Raspberry-probiotic co-fermented milk tea

Abstract

This invention relates to the field of food processing technology, specifically to a milk tea preparation process, and more specifically, to an innovative process for creating a fresh-locking, nutritious raspberry milk tea. It centers on raspberry-probiotic co-fermentation, integrating ultra-high pressure HPP sterilization and low-temperature freezing cell-wall breaking technology to achieve a differentiated blend of health, flavor, and texture. This technology is applicable to the functional beverage processing field and is suitable for the industrial production of specialty milk teas with high requirements for nutrient retention, flavor, and texture. It addresses the technical pain points of traditional raspberry milk tea, such as nutrient loss, flavor volatilization, sterilization damage to quality, and homogenized taste. Through the synergistic effect of multiple processes, it effectively locks in the natural nutrients of raspberries, preserves probiotic activity, and balances unique flavor with a delicate texture. This technology belongs to the intersection of functional beverage processing and food preservation technology.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a milk tea preparation process, and more specifically, to an innovative process for creating a fresh-locking, nutritious raspberry milk tea. It centers on raspberry-probiotic co-fermentation, integrating ultra-high pressure HPP sterilization and low-temperature freezing cell-wall breaking technology to achieve a differentiated blend of health, flavor, and texture. This technology is applicable to the functional beverage processing field and is suitable for the industrial production of specialty milk teas with high requirements for nutrient retention, flavor, and texture. It addresses the technical pain points of traditional raspberry milk tea, such as nutrient loss, flavor volatilization, sterilization damage to quality, and homogenized taste. Through the synergistic effect of multiple processes, it effectively locks in the natural nutrients of raspberries, preserves probiotic activity, and balances unique flavor with a delicate texture. This technology belongs to the intersection of functional beverage processing and food preservation technology. Background Technology

[0002] With the increasing health awareness of residents, the milk tea beverage market is transforming from a traditional flavor-oriented approach to one focused on "nutrition, functionality, and differentiation." Consumers' demands for milk tea are no longer limited to basic taste; they are paying more attention to the health attributes, natural flavors, and nutrient retention of the products. Specialty milk teas that combine flavor and health benefits have become the core trend in the industry. Raspberries, a fruit rich in anthocyanins, vitamins, dietary fiber, and various minerals, are a culinary and medicinal ingredient. Their sweet and sour flavor and unique nutritional components make them ideal for developing specialty milk tea products. This can effectively enrich the nutritional levels and flavor diversity of milk tea, satisfying consumers' pursuit of natural and healthy drinks. Existing research shows that the active ingredients in raspberries can be fully utilized for their nutritional value through proper processing, providing a good raw material foundation for the development of specialty beverages.

[0003] Probiotics, as live microorganisms beneficial to human gut health, have been widely used in the food processing industry. Combining probiotics with raspberries can improve the flavor and texture of raspberries through the fermentation effect of probiotics, while also endowing the product with health benefits such as gut health regulation, achieving the dual value of "fruit nutrition + probiotic health care". Lactic acid bacteria, as a commonly used probiotic, can significantly increase the total phenolic content of raspberry products through fermentation, improve aroma components, reduce unpleasant flavors, and further enhance the product's functionality and taste experience. Currently, the application of combining raspberries and probiotics is mainly concentrated in products such as fruit juice and fermented milk, and related processes have been optimized to a certain extent, such as determining the optimal parameters for raspberry fermentation through orthogonal experiments to improve product quality. However, its application in the milk tea industry is still in its initial stage, and existing related technologies have significant shortcomings.

[0004] Current raspberry-based milk tea processing methods mostly involve directly adding raspberry powder, juice, or fresh raspberry pulp, without employing a co-fermentation technique involving raspberries and probiotics. This not only fails to fully release the nutrients in raspberries and create a unique fermented flavor, but also makes it difficult to maintain the activity of probiotics in the long term, thus failing to fully realize their health benefits. Furthermore, the thick cell walls of raspberry pulp are difficult to break down using conventional processing methods, resulting in the incomplete dissolution of heat-sensitive nutrients such as anthocyanins and polyphenols, leading to the waste of some nutrients and affecting the smoothness of the milk tea's texture. Low-temperature freezing can effectively break down raspberry cell walls and promote nutrient dissolution. This technology has already been applied in products such as raspberry enzymes, but has not yet been used in raspberry milk tea processing.

[0005] In terms of sterilization processes, current milk tea processing mostly employs traditional heat sterilization processes such as ultra-high temperature (UHT) sterilization and pasteurization. While these processes achieve sterilization and preservation, the high temperatures severely damage heat-sensitive nutrients (such as vitamin C and anthocyanins) and the activity of probiotics in raspberries. They also lead to the loss of the raspberries' natural flavor and a deterioration in taste, failing to simultaneously preserve both nutrition and flavor. Ultra-high pressure (UHP) sterilization technology, as a commercially viable non-thermal processing technology, typically uses ultra-high hydrostatic pressures of 400-600 MPa. At room temperature, it achieves sterilization by disrupting microbial cell membranes and altering the higher-order structure of bacterial proteins, thus maximizing the preservation of food's nutrients and natural flavor. It is widely used in the sterilization of fruits, vegetables, and dairy products. However, HPP sterilization technology alone has limited effectiveness in inactivating some pressure-resistant bacteria and spores, and it cannot solve the problems of insufficient cell wall disruption and inadequate nutrient dissolution in raspberries. The combination of ultra-high pressure, low temperature, and cell wall disruption technology can improve sterilization and nutrient retention. This combination approach has been validated in fields such as meat processing, but it has not been applied to raspberry milk tea processing.

