Crayfish and perilla frutescens flavored product and preparation process thereof

Abstract

The invention discloses a crayfish and purple perilla flavored product and a preparation process thereof, and relates to the technical field of food processing. The preparation process comprises the following steps: screening and pretreating a crayfish raw material, preparing a perilla frutescens flavor stock solution, preparing composite spices, preparing a composite seasoning liquid, performing low-temperature vacuum rolling and kneading to be tasty, performing precise temperature control deep-frying and cooking, performing ultralow-temperature quick-freezing and fresh-keeping, and performing packaging and preservation. By adopting the technical scheme, the technical problems that in an existing crayfish processing technology, the meat quality and taste are poor, flavor substances are prone to volatilization and loss, and crayfish shells are difficult to peel are solved, and the beneficial effects that the product is full and elastic in meat quality and easy to peel, the purple perilla flavor is rich and lasting, and the quality is stable can be achieved.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a crayfish product with perilla flavor and its preparation process. Background Technology

[0002] Crayfish, a popular aquatic product, has seen its consumption expand globally, especially in China, becoming a national delicacy. With the accelerating pace of modern life and increasing consumer demand for ready-to-eat and convenient foods, the processed food market, represented by frozen seasoned crayfish products, is booming. These products, due to their ease of storage and convenient consumption, demonstrate enormous market potential and economic value in e-commerce, supermarkets, household consumption, and catering channels. Against this backdrop, improving the unique flavor, quality stability, and processing efficiency of processed crayfish products to meet increasingly diversified and high-standard market demands has become a focus of attention within the industry.

[0003] Currently, existing crayfish processing technologies mainly include key stages such as raw material pretreatment, cooking, flavor blending, and freezing. During cooking, traditional methods such as boiling, steaming, or frying are typically used to ensure food safety and achieve initial solidification of the crayfish meat. Subsequently, various spices and sauces are added to blend the flavors, giving the product specific taste characteristics. Among these, perilla, a seasoning rich in unique aromatic compounds, has been experimentally applied in some crayfish products due to its refreshing and slightly spicy aroma, and has gained some consumer favor. Traditional quick-freezing processes, such as forced-air freezing or contact freezing, are widely used to extend the shelf life of products, enabling crayfish products to be sold across regions and seasons. These existing technologies have effectively promoted the large-scale development of the crayfish processing industry in the past, addressing the initial market demand for convenient ready-to-eat products, transforming crayfish from a seasonal ingredient into a year-round consumer product.

[0004] However, as consumers' demands for food quality continue to rise, and their pursuit of more refined and personalized flavor experiences grows, some inherent characteristics of the aforementioned existing technologies at the principle level are gradually revealing their deep limitations in addressing new challenges. Specifically, traditional crayfish processing, especially for frozen seasoned products, presents significant inherent contradictions in the synergistic optimization of flavor preservation, meat texture, and production efficiency. The reason for this lies in the fact that crayfish meat is delicate, and its muscle fiber structure is relatively fragile. During high-temperature cooking and subsequent freezing / thawing cycles, protein denaturation and moisture loss easily occur. Traditional high-temperature cooking, while achieving cooking, often leads to excessive contraction and decreased elasticity of the crayfish meat tissue. After thawing, the meat is dry, lacks plumpness, and tends to stick tightly to the shell, severely affecting the convenience for consumers to peel and eat. More importantly, for specialty seasonings like perilla, which are rich in volatile aromatic compounds, their unique flavor substances are highly susceptible to volatilization, oxidation, or decomposition under prolonged or high-temperature cooking conditions. This leads to a significant weakening or even complete loss of the perilla aroma, resulting in a single-flavor final product that fails to fully showcase the distinctive characteristics of perilla and its harmonious integration with shrimp meat. Even when added later in the cooking process, it is difficult to achieve deep penetration and stable preservation of the flavor in the shrimp meat, and it is prone to further degradation during subsequent storage. In addition, traditional quick-freezing techniques often result in large ice crystals. These ice crystals cause irreversible physical damage to the cell walls of shrimp meat during their growth, further exacerbating the loss of juices after thawing. This not only affects the springy texture of the shrimp meat but also causes water-soluble flavor substances to be lost along with the juices, further weakening the product's flavor.

[0005] While existing processes prioritize production efficiency and the formation of basic flavors, they struggle to effectively address key challenges in crayfish processing, such as tough and dry meat after thawing, unstable and easily lost flavor, and difficulty in peeling the shells. This inherent contradiction—the challenge of precisely managing the stable and efficient injection and retention of volatile flavor compounds while simultaneously optimizing the tenderness and ease of peeling of the meat—constitutes a deep-seated, albeit not readily apparent, technical hurdle in the current crayfish processing industry. Summary of the Invention

[0006] The purpose of this invention is to provide a crayfish product with perilla flavor and its preparation process, so as to solve the problems of poor meat texture, easy volatilization and loss of flavor substances, and difficulty in peeling the shell that are common in existing crayfish processing technologies.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A crayfish product with perilla flavor and its preparation process, comprising: The crayfish and perilla-flavored product of this invention comprises the following main ingredients: 100 parts crayfish, 0.5-1.5 parts perilla flavoring concentrate, 5-10 parts compound spices, 10-15 parts edible vegetable oil, 1.5-2.5 parts salt, 1-2 parts white sugar, 2-3 parts compound flavor enhancer, 8-12 parts brewed soy sauce, 4-6 parts cooking wine, 1-1.5 parts ginger, 5-8 parts garlic, 0.5-1.0 parts Sichuan peppercorns, 0.8-1.5 parts cumin, 1-2 parts chili peppers, and 15-25 parts pork bone broth.

[0008] The preparation process of the crayfish perilla-flavored product of the present invention is characterized by including the following steps: Step S1: Screening and pretreatment of crayfish raw materials; S1-1, Raw Material Selection: Select healthy, vigorous, disease-free, and undamaged fresh crayfish. The size of the crayfish is uniformly controlled at 4-8 qian / piece (i.e., the weight of a single piece is 15-30 grams). During the selection process, manual visual inspection combined with weighing and sorting equipment is used to grade the crayfish to ensure that the size of the crayfish is uniform. This is beneficial to the consistency of heating and flavoring during subsequent processing.

[0009] S1-2, Multi-stage Cleaning: The screened crayfish are placed in a cleaning tank equipped with circulating water and an ozone generator. First, a preliminary rinse is performed with room-temperature running water to remove surface mud and debris. Then, the crayfish undergo a second-stage cleaning process, soaking in ozone water with a concentration of 0.5-1.0 ppm for 5-10 minutes at a temperature controlled between 5-10℃. The strong oxidizing properties of ozone help kill pathogenic microorganisms on the crayfish's surface and effectively degrade some organic pollutants, while the low temperature helps maintain the crayfish's vitality. Finally, the crayfish are rinsed at least twice with purified water to thoroughly remove any ozone residue and impurities, ensuring the cleanliness of the raw material.

[0010] S1-3, Expelling Sand / Deveining: After cleaning, the crayfish are placed in a clean, quiet rearing tank filled with pre-treated purified water and a small amount of salt (e.g., 0.1%-0.2% of the water mass) to simulate a natural physiological environment, prompting the crayfish to expel mud and feces from their digestive tracts. The rearing time is controlled at 12-24 hours, with the water changed every 6-8 hours to ensure thorough expulsion of sand. After the rearing period, the intestinal tract of the crayfish is completely removed using professional deveining equipment and physical methods (e.g., using a stainless steel shrimp vein remover or a vacuum suction device). This deveining process aims to improve the convenience and safety of the product for consumption.

[0011] S1-4, Sterilization Treatment: After degumming, the crayfish are quickly drained of surface moisture and then sterilized. The sterilization treatment uses ultraviolet C (UV-C) irradiation or hypochlorous acid immersion. If UV-C irradiation is used, the crayfish are evenly spread on a conveyor belt and passed through a sealed cavity equipped with a 254nm ultraviolet lamp, with the irradiation intensity controlled at [insert value here]. Irradiation time is 1-2 minutes. If hypochlorous acid is used for soaking, the crayfish are immersed in a hypochlorous acid solution with an effective chlorine content of 50-100 ppm for 1-2 minutes, and then immediately rinsed with purified water. This sterilization step aims to further reduce the microbial load on the surface of the crayfish, providing a safer raw material for subsequent processing.

