Method for co-production of mulberry fruit and anthocyanins based on mild extraction and anthocyanin stabilization

Abstract

This invention discloses a method for the co-production and processing of mulberries based on mild boiling extraction and anthocyanin stabilization protection, belonging to the field of food processing technology. Addressing the technical problems in traditional mulberry processing, such as significant degradation of heat-sensitive components like anthocyanins and loss of flavor substances due to excessive heat or prolonged heating, and the easily broken fruit pomace affecting the clarity of juice and the integrity of dried fruit, this invention employs the following approach: whole, fresh mulberries are subjected to short-term high-temperature saturated steam treatment to alter epidermal cell permeability and achieve preliminary sterilization; followed by programmed cooling to rapidly remove them from the high-temperature destructive zone; and then held at a medium temperature of 65-75℃ to promote juice exudation. Solid-liquid separation is then performed to obtain clarified mulberry juice and intact mulberry pomace. Finally, the juice is sterilized and bottled, and the pomace is dried to obtain dried mulberries. This method is mainly used for the simultaneous production of high-nutritional-value, high-flavor mulberry juice and plump dried mulberries, achieving efficient co-production and processing of mulberries.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a method for the co-production and processing of mulberry fruit based on mild boiling extraction and anthocyanin stabilization protection. Background Technology

[0002] Mulberries are rich in heat-sensitive nutrients such as anthocyanins, and their processing traditionally involves heating to extract juice or prepare dried fruit. Conventional processing methods typically employ high temperatures or long heating times for extraction to maximize juice yield. However, this relatively intense heat processing method easily leads to significant degradation of heat-sensitive components like anthocyanins in mulberries, resulting in a decline in the nutritional value and color stability of the juice. Simultaneously, the high heat load can also damage the flavor compounds of mulberries, causing a deterioration in the product's flavor. In pursuing high juice extraction rates, the applied heat during processing is often difficult to control precisely, and the pulp is easily subjected to severe morphological damage due to heat softening and subsequent mechanical separation, resulting in pulp fragments mixed into the juice, affecting clarity. Furthermore, the broken pulp is difficult to use directly in the production of intact dried fruit products. Attempts to lower the temperature or shorten the processing time to protect nutrients often result in insufficient extraction efficiency, low juice yield, and incomplete sterilization or enzyme inactivation due to insufficient heat treatment. Finding a balance between effectively obtaining juice and maintaining the shape of the pomace, while maximizing the retention of heat-sensitive nutrients, has been a long-standing technical challenge in mulberry processing. Summary of the Invention

[0003] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0004] Another objective of this invention is to provide a mulberry co-processing method based on mild boiling extraction and anthocyanin stabilization protection, which can significantly reduce the loss of heat-sensitive flavor components and the degradation rate of anthocyanins during processing while obtaining clear mulberry juice and morphologically intact mulberry wet residue.

[0005] To achieve these objectives and other advantages of the present invention, a method for the co-production and processing of mulberry fruit based on mild boiling extraction and anthocyanin stabilization protection is provided, comprising the following steps: S1: Place whole, fresh mulberries in a processing device, introduce saturated steam at 105-115 ℃, and process for 60-120 seconds; The processing device includes an inner liner and an outer liner. The bottom of the inner liner is provided with an inner liner drain port and the top is provided with a steam inlet. The inner liner is fitted inside the outer liner, and the bottom of the inner liner and the bottom of the outer liner form a liquid collection chamber. The bottom of the outer liner is provided with an outer liner drain port. An external saturated steam pipe passes through the outer liner and is connected to the steam inlet. S2: Perform a programmed cooling process on the mulberries after step S1, reducing their overall temperature to 65-75℃ within 3-8 minutes, and then maintaining the temperature within the range of 65-75℃ for another 20-40 minutes. S3: Separate the solid and liquid components of the mulberry fruit after the heat preservation in step S2 to obtain clear mulberry juice and intact mulberry fruit wet residue. S4: Sterilize and fill the mulberry juice, and dry the wet mulberry residue to obtain dried mulberry.

[0006] Traditional mulberry processing methods often face challenges in the co-production of juice and pomace, leading to significant degradation of heat-sensitive components such as anthocyanins and loss of flavor substances due to intense or prolonged heat treatment. Simultaneously, the pomace is prone to breakage due to heat softening and mechanical separation, affecting the clarity of the juice and the shape of the dried fruit. To address these challenges, this invention first employs a very short-duration high-temperature saturated steam treatment to rapidly alter the permeability of mulberry epidermal cells and achieve preliminary sterilization. Immediately following, a precisely controlled programmed cooling process is implemented, quickly removing the material temperature from the high-temperature destructive range and stabilizing it within a medium temperature range of 65-75°C. This series of steps keeps the heat load of the entire extraction process at a low level, promoting effective juice extraction while minimizing the damage to heat-sensitive components caused by sustained high temperatures. Thanks to this gentle and controlled heat treatment method, not only is clear mulberry juice obtained, but the morphology of the wet mulberry pomace is also preserved, providing a good foundation for subsequent processing into juice and dried fruit products. This achieves effective preservation of the juice flavor, nutritional value, and pomace morphology during the co-production process.

[0007] Preferably, before performing the programmed cooling in step S2, a food-grade inert gas, namely nitrogen or carbon dioxide, is continuously introduced into the mixture of mulberry fruit and mulberry juice treated in step S1 for 5-15 minutes.

[0008] In mulberry processing based on mild boiling and extraction, although the material temperature is rapidly reduced to 65-75℃ and held at this temperature to minimize heat damage, residual oxygen and trace amounts of oxidase activity in this intermediate temperature stage can still cause slow oxidation of anthocyanins and flavor components, affecting the color and nutritional value of the final product. Therefore, before cooling begins, food-grade nitrogen or carbon dioxide is continuously introduced into the mulberry and juice mixture. This inert gas replaces and removes internal oxygen, creating a low-oxygen or anaerobic insulated environment. This method physically isolates oxygen contact, effectively inhibiting oxidation reactions. Thus, without relying on exogenous chemical additives, it further reduces the degradation of heat-sensitive and easily oxidized substances, helping to better maintain the natural flavor of the juice and the stability of anthocyanins.

[0009] Preferably, in step S3, the solid-liquid separation of the mixture after the heat preservation treatment in step S2 is achieved in the following manner: After the heat preservation treatment in step S2, at least 60% of the volume of mulberry juice is discharged through the drain port of the inner tank to obtain the primary clarified liquid. The mulberry pulp residue at the bottom of the inner liner, along with the remaining mixture, is transferred to a horizontally positioned drain conveyor belt equipped with a vibrating screen. The vibrating screen has an aperture of 2-4 mm, a vibration frequency of 10-15 Hz, and an amplitude of 2-5 mm. During the vibrating conveying process, multiple low-pressure, wide-width fan-shaped airflow nozzles arranged above the drain conveyor belt continuously blow the mulberry pulp residue layer on the conveyor belt at a wind speed of 0.5-1.0 m / s and a temperature of 25-35 ℃. The liquid drained through the vibrating screen is collected and combined with the primary clarified liquid. It is then filtered through a static tubular filter with a pore size of 100-150 micrometers to obtain clarified mulberry juice. The material after blowing and draining is the mulberry wet residue with intact shape.