[0006] In terms of taste and freshness preservation, existing raspberry milk teas generally suffer from problems such as monotonous flavor, rough texture, easy loss of nutrients, and short shelf life, making it difficult to achieve a harmonious balance of health, flavor, and taste, and failing to meet consumers' demand for differentiated, high-quality, fresh-preserving, and nutritious milk tea. Low-temperature freezing and cell wall disruption technology can break down the cell walls of raspberries at low temperatures (usually -35℃ to -40℃), promoting the full dissolution of nutrients while avoiding the damage to nutrients and flavor caused by high temperatures. It can also break down large molecules in raspberries into small molecules that are easily absorbed by the human body, further enhancing the product's nutritional value and taste experience. However, currently, there is no technology that organically integrates raspberry-probiotic co-fermentation technology, ultra-high pressure HPP sterilization technology, and low-temperature freezing and cell wall disruption technology for application in the processing of raspberry milk tea.

[0007] Furthermore, existing milk tea processing techniques suffer from severe homogenization, lacking differentiated technologies with core competitiveness, making it difficult to form unique product advantages and meet the market's demand for specialty milk teas that excel in nutrition, flavor, and taste. Therefore, how to overcome the shortcomings of existing technologies and organically combine raspberry-probiotic co-fermentation technology with innovative processes such as ultra-high pressure HPP sterilization and low-temperature freezing and cell wall disruption to create a differentiated, fresh-locking, nutritious raspberry milk tea that integrates health, flavor, and taste has become a pressing technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0008] I. Technical Problems to be Solved: Existing raspberry milk tea processing technology faces numerous technical bottlenecks, making it difficult to simultaneously ensure product health, flavor integrity, smooth texture, and nutrient preservation: Traditional raspberry milk tea often involves directly adding raspberry juice or fruit pieces without scientific fermentation. This makes it difficult for the body to absorb the active nutrients in raspberries, such as polyphenols and anthocyanins, and it lacks the added health benefits of probiotics. Conventional sterilization processes (such as pasteurization and high-temperature instantaneous sterilization) easily damage heat-sensitive nutrients in raspberries, leading to nutrient loss and altering the inherent fruity aroma, resulting in a burnt or off-flavor. The dense cell wall structure of raspberry pulp cannot be effectively broken down by conventional processing methods, resulting in insufficient release of raspberry flavor, a grainy texture in the milk tea, and difficulty in fully dissolving nutrients. Furthermore, existing processes cannot achieve a synergistic optimization of health, flavor, and texture, leading to severe product homogenization and a lack of differentiated competitive advantage.

[0009] This invention aims to address the shortcomings of the existing technology by providing a method for preparing raspberry milk tea that relies on raspberry-probiotic co-fermentation technology and integrates ultra-high pressure HPP sterilization and low-temperature freezing cell wall breaking innovative processes. This method achieves a three-in-one improvement in product health, flavor, and taste, creating a differentiated, fresh-locking, and nutritious raspberry milk tea, thus filling the gap in the existing technology.

[0010] II. Technical Solution The core technical solution of this invention is as follows: relying on raspberry-probiotic co-fermentation technology, integrating ultra-high pressure HPP sterilization and low-temperature freezing cell wall breaking innovative processes, and through the synergistic cooperation of multiple processes, a differentiated, fresh-locking, and nutritious raspberry milk tea integrating health, flavor, and taste is created. The specific steps are as follows: (1) Raw material pretreatment: Select fresh, rot-free, and pest-free raspberries, remove the stems and impurities, rinse them with purified water and drain the surface water; select high-quality milk tea base that is free from spoilage and odor (milk, plant milk or compound milk base can be used) for later use; select active probiotic strains (preferably one or two of Lactobacillus pentosus and Lactobacillus plantarum, to ensure that the activity of the strains meets the food grade standards) for later use.

[0011] (2) Low-temperature freezing and cell wall breaking treatment: The pre-treated raspberries are placed in a freezing device and frozen at a low temperature of -20℃ to -40℃ for 1 to 3 hours to allow water in the raspberry pulp cells to crystallize. The expansion pressure of the ice crystals is used to break the cell wall structure of the raspberries. After freezing, the raspberries are taken out and quickly placed in a room temperature environment to thaw for 0.5 to 1 hour. The cell walls are further broken through the alternating freezing and thawing action. Then, a colloid mill is used for auxiliary grinding to obtain a fine raspberry pulp, ensuring that the nutrients in the raspberries are fully dissolved, while improving the subsequent fermentation efficiency and the smoothness of the milk tea taste, and avoiding the generation of a grainy texture.

