A low-temperature live-keeping and synergistic pretreatment method adaptable to multiple protein sources

Abstract

This invention relates to the field of food processing technology, providing a low-temperature preservation and synergistic pretreatment method adaptable to various protein sources. The method includes: subjecting the protein source raw material to hypertonic pretreatment, causing tissue fluid to migrate and precipitate off-odor substances; performing synergistic deodorization and activity regulation treatment at a temperature not exceeding 70°C; subsequently performing low-temperature enzyme inactivation and structural stabilization treatment, followed by sterilization using a low-temperature or heatless method; and finally processing it into a standardized intermediate suitable for food systems. This technical solution achieves effective removal of off-odors from protein sources at relatively low temperatures, while minimizing damage to protein structure and active ingredients, thus improving the nutritional retention and quality stability of the product. The method is applicable to animal-derived, plant-derived, and microbial-derived proteins, and can be widely used in various food systems, demonstrating good versatility and industrial application value.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a pretreatment method applicable to multiple types of protein sources. Specifically, it relates to a low-temperature preservation synergistic pretreatment method that takes into account both odor removal and active ingredient retention, as well as standardized protein source intermediates prepared by this method and their applications in food processing. Background Technology

[0002] With the development of the food industry and the increasing demand from consumers for high-protein and functional foods, diversified protein sources are gradually gaining attention. In addition to traditional livestock, poultry, aquatic, and dairy proteins, novel protein sources such as insect proteins, microbial proteins, and some plant proteins are gradually entering the food processing field due to their abundant resources, high nutritional value, and strong sustainability. However, protein raw materials from different sources still face a series of technical problems in practical applications, restricting their large-scale promotion and application.

[0003] In existing technologies, the pretreatment of protein sources typically includes steps such as washing, soaking, deodorization, and heat treatment. Among these, deodorization is a crucial step affecting the food application of protein sources. Especially for insect proteins, some aquatic proteins, and fermented proteins, which often contain volatile odor-causing substances such as amines and sulfides, traditional treatment methods often employ high-temperature heating, strong flavor masking, or single adsorption treatments for removal. However, while high-temperature treatment can reduce odor to some extent, it can easily lead to irreversible denaturation of the protein structure, resulting in nutrient loss and reduced functional activity; while single deodorization methods often suffer from unstable effectiveness or limited applicability, failing to meet the general treatment needs of various protein sources.

[0004] Furthermore, existing technologies often rely on high temperatures to achieve enzyme inactivation, shaping, and sterilization during processing. While this ensures product safety, it also damages the active substances in the protein source (such as enzymes, peptides, and other functional components), affecting the nutritional value and functional properties of the final product. For some bioactive protein sources, how to preserve their active ingredients as much as possible while ensuring safety has become a pressing technical problem to be solved.

[0005] On the other hand, different protein sources vary greatly in terms of tissue structure, water content, and flavor characteristics. Existing pretreatment processes are mostly designed for single raw materials and lack universal processing methods applicable to multiple protein sources. This results in poor process adaptability, complex production processes, and hinders industrial-scale promotion. At the same time, existing processing methods produce products with inconsistent forms after processing, making it difficult to form standardized intermediates, thus affecting their application stability and processing consistency in different food systems.

[0006] Therefore, how to provide a pretreatment method that can be adapted to multiple types of protein sources, effectively remove odors under relatively mild conditions, and at the same time take into account the stability of protein structure and the retention of active ingredients, and further obtain standardized intermediates with stable morphology and controllable quality, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a low-temperature preservation and synergistic pretreatment method that is adaptable to multiple types of protein sources, so as to solve the problems of unstable odor removal effect, easy loss of active ingredients due to high temperature dependence in the processing of multiple protein sources in the prior art, and poor processing adaptability, thereby achieving efficient deodorization, structural stability and functional activity preservation of protein sources under milder conditions.

[0008] To achieve the above objectives, the present invention provides the following technical solution: In one possible implementation, a low-temperature survival synergistic pretreatment method adaptable to multiple protein sources is characterized by comprising the following steps: S1. Hypertonic pretreatment step: The protein source raw material is placed in a food-grade hypertonic medium and treated at 20-35°C to cause the internal tissue fluid of the protein source to osmotically migrate and precipitate off-odor substances; the hypertonic medium is a solution system formed by sugars, salts, organic acids or combinations thereof; S2. Low-temperature synergistic deodorization and activity regulation step: Under conditions not exceeding 70°C, the protein source treated in step S1 is subjected to deodorization treatment, which includes one or more of physical deodorization, biological deodorization, adsorption and impurity removal, and natural flavor substance auxiliary treatment. S3. Low-temperature enzyme inactivation and structural stabilization step: The treated protein source is heat-treated at 60-70℃ to achieve enzyme inactivation and tissue structural stabilization; S4. Low-temperature or heatless sterilization step: The material obtained in step S3 is sterilized, wherein the sterilization method is selected from low-temperature pasteurization, ultra-high pressure treatment, low-dose irradiation treatment or a combination thereof; S5. Standardized processing steps: Process the sterilized protein source into standardized intermediates suitable for food systems.

[0009] In one possible implementation, the mass fraction of the solute in the hypertonic medium is 10% to 80%.

[0010] In one possible implementation, the hypertonic medium is selected from solutions of sucrose, glucose, honey, edible salt, lactic acid, or combinations thereof.

[0011] In one possible implementation, the physical deodorization includes at least one of adsorption, encapsulation, supercritical extraction, or thermal treatment; the biological deodorization includes at least one of enzymatic hydrolysis or microbial fermentation; and the adsorption removal includes activated carbon adsorption or porous material adsorption.

