A fiber-enriched pectin product and a method for its preparation

Abstract

The application belongs to the field of fruit and vegetable functional food raw materials, and provides a pectin product rich in fiber and a preparation method thereof, wherein apple-derived pectin extract and apple-derived insoluble dietary fiber slurry are directly mixed in an aqueous phase, and the acidity is adjusted by using citric acid monohydrate and sodium citrate dihydrate, so as to form apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles, the content of dietary fiber, dispersion stability, low water activity and process batch stability are considered, the problem that high-fiber fortification and dispersion and drying storage and pectin hydration performance are difficult to unify is solved, and the application is suitable for high-fiber food ingredients and fruit and vegetable by-product resource utilization.

Description

Technical Field

[0001] This invention relates to the field of functional food ingredients from fruits and vegetables, specifically to a fiber-rich pectin product and its preparation method. Background Technology

[0002] With the continuous development of apple deep processing industries such as juice, pulp, and jam, the resource utilization of by-products such as apple pomace has attracted attention from the food ingredients, functional foods, and fruit and vegetable processing industries. Apple pomace typically contains cellulose, hemicellulose, pectin, and other cell wall-related components, making it suitable as a dietary fiber fortification raw material and pectin source. However, in practical food ingredient applications, it not only requires a high contribution of dietary fiber but also acceptable wetting, dispersion, particle size, and mouthfeel in aqueous systems. For powdered functional food ingredients, fiber content, dispersion stability, storage stability, low moisture content, and industrial processing window often simultaneously affect product value. Simply increasing the fiber ratio may not meet the comprehensive needs of beverages, instant powders, baking ingredients, compound nutritional powders, and high-value utilization scenarios of fruit and vegetable by-products. Therefore, developing apple-derived compound granules that can balance fiber fortification, pectin hydration, low moisture storage, and batch consistency is of great significance for improving the utilization efficiency of apple processing by-products and expanding the application of high-fiber food ingredients.

[0003] Existing technologies for utilizing apple pomace mostly focus on extracting pectin, extracting dietary fiber, or treating dietary fiber using enzymatic methods, alkaline methods, pulverization, or drying. For example, Chinese patent CN107874265A discloses a method for extracting dietary fiber from apple pomace, which obtains the dietary fiber through mixed enzyme treatment, centrifugation, and drying. Another example is CN101891839B, which discloses a method for extracting and separating pectin from apple pomace, emphasizing the extraction of pectin from apple pomace. CN101664165B discloses a process for extracting non-pectin-soluble dietary fiber from apple pomace, focusing on the reuse of apple pomace after pectin extraction. However, the aforementioned disclosed technologies usually focus on the separation or modification of a certain type of component, which can easily lead to problems such as difficulty in redispersing, uneven coating, hard powder clumps, or long process chains when apple-derived pectin and apple-derived insoluble dietary fiber are compounded in the subsequent process. Furthermore, they do not pay enough attention to the coupling relationship between high fiber fortification, pectin hydration performance, low moisture storage, and batch particle size stability, making it difficult to directly meet the demand for pectin products that are rich in fiber and have stable dispersion performance. Summary of the Invention

[0004] The purpose of this invention is to provide a fiber-rich pectin product and its preparation method, which solves the technical problems of decreased dispersion stability when increasing the proportion of apple-derived insoluble dietary fiber, the impact on dietary fiber fortification function when increasing the degree of pectin coating, and the damage to pectin thickening performance during fortification and drying storage.