[0012] Step S2: Preparation of perilla flavor concentrate; S2-1, Selection of Perilla Leaves: High-quality perilla leaves from Hunan Province are selected. The perilla leaves are preferably harvested from late spring to early summer, between the time the dew dries and noon each day, as the aromatic substances are most abundant and the quality is best during this period. The perilla leaves should be bright green, free from pests and diseases, and free from mud and impurities.

[0013] S2-2, Steam Distillation Extraction: Selected perilla leaves are initially washed and drained, then chopped to an appropriate size to increase the contact area with steam. The processed perilla leaves are placed in a stainless steel steam still. Saturated steam is introduced, with the steam pressure controlled at 0.1-0.2 MPa and the temperature maintained at 100-105℃. The distillation process lasts 3-4 hours. The steam passes through the perilla leaves, carrying away the volatile aromatic substances, forming a steam-water mixture.

[0014] S2-3, Condensation and Separation: The water vapor mixture is cooled by a condenser, and the condensate enters an oil-water separator. Since perilla essential oil and water are immiscible and have different densities, gravity stratification separates the perilla essential oil from the perilla hydrosol. The perilla essential oil is the upper oily layer, whose main components are perillaldehyde, limonene, eugenol, etc. The perilla hydrosol is the lower aqueous solution, containing a small amount of water-soluble aromatic substances.

[0015] S2-4, Standardization of Essential Oils and Hydrosols: The extracted perilla essential oil and perilla hydrosol were subjected to quality testing and standardization. The key indicator for perilla essential oil is the perillaldehyde content, which this invention requires to be no less than 60% (detected by gas chromatography-mass spectrometry). The perilla hydrosol was tested for its pH value, total solids content, and characteristic aromatic component content. The perilla essential oil and perilla hydrosol were stored separately in a light-proof, low-temperature (4-8℃) environment, sealed for later use. The perilla flavor concentrate can be used alone with perilla essential oil, or a blend of perilla essential oil and perilla hydrosol in a specific ratio to achieve a richer flavor profile.

[0016] Step S3: Preparation of compound spices and formulation of compound seasoning liquid; S3-1, Pretreatment of core spices: Xinjiang cumin: Select plump, brownish-yellow Xinjiang cumin seeds. Lightly roast them at 120-130℃ for 5-8 minutes to release their unique aroma. After roasting and cooling, grind them into a fine powder of 200 mesh or finer using an ultra-micro grinder to ensure the full release and uniform distribution of their flavor compounds.

[0017] Jinyang Green Sichuan Pepper: Select Jinyang green Sichuan peppercorns with a bright green color and a strong numbing flavor. Lightly roast them at 100-110℃ for 3-5 minutes to remove the raw, astringent taste and enhance the numbing effect. After roasting and cooling, grind them into a fine powder of less than 100 mesh using a grinding machine. Further sieving using a grading sieve can be used to ensure uniform fineness.

[0018] S3-2, Preparation of auxiliary seasonings: Shandong Jinxiang garlic: Select fresh Shandong Jinxiang garlic, peel and clean it. Use a high-speed chopper to make it into garlic paste or minced garlic, with the garlic paste particle size controlled at 3-5 mm to provide a unique garlic aroma and taste.

[0019] Guizhou Zunyi Lantern Pepper: Selected Guizhou Zunyi lantern peppers with bright color and moderate spiciness. The peppers are stemmed and seeded, then dried until the moisture content is below 10%, and finally ground into a 20-40 mesh coarse powder to provide a mild spiciness and color.

[0020] S3-3, Compound Flavor-Enhancing Seasoning: This invention employs a compound flavor-enhancing seasoning, the main components of which are yeast extract, hydrolyzed vegetable protein (such as hydrolyzed soy protein), edible salt, maltodextrin, and disodium inosinate (such as disodium 5'-inosinate and disodium 5'-guanylate). The compound flavor-enhancing seasoning is formulated by weight percentage as follows: yeast extract 35%, hydrolyzed vegetable protein 25%, edible salt 20%, maltodextrin 18%, and disodium inosinate 2%. This seasoning aims to provide rich umami, balance the overall flavor, and enhance the aftertaste of the product.

[0021] S3-4, Preparation of pork bone broth: Select fresh pork bones (such as leg bones and spine bones), blanch them to remove blood and impurities, and then place them in a pressure cooker along with ginger slices and scallion segments, adding sufficient purified water. Cook at a pressure of 0.15-0.2 MPa and a temperature of 115-120℃ for 6-8 hours. After cooking, filter out bone residue and spices, defatt the broth, and then concentrate it using a vacuum concentration device until the Brix value reaches 5-8%. This pork bone broth provides a natural umami base and a rich, mellow flavor to the finished product.

[0022] S3-5, Precise Preparation of Compound Seasoning Liquid: In a clean mixing tank, mix the components according to the following proportions (based on the total mass of the compound seasoning liquid): Perilla essential oil (or a blend of perilla essential oil and perilla hydrosol): 0.5%-1.5%; Cumin powder: 0.8%-1.5%; Sichuan pepper powder: 0.5%-1.0%; Minced garlic: 5%-8%; Coarse bell pepper powder: 1%-2%; Compound flavor enhancer: 2%-3%; Concentrated pork bone broth: 15%-25%; Brewed soy sauce: 8%-12%; Cooking wine: 4%-6%; Salt: 1.5%-2.5%; White sugar: 1%-2%; Ginger (sliced ​​or grated): 1%-1.5%; Edible vegetable oil (such as high-oleic sunflower oil): 10%-15%; Purified water: balance.

[0023] After all components are added, the mixture is thoroughly stirred using a high-shear mixer to ensure that all solid powders are evenly dispersed and liquid components are fully emulsified and blended to form a stable and homogeneous compound seasoning liquid. Once prepared, the compound seasoning liquid should be immediately cooled to 0-4°C and stored in a sealed container to prevent the volatilization of flavor substances.

[0024] Step S4: Low-temperature vacuum tumbling to infuse flavor; S4-1, Equipment Preparation: Select a horizontal vacuum tumbler with refrigeration and a vacuum pump. Thoroughly clean and disinfect the equipment before putting it into use, and pre-cool it to 0-4℃.

[0025] S4-2, Seasoning Process: Combine the pre-treated crayfish (drained) from step S1 with the prepared low-temperature compound seasoning liquid from step S3, at a crayfish to seasoning liquid mass ratio of 3:1 to 5:1, and place them into a vacuum tumbler. Start the vacuum pump to evacuate the tumbler tank to an absolute pressure of 0.08-0.095 MPa. Under vacuum, start the tumbling program, controlling the tumbling speed at 5-10 rpm and maintaining the tumbling temperature at 0-4℃. The total tumbling time should be controlled at 2-4 hours. Pause the tumbling process for 5-10 minutes every 30 minutes to prevent excessive stress and damage to the crayfish meat.

[0026] S4-3, Mechanism of Action: The low-temperature vacuum tumbling and flavoring process utilizes a vacuum environment to expel air from the crayfish meat tissue. After the vacuum is released, the compound seasoning liquid can penetrate the crayfish meat fibers more quickly and deeply, achieving deep flavor infusion. Simultaneously, the low-temperature environment effectively inhibits microbial growth, maximizing the retention of volatile aromatic substances from perilla and other spices, preventing their oxidation or volatilization at room temperature. The mechanical action of tumbling, while ensuring flavor infusion, also moderately denatures the crayfish meat proteins, helping to improve the water retention and tenderness of the crayfish meat, and reducing adhesion between the meat and shell during subsequent cooking.

[0027] Step S5: Precisely control the temperature during deep-frying until cooked; S5-1, Frying Equipment and Oil: A continuous automatic fryer with high-precision temperature control and an automatic circulating filtration system is used. Edible vegetable oils with high smoke points and good oxidative stability are selected, such as high-oleic sunflower oil, refined palm oil, or corn germ oil, to ensure stable oil quality during frying. The oil level in the fryer's oil tank should be maintained at the set level, and new oil should be added regularly.

