A method for separating and extracting water-soluble pectin from fruit peels and a pectin drink

Abstract

The present application relates to the field of food and beverage processing and fruit by-product resource utilization, and provides a method for separating and extracting water-soluble pectin from fruit peel and a pectin beverage. The present application realizes the co-processing of fruit peel cleaning, hot washing, acid extraction, concentration and wet micro-fining of pectin extraction residues, so that water-soluble pectin covers the micro-fiber of the fruit peel to form composite particles, and the composite particles are sheared and homogenized to form a low-viscosity and suspendable beverage, thereby achieving the balance of pectin extraction efficiency, coating capacity, suspension stability and processing fluidity, solving the problem of the difficulty in unifying the pectin structure damage and stability caused by strong acid hot extraction and the fluidity, and being suitable for fruit processing by-product resource utilization and pectin functional beverage preparation.

Description

Technical Field

[0001] This invention relates to the fields of food and beverage processing and resource utilization of fruit by-products, specifically to a method for separating and extracting water-soluble pectin from fruit peels and a pectin beverage. Background Technology

[0002] The fruit processing industry continuously generates byproducts such as apple peels, apple pomace, pear peels, pear pomace, and yellow peach peels and pomace during the production of juice, canned goods, jams, and fresh-cut fruits. These raw materials typically contain pectin, polysaccharides, fiber, aromatic substances, and small amounts of organic acids. Treating them solely as low-value feed or waste is detrimental to the resource utilization of the processing chain. With increasing consumer focus on clean labels, dietary fiber supplementation, low-sugar and low-fat beverages, and natural texture systems, the preparation of drinkable, suspendable, and palatable pectin-based beverages using fruit peel byproducts has significant industrial value. Such beverages require not only pectin to maintain a certain level of water solubility and coating capacity in acidic systems, but also fine fruit peel fibers with appropriate particle size, low roughness, and good suspension dispersion. Simultaneously, the system viscosity must not be too high to avoid affecting the smoothness of blending, sterilization, filling, and drinking. Therefore, establishing a stable process window between pectin extraction, fiber micronization, and beverage blending is an important direction for the high-value application of fruit peel resources.

[0003] Existing pectin utilization technologies mostly focus on obtaining high-purity pectin from raw materials such as apple pomace and citrus peel, or adding pectin and plant fiber as thickening and stabilizing ingredients to food systems. For example, Chinese patent CN108276504A discloses a process for extracting high-purity pectin from apple pomace, involving steps such as acid extraction, decolorization, concentration, precipitation, and drying. However, its focus is on obtaining dry pectin products, and it does not establish a beverage-grade composite particle system for the simultaneous utilization of wet pectin extract and fruit peel fiber residue. Another disclosed technology uses apple fiber or citrus fiber with pectin in a plant-based beverage stabilization system, but it leans more towards pre-made fiber compositions or powder stabilizers, and does not fully address the coupling issues between pectin extraction strength, pectin coating capacity, fiber micronization degree, suspension stability, and low-viscosity processing. Stronger acid and heat conditions are beneficial for increasing pectin release, but may lead to a decrease in pectin structure and coating capacity; excessive increase in fiber micronization and pectin coating can easily increase the rheological resistance of the system, affecting beverage processing and drinking experience. Summary of the Invention

[0004] The purpose of this invention is to provide a method for separating and extracting water-soluble pectin from fruit peels and a pectin beverage, thereby solving the current pain point that it is difficult to simultaneously achieve optimal pectin extraction efficiency, pectin coating capacity, beverage suspension stability, and processing fluidity.

[0005] Strong acid-heat extraction is beneficial for pectin release, but it easily weakens the pectin coating ability; gentle extraction is difficult to balance extraction efficiency; enhancing pectin coating and fiber micronization can improve suspension, but it easily increases viscosity. This invention achieves a synergistic unity of extraction, coating, stabilization and flow by matching the ratio of pectin extract concentrate to microfiber pulp, shear homogenization and acidity control.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A pectin beverage containing water-soluble pectin extracted from fruit peel, comprising, by weight of the total mass of the pectin beverage: Pectin-coated microfiber composite particles, 0.20–1.20 wt%; Organic acids 0.02–0.25 wt%; Water used in beverage production should be replenished to 100 wt%. The pectin-coated microfiber composite particles include microfibers and water-soluble pectin extracted from the pericarp, which coats the surface of the microfibers. The water-soluble pectin extracted from the fruit peel comes from fruit peels or fruit residue produced during food processing. The fine fruit peel fibers are derived from one or more of the following: apple peel for food processing, apple pomace for food processing, fragrant pear peel for food processing, pear pomace for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing. The mass ratio of the fine pericarp fibers, on a dry basis, to the water-soluble pectin extracted from the pericarp, on a pectin solids basis, is 100:5–25.

[0007] The term "pectin solids" as used in this article refers to the solids obtained by drying and weighing the concentrated water-soluble pectin extract; in the mass ratio of the fine pericarp fibers on a dry basis to the water-soluble pectin on a pectin solids basis, the mass of the water-soluble pectin is calculated based on the mass of the pectin solids; the content of the pectin-coated fine pericarp fiber composite particles is calculated relative to the total mass of the pectin beverage as the sum of the dry basis mass of the fine pericarp fibers and the mass of the pectin solids added to the composite particle slurry.

[0008] Furthermore, the D50 of the pectin-coated microfiber composite particles is 20–80 μm, and the D90 is 80–150 μm; the pH value of the pectin beverage is 3.2–4.2.

[0009] Furthermore, the water-soluble pectin extract concentrate used to prepare the pectin beverage is prepared through the following steps: B1. Select one or more of the following as raw materials: apple peel for food processing, apple pomace for food processing, fragrant pear peel for food processing, pear pomace for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing, and crush them to 2–8 mm. B2. Mix the fruit peel raw material with beverage production water at a mass ratio of 1:4–8, and adjust the pH of the system to 2.8–3.4 using a food-grade acidity regulator; B3. Extract at 75–90℃ for 45–120 min to obtain pectin extract slurry; B4. The pectin extraction slurry is subjected to solid-liquid separation to obtain pectin extract and pectin extraction residue; B5. Concentrate the pectin extract to a pectin solids content of 1–6 wt% to obtain the water-soluble pectin extract concentrate.

[0010] Furthermore, the pH value of the water-soluble pectin extract concentrate is 2.8–4.2.

[0011] Furthermore, the fine pectin fiber slurry used to prepare the pectin beverage is prepared through the following steps: C1. Select one or more of the following as fruit peel fiber raw materials: the pectin extraction residue obtained in step B4, or the apple peel, apple pomace, pear peel, pear pomace, yellow peach peel, and yellow peach pomace that have been washed, crushed, and blanched: apple peel for food processing, apple pomace for food processing, pear peel for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing. C2. Wash the fruit peel fiber raw material with beverage production water until the pH of the washing solution is 4.0–6.0; C3. The washed fruit peel fiber raw material is formulated into a wet slurry with a solid content of 3–15 wt%; C4. The wet slurry is subjected to wet pulverization to obtain fine fruit peel fibers with a D50 of 20–80 μm and a D90 of 80–150 μm; C5. The slurry containing the fine pericarp fibers is kept at 80–95°C for 3–10 min to obtain the fine pericarp fiber slurry; C6. The solids content of the fine fruit peel fiber pulp is 3–15 wt%, and the pH value is 4.0–6.0.

[0012] Furthermore, the water-soluble pectin extracted from the fruit peel is derived from one or more of apple peel, apple pomace, pear peel, pear pomace, yellow peach peel, and yellow peach pomace; in the water-soluble pectin extract concentrate used to prepare the pectin beverage, the degree of esterification of the water-soluble pectin is 35–75%, and the galacturonic acid content is 45–80 wt% on a dry basis of pectin solids.

[0013] Furthermore, the fine fruit peel fibers include apple peel fibers derived from apple peels or apple pomace, and pear peel fibers derived from pear peels or pear pomace; the apple peel fibers account for 40–90 wt% of the dry weight of the fine fruit peel fibers, and the pear peel fibers account for 10–60 wt% of the dry weight of the fine fruit peel fibers, and the sum of the dry weight percentages of the apple peel fibers and the pear peel fibers does not exceed 100 wt%.

[0014] Furthermore, the fine pericarp fiber also includes yellow peach pericarp fiber derived from yellow peach pericarp or yellow peach pomace, wherein the yellow peach pericarp fiber accounts for 5–35 wt% of the dry weight of the fine pericarp fiber.