[0005] This invention achieves a synergistic balance between the reinforcing function of the fiber skeleton and the dispersion stability brought by pectin hydration by in situ coating the surface and pores of apple-derived insoluble dietary fiber with apple-derived pectin, and by adjusting the acidity with citric acid monohydrate and sodium citrate dihydrate. This also reduces the adverse effects of the drying process on pectin hydration and thickening performance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A fiber-rich pectin product, comprising apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles; based on a dry basis total mass of 100.00 wt%, the fiber-rich pectin product comprises: Apples contain 58.00-83.17 wt% insoluble dietary fiber. Apple-derived pectin: 16.33-40.00 wt%; The total content of citric acid monohydrate and sodium citrate dihydrate is 0.20-2.00 wt%; The apple-derived insoluble dietary fiber, apple-derived pectin, citric acid monohydrate, and sodium citrate dihydrate are all final form components of the fiber-rich pectin product, and their combined dry basis mass percentage is 100.00 wt%; the dry basis mass ratio of the apple-derived insoluble dietary fiber to the apple-derived pectin is 1:0.20 to 1:0.69. In the apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles, the apple-derived pectin is distributed on the surface and in the pores of the apple-derived insoluble dietary fiber, forming an in-situ coated structure. The D50 of the apple-derived insoluble dietary fiber-apple-derived pectin in situ coated composite particles is 30.00-180.00 μm, the coating rate of apple-derived pectin to apple-derived insoluble dietary fiber is 60.00-95.00%, and the coating rate is the percentage of the mass of quantifiable apple-derived pectin in the solid phase after elution to the mass of quantifiable apple-derived pectin in the solid phase before elution. The total dietary fiber content of the fiber-rich pectin product is 60.00-85.00g / 100g, and the total dietary fiber content is determined according to GB 5009.88-2023, based on the original mass of the fiber-rich pectin product. The fiber-rich pectin product has a moisture content of 4.00-10.00 wt% and a water activity of 0.20-0.60 at 25.00℃.

[0007] Unless otherwise stated, apple-derived pectin and apple-derived insoluble dietary fiber in this specification refer to the corresponding apple-derived components provided by apple-derived pectin extract and apple-derived insoluble dietary fiber pulp, respectively, and their mass fraction is calculated based on the dry weight of the corresponding component added to the product; the solid content of apple-derived pectin extract and apple-derived insoluble dietary fiber pulp both refer to the total solids mass fraction of the corresponding system, and the dry weight ratio in step S2 is not directly replaced by the total mass or total solids mass of the two pulps.

[0008] Furthermore, the apple-derived pectin extract used to prepare the apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles is prepared through the following steps: A1. Mix apple pomace with deionized water, wherein the mass ratio of apple pomace to deionized water is 1:6.00-1:15.00; A2. Add citric acid monohydrate to the mixture obtained in step A1 to adjust the pH to 2.20-3.20; A3. Extract at 70.00-85.00℃ and normal pressure for 60.00-120.00 min to obtain acid-heated extract; A4. The acid-heated extract is subjected to solid-liquid separation to obtain a liquid phase and a solid residue, wherein the liquid phase is the apple-derived pectin extract; the solid-liquid separation is performed by filtration or centrifugation. A5. Adjust the solid content of the apple-derived pectin extract to 1.00-8.00 wt%; The pH of the apple-derived pectin extract is 2.20-3.20.

[0009] Furthermore, the apple-derived insoluble dietary fiber pulp used to prepare the apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles is prepared through the following steps: B1. Take the solid residue obtained in step A4 and wash it with deionized water until the pH of the washing solution is 3.00-5.50; B2. The washed solid residue is wet-milled to obtain a wet slurry; B3. Adjust the solid content of the wet grinding slurry to 5.00-15.00 wt%; B4. Control the D50 of apple-derived insoluble dietary fiber in the wet pulp to be 20.00-100.00 μm to obtain the apple-derived insoluble dietary fiber pulp; The mass fraction of coarse particles in the apple-derived insoluble dietary fiber pulp that were not dispersed by wet milling is 0.00-5.00 wt%.

[0010] Furthermore, the apple pomace used to prepare the fiber-rich pectin product is derived from the apple juicing, apple pulp, or apple sauce processing process, and the initial moisture content of the apple pomace is 65.00-85.00 wt%, and the total mass fraction of the apple core and seeds in the apple pomace is 0.00-5.00 wt%.

[0011] Furthermore, the D50 of the apple-derived insoluble dietary fiber in the apple-derived pectin in-situ coated composite particles is 20.00-100.00 μm.

[0012] Furthermore, the pH of the aqueous dispersion system of the fiber-rich pectin product with a mass fraction of 1.00 wt% is 3.20-4.80, and the hard agglomerate residue rate is 0.00-5.00 wt%, which is determined using an 180 μm sieve.