[0028] S5-2, Frying Process Parameters: After draining excess compound seasoning liquid from the crayfish marinated in step S4, evenly fry them in preheated edible vegetable oil at 160-170℃. The frying time is precisely controlled between 60-90 seconds. The frying process is controlled by an automated conveyor belt to ensure that each crayfish is heated evenly. During the frying process, the real-time temperature sensor and PID (proportional-integral-derivative) controller of the fryer work together to precisely adjust the power output of the heating element, controlling the oil temperature fluctuation range within ±2℃.

[0029] S5-3, Mechanism of Action: The precise temperature-controlled frying process employs a "flash frying" principle, which rapidly solidifies the surface of the crayfish at high temperatures within a short time, forming a protective shell that effectively locks in the moisture and flavor compounds inside the crayfish meat, minimizing juice loss and toughness caused by protein denaturation. This short-term high-temperature treatment also quickly kills residual microorganisms, ensuring food safety. Simultaneously, the crayfish meat shrinks during frying, creating tiny gaps between it and the shell, laying the foundation for easy peeling later. Precise temperature control and timing are key to ensuring the crayfish meat is cooked through yet tender, and has a golden-brown, appealing exterior.

[0030] Step S6: Ultra-low temperature quick-freezing for preservation; S6-1, Cooling and Draining: After frying, the crayfish are quickly transported to the cooling zone via conveyor belt, where they are rapidly cooled to room temperature using powerful fans or cooling channels, and excess oil adhering to the surface is thoroughly drained. This rapid cooling helps to stop the internal cooking of the crayfish meat and reduces the amount of heat transferred into the quick-freezing equipment.

[0031] S6-2, Ultra-low Temperature Quick Freezing: The cooled crayfish are evenly spread on a conveyor belt and fed into a liquid nitrogen tunnel quick-freezing machine. The ambient temperature inside the liquid nitrogen tunnel quick-freezing machine is set between -120℃ and -180℃. Through direct spraying of liquid nitrogen or a circulating cold air system, the core temperature of the crayfish is rapidly reduced from room temperature to below -18℃ in a very short time (e.g., within 5-10 minutes).

[0032] S6-3, Mechanism of Action: The ultra-low temperature quick-freezing technology utilizes the extremely low temperature and ultra-fast cooling rate of liquid nitrogen to cause water in the crayfish tissue to crystallize rapidly inside and outside the cells, forming tiny and uniformly distributed ice crystals. These tiny ice crystals cause minimal physical damage to the cell walls of the crayfish meat, effectively avoiding the formation of large ice crystals caused by traditional slow freezing. This minimizes juice loss (drip rate) during thawing, maintaining the cell integrity and natural tissue structure of the crayfish meat. This is crucial for maintaining the springy texture, plumpness, and stable retention of water-soluble flavor substances in the thawed crayfish meat.

[0033] Step S7: Packaging and Storage; S7-1, Vacuum Packaging: Quick-frozen crayfish are rapidly repackaged. The repackaging process, based on product specifications and market demand, involves placing a certain quantity of crayfish and a small amount of accompanying seasoning sauce (which solidifies during frying and freezing) into pre-prepared food-grade composite barrier film bags. These composite barrier film bags are typically composed of multiple layers of polyester (PET), nylon (PA), and polyethylene (PE), possessing excellent oxygen barrier properties. ) and water vapor barrier properties ( Then, a vacuum packaging machine is used to create a vacuum level of over 95%, followed by heat sealing. This vacuum packaging effectively isolates oxygen and water vapor, inhibits the growth of microorganisms and fat oxidation, and prevents freezing and burning.

[0034] S7-2, Cold Chain Transportation and Storage: Vacuum-packed products are immediately placed in a cold storage facility at -18°C or below. Throughout the transportation and sales process, cold chain management regulations are strictly followed to ensure that the products are always kept frozen at -18°C or below. This cold chain management aims to maintain optimal product quality and extend shelf life.

[0035] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention utilizes a low-temperature vacuum tumbling and flavoring process to effectively protect the muscle fiber structure of shrimp meat and improve its water retention. Precise temperature control during frying ensures that the shrimp meat cooks quickly without losing water, creating tiny gaps between the shrimp meat and the shell. Ultra-low temperature quick-freezing minimizes damage to cells caused by ice crystals. These synergistic effects result in a product with intact shrimp muscle fiber structure, a full and elastic texture, and easy separation of shrimp meat from the shell after thawing and reheating, greatly improving the convenience of peeling and eating for consumers and enhancing their dining experience.

[0036] This invention uses steam distillation to prepare high-purity, high-content perilla flavor concentrate, avoiding the destruction of volatile flavor substances caused by traditional high-temperature cooking; low-temperature vacuum tumbling process ensures that perilla flavor substances deeply penetrate and stably lock in the shrimp meat; this deep integration and stable preservation of flavor makes the perilla aroma bright, unique and long-lasting after thawing, perfectly blending with the freshness of crayfish, with rich flavor layers, overcoming the problem of traditional products having a single flavor and being easy to lose.

[0037] The invention's strict raw material pretreatment and sterilization processes effectively control microbial contamination; ultra-low temperature quick-freezing technology maximizes the preservation of product freshness and reduces juice loss and flavor substance loss during thawing; vacuum packaging effectively isolates the product from the influence of the external environment and inhibits oxidation reactions; these comprehensive measures synergistically extend the product's shelf life, ensuring that the product maintains a high level of color, aroma, taste, and nutritional components after frozen storage and thawing / reheating.

[0038] Throughout the entire preparation process, from raw material selection, cleaning and sterilization to cooking, quick-freezing, and packaging, this invention strictly adheres to a food safety management system. This process ensures that the product's microbiological and physicochemical indicators meet national and corporate internal control standards, providing consumers with safe and healthy food.

[0039] The preparation process employed in this invention, such as advanced equipment like continuous automatic fryers, liquid nitrogen tunnel freezers, and automated packaging lines, combined with precise parameter control, not only ensures the consistency and stability of product quality but also significantly improves production efficiency, enabling large-scale production. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the preparation process of the crayfish and perilla flavored product of the present invention. Detailed Implementation

[0041] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present invention and not to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0043] In the embodiments of the present invention, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of the present invention shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on the present invention; the term "multiple" in the present invention refers to two or more (including two).

[0044] This invention provides a crayfish product with perilla flavor and its preparation process. The aim is to overcome common technical challenges in existing crayfish processing technologies, such as poor meat texture, easy loss of flavor compounds due to volatility, and difficulty in peeling the shell, through a series of synergistically optimized process steps. This results in a quick-frozen crayfish product that, after thawing, has plump and springy meat, is easy to peel, has a rich and lasting perilla flavor, an appealing color, and stable quality. The technical solution of this invention will be described in detail below with specific embodiments to ensure that those skilled in the art can fully understand and implement this invention.

[0045] In one specific embodiment, the preparation process of the crayfish and perilla-flavored product of the present invention includes the following key steps: Step S1: Screening and pretreatment of crayfish raw materials.

[0046] This invention first rigorously screens live crayfish, prioritizing robust, vigorous, disease-free, and undamaged individuals. The crayfish are uniformly sized, with each crayfish weighing between 15-30 grams (approximately 4-8 qian / piece). In actual production, an advanced machine vision system combined with high-precision dynamic weighing and sorting equipment is used for automated grading, ensuring high uniformity in the size of raw materials entering the next process. This uniformity is crucial for subsequent cleaning, flavoring, and cooking stages, ensuring that the crayfish achieve even heating and flavor absorption under the same processing parameters, thus guaranteeing consistent final product quality.