[0012] In one possible implementation, the low-temperature or heatless sterilization method is at least one of pasteurization, ultra-high pressure treatment at 100-600 MPa, or low-dose irradiation treatment at 1-10 kGy.

[0013] In one possible implementation, the protein source is at least one of animal-derived protein, plant-derived protein, or microbial-derived protein.

[0014] In one possible implementation, the animal-derived protein includes invertebrate protein or vertebrate protein.

[0015] In one possible implementation, the animal-derived protein is selected from earthworms, leeches, insect proteins, turtles, or combinations thereof.

[0016] In one possible implementation, a standardized protein source intermediate is characterized by being prepared by the method described in any of the above embodiments.

[0017] In one possible embodiment, a method for preparing a protein food is characterized by: adding the protein source intermediate described in the above embodiment to a food base, mixing, molding and post-processing to obtain the protein food, and using the by-products generated during the preparation process for fermentation, cultivation or as a process auxiliary medium after processing.

[0018] Based on the above technical solution, the low-temperature preservation and synergistic pretreatment method of the present invention, which is adaptable to multiple types of protein sources, achieves effective removal of odor substances and stable control of tissue structure of protein sources under low temperature conditions by sequentially performing hypertonic pretreatment, low-temperature synergistic deodorization and activity regulation, low-temperature enzyme inactivation and structural stabilization, low-temperature or heatless sterilization, and standardized processing on the protein sources. This solves the problems of unstable odor removal effect and easy loss of active ingredients in the processing of multiple types of protein sources.

[0019] Furthermore, the hypertonic pretreatment step creates an osmotic pressure difference inside the protein source, causing tissue fluid to migrate outward, thereby precipitating some soluble odor substances in advance, creating favorable conditions for subsequent deodorization treatment, reducing the intensity of subsequent treatment and improving the overall deodorization efficiency.

[0020] Furthermore, by performing synergistic deodorization and activity regulation treatment at a temperature not exceeding 70°C, physical deodorization, biological deodorization, and adsorption removal methods are combined and applied. This achieves odor removal while reducing the adverse effects of high temperature on protein structure and active ingredients, thereby achieving synergistic optimization of flavor improvement and functional preservation.

[0021] Furthermore, by setting up low-temperature enzyme inactivation and structural stabilization steps, the protein source can achieve enzyme inactivation and tissue fixation under relatively mild heat treatment conditions. This not only avoids the problem of excessive protein denaturation caused by high-temperature treatment, but also improves the structural stability and processing adaptability in subsequent processing.

[0022] Furthermore, by adopting low-temperature or heatless sterilization methods, the damage to protein nutrients and active substances caused by traditional high-temperature sterilization can be reduced while ensuring microbial safety, thereby improving the nutritional retention rate and quality stability of the product.

[0023] Furthermore, through standardized processing steps, the processed protein source is transformed into a stable intermediate with consistent quality, enabling it to adapt to different food systems and improving its versatility and controllability in various food processing processes.

[0024] Furthermore, the standardized protein source intermediates prepared by this invention can be widely used in various food systems. They can maintain good dispersibility, compatibility, and processing stability during the compounding process with food base materials. At the same time, by further processing and utilizing by-products, efficient recycling of resources can be achieved, improving the overall economic efficiency and environmental friendliness of the process.

[0025] In summary, this invention achieves a balance between deodorization efficiency, structural stability, and activity retention of protein sources through multi-step synergistic control, significantly enhancing the application value of various protein sources in the food industry. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall process flow of the low-temperature preservation and synergistic pretreatment method of the present invention, which is adaptable to multiple types of protein sources. The process includes, in sequence, a hypertonic pretreatment step, a low-temperature synergistic deodorization and activity regulation step, a low-temperature enzyme inactivation and structural stabilization step, a low-temperature or heatless sterilization step, and a standardized processing step. The steps are connected sequentially to form a complete processing flow. Detailed Implementation

[0027] To enable those skilled in the art to more clearly understand the technical concept, process logic, and implementation of this invention, the technical solution of this invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that this invention is not simply a matter of lowering the temperature or piecing together steps in existing protein source processing processes. Rather, it addresses the common problems encountered by various protein sources in food applications, such as strong off-flavors, structural instability, easy loss of active ingredients, and insufficient processing adaptability, by constructing an integrated processing system with sequential connections and synergistic mechanisms.

[0028] Specifically, this invention first utilizes a hypertonic pretreatment step to pre-migrate and pre-release off-odor substances and their precursor components within the protein source, reducing the load on subsequent processing. Then, through a low-temperature synergistic deodorization and activity regulation step, further removal of off-odors and adjustment of functional state are achieved under relatively mild conditions. Building on this, a low-temperature enzyme inactivation and structural stabilization step ensures the protein source achieves a stable tissue state suitable for subsequent processing. Next, a low-temperature or heatless sterilization step achieves safety control. Finally, standardized processing forms intermediate products suitable for different food systems. Thus, each step functionally divides its role and mutually supports each other in effect, jointly achieving a comprehensive improvement in the flavor, structure, safety, and application performance of the protein source.

[0029] The following is in conjunction with the appendix Figure 1 The technical solution of the present invention will be further described in detail below. It should be noted that the following embodiments are only used to explain the technical principles and inventive features of the present invention, and are not intended to limit the scope of protection of the present invention.