[0010] After gentle boiling and extraction, the mulberry pulp retains its basic shape but its structure becomes loose. During subsequent solid-liquid separation, conventional pressing or centrifugation methods can easily cause the pulp to deform or even break due to mechanical pressure or its own weight, resulting in pulp fragments mixing into the juice and affecting the final clarity. To solve this separation problem, this invention employs a step-by-step physical separation strategy: First, at least 60% of the mulberry juice is discharged through the inner tank drain, thus removing most of the juice without external force and significantly reducing the static pressure of the liquid on the pulp in subsequent steps. Then, the remaining mixture is transferred to a horizontally positioned vibrating screen conveyor belt, where gentle vibration with specific parameters promotes solid-liquid separation while avoiding crushing or shearing of the pulp. During this process, a low-pressure, wide-width fan-shaped airflow continuously blows through the pulp layer. This airflow not only removes the surface water film to enhance drainage but also generates a slight lifting force that partially counteracts the pile pressure of the pulp itself and the upper layer, creating dynamic air gaps between the pulp particles and effectively preventing mutual compression and adhesion. By combining gravity-based initial separation, gentle mechanical draining, and dynamic airflow assistance, the clarified juice can be efficiently separated while ensuring the integrity of the mulberry pulp, laying the foundation for obtaining high-quality juice and intact pulp for drying.

[0011] Preferably, after the mulberry fruit residue with intact shape is obtained through blowing and draining, and before drying, a pretreatment of surface slow-release drying and microporous structure maintenance is included in the mulberry fruit residue, specifically: The wet mulberry residue is evenly spread on the mesh belt of a continuous belt dryer to a thickness of 10-25 mm; a two-stage gradient temperature and humidity airflow is used to penetrate the wet residue layer. First stage of treatment: In a section 30%-40% of the total treatment section from the dryer inlet, a circulating airflow with a temperature of 40-55 ℃ and a relative humidity of 60%-75% is introduced from top to bottom into the wet slag layer. The airflow velocity is 0.8-1.2 m / s, and the treatment time is 3-6 minutes. Second stage treatment: Immediately following the first stage treatment, a dry airflow with a temperature of 55-65 ℃ and a relative humidity of 30%-45% is introduced into the wet slag layer from bottom to top, with an airflow velocity of 1.5-2.0 m / s and a treatment time of 4-8 minutes; The mesh size of the conveyor belt is 1.0-2.0 mm, and a periodic micro-vibration device is provided below the second processing area to vibrate the conveyor belt in that area. The vibration frequency is 5-8 Hz and the amplitude is 1-3 mm.

[0012] The mulberry pomace obtained through the aforementioned gentle separation often retains a sticky film on its surface, composed of high-concentration sugar solution and pectin. If directly subjected to high-temperature drying, this film will quickly harden and form a crust due to rapid evaporation of moisture, sealing the surface micropores and making it difficult for internal moisture to migrate outward. This leads to problems such as reduced drying efficiency, uneven moisture content inside and outside the dried fruit, hardening of texture, and decreased surface gloss. To address this issue, the pomace undergoes a two-stage gradient temperature and humidity airflow penetration treatment before drying: First, a medium-temperature and high-humidity airflow gently penetrates the pomace layer from top to bottom, removing some free moisture without causing rapid surface crusting. At the same time, the appropriate humidity slows down the excessive concentration of surface sugar solution and pectin, initially reducing viscosity. Subsequently, a higher-temperature and lower-humidity airflow penetrates from bottom to top at a higher speed, combined with periodic micro-vibrations at the bottom of the conveyor belt. This combined effect not only helps maintain and expand the pore structure inside the wet residue, enhancing the contact efficiency between airflow and material and promoting the migration of internal moisture to the surface, but also the synergy between airflow direction and vibration causes the wet residue to tumble and rearrange slightly, breaking up any potential local adhesions and ensuring uniform airflow penetration. This pre-established open porous structure, conducive to gradient moisture diffusion, lays a solid foundation for subsequent efficient and uniform drying, thus contributing to the final product of plump, uniformly textured dried mulberries.

[0013] Preferably, in step S4, the sterilization and bottling of the mulberry juice are achieved in the following manner: The clarified mulberry juice obtained in step S3 is pumped into the preheating section of the tubular flash sterilization system, and the juice temperature is uniformly raised from the ambient temperature to 68-72 ℃ within 3-5 seconds. The preheated mulberry juice is introduced into a holding tube. The inner wall of the holding tube has a corrugated structure with periodic contraction and expansion. The inner diameter of the contraction part of the corrugation is 60%-70% of the inner diameter of the expansion part, and the spacing between adjacent corrugations is 1.2-1.5 times the inner diameter of the tube. The mulberry juice flows through the holding tube at a flow rate of 1.5-2.5 m / s for 8-12 seconds. During this process, the juice temperature is maintained within the range of 68-72 ℃. The mulberry juice flowing out of the holding tube enters the vacuum flash evaporation chamber. The absolute pressure of the vacuum flash evaporation chamber is controlled at 15-25 kPa. The mulberry juice spreads and flows down the heated wall in the chamber in the form of a film with a thickness of 0.5-1.5 mm and a residence time of 1-3 seconds, so that the juice temperature drops instantly from 68-72 ℃ to 40-45 ℃, while flash evaporation removes 5%-10% of the volume of free water from the juice. After flash evaporation and cooling, the mulberry juice is aseptically introduced into a filling buffer tank. The filling buffer tank is filled with food-grade nitrogen and maintained at a positive pressure of 0.5-1.5 kPa. The residence time of the juice in the buffer tank does not exceed 30 seconds. Subsequently, the juice is injected into pre-sterilized packaging containers through an aseptic filling valve. The filling process is carried out under the protection of a nitrogen curtain, which covers the entire exposed space between the filling valve outlet and the container opening. The flow rate of nitrogen in the curtain is 0.3-0.6 m / s, and the temperature is 22-26 ℃. After filling, the package is sealed, and within 3-5 minutes after sealing, the entire sealed package is subjected to pulsed electron beam irradiation treatment with an intensity of 5-15 kGy and a duration of 10-20 seconds. The energy of the electron beam is 5-8 MeV and the pulse frequency is 50-100 Hz.

[0014] While mulberry juice obtained through a gentle boiling extraction process retains heat-sensitive components such as anthocyanins to a large extent, it faces a dilemma in the subsequent sterilization process: if conventional high-temperature heat sterilization is used, it will cause secondary heat damage to the retained nutrients; if only a lower temperature is used, it may not be able to completely inactivate heat-resistant microbial spores and enzymes, making it difficult to meet commercial sterility requirements, and there is also a risk of introducing secondary contamination during the filling process. To resolve this contradiction, this invention employs a multi-stage synergistic processing flow: First, the juice is preheated at a relatively low temperature of 68-72°C and flows through a retaining tube with a corrugated inner wall. The resulting periodic turbulence ensures uniform temperature and initially weakens microbial activity through mechanical shearing. Subsequently, the juice enters a vacuum flash chamber for instantaneous cooling. This process rapidly removes the juice from the heat-affected zone while also removing some free water, slightly increasing the solids concentration to reduce water activity. The entire filling process is conducted under positive pressure protection with food-grade nitrogen, physically isolating oxygen and external contaminants through a nitrogen curtain. Finally, the sealed packaging is subjected to short-duration, high-intensity pulsed electron beam irradiation. The core of this combined strategy lies in shifting the primary sterilization load from continuous thermal action to non-thermal physical processes (such as turbulent shearing, vacuum dehydration, and cold irradiation), thereby ensuring the product meets commercial sterility standards and extends shelf life while minimizing the cumulative impact of the entire sterilization and filling process on heat-sensitive nutrients.

