within 48 hours of maturity after slaughter provided by an embodiment of the present invention;

[0100] Figure 4 This is a graph showing changes in cooking loss of mutton within 48 hours after slaughter and maturation provided by an embodiment of the present invention;

[0101] Figure 5 This is a graph showing changes in hardness and shear force of mutton within 48 hours of post-maturation provided by an embodiment of the present invention;

[0102] Figure 6This is a graph showing changes in elasticity, viscosity and recovery of mutton within 48 hours of post-maturation provided by an embodiment of the present invention;

[0103] Figure 7 48 hours after the mutton is matured after slaughter, and the protein composition (A) and degradation degree (B) of the mutton provided by the embodiment of the present invention are shown in FIG.

[0104] Figure 8 The protein electrophoresis diagram of sarcoplasmic protein (A) and myofibrillar protein (B) of mutton within 48 hours of post-maturation provided by the embodiment of the present invention;

[0105] Fig. 9 This is a graph showing changes in TBARS values ​​of mutton within 48 hours of post-slaughter maturation provided by an embodiment of the present invention;

[0106] Fig.10 This is a graph showing changes in protein solubility within 48 hours of post-maturation mutton provided by an embodiment of the present invention;

[0107] Fig.11 This is a graph showing changes in myofibrillar protein carbonyl content within 48 hours of post-maturation mutton provided by an embodiment of the present invention;

[0108] Fig.12 This is a graph showing changes in the sulfhydryl content of myofibrillar protein within 48 hours of post-maturation mutton provided by an embodiment of the present invention;

[0109] Fig.13 is a graph showing changes in TVB-N content in mutton under four storage conditions provided in an embodiment of the present invention;

[0110] Fig.14 is a graph showing changes in eight types of biogenic ammonia content in mutton under four storage conditions provided by an embodiment of the present invention;

[0111] Fig.15 is a graph showing changes in the response intensity of mutton under four storage conditions provided by an embodiment of the present invention;

[0112] Fig.16 is a correlation coefficient matrix diagram of mutton under four storage conditions provided by an embodiment of the present invention;

[0113] Fig.17 The thermal phase diagram of the freeze-thaw temperature rise curve at the lowest temperature of -20°C provided by the embodiment of the present invention;

[0114] Fig.18 It is a thermal phase diagram of temperature rise curves of different minimum freeze-thaw temperatures provided by the embodiments of the present invention;

[0115] Fig.19 This is a graph showing changes in the loss of juice from a meat sample after multiple freeze-thaw cycles provided by an embodiment of the present invention;

[0116] Fig. 20is a graph showing changes in pH of meat samples subjected to multiple freeze-thaw cycles provided by an embodiment of the present invention;

[0117] Fig.21 is a graph showing changes in the physical properties of meat samples after multiple freeze-thaw cycles provided by an embodiment of the present invention;

[0118] Fig. 22 : is a graph showing changes in TBARS value (a) and fatty acid (b) of meat samples subjected to multiple freeze-thaw cycles provided in an embodiment of the present invention;

[0119] Fig.23 This is a diagram showing changes in the microstructure of meat-like fibers after multiple freeze-thaw cycles provided by an embodiment of the present invention;

[0120] Fig.24 1 is a graph showing changes in amino acid content (a) and essential amino acid ratio (b) of meat samples subjected to multiple freeze-thaw cycles provided in an embodiment of the present invention;

[0121] Fig.25 is a graph showing changes in the physical properties of mutton during freezing and thawing provided by an embodiment of the present invention;

[0122] Fig.26 is a graph showing changes in TBARS values ​​of mutton during freezing and thawing provided by an embodiment of the present invention;

[0123] Fig. 27 This is a PCA spectrum diagram of electronic nose detection of stewed mutton provided by an embodiment of the present invention;

[0124] Fig.28 This is a radar chart of electronic nose detection of stewed mutton provided by an embodiment of the present invention;

[0125] Fig.29 This is a flow chart of a detailed method for improving the quality of mutton and for cascade processing and storage provided by an embodiment of the present invention;

[0126] Fig.30 It is a structural block diagram of a mutton quality improvement and cascade processing and storage system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0127] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0128] like Figure 1 As shown, the embodiment of the present invention provides a method for improving the quality of mutton and for cascade processing and storage, comprising:

[0129] S101, refrigerated, ice temperature, and frozen storage methods;

[0130] S102, modified atmosphere fresh-keeping packaging method;

[0131] S103, Application of natural biological preservation technology;

[0132] S104, full-chain storage management.

[0133] The present invention provides a method for improving the quality of mutton and for cascade processing and storage. Through a series of optimized storage methods and processing steps, the high quality and freshness of mutton in the entire supply chain are ensured. The following is the detailed working principle of the method:

[0134] 1. Refrigerated, ice temperature, frozen storage methods:

[0135] After the mutton is processed, the appropriate storage method is first selected according to its different parts and intended uses. For parts that are processed in a short period of time, refrigeration or ice temperature storage is used to maintain the freshness and flavor of the meat. For parts that need to be stored for a long time, frozen storage is used to prevent the meat from deteriorating. Through this hierarchical storage method, the nutritional components and sensory quality of the mutton are retained to the greatest extent.

[0136] 2. Modified atmosphere fresh-keeping packaging method:

[0137] In order to further extend the shelf life of mutton during storage and transportation, the present invention adopts modified atmosphere fresh-keeping packaging technology. During the packaging process, by controlling the proportion of gas components in the package, such as reducing the oxygen concentration and increasing the content of carbon dioxide or nitrogen, the oxidation process of mutton is effectively slowed down, the growth of microorganisms is inhibited, thereby maintaining the freshness and color of the meat and extending the shelf life of the product.

[0138] 3. Application of natural biological preservation technology:

[0139] In order to avoid the influence of chemical preservatives on the quality of mutton, the present invention introduces natural biological preservation technology. By spraying or soaking the surface of mutton with naturally extracted biological preservative liquid, such as plant extracts or fermentation products, these natural ingredients can effectively inhibit the growth of bacteria and mold, reduce fat oxidation, and prevent meat corruption.

[0140] 4. Full chain storage management:

[0141] The invention emphasizes full-chain storage management, and strictly controls storage conditions and management processes in every link from slaughter to final sales. By real-time monitoring of key parameters such as temperature and humidity, it ensures that the mutton in each link is in the best storage state. The refined management of the entire chain can minimize the quality loss during the storage process and ensure that the mutton remains of high quality when it reaches the hands of consumers.

[0142] Through these optimized storage and processing methods, the present invention provides a systematic mutton quality improvement solution to ensure the quality and safety of mutton throughout the entire supply chain.

[0143] The embodiments of the present invention provide refrigerated, ice temperature, and frozen storage methods:

[0144] (1) Refrigerated storage

[0145] Temperature control: Store fresh lamb in a refrigerated environment at 0°C to 4°C;

[0146] Humidity control: Keep the relative humidity of the storage environment between 85% and 90% to prevent the surface of the mutton from drying out;

[0147] Storage time: At this temperature, the lamb can be stored for 7 to 10 days, during which time the color, smell and texture of the lamb should be checked regularly.

[0148] (2) Ice temperature storage

[0149] Temperature control: Store the lamb at -1°C to 1°C, using the ice temperature environment to inhibit the growth of microorganisms and delay enzymatic reactions;

[0150] Humidity control: Maintain ambient humidity between 90% and 95% to reduce dehydration and weight loss;

[0151] Storage time: Under ice temperature conditions, the storage period of mutton can be extended to 15 days, and its flavor and nutrients are well preserved;

[0152] (3) Frozen storage

[0153] Rapid freezing: The lamb is quickly frozen to below -18°C to minimize the damage to the cell structure by ice crystals;

[0154] Thawing method: Use ultrasonic thawing method to reduce the loss of juice during the thawing process and maintain the texture and nutrients of the mutton; the thawing temperature is controlled at 4°C, and slow thawing method is used to ensure uniform thawing.

[0155] The embodiment of the present invention provides a modified atmosphere fresh-keeping packaging method:

[0156] Packaging material selection: Choose a multi-layer composite film material with good barrier properties, which can effectively isolate oxygen and moisture and delay the oxidation and deterioration of mutton;

[0157] Gas composition control: according to the storage time and environmental conditions of mutton, the gas ratio in the package is adjusted; the typical gas conditioning formula is 70% nitrogen + 30% carbon dioxide, or an appropriate amount of oxygen is added to maintain the bright red color of mutton;

[0158] Packaging and sealing: Using vacuum packaging technology, the mutton is placed in a modified atmosphere package, vacuumed and filled with preset gas, and then heat-sealed to ensure the airtightness of the package.