[0012] (3) Raspberry-Probiotic Co-fermentation Treatment: The raspberry pulp after low-temperature freezing and cell wall disruption was mixed evenly with the milk tea base in a certain proportion. The pH value of the mixed system was adjusted to 4.5~6.0. A preset amount of active probiotic strains were added, and the fermentation temperature was controlled at 30℃~37℃. The fermentation time was 12~24h for co-fermentation treatment. During the fermentation process, the number of viable bacteria and the change in acidity of the system were monitored in real time to ensure that the number of viable probiotics was ≥10 at the end of fermentation. 8 With CFU / mL and acidity controlled within a suitable range, the natural fruit aroma of raspberries is fully integrated with the flavor substances produced by probiotic fermentation. At the same time, the large molecular nutrients in raspberries are degraded into easily absorbed small molecules, enhancing the health value of the product and giving it a unique fermented flavor that distinguishes it from the single fruit aroma of traditional raspberry milk tea.

[0013] (4) Ultra-high pressure HPP sterilization treatment: The co-fermented raspberry milk tea mixture is sealed and packaged, and placed in an ultra-high pressure HPP sterilization equipment. The sterilization pressure is controlled at 300~600MPa, the sterilization temperature is 5~25℃, and the holding time is 3~10min. Circulating cooling water is used to maintain a stable temperature to avoid damage to nutrients and flavor caused by high temperature. Through ultra-high pressure HPP sterilization technology, hydrostatic pressure is used to destroy the cell membrane structure and enzyme activity of microorganisms, and to completely inactivate harmful microorganisms such as coliform bacteria and Salmonella, ensuring food safety of the product. At the same time, the heat-sensitive nutrients such as polyphenols and anthocyanins in raspberries and the active substances produced by probiotic fermentation are preserved to the maximum extent, so as to achieve nutrient preservation and solve the problems of nutrient loss and flavor deterioration caused by traditional high temperature sterilization.

[0014] (5) After post-processing and sterilization of finished product, the raspberry milk tea is quickly cooled to below 4°C, aseptically filled and sealed. After passing inspection, it is stored in a cold chain environment of 2~4°C to obtain a differentiated fresh-locking nutritious raspberry milk tea product that combines health, flavor and taste.

[0015] (6) Optimization of process parameters To further improve product quality, the core process parameters were optimized: The optimal conditions for low-temperature freezing and cell wall breaking are freezing temperature -30℃, freezing time 2h, and thawing time 0.8h; The optimal conditions for raspberry-probiotic co-fermentation are raspberry pulp to milk tea base mass ratio of 1:3~1:5, probiotic inoculation amount of 0.5%~1.5%, fermentation temperature of 34℃, and fermentation time of 18h; The optimal conditions for ultra-high pressure HPP sterilization are pressure of 450MPa, temperature of 15℃, and holding time of 6min. This combination of parameters can achieve the best balance between nutrient retention, flavor presentation and taste experience.

[0016] III. Beneficial Effects Compared with existing technologies, this invention has the following significant beneficial effects: 1. Outstanding health value and nutritional upgrade: By adopting raspberry-probiotic co-fermentation technology and selecting probiotic strains suitable for raspberry fermentation, it can not only degrade macromolecular nutrients in raspberries and improve the absorption rate of nutrients, but also retain the activity of probiotics, regulate the balance of human intestinal flora, and give the product unique health added value; At the same time, through the synergistic effect of low-temperature freezing and high-pressure HPP sterilization, the heat-sensitive nutrients such as polyphenols, anthocyanins, and vitamins in raspberries are preserved to the maximum extent, solving the problem of serious nutrient loss in traditional processes and achieving a dual improvement of "nutrition + health".

