A low-salt tender deer meat vacuum tumbling processing method for group meals

Abstract

This invention relates to a low-salt, tenderizing vacuum tumbling processing method for venison intended for group catering, belonging to the field of meat product processing technology. The method includes raw material pretreatment, preparation of a low-salt nutrient marinade, vacuum tumbling, intermediate settling, a second-stage intermittent tumbling, low-temperature settling and marinating, shaping and heat processing, and cooling and storage. Its advantages include achieving tenderness and moisture retention under low-salt conditions, ensuring that the product maintains good taste and appearance even after heat processing in a central kitchen, followed by refrigeration / freezing and reheating. It is suitable for the process conditions of centralized reheating equipment in group catering, enhances nutritional value, diversifies product forms, and is easy to industrially promote, showing good prospects for industry application.

Description

Technical Field

[0001] This invention belongs to the field of meat processing technology, specifically relating to a vacuum tumbling process for processing venison using vacuum tumbling technology, suitable for centralized processing and reheating in group meals to preserve the tenderness of low-salt venison. Background Technology

[0002] In the group catering sector (schools, enterprises, hospitals, nursing homes, etc.), comprehensive requirements have been placed on meat products in main dishes, including large-scale production, standardization, nutritional balance, and food safety. Venison, especially sika venison, is an ideal source of healthy animal protein due to its low fat content, high protein content, and high proportion of unsaturated fatty acids. However, in practical group catering applications, venison presents the following problems:

[0003] (1) The muscle fibers are dense and easily dry out;

[0004] Venison has fine and dense meat fibers, which can easily lead to significant shrinkage and a tough texture under traditional curing and heating conditions. Especially after concentrated heating and reheating, it becomes dry and tough, which is not conducive to its widespread promotion.

[0005] (2) Traditional methods of improving taste rely on high salt and high oil content;

[0006] To improve the texture and flavor of venison, some processors increase the amount of salt and fat used to enhance its umami and juiciness, which contradicts the current trend in the catering industry of reducing salt and fat intake and advocating healthy eating.

[0007] (3) Centralized processing and reheating lead to quality fluctuations;

[0008] Group meals typically employ a centralized processing model in a central kitchen, cold (frozen) chain distribution, and centralized reheating before serving. Ordinary static marinating or simple stirring marinating processes are difficult to adapt to large-scale processing. Under low-salt conditions, problems such as severe dehydration, high shrinkage, and rough surface are more likely to occur during the reheating stage, resulting in poor batch stability of the product.

[0009] Vacuum tumbling technology has been widely used in the meat processing industry. It promotes the dissolution of salt-soluble proteins through mechanical impact, extrusion, and pressure changes under vacuum, thereby improving the water retention and tenderness of meat products. However, existing technologies mainly focus on conventional meats such as pork and chicken, as well as ham, bacon, and injection-molded products. There is a lack of systematic research on venison, a special raw material, and its low-salt tenderization process in the context of centralized reheating in group meals. Furthermore, the existing vacuum tumbling process parameters have not been specifically optimized for the structural characteristics of venison muscle and the reheating requirements of group meals, which can easily lead to excessive mechanical damage or limited improvement in water retention.

[0010] Therefore, it is necessary to develop a low-salt, tenderizing vacuum tumbling processing method for venison that is suitable for group catering scenarios and can significantly improve the taste and product stability after reheating without relying on high-salt, high-oil, and complex additive systems. Summary of the Invention

[0011] This invention provides a low-salt, tenderizing vacuum tumbling processing method for venison for group catering, which solves the problems of current processing relying on high salt, high oil, and complex additive systems, as well as poor taste and product stability after reheating. Under the condition that the amount of salt added does not exceed 0.8% of the meat weight, the venison products can still maintain good tenderness, juiciness, and shape retention after centralized heat processing and reheating, while meeting the needs of large-scale standardized production in group catering enterprises.

[0012] The technical solution adopted by this invention includes the following steps:

[0013] (1) Raw material pretreatment: Select venison hind leg meat, tenderloin meat or back meat that has passed quarantine, remove the surface fascia, fat and connective tissue, cut into venison chunks or strips with a single weight of 30g to 80g, wash and drain the surface water for later use.

[0014] (2) Preparation of low-salt nutrient marinade: Based on 100 parts by weight of meat, the low-salt nutrient marinade comprises:

[0015] Add 8-15 parts drinking water, 0.4-0.8 parts salt, 0.5-2.0 parts compound plant protein, 0.2-1.0 parts dietary fiber, 0.3-1.0 parts modified starch, 0.2-0.8 parts food-grade organic acid salts, 0.02-0.15 parts natural antioxidants, and 0.2-1.0 parts compound seasonings to drinking water and stir until completely dissolved or evenly dispersed to obtain a low-salt nutritious pickling liquid.

[0016] (3) Vacuum tumbling: The venison processed in step (1) and the marinade prepared in step (2) are placed into a vacuum tumbling machine at a meat:liquid mass ratio of 100:(8~15), the filling rate is controlled at 40~70%, the vacuum is drawn to -0.06~-0.09MPa, and the first stage of continuous tumbling is carried out for 10~30 minutes at a tumbling speed of 6~12r / min;

[0017] (4) Intermediate resting: Stop rolling and let stand for 10 to 30 minutes under vacuum or slight positive pressure to allow the marinade to penetrate evenly.

[0018] (5) Second stage intermittent tumbling: Under the same vacuum conditions as in step (3), intermittent tumbling is carried out in a cycle of tumbling for 5 to 8 minutes and stopping for 3 to 5 minutes, with a total time of 20 to 40 minutes and a tumbling speed of 4 to 10 r / min;

[0019] (6) Low-temperature standing marinating: After tumbling, the venison is left to stand at 0-4℃ for 4-24 hours to allow the protein to fully dissolve and form a stable binding system with water.