[0159] The embodiment of the present invention provides the application of natural biological preservation technology:

[0160] Preparation of preservative: using kiwi polyphenol, apple polyphenol, tea polyphenol natural biological preservatives, mixing in a certain proportion to prepare a preservative solution;

[0161] Mutton soaking: Soak the mutton in the preservative solution for 30 minutes to 1 hour to ensure that the preservative evenly penetrates into the meat;

[0162] Air drying: After soaking, air dry the mutton at a temperature between 4°C and 8°C for 30 minutes to 1 hour.

[0163] The embodiment of the present invention provides full-chain storage management:

[0164] Temperature and humidity monitoring: During the entire storage process, intelligent temperature and humidity monitoring equipment is used to monitor environmental parameters in real time, and the temperature and humidity are automatically adjusted through the data feedback system to ensure stable storage conditions;

[0165] Regular quality testing: every three days, the quality of the stored mutton is tested for microbiological indicators, moisture content, color and smell to ensure that the quality of the mutton meets the requirements;

[0166] Storage time adjustment.

[0167] The embodiment of the present invention provides storage time adjustment: according to the storage conditions and quality test results of mutton, the storage time and method are adjusted, such as extending the ice temperature storage period or performing frozen storage in advance.

[0168] like Fig.30 As shown, the embodiment of the present invention provides a mutton quality improvement and cascade processing and storage system, comprising:

[0169] Storage module, used for storage by refrigeration, ice temperature, and frozen storage methods;

[0170] A packaging module, used for packaging by a modified atmosphere fresh-keeping packaging method;

[0171] A fresh-keeping module, used to preserve freshness through natural biological fresh-keeping technology;

[0172] Management module, used for storage management of the entire chain.

[0173] Example 1: Storage of fresh mutton in supermarkets

[0174] A large supermarket needs to store high-quality fresh mutton for a long time to ensure that the mutton on the shelves can remain fresh and safe.

[0175] Storage method application:

[0176] 1. Refrigerated storage:

[0177] Operation: The supermarket stores the purchased fresh lamb in a cold room at 0℃ to 4℃ and the humidity is controlled at 85% to 90%. The lamb is stored in the cold room for 7 days, and the color, smell and texture of the lamb are checked every day during this period.

[0178] Results: Lamb meat retained good color and texture over 7 days of refrigerated storage.

[0179] 2. Modified atmosphere fresh-keeping packaging:

[0180] Operation: During the cold storage process, some mutton is pre-packaged and packed using modified atmosphere packaging technology, with the gas composition of the package being 70% nitrogen + 30% carbon dioxide. After packaging, the mutton is vacuum-sealed and stored in the cold storage area.

[0181] Results: Modified atmosphere packaging delayed the oxidation process of mutton, maintaining the bright red color and freshness of the mutton. After 10 days of storage, the mutton still maintained a high quality.

[0182] 3. Natural biological preservation technology:

[0183] Operation: In order to improve the preservation effect of mutton, part of the mutton was soaked in kiwi polyphenols and tea polyphenols solution before packaging, then air-dried, and finally packaged in a controlled atmosphere.

[0184] Results: Lamb treated with natural biological preservatives maintained good color and texture after 14 days of storage.

[0185] By implementing the above storage method, supermarkets are able to provide high-quality fresh lamb on the shelves for a long time.

[0186] Example 2: Frozen mutton storage in a mutton processing plant

[0187] The mutton products produced by a mutton processing plant need to be exported overseas, and the mutton is required to maintain good quality during transportation and storage. Especially during long-term frozen storage, the quality of the mutton must not be affected after thawing.

[0188] 1. Freezer storage:

[0189] Operation: The mutton processing plant quickly freezes the slaughtered mutton to below -18°C to minimize the damage of ice crystals to the cell structure. The frozen mutton is stored in a -18°C freezer.

[0190] Results: The freezing process preserved the quality of mutton well during storage and transportation, making it suitable for long-distance transportation and long-term storage.

[0191] 2. Thawing process:

[0192] Operation: Before exporting to overseas customers, the factory conducted thawing experiments on some frozen mutton samples, using ultrasonic thawing method, controlling the thawing temperature at 4°C, and thawing slowly to ensure uniformity.

[0193] Results: Through ultrasonic thawing treatment, the lamb still maintained good texture and flavor after thawing, and less juice was lost.

[0194] 3.Quality Control:

[0195] Operation: During the entire frozen storage and transportation process, intelligent temperature and humidity monitoring equipment is used to monitor the environmental parameters of the freezer and transportation process in real time, and the temperature and humidity are automatically adjusted through the data feedback system.

[0196] Result: Thanks to strict temperature and humidity monitoring, the exported mutton still maintains a high quality after long-distance transportation.

[0197] By implementing the above storage and thawing method, the mutton processing plant can effectively maintain the quality of mutton during frozen storage and long-distance transportation.

[0198] like Fig.29 As shown, the embodiment of the present invention provides a detailed method for improving the quality of mutton and cascade processing and storage, the method comprising:

[0199] S1: Research on storage and preservation technology of fresh mutton;

[0200] S2: Research on nutritional safety cascade processing technology of mutton;

[0201] S3: Research on comprehensive utilization of mutton processing by-products.

[0202] The mutton quality improvement and tiered processing and storage method provided by the present invention systematically improves the mutton quality and optimizes the processing process through a series of technical research and demonstration, thereby achieving efficient utilization of mutton.

[0203] S1: Research and demonstration of storage and preservation technology for fresh mutton

[0204] First, in order to preserve fresh mutton, we studied preservation technologies such as vacuum packaging, atmosphere conditioning, and cold chain transportation to extend the storage period of mutton and maintain its freshness. By analyzing the impact of different storage conditions on the quality of mutton, we optimized the temperature, humidity, and gas composition in the storage environment to ensure that the mutton can maintain its original color, flavor, and nutrients to the greatest extent during the storage process. In the demonstration phase, we applied the laboratory research results in the actual production environment to verify the feasibility and actual effect of the technology, and made corresponding adjustments to achieve the best preservation effect.

[0205] S2: Research and demonstration of mutton nutritional safety tiered processing technology

[0206] This step aims to study the grading and processing technology of mutton, and to grade mutton through different processing techniques to improve its nutritional value and safety. The research content includes how to retain the nutrients in mutton (such as protein, vitamins, etc.) during the processing, and to improve the edible quality of mutton through appropriate heat treatment, pickling, drying and other processes. In the demonstration stage, the research results were applied to the production line to process mutton of different qualities in stages, and to ensure that the processed mutton meets the requirements by testing and analyzing the food safety indicators of each processing link.

[0207] S3: Research on comprehensive utilization of mutton processing by-products

[0208] During the processing of mutton, a large number of by-products are produced, such as bones, fat, and viscera. This step studies how to efficiently utilize these by-products and convert them into high-value-added products, such as extracting collagen, preparing animal feed, and refining oils. By optimizing the processing technology and extraction technology, the utilization rate of by-products can be maximized, and waste and environmental pollution can be reduced.

[0209] Comprehensive effect:

[0210] Through the research and demonstration of the above steps, the quality improvement and optimal utilization of resources in the entire mutton processing chain can be achieved.

[0211] like Figure 2 As shown, the S1 specifically includes:

[0212] S11: Conduct research on the effects of three low-temperature storage technologies, namely, refrigeration, ice temperature and freezing, on the quality and freshness of mutton;

[0213] S12: Conduct research on the effects of vacuum, nitrogen, carbon dioxide and modified atmosphere packaging technologies on the quality and freshness of mutton;

[0214] S13: Conduct research on the effects of natural biological preservation technologies such as kiwifruit polyphenols, apple polyphenols, and tea polyphenols on the quality and freshness of mutton;

[0215] S14: Combine air thawing, hydrostatic thawing, ultrasonic thawing and other technologies to study the effects of repeated freezing and thawing on the quality of mutton, and select the best thawing method for Yulin mutton;

[0216] S15: Demonstrate and apply mutton storage and preservation technology to sheep farmers, slaughterhouses, and catering companies to improve the shelf life and freshness of mutton.