[0015] Furthermore, the pectin retention rate of the pectin-coated microfiber composite particles is 50–85%.

[0016] Further, the organic acid includes citric acid, L-malic acid, or both; when the organic acid includes citric acid and L-malic acid, the mass ratio of citric acid to L-malic acid is 1:1 to 5:1; the sedimentation rate of the pectin beverage after standing at room temperature for 30 days is 0.5–10 wt%, and the apparent viscosity is 5–60 mPa·s. Unless otherwise stated, the organic acid content mentioned herein refers to the percentage of the total mass of organic acid added in step S4 relative to the total mass of the pectin beverage, excluding food-grade acidity regulators used to adjust the pH value during the extraction or compounding process.

[0017] This invention employs a design that uses water-soluble pectin extracted from fruit peels to coat microfiber composite particles. This design aims to achieve a synergistic balance between suspension stability and processing flowability in beverages. Existing technologies typically enhance suspension stability by increasing fiber fineness or the amount of hydrophilic colloids, but this can easily increase system viscosity and lead to increased mixing and filling resistance. Conversely, improving processing flowability usually involves reducing colloid and fiber loads, which can exacerbate particle sedimentation and weaken mouthfeel consistency. This invention, by limiting the composite particle content, the pectin-to-microfiber mass ratio, particle size distribution, pH value, and organic acid system, allows the pectin coating layer to improve the hydration state of the fiber interface, while the microfibers provide dispersion support. Simultaneously, it avoids the flowability loss caused by simple thickening, resulting in a low-viscosity, processable pectin beverage with good suspension properties.

[0018] A method for preparing the above-mentioned pectin beverage includes the following steps: S1. Fruit peel pretreatment: Select one or more of the following as fruit peel raw materials: apple peel for food processing, apple pomace for food processing, fragrant pear peel for food processing, pear pomace for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing. Crush them to 2–8 mm and blanch them at 85–95℃ for 2–8 min to obtain pretreated fruit peel raw materials. S2. Provides a water-soluble pectin extract concentrate and a fine pericarp fiber slurry, wherein the water-soluble pectin extract concentrate is prepared from a portion of the pretreated pericarp raw material, and the fine pericarp fiber slurry is prepared from pectin extraction residue or another portion of the pretreated pericarp raw material; S3. The water-soluble pectin extract concentrate is mixed with the fine fruit peel fiber slurry. The pH of the mixture is adjusted to 3.3–4.2 using a food-grade acidity regulator. The mixture is then treated at 40–65°C with a shear speed of 3000–8000 rpm for 5–25 min and homogenized at 5–30 MPa for 1–3 passes to obtain a pectin-coated fine fruit peel fiber composite particle slurry. S4. The pectin-coated microfiber composite particle slurry is mixed with beverage production water and organic acid to obtain a formulated pectin beverage, wherein the pH value of the formulated pectin beverage is 3.2–4.2. S5. The prepared pectin beverage is sterilized and bottled to obtain the pectin beverage.

[0019] Furthermore, in step S5, the sterilization is performed at 85–95°C for 15–60 seconds, or at 110–135°C for 2–10 seconds.

[0020] Furthermore, in the pectin beverages prepared in three consecutive batches, the inter-batch coefficient of variation of the D50 of the pectin-coated micro-peel fiber composite particles was 2–10%.

[0021] Furthermore, the fruit peel raw material is washed with running water or sprayed before crushing. The washed fruit peel raw material is crushed to 2–8 mm and blanched at 85–95℃ for 2–8 min to obtain pretreated fruit peel raw material. A portion of the pretreated fruit peel raw material is mixed with beverage production water at a mass ratio of 1:4–8. The pH value of the system is adjusted to 2.8–3.4 using a food-grade acidity regulator. Extraction is carried out at 75–90℃ for 45–120 min. After solid-liquid separation, the obtained pectin extract is concentrated to a pectin solids content of 1–6 wt% to obtain a water-soluble pectin extract concentrate.

[0022] Furthermore, another portion of the pretreated fruit peel raw material or the pectin extraction residue obtained after solid-liquid separation is used as fruit peel fiber raw material. It is washed with beverage production water until the pH of the washing liquid is 4.0–6.0, and a wet slurry with a solid content of 3–15 wt% is prepared. The slurry is then wet-milled to obtain fine fruit peel fibers with a D50 of 20–80 μm and a D90 of 80–150 μm, and kept at 80–95°C for 3–10 min to obtain a fine fruit peel fiber slurry for mixing with water-soluble pectin extraction concentrate.

[0023] This invention employs a process combination of pericarp pretreatment, preparation of water-soluble pectin extract concentrate, preparation of microfiber pulp, and shearing homogenization, primarily to achieve, stabilize, or amplify the aforementioned synergistic effects. Conventional strong acid-heat extraction is beneficial for pectin release but easily weakens pectin coating capacity; simple mild extraction may reduce extraction efficiency; and while strengthening fiber pulverization alone can improve particle size, it increases rheological burden. This invention reduces raw material fluctuations through washing and blanching, prepares a water-soluble pectin extract concentrate from a portion of the pericarp, and transforms the pectin extraction residue or another portion of the pretreated pericarp into microfiber pulp. Then, under controlled pH, temperature, shear, and homogenization conditions, it promotes the formation of a stable bond between pectin and the fiber surface, ensuring that the extracted pectin does not merely exist as a free colloid but participates in the formation of composite particles. This allows for a balance between extraction efficiency, coating capacity, suspension stability, and processing flowability within the same process chain.

[0024] Water-soluble pectin extracted from fruit peels primarily improves the hydration and coating state of fine fruit peel fibers, helping to reduce roughness, sedimentation, and the risk of interfacial separation. However, increasing the amount of pectin alone or using excessively high extraction intensity can easily lead to increased system viscosity or decreased coating capacity. Fine fruit peel fibers provide a suspension framework and the basic texture of dietary fiber, but if present alone or with a large particle size, they can easily result in increased graininess and sedimentation. This invention matches the mass ratio of fine fruit peel fibers (dry basis) to water-soluble pectin (pectin solids basis), and combines acidity adjustment, shearing treatment, and homogenization treatment to mutually correct the pectin coating layer and fiber particle size. This avoids excessive thickening of free pectin and reduces sedimentation caused by exposed fibers, thus balancing suspension stability and processing flowability.

[0025] Beneficial technical effects 1. This invention separates fruit peels or fruit pomace generated during food processing for the preparation of water-soluble pectin extract concentrate and fine fruit peel fiber slurry, so that both the pectin extract and pectin extraction residue enter the beverage system, reducing the low-value treatment of fruit peel by-products and providing a raw material basis for the homologous compounding of pectin and fiber.

[0026] 2. This invention controls the size of the crushed fruit peel raw material, adjusts the pH, and controls the extraction temperature and time to release water-soluble pectin within a mild acid-heat window, reducing the adverse effects of excessive treatment on the pectin coating ability. At the same time, it controls the pectin solids content through concentration, which facilitates stable mixing with the fine fruit peel fiber pulp in the subsequent process.

[0027] 3. This invention uses a specific mass ratio of fine fruit peel fiber and water-soluble pectin to form a compound, and further controls D50, D90, shear speed and homogenization pressure to make the pectin more easily distributed on the surface of the fiber particles, reduce the rapid sedimentation caused by exposed fibers, and improve the suspension uniformity in acidic beverages.

[0028] 4. This invention achieves a balance between the content of organic acids, the ratio of citric acid to L-malic acid, the pH of the beverage, and the content of composite particles, so that the system can maintain a suitable acidity and microbial control basis, while avoiding excessive viscosity caused by simply increasing colloids, thereby improving the processing adaptability during sterilization, filling, storage, and consumption.

[0029] 5. This invention uses continuous batch particle size variation coefficient, sedimentation rate, apparent viscosity, coating rate and pectin composition indicators for quality control, so that the raw material source, particle structure and beverage performance of pectin beverages have a good correspondence, which is conducive to batch stability and quality traceability in industrial production. Attached Figure Description

[0030] Figure 1 This is a comparative graph showing the pectin retention rate and 30-day sedimentation rate of Example 1, Comparative Example 9, and Comparative Example 11.

[0031] Figure 2 The above is a scatter plot showing the coupling of 30-day sedimentation rate and apparent viscosity for Example 1 and several comparative examples.