[0017] 2. Unique and stable flavor, achieving differentiation: During the raspberry-probiotic co-fermentation process, the natural fruit aroma of raspberries and the flavor substances produced by probiotic fermentation are fully integrated, effectively enhancing the flavor profile of the product, reducing the sourness of raspberries, and inhibiting the generation of unpleasant odors; ultra-high pressure HPP sterilization technology avoids the destruction of flavor by high temperatures, and can stably preserve the natural fruit aroma and fermented flavor of the product for a long time, differentiating it from the single flavor of traditional raspberry milk tea and forming a differentiated competitive advantage. 3. Delicate and smooth texture, enhancing the consumer experience: The low-temperature freezing and cell wall breaking process, through alternating freeze-thaw cycles and colloid mill-assisted grinding, thoroughly breaks down the raspberry cell walls, avoiding a grainy texture in the milk tea, allowing the raspberry pulp to fully blend with the milk tea base, resulting in a delicate and smooth texture; at the same time, the co-fermentation process improves the viscosity of the milk tea, preventing layering, further enhancing the product's texture stability, and solving the problems of rough texture and easy layering in existing raspberry milk tea. 4. Excellent freshness retention and extended shelf life: Ultra-high pressure HPP sterilization technology achieves efficient sterilization under low-temperature conditions, completely inactivating harmful microorganisms while avoiding damage to nutrients and flavor. Combined with cold chain storage, the product shelf life can be extended to 30-60 days. Compared with traditional processes, the freshness retention effect is significantly improved, and there is no need to add excessive preservatives, which better meets the consumer demand for healthy food. 5. Innovative and feasible process, suitable for industrial production: This invention organically integrates three innovative processes: raspberry-probiotic co-fermentation, ultra-high pressure HPP sterilization, and low-temperature freezing and cell wall disruption. The process steps are clear, the parameters are controllable, and no complex special equipment is required. It can be adapted to existing food processing production lines, facilitating large-scale industrial production and has broad application prospects. In summary, this invention, through multi-process collaborative innovation, effectively solves the technical problems in existing raspberry milk tea processing, such as nutrient loss, monotonous flavor, rough texture, and poor freshness retention. It successfully creates a differentiated, freshness-locking, nutritious raspberry milk tea that integrates health, flavor, and taste. The process is highly innovative and practical, with significant economic value and market competitiveness. IV. Description of the attached drawings Figure 1 is a flow chart of the preparation process of raspberry milk tea co-fermented with raspberries and probiotics according to the present invention. The attached figure clearly shows the complete preparation steps of the present invention, the connection relationship between each step and the key process parameters, and intuitively demonstrates the synergistic effect of the three innovative processes of raspberry-probiotic co-fermentation, low-temperature freezing and cell wall disruption, and ultra-high pressure HPP sterilization. The following is an explanation of the figure markings: S1 - Raspberry raw material pretreatment step; S2 - Raspberry-probiotic co-fermentation step; S3 - Low-temperature freezing and cell wall disruption step; S4 - Mixing and blending step; S5 - Ultra-high pressure HPP sterilization step; S6 - Filling and refrigeration step. 2. Detailed explanation of the process in the attached diagram: (1) Step S1 (pretreatment of raspberry raw materials): The pretreatment process of raspberry raw materials in the corresponding process is clearly marked in the attached diagram as follows: "Fresh red raspberries, black raspberries → remove fruit stem impurities → gently wash with washing solution (acetic acid: sodium bicarbonate = 100:1) for 3-5 minutes → drain with sterile gauze → sterile crush to particle size of 2-3 mm → raspberry pulp". It is also marked that the temperature is controlled at 10-15℃ throughout the process, which intuitively reflects the pretreatment process and key control conditions of raspberry raw materials, ensuring that the pretreatment operation is consistent with that in Examples 1-3 (only the raspberry ratio is different, but the process is completely the same). (2) Step S2 (Raspberry-Probiotic Co-fermentation, one of the three innovative processes): The corresponding co-fermentation process is clearly marked in the attached diagram as follows: "Raspberry pulp → Add activated compound probiotics (37℃, sterile physiological saline activation for 30 min) → Aerobic primary fermentation at 32℃ for 18 h (stirring for 5 min every 6 h) → Add erythritol and fructooligosaccharides → Anaerobic secondary fermentation at 28℃ for 60 h → Raspberry-Probiotic fermentation liquid". The fermentation endpoint control indicators are also marked as follows: pH value 3.0-3.2, alcohol content <0.5%, total lactic acid bacteria count ≥1×10 6(CFU / mL); Regarding the differences between Examples 2 and 3, the accompanying drawings are marked in the form of notes: "Example 2: primary fermentation 30℃ / 20h, secondary fermentation 26℃ / 72h, pH value 3.1-3.3; Example 3: primary fermentation 35℃ / 16h, secondary fermentation 30℃ / 48h, pH value 2.9-3.1". The bolded parts above are the core details of the accompanying drawings corresponding to this innovative process, clearly showing the two-step fermentation mode of co-fermentation, key parameters and adjustment differences of different examples, ensuring complete matching with the co-fermentation parameters of the three examples, and intuitively reflecting the innovation of the process. (3) Step S3 (low-temperature freezing and cell wall breaking treatment, the second of the three innovative processes): The corresponding low-temperature freezing and cell wall breaking process is clearly marked in the attached figure as "raspberry-probiotic fermentation liquid → -70℃ freezing for 3h (gem level 7 hardness) → -80℃ supersonic airflow cell wall breaking (breakage coefficient 1000 mesh, high and low speed conversion mode) → cell wall breaking liquid (particle size ≤50μm, cell wall breaking rate ≥99%) → 10-15℃ thawing for later use"; Regarding the differences between Examples 2 and 3, the notes are marked as "Example 2: -65℃ freezing for 4h, breakage coefficient 900 mesh, particle size ≤60μm; Example 3: -75℃ freezing for 2h, breakage coefficient 1100 mesh, particle size ≤40μm". The bolded part above is the core attached figure detail corresponding to this innovative process, which fully presents the synergistic operation of low-temperature freezing and supersonic airflow cell wall breaking, key control parameters and adjustment differences of different examples, which is completely consistent with the process description, highlighting the innovation of this process in terms of nutrient retention and taste improvement. (4) Step S4 (mixing and blending): The mixing and blending process corresponds to the process in the attached diagram. It is marked "fresh milk + purified water → stir evenly at 25℃ → add raspberry-probiotic cell wall breaking liquid (stir for 15 minutes at 300 r / min) → add sodium carboxymethyl cellulose (continue stirring for 10 minutes) → raspberry milk tea initial product". It is noted that the pH value is controlled at 6.5-7.0 during the blending process. For the differences between Examples 2 and 3, it is noted that "Example 2: stirring time 12 minutes; Example 3: stirring time 18 minutes" to ensure that the blending operation and parameters are consistent with each example. (5) Step S5 (high pressure HPP sterilization treatment, the third of the three innovative processes): The HPP sterilization process corresponds to the process in the attached diagram. It is clearly marked "raspberry milk tea initial product → high pressure sterilization at 450 MPa and 22℃ for 8 minutes → rapid cooling to below 10℃ for standby", and the indicators after sterilization are marked (probiotic live bacteria count ≥ 1 × 10 5CFU / mL, total number of microorganisms ≤100CFU / mL); Regarding the differences between Examples 2 and 3, the notes are marked "Example 2: 400MPa, 20℃ sterilization for 10min; Example 3: 500MPa, 25℃ sterilization for 6min". The bolded part above is the core figure details corresponding to this innovative process, accurately presenting the key parameters, operation process and sterilization effect indicators of ultra-high pressure non-thermal sterilization, which is completely consistent with the process description, highlighting the innovation of this process in terms of freshness, liveness and nutrition. (6) Step S6 (filling and refrigeration): corresponding to the filling and refrigeration process in the process, the figure is marked "sterilized milk tea → 8-10℃ aseptic filling → sealing → 2-8℃ refrigeration → finished raspberry milk tea", which is completely consistent with the filling and refrigeration operation of Examples 1-3, clearly showing the final processing flow of the finished product. Detailed Implementation