[0217] The S2 specifically includes:

[0218] S21: Conduct research on mutton slaughtering, cutting and grading, mutton engineering processing technology and other tiered processing technologies;

[0219] S22: Screen out the best nutritional and safe processing technology for Yulin specialty mutton such as Shaanxi white cashmere goat and Hu sheep;

[0220] S23: Maintain nutritional quality to the maximum extent, improve edible quality, reduce harmful substances, and form a mutton nutritional safety echelon processing technology system;

[0221] S24: Comprehensively apply mutton tiered processing technology to develop new Chinese-style deep-processed mutton products such as marinated, grilled, and air-dried, and diversify mutton product categories.

[0222] The S3 specifically includes:

[0223] S31: Carry out comprehensive utilization of mutton processing by-products such as sheep blood, sheep hooves, sheep intestines, sheep hearts, sheep livers, and sheep tripes;

[0224] S32: Optimizing the application of vacuum tumbling, smell removal, and quantitative braising in the braising process of sheep by-products, the application of green irradiation sterilization and green packaging technology, the research on the preparation of collagen peptides and sheep plasma protein peptides by ultrasound-assisted enzymatic hydrolysis, the application of spray drying to prepare sheep blood powder and ultrafine grinding to prepare sheep bone powder;

[0225] S33: Create Yulin’s characteristic mutton processing by-products.

[0226] The embodiment of the present invention provides a mutton quality improvement and cascade processing and storage technology research system based on the mutton quality improvement and cascade processing and storage method, and the system specifically includes:

[0227] Fresh-keeping technology research module, used for research and demonstration of storage and preservation technology for fresh mutton;

[0228] The processing technology research module is connected with the preservation technology research module to study and demonstrate the nutritional safety cascade processing technology of mutton;

[0229] The comprehensive utilization research module is connected with the processing technology research module and is used for the research and demonstration of comprehensive utilization of mutton processing by-products.

[0230] Relevant evidence of the technical effects achieved by the embodiments of the present invention.

[0231] 1. Research on technology to improve the quality of mature mutton after slaughter

[0232] First, nine healthy male goats aged 1.5 years (uncastrated, weighing 35±2kg) were selected and slaughtered according to commercial slaughter standards. The longissimus dorsi muscles on both sides were collected immediately after slaughter. After removing visible fat and connective tissue, the longissimus dorsi muscles were placed in an ice box (-2~1℃) and transported to the laboratory within 5 hours. The meat samples were placed in a 4℃ refrigerator for 0, 12, 24, and 48 hours of maturation to determine the meat quality characteristics. Each group of samples contained 3 replicates.

[0233] 1.1 Changes in meat color, texture, cooking loss, and shear stress during post-slaughter maturation

[0234] Changes in meat color during post-slaughter maturation Figure 3 The color change of goat longissimus dorsi muscle during the 48h post-slaughter maturation process is shown in Figure 3 As shown in the figure. At the four time points measured, a* and b* values ​​increased with time, L* value reached its maximum value at 24h, and Hue and Chroma values ​​reached their highest and lowest values ​​at 12h, respectively. The changes in these indicators indicate that the meat color quality continues to improve during the 48h post-slaughter maturation process.

[0235] Changes in cooking loss of goat longissimus dorsi muscle during 48 h post-slaughter maturation Figure 4 As shown. Among the four time points measured, the cooking loss at 0h was the smallest (30.1%), and between 12h and 48h, the cooking loss was stable at around 35%. The cooking loss of fresh meat reflects the water holding capacity of the meat. The higher the cooking loss, the worse the water holding capacity. After 12h, the cooking loss no longer changes significantly, indicating that the water holding capacity of meat in the short-term post-slaughter maturation process mainly changes in the first 12h.

[0236] Changes in texture and shear force of goat longissimus dorsi muscle during 48 h post-slaughter maturation Figure 5 As shown. Among the four time points measured, the hardness of fresh meat and the shear force of cooked meat reached the maximum at 12h, which were 192N and 72N respectively. Elasticity, cohesion and resilience also reached the maximum at 12h ( Figure 6 ). In general, the change trends of the five indicators are consistent, showing an increase first and then a decrease. These physical and chemical properties of mutton can indirectly reflect its palatability. It should be noted that hardness, elasticity, cohesion and resilience are characteristics of raw meat, which can reflect the appearance of raw meat, such as touch and appearance. Shear force is for cooked meat and can reflect the tenderness of meat. The larger the value, the lower the tenderness of the meat. Mutton undergoes rigor mortis during the post-slaughter maturation process. Changes in texture and shear force indicate that 12h is the time node for muscle rigidity and thawing.

[0237] 1.2 Changes in protein composition and degradation of mutton during post-slaughter maturation

[0238] The extracted goat muscle protein is mainly composed of sarcoplasmic protein and myofibrillar crude protein (which can be subdivided into purified myofibrillar protein, alkali-soluble protein, and myofibrillar matrix protein). Figure 7 . The total protein content was 25% to 26%, and the average contents of the four proteins were 78.89, 11.73, 64.73, and 102.12 mg / g meat, respectively. The sarcoplasmic protein content at 0h was about 17% higher than that at other time points, and the myofibrillar protein content at 0h was significantly higher than that at 12h and 24h. There was no significant difference in the content of alkali-soluble protein and muscle matrix protein at different maturation times. Therefore, sarcoplasmic protein and myofibrillar protein are the main proteins that change in goat muscle during the 48h maturation process.

[0239] The changes in sarcoplasmic and myofibrillar proteins are mainly protein degradation, as the color of the protein band becomes lighter, e.g. Figure 8 As shown. The molecular weights of these two types of proteins are mainly distributed in the range of 26-180 kDa. Among them, the 34-43 kDa part of sarcoplasmic protein is obviously lighter in color at 12 hours. The 56 kDa part of myofibrillar protein and the 72-100 kDa part of myofibrillar protein are obviously lighter in color at 12 hours. After 0 hours, the color of the 26-34 kDa myofibrillar protein band is obviously darker than that at 0 hours; and the total protein degradation at 12 hours is significantly lower than that at 0 hours, as shown in Figure 2. Fig. 9 The total protein degradation rate was the highest at 0h, reaching 8.27%, and the lowest at 12h, reaching 5.43%. After 12h, PI increased slowly.

[0240] 1.3 Changes in the amino acid composition of mutton during post-slaughter maturation

[0241] The relative amino acid content of goat LT muscle matured at 4°C for 48 hours is shown in Table 1. The content of aspartic acid (Asp), serine (Ser), tyrosine (Tyr) and phenylalanine (Phe) changed significantly (P<0.05), and other amino acids did not change significantly within 48 hours. In general, glutamic acid (Glu, 37.34 mg / g meat) had the highest content, followed by alanine (Ala, 29.72 mg / g meat), and proline (Pro, 4.83 mg / g meat) had the lowest content. Interestingly, the content of Asp (21.65 mg / g meat) and Ser (9.60 mg / g meat) was the lowest at 12 hours, and Tyr (26.86 mg / g meat) and Phe (24.82 mg / g meat) were the highest at 12 hours, which is consistent with the rules of rigor mortis and rigor relieving in the present invention.

[0242] Table 1 Changes in amino acid content in mutton within 48 hours after slaughter

[0243]

[0244] 1.4 Changes in lipid oxidation during post-slaughter maturation

[0245] Changes in TBARS values ​​of goat longissimus dorsi muscle during 48h post-slaughter maturation Figure 5 As shown. The TBARS value reflects the degree of lipid oxidation in meat. In the present invention, the TBARS value continued to increase from 0.523 mg / kg at 0h to 0.773 mg / kg at 48h, and the increase was significant (P<0.05). The increase rate of TBARS values ​​at 12-24h and 24-48h was similar. Compared with the increase rate at 0-12h (0.556 mg / kg), the increase rate at 12-48h was significantly increased.

[0246] 1.5 Changes in protein solubility during post-mortem maturation

[0247] Changes in protein solubility in goat longissimus dorsi muscle during 48 h post-slaughter maturation Fig.10 As shown. Protein solubility reflects the dispersion level of protein in water, which can be used to reflect the denaturation of protein and reflect the oxidation state of protein to a certain extent. The present invention measures the solubility of total protein, sarcoplasmic protein solubility and myofibrillar protein solubility. During the entire maturation process, the solubility of total protein decreased from 209.07 mg / g at 0h to 189.89 mg / g at 48h, the solubility of myofibrillar protein decreased from 141.14 mg / g at 0h to 128.63 mg / g at 48h, and the solubility of sarcoplasmic protein decreased from 67.93 mg / g at 0h to 61.26 mg / g at 48h. Among them, all three showed a significant decrease in the 0-12h maturation process, with the decreases in the solubility of total protein, myofibrillar protein and sarcoplasmic protein being 12.4%, 15.1% and 9.6%, respectively.