[0020] (7) Shaping and heat processing: The venison, after being left to stand and marinate, is divided into portions according to the group meal or in bulk, and placed in trays, lunch boxes or high-temperature resistant packaging bags for vacuum packaging and sealing. It is then heat-processed using hot water or steam at 80-90℃, so that the core temperature of the product reaches 75-80℃ and is kept warm for 3-10 minutes.

[0021] (8) Cooling and storage: The heat-processed venison products are cooled rapidly, and the core temperature of the products is reduced to 10°C or below within 30 to 90 minutes. Then, they are refrigerated at 0 to 4°C or frozen at -18°C or below.

[0022] The compound plant protein in step (2) of the present invention is one or a combination of two or more of soy protein isolate, pea protein, and whey protein.

[0023] In this invention, soy protein isolate and pea protein are blended at a mass ratio of 1:(0.3-1.0).

[0024] In step (2) of this invention, the dietary fiber is one or a combination of two or more of resistant dextrin, inulin, and citrus fiber.

[0025] In step (2) of this invention, the food-grade organic acid salt is one or more of sodium citrate, sodium lactate, and sodium acetate, which is used to adjust pH and enhance water retention.

[0026] In step (2) of this invention, the natural antioxidant is one or more of rosemary extract, tea polyphenols, and tocopherols, in order to improve the color and flavor stability of venison products during refrigerated or frozen storage.

[0027] In step (2) of the present invention, 0.1 to 0.8 parts of compound sugar and, or 0.5 to 3.0 parts of vegetable pulp or vegetable powder are also added.

[0028] In step (2) of this invention, the vegetable pulp or vegetable powder is selected from one or more of carrots, pumpkins, spinach, and beets, and is used to increase the dietary fiber and micronutrient content of the product.

[0029] In step (3) of the present invention, the first stage of continuous tumbling time is preferably 15 to 25 minutes, and the second stage of intermittent tumbling time is preferably 25 to 35 minutes.

[0030] The static marinating time in step (6) of the present invention is 6 to 12 hours.

[0031] This invention achieves low-salt, tender, and stable-output venison products for group catering scenarios by comprehensively optimizing raw material selection, low-salt nutrient marinade formula, vacuum tumbling parameters, static marinating conditions, thermal processing technology, and cooling and storage methods without changing the structure and control system of existing vacuum tumbling equipment.

[0032] Compared with existing conventional marinating or single-stage tumbling methods for processing venison, the present invention has the following advantages:

[0033] (1) Under low salt conditions, the venison retains tenderness and moisture. Under the restriction that the amount of salt added is no more than 0.8% of the meat weight, a stable protein and water network is formed by the synergistic action of compound plant protein, dietary fiber, modified starch and organic acid salts under the action of vacuum tumbling mechanical force, which significantly improves the water retention and tenderness of venison. Cooking loss can be controlled to 15% or less.

[0034] (2) The process for reheating group meals is optimized by using a two-stage vacuum tumbling and static setting process to avoid excessive damage to the structure caused by single long-term tumbling. This ensures that the products can still maintain good taste and appearance after being refrigerated / frozen and reheated in the central kitchen, and adapt to the process conditions of the centralized reheating equipment for group meals.

[0035] (3) Enhanced nutritional value and diversified product forms: The use of plant protein, dietary fiber and vegetable pulp / powder can enhance the protein and dietary fiber content of venison products, while also giving the products a certain natural color and flavor, which is conducive to developing a variety of group meal dishes (venison chunks, venison strips, venison chops, etc.).

[0036] (4) The method used in this invention is easy to promote in industry. This invention does not involve the modification of the structure and control system of the vacuum tumbler. Only the marinating formula and tumbling program are adjusted. It can be directly applied in existing group catering central kitchens or meat processing enterprises, and has good industry promotion value. Attached Figure Description

[0037] Figure 1 This is a flowchart of the present invention;

[0038] Figure 2 This is a TBARS comparison bar chart of the storage stability of this invention;

[0039] Figure 3 This is a bar chart comparing the shear force after reheating according to the present invention;

[0040] Figure 4 This is a bar chart showing the stability of the product after secondary heating according to the present invention. Detailed Implementation

[0041] See Figure 1The process includes the following steps and key technical points:

[0042] (1) Raw material selection and pretreatment

[0043] Firstly, regarding the selection of raw materials, this invention uses venison hind leg meat, tenderloin, and / or loin meat that has passed quarantine inspection as the main raw materials. These cuts have relatively lean muscle tissue, low fat content, and less connective tissue, making them suitable for vacuum tumbling and bulk meal preparation. Preferably, hind leg meat and tenderloin are mixed in any proportion to balance cost and taste. Regarding pretreatment, this invention requires the following operations on the venison raw materials:

[0044] 1) Remove visible fascia, coarse connective tissue and excess fat to reduce deformation and rough texture caused by fascia contraction during processing;

[0045] 2) Cut the venison into chunks or strips with a single weight of 30-80g; preferably, each chunk should weigh 40-60g, so that the chunks can be fully stressed during tumbling without breaking. Wash the cut chunks to remove blood and scum, and then drain the surface water so that there is basically no free water on the surface, which is conducive to the absorption of the marinade and the uniformity of vacuum tumbling.

[0046] Through the above-mentioned raw material selection and pretreatment steps, the present invention provides a suitable muscle matrix for subsequent low-salt tenderizing treatment at the source, creating conditions for uniform penetration of the marinade and effective transfer of the mechanical action of vacuum tumbling.

[0047] (2) Preparation scheme of low-salt nutrient marinade

[0048] A key technical feature of this invention is the design of a low-salt nutritional curing system that organically combines low-salt requirements, water retention and tenderness requirements, and nutritional fortification. While meeting the salt reduction requirements for group meals, it significantly improves the quality stability of venison products.

[0049] The marinating liquid of the present invention comprises the following components based on 100g of meat weight.