[0013] This invention employs a design of in-situ coated composite particles of apple-derived insoluble dietary fiber and apple-derived pectin, primarily aimed at achieving a synergistic balance between dietary fiber fortification and water dispersion stability. In existing technologies, increasing the proportion of apple-derived insoluble dietary fiber generally enhances fiber supply; however, the fiber skeleton's slow water absorption, rough surface, and interparticle entanglement easily lead to clumping and sedimentation. While increasing apple-derived pectin can improve hydration and suspension, an excessively high pectin proportion dilutes the fiber contribution and increases the system's viscosity burden. This invention distributes apple-derived pectin on the surface and within the pores of apple-derived insoluble dietary fiber, and adjusts acidity using citric acid monohydrate and sodium citrate dihydrate. This weakens fiber aggregation in the pectin hydration layer, while the fiber skeleton limits excessive pectin viscosity, thus balancing these mutually restrictive properties.

[0014] This invention also discloses a method for preparing any of the aforementioned fiber-rich pectin products, comprising the following steps: S1. Provides apple-derived pectin extract and apple-derived insoluble dietary fiber pulp; S2. Mix apple-derived insoluble dietary fiber in apple-derived insoluble dietary fiber pulp with apple-derived pectin in apple-derived pectin extract at a dry basis mass ratio of 1:0.20 to 1:0.69. S3. Add citric acid monohydrate and sodium citrate dihydrate to the mixture obtained in step S2, and adjust the pH to 3.20-4.20; S4. Stir the mixture obtained in step S3 at 40.00-65.00℃ and normal pressure for 30.00-90.00 min to obtain the coated slurry; at the end of the coating treatment, the difference between two adjacent pH measurements is 0.00-0.20, and the coating rate of apple-derived pectin to apple-derived insoluble dietary fiber is 60.00-95.00%; S5. Adjust the coating slurry to a solid content of 10.00-25.00 wt% and spray dry it; the inlet air temperature of the spray dryer is 150.00-180.00℃ and the outlet air temperature is 75.00-90.00℃; granulate and sieve the powder obtained from the spray drying to obtain the fiber-rich pectin product.

[0015] Furthermore, in step S1, the apple-derived pectin extract is the apple-derived pectin extract prepared according to steps A1 to A5, and the apple-derived insoluble dietary fiber pulp is the apple-derived insoluble dietary fiber pulp prepared in steps B1 to B4.

[0016] Furthermore, step S2 does not include the step of preparing the apple-derived pectin extract into apple-derived pectin powder separately, but instead the apple-derived pectin extract is directly mixed with the apple-derived insoluble dietary fiber pulp.

[0017] Furthermore, the apple-derived pectin extract provided in step S1 is a liquid phase obtained from the same batch of apple pomace through acid-heat extraction and solid-liquid separation, and the apple-derived insoluble dietary fiber pulp is prepared from the solid residue obtained by the solid-liquid separation.

[0018] Furthermore, steps S1 to S4 are all carried out in an aqueous system.

[0019] Furthermore, the fiber-rich pectin product obtained in step S5 has a D50 of 30.00-180.00 μm, a moisture content of 4.00-10.00 wt%, and a water activity of 0.20-0.60.

[0020] Furthermore, under conditions of three consecutive batches of production, the inter-batch coefficient of variation of the D50 of the fiber-rich pectin product was 2.00-12.00%.

[0021] Furthermore, the process yield of the method for preparing the fiber-rich pectin product is 70.00-95.00 wt%, and the process yield is used as an evaluation index for process stability and material utilization during the production process.

[0022] This invention utilizes a direct aqueous phase mixing and spray drying process involving apple-derived pectin extract and apple-derived insoluble dietary fiber slurry to achieve and maintain the aforementioned synergistic effects. Existing techniques, such as separating and drying pectin powder before compounding it with fiber powder, often result in uneven pectin rehydration and insufficient fiber surface coating. Simply intensifying drying to obtain a storage-stable powder may weaken pectin hydration and thickening properties. This invention obtains both liquid and solid phase residues from the same batch of apple pomace, allowing apple-derived pectin to contact apple-derived insoluble dietary fiber under aqueous phase conditions. Under controlled pH, temperature, and time conditions, a coated slurry is formed, which is then spray-dried to fix the composite particle state. This reduces the dual side effects of uneven dispersion and drying damage, maintaining the synergistic relationship between fiber strengthening, pectin hydration, and storage stability during the preparation process.