[0047] Further, the screened crayfish undergo a multi-stage cleaning system. The initial cleaning uses ambient temperature running water for rinsing, effectively removing mud, algae, and other large impurities from the crayfish's surface using a high-pressure water gun or a cleaning machine with a roller brush. The subsequent second-stage cleaning incorporates ozone water immersion technology, placing the crayfish in a specially designed cleaning tank equipped with circulating water and an ozone generator. This tank is typically constructed of food-grade stainless steel and equipped with a precisely temperature-controlled cooling system and a highly efficient ozone dissolving device. The ozone generator produces ozone by high-frequency, high-voltage ionization of oxygen in the air, which is then efficiently dissolved in the circulating water through a microporous aeration disc or a Venturi jet, forming ozone water with a concentration of 0.5-1.0 ppm. The immersion cleaning time is controlled at 5-10 minutes, while the water temperature is precisely maintained at 5-10℃. Under these low-temperature conditions, the crayfish's vitality is preserved to the maximum extent. Simultaneously, the strong oxidizing properties of ozone can rapidly kill pathogenic microorganisms on their surface and effectively degrade some organic pollutants, such as earthy-smelling substances, thus achieving deep purification and preliminary sterilization. The low-temperature environment also effectively slows down the crayfish's metabolism, reducing their stress response. Finally, the cleaned crayfish undergo at least two rinses with purified water. Through powerful water flow, ozone residue, dead microbial remains, and fine impurities are thoroughly removed, ensuring the raw material's purity meets the highest standards of food processing.

[0048] After cleaning, the crayfish need to undergo a process of expelling sand and removing their intestines. This step is crucial for improving the product's ease of consumption and safety. The crayfish are transferred to a clean, well-ventilated rearing tank, filled with purified water that has been sterilized by ultraviolet light or filtered through a reverse osmosis membrane, and food-grade refined salt is added at a ratio of 0.1%-0.2% of the water's weight. The addition of salt aims to simulate the crayfish's natural growth environment, promoting intestinal peristalsis and accelerating the expulsion of mud and feces from the digestive tract. The rearing time is strictly controlled to 12-24 hours, during which the water is changed every 6-8 hours, ensuring water circulation to maintain water quality and stimulate the crayfish to continuously expel sand. After the rearing period, the intestinal tract of the crayfish is physically removed using professional automated degumming equipment. This equipment typically includes a sophisticated robotic arm and a vacuum suction device, capable of accurately identifying and completely removing the crayfish's dorsal intestinal tract, avoiding meat damage and inefficiency that can occur with manual operation. This physical method of removing intestines ensures thorough removal of the intestinal tract, fundamentally eliminating the unpleasant odor of mud and sand and potential biological risks, and significantly improving the product's eating experience.

[0049] After the gutting process, the crayfish are quickly conveyed through a draining conveyor belt to remove residual surface moisture, and then undergo further sterilization. This sterilization can be performed using ultraviolet-C (UV-C) irradiation or immersion in hypochlorous acid. If UV-C irradiation is used, the crayfish are evenly spread on a dedicated mesh conveyor belt and passed through a sealed UV-C sterilization chamber. The chamber is equipped with multiple high-intensity, long-life 254nm UV lamps, which are optimally arranged to ensure comprehensive and thorough irradiation of the crayfish surface. The irradiation intensity is precisely controlled within... The irradiation time is 1-2 minutes. UV-C ultraviolet light can effectively destroy the DNA structure of microorganisms, inhibiting their replication and reproduction, thus achieving efficient sterilization. If hypochlorous acid water soaking is chosen, the crayfish are immersed in a hypochlorous acid aqueous solution with an effective chlorine content of 50-100 ppm, prepared by electrolysis or chemical methods, for 1-2 minutes. Hypochlorous acid has a broad-spectrum bactericidal effect, and its bactericidal mechanism mainly involves oxidizing the bacterial cell membrane, penetrating into the cell interior to destroy cell components. Hypochlorous acid water is also mild and has minimal impact on food quality. After soaking, the crayfish must be thoroughly rinsed immediately with plenty of purified water to remove any hypochlorous acid residue and avoid adverse effects on subsequent flavor. The sterilization steps aim to further reduce the microbial load on the surface of the crayfish, providing a safer and more hygienic starting point for subsequent deep processing.

[0050] Step S2: Preparation of perilla flavor concentrate.

[0051] This invention focuses on the careful selection and efficient extraction of perilla leaves in the preparation of perilla flavor concentrate. The perilla leaves are preferably selected from high-quality varieties grown in Hunan Province, China, whose unique growing environment contributes to a higher content of aromatic substances. The timing of harvesting is also crucial, typically from late spring to early summer, harvested after the dew has dried and before noon each day. During this period, the perilla leaves are at their peak due to vigorous photosynthesis and plant metabolism, resulting in the highest content of volatile aromatic substances, especially perillaldehyde, and thus the best quality. The harvested perilla leaves must be bright green, free from pests, diseases, and impurities, and be quickly transported to the processing site for treatment.

[0052] Before extraction, the carefully selected perilla leaves undergo preliminary washing to remove surface dust, followed by draining excess water. They are then chopped into appropriate sizes, such as 2-3 cm pieces, using a professional chopper. This increases the surface area of ​​the perilla leaves, allowing for better contact with steam during subsequent steam distillation and improving the extraction efficiency of aromatic substances. The processed perilla leaves are quantitatively loaded into a food-grade stainless steel steam still, typically featuring a double-jacketed design to ensure uniform heating and equipped with precise pressure and temperature sensors. Saturated steam from an industrial steam boiler is then piped in, with the steam pressure precisely controlled at 0.1-0.2 MPa and the corresponding temperature maintained at 100-105°C. The steam penetrates the perilla leaf layer, carrying out various volatile aromatic substances, including perillaldehyde, limonene, and eugenol, forming a mixture of steam and aromatic compounds. The entire distillation process lasts 3-4 hours until a significant decrease in the aromatic substance content in the condensate is detected, indicating that extraction is nearing completion.

[0053] The mixture of water vapor and aromatic substances is then introduced into a high-efficiency condenser for cooling. The condenser, typically a shell-and-tube or coil design, rapidly lowers the temperature using circulating cooling water, causing the gaseous mixture to condense into a liquid. The condensate is collected and sent to a specially designed oil-water separator. Because perilla essential oil is immiscible with water and its density is generally less than water, it naturally separates into layers in the separator. The upper layer is oily perilla essential oil, pale yellow to colorless, transparent and clear, with the characteristic strong aroma of perilla. The lower layer is perilla hydrosol, an aqueous solution containing a small amount of water-soluble aromatic substances. The essential oil and hydrosol are collected separately through independent outlets at the bottom and top.

[0054] Strict quality testing and standardization of the extracted perilla essential oil and perilla hydrosol are crucial steps to ensure consistent flavor. The core quality indicator for perilla essential oil is the perillaldehyde content, which this invention requires to be no less than 60%. This indicator is quantitatively analyzed using high-precision gas chromatography-mass spectrometry (GC-MS) to ensure the purity and flavor intensity of the perilla essential oil. For perilla hydrosol, the pH value, total solids content, and trace amounts of characteristic aromatic components are primarily tested to assess its flavoring value. Qualified perilla essential oil and perilla hydrosol are stored separately in dark, light-proof, food-grade sealed containers at low temperatures (4-8°C) to minimize oxidation and flavor evaporation, ensuring stability. In practical applications, the perilla flavor concentrate can be used alone or in combination with perilla hydrosol in a specific ratio (e.g., 1:5 to 1:20) according to the product's requirements for flavor intensity and complexity, in order to achieve a richer and more balanced perilla flavor profile.

[0055] Step S3: Preparation of compound spices and formulation of compound seasoning liquid.

[0056] The preparation of the compound spice blend in this invention is a key step in giving crayfish products a unique perilla flavor. First, the core spices undergo meticulous pretreatment.

[0057] Xinjiang cumin, characterized by its plump grains, brownish-yellow color, and rich aroma, is selected as one of the main spices. It undergoes a light roasting process using a drum roaster. Precise temperature sensors and a PID controller maintain the roasting temperature at 120-130℃ for 5-8 minutes. This temperature-controlled roasting effectively stimulates the aromatic precursors within the cumin, releasing its unique and rich aroma while preventing a burnt taste. After roasting, the cumin is rapidly cooled to room temperature and then ground into a fine powder (200 mesh or finer, i.e., particle diameter less than 74 micrometers) using an ultrafine pulverizer (such as an air jet mill or vibratory mill). Ultrafine grinding significantly increases the surface area of ​​the cumin powder, allowing its flavor compounds to be released more fully and quickly in the compound seasoning liquid and evenly distributed throughout the entire product.