[0248] 1.6 Changes in the carbonyl and thiol content of myofibrillar proteins during post-mortem maturation

[0249] The carbonyl content of myofibrillar protein in goat longissimus dorsi muscle during 48h post-mortem maturation Fig.11 The carbonyl content of myofibrillar protein showed an upward trend, from 4.77nmol / mg at 0h to 0.88nmol / mg at 48h. The rate of increase was slow during 0-24h, with an amplitude of 22.9%. The rate of increase was faster during the 24-48h maturation process, with an amplitude of 50%. The thiol content of myofibrillar protein in the longissimus dorsi muscle of goats during the 48h post-slaughter maturation process is shown in Figure 2. Fig.12As shown. Thiol refers to the SH group distributed on the surface and inside of the protein. The thiol content of myofibrillar protein showed a downward trend, from 13.58nmol / mg at 0h to 10.97nmol / mg at 48h. The rate of decline was large before 12h, and the rate of decline of the thiol content in the two subsequent periods was relatively consistent. The thiol content of myofibrillar protein in the longissimus dorsi muscle of goats during the 48h post-slaughter maturation process is shown in Figure 2. Fig.12 As shown. Thiol refers to the SH group distributed on the surface and inside of the protein. The thiol content of myofibrillar protein showed a downward trend, from 13.58 nmol / mg at 0h to 10.97 nmol / mg at 48h. The decline rate was large before 12h, and the decline rate of the thiol content in the two subsequent periods was relatively consistent.

[0250] 2. Study on the quality changes, freshness identification and preservation technology of frozen, refrigerated and room temperature mutton

[0251] 2.1 Changes in TVB-N value of mutton at different storage temperatures

[0252] Four different storage conditions of mutton were simulated: frozen temperature storage (-1°C), refrigerated storage (4°C), intermediate temperature storage (10°C) and room temperature storage (25°C). The changes in TVB-N content in mutton under the four storage conditions are shown in Figure 2. Fig.13 As shown in the results, the increase of TVB-N content was associated with the extension of storage time (P<0.05). The initial TVB-N (day 0) of mutton under the four storage conditions was 1.77 mg / 100 g. At -1℃, 4℃, 10℃ and 25℃, mutton maintained the first-class freshness at 4d, 6d, 48h and 14h, respectively, while at 1℃ and 25℃, mutton deteriorated when the storage time exceeded 9d and 22h. As the storage temperature increased, the deterioration time of mutton was shortened.

[0253] 2.2 Changes in the contents of eight biogenic amines in meat products at different storage temperatures

[0254] The present invention detected 8 biogenic amines in mutton. The changes in the contents of 8 biogenic amines in mutton under 4 storage conditions are as follows: Fig.14 As shown, the increase of biogenic amines is related to the increase of storage time. Among all the biogenic amines detected by the present invention, TYR changes most significantly at -1°C, 4°C and 25°C; at 10°C, PUT has the highest content. As the storage temperature increases, the base content increases. The contents of CAD, PUT and TYR all increase with time, but the increase of TYR is the most significant and rapid. Therefore, CAD, PUT and TYR were selected as marker biogenic amines related to the freshness of mutton.

[0255] 2.3 Changes in sensor response values ​​of mutton at different storage temperatures

[0256] The sensor response value changes of mutton under four storage conditions are as follows Fig.15 As shown in the figure. Under the four storage conditions, the sensor response values ​​increased significantly with time (P<0.05), and the trend was similar to that of TVB-N and biogenic amines. At the same time, the sensor response value also increased with the increase of temperature, which was the same as the trend of TVB-N and biogenic amines.

[0257] 2.4 Correlation analysis between TVB-N value, biogenic amine content and sensor response value of mutton at different storage temperatures

[0258] The correlation coefficient matrix results of mutton under four storage conditions are shown in Fig.16 . The numbers in each box represent the correlation coefficient between two indicators; all indicators are positively correlated, so the correlation coefficient of the present invention is within the range of 0 to 1. The blocks of different colors in the figure represent the correlation coefficient. The darker the color, the lower the correlation; on the contrary, the lighter the color, the higher the correlation. In terms of color distribution, the color is lighter at 25°C, and the correlation of the five indicators is better. At -1°C, the correlation coefficient between the sensor response value and PUT is only 0.67, while the correlation coefficients between TVB-N and other indicators are all above 0.8. At 4°C, the correlation coefficients between RI and other indicators are between 0.72 and 0.9, and only the correlation coefficient between the sensor response value and TYR is greater than 0.9. At 4°C and 25°C, the correlation coefficients of the five indicators are all greater than 0.8, indicating that the correlation of the five indicators is better at 4°C and 25°C. At 25°C, the correlation coefficient between RI and PUT is the smallest, only 0.67, while the correlation coefficients between TVB-N and other indicators are all above 0.8. Under the four storage conditions, the correlation of each indicator is good, which can better reflect the freshness of mutton. Finally, a mutton freshness detection method based on fluorescence quenching technology was established.

[0259] 3. Research on freeze-thaw technology for nutritional safety of mutton

[0260] Firstly, the differential scanning calorimetry (DSC) method was used to study the changes of mutton under four freeze-thaw procedures, namely, no freeze-thaw (NFT), -20℃ freeze-thaw once (TFT1), -20℃ freeze-thaw twice (TFT2), and -80℃ freeze-thaw once (EFT1). The effects of freeze-thaw times, minimum freeze-thaw temperature, and the time between sample preparation and sample measurement on the DSC thermal enthalpy curve were analyzed. Secondly, the changes of physicochemical properties (pH, juice loss, physical properties, color, and fat oxidation) of frozen-thawed meat were analyzed under the assistance of 180W (UT180), 320W (UT320), and 400W (UT400) ultrasound, and the protein loss caused by muscle fiber damage during the freeze-thaw process was analyzed in combination with the changes in meat microstructure and amino acids. The beneficial role of different power ultrasound-assisted thawing in reducing the quality loss of meat during multiple freeze-thaw processes was explored, in order to provide a theoretical reference for actual production. Finally, in order to clarify the role of kiwifruit polyphenols in repeated freezing and thawing of mutton, the mutton was soaked in kiwifruit polyphenols and commonly used antioxidants on the market, and subjected to 1, 3, and 5 freeze-thaw treatments to study its role in improving mutton quality, delaying mutton oxidation, and extending the shelf life of frozen-thawed mutton.

[0261] 3.1 Effect of freeze-thaw cycles on DSC curves

[0262] The samples were subjected to two freeze-thaw treatments at a minimum freeze-thaw temperature of -20°C. The temperature rise curves of the 25-150°C section were as follows: Fig.17 As shown. The heating curves of the three freeze-thaw times samples all peaked at around 80℃ and 100℃. In addition, the NFT group and TFT1 group peaked at around 60℃, and the NFT group peaked at around 85℃. According to the temperature sequence of the curve peaks, the four thermal transition peaks were named peak 1, peak 2, peak 3 and peak 4, where peak 1 represents the heat flow change caused by myosin, peak 2 represents the thermal rheology caused by actin, peak 3 represents the thermal rheology caused by titin, and peak 4 represents the heat flow change caused by rapid evaporation of water. The thermal enthalpy values ​​corresponding to these thermal transition peaks are the largest in peak 4, followed by peak 2, and the smallest in peak 1.

[0263] 3.2 Effect of freeze-thaw temperature on DSC curve

[0264] The samples were subjected to no freeze-thaw (NFT), -20℃ freeze-thaw once (TFT1), and -80℃ freeze-thaw once (EFT1). The partial temperature rise curves from 25 to 150℃ are shown in Fig.18As shown. Compared with the NFT group and the TFT1 group, the peaks 1 and 2 of the EFT1 group became smaller, and the peak 4 became larger. Table 2 specifically lists the Ton, Tp and ΔH of the four peaks with the lowest freeze-thaw temperatures of -20℃ and -80℃. The ΔH1 and ΔH2 of the three freeze-thaw treatment groups decreased successively with the decrease of the lowest freeze-thaw temperature. The ΔH1 of the TFT1 group and the EFT1 group was 57.0% and 89.6% lower than that of the NFT group, respectively; the ΔH2 of the TFT1 group and the EFT1 group was 47.0% and 59.6% lower than that of the NFT group, respectively. This indicates that lower freeze-thaw temperatures have a greater effect on protein denaturation, and myosin is more susceptible to freeze-thaw than actin. The ΔH4 of the TFT1 group increased by 1.3% compared with the NFT group, and the ΔH4 of the EFT1 group increased by 15.6% compared with the NFT group, indicating that lower freeze-thaw temperatures reduce the loss of water during the freezing and thawing process of mutton.