[0018] Example 1 1.1 Raw Material Preparation (by weight) • Raspberry Raw Material: 40 parts fresh red raspberries and 20 parts fresh black raspberries. Fruits should be 80-90% ripe, free from rot, pests, and mechanical damage. Pre-treatment should be completed within 3 hours of harvesting to avoid nutrient loss. • Probiotic Strains: 0.8 parts compound probiotics, composed of *Lactobacillus reuteri* (DSM17938) and *Lactobacillus plantarum* in a 1:1 ratio, with a live bacteria count ≥10 billion CFU / g. No sucrose, flavorings, or other unnecessary additives are included. The probiotics are compatible with the human gut and resistant to low temperatures and HPP stress. • Milk Base: 50 parts fresh milk, with a fat content of 3.2-3.8% and a protein content ≥3.0%. Low-temperature pasteurization (72-75℃, 15-20s) is used to preserve the original nutrients and flavor of the milk. • Auxiliary Raw Material: 5 parts erythritol. 1 part (calorie-free, suitable for health needs), 2 parts fructooligosaccharides (prebiotic, synergistic with probiotic proliferation), 0.15 parts sodium carboxymethyl cellulose (stabilizer, improves system stability), 15 parts purified water; • Cleaning solution: acetic acid and sodium bicarbonate are mixed at a ratio of 100:1 and used for cleaning and disinfecting raspberry raw materials. 1.2 Preparation process steps Step 1: Raspberry raw material pretreatment After removing the stems and impurities from fresh red and black raspberries, place them in the cleaning solution and gently wash them for 3-5 minutes using a fruit washing machine to remove surface mud, residual pesticides, and microorganisms; after washing, drain the surface water with sterile gauze and crush them into particles of 2-3 mm in a sterile crusher to obtain raspberry pulp for later use; the temperature is controlled at 10-15℃ throughout the process to avoid oxidative browning of the raspberries. Step 2: Raspberry-Probiotic Co-fermentation. The raspberry pulp obtained in Step 1 is transferred to a sterile fermentation tank. Pre-activated compound probiotics are added (activation conditions: 37℃, sterile saline for 30 min, viable count ≥ 10 billion CFU / mL after activation). The mixture is stirred thoroughly, and the temperature inside the fermentation tank is controlled at 32℃ for aerobic primary fermentation for 18 hours. During this period, the mixture is stirred every 6 hours for 5 minutes each time to promote sufficient contact between the probiotics and the raspberry pulp. After primary fermentation, erythritol and fructooligosaccharides are added to the fermentation tank, stirred thoroughly, and the fermentation tank is sealed. The temperature is controlled at 28℃ for anaerobic secondary fermentation for 60 hours to complete the co-fermentation process, obtaining the raspberry-probiotic fermentation broth. Fermentation endpoint control: pH value stabilized at 3.0-3.2, alcohol content < 0.5%, total lactic acid bacteria count ≥ 1 × 10⁻⁶. 6The fermentation broth is uniformly purplish-red with CFU / mL, and has a rich raspberry aroma and probiotic fermentation flavor. Step 3: Low-Temperature Freezing and Cell Wall Disruption Treatment. Transfer the raspberry-probiotic fermentation broth obtained in Step 2 into a sterile freezing tank, control the freezing temperature at -70℃, and freeze for 3 hours until the fermentation broth reaches a gemstone hardness of 7. Remove the frozen fermentation broth and place it in a supersonic airflow blender for cell wall disruption at a low temperature of -80℃. Control the disruption coefficient at 1000 mesh, using a high-low speed switching mode (first at 2000 rpm for 20 seconds, gradually accelerating to 10000 rpm for 60 seconds, then at 8000 rpm for 40 seconds, and finally reducing to 6000 rpm for 30 seconds) to ensure that the raspberry cell wall disruption rate is ≥99% and the particle size of the fermentation broth after disruption is ≤50μm, resulting in a fine raspberry-probiotic cell wall disruption liquid. After disruption, thaw the disrupted liquid at 10-15℃ for later use. The entire process is carried out at low temperatures to avoid oxidation of nutrients and loss of probiotic activity. Step 4: Mixing and Blending. Add fresh milk and purified water to a sterile mixing container and stir well. Control the temperature at 25℃. Slowly add the raspberry-probiotic cell wall-breaking liquid obtained in Step 3 while stirring continuously at a speed of 300 rpm for 15 minutes. Then add sodium carboxymethyl cellulose and continue stirring for 10 minutes to ensure the system is evenly mixed without lumps or layers, thus obtaining the initial raspberry milk tea product. During the blending process, control the pH value of the system to 6.5-7.0 to ensure a smooth taste and avoid being too sour or too sweet. Step 5: High-Pressure HPP Sterilization. The raspberry milk tea initial product obtained in Step 4 is transferred to a sterile HPP sterilization tank. The sterilization pressure is controlled at 450 MPa, the holding time at 8 minutes, and the sterilization temperature is controlled at 22℃. This high-pressure, non-thermal sterilization method avoids the destruction of raspberry nutrients (such as anthocyanins and vitamin C), probiotic activity, and flavor compounds by high temperatures. After sterilization, the milk tea temperature is quickly reduced to below 10℃ for later use. Testing shows that the number of viable probiotics after sterilization is ≥1×10⁻⁶. 5CFU / mL, total microbial count ≤100 CFU / mL, meeting food hygiene standards. Step 6: Filling and Refrigeration. The sterilized raspberry milk tea from Step 5 is filled into sterile sealed containers using aseptic filling equipment under sterile conditions. The filling temperature is controlled at 8-10℃. After filling, the containers are sealed immediately to avoid secondary contamination. After sealing, the milk tea is transferred to a cold storage room and stored at a temperature of 2-8℃ to obtain the finished raspberry milk tea. 1.3 Finished Product Testing and Results The raspberry milk tea