[0015] Preferably, in step S4, the wet mulberry residue is dried to obtain dried mulberry, specifically achieved through the following method: The intact mulberry fruit residue is evenly spread on the conveyor belt of a continuous multi-layer belt dryer, with a thickness of 15-30 mm. The dryer is divided into three drying stages along the material's direction of travel: a penetration equilibrium stage, a gradient analysis stage, and a shaping and slow drying stage. The length of the permeation equilibrium section is 15%-25% of the total drying path. In the permeation equilibrium section, high-humidity circulating hot air with a temperature of 45-55 ℃ and a relative humidity of 85%-95% is introduced into the wet slag layer from top to bottom, and the hot air velocity is 0.5-0.8 m / s. At the same time, an ultrasonic atomizing device is installed below the conveyor belt in the permeation equilibrium section, which intermittently sprays pure water droplets with a particle size of 10-30 micrometers and a temperature of 45-55 ℃ from bottom to top. The spraying cycle is 2 minutes of operation and 1 minute of rest, so that the lower surface of the wet slag layer can also be in contact with the high-humidity environment. The gradient analysis section is located downstream of the permeation equilibrium section, and its length accounts for 50%-60% of the total drying path. It employs variable temperature and humidity gradient control, specifically as follows: Along the material travel direction, the gradient analysis section is further divided into four sub-regions; The conditions for the first sub-zone are: temperature 55-60 ℃, relative humidity 70-75%, wind speed 1.0-1.2 m / s, and air supply from top to bottom; The conditions for the second sub-zone are: temperature 60-65 ℃, relative humidity 55-60%, wind speed 1.2-1.5 m / s, and air supply from bottom to top; The conditions for the third sub-zone are: temperature 65-68 ℃, relative humidity 40-45%, wind speed 1.5-1.8 m / s, and air supply from top to bottom; The conditions for the fourth sub-zone are: temperature 68-72 ℃, relative humidity 30-35%, wind speed 1.2-1.5 m / s, and air supply from bottom to top; The setting and slow-drying section is downstream of the gradient drying section, and its length accounts for 20%-30% of the total drying path. Temperature zone control is employed in this section. The length of the front dry and hot zone is 40%-50% of the total length of the shaping and slow drying section. The front dry and hot zone is supplied with dry and hot air at a temperature of 58-62 ℃ and a relative humidity of 25-30%, with a wind speed of 0.8-1.0 m / s, and the air is supplied from bottom to top. The length of the rear dry and cold zone is 30%-40% of the total length of the shaping and slow drying section. The rear dry and cold zone is supplied with dry and cold air at a temperature of 45-50 ℃ and a relative humidity of 20-25%, with a wind speed of 1.0-1.2 m / s, and the air is supplied from top to bottom. At the end of the shaping and slow-drying section, a cooling zone is set up. The length of the end cooling zone is 20%-30% of the total length of the shaping and slow-drying section. Room temperature air at 20-25 ℃ is introduced to cool the dried mulberries to 30-35 ℃, resulting in dried mulberries with a moisture content of 15%-20%.

[0016] While the anthocyanins and other components of mulberry pomace obtained through gentle boiling and extraction are well preserved, their structure is loose and their mechanical strength is low. If conventional high-temperature or single-process drying is used, the rapid evaporation of surface moisture and the delayed migration of internal moisture can easily lead to a surface hardening-inner-outer-dry phenomenon, resulting in uneven drying, prolonged drying time, and a stiff and brittle product texture. Furthermore, prolonged continuous heat exposure may cause slow thermal oxidation of the retained anthocyanins. To address this, the present invention implements a staged and precisely controlled drying strategy: First, a stable high-humidity environment is created in the penetration equilibrium section, combined with bottom ultrasonic atomization, so that the moisture inside and outside the pomace is redistributed and tends to equilibrium under gentle heat, softening the surface and preheating the entire material; then, in the gradient desorption section, the temperature, humidity, and alternating airflow direction are gradually changed through four sub-zones to form a controllable vapor pressure gradient, continuously and uniformly driving the moisture to migrate and evaporate from the inside to the surface, and the alternating airflow prevents drying dead zones; finally, in the shaping and slow drying section, a relatively low drying temperature is used for zoned treatment, supplemented by final cooling. The entire process achieves efficient dehydration with a low and uniform heat load by precisely controlling the kinetic conditions of heat and moisture transfer. While obtaining ideal moisture content and a fluffy and porous morphology, it maximizes the protection of the existing heat-sensitive nutrients and structural integrity in the wet residue.

[0017] Preferably, in step S4, after obtaining dried mulberries with a moisture content of 15%-20%, the process further includes an integrated step of static pressure balancing and inert gas encapsulation of the dried mulberries, specifically: Within 3 minutes of production, the dried mulberries, cooled to 30-35 ℃, are transferred as a whole to an integrated processing chamber that can be sealed. The interior space of the integrated processing chamber is divided into an upper material area and a lower gas buffer distribution area by a breathable support net. After closing the chamber door, first perform a vacuuming operation on the integrated processing chamber, reducing the absolute pressure inside the chamber to 10-15 kPa within 30-60 seconds and maintaining it for 60-90 seconds; Subsequently, food-grade nitrogen or argon gas that has undergone deoxygenation and deep drying is introduced into the gas buffer distribution area of ​​the integrated processing chamber. The gas flow rate is controlled to allow the pressure inside the chamber to recover to normal pressure at a uniform rate within 2-3 minutes. Then, inert gas is introduced to raise the pressure inside the chamber to 105-110 kPa and maintain it under positive pressure for 5-8 minutes. During this period, the gas in the gas buffer distribution area diffuses evenly through the breathable support net and penetrates the upper mulberry dry layer. After the holding phase ends, under the condition of maintaining positive pressure inside the warehouse, the automatic packaging system built into the integrated processing warehouse is started to fill the dried mulberries quantitatively into flexible high-barrier packaging bags that are pre-placed in the warehouse and have an iron-based deoxidizer film attached to the inner surface. During the filling process, an inert gas flow with the same atmosphere as inside the warehouse is continuously introduced into the area above the opening of the packaging bag, forming a downward flowing air curtain covering the bag opening to maintain a local, high-purity positive pressure inert gas atmosphere at the filling station. After filling, the packaging bags are heat-sealed in a positive pressure inert atmosphere inside the chamber, and the sealed packaging bags are removed through a sterile transfer valve on the chamber wall.

[0018] The mulberry dried fruit, produced through gradient and gentle drying, develops an open, porous structure. While this imparts excellent rehydration and texture, it also significantly increases the surface area exposed to oxygen. This means that during subsequent storage and distribution, residual oxygen within the pores and slow infiltration from the outside can cause long-term, slow oxidative degradation of highly preserved anthocyanins and other easily oxidized components, affecting the product's color and nutritional stability throughout its shelf life. Therefore, shortly after drying and cooling, the dried mulberry fruit is transferred to a sealable integrated processing chamber. First, a vacuum is used to quickly remove most of the free gas and some of the gas from the pores, creating a negative pressure environment. Then, food-grade inert gas, deoxygenated and dried, is introduced at a uniform rate, restoring the chamber pressure to atmospheric pressure and further increasing it to a slightly positive pressure, which is maintained for a period. The pressure and concentration gradient drive the inert gas to diffuse deep into the pores of the material, replacing residual oxygen. Finally, under this continuously maintained positive pressure inert atmosphere, the mulberry fruit is directly and quantitatively filled and heat-sealed. This integrated process uses physical displacement to maximize the removal of oxygen from the inside and surface of the dried mulberries before packaging, and completes the final packaging under the protection of inert gas throughout the process, thereby effectively reducing the risk of oxidative deterioration of the product during storage.