[0058] Simultaneously, select Jinyang green Sichuan peppercorns, known for their vibrant green color and rich numbing flavor. Lightly roast them in a stir-fry pan with a stirring function, at a temperature controlled at 100-110℃ for 3-5 minutes. This roasting aims to remove the astringent taste of the green peppercorns and activate their numbing components (such as xanthocyanin). After roasting, quickly cool the peppercorns and grind them into a fine powder below 100 mesh (i.e., particle diameter less than 149 micrometers) using grinding equipment (such as a hammer mill or toothed disc mill). To ensure uniform fineness, further grading and screening using a vibrating screen can be performed to remove coarse particles, guaranteeing the smooth texture of the subsequent compound seasoning liquid.

[0059] The preparation of auxiliary seasonings is equally meticulous. Fresh, plump garlic cloves from Jinxiang, Shandong Province are selected and peeled manually or mechanically, then thoroughly cleaned. The garlic is then processed into minced garlic or garlic paste using a high-speed chopper or colloid mill. The particle size of the minced garlic is precisely controlled to 3-5 millimeters, which not only provides a unique garlic aroma but also adds layers of flavor. This particle size range ensures the full release of the garlic aroma while avoiding the abruptness of overly coarse particles.

[0060] Guizhou Zunyi lantern peppers, known for their bright color and moderate spiciness, are selected. They are then destemmed and seeded to reduce their spiciness and remove impurities. Next, they are dried in a hot air circulating dryer until the moisture content is below 10%, which facilitates preservation and subsequent grinding. The dried lantern peppers are then ground into a coarse powder of 20-40 mesh (i.e., particle diameter between 420-840 micrometers). This coarse powder not only provides a mild spiciness but also gives the finished product an appealing red color, while avoiding the harshness that fine powder might cause.

[0061] This invention also introduces a compound umami-enhancing seasoning to provide rich umami flavor and balance the overall taste, enhancing the aftertaste of the product. The main components of the seasoning are yeast extract (rich in nucleotides and glutamic acid), hydrolyzed vegetable protein (such as hydrolyzed soy protein, providing various amino acids), edible salt, maltodextrin, and disodium inosinate (such as disodium 5'-inosinate and disodium 5'-guanylate). The compound umami-enhancing seasoning is formulated by weight percentage as follows: 35% yeast extract, 25% hydrolyzed vegetable protein, 20% edible salt, 18% maltodextrin, and 2% disodium inosinate. These components work synergistically to produce a significant umami-enhancing effect, and through scientific formulation, can simulate the umami characteristics of natural meat or seafood.

[0062] The preparation of pork bone broth provides a natural umami base and rich flavor for the finished product. Fresh pork bones, such as leg bones and spine bones, are selected, as these bones are rich in collagen and bone marrow. First, they are blanched to thoroughly remove blood and impurities. Then, the blanched pork bones, along with fresh ginger slices and scallion segments, are placed in a pressure cooker with sufficient purified water. This pressure cooker is typically an industrial-grade pressure vessel equipped with a precise pressure and temperature control system. It is cooked at 0.15-0.2 MPa pressure and 115-120℃ for 6-8 hours. High-pressure cooking effectively promotes the dissolution of nutrients and flavor components from the bones, forming a rich bone broth. After cooking, bone residue and spice residue are filtered through a fine mesh to obtain a clear pork bone broth. The broth is then defatted, either by refrigerating and allowing it to settle before skimming off the surface oil or by centrifugation, to reduce the fat content and make the broth clearer. Finally, the bone broth is concentrated to a Brix value of 5-8% using vacuum concentration equipment (such as a multi-effect falling film evaporator). Vacuum concentration is carried out at low temperatures, which effectively preserves the natural flavor compounds of the bone broth and avoids flavor loss or burnt taste that may occur with high-temperature concentration.

[0063] Finally, the compound seasoning liquid is precisely prepared in a clean mixing tank. This tank is typically a jacketed food-grade stainless steel vessel, equipped with a high-shear mixer with variable frequency speed control and a precise temperature control system. Add each component one by one and mix thoroughly according to the following proportions (based on the total mass of the compound seasoning liquid): 0.5%-1.5% perilla essential oil (or a compound liquid of perilla essential oil and perilla hydrosol), 0.8%-1.5% cumin powder, 0.5%-1.0% Sichuan peppercorn powder, 5%-8% minced garlic, 1%-2% coarse bell pepper powder, 2%-3% compound flavor enhancer, 15%-25% concentrated pork bone broth, 8%-12% brewed soy sauce, 4%-6% cooking wine, 1.5%-2.5% salt, 1%-2% white sugar, 1%-1.5% ginger (sliced ​​or grated), 10%-15% edible vegetable oil (such as high oleic sunflower seed oil, which has good antioxidant properties and a light flavor), and purified water to make up the remainder. After all components have been added, start the high-shear mixer for thorough stirring to ensure that all solid powders (such as cumin powder, Sichuan pepper powder, and flavor enhancers) are evenly dispersed and do not clump, and that the liquid components are fully emulsified and blended to form a stable and homogeneous compound seasoning liquid. The stirring process should continue for 20-30 minutes to ensure the homogeneity of the compound seasoning liquid. After preparation, the compound seasoning liquid should be immediately cooled to 0-4°C using a cooling coil or jacket, and then sealed and stored in a light-proof container to minimize the loss and oxidative deterioration of volatile flavor compounds in perilla and other spices.

[0064] Step S4: Low-temperature vacuum tumbling to infuse flavor.

[0065] The marinating process employs advanced low-temperature vacuum tumbling technology to ensure that the compound seasoning liquid can deeply and evenly penetrate into the crayfish meat tissue, while simultaneously optimizing its texture. For this purpose, a horizontal vacuum tumbling machine with refrigeration capabilities and a high-performance vacuum pump is selected. This equipment undergoes thorough cleaning and disinfection before each use, and the interior of the tumbling tank is pre-cooled to 0-4℃ via its built-in jacketed cooling system or direct spraying of refrigerant to maintain a low-temperature environment throughout the marinating process.

[0066] The pre-treated and drained crayfish from step S1, along with the prepared low-temperature compound seasoning liquid from step S3, are added to the tumbling tank of a vacuum tumbling machine at a precise mass ratio of 3:1 to 5:1. After loading, a high-performance vacuum pump is activated to rapidly extract air from the tumbling tank, achieving an absolute pressure of 0.08-0.095 MPa (i.e., a vacuum degree of 90-95%). Under vacuum, the tumbling program is started, with the tumbling tank rotating continuously or intermittently at a speed of 5-10 rpm. During tumbling, the internal temperature of the tumbling tank is precisely maintained at 0-4℃ by an external cooling system. The total tumbling time is controlled to be 2-4 hours. To avoid excessive damage to the crayfish meat due to prolonged mechanical action, the tumbling process is designed to pause for 5-10 minutes every 30 minutes, allowing the crayfish meat to penetrate and recover without mechanical stress.

[0067] The mechanism of the low-temperature vacuum tumbling and flavoring process lies in the synergistic effect of multiple aspects. First, the vacuum environment promotes the expulsion of tiny air bubbles and air from within the crayfish meat tissue, creating negative pressure. When the pressure inside the tumbling tank returns to or near normal atmospheric pressure, the external compound seasoning liquid, under the pressure difference, can penetrate into the gaps in the crayfish meat fibers more quickly and deeply, achieving deep flavoring. This penetration mechanism is significantly superior to atmospheric pressure soaking, effectively locking the aromatic substances of perilla and other spices into the crayfish meat. Second, the consistently low-temperature environment effectively inhibits the growth and reproduction of microorganisms, greatly reducing the risk of spoilage during the flavoring process, while maximizing the preservation of the activity and stability of volatile aromatic substances such as perilla essential oil, avoiding potential oxidation or volatilization loss at room temperature. Furthermore, the mechanical action of tumbling, combined with appropriate vacuum and low temperature, promotes moderate denaturation of myofibril proteins in the crayfish meat, forming a partially gel-like substance, thereby improving the water retention and tenderness of the crayfish meat, resulting in a fuller and more bouncy texture in the final product. More importantly, the physical action during the tumbling process also causes a slight loosening between the shrimp meat fibers and the shrimp shell, laying a good foundation for the easy separation of the shrimp meat from the shell during the subsequent cooking process.