[0023] Apple-derived insoluble dietary fiber primarily serves as dietary fiber fortification and a particle skeleton. However, when it exists alone or in excessive proportion, it can lead to rough particle surfaces, uneven hydrophilic wetting, and bridging between fibers, increasing the sieve residue rate of hard clumps and reducing dispersion stability. Apple-derived pectin mainly improves hydration, lubrication, and suspension. However, when it exists alone or in excessive proportion, it may dilute the contribution of total dietary fiber and cause excessive viscosity in the system, negatively impacting the powder processing and reconstitution performance of high-fiber products. This invention directly mixes apple-derived pectin extract with apple-derived insoluble dietary fiber slurry in an aqueous phase. This allows the apple-derived pectin to penetrate the fiber surface and pores. Furthermore, the presence of citric acid monohydrate and sodium citrate dihydrate creates a suitable acidity environment, promoting coordination between the pectin hydration layer and the fiber skeleton, ultimately balancing their mutually restrictive properties.

[0024] Beneficial technical effects 1. By distributing apple-derived pectin on the surface and pores of apple-derived insoluble dietary fiber to form an in-situ coating structure, it is possible to improve the wetting and suspension state of fiber particles while maintaining a high proportion of apple-derived insoluble dietary fiber, reduce the formation of hard clumps during powder preparation, and achieve a more coordinated technical effect of dietary fiber fortification function and dispersion stability.

[0025] 2. By directly mixing apple-derived pectin extract with apple-derived insoluble dietary fiber pulp, the problem of uneven rehydration caused by first preparing apple-derived pectin into powder and then compounding is avoided. This makes it easier for pectin to enter the fiber surface and pores in the aqueous phase, which is beneficial to improving the uniformity of the coating structure and shortening the compounding process chain.

[0026] 3. By adjusting the acidity of the coating system with citric acid monohydrate and sodium citrate dihydrate, and maintaining a controllable acidity in the 1.00wt% aqueous dispersion system of the product, the stability of the dispersion system is improved, while avoiding excessive viscosity caused by simply increasing pectin.

[0027] 4. By adjusting the coating slurry to a solid content of 10.00-25.00 wt% and then spray drying it, and controlling the moisture content and water activity of the finished product, the product can achieve a lower storage risk and a better powder morphology, while reducing the adverse effects of strong drying conditions on the hydration and thickening properties of apple-derived pectin.

[0028] 5. By using the coefficient of variation between three consecutive batches of D50 and the process yield as preferred quality control indicators, the stability of industrial preparation can be evaluated from the aspects of particle size consistency and material utilization. This helps to improve the batch controllability and production adaptability of fiber-rich pectin products in functional food ingredients. Attached Figure Description

[0029] Figure 1 This is a dot plot of the D50 inter-batch coefficient of variation for Example 1, Comparative Example 8, and Comparative Example 11.

[0030] Figure 2 The pH change curves are for the coating process of Example 1, Comparative Example 5, and Comparative Example 6.

[0031] Figure 3 This is a combined evaluation chart of water activity and apparent viscosity for Example 1 and Comparative Example 7.

[0032] Figure 4 The viscosity-shear rate curves are for Example 1 and Comparative Example 7.

[0033] Figure 5 The image shows the hard agglomerate residue rates of Examples 1, 8, 9 and 11.

[0034] Figure 6 The graph shows the effect of the dry weight ratio of apple-derived pectin to apple-derived insoluble dietary fiber on the coating rate and the sieve residue rate of hard clumps.

[0035] Figure 7 This is a comparison of macroscopic optical photographs of the final product of Example 1 and the final product of Comparative Example 7; wherein, Figure 7 Figure (a) in the figure is a macroscopic optical photograph of the final product of Example 1; Figure 7 Figure (b) in the figure is a macroscopic optical photograph of the final product of Comparative Example 7.