prepared in this embodiment has a uniform purplish-red color, is clear and transparent, without layering, sediment, or impurities; the taste is delicate and smooth, without a grainy texture, combining the fresh fruity aroma of raspberries, the fermented aroma of probiotics, and the creamy texture of milk, with a balanced sweet and sour taste and no bitterness; nutritionally, the anthocyanin retention rate is ≥92%, the vitamin C retention rate is ≥90%, and the number of live probiotics is ≥1×10⁻⁶. 5With a concentration of CFU / mL, it contains abundant dietary fiber and prebiotics to meet healthy nutritional needs; it has excellent freshness-locking effect, with a shelf life of up to 30 days under refrigeration conditions of 2-8℃, during which the flavor, taste and nutritional components remain largely unchanged. Compared with traditional high-temperature sterilized raspberry milk tea, the shelf life is extended by more than 15 days and the nutrient retention rate is increased by more than 30%. Example 2 2.1 Raw material preparation (by weight) • Raspberry raw material: 35 parts fresh red raspberries and 25 parts fresh black raspberries, ripeness 80-90%, pre-processed within 3 hours after harvesting; • Probiotic strain: 0.6 parts compound probiotics, composed of Lactobacillus reuteri (DSM17938) and Lactobacillus acidophilus in a 2:1 ratio, with a live bacteria count ≥10 billion CFU / g; • Milk base: 55 parts fresh milk, fat content 3.2-3.8%, protein content ≥3.0%, pasteurized at low temperature; • Auxiliary raw materials: 4 parts erythritol, 1.5 parts fructooligosaccharides, 0.12 parts sodium carboxymethyl cellulose, and 12 parts purified water; • Cleaning solution: prepared by mixing acetic acid and sodium bicarbonate in a 100:1 ratio. 2.2 Preparation Process Steps: Step 1: Raspberry raw material pretreatment, consistent with Example 1, except for the raspberry raw material ratio, to obtain raspberry pulp; Step 2: Raspberry-probiotic co-fermentation, controlling the initial fermentation temperature at 30℃ for 20h, the secondary fermentation temperature at 26℃ for 72h, the final pH value of fermentation at 3.1-3.3, other operations are consistent with Example 1, to obtain raspberry-probiotic fermentation liquid; Step 3: Low-temperature freezing and cell wall breaking treatment, freezing temperature -65℃, freezing time 4h, cell wall breaking coefficient 900 mesh, speed conversion mode consistent with Example 1, particle size ≤60μm after cell wall breaking, other operations are consistent with Example 1, to obtain raspberry-probiotic cell wall broken liquid; Step 4: Mixing and blending, adjusting the ratio of fresh milk to purified water, stirring time 12min, other operations are consistent with Example 1, to obtain the initial product of raspberry milk tea; Step 5: High-pressure HPP sterilization treatment, sterilization pressure 400MPa, holding time 10min, sterilization temperature 20℃, other operations are the same as in Example 1; Step 6: Filling and refrigeration, the same as in Example 1. 2.3 Finished Product Testing and Effects The raspberry milk tea prepared in this example has a uniform purplish-red color, a delicate and smooth taste, a harmonious blend of fruit and milk aromas, and a moderate sweet and sour flavor; anthocyanin retention rate ≥90%, vitamin C retention rate ≥88%, and probiotic live bacteria count ≥1×10 5CFU / mL; under refrigeration at 2-8℃, shelf life can reach 28 days, with no layering or sedimentation, good flavor and nutritional stability, suitable for large-scale production. Example 3 3.1 Raw material preparation (by weight) • Raspberry raw material: 45 parts fresh red raspberries, 15 parts fresh black raspberries, ripeness 80-90%, pre-treated within 3 hours after harvesting; • Probiotic strain: 1.0 part compound probiotic, composed of Lactobacillus plantarum and Lactobacillus acidophilus in a 1:1 ratio, with a viable count ≥10 billion CFU / g; • Milk base: 48 parts fresh milk, fat content 3.2-3.8%, protein content ≥3.0%, low-temperature pasteurization treatment; • Auxiliary raw materials: 6 parts erythritol, 2.5 parts fructooligosaccharides, 0.18 parts sodium carboxymethyl cellulose, 18 parts purified water; • Cleaning solution: prepared by acetic acid and sodium bicarbonate in a 100:1 ratio. 3.2 Preparation Process Steps: Step 1: Raspberry raw material pretreatment, consistent with Example 1, only the raspberry raw material ratio is different, to obtain raspberry pulp; Step 2: Raspberry-probiotic co-fermentation, controlling the initial fermentation temperature at 35℃ for 16h, the secondary fermentation temperature at 30℃ for 48h, the final pH value of fermentation endpoint is 2.9-3.1, other operations are consistent with Example 1, to obtain raspberry-probiotic fermentation liquid; Step 3: Low-temperature freezing and cell wall breaking treatment, freezing temperature -75℃, freezing time 2h, cell wall breaking coefficient 1100 mesh, speed conversion mode is consistent with Example 1, the particle size after cell wall breaking is ≤40μm, other operations are consistent with Example 1, to obtain raspberry-probiotic cell wall broken liquid; Step 4: Mixing and blending, the ratio of fresh milk to purified water is adjusted, the stirring time is 18min, other operations are consistent with Example 1, to obtain the initial product of raspberry milk tea; Step 5: Ultra-high pressure HPP Sterilization treatment: sterilization pressure 500MPa, holding time 6min, sterilization temperature 25℃, other operations are the same as in Example 1; Step 6: filling and refrigeration, the same as in Example 1. 3.3 Finished product testing and effects The raspberry milk tea prepared in this example has a rich color, prominent raspberry aroma, smooth and creamy texture, and a sweet and sour taste; anthocyanin retention rate ≥93%, vitamin C retention rate ≥91%, and probiotic live bacteria count ≥1×10 5 CFU / mL; Shelf life can reach 32 days under refrigeration at 2-8℃, with excellent nutritional components and flavor stability, suitable for the high-end health beverage market.