[0265] 3.3 Changes in juice loss of ultrasonically assisted thawing meat samples

[0266] Changes in juice loss after multiple freeze-thaw cycles Fig.19 As shown. In general, with the increase of freezing and thawing times, the juice loss of the five groups of meat samples showed a significant upward trend. Using the linear fitting trend line, it was found that the increase rates of juice loss of LT and W compared with the initial samples were 1.31% and 0.90%, while the increase rates of UT400, UT320 and UT180 ultrasonic treatment were 1.57%, 1.15% and 0.93% respectively compared with the initial samples. It can be seen that ultrasound increased juice loss to a certain extent, especially the juice loss of UT400 and UT320 groups after 3 freezing and thawing was significantly higher than that of the control group (P < 0.05), while the juice loss of UT180 group increased the least after 3 freezing and thawing, and the juice loss of UT180 group was significantly lower than that of the control group after 7 freezing and thawing (P < 0.05), indicating that UT180 has the best thawing effect, which is better than high-power ultrasonic thawing and common thawing methods. It can be seen that both common thawing methods and ultrasonic thawing after multiple freeze-thaw cycles will cause loss of meat juice. The greater the power, the greater the freeze-thaw loss. However, 180W low-power ultrasonic treatment is beneficial to reducing juice loss during meat freezing and thawing.

[0267] 3.4 pH changes of meat samples thawed by ultrasound

[0268] pH changes of meat samples after multiple freeze-thaw cycles Fig. 20As shown. With the increase of freezing and thawing times, the pH of the five groups of meat samples showed a downward trend as a whole and rebounded slightly at the seventh time. The overall range of pH change was small, 5.31-5.81. The pH reduction rates of LT and WT compared with the initial samples within five freezing and thawing times were 0.071 and 0.051, while the reduction rates of UT400, UT320 and UT180 ultrasonic treatments were 0.066, 0.061 and 0.082 respectively compared with the initial samples. It can be seen that ultrasound can reduce pH to a certain extent compared with the control, especially the pH of the UT180 group was significantly lower than that of the control group after 5 freezing and thawing times (P < 0.05). Therefore, common thawing and ultrasonic thawing after multiple freezing and thawing will reduce pH to some extent, and the pH change of UT180 thawing is relatively large.

[0269] 3.5 Color changes of meat samples thawed by ultrasound

[0270] The color changes of meat samples after multiple freeze-thaw cycles are shown in Table 2. With the increase of freeze-thaw cycles, the L* and a* values ​​of the five groups of meat samples showed a decreasing trend, while the b* value gradually increased with the freeze-thaw cycles. During the multiple freeze-thaw cycles, the L* value of the ultrasound group was lower than that of the control group, especially the UT320 group had the lowest L* value (P<0.05), while the L* value of the UT180 group had no significant difference from that of the control group at freeze-thaw cycles 3 and 7 (P>0.05). During the multiple freeze-thaw processes, the a* value of the meat sample in the UT180 group was the lowest, and the a* value of the UT320 group was the highest when the freeze-thaw times were 3-7 times; with the increase in the number of freeze-thaw times, the reduction rates of the a* values ​​of LT and WT compared with the initial samples were 0.249 and 0.245, while the reduction rates of UT400, UT320 and UT18 ultrasonic treatment compared with the initial samples were 0.268, 0.212 and 0.275, respectively. It can be seen that ultrasound can reduce the a* value to a certain extent, especially the UT180 group, which had the highest reduction rate of a* value, and the a* value during the freeze-thaw period was lower than that of the control group, while UT320 ultrasound can slow down the decrease of a* value, and there is no significant difference between the UT320 group and the control group during the freeze-thaw period (P>0.05). With the increase of freezing and thawing times, the b* value of LT and WT increased at a rate of 0.295 and 0.319 compared with the initial samples, while the b* value of UT400, UT320 and UT180 treated with ultrasound increased at a rate of 0.229, 0.227 and 0.274 respectively compared with the initial samples. It can be seen that ultrasound reduces the b* value, especially the rate of UT320 group meat sample is the lowest, and the b* value during the freezing and thawing period is significantly lower than that of the control group (P<0.05); during the freezing and thawing period, the b* value of UT320 group meat sample is the lowest (P<0.05), while the b* values ​​of the other two ultrasonic treatment groups and the control group have no significant difference as a whole (P>0.05), and after 7 freezing and thawing times, the b* values ​​of UT400, UT320 and UT180 are 93%, 84% and 96% of the LT group, and 95%, 86% and 98% of the WT group, respectively.

[0271] In addition, the h° and ΔE values ​​of the five groups of meat samples gradually increased with the number of freeze-thaw cycles, indicating that the meat would fade to a certain extent during the freeze-thaw process. During the multiple freeze-thaw processes, the h° values ​​of the LT group and the UT180 group were the highest (P < 0.05), and the h° value of the UT320 group was the lowest (P < 0.05), indicating that the ultrasonic assisted thawing treatment with a power of 320 W was conducive to the stability of the meat color; while the ΔE value of the UT320 group was the highest (P < 0.05), followed by the UT180 group and the UT400 group, indicating that the ultrasonic assisted thawing could significantly affect the color of frozen and thawed meat, and because the L* value of the UT320 group was the lowest, the color change of the meat treated with ultrasound at a power of 320 W was the greatest. In short, after multiple freeze-thaw cycles, both common thawing methods and ultrasonic thawing would reduce the brightness and redness of the meat and increase its yellowness, but the ultrasonic assisted thawing treatment with a power of 320 W was conducive to the stability of the meat color, but also caused the meat color to darken, while the 180 W ultrasonic treatment would reduce the redness of the meat.

[0272] Table 2 Results of multiple freeze-thaw meat sample color determination

[0273]

[0274] 3.6 Changes in physical properties of meat thawed by ultrasound

[0275] Changes in the physical properties of meat samples after multiple freeze-thaw cycles Fig.21With the increase of freezing and thawing times, the hardness of the meat samples in the five groups showed a significant downward trend, and the hardness of the meat in the ultrasound group was lower than that in the control group. It can be seen that ultrasound reduced the hardness of meat compared with the control group, and the greater the power, the lower the hardness; especially the UT400 meat was the lowest during the freezing and thawing period (P < 0.05), while there was no significant difference in hardness between the UT320 and UT180 groups at 1, 5, and 7 freezing and thawing times (P > 0.05), indicating that the effects of ultrasonic treatment in the two groups were equivalent; at the 7th freezing and thawing time, the hardness of the UT400, UT320 and UT180 groups decreased by 47.01%, 37.02% and 7.74% respectively compared with the initial samples; and at the 7th freezing and thawing time, the hardness values ​​of UT400, UT320 and UT180 were 70%, 83% and 82% of the LT group, and 110%, 131% and 129% of the WT group, respectively. The elasticity of the meat samples in the five groups showed a decreasing trend. After the first freeze-thaw cycle, the elasticity of the LT control group was the highest (P < 0.05), while there was no significant difference in the elasticity of the meat between the ultrasound group and the WT control group after three freeze-thaw cycles (P > 0.05), and the elasticity of the UT400 group was the lowest. After seven freeze-thaw cycles, the elasticity of the UT400, UT320 and UT180 groups decreased by 22.17%, 16.17% and 18.94% respectively compared with the initial samples. After seven freeze-thaw cycles, the elasticity of the UT400, UT320 and UT180 groups was 85%, 91% and 88% of the LT group, respectively (P < 0.05), and was 97%, 104% and 101% of the WT group, respectively (P > 0.05). With the increase of the number of freeze-thaw cycles, the cohesion of the meat samples in the five groups showed an increasing trend, and the LT control group reached the highest value (0.59) after three freeze-thaw cycles, which was significantly higher than that of the ultrasound treatment group (P < 0.05). With the increase of freezing and thawing times, the resilience of the five groups of meat samples tended to decrease but stabilized overall. In particular, the ultrasonic treatment effect of the UT320 and UT180 groups was the best, and there was no significant difference between the two groups (P>0.05). At the same time, the LT control group reached the highest value (0.42) after freezing and thawing for 3 times, which was significantly higher than that of the ultrasonic treatment group (P<0.05). In short, after multiple freezing and thawing, common thawing methods and ultrasonic thawing will reduce the hardness, elasticity and resilience of meat and increase its cohesion. Compared with common thawing methods, ultrasonic assisted thawing will reduce the hardness of meat, and the higher the power, the more serious it is; ultrasonic assisted thawing does not affect the cohesion of multiple frozen and thawed meat samples, and 320W and 180W ultrasonic power assisted thawing is conducive to the stability of meat resilience.