[0036] Figure 8 The images show the SEM morphology and SEM-EDS surface scan comparison of the final product of Example 1 and the final product of Comparative Example 7; wherein, Figure 8 Figure (a) in the figure is a low-magnification SEM image of the final product of Example 1; Figure 8 Figure (b) in the figure is a low-magnification SEM image of the final product of Comparative Example 7; Figure 8 Figure (c) in the figure is a medium magnification SEM image of the final product of Example 1; Figure 8Figure (d) in the figure is a medium magnification SEM image of the final product of Comparative Example 7; Figure 8 Figure (e) in the figure is a high-magnification SEM image of the final product of Example 1; Figure 8 Figure (f) in the figure is a high-magnification SEM image of the final product of Comparative Example 7; Figure 8 Figure (g) in the figure is a SEM-EDS surface scan of the final product of Example 1; Figure 8 Figure (h) in the figure is a SEM-EDS surface scan of the final product of Comparative Example 7. 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] Example 1 In this embodiment, the objective is to prepare a fiber-rich pectin product with a dry basis weight of 1000.00 g. The product is in the form of spray-dried powder. In the dry basis composition of this embodiment, apple-derived insoluble dietary fiber is 83.17 wt%, apple-derived pectin is 16.63 wt%, and the total content of citric acid monohydrate and sodium citrate dihydrate is 0.20 wt%, of which citric acid monohydrate is 0.12 wt% and sodium citrate dihydrate is 0.08 wt%. Apple pomace is obtained from the apple juicing process, with an initial moisture content of 65.00 wt% and a total mass fraction of fruit cores and seeds of 0.00 wt%. The apple pomace is used after manual sorting. Deionized water is food processing water, and both citric acid monohydrate and sodium citrate dihydrate are food-grade and commercially available.

[0039] A: To prepare apple-derived pectin extract, take 10.00 kg of apple pomace and add 60.00 kg of deionized water at a mass ratio of apple pomace to deionized water of 1:6.00. Stir at 300 rpm for 10.00 min under mechanical stirring. Add citric acid monohydrate to the mixture to adjust the pH to 2.20. Heat to 70.00℃ under normal pressure and air atmosphere and maintain the temperature for 60.00 min to obtain an acid-heated extract. After extraction, perform solid-liquid separation using an 80-mesh filter cloth to obtain a liquid phase and solid residue. The liquid phase is the apple-derived pectin extract. Concentrate the apple-derived pectin extract at 55.00℃ and normal pressure to a solid content of 1.00 wt%. The pH of the apple-derived pectin extract is 2.20.

[0040] B: To prepare apple-derived insoluble dietary fiber pulp, the above-mentioned solid residue was washed with deionized water. Each time, deionized water was added at a ratio of 3.00 times the mass of the solid residue. Solid-liquid separation was performed after washing until the pH of the washing liquid reached 3.00. The washed solid residue was then added to a wet milling apparatus for processing at a speed of 2800 rpm for 20.00 min, yielding a wet-milled pulp. Deionized water was added to the wet-milled pulp to adjust the solid content to 5.00 wt%. Laser diffraction particle size analysis showed that the D50 of the apple-derived insoluble dietary fiber in the wet-milled pulp was 20.00 μm, and the mass fraction of coarse particles not dispersed by wet milling was 0.00 wt%, thus obtaining the apple-derived insoluble dietary fiber pulp.

[0041] S1 to S3: Apple-derived pectin extract and apple-derived insoluble dietary fiber pulp are provided for aqueous phase mixing and acidity adjustment. The apple-derived insoluble dietary fiber in the apple-derived insoluble dietary fiber pulp is mixed with the apple-derived pectin in the apple-derived pectin extract at a dry weight ratio of 1:0.20. During mixing, the apple-derived insoluble dietary fiber pulp is first added to the mixing tank, followed by the apple-derived pectin extract under stirring at 300 rpm for 20.00 min. Citric acid monohydrate and sodium citrate dihydrate are then added to the resulting mixture to adjust the pH to 3.20.

[0042] S4: A coating process was performed. The mixture obtained in step S3 was stirred at 300 rpm for 30.00 min at 40.00℃, normal pressure, and in air atmosphere to obtain a coated slurry. The pH was measured every 10.00 min during the coating process. At the end of the coating process, the difference between two consecutive pH measurements was 0.00, and the coating rate of apple-derived pectin to apple-derived insoluble dietary fiber was 60.00%. The coating rate is the percentage of quantifiable apple-derived pectin in the solid phase after elution to the percentage of quantifiable apple-derived pectin in the solid phase before elution. The proportion of particle surface coverage area statistically analyzed by microscopic images was used as an auxiliary verification indicator.