[0050] First, the marinating liquid uses drinking water as the base solvent, in an amount of 8–15 parts, preferably 10–12 parts. The drinking water is used to provide the volume of the marinating liquid and serves as a medium for the dissolution, dispersion, and interaction of meat proteins and added plant proteins.

[0051] Secondly, salt is added to the marinade, with a dosage of 0.4 to 0.8 parts, preferably 0.5 to 0.7 parts, so that the total amount of salt added in the finished product does not exceed 0.8% of the meat weight, in order to meet the requirements of group meal processing for salt reduction and sodium control.

[0052] Furthermore, 0.5–2.0 parts of compound plant protein, preferably 1.0–1.5 parts, are added to the marinating solution. The compound plant protein can be selected from one or more of soy protein isolate, pea protein, and whey protein, with a preferred mass ratio of soy protein isolate to pea protein of 1:(0.3–1.0). Under vacuum tumbling conditions, the plant protein can partially swell and form a complex network structure with the meat protein, thereby compensating for the decreased water retention caused by insufficient dissolution of salt-soluble proteins under low-salt conditions.

[0053] The marinating liquid also includes 0.2–1.0 parts of dietary fiber, preferably 0.3–0.8 parts. The dietary fiber can be selected from one or more combinations of resistant dextrin, inulin, and citrus fiber, which can improve the overall water-holding capacity of the system through water absorption and binding, and also increase the dietary fiber content in the product, thus enhancing its nutritional properties. Simultaneously, 0.3–1.0 parts of modified starch, preferably 0.5–0.8 parts, are added to the marinating liquid. The modified starch gelatinizes during subsequent heat processing, forming a gel network with meat and plant proteins to further fix moisture, reduce cooking loss, and improve the juiciness of the finished product.

[0054] To improve the ionic environment and water-retention properties of the protein in the system, 0.2–0.8 parts of food-grade organic acid salts, preferably 0.3–0.6 parts, are added to the marinating solution. The food-grade organic acid salts can be selected from one or more combinations of sodium citrate, sodium lactate, and sodium acetate, and are used to moderately adjust the pH value of the system and increase the ionic strength, thereby improving the swelling and water-retention capacity of meat protein.

[0055] In addition, 0.02 to 0.15 parts of natural antioxidants, preferably 0.05 to 0.10 parts, are added to the marinating liquid. The natural antioxidants can be selected from one or more of rosemary extract, tea polyphenols, and tocopherols, to delay lipid oxidation and color deterioration of venison products during refrigeration or freezing and repeated reheating, which is particularly suitable for application scenarios with long group meal supply cycles.

[0056] To enhance flavor acceptability under low-salt conditions, the marinade also includes 0.2 to 1.0 parts of compound seasoning, preferably 0.3 to 0.7 parts. The compound seasoning contains common spices such as onion powder, garlic powder, pepper powder, and ginger powder, which are used to give venison products a basic flavor suitable for mass group meals and to enhance the overall flavor fullness under low-salt conditions.

[0057] In addition to the above basic formula, the following components may be selectively added to the marinating liquid: First, 0.1 to 0.8 parts of compound sugar, such as a combination of white sugar and maltodextrin, to balance the problem of insufficient saltiness or slight bitterness that may occur under low-salt conditions; Second, 0.5 to 3.0 parts of vegetable pulp or vegetable powder, wherein the vegetable pulp or vegetable powder is selected from one or more of carrots, pumpkins, spinach, and beets, to increase the content of vitamins, dietary fiber and natural pigments in the product, while improving the color of the finished product and the nutritional label attributes.

[0058] The above components are added to drinking water in a predetermined ratio and thoroughly mixed by stirring or high-speed shearing until completely dissolved or evenly dispersed, forming a uniform and stable low-salt nutritious marinating solution. By organically combining compound plant protein, dietary fiber, modified starch, and organic acid salts, this invention achieves water retention and tenderness close to or even superior to traditional high-salt cured venison while significantly reducing salt usage. This marinating system constitutes one of the core formula innovations that distinguish this invention from existing technologies.

[0059] (3) Optimization of vacuum tumbling segmented process and parameters

[0060] Another key technical feature of this invention is the use of a segmented process combining two-stage vacuum tumbling with intermediate resting. This process addresses the characteristics of venison muscle tissue—dense structure, low fat content, and susceptibility to drying out under low-salt conditions—and, in conjunction with the practical needs of centralized processing and reheating for bulk meals, optimizes the tumbling time, drum speed, filling rate, and vacuum level in an integrated manner. This ensures moisture retention and tenderness while avoiding excessive damage to the meat structure. The specific process is as follows:

[0061] 1) Loading and vacuum control

[0062] The pre-treated venison and the prepared low-salt nutrient marinade are added together into a vacuum tumbler at a mass ratio of meat:liquid = 100:(8-15). The drum filling rate is controlled at 40-70%, preferably 50-65%, to ensure that the venison has sufficient space for tumbling and collision within the drum, while avoiding excessive impact force due to insufficient filling, which could cause damage or breakage of the meat pieces at the edges.

[0063] The tumbler is then evacuated to -0.06 to -0.09 MPa, preferably -0.07 to -0.08 MPa, using a vacuum system. Within this vacuum range, air can be effectively released from the venison tissue, which facilitates the penetration of the marinade into the meat under pressure difference. Simultaneously, it reduces oxygen involvement in lipid oxidation and color deterioration, providing a stable processing environment for subsequent tumbling.

[0064] 2) First stage: continuous rolling and kneading

[0065] Under the aforementioned vacuum conditions, the first stage of continuous tumbling treatment is carried out. The drum speed is set to 6–12 r / min, and the tumbling time is 10–30 min, with the preferred speed being 8–10 r / min and the time being 15–25 min.