[0030] I. Overall Process Flow Description like Figure 1 As shown, the present invention provides a low-temperature preservation and synergistic pretreatment method adaptable to multiple protein sources. The method, in sequence, includes a hypertonic pretreatment step S1, a low-temperature synergistic deodorization and activity regulation step S2, a low-temperature enzyme inactivation and structural stabilization step S3, a low-temperature or heatless sterilization step S4, and a standardized processing step S5. These steps are sequentially connected in the process pathway and form a progressive synergistic regulatory system from beginning to end in terms of their mechanism of action.

[0031] Specifically, step S1, as a pre-treatment step, creates an external hyperosmolar environment to form an osmotic pressure difference between the inside and outside of the protein source, causing the water and soluble small molecules inside the protein source to migrate in a directional manner, thereby achieving the pre-release of odor substances and the initial adjustment of the tissue state, providing a favorable foundation for subsequent treatment.

[0032] Step S2 is performed based on step S1. Under controlled low-temperature conditions, residual odor substances are further removed through the synergistic effect of multiple deodorization mechanisms, including physical, biological, and adsorption mechanisms, while simultaneously regulating the structure and functional activity of the protein source. This step improves deodorization efficiency and reduces adverse effects on protein structure through the coupling of multiple pathway mechanisms.

[0033] Step S3, following step S2, involves heat-treating the protein source within a relatively mild temperature range to inactivate endogenous enzymes and stabilize the tissue structure. This step ensures the stability of the product during subsequent processing and storage while avoiding the excessive denaturation problems associated with traditional high-temperature treatments.

[0034] Step S4 is performed after structural stabilization. It involves using low-temperature or heatless sterilization to ensure the material meets microbiological requirements while minimizing the damage to protein nutrients and active substances caused by heat treatment. This step provides technical support for achieving a balance between product safety and quality maintenance.

[0035] Step S5, as the final processing step, transforms the protein source processed in the above steps into a standardized intermediate with uniform morphology and stable properties. By controlling particle size, morphology, and physical properties, the resulting intermediate can be adapted to the processing requirements of different food systems, improving its versatility and industrial controllability.

[0036] In summary, this invention organically integrates the various functional steps in a specific order, allowing the protein source to sequentially undergo the process of "odor substance migration - synergistic removal - structural stabilization - safety control - standardized output" during processing. The steps cooperate with each other and progress step by step, achieving synergistic optimization of the flavor, structure, and functional characteristics of the protein source as a whole, demonstrating significant systematicity and process synergy.

[0037] II. Implementation Methods of Hypertonic Pretreatment Steps In step S1, the protein source material is placed in a food-grade hypertonic medium for treatment. This step achieves active regulation of the internal microenvironment of the protein source by constructing an osmotic pressure difference between the inside and outside of the protein source. It is a key preliminary step for the present invention to achieve low-temperature and efficient deodorization and synergistic treatment.

[0038] Specifically, the hypertonic medium is a solution system formed by sugars, salts, organic acids, or combinations thereof, with a preferred solute mass fraction of 10% to 80%. By controlling the type and concentration of the solute, the system achieves a high osmotic pressure, thereby forming a stable osmotic gradient inside and outside the protein source tissue. Under the action of this osmotic gradient, water and soluble small molecules (including some volatile odor substances and their precursors) inside the protein source migrate outward, achieving the premature release of odor substances.

[0039] Preferably, when the hyperosmotic medium adopts a combination system of sugars and salts, osmotic pressure regulation and ionic strength adjustment can be achieved simultaneously, which is beneficial to breaking the binding state between some odor substances and proteins and improving their migration efficiency. When organic acid components are introduced, the pH value of the system can be adjusted to convert some alkaline odor substances (such as amines) into more soluble or more easily migrated forms, thereby further enhancing the deodorizing effect.

[0040] Furthermore, the processing temperature is controlled within the range of 20–35°C, so that the permeation process is carried out under relatively mild conditions. On the one hand, this ensures the efficiency of molecular migration, and on the other hand, it avoids protein structural denaturation or inactivation of active ingredients caused by high temperature, thus providing the prerequisite for the subsequent "low-temperature preservation" target.

[0041] During implementation, the hyperosmotic treatment time can be adjusted according to the type, structure, and particle size of the protein source to achieve a dynamic or near-equilibrium state in the osmosis process. For protein sources with dense structures, the treatment time can be appropriately extended or a segmented treatment method can be adopted to improve the osmosis effect; for protein sources with loose structures or small particles, the treatment time can be shortened to avoid excessive dehydration or flavor loss.

[0042] In addition, in some embodiments, gentle stirring or circulation can be incorporated into the hyperosmotic treatment process to enhance the external solution renewal rate, reduce local concentration polarization, and thus improve the overall permeation efficiency.

[0043] Compared to conventional soaking or washing methods in existing technologies, this invention creates a hypertonic environment that allows odor-causing substances within the protein source to "actively migrate" at low temperatures, rather than relying on subsequent high-temperature or harsh treatments for removal. This allows for pre-regulation of flavor at the forefront of the process. This osmosis-driven treatment method not only improves deodorization efficiency but also significantly reduces the intensity of subsequent treatments, providing a foundation for multi-step low-temperature synergistic processing and demonstrating outstanding technological advancement.

[0044] III. Low-Temperature Synergistic Deodorization and Activity Regulation Steps In step S2, the protein source treated in step S1 is subjected to low-temperature synergistic deodorization and activity regulation treatment at a temperature not exceeding 70°C. This step, based on the partial migration and release of odor substances achieved through hyperosmolar pretreatment, further removes residual odor substances through the synergistic coupling of multiple mechanisms, while simultaneously ensuring the integrity of the protein structure and the retention of active ingredients. This is the core link in achieving the goal of "low-temperature, high-efficiency deodorization and functional preservation" in this invention.