[0019] Preferably, before step S1, a pretreatment cleaning step of low-temperature microbubble and airflow synergy is included, specifically: Whole, fresh mulberries are placed in a horizontally positioned drum-type pretreatment chamber. The walls of the drum-type pretreatment chamber have a porous structure, and the inner walls are lined with food-grade flexible padding. An aqueous solution containing 0.01-0.05 g / 100mL polysorbate 80 and 0.5-1.0 g / 100mL food-grade citric acid, at a temperature of 8-15 ℃, is injected into the pretreatment chamber. The liquid level is 50% of the volume of the mulberries submerged. The drum is then started and rotated at a constant speed of 3-6 rpm for 2-4 minutes. Simultaneously, clean air is introduced into the liquid through a porous tube located at the center of the drum shaft, generating microbubbles with a particle size of 50-200 micrometers at a flow rate of 0.1-0.3 m³ / h. 3 / (min·m 3 liquid); After the rotation and microbubble treatment are completed, drain the cleaning liquid in the pretreatment chamber; then, keep the drum rotating at a speed of 5-8 rpm, and at the same time, axially introduce clean air with a temperature of 20-25 ℃ and a relative humidity of ≤40% that has been filtered and dehumidified from one end of the drum, with an airflow speed of 2-4 m / s, and continue blowing for 3-5 minutes to remove the water film adhering to the surface of the mulberry. After being blown, the mulberries are transferred to the processing device in step S1 for steam treatment.

[0020] Before steam treatment, mulberries may have dust, microorganisms, and trace amounts of fat-soluble contaminants adhering to their surface. If not effectively cleaned, these impurities may be fixed to the peel or penetrate the interior under the subsequent high-temperature steam treatment, affecting not only the purity and safety of the juice but also increasing the sterilization load due to residual microorganisms and potentially interfering with the uniform permeability of steam to epidermal cells. Therefore, this invention employs a combined physical cleaning process: First, the mulberries are placed in a drum-type pretreatment chamber. A low-temperature aqueous solution containing trace amounts of surfactants and citric acid, combined with the slow rotation of the drum and the introduction of microbubbles, works together to suspend and peel off various surface contaminants through the localized microjet flow generated by the collapse of microbubbles and the gentle chemical action of the solution, without applying mechanical friction. After the cleaning solution is discharged, low-temperature, low-humidity clean air is immediately and continuously blown along the drum's axial direction to quickly and evenly remove the residual water film from the fruit surface. This pretreatment method provides a clean, dry, and temperature-uniform material starting state for subsequent steam treatment, helping to ensure the consistency and effectiveness of the steam treatment steps, thus laying the foundation for the smooth progress of the entire processing flow.

[0021] This invention offers at least the following beneficial effects: By combining short-time steam treatment with precise programmed cooling, the overall heat load during processing is significantly reduced, effectively preserving heat-sensitive nutrients such as anthocyanins and original flavor compounds in mulberries. Simultaneously, the gentle solid-liquid separation technology and segmented gradient drying strategy employed maintain the morphological integrity of the mulberry pulp while obtaining highly clear juice, laying the foundation for producing high-quality dried mulberries with plump shapes and good rehydration properties. Furthermore, throughout the entire process from pretreatment, separation, sterilization to final packaging, physical methods such as inert gas protection, non-thermal sterilization, and vacuum inert gas replacement are used to collaboratively create a low-oxygen, low-heat accumulation processing environment. This further enhances the nutritional stability and overall quality of the product while ensuring its microbial safety and extending shelf life.

[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0023] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0024] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0025] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0026] Example 1 A method for co-producing and processing mulberry fruit based on mild boiling extraction and anthocyanin stabilization protection includes the following steps: S1: Saturated Steam Treatment Five kg of whole, fresh, and unrotten mulberries are placed in a processing device. The device includes an inner chamber and an outer chamber. The inner chamber has a drain outlet at its bottom and a steam inlet at its top. The inner chamber is fitted inside the outer chamber, forming a collection chamber between their bottoms. The outer chamber has a drain outlet at its bottom. An external saturated steam pipe passes through the outer chamber and connects to the steam inlet of the inner chamber. Saturated steam at 110°C is introduced into the inner chamber and processed for 60 seconds.

[0027] S2: Programmed cooling and heat preservation Immediately after step S1, the mulberries are subjected to a programmed cooling process. Within 5 minutes, the overall temperature of the mulberry material is uniformly reduced to 70°C by adjusting the steam supply and supplementing it with external circulating cooling water (without direct contact with the material). Subsequently, the temperature is maintained at 70°C for another 30 minutes.

[0028] S3: Solid-liquid separation After the heat preservation in step S2, the mixture of mulberries and juice is subjected to solid-liquid separation. The specific operation is as follows: Let the mixture stand for 10 minutes to allow the wet mulberry pulp to settle naturally to the bottom of the inner liner. Then, drain the clear mulberry juice through the drain port of the inner liner to obtain clear mulberry juice. The remaining sediment (wet mulberry pulp) is intact and is removed from the inner liner for later use.

[0029] S4: Product Preparation 1) After the clarified mulberry juice obtained in step S3 is subjected to routine pasteurization (85 ℃, 30 seconds), it is immediately aseptically filled to obtain the mulberry juice product.

[0030] 2) Spread the intact mulberry fruit residue obtained in step S3 evenly on a drying tray, place it in a hot air drying oven, and dry it at 65 ℃ until the moisture content is about 18% to obtain dried mulberry fruit product.

[0031] Example 2 The method of Example 1 is used, except that before performing the programmed cooling in step S2, a food-grade inert gas, either nitrogen or carbon dioxide, is continuously introduced into the mulberry and mulberry juice mixture in the inner liner after the treatment in step S1 for 10 minutes. Other operations are the same as in Example 1.

[0032] Example 3 The method of Example 2 is used, except that in step S3, the solid-liquid separation of the mixture after the heat preservation treatment in step S2 is specifically achieved in the following way: After the heat preservation treatment in step S2, at least 60% of the volume of mulberry juice is discharged through the drain port of the inner tank to obtain the primary clarified liquid. The mulberry pulp residue that has settled at the bottom of the inner liner is transferred together with the remaining mixture to a horizontally set up drain conveyor belt equipped with a vibrating screen. The vibrating screen has a mesh size of 3 mm, a vibration frequency of 12 Hz, and an amplitude of 3 mm. During the vibrating conveying process, multiple low-pressure wide-width fan-shaped airflow nozzles arranged above the drain conveyor belt continuously blow the mulberry pulp residue layer on the conveyor belt at a wind speed of 0.8 m / s and a temperature of 30 ℃. The liquid drained through the vibrating screen is collected and combined with the primary clarified liquid. It is then filtered through a static tubular filter with a pore size of 125 micrometers to obtain clarified mulberry juice. The material after blowing and draining is the intact mulberry wet residue. Other operations are the same as in Example 2.

[0033] Example 4 The method used in Example 3 differs in that, after obtaining the intact mulberry fruit residue through blowing and draining, and before drying, a pretreatment is performed on the surface of the mulberry fruit residue for slow-release drying and maintenance of its microporous structure. Specifically: The wet mulberry residue is evenly spread on the mesh belt of a continuous belt dryer to a thickness of 10-25 mm; a two-stage gradient temperature and humidity airflow is used to penetrate the wet residue layer. First stage of treatment: In the area 35% of the total treatment section from the dryer inlet, a circulating airflow with a temperature of 48 ℃ and a relative humidity of 68% is introduced from top to bottom into the wet slag layer at a speed of 1.0 m / s and a treatment time of 5 minutes. Second stage of treatment: Immediately following the first stage of treatment, a dry airflow with a temperature of 60 ℃ and a relative humidity of 38% is introduced into the wet slag layer from bottom to top. The airflow velocity is 1.8 m / s and the treatment time is 6 minutes. The mesh size of the conveyor belt is 1.5 mm, and a periodic micro-vibration device is provided below the second processing area to vibrate the conveyor belt in that area. The vibration frequency is 6 Hz and the amplitude is 2 mm.

[0034] Other operations are the same as in Example 3.