[0032] Figure 3 The viscosity-shear rate curves of pectin beverages in Example 1 and several comparative examples are shown.

[0033] Figure 4 The sedimentation rate-time curves of pectin beverages in Example 1 and several comparative examples are shown.

[0034] Figure 5 The graph shows the effect of the pectin-coated microfiber composite particle content on the 30-day sedimentation rate and apparent viscosity under the basic formulation conditions of Example 1.

[0035] Figure 6 This is a comparison of macroscopic optical photographs of the final product of Example 1 and the final product of Comparative Example 11; wherein, Figure 6 Figure a in the image is a macroscopic optical photograph of the final acidic pectin beverage from Example 1; Figure 6 Figure b in the figure is a macroscopic optical photograph of the final product of Comparative Example 11.

[0036] Figure 7 The images show a comparison of the SEM morphology and SEM-EDS surface scan of the final product of Example 1 and the final product of Comparative Example 11; wherein, Figure 7 Figure a in the image is a low-magnification SEM image of the final product of Example 1; Figure 7 Figure b in the image is a low-magnification SEM image of the final product of Comparative Example 11; Figure 7 Figure c in the image is a medium-magnification SEM image of the final product of Example 1; Figure 7 The d-image in the image is a medium-magnification SEM image of the final product of Comparative Example 11; Figure 7 Figure e in the image is a high-magnification SEM image of the final product of Example 1; Figure 7 Figure f in the image is a high-magnification SEM image of the final product of Comparative Example 11; Figure 7 Figure g in the figure is a SEM-EDS surface scan distribution map of the final product of Example 1; Figure 7 The h-figure in the figure is a SEM-EDS surface scan distribution of the final product of Comparative Example 11. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0038] Unless otherwise stated, "standing at room temperature" as used herein refers to standing at 25°C. The term "pectin retention rate" as used herein is calculated as the percentage of pectin retained in the precipitate after centrifugation and washing relative to the total amount of pectin in the sample before centrifugation and washing. For samples containing both water-soluble pectin extract concentrate and fine pericarp fiber slurry, the pectin retention rate characterizes the degree of pectin retention and coating on the fine pericarp fiber particles, and is referred to as the pectin retention-coating rate. For comparative samples not containing water-soluble pectin extract concentrate or not containing fine pericarp fiber slurry, the pectin retention rate characterizes the degree of pectin retention in the corresponding particulate phase.

[0039] Example 1 In this embodiment, the preparation scale is 100kg of pectin beverage, and the product form is an acidic ready-to-drink pectin beverage. The raw materials are apple peel and pear peel for food processing, both of which are fresh food processing by-products, and are used after removing visible impurities; the purity of food-grade citric acid and food-grade L-malic acid are not less than 99.0%, and they are commercially available; the water used in beverage production meets the requirements for beverage processing water.

[0040] Step 1: Fruit peel pretreatment Apple peels and pear peels (for food processing) were used as raw materials, with a dry weight ratio of 40:60. The peels were washed with running water for 3 minutes, drained, and then crushed to 2mm. They were then blanched in beverage production water at 85℃ for 2 minutes, followed by rapid draining to obtain pre-treated peel raw materials. The treatment endpoint was determined by the absence of large, hard pieces of peel that could be evenly dispersed.

[0041] Step 2: Preparation of water-soluble pectin extract concentrate A portion of the pretreated fruit peel raw material was mixed with beverage production water at a mass ratio of 1:4. The pH of the system was adjusted to 2.8 using food-grade citric acid. Extraction was carried out at 75℃ with mechanical stirring for 45 minutes at a stirring speed of 300 rpm under normal atmospheric pressure. After extraction, the mixture was pre-filtered through a 100-mesh sieve and then centrifuged at 3000 rpm for 10 minutes to separate the solids and liquids, obtaining pectin extract and pectin extraction residue. The pectin extract was concentrated at 55℃ and a vacuum of 0.07 MPa until the pectin solids content was 1 wt%, and the pH was adjusted to 2.8 to obtain a water-soluble pectin extract concentrate.

[0042] Step 3: Preparation of fine fruit peel fiber pulp The pectin extraction residue obtained in step two was used as the fruit peel fiber raw material and washed with beverage production water until the pH of the washing solution reached 4.0. The washed fruit peel fiber raw material was prepared into a wet slurry with a solid content of 3 wt%, and then subjected to wet milling treatment. The temperature of the milling chamber was controlled at 25℃, and the slurry was circulated for 20 minutes to make the fine fruit peel fibers have a D50 of 20 μm and a D90 of 80 μm. Subsequently, the slurry containing the fine fruit peel fibers was kept at 80℃ for 3 minutes to obtain a fine fruit peel fiber slurry with a solid content of 3 wt% and a pH of 4.0.

[0043] Step 4: Mixing the compound granular slurry with pectin beverage Weigh 0.190 kg of dry fine pericarp fiber, corresponding to 6.35 kg of fine pericarp fiber slurry with a solid content of 3 wt%; weigh 0.0095 kg of water-soluble pectin solids, corresponding to 0.95 kg of water-soluble pectin extract concentrate with a pectin solids content of 1 wt%, so that the mass ratio of fine pericarp fiber (dry basis) to water-soluble pectin (pectin solids) is 100:5. After mixing the two, adjust the pH to 3.3 using food-grade citric acid and food-grade L-malic acid, shear at 3000 rpm for 5 min at 40℃, and homogenize once at 5 MPa to obtain pectin-coated fine pericarp fiber composite particle slurry. The slurry was mixed with beverage production water, and 0.010 kg of food-grade citric acid and 0.010 kg of food-grade L-malic acid were added. The beverage production water was then added to a total of 100 kg to obtain the prepared pectin beverage. The pectin-coated microfiber composite particles had a content of 0.20 wt%, the organic acid content was 0.02 wt%, and the pH value of the pectin beverage was 3.2.

[0044] Step 5: Sterilization and Filling The prepared pectin beverage was heated to 85℃ and held for 60 seconds, then hot-filled and sealed under clean conditions. A plate heat exchanger was used during the heating process, with outlet temperature fluctuations controlled within ±1℃. Before filling, the material was continuously and slowly stirred at 80 rpm to prevent stratification during settling.

[0045] Quality testing methods and results The particle size of the composite particles was determined using laser diffraction particle size analysis. The sample was diluted 10 times with beverage production water and stirred at low speed for 30 s. The volumetric particle size distribution was recorded, and the D50 was found to be 20 μm and the D90 to be 80 μm. The pectin retention rate was calculated by measuring the amount of free pectin in the wash liquid after centrifugation and washing, and the result was 50%. A rotational viscometer was used at 25℃ and a shear rate of 50 s⁻¹. -1 The apparent viscosity was measured to be 5 mPa·s under the given conditions; the sedimentation rate was measured to be 10 wt% after standing at room temperature for 30 days; the inter-batch coefficient of variation of D50 for three consecutive batches of samples was 10%. Each batch was measured in triplicate, and the average value was recorded.

[0046] Features and application scenarios of this embodiment This embodiment adopts a relatively conservative low-ratio scheme and mild acid-heat extraction and shear homogenization conditions. The content of composite particles, organic acid content and process intensity are all in the low value range, which is suitable for the basic preparation of low viscosity and refreshing pectin beverages, and can demonstrate the processability and smooth drinking under low particle load conditions.

[0047] Example 2 Raw materials and product scale: The product is prepared for 100 kg of acidic pectin beverage. The fruit peel raw materials used are apple pomace and pear pomace (for food processing), with a dry weight ratio of 90:10. Food-grade citric acid, food-grade L-malic acid, and water used in beverage production are all commercially available or readily available raw materials. The acidity regulator meets the requirements for use in food processing.

[0048] Pretreatment of fruit peels and acquisition of extract: Apple pomace and pear pomace for food processing were washed with running water for 4 minutes, crushed to 8 mm, and blanched at 95℃ for 8 minutes to obtain pretreated fruit peel raw materials. A portion of these raw materials was mixed with beverage production water at a mass ratio of 1:8. The pH was adjusted to 3.4 using a food-grade acidity regulator, and extraction was carried out at 90℃ for 120 minutes with a stirring speed of 500 rpm under normal atmospheric pressure. After sieving and centrifugation to separate the solids and liquids, the pectin extract was concentrated at 60℃ and a vacuum of 0.08 MPa to a pectin solids content of 6 wt%, and the pH was adjusted to 4.2 to obtain a water-soluble pectin extract concentrate.