[0068] Step S5: Precisely control the temperature and fry until cooked.

[0069] After being thoroughly tumbled and seasoned at low temperature under vacuum, the crayfish require precise temperature-controlled frying. This step utilizes a continuous automatic fryer equipped with high-precision temperature control and an automatic circulating filtration system to ensure efficient and uniform cooking. The fryer is typically a belt fryer, equipped with multiple independent heating zones and an advanced PID (proportional-integral-derivative) controller. It monitors the oil temperature in real-time using a temperature sensor and precisely adjusts the power output of heating elements (such as electric heating rods or gas burners) to control oil temperature fluctuations within ±2℃, ensuring extremely high temperature stability.

[0070] In terms of oil selection, this invention uses edible vegetable oils with high smoke points and good oxidative stability, such as high-oleic sunflower oil, refined palm oil, or corn germ oil. These oils are rich in monounsaturated or saturated fatty acids, which are not easily oxidized and decomposed at high temperatures, ensuring the stability of oil quality and food safety during frying. The oil level in the fryer's oil tank is precisely controlled at the set level by a liquid level sensor, and an automatic oil replenishment system is equipped to periodically add new oil to maintain the oil's activity and quality. In addition, the fryer also integrates a continuous filtration system (such as a paper belt filter or a mesh belt filter) to remove food residue generated during frying in real time, preventing oil deterioration.

[0071] After the crayfish have been marinated, they are drained of excess compound seasoning liquid via a vibrating conveyor belt, then evenly spread on an automatic conveyor belt and deep-fried in preheated vegetable oil at 160-170℃. The frying time is a critical parameter, precisely controlled between 60-90 seconds. The frying process is controlled by the automatic conveyor belt, which regulates the crayfish's movement speed to ensure each crayfish spends a consistent amount of time in the frying area, resulting in even heating and uniform cooking.

[0072] The core of this precise temperature-controlled frying process lies in the "flash frying" principle, which rapidly solidifies the surface of the crayfish using high temperatures within an extremely short time. Under high temperatures, the proteins on the surface of the crayfish meat quickly denature, forming a dense, microporous protective shell. This shell effectively locks in the moisture and perilla flavor compounds inside the crayfish meat, minimizing juice loss and meat shrinkage and hardening during protein denaturation, thus maintaining the tenderness, plumpness, and springiness of the crayfish meat. This short-time high-temperature treatment also quickly kills any remaining microorganisms on the surface and inside the crayfish, ensuring food safety. Simultaneously, the thermal shrinkage effect during frying creates tiny gaps between the crayfish meat and the shell. This physical change plays a crucial role in the ease of separating the meat from the shell after thawing and reheating. Precise temperature control and timing are key to ensuring the crayfish meat is cooked through but not overcooked, golden and appealing on the outside, while preserving the perilla aroma and avoiding excessive oil absorption. Too short a frying time may result in undercooked meat, while too long a frying time may make the meat too tough or cause a large amount of flavor compounds to evaporate.

[0073] Step S6: Ultra-low temperature quick-freezing preservation.

[0074] After frying, the crayfish are quickly transported to a dedicated cooling area via conveyor belt. This area is typically equipped with powerful fans or a cooling tunnel design, using high-speed cold air or ambient air to rapidly lower the surface temperature of the crayfish from high temperature to room temperature in a short time. Simultaneously, the design of the cooling conveyor belt (such as a mesh belt or perforated plate) helps to thoroughly drain excess oil adhering to the crayfish's surface. This rapid cooling not only helps to stop the internal cooking process of the crayfish meat, preventing overcooking, but also reduces the amount of heat transferred to subsequent quick-freezing equipment, thereby improving quick-freezing efficiency.

[0075] After cooling and draining the oil, the crayfish are evenly spread on the conveyor belt of a liquid nitrogen tunnel freezer and sent into the freezing chamber. The ambient temperature inside the liquid nitrogen tunnel freezer is precisely set within an ultra-low temperature range of -120℃ to -180℃. Through direct spraying of liquid nitrogen or a high-efficiency circulating cold air system, the core temperature of the crayfish is rapidly reduced from room temperature to below -18℃ in a very short time (usually 5-10 minutes). Liquid nitrogen, as a highly efficient refrigerant, is key to achieving rapid freezing due to its extremely low temperature and ultra-fast heat exchange rate.

[0076] The core mechanism of this ultra-low temperature quick-freezing technology lies in maximizing the preservation of the natural quality of crayfish meat. When crayfish undergo ultra-low temperature freezing in a very short time, the water within their cells crystallizes at an extremely rapid rate. This rapid crystallization process results in ice crystals that are extremely small and evenly distributed inside and outside the cells, typically in the form of microcrystals. Unlike traditional slow freezing (which tends to form larger, irregularly shaped ice crystals), these tiny ice crystals cause minimal physical damage to the cell walls of the crayfish meat, effectively preventing structural damage caused by large ice crystals piercing cell membranes. Therefore, during the subsequent thawing process, it can minimize juice loss (i.e., drip rate), maintaining the integrity of the crayfish meat cells and their natural tissue structure. This is crucial for maintaining the springy texture, plumpness, and stable retention of water-soluble flavor substances (such as umami amino acids) in the thawed crayfish meat. Simultaneously, ultra-low temperature effectively inhibits enzyme activity and microbial growth, thereby extending the product's shelf life.

[0077] Step S7: Packaging and Preservation.

[0078] Once quick-frozen, crayfish need to be rapidly portioned and packaged to prevent prolonged exposure to air from affecting quality. The portioning process, based on product specifications and market demand, involves quantitatively packaging a certain number of crayfish and a small amount of accompanying seasoning sauce (which solidifies on the surface or inside the crayfish during frying and freezing) into pre-prepared food-grade composite barrier film bags. These composite barrier film bags are typically composed of multiple layers of materials; for example, an outer layer of polyester (PET) provides good mechanical strength and printability, a middle layer of nylon (PA) provides excellent oxygen barrier properties, and an inner layer of polyethylene (PE) provides good heat-sealing properties and toughness. These multiple layers together ensure excellent oxygen barrier properties. ) and water vapor barrier properties ( It can effectively prevent oxygen penetration from causing fat oxidation and flavor deterioration, as well as water vapor penetration from causing product freezing and quality decline.

[0079] After bagging, the product is vacuum-sealed and heat-sealed using an automated vacuum packaging machine. The machine first uses a high-performance vacuum pump to remove air from the bag, achieving a vacuum level of over 95%, effectively isolating oxygen and inhibiting the growth and reproduction of aerobic microorganisms and the oxidative rancidity of fats, further extending the product's shelf life. Subsequently, the packaging machine precisely heat-seals the bag opening to ensure a tight seal, preventing any external environmental influence on the product.

[0080] Vacuum-packed products are immediately stored in a cold storage facility at -18°C or below. Throughout the subsequent transportation and sales process, this invention strictly adheres to cold chain management standards to ensure that the products are always kept frozen at -18°C or below. This includes using refrigerated trucks for transportation and equipping warehousing and retail stages with standard-compliant refrigeration equipment. This cold chain management aims to maintain optimal product quality, effectively extend its shelf life, and ensure its safe delivery to consumers.

[0081] Example 1: Preparation of crayfish with perilla flavor This embodiment aims to illustrate in detail the specific operation process and parameters for preparing crayfish with perilla flavor according to the technical solution of the present invention.

[0082] 1. Screening and pretreatment of crayfish raw materials: 100 kg of fresh, live crayfish are selected, with each crayfish weighing between 18-25 grams. Visual screening combined with automatic weighing and sorting equipment is used to remove diseased, weak, damaged, or non-standard individuals.