[0276] 3.7 Changes in fat oxidation in ultrasound-assisted thawing of meat samples

[0277] Multiple freeze-thaw cycles usually accelerate fat oxidation. At the same time, free radicals and peroxides produced by fat oxidation in meat will promote protein oxidation, which will negatively affect protein structure and reduce meat quality. This paper mainly analyzes the fat oxidation of meat during multiple freeze-thaw cycles (2-thiobarbituric acid method). The results are as follows: Fig. 22 -a. The TBARS values ​​of the 5 groups of meat samples first decreased (0-3 freeze-thaw times) and then increased (3-7 freeze-thaw times) with the increase in the number of freeze-thaw times; during the multiple freeze-thaw processes, the TBARS value of the meat in the UT400 group was the highest and was significantly higher than that in the control group (P < 0.05), while there was no significant difference between the UT320 and UT180 groups and the control group (P > 0.05); after 7 freeze-thaw cycles, the TBARS values ​​of UT400, UT32 and UT180 were 106%, 92% and 88% of the LT control group, respectively, and 110%, 96% and 92% of the WT control group, respectively, indicating that ultrasonic treatment with UT320 and UT180 is beneficial to slowing down meat fat oxidation. In order to further illustrate the fat oxidation of meat with different thawing treatments, meat samples after freeze-thaw were selected to analyze their fat oxidation products (fatty acids) (such as Fig. 22 -b). Meat fat oxidation will reduce the oxidation of unsaturated fatty acids, thereby increasing the SFA content. The PUFA content of the 5 groups of meat samples was significantly lower than that of the CON group (P < 0.05), and their SFA was higher than that of the CON group, indicating that multiple freeze-thaw cycles would cause fat oxidation; compared with the control group, the meat sample of the UT400 group had the lowest PUFA and the highest SFA (P < 0.05), indicating that meat fat oxidation was aggravated; the PUFA content of the UT320 and UT180 groups was significantly higher than that of the LT control group (P < 0.05), indicating that these two groups had a certain improvement effect, and at the same time, the PUFA, MUFA and SFA content of the UT320 group had no significant difference from that of the WT control group (P > 0.05), indicating that the two groups had similar effects. In summary, the meat fatty acids were consistent with the TBARS results, indicating that after multiple freeze-thaw cycles, both common thawing methods and ultrasonic thawing would cause meat fat oxidation, especially 400W ultrasonic-assisted thawing would aggravate fat oxidation, while 320W and 180W ultrasonic-assisted thawing would help slow down this process, and the effect was equivalent to static water thawing.

[0278] 3.8 Microstructural changes of meat samples thawed by ultrasound

[0279] Changes in muscle microstructure after multiple freezing and thawing ( Fig.23), the microstructure of meat thawed by common thawing methods and ultrasonic thawing becomes less compact, loosely arranged, and discrete in shape as the number of freeze-thaw cycles increases. Under the same number of freeze-thaw cycles, the muscle fibers of the UT320, UT180, WT, LT, and UT400 groups are gradually loosely arranged and loosely structured. In particular, the structural integrity of the muscle fibers of the UT400 group and the LT control group were completely lost after 7 freeze-thaw cycles, and the dense structure was almost completely destroyed; the structural integrity of the muscle fibers of the WT control group was severely lost, and the dense structure was severely destroyed; however, the muscle fiber structure of the UT320 and UT180 groups was relatively intact. Therefore, common thawing methods and ultrasonic thawing after multiple freeze-thaw cycles will cause damage to the meat muscle fiber structure, while ultrasonic-assisted thawing treatments with powers of 320W and 180W are beneficial to maintaining the integrity of the meat muscle fiber structure, and the effect is better with 320W.

[0280] 3.9 Amino Acid Changes in Meat Samples after Ultrasound-Assisted Thawing

[0281] In order to further illustrate the loss of meat protein caused by the destruction of meat fiber structure under different freeze-thaw treatments, meat samples that had been frozen and thawed for 3 and 7 times were selected to analyze the types and contents of amino acids in their proteins ( Fig.24 -a). During multiple freeze-thaw processes, the concentration effect of juice loss will cause an increase in the amino acid content of meat. The amino acid content of the 7-LT group is the highest, indicating that the refrigerated thawing causes serious nutrient loss. Cluster analysis of amino acid types showed that the content of Glu and Pro in meat was high, while the content of Met, Thr, Tyr, His, Val, Ser, Gly, Ile and Phe was low. Among them, the content of Thr and ValIle was relatively stable with the increase of freeze-thaw times. The five groups of meat samples were divided into six categories using the contents of 16 amino acid indicators as clustering variables under the conditions of common thawing methods and ultrasonic thawing treatments: the CON and ultrasound-assisted thawing treatment groups with three freeze-thaw cycles were in the first category, with the highest amino acid nutritional quality, indicating that ultrasonic thawing was beneficial to the maintenance of the amino acid quality in meat, and the CON group was closer to the 3-UT320 group, indicating that 320W ultrasonic power was better for thawing meat; the 7-UT400, 7-WT, 3-WT and 7-UT180 groups were in the second category, with relatively poor quality, indicating that static water thawing was beneficial to the stability of the amino acid content during the freezing and thawing process of meat; 7-UT320, 3-LT and 7-LT were each in the first category, with average quality, indicating that the amino acid content of meat varied greatly during the freezing and thawing process of refrigerated thawing, which was not conducive to its quality maintenance. The clustering results were similar to those obtained in the previous analysis of physical and chemical properties, and better reflected the differences between common thawing methods and ultrasonic thawing treatments in meat that had been frozen and thawed multiple times. The changes in the proportion of essential amino acids in meat that had been frozen and thawed multiple times are shown in Figure 2. Fig.24-b, the initial EAA / TAA and EAA / NEAA values ​​were 37% and 59%, respectively. According to the high-quality protein standards stipulated by FAO / WHO, the amino acid composition EAA / TAA ratio is about 40%, and EAA / NEAA is above 60%. Therefore, the essential amino acid composition and ratio of meat before freezing and thawing are not good; when the meat is frozen and thawed three times, the composition ratio of the UT320 group becomes worse than that of the CON group, while the EAA / TAA values ​​of the other groups gradually approach 40%, and the EAA / NEAA values ​​are all above 60%, indicating that the essential amino acid composition is reasonable and the ratio is balanced, but the EAA / NEAA value of the meat sample in the ultrasonic treatment group is significantly lower than that in the control group, indicating that ultrasonic-assisted thawing will cause protein loss, thereby destroying the essential amino acid composition and ratio balance; compared with meat frozen and thawed three times, the essential amino acid composition and ratio of the meat samples of the UT320 and UT180 groups frozen and thawed seven times remained basically stable. Compared with the control group, the meat samples of the UT180 group have better essential amino acid quality, indicating that 180W ultrasonic-assisted thawing treatment is conducive to the reasonable composition and balanced ratio of essential amino acids in meat. Therefore, common thawing methods and ultrasonic thawing after multiple freezing and thawing will cause meat protein loss, but ultrasonic assisted thawing is beneficial to the maintenance of meat amino acid quality, especially meat frozen and thawed by 320W ultrasound, which has the best effect. However, ultrasound will also destroy the composition and proportion balance of essential amino acids, while 180W ultrasonic assisted thawing can slow down this process and maintain a reasonable composition and balanced proportion of essential amino acids in meat.