[0049] Preparation of fruit peel fiber pulp: The pectin extraction residue after solid-liquid separation was used as the fruit peel fiber raw material and washed with beverage production water until the pH of the washing solution reached 6.0. The washed fruit peel fiber raw material was prepared into a wet pulp with a solid content of 15 wt%, and wet pulverization was performed to make the fine fruit peel fibers D50 80 μm and D90 150 μm. After pulverization, the pulp was kept at 95℃ for 10 min to obtain fine fruit peel fiber pulp with a solid content of 15 wt% and a pH of 6.0.

[0050] Construction of composite granular slurry: Weigh 0.960 kg of dry fine pectin fiber, corresponding to 6.40 kg of fine pectin fiber slurry with a solid content of 15 wt%; weigh 0.240 kg of water-soluble pectin solids, corresponding to 4.00 kg of water-soluble pectin extract concentrate with a pectin solids content of 6 wt%, so that the mass ratio of fine pectin fiber (dry basis) to water-soluble pectin (pectin solids) is 100:25. Mix the fine pectin fiber slurry and the water-soluble pectin extract concentrate, adjust the pH to 4.2 using a food-grade acidity regulator, shear at 8000 rpm for 25 min at 65℃, and homogenize three times at 30 MPa to obtain pectin-coated fine pectin fiber composite granular slurry.

[0051] Beverage preparation, sterilization, and bottling: The composite granular slurry is added to a mixing tank, along with 0.208 kg of food-grade citric acid and 0.042 kg of food-grade L-malic acid (in a 5:1 mass ratio). Beverage production water is then added to bring the total volume to 100 kg, yielding the prepared pectin beverage. The pectin-coated microfiber composite granules contain 1.20 wt% of pectin and 0.25 wt% of organic acids, with a pH of 4.2. The prepared pectin beverage is then treated at 95°C for 15 seconds, followed by bottling and sealing.

[0052] Quality testing methods and results: Laser diffraction particle size analysis was used to determine the composite particles' D50 to be 80 μm and D90 to be 150 μm; the pectin retention and coating rate was calculated to be 85% based on centrifugation washing and pectin quantification; the degree of esterification of water-soluble pectin in the water-soluble pectin extract concentrate was 75%, and the galacturonic acid content was 80 wt% on a dry basis of pectin solids; the sedimentation rate of the pectin beverage after standing at room temperature for 30 days was 0.5 wt%, at 25℃ and a shear rate of 50 s. -1 The apparent viscosity under the given conditions was 60 mPa·s; the inter-batch coefficient of variation (D50) for three consecutive batches of prepared samples was 2%. All measurements were performed in triplicate.

[0053] The features of this embodiment are as follows: This embodiment adopts an optimized scheme with a relatively high load, and the composite particle content, pectin solids ratio, shear speed and homogenization pressure are all in the high value range. It is suitable for the production of pectin beverages that emphasize suspension stability and particle coating integrity, and is applicable to continuous blending and short-time heat treatment scenarios of high solids systems.

[0054] Example 3 This embodiment uses apple peel, pear peel, and yellow peach peel (for food processing) as raw materials, with dry basis weight percentages of 60wt%, 35wt%, and 5wt%, respectively. The production scale is 100kg of pectin beverage, and the target product is a composite pectin beverage containing yellow peach peel fiber. The purity of food-grade L-malic acid is not less than 99.0%, and the water used for beverage production is pre-filtered.

[0055] The preparation process begins with pretreatment of the fruit peels. Three types of fruit peels were spray-washed for 5 minutes, crushed to 5 mm, and blanched at 90℃ for 5 minutes to obtain pretreated peel raw materials. A portion of the pretreated peel raw materials was mixed with beverage production water at a mass ratio of 1:6. The pH of the system was adjusted to 3.1 using a food-grade acidity regulator. Extraction was carried out at 82℃ for 75 minutes with a stirring speed of 400 rpm under normal atmospheric pressure. After extraction, solid-liquid separation was performed. The pectin extract was concentrated at 58℃ and a vacuum of 0.075 MPa to a pectin solids content of 3.5 wt%, and the pH was adjusted to 3.5 to obtain a water-soluble pectin extract concentrate.

[0056] Subsequently, a fine fruit peel fiber slurry was prepared. The pectin extraction residue obtained from solid-liquid separation was mixed with another portion of pretreated fruit peel raw material as the fruit peel fiber raw material. The mixture was washed with beverage production water until the pH of the washing solution reached 5.0. The washed fruit peel fiber raw material was formulated into a wet slurry with a solid content of 9 wt%. It was then wet-milled until the fine fruit peel fibers had a D50 of 50 μm and a D90 of 110 μm, and then maintained at 88℃ for 6 min to obtain the fine fruit peel fiber slurry with a solid content of 9 wt% and a pH of 5.0.

[0057] The composite granular slurry was formed as follows: 0.609 kg of dry fine pectin fiber was weighed, corresponding to 6.77 kg of fine pectin fiber slurry with a solids content of 9 wt%; 0.091 kg of water-soluble pectin solids was weighed, corresponding to 2.60 kg of water-soluble pectin extract concentrate with a pectin solids content of 3.5 wt%, so that the mass ratio of fine pectin fiber (dry basis) to water-soluble pectin (pectin solids) was 100:15. The two were mixed, and the pH was adjusted to 3.8 using a food-grade acidity regulator. The mixture was sheared at 5500 rpm for 15 min at 55°C, and homogenized twice at 18 MPa to obtain the pectin-coated fine pectin fiber composite granular slurry.

[0058] The composite granule slurry was mixed with beverage production water, and 0.120 kg of food-grade L-malic acid was added. Beverage production water was then added to bring the total volume to 100 kg. The resulting pectin beverage contained 0.70 wt% pectin-coated microfiber composite particles, 0.12 wt% organic acids, and had a pH of 3.7. The resulting pectin beverage was treated at 110°C for 10 seconds, followed by aseptic filling and sealing.

[0059] The quality testing methods and results showed that the composite particles had a D50 of 50 μm and a D90 of 110 μm, a pectin retention and coating rate of 68%, a degree of esterification of water-soluble pectin in the water-soluble pectin extract concentrate of 55%, and a galacturonic acid content of 62 wt% on a dry basis of pectin solids. The sedimentation rate of the pectin beverage after standing at room temperature for 30 days was 3.8 wt%, and the sedimentation rate at 25℃ and a shear rate of 50 s⁻¹ was [not specified]. -1 The apparent viscosity under the given conditions was 24 mPa·s; the inter-batch coefficient of variation (D50) for three consecutive batches of samples was 5.5%. Each test was performed in triplicate, and the samples were slowly inverted and mixed five times before testing.

[0060] Applicable Scenarios of This Embodiment This embodiment introduces a small amount of yellow peach peel fiber and uses medium particle load, medium pectin coating ratio and medium shear homogenization strength, making it suitable for pectin beverage preparation scenarios with milder flavor, blended peel sources and a wide processing window.

[0061] Example 4 I. Preparation Object and Raw Material State: Taking 100kg of pectin beverage as the preparation object, the fruit peel raw materials consisted of apple pomace, pear pomace, and yellow peach pomace for food processing, with dry basis mass percentages of 40wt%, 25wt%, and 35wt%, respectively. After manual removal of visible foreign matter, the raw materials were washed with running water. Food-grade citric acid, food-grade L-malic acid, and beverage production water were all commercially available food processing raw materials.

[0062] II. Fruit Peel Pretreatment and Preparation of Water-Soluble Pectin Extract Concentrate: Fruit peel raw materials were crushed to 6mm and blanched at 92℃ for 6 minutes to obtain pretreated peel raw materials. A portion of the pretreated peel raw materials was mixed with beverage production water at a mass ratio of 1:5. The pH of the system was adjusted to 3.2 using a food-grade acidity regulator, and extraction was carried out at 88℃ for 100 minutes with a stirring speed of 450 rpm. The pectin extract was then subjected to solid-liquid separation. The pectin extract was concentrated at 60℃ under a vacuum of 0.08 MPa until the pectin solids content was 5wt%, and the pH was adjusted to 3.8 to obtain the water-soluble pectin extract concentrate. The degree of esterification of the obtained water-soluble pectin was 65%, and the galacturonic acid content was 70wt% on a dry basis of pectin solids.