[0035] Example 5 The method of Example 4 is adopted, except that the clarified mulberry juice obtained in step S3 is pumped into the preheating section of the tubular flash sterilization system, and the juice temperature is uniformly raised from the ambient temperature to 70°C within 4 seconds. The preheated mulberry juice is introduced into a holding tube. The inner wall of the holding tube has a corrugated structure with periodic contraction and expansion. The inner diameter of the contraction part of the corrugation is 65% of the inner diameter of the expansion part, and the spacing between adjacent corrugations is 1.35 times the inner diameter of the tube. The mulberry juice flows through the holding tube at a flow rate of 2.0 m / s for 10 seconds. During this process, the juice temperature is maintained within 70 ℃. The mulberry juice flowing out of the holding tube enters the vacuum flash evaporation chamber. The absolute pressure of the vacuum flash evaporation chamber is controlled at 20 kPa. The mulberry juice spreads and flows down the heated wall in the form of a film in the chamber. The film thickness is stably controlled at 1.0 mm and the residence time is 2 seconds, so that the juice temperature drops instantly from 70 ℃ to 43 ℃, while flash evaporation removes 8% of the volume of free water in the juice. After flash evaporation and cooling, the mulberry juice is aseptically introduced into a filling buffer tank. The filling buffer tank is filled with food-grade nitrogen and maintained at a positive pressure of 1.0 kPa. The residence time of the juice in the buffer tank does not exceed 30 seconds. Subsequently, the juice is injected into pre-sterilized packaging containers through an aseptic filling valve. The filling process is carried out under the protection of a nitrogen curtain, which covers the entire exposed space between the filling valve outlet and the container opening. The flow rate of nitrogen in the curtain is 0.45 m / s, and the temperature is 24 ℃. After filling, the package is sealed, and within 4 minutes of sealing, the entire sealed package is subjected to pulsed electron beam irradiation treatment with an intensity of 10 kGy and a duration of 15 seconds. The energy of the electron beam is 6.5 MeV and the pulse frequency is 75 Hz.

[0036] Example 6 The method of Example 5 is adopted, except that in step S4, the wet mulberry residue is dried to obtain dried mulberry, which is specifically achieved in the following way: The intact mulberry fruit residue is evenly spread on the conveyor belt of a continuous multi-layer belt dryer to a thickness of 22 mm. The dryer is divided into three drying stages along the material's direction of travel: a penetration equilibrium stage, a gradient analysis stage, and a shaping and slow drying stage. The length of the permeation equilibrium section is 20% of the total drying path. In the permeation equilibrium section, high-humidity circulating hot air with a temperature of 50 ℃ and a relative humidity of 90% is introduced into the wet slag layer from top to bottom, and the hot air velocity is 0.65 m / s. At the same time, an ultrasonic atomizing device is installed below the conveyor belt in the permeation equilibrium section, which intermittently sprays pure water droplets with a particle size of 20 micrometers and a temperature of 50 ℃ from bottom to top. The spraying cycle is 2 minutes of operation and 1 minute of rest, so that the lower surface of the wet slag layer can also be in contact with the high-humidity environment. The gradient analysis section is located downstream of the osmosis equilibrium section, and its length is 55% of the total drying path. It employs variable temperature and humidity gradient control, specifically as follows: Along the material travel direction, the gradient analysis section is further divided into four sub-regions; The conditions for the first sub-zone are: temperature 58 ℃, relative humidity 72%, wind speed 1.1 m / s, and air supply from top to bottom; The conditions for the second sub-zone are: temperature 62 ℃, relative humidity 58%, wind speed 1.35 m / s, and air supply from bottom to top; The conditions for the third sub-zone are: temperature 66 ℃, relative humidity 42%, wind speed 1.65 m / s, and air supply from top to bottom; The conditions for the fourth sub-zone are: temperature 70 ℃, relative humidity 32%, wind speed 1.35 m / s, and air supply from bottom to top; The setting and slow-drying section is downstream of the gradient analysis section, and its length accounts for 25% of the total drying path. Temperature zone control is employed in this section. The length of the front dry and hot zone is 45% of the total length of the shaping and slow drying section. The front dry and hot zone is supplied with dry and hot air at a temperature of 60 ℃ and a relative humidity of 28%, with a wind speed of 0.9 m / s, and the air is delivered from bottom to top. The length of the rear dry-cooling zone is 35% of the total length of the shaping and slow-drying section. The rear dry-cooling zone is supplied with dry-cool air at a temperature of 48 ℃ and a relative humidity of 22%, with a wind speed of 1.1 m / s, and the air is delivered from top to bottom. At the end of the shaping and slow-drying section, a cooling zone is set up. The length of the end cooling zone is 25% of the total length of the shaping and slow-drying section. Room temperature air at 22 ℃ is introduced to cool the dried mulberries to 32 ℃, resulting in dried mulberries with a moisture content of 18%.

[0037] Example 7 The method of Example 6 is used, except that the dried mulberries cooled to 32°C are transferred as a whole to a sealable integrated processing chamber within 3 minutes after production. The internal space of the integrated processing chamber is divided into an upper material area and a lower gas buffer distribution area by a breathable support net. After closing the chamber door, the integrated processing chamber is first evacuated to reduce the absolute pressure inside the chamber to 13 kPa within 45 seconds and maintain it for 75 seconds. Subsequently, food-grade nitrogen or argon gas that has undergone deoxygenation and deep drying is introduced into the gas buffer distribution area of ​​the integrated processing chamber. The gas flow rate is controlled to allow the pressure inside the chamber to recover to normal pressure at a uniform rate within 2.5 minutes. Then, inert gas is introduced to raise the pressure inside the chamber to 108 kPa and maintain it under positive pressure for 6 minutes. During this period, the gas in the gas buffer distribution area diffuses evenly through the permeable support net and penetrates the upper mulberry dry layer. After the holding phase ends, under the condition of maintaining positive pressure inside the warehouse, the automatic packaging system built into the integrated processing warehouse is started to fill the dried mulberries quantitatively into flexible high-barrier packaging bags that are pre-placed in the warehouse and have an iron-based deoxidizer film attached to the inner surface. During the filling process, an inert gas flow with the same atmosphere as inside the warehouse is continuously introduced into the area above the opening of the packaging bag, forming a downward flowing air curtain covering the bag opening to maintain a local, high-purity positive pressure inert gas atmosphere at the filling station. After filling, the packaging bags are heat-sealed in a positive pressure inert atmosphere inside the chamber, and the sealed packaging bags are removed through a sterile transfer valve on the chamber wall.

[0038] Example 8 The method of Example 7 is used, except that whole fresh mulberries are placed in a horizontally arranged drum-type pretreatment chamber. The walls of the drum-type pretreatment chamber have a porous structure and the inner wall is lined with a food-grade flexible pad. An aqueous solution containing 0.03 g / 100 mL polysorbate 80 and 0.75 g / 100 mL food-grade citric acid, at a temperature of 12 ℃, was injected into the pretreatment chamber. The liquid level was 50% of the volume of the mulberries submerged. The drum was then started and rotated at a constant speed of 4.5 rpm for 3 minutes. Simultaneously, clean air was introduced into the liquid through a porous tube located at the center of the drum shaft, generating microbubbles with an average particle size of 125 micrometers at a flow rate of 0.2 m³ / s. 3 / (min·m 3 liquid); After the rotation and microbubble treatment are completed, the cleaning liquid in the pretreatment chamber is drained. Then, the drum continues to rotate at a speed of 6.5 rpm, while clean air with a temperature of 23 ℃ and a relative humidity of ≤40% that has been filtered and dehumidified is axially introduced from one end of the drum at a speed of 3 m / s for 4 minutes. After removing the water film attached to the surface of the mulberry, there is no obvious free water film on the surface of the mulberry and it feels dry to the touch. After being blown, the mulberries are transferred to the processing device in step S1 for steam treatment.