[0282] 3.10 Changes in mutton quality during freeze-thaw period after fruit thinning polyphenol treatment

[0283] Depend on Fig.25It can be seen that the hardness of the mutton in the four groups decreased with the increase of freezing and thawing times. During the freezing and thawing period, the hardness of the mutton in the four groups was in the order of the sparse fruit polyphenol group, epicatechin group, TBHQ group and blank group. Among them, after freezing and thawing once, the hardness value of the mutton in the sparse fruit polyphenol group was significantly higher than that in the epicatechin group, TBHQ group and blank group by 29.57%, 26.72% and 36.90% (P < 0.05). After freezing and thawing for 3 times, the hardness of the mutton in the sparse fruit polyphenol group and epicatechin group was similar, and the hardness of the sparse fruit polyphenol group was significantly increased by 27.01% compared with the blank group (P < 0.05). At the end of freeze-thaw, the hardness of the sparse fruit polyphenol group, epicatechin group, TBHQ group and blank group decreased by 24.48%, 23.59%, 30.37% and 37.28% respectively compared with the initial value; with the increase of freeze-thaw times, the elasticity of the mutton in the four groups showed a trend of first decreasing and then stabilizing, while there was no significant difference among the groups at the third and fifth freeze-thaw times (P>0.05). At the end of freeze-thaw, the elasticity of the sparse fruit polyphenol group, epicatechin group, TBHQ group and blank group decreased by 35.33%, 36.59%, 39.67% and 40.22% respectively compared with the initial value. In summary, phenol treatment is conducive to the stable maintenance of mutton physical properties, which can slow down the excessive reduction of hardness of frozen-thawed mutton and maintain the taste of meat.

[0284] Multiple freeze-thaw cycles can also lead to fat oxidation. The present invention analyzes the fat oxidation of mutton (2-thiobarbituric acid method). The TBARS value of mutton during freeze-thaw cycles is shown in Figure 2. Fig.26 As shown in the results, the TBARS values ​​of the four groups of mutton first decreased and then increased with the increase of freezing and thawing times. During the freezing and thawing period of mutton, there was no significant difference in the TBARS values ​​of the four groups of mutton after freezing and thawing once (P>0.05), and the TBARS value of the sparse fruit polyphenol group was the lowest at 0.13 mg / kg; after freezing and thawing for three times, the TBARS value of the sparse fruit polyphenol group was significantly lower than that of the TBHQ group and the blank group by 14.90% and 27.76% (P<0.05); after freezing and thawing for five times, the TBARS value of the sparse fruit polyphenol group was significantly lower than that of the other three groups (P<0.05), and was 11.92%, 16.12% and 28.21% lower than that of the epicatechin group, TBHQ group and the blank group, respectively (P<0.05). In conclusion, under different treatment conditions, adding sparse fruit polyphenol to mutton can greatly inhibit fat oxidation in mutton during freezing and thawing.

[0285] 4. Screening of various Chinese processing technologies for mutton

[0286] The hind legs of six intact male goats aged 24 months were selected, and the main identified muscles were the biceps femoris, semitendinosus and semimembranosus. The meat samples were transported to the laboratory with ice packs and stored at -20°C. During processing, all samples were thawed at 4°C for 24 hours to remove surface fat and connective tissue. Then, the meat samples were cut into cubes with dimensions of 3cm×1.5cm×1cm (i.e., length×width×height) and randomly divided into 9 groups. Two groups were randomly divided into a blank control (meat without any additives) and a marinade control (meat marinated for 60 minutes with 50mL of a liquid additive containing 2% salt, 1.25% pepper, 1.5% fennel, 0.5% dill, 1% chopped green onion, 1% cinnamon powder and 1% cooking wine; weight percentage). The remaining seven groups first used the same pickling method as the pickled control group, and then used seven heat treatment methods (steaming, boiling, stewing, roasting, frying, pan-frying and drying). The nutritional and safety indicators of mutton under commonly used Chinese processing methods were systematically evaluated, and the impact on their quality was analyzed.

[0287] The study showed that different heat processing methods had a significant effect on the nutritional content of mutton. The results of the moisture content of mutton legs showed that the moisture content of the pickled samples (77.5%) was 6.6% higher than that of the blank control group (70.9%) due to the addition of pickling liquid. The moisture content of the samples that underwent different heat processing was significantly reduced, ranging from 33.5% in dried meat to 55.2% in steamed meat. Since steamed meat and boiled meat are processed by wet methods, their moisture content is relatively high, while the moisture content of samples processed by dry air (such as drying) is lower (P<0.05).

[0288] Different heat treatment methods can lead to significant changes in protein content, and heat treatment increases protein content. The highest protein content is in jerky (49.7%), followed by roasting, steaming, boiling, braising, deep-frying and pan-frying. Among them, the protein content of fried samples is the lowest, at 31.2%. The change in protein content is affected by heat treatment conditions (such as temperature, time, etc.). The greater the water loss of the meat, the higher the relative protein content. During the frying process, the protein content is low due to the rapid denaturation of the protein due to high temperature heating.

[0289] The total fat content of the blank control and pickled control samples was 8.7% and 11.0%, respectively. Except for the steaming and boiling groups, which showed no significant changes in fat content, other thermal processing treatments significantly increased the fat content (P<0.05). In particular, the fat content of the fried and deep-fried samples increased significantly (P<0.05), which was related to the addition of rapeseed oil during the frying process. Considering health needs, low-fat steaming and boiling processing methods are more recommended, while deep-frying methods should not be used too much.

[0290] Different thermal processing methods significantly affect the edible quality of mutton. Compared with the control group, the brightness L* value of mutton samples treated with steaming, boiling, stewing and frying increased significantly (P<0.05), among which the L* value of boiled meat was the highest. The L* value of mutton samples treated with frying, baking and drying decreased, among which the fried sample had the lowest L* value. The red a* value of all treated samples decreased (P<0.05), among which the a* value of steaming, boiling and stewing was the lowest. Frying and deep-frying treatments significantly increased the yellow b* value (P<0.05), showing a higher yellowness.

[0291] The results of hardness, chewiness, elasticity and cohesiveness of heat-treated samples showed that the texture properties of heat-treated samples were significantly higher than those of the control group (P<0.05), which was mainly due to the enhancement of muscle structure caused by protein denaturation and water loss. The dry samples with the lowest water content had the highest hardness, chewiness and elasticity values, while the stewed, fried and deep-fried samples were relatively low in texture properties. This indicates that water loss and processing conditions have a significant impact on meat structure.

[0292] Thermal processing produces potentially harmful ingredients such as nitrite and polycyclic aromatic hydrocarbons (PAHs). The nitrite content in the blank control was 3.95 mg / kg, while it reached 32.68 mg / kg in the pickled control, exceeding the maximum residue limit of 30.00 mg / kg specified in GB2760-2014. The nitrite content of steamed, stewed, boiled, and dried meat is lower than that of fried, deep-fried, and baked meat. PAHs are mainly produced in high temperature or smoked environments, and higher levels were detected in fried, deep-fried, and baked samples (as shown in Table 3). It is recommended to choose wet processing to reduce harmful substances.

[0293] In the development of stewed mutton products, Hengshan mutton from a certain region was used as raw material, and the processing technology was determined through formula optimization and process exploration. After the mutton was cut into pieces, it was boiled with water to remove the floating foam, and seasonings were added and stewed on low heat for 60 minutes. The finished products were vacuum-packed and divided into a control group, a pasteurization group, a boiling water bath sterilization group, and a high-temperature sterilization group. The results showed that the high-temperature sterilization group had the highest content of flavor substances (see Fig. 27 and Fig.28 ). When stewed mutton was stored at 4, 25, and 37°C, the predicted shelf life was 140, 86, and 67 days, respectively.

[0294] Six nutritious and healthy steamed meat products have been developed, each using a different Chinese herbal medicine formula to provide blood-tonifying, lipid-lowering, spleen-strengthening and other effects. In the mutton preservation technology demonstration, the effects of refrigeration, ice temperature and freezing on mutton quality were studied, and the best thawing method was selected by combining air thawing, static water thawing and ultrasonic thawing. Combined with cascade processing technology, Yulin mutton by-products have been developed into sauce-marinated, grilled, air-dried and other products, forming a variety of mutton products and improving the efficient use of mutton.