[0066] The main functions of the first stage of continuous tumbling are: first, to initially promote the penetration of the marinade into the meat through the tumbling and mechanical impact of the rollers; second, to activate and dissolve some salt-soluble proteins and added plant proteins under low-salt conditions, laying the foundation for the formation of a stable protein-water binding system; and third, to moderately loosen the structure of the venison muscle, causing the dense muscle fibers to initially separate and loosen, creating favorable conditions for subsequent processing stages.

[0067] (4) Intermediate resting stage

[0068] After the first stage of continuous tumbling is completed, stop the tumbling operation and perform intermediate standing treatment under vacuum or slight positive pressure for 10 to 30 minutes, preferably 15 to 25 minutes.

[0069] The intermediate resting stage allows the marinade to diffuse further into the meat block through concentration gradient and capillary action without strong mechanical disturbance, which helps improve the uniformity of marinating. At the same time, this resting process can effectively buffer the mechanical stress brought about by continuous tumbling, avoiding damage to the edges and corners of the meat block, rough surface, or excessive structural damage caused by prolonged uninterrupted tumbling.

[0070] (5) Second stage intermittent rolling

[0071] After settling, the second stage of intermittent tumbling is carried out under essentially the same vacuum conditions (-0.06 to -0.09 MPa) as described above. The intermittent tumbling adopts the following mode: tumbling for 5 to 8 minutes, stopping for 3 to 5 minutes, and repeating the cycle, with a total tumbling time of 20 to 40 minutes, preferably 25 to 35 minutes; the drum speed is set to 4 to 10 r / min, preferably 6 to 8 r / min.

[0072] The main purpose of the second stage of intermittent tumbling is to gradually reach a dynamic equilibrium in the processes of protein dissolution, marinade absorption, and the loosening of the surface and internal tissues of the meat, without causing further serious damage to the meat structure. The downtime during intermittent tumbling facilitates the redistribution of moisture within the meat and promotes the gradual formation of the protein network, thereby obtaining venison products that are both tender and retain their shape.

[0073] The overall effect of segmented vacuum tumbling process:

[0074] Through the segmented vacuum tumbling process of loading and vacuum control, continuous tumbling in the first stage, and intermittent tumbling in the second stage, the present invention fully utilizes the positive effects of vacuum tumbling in promoting the penetration of marinade, protein dissolution, and water retention and tenderness, while effectively avoiding the adverse consequences of excessive tumbling, such as meat fragmentation, severe dehydration, and structural damage.

[0075] This segmented tumbling process is particularly suitable for venison raw materials with dense muscle tissue and low fat content. It can still achieve good tenderness, juiciness and shape stability under low-salt processing conditions, providing a reliable process guarantee for centralized processing and reheating of group meals.

[0076] (6) Low-temperature static pickling

[0077] After vacuum tumbling, the present invention further employs a low-temperature static marinating step to fully redistribute the marinade and dissolved proteins that have entered the meat block, forming a stable protein-moisture-polysaccharide complex network.

[0078] Specifically, the tumbled venison is left to stand at 0–4°C for 4–24 hours, preferably 6–12 hours. During this standing period, the plant protein, dietary fiber, and modified starch in the marinade further interact with the meat protein and water to form a stable three-dimensional network structure, which improves the water retention and tenderness of the venison products during subsequent heat processing and reheating.

[0079] (7) Molding and heat treatment

[0080] In the forming and heat processing steps, the method of the present invention can select bulk or quantitative portioning for plating / boxing according to different group catering application scenarios. Preferably, the venison is packaged into trays, lunch boxes or high-temperature resistant packaging bags at a standard of 40-80g per portion, laid flat in a single or double layer and then vacuum-sealed to facilitate centralized heat processing and unified output in the central kitchen of the group catering enterprise.

[0081] During heat processing, hot water or steam at 80–90°C is used for heating until the core temperature of the venison product reaches 75–80°C, and this temperature is maintained for 3–10 minutes, preferably 76–78°C for 4–6 minutes. Within this temperature range, meat and plant proteins fully coagulate, while modified starch gelatinizes and dietary fiber absorbs water and swells. These three factors work together to form a stable gel system, thereby minimizing cooking losses and ensuring the juiciness of the venison product.

[0082] (8) Cooling and storage

[0083] After heat treatment, this invention emphasizes the importance of rapid cooling and suitable storage conditions. By reducing the core temperature of the product to 10°C or below within 30–90 minutes, and preferably to below 8°C within 40–60 minutes, microbial growth can be effectively inhibited and quality deterioration can be slowed down.

[0084] Based on the delivery radius and meal supply cycle of catering companies, this invention provides two storage solutions:

[0085] Refrigeration solution: Store for 1-3 days under refrigeration conditions of 0-4℃ for same-city or short-distance group meal delivery;

[0086] Freezing solution: The product is rapidly frozen to a core temperature not higher than -18°C under quick-freezing conditions, and then stored at -18°C or below for cross-regional distribution or medium- to long-term storage.

[0087] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0088] Example 1: Low-salt, tender venison chunks for company canteen group meals

[0089] 1. Raw material pretreatment: Select hind leg meat of sika deer that has passed quarantine, remove the surface fascia and coarse connective tissue, cut into pieces of about 2×3×4cm, each piece weighing about 40-60g, wash and drain for later use.

[0090] 2. Low-salt nutrient curing solution formula (based on 100kg of meat):

[0091] Drinking water: 10kg;

[0092] Salt: 0.6 kg;

[0093] Soy protein isolate: 1.2kg;

[0094] Pea protein: 0.5kg;

[0095] Resistant dextrin: 0.4 kg;

[0096] Inulin: 0.3 kg;

[0097] Modified starch: 0.8 kg;

[0098] Sodium citrate: 0.4 kg;

[0099] Sodium lactate: 0.2 kg;

[0100] Rosemary extract: 0.08 kg;

[0101] Compound seasoning (onion powder, garlic powder, black pepper powder, etc.): 0.5kg;

[0102] Complex sugar (white sugar: maltodextrin = 1:1): 0.4 kg;

[0103] Carrot puree: 2.0 kg;

[0104] Add the above ingredients to drinking water in order and stir until there are no obvious particles to obtain an orange-yellow low-salt nutrient pickling liquid.