[0045] Specifically, the deodorization treatment includes one or more of the following: physical deodorization, biological deodorization, adsorption and impurity removal, and auxiliary treatment with natural flavor substances. These various treatment methods complement each other in their mechanisms of action: physical deodorization mainly removes volatile or semi-volatile odor molecules through adsorption, encapsulation, or extraction; biological deodorization converts odor-causing precursors into low-odor or odorless small molecules through enzymatic hydrolysis or microbial metabolism; adsorption and impurity removal further removes impurities and residual odor components from the system; and natural flavor substances improve the overall sensory quality through odor masking and flavor harmonization.

[0046] Preferably, the above-mentioned deodorization methods are implemented in combination of two or more to achieve a synergistic effect. For example, during enzymatic hydrolysis, specific enzyme preparations are used to selectively decompose proteins or lipids, degrading some odor precursors, while adsorption materials capture the released odor molecules, thereby improving the overall deodorization efficiency; or the metabolites produced during fermentation work synergistically with natural flavor substances to achieve odor transformation and reconstruction.

[0047] Regarding temperature control, this step is limited to a temperature not exceeding 70℃, preferably within the range of 30–65℃. Compared to traditional high-temperature deodorization processes, this temperature range ensures the effective execution of some reaction processes (such as enzymatic reactions or microbial metabolism) while avoiding drastic protein denaturation, thus helping to maintain the protein's native conformation and functional properties.

[0048] Furthermore, in some implementations, a balance can be achieved between deodorization and activity maintenance by controlling parameters such as processing time, pH value, and system water activity. For example, the amount of enzyme and reaction time can be controlled during enzymatic hydrolysis to avoid excessive hydrolysis leading to a decline in taste; the fermentation endpoint can be controlled during fermentation to prevent the formation of new undesirable flavors.

[0049] Furthermore, since step S1 has already reduced the initial content of odor substances in the protein source, the processing intensity required in this step is relatively lower, thus allowing for deep deodorization under gentler conditions. This synergistic strategy of "pretreatment to reduce load + post-treatment to finely control" makes the overall process both efficient and gentle.

[0050] Compared to existing technologies that rely on a single deodorization method or high-temperature intensification treatment, this invention achieves graded removal and transformation of odor substances under low-temperature conditions through the synergistic effect of multiple mechanisms, while protecting protein structures and active ingredients, forming an integrated treatment path of "deodorization-regulation-preservation". This significantly improves the stability and applicability of the treatment effect, demonstrating outstanding technological progress.

[0051] IV. Low-temperature enzyme inactivation and structural stabilization steps In step S3, the protein source treated in step S2 is subjected to low-temperature heat treatment at 60–70°C to inactivate endogenous enzymes and stabilize the tissue structure. This step plays a crucial role in the overall process of this invention, terminating enzymatic reactions that may continue to occur during the preceding treatment and appropriately regulating the microstructure of the protein source to provide a stable foundation for subsequent sterilization and processing.

[0052] Specifically, protein sources typically contain various endogenous enzymes, such as proteases, lipases, and oxidases. Under certain conditions, these enzymes may cause problems such as protein degradation, lipid oxidation, or flavor deterioration. By controlling the processing temperature within the range of 60–70°C, these enzymes can be effectively inactivated under relatively mild conditions, thereby preventing quality degradation during subsequent processing and storage.

[0053] Meanwhile, within this temperature range, protein molecules undergo limited conformational changes, transforming from their original native structure to a more stable spatial structure. This process facilitates the formation of a uniform and stable tissue state, improving the structural integrity and processing adaptability of the protein source in subsequent processing. For example, after appropriate heat treatment, the water-holding capacity, adhesion, and dispersibility of the protein source can be improved, which is beneficial for its application in different food systems.

[0054] Preferably, by controlling the heating time and rate of increase, the protein denaturation process is kept within a controllable range, thereby avoiding textural hardening, nutrient loss, or flavor deterioration caused by overheating. In some embodiments, staged heating or constant temperature maintenance can be used to gradually stabilize the protein structure and improve processing uniformity.

[0055] Furthermore, since the present invention has significantly reduced the content of odor substances and adjusted the system state through hyperosmotic pretreatment and low-temperature synergistic deodorization in the preceding steps, this step does not require the use of traditional high-temperature blanching (such as above 90°C) to achieve the desired enzyme inactivation and shaping effects. This technical approach, which achieves functionally equivalent or even better effects at a lower temperature, demonstrates the advantages of the present invention in process synergistic design.

[0056] Compared to the high-temperature rapid processing methods commonly used in existing technologies, this invention, by precisely controlling the temperature range, enables the enzyme inactivation and structural stabilization processes to be completed under mild conditions. This not only reduces the damage to protein nutrients and active substances but also improves the stability and consistency of product quality, thereby achieving a synergistic balance between "structural stability" and "functional retention," demonstrating significant technological advancement.

[0057] V. Low-temperature or heatless sterilization steps In step S4, the protein source treated in step S3 is subjected to low-temperature or heatless sterilization to ensure the product's microbiological safety while minimizing adverse effects on the protein structure and active ingredients. This step, by employing a gentler treatment method that differs from traditional high-temperature sterilization, achieves a synergistic balance between "safety and quality maintenance" and is an important component of the low-temperature process system of this invention.