[0019] Key Process Notes: 1. Raspberry-Probiotic Co-fermentation Process: A compound probiotic strain suitable for raspberry fermentation is selected. Through a combination of aerobic primary fermentation and anaerobic secondary fermentation, the nutrients in raspberries are fully released, and the metabolic products generated by probiotic fermentation enhance the flavor and health value of the product. Simultaneously, fermentation parameters are controlled to avoid bitterness and nutrient loss due to over-fermentation. Fermentation conditions are optimized for the milk tea system based on existing raspberry probiotic fermentation technology to ensure good compatibility between the fermented liquid and the milk base. 2. Low-Temperature Freezing and Cell Wall Disruption Process: Ultra-low temperature freezing combined with supersonic airflow is used for cell wall disruption. Referencing blackberry seed cell wall disruption technology and adjusting parameters to suit raspberry characteristics, the raspberry cell walls are fully broken down, releasing internal anthocyanins, vitamins, and other nutrients. This avoids nutrient oxidation caused by high-temperature cell wall disruption. The particle size after disruption is controlled at 40-60μm, ensuring a smooth, particle-free texture for an enhanced drinking experience. The entire process is carried out at low temperatures to maximize the preservation of probiotic activity and the natural flavor of the raspberries. 3. Ultra-high pressure HPP sterilization process: Utilizing 400-500MPa ultra-high pressure non-thermal sterilization, replacing traditional high-temperature and high-pressure sterilization, this process effectively kills microorganisms and extends shelf life while avoiding the damage to raspberry nutrients, probiotic activity, and flavor compounds caused by high temperatures. Parameters are optimized by referencing ultra-high pressure homogenization combined with HPP sterilization to ensure sterilization effectiveness while maximizing the preservation of product nutrition and flavor, achieving the dual goals of freshness preservation and nutrition. 4. Synergistic effects: Raspberry-probiotic co-fermentation provides the product with a unique flavor and healthy nutrition; low-temperature freezing and cell wall disruption enhance nutrient release efficiency and taste; ultra-high pressure HPP sterilization locks in freshness and preserves probiotic activity. The synergistic effect of these three processes solves the technical pain points of existing raspberry milk tea, creating a differentiated, fresh-preserving, and nutritious raspberry milk tea suitable for industrial production and market promotion.