[0083] After screening, the crayfish were placed in batches and rinsed in running clean water at room temperature for 2 minutes to remove surface mud and sand. Then, they were transferred to a cleaning tank equipped with an ozone generator, where the ozone concentration was maintained at 0.8 ppm and the water temperature at 8°C, and soaked for 8 minutes. Afterward, they were rinsed three times with purified water, one minute each time, to thoroughly remove any residue.

[0084] After cleaning, the crayfish are placed in a resting tank filled with purified water and 0.15% (by weight of water) salt, and kept for 18 hours, with the water changed every 6 hours. After resting, the intestinal tract is completely removed using a vacuum-assisted degumming device.

[0085] After being gutted, the crayfish are quickly drained and then sterilized through a UV-C tunnel irradiation system. Irradiation time: 1.5 minutes.

[0086] 2. Preparation of Perilla Flavor Extract: Five kilograms of high-quality perilla leaves harvested from Hunan were selected, washed, drained, and chopped to 2.5 centimeters. The perilla leaves were placed in a stainless steel steam still and distilled for 3.5 hours with saturated steam at 0.15 MPa and 102°C.

[0087] The condensed liquid phase was fed into an oil-water separator, yielding approximately 20 ml of perilla essential oil and 2 liters of perilla hydrosol. GC-MS analysis showed that the perillaldehyde content in the perilla essential oil was 65%. The perilla essential oil and perilla hydrosol were separately sealed and stored at 4°C.

[0088] 3. Preparation of compound spices and formulation of compound seasoning liquid: Select 200 grams of Xinjiang cumin, bake at 125℃ for 6 minutes, cool and grind into a fine powder of 250 mesh.

[0089] Select 150 grams of Jinyang green Sichuan peppercorns, stir-fry at 105℃ for 4 minutes, and grind them into a 120-mesh fine powder after cooling.

[0090] One kilogram of garlic from Jinxiang, Shandong Province, was selected, peeled, and then minced into garlic paste with a particle size of 4 millimeters.

[0091] Select 250 grams of Guizhou Zunyi lantern peppers, remove the stems and seeds, dry them until the moisture content is 8%, and grind them into 30-mesh coarse powder.

[0092] The product uses 300 grams of compound flavor-enhancing seasoning, including 105 grams of yeast extract, 75 grams of hydrolyzed vegetable protein, 60 grams of edible salt, 54 grams of maltodextrin, and 6 grams of disodium inosinate.

[0093] Preparation of concentrated pork bone broth: 10 kg of pork spine bones are blanched and then stewed with ginger and scallions under high pressure for 7 hours (0.18 MPa, 118℃). After filtration and defatting, the broth is vacuum concentrated to a Brix value of 6%.

[0094] Preparation of compound seasoning liquid: Mix precisely in a mixing tank according to the following proportions: Perilla essential oil: 1.0% (mixed with perilla hydrosol at a ratio of 1:10 before use); cumin powder: 1.2%; Sichuan pepper powder: 0.8%; minced garlic: 6.5%; coarsely ground bell pepper: 1.5%; compound umami seasoning: 2.5%; concentrated pork bone broth: 20%; brewed soy sauce: 10%; cooking wine: 5%; salt: 2.0%; white sugar: 1.5%; ginger (ground): 1.2%; high oleic sunflower seed oil: 12%; purified water: balance.

[0095] After all components are added, stir with a high-shear mixer for 25 minutes to form a uniform and stable compound seasoning liquid, and then cool to 3°C.

[0096] 4. Low-temperature vacuum tumbling for flavor infusion: 100 kg of pre-treated crayfish and 25 kg of prepared compound seasoning liquid (crayfish to compound seasoning liquid ratio 4:1) were put into a vacuum tumbler pre-cooled to 2°C.

[0097] Start the vacuum pump to reduce the absolute pressure inside the tank to 0.09 MPa. Maintain a tumbling speed of 7 revolutions per minute and a tumbling temperature of 3°C. The total tumbling time is 3 hours, with a 5-minute pause every 30 minutes.

[0098] 5. Precise temperature control for deep-frying and cooking: After being tumbled and marinated, the crayfish are drained of excess compound seasoning liquid and then sent to a continuous automatic fryer. The frying oil is refined palm oil, and the oil temperature is precisely controlled at 165℃±1℃. The frying time is 75 seconds.

[0099] 6. Ultra-low temperature quick-freezing preservation: After being deep-fried, the crayfish are rapidly cooled to room temperature by powerful fans in the cooling zone and drained of oil. They are then transferred to a liquid nitrogen tunnel freezer with an ambient temperature set at -150°C. Within 8 minutes, the core temperature of the crayfish drops from room temperature to below -20°C.

[0100] 7. Packaging and Storage: The quick-frozen crayfish are packaged in 500g bags into composite barrier film bags (PET / PA / PE structure). The product is vacuum-packed to 96% vacuum and then heat-sealed. The packaged product is immediately stored in a -18°C cold storage.

[0101] The crayfish and perilla-flavored product prepared in this embodiment, after thawing and reheating, presents a golden-red color, a rich perilla aroma, plump and bouncy crayfish meat, a delicious taste with a hint of spiciness and numbing sensation, and the crayfish shell is very easy to peel off.

[0102] This comparative example aims to demonstrate the performance of traditional crayfish products that lack the key technical features of this invention, so as to compare them with the embodiments of this invention.

[0103] Comparative Example A (Perilla Flavor Extract Substitute) This comparative example is used to verify the effectiveness of the perilla flavor extract preparation process (steam distillation extraction) of the present invention. Except for the changes described below, all other steps, parameters, and raw material amounts are exactly the same as in Example 1.

[0104] Variable: Step S2 (steam distillation to extract perilla essential oil and hydrosol) is omitted. Instead, an equal mass (5 kg) of perilla leaves is boiled directly with 10 times its weight of water for 30 minutes, filtered, and the juice is cooled. This perilla juice is then used to replace the proportion of "perilla flavor concentrate (1:10 compound liquid)" in Example 1 (i.e., 1.0% of the total mass of the compound flavoring liquid).

[0105] Comparative Example B (Disassembly of Compound Seasonings) This comparative example was used to verify the synergistic flavor-enhancing effect of the compound flavor-enhancing seasoning and concentrated pork bone broth. Except for the changes described below, all other steps, parameters, and ingredient amounts were exactly the same as in Example 1.

[0106] Variables: In step S3, when preparing the compound seasoning liquid, "compound flavor enhancer" (2.5%) and "concentrated pork bone broth" (20%) are not added. To maintain a consistent total liquid volume, these two components (total 22.5%) are replaced with an equal amount of purified water. That is, the compound seasoning liquid contains only basic seasoning ingredients (soy sauce, salt, sugar, cooking wine, spices, vegetable oil, etc.) and perilla flavor concentrate.

[0107] Comparative Example C (alternative to low-temperature vacuum tumbling process) This comparative example is used to verify the effectiveness of the low-temperature vacuum tumbling process. Except for the changes described below, all other steps, parameters, and raw material amounts are exactly the same as in Example 1.

[0108] Variable: Change "low-temperature vacuum tumbling for flavoring" in step S4 to "room temperature and pressure soaking for flavoring". Specifically: Place the crayfish and the same ratio (4:1) of compound seasoning liquid in a normal pressure container and let it soak at room temperature (25±2℃) for 3 hours, manually turning it several times during the period to ensure even contact. Do not perform vacuuming or tumbling.

[0109] Comparative Example D (Ultra-low temperature quick-freezing process replacement) This comparative example is used to verify the effectiveness of the ultra-low temperature quick-freezing process. Except for the changes described below, all other steps, parameters, and raw material amounts are exactly the same as in Example 1.

[0110] Variable: Change "ultra-low temperature quick-freezing (liquid nitrogen, -150℃, 8 minutes)" in step S6 to "traditional forced-air freezing". Specifically: Place the fried and cooled crayfish in a single layer on a tray and put it into a -25℃ forced-air freezing room for about 180 minutes until the core temperature of the product reaches -18℃.