[0058] Specifically, the sterilization method is selected from low-temperature pasteurization, ultra-high pressure treatment, low-dose irradiation treatment, or a combination thereof. Ultra-high pressure treatment, by applying pressure of 100–600 MPa to the material, destroys the microbial cell structure, thereby achieving sterilization. Low-dose irradiation treatment, through ionizing radiation, destroys the genetic material of microorganisms, achieving effective control of microorganisms. In some embodiments, a single method or a combination of methods can be selected according to the characteristics of the protein source and the requirements of the target product to obtain better sterilization and quality preservation effects.

[0059] Preferably, when using low-temperature pasteurization, the temperature and time parameters are controlled to inhibit or kill the target microorganisms under relatively mild conditions; when using ultra-high pressure or irradiation treatment, the sterilization effect and protein quality can be balanced by adjusting the treatment intensity and the treatment time.

[0060] Furthermore, since steps S1 to S3 have pretreated the protein source and significantly reduced the microbial load and system instability factors, the sterilization intensity required in this step can be reduced accordingly, thereby avoiding the severe damage to protein structure, nutrients, and active substances caused by traditional high-temperature sterilization. This design, based on the synergistic reduction of sterilization intensity in the preceding and following processes, helps to improve product quality while ensuring safety.

[0061] In addition, low-temperature or heatless sterilization methods can effectively reduce flavor deterioration and color changes caused by high-temperature processing, which helps to maintain the original sensory characteristics of the protein source and improve the market acceptance of the final product.

[0062] Compared to the high-temperature sterilization methods commonly used in existing technologies, this invention introduces low-temperature or heatless sterilization methods and forms a synergistic system with the preceding low-temperature treatment steps. This significantly reduces heat damage while ensuring microbial safety, and effectively protects the nutritional value and functional activity of proteins, thus demonstrating outstanding technological progress.

[0063] VI. Standardized Processing Steps In step S5, the protein source processed in steps S1 to S4 is standardized to transform it into intermediate products suitable for different food systems. This step, through unified control of the protein source's morphology, particle size, and physical properties, achieves product standardization and reproducibility, and is a crucial step in realizing the industrial application of this invention.

[0064] Specifically, the standardized processing includes crushing, homogenizing, grading, concentrating, or drying the protein source to form an intermediate with a stable morphology, including but not limited to minced meat, protein slurry, protein liquid, fine particles, or protein powder. By controlling processing parameters, the resulting intermediate meets preset standards in terms of particle size distribution, moisture content, and rheological properties, thereby satisfying the requirements of different food processing techniques.

[0065] Preferably, the particle size is controlled by homogenization during processing to make the protein source reach a fine state, thereby improving its dispersibility and uniformity in food base materials; when drying is required, spray drying, freeze drying or vacuum drying can be used to obtain stable powder products and extend their storage period.

[0066] Furthermore, by regulating the physical properties of standardized intermediates, they can be made to have good processing adaptability, such as suitable viscosity, water retention and flowability, so as to be compatible with different types of food systems, including but not limited to gel foods, dairy products, beverages and functional foods.

[0067] Furthermore, since the preceding steps have effectively removed off-flavor substances and stabilized the protein structure, the intermediates obtained in this step have high consistency in terms of flavor, structure, and functional properties, which can significantly improve the stability and controllability of product quality in subsequent food processing.

[0068] Compared to existing technologies that process protein raw materials directly or produce materials in inconsistent forms, this invention introduces standardized processing steps to transform the protein source from a "raw material state" to a "functionalized intermediate state." This not only enhances its versatility in different food systems but also improves consistency and efficiency in industrial production, thus demonstrating significant technological advancement.

[0069] VII. Synergistic Effects and Overall Technical Results This invention organically integrates a hypertonic pretreatment step S1, a low-temperature synergistic deodorization and activity regulation step S2, a low-temperature enzyme inactivation and structural stabilization step S3, a low-temperature or heatless sterilization step S4, and a standardized processing step S5, constructing a multi-stage, multi-mechanism synergistic protein source pretreatment process system. The steps are not only sequentially connected in the process flow, but also mutually cooperate and reinforce each other in their mechanisms of action, thus forming an overall synergistic effect.

[0070] Specifically, at the front end of the process, an osmotic pressure gradient is established through a high-osmotic pretreatment step S1 to achieve the pre-migration and release of odor substances inside the protein source, reducing the odor load in the system from the source. In the intermediate stage, through a low-temperature synergistic deodorization and activity regulation step S2, the residual odor substances are further removed by utilizing the synergistic effect of multiple deodorization mechanisms, and the protein structure and functional state are finely regulated. Subsequently, through a low-temperature enzyme inactivation and structural stabilization step S3, enzyme inactivation and tissue structure fixation are achieved under mild conditions, giving the protein source a stable physical structure and processing performance. On this basis, through a low-temperature or heatless sterilization step S4, microbial safety control is achieved while reducing heat damage. Finally, through a standardized processing step S5, the treated protein source is transformed into an intermediate product with uniform morphology and stable performance.

[0071] The above steps form a collaborative processing mechanism of "front-end burden reduction - mid-stage precision control - back-end stability": the front end reduces the difficulty of subsequent processing through penetration drive, the mid-stage achieves efficient deodorization and activity regulation through multi-mechanism coupling, and the back end achieves structural stability and safety assurance through mild conditions, thereby avoiding the problems of severe protein denaturation, large activity loss and unstable flavor caused by relying on high temperature or single processing methods in existing technologies.

[0072] Through this multi-step synergistic system, the present invention can simultaneously achieve the following technical effects under relatively low temperature conditions: first, it significantly improves the deodorization efficiency and stability of various protein sources; second, it effectively maintains the structural integrity and functional activity of protein sources; third, it enhances the dispersibility, compatibility, and processing adaptability of protein sources in subsequent food processing; and fourth, it achieves the standardization and controllability of intermediate products, thereby improving the consistency and efficiency of industrial production.