[0063] III. Preparation of Fine Fruit Peel Fiber Slurry: Another portion of the pretreated fruit peel raw material was mixed with the pectin extraction residue after solid-liquid separation as fruit peel fiber raw material, and washed with beverage production water until the pH of the washing solution reached 5.5. The washed fruit peel fiber raw material was prepared into a wet slurry with a solid content of 12 wt%, and wet-milled to achieve a D50 of 65 μm and a D90 of 130 μm for the fine fruit peel fibers. Subsequently, the slurry containing the fine fruit peel fibers was kept at 92℃ for 8 min to obtain the fine fruit peel fiber slurry with a solid content of 12 wt% and a pH of 5.5.

[0064] IV. Preparation of Composite Granular Slurry and Beverage: Weigh 0.833 kg of dry fine pectin fiber, corresponding to 6.94 kg of fine pectin fiber slurry with a solid content of 12 wt%; weigh 0.167 kg of water-soluble pectin solids, corresponding to 3.34 kg of water-soluble pectin extract concentrate with a pectin solids content of 5 wt%, so that the mass ratio of fine pectin fiber (dry basis) to water-soluble pectin (pectin solids) is 100:20. After mixing the two, adjust the pH to 4.0, shear at 7000 rpm for 20 min at 60℃, and homogenize twice at 25 MPa to obtain pectin-coated fine pectin fiber composite granular slurry. Add the slurry, 0.135 kg of food-grade citric acid, 0.045 kg of food-grade L-malic acid, and beverage production water to a mixing tank, bringing the beverage production water to 100 kg to obtain a pectin beverage. The pectin-coated microfiber composite particles contain 1.00 wt%, the organic acid content is 0.18 wt%, the mass ratio of citric acid to L-malic acid is 3:1, and the pH value of the pectin beverage is 3.9.

[0065] V. Sterilization, Filling, and Quality Control: The prepared pectin beverage was treated at 135℃ for 2 seconds, followed by aseptic filling. Laser diffraction particle size analysis determined the composite particle size to be 65μm and 130μm. Centrifugal washing combined with quantitative calculation of pectin yielded a pectin retention rate of 76%. The sedimentation rate of the pectin beverage after standing at room temperature for 30 days was 2.2wt%, at 25℃ and a shear rate of 50s. -1 The apparent viscosity under the given conditions was 42 mPa·s; the inter-batch coefficient of variation (D50) for three consecutive batches of prepared samples was 3.2%. Each quality test was performed in triplicate, and the samples were equilibrated at 25°C for 30 min before testing.

[0066] The process features and application directions of this embodiment This embodiment uses a combination of high yellow peach peel fiber ratio, medium-high particle load, and strong shear homogenization, which is suitable for the production of pectin beverages with abundant peel sources, high flavor complexity, and the need to balance suspension state and filling adaptability.

[0067] Comparative Example 1 The procedure was essentially the same as in Example 1, except that the content of pectin-coated microfiber composite particles was adjusted to 0.10 wt%, while other conditions remained the same: total preparation scale 100 kg, organic acid content 0.02 wt%, mass ratio of microfiber (dry basis) to water-soluble pectin (pectin solids) 100:5, pectin beverage pH 3.2, pectin raw material crushed to 2 mm, blanched at 85°C for 2 min, pectin extraction pH 2.8, extraction at 75°C for 45 min, water-soluble pectin extract concentrate pectin solids content 1 wt%, microfiber slurry solids content 3 wt%, composite treatment pH 3.3, shearing at 3000 rpm at 40°C for 5 min, homogenization at 5 MPa once, and sterilization at 85°C for 60 s.

[0068] Comparative Example 2 The process is basically the same as in Example 1, except that the organic acid content is adjusted to 0.30 wt%, including 0.150 kg of food-grade citric acid and 0.150 kg of food-grade L-malic acid. Other conditions are maintained as follows: total preparation scale 100 kg, pectin-coated microfiber composite particle content 0.20 wt%, microfiber on a dry basis and water-soluble pectin on a pectin solids basis mass ratio 100:5, pectin raw material crushed to 2 mm, blanched at 85°C for 2 min, pectin extraction pH 2.8, extraction at 75°C for 45 min, water-soluble pectin extract concentrate pectin solids content 1 wt%, microfiber slurry solids content 3 wt%, composite treatment pH 3.3, shearing at 3000 rpm at 40°C for 5 min, homogenization at 5 MPa for 1 pass, and sterilization at 85°C for 60 s.

[0069] Comparative Example 3 The procedure was essentially the same as in Example 1, except that the mass ratio of fine pericarp fibers (dry basis) to water-soluble pectin (pectin solids) was adjusted to 100:2. Other conditions remained the same: total preparation scale 100 kg, pectin-coated fine pericarp fiber composite particle content 0.20 wt%, organic acid content 0.02 wt%, food-grade citric acid to food-grade L-malic acid mass ratio 1:1, pectin beverage pH 3.2, pericarp raw material crushed to 2 mm, blanched at 85°C for 2 min, pectin extraction pH 2.8, extraction at 75°C for 45 min, water-soluble pectin extract concentrate pectin solids content 1 wt%, fine pericarp fiber slurry solids content 3 wt%, sheared at 3000 rpm at 40°C for 5 min, homogenized at 5 MPa once, and sterilized at 85°C for 60 s.

[0070] Comparative Example 4 The process was basically the same as in Example 1, except that the wet pulverization endpoint was adjusted to have a D50 of 100 μm and a D90 of 190 μm for the fine pericarp fibers. Other conditions were kept the same: total preparation scale of 100 kg, pectin-coated fine pericarp fiber composite particle content of 0.20 wt%, organic acid content of 0.02 wt%, mass ratio of fine pericarp fibers (dry basis) to water-soluble pectin (pectin solids) of 100:5, pericarp raw material crushed to 2 mm, blanched at 85°C for 2 min, pectin extraction pH of 2.8, extraction at 75°C for 45 min, pectin solids content of water-soluble pectin extract concentrate of 1 wt%, solids content of fine pericarp fiber slurry of 3 wt%, composite treatment pH of 3.3, shearing at 3000 rpm at 40°C for 5 min, homogenization at 5 MPa for 1 pass, and sterilization at 85°C for 60 s.

[0071] Comparative Example 5 The preparation method is basically the same as in Example 1, except that the pH value of the extraction system during the preparation of the water-soluble pectin extract concentrate is adjusted to 2.4, while other conditions are maintained as follows: total preparation scale 100kg, pectin-coated microfiber composite particle content 0.20wt%, organic acid content 0.02wt%, the mass ratio of microfiber on a dry basis to water-soluble pectin on a pectin solids basis 100:5, the pectin raw material is crushed to 2mm, blanched at 85℃ for 2min, extracted at 75℃ for 45min, the pectin solids content of the water-soluble pectin extract concentrate is 1wt%, the solids content of the microfiber pulp is 3wt%, the pH value of the composite treatment is 3.3, sheared at 3000rpm at 40℃ for 5min, homogenized at 5MPa once, and sterilized at 85℃ for 60s.

[0072] Comparative Example 6 The preparation method is basically the same as in Example 1, except that the extraction temperature for the water-soluble pectin extract concentrate is adjusted to 70°C, while other conditions remain the same: total preparation scale 100kg, pectin-coated microfiber composite particle content 0.20wt%, organic acid content 0.02wt%, microfiber on a dry basis and water-soluble pectin on a pectin solids basis mass ratio 100:5, pectin raw material crushed to 2mm, blanched at 85°C for 2min, pectin extraction pH 2.8, extraction for 45min, water-soluble pectin extract concentrate pectin solids content 1wt%, microfiber pulp solids content 3wt%, composite treatment pH 3.3, sheared at 3000rpm for 5min at 40°C, homogenized once at 5MPa, and sterilized at 85°C for 60s.

[0073] Comparative Example 7 The procedure is basically the same as in Example 1, except that the shearing speed in step S3 is adjusted to 1500 rpm, while other conditions remain the same: total preparation scale 100 kg, pectin-coated microfiber composite particle content 0.20 wt%, organic acid content 0.02 wt%, the mass ratio of microfiber on a dry basis to water-soluble pectin on a pectin solids basis 100:5, pectin beverage pH 3.2, pectin raw material crushed to 2 mm, blanched at 85°C for 2 min, pectin extraction pH 2.8, extraction at 75°C for 45 min, water-soluble pectin extract concentrate pectin solids content 1 wt%, microfiber slurry solids content 3 wt%, shearing at 40°C for 5 min, homogenization at 5 MPa once, and sterilization at 85°C for 60 s.