[0039] Comparative Example 1 A method for processing mulberries includes the following steps: Place 5 kg of whole, fresh mulberries in a pressure cooker, add an equal weight of water, heat to 95 ℃ and maintain the cooking temperature for 40 minutes.

[0040] After boiling and extracting the mulberries, remove them to obtain mulberry juice and mulberry pulp.

[0041] The mulberry juice is sterilized at high temperature (121 ℃, 5 seconds) and then bottled to obtain the mulberry juice product.

[0042] Spread the mulberry residue evenly and dry it in a 70 ℃ hot air drying oven until the moisture content is about 18% to obtain dried mulberry.

[0043] Comparative Example 2 A method for processing mulberries includes the following steps: S1: Place 5 kg of whole fresh mulberries in the treatment device and treat with 110 ℃ saturated steam for 60 seconds.

[0044] S2: After processing, without performing a cooling program, directly introduce 70 ℃ hot air into the device to gradually reduce the material temperature to 70 ℃ and maintain it for 30 minutes.

[0045] S3: After heat preservation, the mixture is subjected to solid-liquid separation (in the same way as in Example 1) to obtain mulberry juice and mulberry wet residue.

[0046] S4: Pasteurize the mulberry juice (85 ℃, 30 seconds) and then fill it; dry the wet mulberry pomace at 65 ℃ to a moisture content of about 18% to obtain dried mulberry.

[0047] Comparative Example 3 A method for processing mulberries includes the following steps: S1: Place 5 kg of whole fresh mulberries in the treatment device and treat with 100 ℃ saturated steam for 30 seconds.

[0048] S2: Cool the overall temperature of the material to 70°C within 5 minutes and hold at 70°C for 30 minutes.

[0049] S3-S4: Same as Example 1.

[0050] Effect test I. Anthocyanin content and retention rate Method: High performance liquid chromatography (HPLC) was used.

[0051] Indicator: The total anthocyanin content in fresh mulberries, mulberry juice obtained from each case, and dried mulberries was determined.

[0052] calculate: Anthocyanin retention rate in fruit juice (%) = (Total anthocyanins in finished fruit juice / Total anthocyanins in raw mulberry fruit) × 100%; Anthocyanin retention rate in dried fruit (%) = (Total anthocyanins in finished dried fruit / Total anthocyanins in raw mulberry fruit) × 100%; Total anthocyanin retention rate (%) = (Total anthocyanins in juice + Total anthocyanins in dried fruit) / Total anthocyanins in raw mulberry fruit × 100%.

[0053] The results are shown in Table 1.

[0054] Table 1. Anthocyanin content and retention rate As shown in Table 1, Examples 1 to 8 using the method of the present invention all showed a progressively increasing trend in the retention rate of anthocyanins in juice, dried fruit, and total co-products. Among them, the total co-product retention rate of Example 8 reached 86.7%, which was significantly higher than that of the comparative examples. This indicates that the present invention, through gentle boiling extraction, inert gas protection, and subsequent synergistic processes, can not only effectively retain anthocyanins, but may also improve the dissolution efficiency of some components due to improved cell permeability, thus achieving dual optimization of nutrition and yield.

[0055] II. Quality and Sensory Properties of Fruit Juice Products 1. Clarity and stability: Methods: The transmittance (%) at a wavelength of 660 nm was determined by spectrophotometry; or the particle size distribution of insoluble particles was analyzed by laser particle size analyzer; and the precipitation was observed by accelerated testing (stored at 37℃).

[0056] Indicators: transmittance, turbidity (NTU), sedimentation rate (%).

[0057] The results are shown in Table 2.

[0058] Table 2. Clarity and Stability of Fruit Juice Table 2 shows that the transmittance of the juice in the example group gradually increased to 96.2%, the turbidity decreased to below 4.8 NTU, and the sedimentation rate was less than 0.5%. In contrast, the transmittance of Comparative Example 1 was only 75.3%, and the turbidity was as high as 35.6 NTU. This indicates that the mild separation and filtration process used in this invention can significantly improve the clarity and storage stability of the juice, and reduce particle residue and sedimentation.

[0059] 2. Color Method: The colorimeter was used to measure L (lightness), a (red-green value), b (yellow-blue value), and the total color difference ΔE.

[0060] Indicators: L*, a*, b*, ΔE (relative to freshly squeezed juice).

[0061] The results are shown in Table 3.

[0062] Table 3. Juice Color (Color Difference) As shown in Table 3, the ΔE value of the Example Group gradually decreased to 2.5 as the process was improved, the a value (redness) increased and the b value (yellowness) decreased, indicating that the color of the juice was closer to the purplish-red tone of freshly squeezed juice. The ΔE of Comparative Example 1 was as high as 8.2, showing that its color deviated significantly due to high-temperature processing, which confirms the advantages of the present invention in color protection.

[0063] 3. Soluble solids (°Brix) and pH value: Methods: refractometer, pH meter.

[0064] Indicators: °Brix, pH.

[0065] The results are shown in Table 4.

[0066] Table 4 Soluble solids and pH of fruit juice As shown in Table 4, the soluble solids content of the juice in the example group gradually increased to 13.7°Brix, and the pH value remained stable between 3.5 and 3.8, showing a higher concentration and suitable acidity overall; while the °Brix of Comparative Example 1 was only 10.2 and the pH was 4.2, indicating that traditional boiling extraction may have resulted in solids loss due to excessive water input or thermal degradation, and the acidity control was poor.

[0067] 4. Sensory evaluation Methods: Quantitative descriptive analysis (QDA) or preference rating was conducted by a trained sensory evaluation team.

[0068] Indicators: color, aroma (fruity, cooked, etc.), taste (sweetness, acidity, freshness, bitterness), and overall acceptability.

[0069] The results are shown in Table 5.

[0070] Table 5 Sensory Evaluation of Fruit Juice (Score: 1-10 points) As shown in Table 5, the color, aroma, taste and overall acceptability scores of the Example Group steadily increased with process optimization, reaching a maximum of 9.6 points, indicating that the product was highly recognized by the tasters in terms of flavor, taste and appearance. The scores of Comparative Example 1 were all below 7 points, especially in aroma and taste, reflecting the negative impact of traditional high-temperature processing on flavor quality.

[0071] III. Product Quality and Sensory Properties of Dried Mulberries 1. Morphological integrity Method: Manual statistics.

[0072] Indicators: Whole fruit rate (%), Broken fruit rate (%), Average fruit size retention rate.

[0073] The results are shown in Table 6.

[0074] Table 6. Morphological Integrity of Dried Mulberries As shown in Table 6, the highest intact fruit rate in the Example Group was 95.2%, the lowest breakage rate was 2.5%, and the average particle size retention rate was close to 99%, indicating that the present invention effectively maintained the physical morphology of the dried fruit through gentle separation, pretreatment, and gradient drying. In contrast, the intact fruit rate in Comparative Example 1 was only 45.2%, and the breakage rate was as high as 38.5%, highlighting the destructive effect of traditional processes on the fruit residue structure.

[0075] 2. Color and surface condition Method: Same as the color determination of fruit juice; observe whether the surface is shiny or has a white bloom (sugar precipitation).

[0076] Indicators: L*, a*, b*, ΔE; Surface gloss description.

[0077] The results are shown in Table 7.

[0078] Table 7 Color and Surface Condition of Dried Mulberries As shown in Table 7, the L and a values ​​of the dried mulberries in the Example group gradually increased, and the surface gloss description improved from "relatively bright" to "very bright, without white frost", indicating that the appearance was bright and the surface was evenly dried. In contrast, the surface of Comparative Example 1 was dull and had white frost, reflecting product appearance defects caused by uneven drying or sugar precipitation.