[0295] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for improving the quality of mutton and for cascade processing and storage, characterized in that: The following steps are involved: Step 1. Refrigerated, iced, or frozen storage methods: (a) Classify fresh mutton according to different parts and expected storage time; (b) For mutton that needs to be stored for a short period of time, it should be refrigerated at 0°C to 4°C or stored in ice at -1°C to 0°C to maintain the tenderness and best taste of the meat; (c) For mutton that needs to be stored for a long time, it is stored in a frozen state below -18°C to ensure that the meat is not damaged during the freezing process and to preserve its nutritional value and flavor to the greatest extent; Step 2. Modified atmosphere fresh-keeping packaging method: (a) Before storage and transportation, the mutton is packaged in a controlled atmosphere fresh-keeping package; (b) The gas composition in the package is controlled at a ratio of 1-5% low oxygen, 20-30% high carbon dioxide, and 65-79% nitrogen to slow down the oxidation process of the mutton and inhibit the growth of microorganisms; (c) The modified atmosphere packaging material should be a composite film with high barrier properties and good mechanical properties to ensure the sealing and durability of the packaging; Step 3. Application of natural biological preservation technology: (a) spraying or soaking the surface of mutton with a natural biological fresh-keeping liquid, wherein the fresh-keeping liquid is composed of plant extracts, fermentation products or natural antioxidants; Preparation of preservative: using kiwi polyphenol, apple polyphenol, tea polyphenol natural biological preservatives to mix and prepare the preservative solution; Mutton soaking: Soak the mutton in the preservative solution for 30 minutes to 1 hour to ensure that the preservative evenly penetrates into the meat; Step 4. Full chain storage management: (a) Establish a full-chain storage management system from slaughtering, primary processing, packaging, storage, transportation to terminal sales; (b) Real-time monitoring and recording of key storage parameters such as temperature, humidity and gas composition are performed at each stage to ensure the stability of the storage environment.

2. A method for improving the quality of mutton and for cascade processing and storage as claimed in claim 1, characterized in that: The refrigerated, ice temperature, and frozen storage methods: (1) Refrigerated storage Temperature control: Store fresh lamb in a refrigerated environment at 0°C to 4°C; Humidity control: Maintain the relative humidity of the storage environment at 85% to 90%; Storage time: At this temperature, the lamb can be stored for 7 to 10 days, during which time the color, smell and texture of the lamb should be checked regularly. (2) Ice temperature storage Temperature control: Store the lamb at -1°C to 1°C, using the ice temperature environment to inhibit the growth of microorganisms and delay enzymatic reactions; Humidity control: Keep the ambient humidity between 90% and 95%; Storage time: Under ice temperature conditions, the storage period of mutton can be extended to 15 days, and its flavor and nutrients are well preserved; (3) Frozen storage Rapid freezing: The lamb is quickly frozen to below -18°C to minimize the damage to the cell structure by ice crystals; Thawing method: Use ultrasonic thawing method to reduce the loss of juice during the thawing process and maintain the texture and nutrients of the mutton; the thawing temperature is controlled at 4°C, and slow thawing method is used to ensure uniform thawing.

3. A method for improving the quality of mutton and for cascade processing and storage as claimed in claim 1, characterized in that: The modified atmosphere fresh-keeping packaging method: Packaging material selection: choose multi-layer composite film materials with good barrier properties; Gas composition control: according to the storage time and environmental conditions of mutton, the gas ratio in the package is adjusted; the typical gas conditioning formula is 70% nitrogen + 30% carbon dioxide, or an appropriate amount of oxygen is added to maintain the bright red color of mutton; Packaging and sealing: Using vacuum packaging technology, the mutton is placed in a modified atmosphere package, vacuumed and filled with preset gas, and then heat-sealed to ensure the airtightness of the package.

4. A method for improving the quality of mutton and for cascade processing and storage as claimed in claim 1, characterized in that: The natural biological preservation technology is applied to: Preparation of preservative: using kiwi polyphenol, apple polyphenol, tea polyphenol natural biological preservatives, mixing in a certain proportion to prepare a preservative solution; Mutton soaking: Soak the mutton in the preservative solution for 30 minutes to 1 hour to ensure that the preservative evenly penetrates into the meat; Air drying: After soaking, air dry the mutton at a temperature between 4°C and 8°C for 30 minutes to 1 hour.

5. A method for improving the quality of mutton and for cascade processing and storage as claimed in claim 1, characterized in that: The whole chain storage management: Temperature and humidity monitoring: During the entire storage process, intelligent temperature and humidity monitoring equipment is used to monitor environmental parameters in real time, and the temperature and humidity are automatically adjusted through the data feedback system to ensure stable storage conditions; Regular quality testing: every three days, the quality of the stored mutton is tested for microbiological indicators, moisture content, color and smell to ensure that the quality of the mutton meets the requirements; Storage time adjustment.

6. A method for improving the quality of mutton and for cascade processing and storage as claimed in claim 5, characterized in that: The storage time adjustment is as follows: according to the storage conditions and quality test results of the mutton, the storage time and method are adjusted to extend the ice temperature storage period or perform frozen storage in advance.

7. A method for improving the quality of mutton and for cascade processing and storage as claimed in claim 1, characterized in that: The following steps are also included: 1) Intelligent storage module: (a) Based on intelligent sensing technology, real-time monitoring of the temperature, humidity and gas composition of the mutton storage environment; 2) Intelligent packaging module: (a) Using intelligent modified atmosphere packaging equipment, the gas ratio in the package is automatically adjusted according to the type, part and storage requirements of the mutton, so as to achieve precise modified atmosphere fresh-keeping packaging; (b) The system monitors the gas composition in the package in real time through sensors, and automatically issues an alarm or adjusts gas injection when it detects changes in gas composition or failure of the package seal to ensure the effectiveness and sealing of the package.

8. A method for improving the quality of mutton and for cascade processing and storage as claimed in claim 7, characterized in that: The following steps are involved: 1) Intelligent fresh-keeping module: (a) Through the intelligent spraying system, the appropriate amount of natural biological preservative liquid is automatically selected and applied according to the number and type of bacterial colonies on the surface of the mutton to ensure the accuracy and effectiveness of the preservation treatment; (b) The preservation module interacts with the storage and packaging modules to collaboratively optimize the overall preservation and storage strategy of mutton; 2) Intelligent full-chain management module: (a) Using the Internet of Things (IoT) technology, establish an intelligent management system for the entire chain from slaughtering, primary processing, packaging, storage, transportation to terminal sales, and conduct real-time monitoring and data collection for each link; (b) The system automatically identifies key control points in the storage chain through big data analysis, conducts risk assessment and timely warning, realizes dynamic adjustment and optimization management, and ensures that the quality of mutton is always maintained in the best condition; (c) Through the intelligent management platform, storage and management data of each link are uploaded to the cloud for unified management and analysis, and quality traceability reports are generated to ensure the transparency and efficiency of the entire storage process.

9. An intelligent mutton storage management system for implementing a mutton quality improvement and tiered processing and storage method as described in any one of claims 1-2, characterized in that: The intelligent mutton storage management system comprises: Storage unit: used to control the temperature and humidity conditions according to the storage requirements of mutton. The storage unit is equipped with a temperature sensor and a humidity sensor to monitor and automatically adjust the storage environment in real time to ensure the quality of mutton under different storage methods; Modified atmosphere packaging unit: used for modified atmosphere fresh-keeping packaging of mutton. The modified atmosphere packaging unit is equipped with a gas composition control system that can accurately adjust the ratio of oxygen, carbon dioxide and nitrogen in the package, and uses a high-barrier composite film for packaging to delay the oxidation process and inhibit the growth of microorganisms; Fresh-keeping treatment unit: including a natural biological fresh-keeping liquid spraying or soaking device, which automatically adjusts the concentration and application amount of the fresh-keeping liquid according to the microbial load on the surface of the mutton to achieve the best fresh-keeping effect; Full-chain management unit: used to monitor and record the entire process from slaughtering, primary processing, packaging, storage to terminal sales, including real-time data collection and analysis of key storage parameters such as temperature, humidity, and gas composition, to ensure the quality and freshness of mutton throughout the supply chain.

10. The intelligent mutton storage management system according to claim 9, characterized in that: The intelligent mutton storage management system comprises: Refrigerated storage module: equipped with intelligent temperature and humidity controller, used to store mutton in an environment of 0℃ to 4℃ and maintain a relative humidity of 85% to 90%. The system automatically monitors and adjusts the storage environment to ensure that the mutton maintains the best quality during the refrigerated period of 7 to 10 days; Ice storage module: used to store mutton in an ice temperature environment of -1°C to 1°C. The ice storage module is equipped with a high-precision temperature and humidity control system, which can maintain the ambient humidity between 90% and 95%, extending the storage period of mutton to 15 days while maintaining its flavor and nutrients; Frozen storage module: equipped with rapid freezing equipment, which can reduce the temperature of mutton to below -18℃ in a short time to minimize the damage of ice crystals to the cell structure; the module is also equipped with an ultrasonic thawing system, which can evenly thaw the mutton at 4℃, reduce juice loss and maintain texture and nutrients; Intelligent monitoring module: used for real-time monitoring, recording and optimizing all storage conditions of the refrigerated storage module, the ice temperature storage module and the frozen storage module, and realizing intelligent decision-making of storage management through data analysis to ensure that the high quality of mutton is maintained throughout the storage process.

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