Claims

1. A fresh-locking, nutritious raspberry milk tea, characterized in that, The product is prepared by combining raspberry-probiotic co-fermentation technology, low-temperature freezing cell disruption technology and ultra-high pressure HPP sterilization technology. The preparation process includes the following steps: (1) Raspberry raw material pretreatment: Select fresh raspberries with a maturity of 80-90%, free from rot, pests and diseases, and mechanical damage. Remove the fruit stems and impurities within 3 hours after picking. Gently wash with a cleaning solution of acetic acid and sodium bicarbonate at a ratio of 100:1 for 3-5 minutes. After draining the water, crush to a particle size of 2-3 mm to obtain raspberry pulp. The operating temperature is controlled at 10-15℃ throughout the process; (2) Raspberry-probiotic co-fermentation: Transfer the raspberry pulp to a sterile fermentation tank, add activated compound probiotics, and first perform aerobic primary fermentation at 30-35℃ for 16-20 hours. Stir for 5 minutes every 6 hours during this period. Then add erythritol and fructooligosaccharides. After sealing, perform anaerobic secondary fermentation at 26-30℃ for 48-72 hours. The final pH of the fermentation is determined by the following steps: The pH value should be controlled between 2.9 and 3.3, the alcohol content should be <0.5%, and the total lactic acid bacteria count should be ≥1×10⁻⁶. 6 CFU / mL, to obtain raspberry-probiotic fermentation liquid; (3) Low temperature freezing and cell wall breaking: freeze the raspberry-probiotic fermentation liquid at -65~-75℃ for 2-4h, freeze to gem level 7 hardness, and then use a supersonic airflow cell wall breaking machine at -80℃ low temperature environment to break the cell wall, control the breaking coefficient at 900-1100 mesh, the particle size of the fermentation liquid after cell wall breaking is ≤60 μm, the cell wall breaking rate is ≥99%, and the raspberry-probiotic cell wall breaking liquid is obtained after thawing. The whole process is low temperature operation; (4) Mixing and blending: mix fresh milk that has been pasteurized at low temperature (72-75℃, 15-20s) with pure water, control the temperature at 25℃, slowly add raspberry-probiotic cell wall breaking liquid, stir at 300r / min for 12-18min, then add sodium carboxymethyl cellulose and continue stirring for 10min. After blending, the pH value of the system is 6.5-7.0, and the initial product of raspberry milk tea is obtained; (5) High-pressure HPP sterilization: The initial raspberry milk tea product is sterilized at 400-500 MPa under 20-25℃ conditions and held at pressure for 6-10 minutes. After sterilization, the temperature is rapidly reduced to below 10℃. (6) Filling and refrigeration: The product is filled into sterile sealed containers under aseptic conditions at 8-10℃. After sealing, it is refrigerated at 2-8℃ to obtain the finished raspberry milk tea.

2. The freshness-locking, nutritious raspberry milk tea according to claim 1, characterized in that, The ingredients, by weight, include: 60 parts fresh raspberries (35-45 parts red raspberries, 15-25 parts black raspberries), 0.6-1.0 parts compound probiotics, 48-55 parts fresh milk, 4-6 parts erythritol, 1.5-2.5 parts fructooligosaccharides, 0.12-0.18 parts sodium carboxymethyl cellulose, and 12-18 parts purified water.

3. The freshness-locking, nutritious raspberry milk tea according to claim 1 or 2, characterized in that, The compound probiotics are composed of two of the following: Lactobacillus reuteri (DSM17938), Lactobacillus plantarum, and Lactobacillus acidophilus, in a ratio of 1:1 or 2:1, with a live bacteria count ≥10 billion CFU / g; the probiotics are activated at 37°C with sterile physiological saline for 30 min, and the live bacteria count after activation is ≥10 billion CFU / mL.

4. The freshness-locking, nutritious raspberry milk tea according to claim 1, characterized in that, In step (3), the speed conversion mode of low-temperature freezing cell disruption is as follows: first, process at 2000 r / s for 20s, gradually accelerate to 10000 r / s for 60s, then process at 8000 r / s for 40s, and finally reduce to 6000 r / s for 30s.

5. The freshness-locking, nutritious raspberry milk tea according to claim 1, characterized in that, The fresh milk has a fat content of 3.2-3.8% and a protein content of ≥3.0%.

6. The freshness-locking, nutritious raspberry milk tea according to claim 1, characterized in that, The finished raspberry milk tea retains ≥90% of anthocyanins, ≥88% of vitamin C, and has ≥1×10⁻⁶ live probiotics. 5 CFU / mL, total microbial count ≤100 CFU / mL, shelf life ≥28 days under refrigeration conditions of 2-8℃.

7. The freshness-locking, nutritious raspberry milk tea according to claim 1, characterized in that, In step (1), a sterile crusher is used for crushing raspberries. In step (4), a sterile mixing tank is used for mixing and blending. In step (5), a sterile HPP sterilization tank is used for HPP sterilization. In step (6), a sterile filling equipment is used for filling. A sterile environment is maintained throughout the process to avoid secondary contamination.

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