[0074] Comparative Example 8 The procedure is basically the same as in Example 1, except that the homogenization pressure in step S3 is adjusted to 2 MPa, while other conditions remain the same: total preparation scale 100 kg, pectin-coated microfiber composite particle content 0.20 wt%, organic acid content 0.02 wt%, microfiber on a dry basis and water-soluble pectin on a pectin solids basis mass ratio 100:5, pectin beverage pH 3.2, pectin raw material crushed to 2 mm, blanched at 85°C for 2 min, pectin extraction pH 2.8, extraction at 75°C for 45 min, water-soluble pectin extract concentrate pectin solids content 1 wt%, microfiber slurry solids content 3 wt%, composite treatment pH 3.3, shearing at 3000 rpm at 40°C for 5 min, homogenization once, sterilization at 85°C for 60 s.

[0075] Comparative Example 9 The procedure was essentially the same as in Example 1, except that water-soluble pectin extract concentrate was not added in step S3. Instead, an equal amount of beverage production water was added based on the mass of water-soluble pectin extract concentrate used in Example 1. Only the fine pericarp fiber slurry was sheared and homogenized. Other conditions were maintained as follows: total preparation scale 100 kg, dry basis amount of fine pericarp fiber 0.190 kg, organic acid content 0.02 wt%, pH of pectin beverage 3.2, pericarp raw material crushed to 2 mm, blanched at 85°C for 2 min, solids content of fine pericarp fiber slurry 3 wt%, pH of composite treatment 3.3, shearing at 3000 rpm for 5 min at 40°C, homogenization at 5 MPa once, and sterilization at 85°C for 60 s. This comparative example was used to investigate the synergistic relationship between water-soluble pectin and fine pericarp fiber extracted from pericarp.

[0076] Comparative Example 10 The procedure was essentially the same as in Example 1, except that fine pectin fiber slurry was not added in step S3. Instead, an equal amount of beverage production water was added based on the mass of the fine pectin fiber slurry used in Example 1. Only water-soluble pectin extract concentrate was added, followed by shearing and homogenization. Other conditions remained the same: total preparation scale 100 kg, water-soluble pectin solids 0.0095 kg, organic acid content 0.02 wt%, pectin beverage pH 3.2, pectin raw material crushed to 2 mm, blanched at 85°C for 2 min, pectin extraction pH 2.8, extraction at 75°C for 45 min, water-soluble pectin extract concentrate pectin solids content 1 wt%, composite treatment pH 3.3, shearing at 3000 rpm for 5 min at 40°C, homogenization at 5 MPa once, and sterilization at 85°C for 60 s. This comparative example was used to investigate the synergistic relationship between water-soluble pectin and fine pectin fiber extracted from pectin.

[0077] Comparative Example 11 Similar to Example 1, except that the high-speed shearing and homogenization process in step S3 was omitted. The water-soluble pectin extract concentrate and the fine pericarp fiber slurry were directly mixed at 300 rpm for 5 minutes at 40°C and then directly entered the preparation step. Other conditions were maintained as follows: total preparation scale 100 kg, pectin-coated fine pericarp fiber composite particle content 0.20 wt%, organic acid content 0.02 wt%, mass ratio of fine pericarp fiber (dry basis) to water-soluble pectin (pectin solids) 100:5, pectin beverage pH 3.2, pericarp raw material crushed to 2 mm, blanched at 85°C for 2 minutes, pectin extraction pH 2.8, extraction at 75°C for 45 minutes, water-soluble pectin extract concentrate pectin solids content 1 wt%, fine pericarp fiber slurry solids content 3 wt%, sterilized at 85°C for 60 seconds. This comparative example was used to investigate the synergistic relationship between shearing and homogenization in forming the pectin-coated fine pericarp fiber composite state.

[0078] Characterization and performance testing Using the water-soluble pectin extract concentrates from each embodiment and comparative example as test objects, the pectin solids recovery rate, degree of esterification, and galacturonic acid content were evaluated to determine the impact of extraction conditions on the basic pectin release and coating capacity. Solids were determined by drying and weighing. The degree of esterification and galacturonic acid content were calculated using titration and colorimetric methods, referring to the calculation methods for galacturonic acid and degree of esterification in the JECFA pectin specifications, with n≥3. The pectin solids recovery rate, degree of esterification, and galacturonic acid content were obtained experimentally, in percentages (%), % (%), and wt%, respectively. The pectin solids recovery rate was calculated as the percentage of the obtained pectin solids mass relative to the total pectin solids mass of the fruit peel raw material used for extraction.

[0079] Using pectin-coated fine pectin fiber composite granules and finished pectin beverages as test objects, this study evaluated D50, D90, and particle size distribution width to determine the control of particle size by wet grinding, shearing, and homogenization. Samples were diluted 10 times with beverage production water, stirred at low speed for 30 seconds, and then measured using a laser diffraction particle size analyzer. The refractive index parameter was set according to the pectin fiber aqueous dispersion system, with n≥3. The mean D50, standard deviation D50, mean D90, and standard deviation D90 were obtained, in μm. For comparative examples containing different amounts of water-soluble pectin extract concentrate and fine pectin fiber slurry, the measured D50 and D90 values ​​represent the particle size data of the corresponding dispersed particles and are only used to compare the effects of shearing, homogenization, or component absence on particle dispersion.

[0080] Using composite granular slurry as the test object, the pectin retention and coating rate was evaluated to determine the degree of binding between water-soluble pectin and fine pericarp fibers. A quantitative amount of slurry was centrifuged at 3000 rpm for 10 min. After discarding the supernatant, the sample was washed twice with beverage production water. The free pectin in the washing liquid and the retained pectin in the precipitate were measured separately. The pectin retention rate was calculated as the percentage of the total pectin in the sample before centrifugation and washing, based on the total amount of pectin in the sample before centrifugation and washing. For samples containing both water-soluble pectin extract concentrate and fine pericarp fiber slurry, this pectin retention rate was recorded as the pectin retention and coating rate. For n≥3, the mean and standard deviation of the pectin retention and coating rate were obtained, in percentages (%).

[0081] Using packaged pectin beverages as the test object, this study evaluated the sedimentation rate after standing at room temperature for 30 days to determine the contribution of the composite particle system to suspension stability. Samples were filled into transparent graduated cylinders or bottles and left to stand at 25°C for 30 days. The mass of the sedimentation layer and the total sample mass were recorded. The sedimentation rate was calculated as the percentage of the sedimentation layer mass to the total mass. Three bottles were used per group, and the mean and standard deviation of the sedimentation rate over 30 days were recorded in wt%. Lower values ​​indicate more stable suspension.

[0082] Using pectin beverages before and after bottling as test subjects, the apparent viscosity and processing flowability were evaluated to determine whether the improved stability was accompanied by excessively high flow resistance. Samples were equilibrated at 25℃ for 30 min, and then subjected to a rheometer at a shear rate of 50 s⁻¹. -1 The apparent viscosity was measured, and the outflow time of 100 mL of sample through the standard outlet was recorded simultaneously. n≥3. The recorded fields are the mean apparent viscosity, the standard deviation of apparent viscosity, the mean and standard deviation of outflow time, and the units are mPa·s and s.

[0083] Using sterilized pectin beverages as the test subject, this study evaluated pH value and microbial detection status to determine the effects of organic acids and sterilization conditions on sample pH value and total bacterial count. pH was determined using the glass electrode method, calibrated with pH 4.00 and pH 6.86 buffer solutions before testing, and recorded after the readings stabilized at 25℃. Total bacterial count was determined according to the plate count method for food microorganisms, with GB 4789.2—2022 publishing the standard for the determination of total bacterial count in food microbiology testing, n≥3. The pH value and total bacterial count were obtained, expressed as dimensionless and CFU / mL.

[0084] In the pectin beverages prepared in three consecutive batches, the inter-batch coefficient of variation of D50 was calculated by dividing the standard deviation of the average D50 of each batch of samples by the average of the average D50 of each batch of samples and multiplying by 100%; the D50 of each batch of samples was measured in parallel three times.