[0043] S5: Spray drying, granulation, and sieving are performed. The coating slurry is adjusted to a solid content of 10.00 wt%. Spray drying is carried out under the conditions of an inlet air temperature of 150.00℃, an outlet air temperature of 75.00℃, and atmospheric pressure. The atomization pressure is 0.25 MPa, and the feed rate is 12.00 mL / min. The powder obtained from spray drying is equilibrated at 25.00℃ and 45.00% relative humidity for 2.00 h before granulation and sieving. A 180 μm sieve is used for sieving to obtain a fiber-rich pectin product.

[0044] Quality testing methods and results: The fiber-rich pectin product of this embodiment was tested for total dietary fiber content according to GB 5009.88-2023, and the result was 84.50 g / 100 g. The particle size of the composite particles was determined by laser diffraction particle size analysis according to GB / T 19077-2024. Water was used as the dispersion medium, and the particles were ultrasonically dispersed for 60.00 s. The volume distribution D50 was recorded as 30.00 μm. The moisture content was determined to be 4.00 wt% by the drying and weighing method. The water activity was measured to be 0.20 at 25.00℃ using a water activity meter. The product was prepared into a 1.00 wt% aqueous dispersion system. After stirring at 25.00℃ for 300 rpm for 5.00 min, the pH was measured to be 3.20, and the hard agglomerate residue was 5.00 wt%. The inter-batch coefficient of variation of D50 was 12.00% when preparing three consecutive batches, and the process yield was 70.00 wt%.

[0045] Features and application scenarios of this embodiment: This embodiment adopts a relatively conservative low ratio scheme, with a high proportion of apple-derived insoluble dietary fiber and a low proportion of apple-derived pectin. The coating treatment and drying conditions are relatively mild, making it suitable for powdered food ingredients that emphasize dietary fiber fortification, low moisture storage, and basic reconstitution dispersion performance.

[0046] Example 2 Raw materials and proportions: This embodiment aims to prepare a fiber-rich pectin product with a dry basis weight of 1000.00g. In the dry basis composition, apple-derived insoluble dietary fiber is 58.00wt%, apple-derived pectin is 40.00wt%, and the total content of citric acid monohydrate and sodium citrate dihydrate is 2.00wt%, of which citric acid monohydrate is 1.20wt% and sodium citrate dihydrate is 0.80wt%. The apple pomace is derived from the applesauce processing process, with an initial moisture content of 85.00wt% and a total mass fraction of fruit cores and seeds of 5.00wt%. The apple pomace is used after sorting, crushing, and homogenization. All raw materials are food-grade or commercially available.

[0047] Preparation process of apple-derived pectin extract: 12.00 kg of apple pomace was mixed with deionized water at a mass ratio of 1:15.00, and 180.00 kg of deionized water was added. The mixture was stirred mechanically at 450 rpm for 15.00 min. Citric acid monohydrate was added to adjust the pH to 3.20. The mixture was heated to 85.00℃ under normal pressure and extracted for 120.00 min to obtain an acid-heated extract. After extraction, centrifugation was performed to separate the solid and liquid phases at 3500 rpm for 15.00 min, obtaining a liquid phase and a solid residue. The liquid phase was concentrated at 60.00℃ to a solid content of 8.00 wt% to obtain the apple-derived pectin extract with a pH of 3.20.

[0048] Preparation process of apple-derived insoluble dietary fiber pulp: Solid residue was collected and washed with deionized water until the pH of the washing solution reached 5.50. The washed solid residue was then wet-milled at 1800 rpm for 10.00 min to obtain a wet-milled pulp. The solid content of the wet-milled pulp was adjusted to 15.00 wt%, the D50 of the apple-derived insoluble dietary fiber was controlled to be 100.00 μm, and the mass fraction of coarse particles not dispersed by wet milling was 5.00 wt%, thus obtaining the apple-derived insoluble dietary fiber pulp.

[0049] Coating and Drying Process: Apple-derived insoluble dietary fiber from the apple-derived insoluble dietary fiber pulp and apple-derived pectin from the apple-derived pectin extract were mixed at a dry weight ratio of 1:0.69. First, the apple-derived pectin extract was added to a mixing tank, followed by the apple-derived insoluble dietary fiber pulp in batches over a period of 30.00 min while stirring at 450 rpm. Citric acid monohydrate and sodium citrate dihydrate were added to the mixture to adjust the pH to 4.20. The mixture was stirred at 65.00℃ and atmospheric pressure for 90.00 min to obtain the coated pulp. At the end of the coating process, the difference between two consecutive pH measurements taken 10.00 min apart was 0.20, and the coating rate was 95.00%. The coating slurry was adjusted to a solid content of 25.00 wt% and dried under the conditions of spray drying with an inlet air temperature of 180.00℃, an outlet air temperature of 90.00℃, an atomization pressure of 0.35 MPa, and a feed rate of 20.00 mL / min. The resulting powder was granulated and sieved to obtain a fiber-rich pectin product.