[0073] In summary, this invention, by constructing an overall process system dominated by low temperature and synergistic with multiple mechanisms, achieves comprehensive improvement in flavor, structure, and function while ensuring food safety. It significantly expands the application scope of various protein sources in the food field, demonstrating outstanding technological progress and practical application value.

[0074] VIII. Specific Application Examples and Comparative Examples To further illustrate the practical application effects of the technical solution of the present invention, the present invention will be described below in conjunction with specific embodiments and comparative examples. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Specific conditions not specified in the embodiments are generally performed according to conventional conditions in the art; raw materials and reagents not specified are all commercially available food-grade or laboratory-grade products.

[0075] (I) Testing Items and Evaluation Methods To evaluate the processing effect of the method of the present invention, the samples obtained in each embodiment and comparative example were subjected to the following tests: 1. Sensory evaluation of fishy smell: The evaluation is conducted by 10 trained evaluators, with a maximum score of 10 points. The higher the score, the more pronounced the fishy smell.

[0076] 2. Protein activity retention rate: The percentage of the target active ingredient or enzyme activity retained after treatment is calculated based on the content of the target active ingredient or enzyme activity in the protein source before treatment.

[0077] 3. Total bacterial count: determined according to standard methods for food microbiological testing.

[0078] 4. Dispersion stability: Add the obtained intermediate to soy milk or milk base in a certain proportion, observe the stratification and sedimentation after standing for 30 minutes, and record the stability.

[0079] 5. Product acceptability evaluation: A comprehensive evaluation is conducted based on the color, taste, and flavor harmony of the final product.

[0080] It should be noted that the "active ingredients" mentioned in this invention mainly refer to the components in the protein source that have biological or nutritional functions, including but not limited to enzyme active ingredients (such as proteases, antioxidant enzymes, etc.), bioactive peptides, functional proteins, or other active substances with specific physiological functions.

[0081] The "activity retention rate" described in this invention is used to characterize the degree to which the above-mentioned active ingredients are retained during the treatment process. It can be calculated by measuring the content or activity value of the target active ingredient before and after treatment. Specifically, the activity retention rate can be calculated as follows: Activity retention rate (%) = (content or activity value of target active ingredient in the treated sample ÷ corresponding index value in the sample before treatment) × 100%.

[0082] The detection method for the target active ingredient can adopt conventional detection methods in the field according to its type. For example, enzyme activity can be determined by spectrophotometry, and peptide content can be determined by high performance liquid chromatography (HPLC) or relevant standard methods.

[0083] Example 1: Preparation of standardized intermediates for earthworm protein Fresh earthworms were selected as the protein source, and after washing and draining, they were ready for use.

[0084] S1. High-osmotic pretreatment: The earthworms were treated in a hypertonic medium, which was a composite solution consisting of 20% sucrose, 5% edible salt and 1% lactic acid by mass. The treatment temperature was 25°C, the treatment time was 40 minutes, and the material-to-liquid ratio was 1:3.

[0085] S2. Low-temperature synergistic deodorization and activity regulation: After the earthworms were treated with hypertonic solution, they were drained and then 0.15% papain was added. The mixture was enzymatically hydrolyzed at 45°C for 20 minutes. Subsequently, 2% β-cyclodextrin and 0.5% ginger extract were added, and the mixture was further treated at 50°C for 15 minutes.

[0086] S3. Low-temperature enzyme inactivation and structural stability: Heat the material processed in step S2 to 65°C and maintain the temperature for 8 minutes.

[0087] S4. Low-temperature or heatless sterilization: The material obtained in step S3 is subjected to ultra-high pressure treatment at 300MPa for 10 minutes.

[0088] S5. Standardized processing: The sterilized material was processed by a colloid mill, and the particle size D90 was controlled to be no greater than 0.8 mm to obtain a standardized intermediate of earthworm protein.

[0089] The intermediate was tested and found to have a fishy smell score of 2.3, a target active ingredient retention rate of 82%, and a total bacterial count that met the requirements for food processing intermediates. It was also found to be evenly dispersed in the soy milk system with no obvious sedimentation.

[0090] Example 2: Preparation of black soldier fly protein standardization intermediate Artificially bred black soldier fly larvae were selected as the protein source material, and were cleaned and used for later use.

[0091] S1. High-osmotic pretreatment: Black soldier fly larvae were placed in a hypertonic medium consisting of 15% glucose, 4% edible salt and 0.8% lactic acid by mass and treated at 30°C for 30 minutes with a material-to-liquid ratio of 1:4.

[0092] S2. Low-temperature synergistic deodorization and activity regulation: The treated black soldier fly larvae were added to 1.5% activated carbon and 0.3% rosemary extract and treated at 55°C for 25 minutes; then the adsorption material was separated.

[0093] S3. Low-temperature enzyme inactivation and structural stability: The treated material was kept at 68°C for 6 minutes.

[0094] S4. Low-temperature or heatless sterilization: Low-dose irradiation treatment of 5 kGy was used.

[0095] S5. Standardized processing: A standardized intermediate of black soldier fly protein powder was obtained by homogenization and spray drying.

[0096] The test results showed that the intermediate had a fishy smell score of 2.8, a protein activity retention rate of 76%, and good powder dispersibility, and could be stably dispersed in the emulsion base.

[0097] Example 3: Application of Ganoderma lucidum mycelium protein intermediates and yogurt Ganoderma lucidum mycelium was selected as the raw material for microbial protein.