[0105] 3. Vacuum Tumbling Process

[0106] Filling: Add 100kg of venison chunks and 10kg of marinade to a vacuum tumbler, controlling the filling rate at 60%. Vacuuming: Vacuum to -0.075MPa. First stage continuous tumbling: Rotation speed 8r / min, continuous tumbling for 20min.

[0107] 4. Intermediate standing: Maintain vacuum and let stand for 20 minutes.

[0108] 5. Second stage intermittent tumbling: speed 6r / min, tumbling for 6min and stopping for 4min, cycled 4 times, for a total time of 40min.

[0109] 6. Low-temperature static marinating

[0110] After tumbling, transfer the venison along with the marinade into a stainless steel tray and let it stand in a cold storage at 0-4℃ for 8 hours.

[0111] 7. Molding and Heat Treatment

[0112] Divide the marinated venison into shallow dishes of about 60g each, spreading them out in a single layer as much as possible, and cover with aluminum foil or seal with a high-temperature resistant film; place in a steam box and heat with 85℃ steam until the center temperature of the venison reaches 78℃ and keep warm for 5 minutes.

[0113] 8. Cooling and Storage

[0114] Immediately after heat processing, the meat is transferred to a cooling room where it is rapidly cooled using a combination of cold air and cold water spray, reducing the core temperature to below 8°C within 40 minutes. The cooled venison platter is then refrigerated at 0–4°C and can be stored for up to 3 days for use in group meals.

[0115] See Figure 2Under identical formulation conditions, the addition of natural antioxidants was compared (E: 0.08% rosemary extract added; F: no addition). TBARS results showed that after 7 days of refrigeration and reheating, group E had 0.36±0.04 mg MDA / kg, and group F had 0.71±0.06 mg MDA / kg; after 90 days of frozen storage at -18℃ and reheating, group E had 0.35±0.03 mg MDA / kg, and group F had 0.69±0.05 mg MDA / kg. These results indicate that the addition of natural antioxidants significantly delays lipid oxidation during storage and reheating, improving flavor and color stability.

[0116] This invention provides a reheating process adaptation solution suitable for group catering scenarios.

[0117] Venison products that have been refrigerated or thawed from freezing can be reheated in a steam reheating box, combination oven, or hot air circulation equipment at 85-95°C for 10-25 minutes until the core temperature of the product is not lower than 70°C. Thanks to the aforementioned low-salt nutrient curing system and segmented vacuum tumbling process, the venison products produced by this invention retain good tenderness and water retention after reheating, with cooking loss generally not exceeding 15%. They exhibit minimal water separation in the dish, and the meat pieces retain their intact shape, making them suitable for centralized supply in various group catering scenarios such as school canteens, corporate canteens, hospitals, and elderly care institutions. For example:

[0118] Reheating supply:

[0119] Before serving, the refrigerated venison platter was placed directly into a steam reheating box and reheated with 90℃ steam for 15 minutes. According to sensory evaluation, the venison products were reddish in color, moist on the cut surface, with a small amount of meat juice seeping out, tender in texture, moderately elastic, and not dry when chewed.

[0120] Quality inspection results:

[0121] See Figure 4 The quality of the samples prepared in Example 1 was tested under group catering conditions (n=3 batches, mean ± SD), and the results are as follows:

[0122] Stability of products after secondary heating: In Group A of this invention (low-salt nutrient marinating solution + two-stage vacuum tumbling + standing), the total loss rate after reheating was 13.3±0.6%, and the water separation in the pan was 1.6±0.2%. In Group B, the low-salt static marinating rates were 24.6±1.0% and 4.9±0.4%, respectively. In Group C, the low-salt single-stage continuous tumbling rates were 18.4±0.7% and 3.1±0.3%, respectively. In Group D, the traditional high-salt rates were 19.8±0.9% and 3.6±0.4%, respectively. The results show that this invention can stably control the total loss rate after secondary heating to within 15% under low-salt conditions, and significantly reduce water separation.

[0123] Example 2: Low-salt, tender venison chunks for company canteen group meals

[0124] 1. Raw material pretreatment: Select hind leg meat of sika deer that has passed quarantine, remove the surface fascia and coarse connective tissue, cut into pieces, each weighing about 60-80g, wash and drain for later use.

[0125] 2. Low-salt nutrient curing solution formula (based on 100kg of meat):

[0126] Drinking water: 15kg;

[0127] Salt: 0.8 kg;

[0128] Soy protein isolate: 2.0 kg;

[0129] Resistant dextrin: 1.0 kg;

[0130] Modified starch: 1.0 kg;

[0131] Sodium citrate: 0.8 kg;

[0132] Rosemary extract: 0.04 kg;

[0133] Tea polyphenols: 0.07 kg;

[0134] Tocopherol: 0.04 kg;

[0135] Compound seasoning (onion powder, garlic powder, black pepper powder): 1.0 kg;

[0136] Complex sugar (white sugar: maltodextrin = 1:1): 0.8 kg;

[0137] Carrot puree: 1.5kg;

[0138] Pumpkin powder: 0.5kg;

[0139] Spinach powder: 1.0 kg;

[0140] Add the above ingredients to drinking water in order and stir until there are no obvious particles to obtain a low-salt nutrient pickling solution.

[0141] 3. Vacuum Tumbling Process

[0142] Filling: Add 100kg of venison chunks and 15kg of marinade to a vacuum tumbler, controlling the filling rate at 70%. Vacuuming: Vacuum to -0.09MPa. First stage continuous tumbling: Rotation speed 12r / min, continuous tumbling for 30min.