[0111] Performance comparison data To quantify the beneficial effects of the key technical features of the crayfish and perilla flavored product of this invention, multiple key performance indicators were tested on the products prepared in Example 1 and Comparative Example AD. The results are shown in the table below: Performance comparison data To quantify the superiority of the crayfish and perilla-flavored product of this invention compared to products made using traditional methods, we conducted tests on several key performance indicators of the products from both the implementation and comparative examples. The test results are shown in the table below:

[0112] As can be seen from the comparative data in the table above, the crayfish and perilla flavored product of the present invention is significantly superior to the product prepared by traditional process in several key performance indicators.

[0113] By comparing the data from Example 1 with those from the individual variable comparisons, the following conclusions can be clearly drawn: Comparative Example A (boiled perilla juice): The residual rate of perilla aldehyde (28.5%) was much lower than that of Example 1 (78.2%), and the sensory score decreased significantly. This indicates that the traditional boiling method cannot effectively extract and retain the characteristic flavor substances of perilla, thus proving the necessity and superiority of the present invention to prepare high-purity perilla flavor stock solution by steam distillation.

[0114] Comparative Example B (without compound umami enhancers): While similar to Example 1 in basic physical properties, the overall sensory score was significantly lower, with the evaluation indicating "insufficient umami and short aftertaste." This demonstrates that the synergistic use of compound umami enhancers and concentrated pork bone broth plays an indispensable role in constructing a rich umami flavor profile and a lasting aftertaste, which cannot be replaced by single or basic seasonings.

[0115] Comparative Example C (soaking at room temperature and pressure): Perillaldehyde residue decreased (55.3%), meat firmness increased, and elasticity, peelability, and sensory scores all decreased. This indicates that low temperature and vacuum environments have a synergistic effect in inhibiting flavor volatilization, promoting deep penetration of seasoning liquid, and improving meat tenderness and peelability. Soaking at room temperature and pressure cannot achieve the same flavor absorption and protective effect.

[0116] Comparative Example D (conventional forced-air freezing): The thawing drip rate (8.2%) was much higher than that of Example 1 (2.8%), the elasticity was significantly reduced, and the taste evaluation was worse. This directly proves that the ultra-low temperature quick-freezing technology that forms micro ice crystals can greatly reduce physical damage to shrimp meat cells, thereby effectively reducing juice loss and maintaining the tender and bouncy texture of the meat. Its effect is significantly better than that of traditional freezing methods.

[0117] In summary, this invention integrates and optimizes a series of processes, including the efficient preparation of perilla flavor concentrate, the construction of a composite flavor-enhancing system, low-temperature vacuum tumbling, and ultra-low temperature quick-freezing. These processes work synergistically to solve technical challenges such as flavor loss, poor meat texture, and difficulty in peeling shrimp shells. The comparative examples and data comparisons systematically verify the specific and measurable beneficial effects of each key technical feature, fully demonstrating the inventiveness and technological advancement of this invention.

[0118] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A crayfish and perilla-flavored product, characterized in that, The following components are included by weight: 100 parts crayfish, 0.5-1.5 parts perilla flavor concentrate, 5-10 parts compound spices, 10-15 parts edible vegetable oil, 1.5-2.5 parts salt, 1-2 parts white sugar, 2-3 parts compound flavor enhancer, 8-12 parts brewed soy sauce, 4-6 parts cooking wine, 1-1.5 parts ginger, 5-8 parts garlic, 0.5-1.0 parts Sichuan peppercorns, 0.8-1.5 parts cumin, 1-2 parts chili peppers, and 15-25 parts pork bone broth.

2. A method for preparing a crayfish and perilla-flavored product as described in claim 1, characterized in that, Includes the following steps: Step S1: Screening and pretreatment of crayfish raw materials: Screening, multi-stage cleaning, sand removal, deintestinal removal and sterilization of live crayfish; Step S2: Preparation of perilla flavor concentrate: Perilla leaves are extracted by steam distillation, condensed and separated to obtain perilla essential oil and perilla hydrosol; Step S3: Preparation of compound spices and formulation of compound seasoning liquid: Pre-treat the spices to prepare compound flavor-enhancing seasoning and concentrated pork bone broth, and formulate compound seasoning liquid; Step S4: Low-temperature vacuum tumbling for flavoring: The pre-treated crayfish are tumbled with the compound seasoning liquid under vacuum at a low temperature; Step S5: Precise temperature-controlled deep-frying: Deep-fry the flavorful crayfish in edible vegetable oil at a controlled temperature; Step S6: Ultra-low temperature quick-freezing preservation: The fried crayfish are rapidly cooled and then quick-frozen using an ultra-low temperature method; Step S7: Packaging and Preservation: The quick-frozen crayfish are repackaged, vacuum-packed, and stored in a cold chain.

3. The preparation method according to claim 2, characterized in that: In step S1, select live crayfish weighing 15-30 grams; soak and wash them for 5-10 minutes in ozone water with a concentration of 0.5-1.0 ppm at 5-10℃; and let them stand in pure water containing 0.1%-0.2% salt to expel sand for 12-24 hours, changing the water every 6-8 hours.

4. The preparation method according to claim 2, characterized in that: In step S2, the perilla leaves are chopped to 2-3 cm; steam distillation is carried out at 0.1-0.2 MPa pressure and 100-105℃ for 3-4 hours; the perilla essential oil obtained is not less than 60% perillaldehyde content; the perilla essential oil and perilla hydrosol are sealed and stored at 4-8℃.

5. The preparation method according to claim 2, characterized in that, In step S3, the spice pretreatment includes: Cumin is roasted at 120-130℃ for 5-8 minutes and ground to a finer mesh than 200; Sichuan peppercorns are stir-fried at 100-110℃ for 3-5 minutes and ground to a finer mesh than 100; garlic is made into minced garlic with a particle size of 3-5 mm; chili peppers are dried until the moisture content is less than 10% and ground into a coarse powder of 20-40 mesh.

6. The preparation method according to claim 2, characterized in that: In step S3, the compound flavor-enhancing seasoning is formulated by weight percentage as follows: 35% yeast extract, 25% hydrolyzed vegetable protein, 20% edible salt, 18% maltodextrin, and 2% disodium inosinate. The method for preparing the concentrated pork bone broth is as follows: after blanching pork bones, they are simmered with ginger slices and scallion segments at a pressure of 0.15-0.2 MPa and a temperature of 115-120℃ for 6-8 hours. After filtering and defatting the residue, the broth is concentrated to a Brix value of 5-8%. The compound seasoning liquid is prepared by weight percentage as follows: 0.5%-1.5% perilla essential oil, 0.8%-1.5% cumin powder, 0.5%-1.0% Sichuan peppercorn powder, 5%-8% minced garlic, 1%-2% coarse chili powder, 2%-3% compound flavor enhancer, 15%-25% concentrated pork bone broth, 8%-12% brewed soy sauce, 4%-6% cooking wine, 1.5%-2.5% salt, 1%-2% white sugar, 1%-1.5% ginger, 10%-15% edible vegetable oil, and the remainder is purified water.

7. The preparation method according to claim 2, characterized in that: In step S4, the mass ratio of crayfish to compound seasoning liquid is 3:1 to 5:1; at a temperature of 0-4℃, vacuum is applied to an absolute pressure of 0.08-0.095MPa; the tumbling speed is 5-10 revolutions / minute, the total tumbling time is 2-4 hours, and a 5-10 minute pause is taken every 30 minutes.

8. The preparation method according to claim 2, characterized in that: In step S5, the frying temperature is 160-170℃, and the temperature fluctuation range is controlled within ±2℃; the frying time is 60-90 seconds.

9. The preparation method according to claim 2, characterized in that: In step S6, the crayfish's core temperature is reduced to below -18°C within 5-10 minutes in a liquid nitrogen tunnel freezer at -120°C to -180°C.

10. The preparation method according to claim 2, characterized in that: In step S7, vacuum packaging with a vacuum degree of 95% or higher is used; and the product is stored in a cold storage at a temperature below -18°C.

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