[0098] S1. High-osmotic pretreatment: Ganoderma lucidum mycelium was placed in a hypertonic medium consisting of 25% honey and 2% edible salt by mass and treated at 22°C for 35 minutes.

[0099] S2. Low-temperature synergistic deodorization and activity regulation: Add 0.1% of the complex protease and treat at 42℃ for 15 minutes; then add 1% of the porous adsorption material and 0.4% of the onion extract and treat at 45℃ for 20 minutes.

[0100] S3. Low-temperature enzyme inactivation and structural stability: Treat at 62℃ for 10 minutes.

[0101] S4. Low-temperature or heatless sterilization: It is treated with an ultra-high pressure of 400MPa for 8 minutes.

[0102] S5. Standardized processing: Ganoderma lucidum mycelium protein paste intermediate was obtained by wet grinding and homogenization.

[0103] The intermediate was added to cow's milk at 8% of the total mass of the milk base, and after homogenization, inoculation with a starter culture, and fermentation at 37°C to pH 4.5, protein-based yogurt was obtained. The resulting yogurt had a mild flavor, no obvious mycelial off-flavor, a homogeneous and stable system, and high overall acceptability.

[0104] Comparative Example 1: No hypertonic pretreatment was used; only subsequent deodorization treatment was performed. Using the same earthworm raw material as in Example 1, without performing the high-osmotic pretreatment in step S1, the process was directly carried out with enzymatic hydrolysis, cyclodextrin treatment, low-temperature enzyme inactivation, ultra-high pressure treatment, and standardized processing, with the remaining conditions being the same as in Example 1.

[0105] The test results showed that the intermediate had a fishy smell score of 4.9, significantly higher than that of Example 1; the protein activity retention rate was 81%, similar to that of Example 1, but the flavor improvement effect was significantly worse. This indicates that the high-osmotic pretreatment step can effectively reduce the initial odor load of the raw materials and improve the overall deodorization effect.

[0106] Comparative Example 2: Using traditional high-temperature blanching and deodorization process Using the same earthworm raw material as in Example 1, the earthworm was first blanched in hot water at 95°C for 5 minutes, then soaked in ginger juice for 15 minutes, and then pulverized by a colloid mill to obtain an intermediate. The low-temperature synergistic and mild sterilization processes in steps S1, S2 and S4 of this invention were not performed.

[0107] The test results showed that the sample scored 3.8 points for fishy odor, with a protein activity retention rate of only 52%, and the system exhibited a noticeable grainy texture after being added to soy milk. This indicates that while traditional high-temperature treatment can improve the fishy odor to some extent, it significantly damages the active ingredients and their structural state, which is detrimental to subsequent food applications.

[0108] Comparative Example 3: Deodorization treatment using only single adsorption method Using the same black soldier fly larvae as in Example 2, without high-osmotic pretreatment or enzymatic hydrolysis or natural flavoring agent treatment, only 2% activated carbon was added and treated at 55°C for 25 minutes. The remaining steps were the same as in Example 2.

[0109] The test results showed that the fishy smell score of the obtained sample was 4.2 points and the protein activity retention rate was 74%, indicating that although a single adsorption method can reduce the odor to a certain extent, the overall effect is not as good as the multi-mechanism synergistic deodorization method described in this invention.

[0110] (II) Comparison of the effects of the examples and comparative examples From the combined examples 1-3 and comparative examples 1-3, it can be seen that: 1. This invention, by setting a high-osmotic pretreatment step at the front end, can promote the pre-migration of odor substances and their precursors inside the protein source, thereby reducing the subsequent deodorization load and improving the overall deodorization efficiency.

[0111] 2. This invention employs a low-temperature synergistic deodorization and activity regulation method, which enables physical deodorization, biological deodorization, adsorption and impurity removal, and natural flavor auxiliary treatment to work synergistically, achieving both odor control and functional preservation at a relatively low temperature.

[0112] 3. The present invention employs low-temperature enzyme inactivation and low-temperature or heatless sterilization steps, which are more conducive to maintaining the active ingredients, structural state, and subsequent processing adaptability of the protein source compared with traditional high-temperature blanching or high-temperature sterilization processes.

[0113] 4. The standardized protein source intermediates prepared by the method of this invention have good dispersibility, stability and flavor harmony in food systems such as soy milk and milk base, demonstrating good practical application value.

[0114] Table 1. Comparison of processing effects between different embodiments and comparative examples Table 2 Evaluation of the application effects of standardized protein intermediates in food systems As shown in Tables 1 and 2, the method of the present invention is superior to the comparative example in terms of odor control, active ingredient retention, and system stability. Specifically, the combination of high-osmotic pretreatment and low-temperature synergistic deodorization significantly reduced the odor score; the low-temperature treatment system effectively improved the retention rate of active ingredients; and the obtained standardized intermediates exhibited good dispersibility and processing adaptability in different food systems, verifying the effectiveness and superiority of the technical solution of the present invention.

[0115] (III) Statistical significance analysis and effect description To further verify the superiority of the technical solution of the present invention, statistical analysis was performed on the data obtained from the examples and comparative examples. The fishy smell score, activity retention rate and comprehensive sensory score were all expressed as the average of the results of three parallel tests, and the significance was tested using conventional statistical methods (significance level α=0.05).

[0116] The analysis results show that: 1. Regarding the fishy smell score, the scores of Examples 1 to 3 were significantly lower than those of Comparative Examples 1 to 3 (P < 0.05), indicating that the present invention, through the combination of hyperosmotic pretreatment and low-temperature synergistic deodorization, can effectively reduce the content of odorous substances in protein sources, and its deodorization effect has a statistically significant advantage.