[0143] 4. Intermediate standing: Maintain vacuum and let stand for 30 minutes.

[0144] 5. Second stage intermittent tumbling: 10 r / min speed, tumbling for 5 min and stopping for 5 min twice, for a total time of 20 min.

[0145] 6. Low-temperature static marinating

[0146] After tumbling, transfer the venison along with the marinade into a stainless steel tray and let it stand in a cold storage at 0-4℃ for 24 hours.

[0147] 7. Molding and Heat Treatment

[0148] Divide the marinated venison into shallow dishes of about 90g each, spreading them out in a single layer as much as possible, and cover with aluminum foil or seal with a high-temperature resistant film; place in a steam box and heat with 90℃ steam until the center temperature of the venison reaches 80℃ and keep warm for 3 minutes.

[0149] 8. Cooling and Storage

[0150] Immediately after heat processing, the meat is transferred to a cooling room where it is rapidly cooled using a combination of cold air and cold water spray, ensuring the core temperature drops below 10°C within 90 minutes. The cooled venison platters are then frozen and stored at -18°C or below for use in group meals.

[0151] Example 3: Low-salt, tender venison chunks for company canteen group meals

[0152] 1. Raw material pretreatment: Select hind leg meat of sika deer that has passed quarantine, remove the surface fascia and coarse connective tissue, cut into pieces, each weighing about 30-40g, wash and drain for later use.

[0153] 2. Low-salt nutrient curing solution formula (based on 100kg of meat):

[0154] Drinking water: 8kg;

[0155] Salt: 0.4 kg;

[0156] Whey protein: 0.2 kg;

[0157] Pea protein: 0.3kg;

[0158] Citrus fiber: 0.1kg;

[0159] Inulin: 0.1 kg;

[0160] Modified starch: 0.3 kg;

[0161] Sodium acetate: 0.1 kg;

[0162] Sodium lactate: 0.1 kg;

[0163] Rosemary extract: 0.01 kg;

[0164] Tea polyphenols: 0.01 kg;

[0165] Compound seasoning (onion powder, black pepper powder): 0.2kg;

[0166] Add the above ingredients to drinking water in order and stir until there are no obvious particles to obtain a low-salt nutrient pickling solution.

[0167] 3. Vacuum Tumbling Process

[0168] Filling: Add 100kg of venison chunks and 8kg of marinade to a vacuum tumbler, controlling the filling rate at 40%. Vacuuming: Vacuum to -0.06MPa. First stage continuous tumbling: Rotation speed 6r / min, continuous tumbling for 10min.

[0169] 4. Intermediate standing: Maintain vacuum and let stand for 10 minutes.

[0170] 5. Second stage intermittent tumbling: speed 4r / min, 3 cycles of tumbling for 8min and stopping for 3min, for a total time of 33min.

[0171] 6. Low-temperature static marinating

[0172] After tumbling, transfer the venison along with the marinade into a stainless steel pan and let it stand in a cold storage at 0-4℃ for 4 hours.

[0173] 7. Molding and Heat Treatment

[0174] Divide the marinated venison into shallow dishes of about 50g each, spreading them out in a single layer as much as possible, and cover with aluminum foil or seal with a high-temperature resistant film; place in a steam box and heat with 80℃ steam until the center temperature of the venison reaches 75℃ and keep warm for 10 minutes.

[0175] 8. Cooling and Storage

[0176] After the heat treatment is completed, the meat is immediately sent to the cooling room, where cold air and cold water spray are used to quickly cool it down so that the core temperature drops to below 9°C within 30 minutes. The cooled venison platter is then refrigerated at 0-4°C and can be stored for up to 3 days for group meals.

[0177] Example 4: Low-sodium venison strips for school catering

[0178] This embodiment is basically the same as Embodiment 1, except for adjustments to the raw material form, formula, and some process parameters:

[0179] 1. The raw material is sika deer tenderloin, cut into strips about 6-8cm long and 1.5-2.0cm wide;

[0180] 2. The total amount of plant protein in the marinade was reduced to 1.2 parts by weight based on the weight of the meat, the dietary fiber was 0.5 parts by weight of citrus fiber, complex sugars were removed, and 1.5 parts by weight of pumpkin powder was added;

[0181] 3. The vacuum degree is -0.07MPa, the first stage of continuous tumbling time is 15min, and the second stage of intermittent tumbling total time is 25min;

[0182] 4. The low-temperature standing marinating time is 6 hours;

[0183] 5. During hot processing, vacuum packaging is used followed by water bath heating at a temperature of 82℃, with the core temperature reaching 76℃ and held for 4 minutes.

[0184] The resulting venison strips are suitable for serving with rice or as a main dish in student group meals when paired with vegetables. They remain tender after refrigeration and reheating, and have a moderate overall saltiness.

[0185] Example 5: Venison chunks for frozen group meals

[0186] Based on Example 1, the cooling and storage method was adjusted to freezing:

[0187] 1. After hot working, cool to below 4°C within 45 minutes;

[0188] 2. Enter the quick-freezing tunnel and quick-freeze at -30℃ until the core temperature of the product does not exceed -18℃;

[0189] 3. Can be stored for 3 months in a -18℃ cold storage;

[0190] 4. No need to thaw completely before use. You can directly heat it in the combination oven at 85-90℃ hot air for 20-25 minutes until the center temperature is ≥70℃.

[0191] Sensory and loss rate tests show that the frozen venison products prepared by the method of the present invention maintain good tenderness and water retention after multiple freeze-thaw cycles and reheating, making them suitable for cross-regional or multi-point group meal delivery.

[0192] The following experimental examples will further illustrate the effects of the present invention.