[0079] IV. Processing Efficiency and Energy Consumption Indicators 1. Juice yield Method: Weighing and calculation.

[0080] Indicator: Weight of mulberry juice / Weight of raw mulberries × 100%.

[0081] Drying efficiency: Method: Record the time required to reach the target moisture content, or calculate the drying rate.

[0082] Indicators: Total drying time (h), average drying rate (% / h).

[0083] The results are shown in Table 8.

[0084] Table 8 Processing Efficiency and Energy Consumption Indicators As shown in Table 8, the juice yield of the Example Group gradually increased to 72.8%, the total drying time was shortened to 5.5 hours, and the average drying rate increased to 14.5% / h. This indicates that the present invention significantly improved dehydration efficiency by optimizing the drying process while increasing the juice yield. Comparative Example 1 had the lowest juice yield and the longest drying time, resulting in lower overall energy efficiency.

[0085] V. Safety and Storage Stability Indicators 1. Microbiological indicators Method: Determined using the national standard method.

[0086] Indicators: Total bacterial count, mold and yeast count, coliform bacteria, and pathogenic bacteria in mulberry juice.

[0087] The results are shown in Table 9.

[0088] Table 9 Microbiological Indicators (Total Colony Count: CFU / mL) As shown in Table 9, the total bacterial count and mold and yeast count of all example groups were extremely low or undetectable, and coliform bacteria and pathogenic bacteria were undetectable, meeting the requirements for commercial sterility. However, microorganisms were still detected in Comparative Example 1, indicating that the multi-stage non-thermal sterilization and aseptic filling system of the present invention can effectively ensure the microbiological safety of the product.

[0089] 2. Color and nutritional stability during storage Method: The product was stored under accelerated conditions (37°C, 75% relative humidity) and samples were taken after 6 months.

[0090] Indicators: Monitor anthocyanin retention rate, color (a* value), and peroxide value (for dried fruit).

[0091] The results are shown in Table 10.

[0092] Table 10 Color and nutritional stability during storage period As shown in Table 10, the anthocyanin retention rate of the Example Group was still as high as 99.8% after 6 months of accelerated storage, with minimal change in the a* value and a peroxide value below 0.3 meq / kg, indicating that the product had excellent color and nutritional stability during storage. In contrast, the anthocyanin retention rate of Comparative Example 1 was only 65.2%, and the peroxide value reached 8.5 meq / kg, reflecting its susceptibility to oxidation and deterioration. This further confirms the effectiveness and necessity of the present invention in extending shelf life.

[0093] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A method for the co-production and processing of mulberry fruit based on mild boiling extraction and anthocyanin stabilization protection, characterized in that, Includes the following steps: S1: Place whole, fresh mulberries in a processing device, introduce saturated steam at 105-115 ℃, and process for 60-120 seconds; The processing device includes an inner liner and an outer liner. The bottom of the inner liner is provided with an inner liner drain port and the top is provided with a steam inlet. The inner liner is fitted inside the outer liner, and the bottom of the inner liner and the bottom of the outer liner form a liquid collection chamber. The bottom of the outer liner is provided with an outer liner drain port. An external saturated steam pipe passes through the outer liner and is connected to the steam inlet. S2: Perform a programmed cooling process on the mulberries after step S1, reducing their overall temperature to 65-75 ℃ within 3-8 minutes, and then maintaining the temperature within the range of 65-75 ℃ for another 20-40 minutes. S3: Separate the solid and liquid components of the mulberry fruit after the heat preservation in step S2 to obtain clear mulberry juice and intact mulberry fruit wet residue. S4: Sterilize and fill the mulberry juice, and dry the wet mulberry residue to obtain dried mulberry.

2. The mulberry fruit co-processing method based on mild boiling extraction and anthocyanin stabilization protection according to claim 1, characterized in that, Before performing the cooling process in step S2, food-grade inert gas, which is nitrogen or carbon dioxide, is continuously introduced into the mixture of mulberry fruit and mulberry juice after step S1 for 5-15 minutes.

3. The mulberry fruit co-processing method based on mild boiling extraction and anthocyanin stabilization protection according to claim 1, characterized in that, In step S3, the solid-liquid separation of the mixture after the heat preservation treatment in step S2 is achieved in the following way: After the heat preservation treatment in step S2, at least 60% of the volume of mulberry juice is discharged through the drain port of the inner tank to obtain the primary clarified liquid. The mulberry pulp residue at the bottom of the inner liner, along with the remaining mixture, is transferred to a horizontally positioned drain conveyor belt equipped with a vibrating screen. The vibrating screen has an aperture of 2-4 mm, a vibration frequency of 10-15 Hz, and an amplitude of 2-5 mm. During the vibrating conveying process, multiple low-pressure, wide-width fan-shaped airflow nozzles arranged above the drain conveyor belt continuously blow the mulberry pulp residue layer on the conveyor belt at a wind speed of 0.5-1.0 m / s and a temperature of 25-35 ℃. The liquid drained through the vibrating screen is collected and combined with the primary clarified liquid. It is then filtered through a static tubular filter with a pore size of 100-150 micrometers to obtain clarified mulberry juice. The material after blowing and draining is the mulberry wet residue with intact shape.

4. The mulberry fruit co-processing method based on mild boiling extraction and anthocyanin stabilization protection according to claim 3, characterized in that, After the mulberry fruit residue is obtained by blowing and draining to obtain a complete shape, before drying, the pretreatment of the mulberry fruit residue includes surface slow-release drying and microporous structure maintenance, specifically: The wet mulberry residue is evenly spread on the mesh belt of a continuous belt dryer to a thickness of 10-25 mm; a two-stage gradient temperature and humidity airflow is used to penetrate the wet residue layer. First stage of treatment: In a section 30%-40% of the total treatment section from the dryer inlet, a circulating airflow with a temperature of 40-55 ℃ and a relative humidity of 60%-75% is introduced from top to bottom into the wet slag layer. The airflow velocity is 0.8-1.2 m / s, and the treatment time is 3-6 minutes. Second stage treatment: Immediately following the first stage treatment, a dry airflow with a temperature of 55-65 ℃ and a relative humidity of 30%-45% is introduced into the wet slag layer from bottom to top, with an airflow velocity of 1.5-2.0 m / s and a treatment time of 4-8 minutes; The mesh size of the conveyor belt is 1.0-2.0 mm, and a periodic micro-vibration device is provided below the second processing area to vibrate the conveyor belt in that area. The vibration frequency is 5-8 Hz and the amplitude is 1-3 mm.

5. The mulberry fruit co-processing method based on mild boiling extraction and anthocyanin stabilization protection according to claim 1, characterized in that, In step S4, the sterilization and bottling of the mulberry juice are specifically achieved through the following methods: The clarified mulberry juice obtained in step S3 is pumped into the preheating section of the tubular flash sterilization system, and the juice temperature is uniformly raised from the ambient temperature to 68-72 ℃ within 3-5 seconds. The preheated mulberry juice is introduced into a holding tube. The inner wall of the holding tube has a corrugated structure with periodic contraction and expansion. The inner diameter of the contraction part of the corrugation is 60%-70% of the inner diameter of the expansion part, and the spacing between adjacent corrugations is 1.2-1.5 times the inner diameter of the tube. The mulberry juice flows through the holding tube at a flow rate of 1.5-2.5 m / s for 8-12 seconds. During this process, the juice temperature is maintained within the range of 68-72 ℃. The mulberry juice flowing out of the holding tube enters the vacuum flash evaporation chamber. The absolute pressure of the vacuum flash evaporation chamber is controlled at 15-25 kPa. The mulberry juice spreads down the heated wall in the chamber in the form of a film with a thickness of 0.5-1.5 mm and a residence time of 1-3 seconds, so that the juice temperature drops instantly from 68-72 ℃ to 40-45 ℃, while flash evaporation removes 5%-10% of the volume of free water from the juice. After flash evaporation and cooling, the mulberry juice is aseptically introduced into a filling buffer tank. The filling buffer tank is filled with food-grade nitrogen and maintained at a positive pressure of 0.5-1.5 kPa. The residence time of the juice in the buffer tank does not exceed 30 seconds. Subsequently, the juice is injected into pre-sterilized packaging containers through an aseptic filling valve. The filling process is carried out under the protection of a nitrogen curtain, which covers the entire exposed space between the filling valve outlet and the container opening. The flow rate of nitrogen in the curtain is 0.3-0.6 m / s, and the temperature is 22-26℃. After filling, the package is sealed, and within 3-5 minutes after sealing, the entire sealed package is subjected to pulsed electron beam irradiation treatment with an intensity of 5-15 kGy and a duration of 10-20 seconds. The energy of the electron beam is 5-8 MeV and the pulse frequency is 50-100 Hz.