[0117] 2. Regarding the activity retention rate, Examples 1-3 were significantly higher than Comparative Example 2, which was treated with high temperature (P<0.05), indicating that the present invention can effectively reduce protein structure damage and loss of active ingredients through low-temperature enzyme inactivation and low-temperature or heatless sterilization processes, thereby achieving significant protection of functional components.

[0118] 3. In terms of dispersion stability and application effect, the dispersion and stability of the sample in tofu, dairy products and other systems are significantly better than those of the comparative sample, and the overall score is significantly improved (P<0.05), indicating that the protein source intermediate treated by the method of the present invention has better processing adaptability and product consistency in food systems.

[0119] 4. Compared with the example, Comparative Example 1 (without hyperosmotic pretreatment) showed a significant difference in odor score (P < 0.05), indicating that the hyperosmotic pretreatment step plays a key role in reducing the initial odor load and is an important factor in improving the overall deodorization effect.

[0120] 5. Compared with the Example, Comparative Example 3 (using only single adsorption for deodorization) showed significant differences in both odor control and overall score (P < 0.05), indicating that the present invention employs a multi-mechanism synergistic deodorization method, which has a better technical effect than a single treatment method.

[0121] In summary, statistical analysis confirms that the present invention has achieved significant improvements over existing technologies in terms of odor control, activity retention, and application performance. The related technical effects have clear statistical significance, thereby further verifying the effectiveness and advancement of the technical solution of the present invention.

[0122] The above results indicate that there is a synergistic effect among the steps described in this invention, and its technical effect is not a simple superposition of individual technical means, but rather produces a comprehensive effect that is significantly better than the prior art.

[0123] The technical solution of the present invention has been described in detail above with reference to the accompanying drawings and specific embodiments. The present invention achieves efficient deodorization, structural stabilization, and retention of active ingredients in various protein sources under low-temperature conditions by constructing a multi-step synergistic system encompassing hyperosmolar pretreatment, low-temperature synergistic deodorization, low-temperature enzyme inactivation and structural stabilization, low-temperature or heatless sterilization, and standardized processing. This significantly improves the application performance and industrial adaptability of protein sources in food processing. The above embodiments further verify the comprehensive advantages of the present invention in odor control, activity retention, and product stability, demonstrating that the present invention has good practical application value.

[0124] It should be noted that this invention is not limited to the specific embodiments described above. For those skilled in the art, various modifications, substitutions, or equivalent transformations can be made to the technical solutions of this invention without departing from its spirit and essence, and all such modifications, substitutions, or equivalent transformations should fall within the protection scope of this invention. The protection scope of this invention is defined by the appended claims.

Claims

1. A low-temperature preservation and synergistic pretreatment method adaptable to multiple protein sources, characterized in that, Includes the following steps: S1. High-infiltration pretreatment steps: The protein source material is placed in a food-grade hypertonic medium and treated at 20–35°C to cause the internal tissue fluid of the protein source to osmotically migrate and precipitate off-odor substances; the hypertonic medium is a solution system formed by sugars, salts, organic acids or combinations thereof. S2. Low-temperature synergistic deodorization and activity regulation steps: Under conditions not exceeding 70°C, the protein source treated in step S1 is subjected to deodorization treatment, which includes one or more of physical deodorization, biological deodorization, adsorption and impurity removal, and natural flavor substance auxiliary treatment. S3. Low-temperature enzyme inactivation and structural stabilization steps: The treated protein source was heat-treated at 60–70°C to achieve enzyme inactivation and tissue structure stabilization. S4. Low-temperature or heatless sterilization procedure: The material obtained in step S3 is sterilized, and the sterilization method is selected from low-temperature pasteurization, ultra-high pressure treatment, low-dose irradiation treatment or a combination thereof. S5. Standardized processing steps: The sterilized protein source is processed into standardized intermediates suitable for food systems.

2. The method according to claim 1, characterized in that: The mass fraction of the solute in the hypertonic medium is 10% to 80%.

3. The method according to claim 1, characterized in that: The hypertonic medium is selected from solutions of sucrose, glucose, honey, edible salt, lactic acid, or combinations thereof.

4. The method according to claim 1, characterized in that: The physical deodorization includes at least one of adsorption, encapsulation, supercritical extraction or heat treatment; The biological deodorization includes at least one of enzymatic hydrolysis or microbial fermentation; The adsorption and impurity removal includes activated carbon adsorption or porous material adsorption.

5. The method according to claim 1, characterized in that: The low-temperature or heatless sterilization method is as follows: At least one of pasteurization, ultra-high pressure treatment at 100–600 MPa, or low-dose irradiation treatment at 1–10 kGy.

6. The method according to claim 1, characterized in that: The protein source is at least one of animal-derived protein, plant-derived protein, or microbial-derived protein.

7. The method according to claim 6, characterized in that: The animal-derived proteins include invertebrate proteins or vertebrate proteins.

8. The method according to claim 6 or 7, characterized in that: The animal-derived protein is selected from earthworms, leeches, insect proteins, turtles, or combinations thereof.

9. A standardized protein source intermediate, characterized in that: It is prepared by the method described in any one of claims 1 to 8.

10. A method for preparing a protein food, characterized in that: The protein source intermediate described in claim 9 is added to a food base, and the resulting food product is prepared through mixing, molding, and post-processing. The byproducts generated during the preparation process are processed and used for fermentation, cultivation, or as process auxiliary media.

Images