[0193] Experimental example: Verification of venison tenderness after reheating

[0194] Central kitchens for group meals often adopt a supply model of "centralized processing, cold (frozen) chain distribution, and reheating before serving." Venison, due to its dense muscle fibers, experiences tissue shrinkage, dehydration, and a dry texture during reheating, leading to difficulty in chewing, poor palatability, low batch size, and low fat content. It is also more prone to large fluctuations under low-salt conditions. This experiment uses tenderness after reheating as the evaluation endpoint, employing objective indicators such as shear force and texture to verify the effect of the "low-salt curing + two-stage vacuum tumbling + low-temperature static curing" process described in this invention on improving tenderness, and compares it with low-salt static curing, low-salt single-stage continuous tumbling, and traditional high-salt processes.

[0195] (I) Materials and Methods

[0196] (1) Raw materials

[0197] The raw material was hind leg meat of deer that had passed quarantine inspection. After removing the surface fascia and coarse connective tissue, it was cut into commonly used block shapes for group meals, with a thickness of 10–12 mm and a single block weight of 40–60 g. The block shape, weight distribution and processing procedures of each group of samples were kept consistent to reduce interference from non-process factors.

[0198] (2) Process flow

[0199] Four control groups were set up (sample codes A~D): Group A was the process treatment group of Example 1 of this invention. This group used a low-salt curing solution for curing, and the amount of salt added was controlled at 0.6% by weight of meat. A two-stage vacuum tumbling process was introduced during the curing process. First, continuous tumbling was performed, followed by intermediate resting under vacuum or near-vacuum conditions, and then intermittent tumbling was performed again. After tumbling, the samples were placed in a refrigerator at 0 to 4 degrees Celsius for static curing to ensure that the curing solution and protein system were fully redistributed and stably combined.

[0200] Group B served as a low-salt static control group: This group used the same low-salt pickling solution as Group A, with the same amount of salt added and formula composition to eliminate the influence of salinity and formula differences on the results. This group did not undergo vacuum tumbling; instead, the pickled samples were placed in a refrigerated environment at 0 to 4 degrees Celsius for static pickling, allowing the pickling process to be mainly completed through static osmosis.

[0201] Group C served as the low-salt single-stage tumbling control group: This group used the same low-salt pickling solution as Group A, with the same amount of salt added and formula composition, and under the same vacuum conditions as Group A for tumbling. The difference was that this group used a single-stage, long-duration continuous tumbling method to complete the pickling process, without an intermediate resting stage or intermittent tumbling program, to compare and verify the effects of segmented tumbling versus intermediate resting.

[0202] Group D served as the traditional high-salt control group: This group increased the salt content during the curing stage by approximately 1.8% by meat weight, representing the traditional method that relies on higher salt concentrations to improve flavor and texture. This group did not undergo vacuum tumbling; instead, it used a static curing method to compare and verify the advantages of this invention in achieving tenderness through process optimization under low-salt conditions. A standardized simulated group meal supply chain was used: centralized heat processing (central 76–78℃ holding for 4–6 min) → rapid cooling → refrigeration at 0–4℃ for 24 h → reheating in a steam reheater at 90℃ for 15 min. All tests were conducted on the "finished product after reheating" to ensure that the evaluation results directly corresponded to the actual eating experience at the group meal end.

[0203] (3) Key parameters of vacuum tumbling

[0204] The specific parameters used in the experiment are as follows: vacuum degree -0.07~-0.08 MPa; filling rate 60%; tumbling program for Group A: first stage continuous 8 r / min×20 min; resting for 20 min in the middle; second stage intermittent 6 r / min, 6 min rolling / 4 min rest, cycled 4 times; Group C used continuous tumbling for 60 min.

[0205] (4) Detection indicators and methods

[0206] 1) Shear force: Using a texture analyzer equipped with a Warner-Bratzler shearing head, strip-shaped samples of uniform size were taken from the center of the sample, with uniform fiber direction / cutting direction, and the peak shear force was recorded. Ten samples were taken from each batch and each group, and the mean was calculated.

[0207] 2) Texture TPA: Two compression tests were conducted using a texture analyzer, and the hardness and chewiness were recorded.

[0208] 3) Statistics: Each group must have at least 3 batches of independent processing repeated (n=3).

[0209] (II) Results and Analysis

[0210] (1) Shear force results after reheating (n=3, mean ±SD)

[0211] The results are shown in Table 1. Group A had the lowest shear force, indicating that it was the easiest to chew after reheating. Group B had the highest shear force, suggesting that static pickling alone under low-salt conditions could not prevent hardening after reheating. Group C was better than Group B, but not as good as Group A, indicating that tumbling is not necessarily better the longer it is done. Segmented tumbling and intermediate resting can better balance penetration and structural protection. The shear force of Group A was still about 15-20% lower than that of Group D, proving that the present invention can achieve better tenderness without relying on "adding salt".

[0212] Table 1 Shear force after reheating

[0213] A. This invention group Low salt + segmented vacuum tumbling + resting 33.2 ± 2.1 — B Low-salt static Low salt + resting, no tumbling 44.0 ± 2.8 ↑ Approximately 24% C. Low-salt single-stage tumbling Low salt + continuous long rolling 37.2 ± 2.2 ↑ Approximately 12% D Traditional high-salt High-salt static 40.1 ± 2.4 ↑ Approximately 17%

[0214] See Figure 3 Objective indicators of tenderness: Shear force (Warner-Bratzler) was measured on the reheated samples. The shear force of group A of this invention was 33.2±2.1 N; group B with low-salt static curing was 44.0±2.8 N; group C with low-salt single-stage continuous tumbling was 37.2±2.2 N; and group D with traditional high-salt was 40.1±2.4 N. The shear force of the group of this invention was reduced by about 17% compared with the traditional high-salt control and by about 24% compared with the low-salt static control, indicating that this invention can significantly improve the tenderness of venison under low-salt conditions.

[0215] (2) Texture results after reheating

[0216] The TPA results are consistent with the shear force trend. Group A has the lowest hardness and chewiness, reflecting that the tissue is more easily compressed and chewed after reheating, which is more in line with the group meal requirements of "eating-friendly and batch consistency", and is especially suitable for students, the elderly and other people who are sensitive to tenderness.