6. The mulberry fruit co-processing method based on mild boiling extraction and anthocyanin stabilization protection according to claim 1, characterized in that, In step S4, the wet mulberry residue is dried to obtain dried mulberry fruit, which is achieved through the following method: The intact mulberry fruit residue is evenly spread on the conveyor belt of a continuous multi-layer belt dryer, with a thickness of 15-30 mm. The dryer is divided into three drying stages along the material's direction of travel: a penetration equilibrium stage, a gradient analysis stage, and a shaping and slow drying stage. The length of the permeation equilibrium section is 15%-25% of the total drying path. In the permeation equilibrium section, high-humidity circulating hot air with a temperature of 45-55 ℃ and a relative humidity of 85%-95% is introduced into the wet slag layer from top to bottom, and the hot air velocity is 0.5-0.8 m / s. At the same time, an ultrasonic atomizing device is installed below the conveyor belt in the permeation equilibrium section, which intermittently sprays pure water droplets with a particle size of 10-30 micrometers and a temperature of 45-55 ℃ from bottom to top. The spraying cycle is 2 minutes of operation and 1 minute of rest, so that the lower surface of the wet slag layer can also be in contact with the high-humidity environment. The gradient analysis section is located downstream of the permeation equilibrium section, and its length accounts for 50%-60% of the total drying path. It employs variable temperature and humidity gradient control, specifically as follows: Along the material travel direction, the gradient analysis segment is further divided into four sub-regions; The conditions for the first sub-zone are: temperature 55-60 ℃, relative humidity 70-75%, wind speed 1.0-1.2 m / s, and air supply from top to bottom; The conditions for the second sub-zone are: temperature 60-65 ℃, relative humidity 55-60%, wind speed 1.2-1.5 m / s, and air supply from bottom to top; The conditions for the third sub-zone are: temperature 65-68 ℃, relative humidity 40-45%, wind speed 1.5-1.8 m / s, and air supply from top to bottom; The conditions for the fourth sub-zone are: temperature 68-72 ℃, relative humidity 30-35%, wind speed 1.2-1.5 m / s, and air supply from bottom to top; The setting and slow-drying section is downstream of the gradient drying section, and its length accounts for 20%-30% of the total drying path. Temperature zone control is employed in this section. The length of the front dry and hot zone is 40%-50% of the total length of the shaping and slow drying section. The front dry and hot zone is supplied with dry and hot air at a temperature of 58-62 ℃ and a relative humidity of 25-30%, with a wind speed of 0.8-1.0 m / s, and the air is supplied from bottom to top. The length of the rear dry and cold zone is 30%-40% of the total length of the shaping and slow drying section. The rear dry and cold zone is supplied with dry and cold air at a temperature of 45-50 ℃ and a relative humidity of 20-25%, with a wind speed of 1.0-1.2 m / s, and the air is supplied from top to bottom. At the end of the shaping and slow-drying section, a cooling zone is set up. The length of the end cooling zone is 20%-30% of the total length of the shaping and slow-drying section. Room temperature air at 20-25 ℃ is introduced to cool the dried mulberries to 30-35 ℃, resulting in dried mulberries with a moisture content of 15%-20%.

7. The mulberry fruit co-processing method based on mild boiling extraction and anthocyanin stabilization protection according to claim 6, characterized in that, In step S4, after obtaining dried mulberries with a moisture content of 15%-20%, the process further includes an integrated step of static pressure balancing and inert gas encapsulation of the dried mulberries, specifically: Within 3 minutes of production, the dried mulberries, cooled to 30-35 ℃, are transferred as a whole to an integrated processing chamber that can be sealed. The interior space of the integrated processing chamber is divided into an upper material area and a lower gas buffer distribution area by a breathable support net. After closing the chamber door, first perform a vacuuming operation on the integrated processing chamber, reducing the absolute pressure inside the chamber to 10-15 kPa within 30-60 seconds and maintaining it for 60-90 seconds; Subsequently, food-grade nitrogen or argon gas that has undergone deoxygenation and deep drying is introduced into the gas buffer distribution area of ​​the integrated processing chamber. The gas flow rate is controlled to allow the pressure inside the chamber to recover to normal pressure at a uniform rate within 2-3 minutes. Then, inert gas is introduced to raise the pressure inside the chamber to 105-110 kPa and maintain it under positive pressure for 5-8 minutes. During this period, the gas in the gas buffer distribution area diffuses evenly through the breathable support net and penetrates the upper mulberry dry layer. After the holding phase ends, under the condition of maintaining positive pressure inside the warehouse, the automatic packaging system built into the integrated processing warehouse is started to fill the dried mulberries quantitatively into flexible high-barrier packaging bags that are pre-placed in the warehouse and have an iron-based deoxidizer film attached to the inner surface. During the filling process, an inert gas flow with the same atmosphere as inside the warehouse is continuously introduced into the area above the opening of the packaging bag, forming a downward flowing air curtain covering the bag opening to maintain a local, high-purity positive pressure inert gas atmosphere at the filling station. After filling, the packaging bags are heat-sealed in a positive pressure inert atmosphere inside the chamber, and the sealed packaging bags are removed through a sterile transfer valve on the chamber wall.

8. The mulberry fruit co-processing method based on mild boiling extraction and anthocyanin stabilization protection according to claim 1, characterized in that, Before step S1, a pretreatment cleaning step of low-temperature microbubble and airflow synergy is included for whole fresh mulberries, specifically: Whole, fresh mulberries are placed in a horizontally positioned drum-type pretreatment chamber. The walls of the drum-type pretreatment chamber have a porous structure, and the inner walls are lined with food-grade flexible padding. An aqueous solution containing 0.01-0.05 g / 100mL polysorbate 80 and 0.5-1.0 g / 100mL food-grade citric acid, at a temperature of 8-15 ℃, is injected into the pretreatment chamber. The liquid level is 50% of the volume of the mulberries submerged. The drum is then started and rotated at a constant speed of 3-6 rpm for 2-4 minutes. Simultaneously, clean air is introduced into the liquid through a porous tube located at the center of the drum shaft, generating microbubbles with a particle size of 50-200 micrometers at a flow rate of 0.1-0.3 m³ / h. 3 / (min·m 3 liquid); After the rotation and microbubble treatment are completed, drain the cleaning liquid in the pretreatment chamber; then, keep the drum rotating at a speed of 5-8 rpm, and at the same time, axially introduce clean air with a temperature of 20-25 ℃ and a relative humidity of ≤40% that has been filtered and dehumidified from one end of the drum, with an airflow speed of 2-4 m / s, and continue blowing for 3-5 minutes to remove the water film adhering to the surface of the mulberry. After being blown, the mulberries are transferred to the processing device in step S1 for steam treatment.

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