[0050] Quality testing methods and results: The total dietary fiber content of the product in this embodiment was determined to be 60.00 g / 100 g according to GB 5009.88-2023; the composite particle D50 was determined to be 180.00 μm according to GB / T 19077-2024 using laser diffraction particle size analysis; the moisture content was determined to be 10.00 wt% by the drying and weighing method; the water activity was determined to be 0.60 by a water activity meter at 25.00℃; the pH of the 1.00 wt% aqueous dispersion system was 4.80 after stirring at 25.00℃ and 300 rpm for 5.00 min, and the hard agglomerate residue was 0.20 wt%. The inter-batch coefficient of variation of D50 was 2.00% when preparing three consecutive batches, and the process yield was 95.00 wt%.

[0051] The features of this embodiment are: This embodiment adopts a high-load apple-derived pectin coating scheme, the ratio parameters are in the high pectin range, and the coating temperature, coating time and spray drying temperature are in the high process intensity range, which is suitable for high-fiber composite pectin powder that emphasizes dispersion stability, full coating and high production yield.

[0052] Example 3 This embodiment employs a medium-ratio and medium-particle-size scheme to prepare a fiber-rich pectin product with a dry basis weight of 1000.00 g. The dry basis composition is set as follows: 72.00 wt% apple-derived insoluble dietary fiber, 27.00 wt% apple-derived pectin, and a total of 1.00 wt% citric acid monohydrate and sodium citrate dihydrate, of which citric acid monohydrate is 0.60 wt% and sodium citrate dihydrate is 0.40 wt%. The apple pomace is derived from the apple pulp processing process, with an initial moisture content of 75.00 wt%, and the total mass fraction of fruit cores and seeds is 2.00 wt%.

[0053] Key parameters are as follows: apple pomace to deionized water mass ratio 1:10.00, acid-heat extraction pH 2.70, acid-heat extraction temperature 78.00℃, acid-heat extraction time 90.00 min, apple-derived pectin extract solid content 4.50 wt%, washing solution pH 4.20, wet milling pulp solid content 10.00 wt%, apple-derived insoluble dietary fiber pulp D50 of 60.00 μm, and coarse particle mass fraction not dispersed by wet milling 2.00 wt%.

[0054] In preparation, apple pomace was mixed with deionized water, and citric acid monohydrate was added to adjust the pH to 2.70. The mixture was then heated to 78.00℃ under normal pressure and extracted for 90.00 min to obtain an acid-heat extract. After centrifugation to separate the solid and liquid phases, the liquid phase was adjusted to a solid content of 4.50 wt% to serve as the apple-derived pectin extract. The solid residue was washed with deionized water until the pH of the washing liquid reached 4.20, and then wet-milled at 2200 rpm for 15.00 min to obtain an apple-derived insoluble dietary fiber pulp.

[0055] Apple-derived insoluble dietary fiber from apple-derived insoluble dietary fiber pulp and apple-derived pectin from apple-derived pectin extract were mixed at a dry weight ratio of 1:0.38. During mixing, the apple-derived insoluble dietary fiber pulp was added first, followed by the apple-derived pectin extract, with a stirring speed of 380 rpm and an addition time of 25.00 min. After adding citric acid monohydrate and sodium citrate dihydrate, the pH was adjusted to 3.70. The mixture was stirred at 52.00℃ and atmospheric pressure for 60.00 min to obtain the coated pulp. At the end of the coating treatment, the difference between two consecutive pH measurements was 0.10, and the coating rate was 78.00%. The coated pulp was adjusted to a solid content of 17.00 wt%, spray-dried at an inlet air temperature of 165.00℃ and an outlet air temperature of 82.00℃, and the resulting powder was granulated and sieved to obtain a fiber-rich pectin product.