[0217] Table 2 Texture test results

[0218] A. This invention group 41.5 ± 3.0 18.6 ± 1.4 The softest and easiest to chew B Low-salt static 56.8 ± 4.2 27.3 ± 2.0 Hard and chewy C. Low-salt single-stage tumbling 48.9 ± 3.6 22.4 ± 1.7 Moderate improvement D Traditional high-salt 50.7 ± 3.9 23.8 ± 1.8 Limited improvement

[0219] (III) Conclusion

[0220] Under real-world conditions, the shear force of the group using this invention after reheating was 33.2±2.1 N, significantly lower than that of the low-salt static curing group (44.0±2.8 N), the low-salt single-stage continuous tumbling group (37.2±2.2 N), and the traditional high-salt static group (40.1±2.4 N). Simultaneously, the TPA hardness and chewiness were 41.5±3.0 N and 18.6±1.4 N, respectively, both the lowest among all groups. The results indicate that, under controlled salt addition conditions, this invention, through the synergistic effect of segmented vacuum tumbling and static infiltration, can significantly improve the tenderness and chewiness of venison after secondary reheating without relying on increased salinity, and enhances the batch stability and end-product palatability of group meals.

Claims

1. A vacuum tumbling processing method for low-salt, tenderizing venison for group meals, characterized in that, Includes the following steps: (1) Raw material pretreatment: Select venison hind leg meat, tenderloin meat or back meat that has passed quarantine, remove the surface fascia, fat and connective tissue, cut into venison chunks or strips with a single weight of 30g to 80g, wash and drain the surface water for later use. (2) Preparation of low-salt nutrient marinade: Based on 100 parts by weight of meat, the low-salt nutrient marinade comprises: Add 8-15 parts drinking water, 0.4-0.8 parts salt, 0.5-2.0 parts compound plant protein, 0.2-1.0 parts dietary fiber, 0.3-1.0 parts modified starch, 0.2-0.8 parts food-grade organic acid salts, 0.02-0.15 parts natural antioxidants, and 0.2-1.0 parts compound seasonings to drinking water and stir until completely dissolved or evenly dispersed to obtain a low-salt nutritious pickling liquid. (3) Vacuum tumbling: The venison processed in step (1) and the marinade prepared in step (2) are placed into a vacuum tumbling machine at a meat:liquid mass ratio of 100:(8~15), the filling rate is controlled at 40~70%, the vacuum is drawn to -0.06~-0.09MPa, and the first stage of continuous tumbling is carried out for 10~30 minutes at a tumbling speed of 6~12r / min; (4) Intermediate resting: Stop rolling and let stand for 10 to 30 minutes under vacuum or slight positive pressure to allow the marinade to penetrate evenly. (5) Second stage intermittent tumbling: Under the same vacuum conditions as in step (3), intermittent tumbling is carried out in a cycle of tumbling for 5 to 8 minutes and stopping for 3 to 5 minutes, with a total time of 20 to 40 minutes and a tumbling speed of 4 to 10 r / min; (6) Low-temperature standing marinating: After tumbling, the venison is left to stand at 0-4℃ for 4-24 hours to allow the protein to fully dissolve and form a stable binding system with water. (7) Shaping and heat processing: The venison, after being left to stand and marinate, is divided into portions according to the group meal or in bulk, and placed in trays, lunch boxes or high-temperature resistant packaging bags for vacuum packaging and sealing. It is then heat-processed using hot water or steam at 80-90℃, so that the core temperature of the product reaches 75-80℃ and is kept warm for 3-10 minutes. (8) Cooling and storage: The heat-processed venison products are cooled rapidly, and the core temperature of the products is reduced to 10°C or below within 30 to 90 minutes. Then, they are refrigerated at 0 to 4°C or frozen at -18°C or below.

2. The vacuum tumbling processing method for low-salt, tender venison for group meals according to claim 1, characterized in that, In step (2), the compound plant protein is a mixture of soy protein isolate and pea protein in a mass ratio of 1:(0.3-1.0).

3. The vacuum tumbling processing method for low-salt, tender venison for group meals according to claim 1, characterized in that, In step (2), the dietary fiber is one or a combination of two or more of the following: resistant dextrin, inulin, and citrus fiber.

4. The vacuum tumbling processing method for low-salt, tender venison for group meals according to claim 1, characterized in that, In step (2), the food-grade organic acid salt is one or more of sodium citrate, sodium lactate, and sodium acetate, which is used to adjust pH and enhance water retention.

5. A vacuum tumbling processing method for low-salt, tender venison for group meals according to claim 1, characterized in that, In step (2), the natural antioxidant is one or more of rosemary extract, tea polyphenols, and tocopherols, in order to improve the color and flavor stability of venison products during refrigerated or frozen storage.

6. A vacuum tumbling processing method for low-salt, tenderizing venison for group meals according to any one of claims 1 to 5, characterized in that, In step (2), 0.1 to 0.8 parts of compound sugar and / or 0.5 to 3.0 parts of vegetable pulp or vegetable powder are also added.

7. A vacuum tumbling processing method for low-salt, tender venison for group meals according to claim 6, characterized in that, In step (2), the vegetable pulp or vegetable powder is selected from one or more of carrots, pumpkins, spinach, and beets, and is used to increase the dietary fiber and micronutrient content of the product.

8. A vacuum tumbling processing method for low-salt, tender venison for group meals according to claim 1, characterized in that, The continuous rolling time in the first stage of step (3) is 15-25 minutes, and the total time of intermittent rolling in the second stage of step (5) is 25-35 minutes.

9. A vacuum tumbling processing method for low-salt, tender venison for group meals according to claim 1, characterized in that, The static marinating time in step (6) is 6 to 12 hours.

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