[0085] To verify that the method described in this invention for separating and extracting water-soluble pectin from fruit peel and preparing pectin beverages achieves a synergistic balance between pectin release, pectin coating, suspension stability, and beverage flowability, comparative tests were conducted on the pectin retention and coating rate, 30-day sedimentation rate, apparent viscosity, shear rheological behavior, influence of composite particle content, macroscopic dispersion state, microscopic morphology, and elemental distribution of Example 1 and related comparative examples. The test results show that this invention does not simply rely on increasing viscosity or enhancing the intensity of acid-heat extraction to improve system stability. Instead, it achieves good suspension stability and processing flowability in low-viscosity acidic beverage systems by matching the ratio of pectin extract concentrate to fine fruit peel fiber slurry, shear homogenization, and acidity control, thereby enabling effective retention and coating of water-soluble pectin on the surface of fine fruit peel fibers.

[0086] like Figure 1 As shown, using Examples 1, 9, and 11 as samples, the relationship between pectin retention rate and 30-day sedimentation rate was compared. Example 1 showed a pectin retention rate of approximately 50.0% and a 30-day sedimentation rate of approximately 10.0 wt%; while Comparative Examples 9 and 11 both showed a decreasing trend in pectin retention rate and an increasing trend in 30-day sedimentation rate. This result indicates that when pectin retention and coating on the surface of fine pericarp fiber particles are insufficient, the hydrophilicity of the particle surface, interfacial stability, and interparticle dispersion barrier all decrease, leading to easier particle aggregation and sedimentation. Therefore, the pectin coating layer is not simply a soluble thickening component in beverages, but rather a key structural factor regulating the interfacial properties and dispersion state of fine pericarp fiber particles, playing a crucial role in improving the storage stability of acidic beverage systems.

[0087] Based on this, Figure 2The comprehensive performance of each sample was further evaluated from the aspects of suspension stability and flowability. The results showed that the 30-day sedimentation rate of Example 1 was approximately 10.0 wt%, and the apparent viscosity was approximately 5.0 mPa·s, which is in the equilibrium range between low sedimentation rate and moderate viscosity. In contrast, some comparative examples, although having lower apparent viscosity, showed significantly higher 30-day sedimentation rates, indicating that simply reducing the system viscosity cannot guarantee the stable suspension of fine fruit peel fiber particles; while some systems could delay sedimentation by increasing viscosity, but this would sacrifice the flowability required for processing, transportation, bottling, and drinking taste. These results demonstrate that the advantage of this invention lies in forming a stable dispersion structure by coating fine fruit peel fiber composite particles with pectin, rather than passively suppressing sedimentation by relying on a high-viscosity system, thus effectively solving the problem of the difficulty in balancing suspension stability and processing flowability.

[0088] like Figure 3 As shown, at shear rates of 1–1000 s -1 The apparent viscosity changes of Example 1 and several comparative examples were tested within a certain range. Example 1 showed a viscosity change of 50 s. -1 The apparent viscosity at the vicinity is approximately 5.0 mPa·s, exhibiting a slight shear-thinning trend with increasing shear rate. This rheological characteristic indicates that, under low shear or static conditions, the pectin-coated microfiber composite particles in the system provide structural support, which helps to inhibit particle sedimentation. Under higher shear conditions, such as during pumping, homogenization, filling, or consumption, the system viscosity does not increase significantly, maintaining good flowability. This demonstrates that the pectin beverage obtained by this invention possesses both suspension support during storage and smooth flowability during processing and consumption.

[0089] Furthermore, such as Figure 4 As shown, the sedimentation rate changes of Example 1 and several comparative examples during the storage process from 0 to 30 days were recorded. The sedimentation rate of Example 1 increased only slowly with the extension of storage time, reaching approximately 10.0 wt% at 30 days, which was lower than that of most comparative examples. This result indicates that the pectin-coated microfiber composite particles formed by the present invention can maintain a good dispersion state in acidic beverage environments, reducing the probability of particle collision aggregation, flocculation, and gravity sedimentation. Compared with the comparative examples where the sedimentation rate increased rapidly, Example 1 showed a more stable suspension retention capacity during long-term storage, indicating that the present invention effectively improves the long-term dispersion stability of pectin fiber particles in beverages through the synergistic effect between the coating structure and particle micronization.

[0090] To further determine the impact of the amount of composite particles on the stability and flowability of the system, Figure 5Based on the basic formulation and preparation conditions of Example 1, only the content of pectin-coated microfiber composite particles was changed, ranging from 0.10 to 1.20 wt%. The results showed that increasing the composite particle content reduced the 30-day sedimentation rate and increased the apparent viscosity, indicating that increasing the composite particle content enhances the spatial barrier and weak network support between particles within the system, thereby improving suspension stability. However, excessively high composite particle content increases the system's flow resistance, which is detrimental to processing, bottling, and drinking taste. Therefore, the composite particle content is not necessarily better the higher it is, but should be controlled within a range that balances sedimentation inhibition and suitable viscosity. In Example 1, with a composite particle content of 0.20 wt%, a good balance between stability and flowability was achieved under conditions of a 30-day sedimentation rate of approximately 10.0 wt% and an apparent viscosity of approximately 5.0 mPa·s, demonstrating the rationality of the formulation parameters in this invention.

[0091] At the macroscopic level of appearance Figure 6 Optical photographs were taken of the final product of Example 1 and the final product of Comparative Example 11 to evaluate the effects of high-speed shearing and homogenization on the appearance uniformity, turbidity distribution and sedimentation tendency of acidic ready-to-drink pectin beverages. Figure 6 In Example 1, the final acidic pectin beverage contained 0.20 wt% composite particles, 0.02 wt% organic acids, and a pH of 3.2. The composite particles had a D50 of 20 μm, a D90 of 80 μm, a pectin retention rate of 50%, an apparent viscosity of 5 mPa·s, and a sedimentation rate of 10 wt% after standing at room temperature for 30 days. The sample exhibited a relatively uniform, slightly turbid dispersion, without significant large-particle flocculation or severe stratification, indicating that the pectin-coated fine pericarp fiber composite particles could maintain good dispersion stability even in a low-viscosity acidic environment. Figure 6 Comparative Example 11 (shown in b) has the same composite particle content, organic acid content, and pH as Example 1, but the 3000 rpm high-speed shearing and 5 MPa homogenization treatments were omitted, and only 300 rpm paddle stirring for 5 minutes was used. Its macroscopic appearance showed more uneven turbidity, flocculent aggregation, and sedimentation stratification, indicating that low-speed stirring alone is insufficient to fully combine pectin with fine pericarp fibers, and it is also difficult to form a stable and homogeneous acidic pectin beverage system. Therefore, high-speed shearing and homogenization are crucial process steps to promote pectin coating of fine pericarp fibers and the formation of a stable dispersion system.

[0092] Figure 7 Further verification of the structural reasons for the aforementioned differences in macroscopic stability was conducted from the perspectives of microscopic morphology and spatial distribution of elements. Figure 7a is a low-magnification SEM image of the final product of Example 1. It can be seen that the pectin-coated microfiber composite particles with D50 of 20 μm and D90 of 80 μm are evenly distributed within a large observation range, with few aggregates, indicating that the composite particles can still maintain a stable micron-level dispersion state after sterilization and filling. Figure 7 b is a low-magnification SEM image of the final product of Comparative Example 11. It can be seen that after removing high-speed shearing and homogenization, the particles are more likely to form flocculent aggregates and local accumulation, indicating that simple low-speed paddle stirring is insufficient to achieve full dispersion and stabilization of composite particles.

[0093] Further observation of the meso-magnification SEM image, Figure 7 In Example 1 shown in c, the outlines of individual or a few composite particles are relatively clear, indicating that wet grinding combined with subsequent shear homogenization and composite treatment can maintain the target particle size hierarchy and avoid significant re-agglomeration of particles in the subsequent acidic system. In contrast, Figure 7 As shown in Comparative Example 11, there are more mutual adhesions, bridging and irregular aggregations at the edges of the particles. This indicates that eliminating high-speed shearing and homogenization will weaken the uniformity of pectin on the surface of fine pericarp fibers, making it easier for particles to connect through exposed fibers or local pectin clumps.

[0094] Under high-magnification SEM observation Figure 7 The composite particles in Example 1 shown in Figure e have a relatively continuous covering texture and a relatively complete interface morphology. Combined with its approximately 50% pectin retention and coating rate, this indicates that water-soluble pectin can form an effective retention and coating on the surface of fine fruit peel fibers, thereby improving the hydrophilicity and dispersion stability of the particle interface. Figure 7 In Comparative Example 11 shown in f, exposed fiber fragments, local pectin clumps, and interparticle bridging structures are more likely to appear on the particle surface, indicating that under low-speed stirring conditions, the pectin distribution is uneven and the interfacial composite degree is insufficient, which leads to a decrease in particle dispersion stability.

[0095] also, Figure 7 g and Figure 7 The SEM-EDS surface scan images were used to compare the spatial distribution of elemental signals in the particle observation areas of Example 1 and Comparative Example 11. The C and O elemental signals corresponded to the particle outlines; the elemental signal distribution in Example 1 was more uniform, while in Comparative Example 11, the elemental signals were more locally clustered along the aggregate morphology. The SEM-EDS surface scan results were used to assist in evaluating particle morphology and component distribution, and were not used as the sole criterion for pectin coating status based on a single elemental signal.

[0096] In conclusion, Figures 1 to 7This invention demonstrates, from multiple perspectives including performance indicators, rheological behavior, storage stability, formulation dosage window, macroscopic appearance, and microstructure, that by matching the ratio of water-soluble pectin extract concentrate to fine pectin fiber slurry, combined with shear homogenization and acidity control, pectin effectively coats the surface of fine pectin fibers, thereby achieving stable particle dispersion in acidic pectin beverages. Compared to comparative examples, this invention avoids the problem of decreased pectin coating capacity caused by strong acid heat treatment and overcomes the problem of decreased flowability caused by simply increasing fiber content or system viscosity. It achieves a synergistic unity between pectin extraction and utilization, composite particle stability, beverage suspension retention, and processing flowability, proving the effectiveness and practical value of the technical solution.

[0097] Table 1 Performance of Examples and Comparative Examples

[0098] In Table 1, the pectin retention rate of Examples 1 to 4 and Comparative Examples 1 to 8 and Comparative Example 11 is the pectin retention and coating rate; the pectin retention rates of Comparative Example 9 and Comparative Example 10 respectively characterize the degree of pectin retention in the particulate phase in the fiber system without the addition of water-soluble pectin extract concentrate and the water-soluble pectin system without fine pericarp fibers.

[0099] As can be seen from the performance of the examples and comparative examples in the table, Examples 1–4 show a relatively coordinated trend in pectin solids recovery rate, pectin retention and coating rate, composite particle size control, 30-day sedimentation rate, and apparent viscosity. In the conventional single-variable comparative examples, deviations in composite particle content, organic acid, pectin ratio, particle size, extraction pH, extraction temperature, shear speed, or homogenization pressure resulted in varying degrees of adverse changes in sedimentation rate or coating rate. Comparative examples 9–11 show that when water-soluble pectin is lacking, fine pericarp fibers are lacking, or the shear homogenization composite process is disrupted, it is difficult to maintain both coating rate and suspension state simultaneously, indicating that the data trend corresponds to a balance between suspension stability and processing flowability.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A pectin beverage, characterized in that, The pectin beverage contains water-soluble pectin extracted from fruit peels, and by total mass of the pectin beverage, it comprises: Pectin-coated microfiber composite particles, 0.20–1.20 wt%; Organic acids 0.02–0.25 wt%; Water used in beverage production should be replenished to 100 wt%. The pectin-coated microfiber composite particles include microfibers and water-soluble pectin extracted from the pericarp, which coats the surface of the microfibers. The water-soluble pectin extracted from the fruit peel comes from fruit peels or fruit residue produced during food processing. The fine fruit peel fibers are derived from one or more of the following: apple peel for food processing, apple pomace for food processing, fragrant pear peel for food processing, pear pomace for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing.

2. The pectin beverage according to claim 1, characterized in that, The pectin-coated microfiber composite particles have a D50 of 20–80 μm and a D90 of 80–150 μm; the pectin beverage has a pH of 3.2–4.

2.

3. The pectin beverage according to claim 2, characterized in that, The water-soluble pectin extract concentrate used to prepare the pectin beverage is prepared through the following steps: B1. Select one or more of the following as raw materials: apple peel for food processing, apple pomace for food processing, fragrant pear peel for food processing, pear pomace for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing, and crush them to 2–8 mm. B2. Mix the fruit peel raw material with beverage production water at a mass ratio of 1:4–8, and adjust the pH of the system to 2.8–3.4 using a food-grade acidity regulator; B3. Extract at 75–90℃ for 45–120 min to obtain pectin extract slurry; B4. The pectin extraction slurry is subjected to solid-liquid separation to obtain pectin extract and pectin extraction residue; B5. Concentrate the pectin extract to a pectin solids content of 1–6 wt% to obtain the water-soluble pectin extract concentrate.

4. The pectin beverage according to claim 3, characterized in that, The pH value of the water-soluble pectin extract concentrate is 2.8–4.

2.

5. The pectin beverage according to claim 3, characterized in that, The fine pectin fiber pulp used to prepare the pectin beverage is prepared through the following steps: C1. Select one or more of the following as fruit peel fiber raw materials: the pectin extraction residue obtained in step B4, or the apple peel, apple pomace, pear peel, pear pomace, yellow peach peel, and yellow peach pomace that have been washed, crushed, and blanched: apple peel for food processing, apple pomace for food processing, pear peel for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing. C2. Wash the fruit peel fiber raw material with beverage production water until the pH of the washing solution is 4.0–6.0; C3. The washed fruit peel fiber raw material is formulated into a wet slurry with a solid content of 3–15 wt%; C4. The wet slurry is subjected to wet pulverization to obtain fine fruit peel fibers with a D50 of 20–80 μm and a D90 of 80–150 μm; C5. The slurry containing the fine pericarp fibers is kept at 80–95°C for 3–10 min to obtain the fine pericarp fiber slurry; C6. The solids content of the fine fruit peel fiber pulp is 3–15 wt%, and the pH value is 4.0–6.

0.

6. The pectin beverage according to claim 1, characterized in that, The fine fruit peel fibers include apple peel fibers derived from apple peels or apple pomace, and pear peel fibers derived from pear peels or pear pomace; the apple peel fibers account for 40–90 wt% of the dry weight of the fine fruit peel fibers, and the pear peel fibers account for 10–60 wt% of the dry weight of the fine fruit peel fibers, and the sum of the dry weight percentages of the apple peel fibers and the pear peel fibers does not exceed 100 wt%.

7. The pectin beverage according to claim 6, characterized in that, The fine pericarp fiber also includes yellow peach pericarp fiber derived from yellow peach pericarp or yellow peach pomace, wherein the yellow peach pericarp fiber accounts for 5–35 wt% of the dry weight of the fine pericarp fiber.

8. The pectin beverage according to claim 1, characterized in that, The pectin retention rate of the pectin-coated microfiber composite particles is 50–85%.

9. A method for preparing a pectin beverage as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Fruit peel pretreatment: Select one or more of the following as fruit peel raw materials: apple peel for food processing, apple pomace for food processing, fragrant pear peel for food processing, pear pomace for food processing, yellow peach peel for food processing, and yellow peach pomace for food processing. Crush them to 2–8 mm and blanch them at 85–95℃ for 2–8 min to obtain pretreated fruit peel raw materials. S2. Provides a water-soluble pectin extract concentrate and a fine pericarp fiber slurry, wherein the water-soluble pectin extract concentrate is prepared from a portion of the pretreated pericarp raw material, and the fine pericarp fiber slurry is prepared from pectin extraction residue or another portion of the pretreated pericarp raw material; S3. The water-soluble pectin extract concentrate is mixed with the fine fruit peel fiber slurry. The pH of the mixture is adjusted to 3.3–4.2 using a food-grade acidity regulator. The mixture is then treated at 40–65°C with a shear speed of 3000–8000 rpm for 5–25 min and homogenized at 5–30 MPa for 1–3 passes to obtain a pectin-coated fine fruit peel fiber composite particle slurry. S4. Mix the pectin-coated micro-peel fiber composite particle slurry with beverage production water and organic acid to obtain the formulated pectin beverage. S5. The prepared pectin beverage is sterilized and bottled to obtain the pectin beverage, wherein the pH value of the prepared pectin beverage is 3.2–4.

2.

10. The method according to claim 9, characterized in that, In step S5, the sterilization is performed at 85–95°C for 15–60 seconds, or at 110–135°C for 2–10 seconds. In three consecutive batches of pectin beverages, the inter-batch coefficient of variation (D50) of the pectin-coated micro-peel fiber composite particles was 2–10%.

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