[0056] Quality testing methods and results: In this embodiment, the total dietary fiber content of the product was determined to be 72.00 g / 100 g according to GB 5009.88-2023; the D50 of the composite particles was determined to be 95.00 μm according to GB / T 19077-2024; the moisture content was determined to be 6.50 wt% by the drying and weighing method; the water activity was determined to be 0.35 using a water activity meter at 25.00℃; the pH of the 1.00 wt% aqueous dispersion system was 3.80, and the hard agglomerate residue was 2.00 wt%. The inter-batch coefficient of variation of D50 was 6.00% when preparing three consecutive batches, and the process yield was 84.00 wt%.

[0057] The process features and application directions of this embodiment: This embodiment adopts a medium ratio, medium particle size and medium process intensity, and the ratio of apple-derived insoluble dietary fiber to apple-derived pectin is relatively balanced, which is suitable for conventional functional food raw materials that take into account fiber reinforcement, reconstitution dispersion, powder processing and process stability.

[0058] Example 4 I. Preparation Object and Raw Material State: The objective was to prepare a fiber-rich pectin product with a dry basis weight of 1000.00 g, which was a spray-dried powder. The dry basis composition included 69.00 wt% apple-derived insoluble dietary fiber, 29.50 wt% apple-derived pectin, and a total content of 1.50 wt% for citric acid monohydrate and sodium citrate dihydrate, of which citric acid monohydrate accounted for 0.90 wt% and sodium citrate dihydrate for 0.60 wt%. The apple pomace was derived from the mixed apple pomace processed from apple juicing and apple jam production, with an initial moisture content of 82.00 wt% and a total mass fraction of fruit cores and seeds of 4.50 wt%.

[0059] II. Preparation of Apple-Derived Pectin Extract: Apple pomace and deionized water were mixed at a mass ratio of 1:14.80 and dispersed at 400 rpm for 15.00 min. Citric acid monohydrate was added to adjust the pH to 3.18, and the mixture was heated to 84.80℃ under normal pressure and extracted for 118.80 min to obtain an acid-heated extract. After solid-liquid separation, a liquid phase and a solid residue were obtained from the acid-heated extract. The solid content of the liquid phase was adjusted to 7.86 wt% to obtain the apple-derived pectin extract with a pH of 3.18.

[0060] III. Preparation of Apple-Derived Insoluble Dietary Fiber Slurry: The solid residue was washed with deionized water until the pH of the washing solution reached 5.45. The washed solid residue was then wet-milled at 1900 rpm for 12.00 min to obtain a wet-milled slurry. The solid content of the wet-milled slurry was adjusted to 14.80 wt%, and the D50 of the apple-derived insoluble dietary fiber was controlled to be 98.40 μm, with the mass fraction of coarse particles not dispersed by wet milling being 4.90 wt%, thus obtaining the apple-derived insoluble dietary fiber slurry.

[0061] IV. Aqueous Phase Coating and Spray Drying: Apple-derived insoluble dietary fiber from apple-derived slurry and apple-derived pectin from apple-derived pectin extract were mixed at a dry weight ratio of 1:0.43. Citric acid monohydrate and sodium citrate dihydrate were added to the resulting mixture to adjust the pH to 4.18. The mixture was stirred at 420 rpm for 88.80 min at 64.50℃ and atmospheric pressure to obtain the coated slurry. At the end of the coating treatment, the difference between two consecutive pH measurements was 0.20, indicating that the coating rate of apple-derived pectin to apple-derived insoluble dietary fiber was 90.00%. The coated slurry was adjusted to a solid content of 24.70 wt%, and the spray drying process was carried out at an inlet air temperature of 179.40℃ and an outlet air temperature of 89.70℃. The resulting powder was granulated and sieved to obtain a fiber-rich pectin product.

[0062] V. Quality Testing Methods and Results: In this embodiment, the total dietary fiber content of the product was determined to be 70.00 g / 100 g according to GB 5009.88-2023; the D50 of the composite particles was determined to be 177.00 μm according to GB / T 19077-2024; the moisture content was determined to be 8.00 wt% by the drying and weighing method; the water activity was determined to be 0.45 at 25.00℃ using a water activity meter; the pH of the 1.00 wt% aqueous dispersion system was 4.77, and the hard agglomerate residue was 0.10 wt%. The inter-batch coefficient of variation of D50 was 8.00% when preparing three consecutive batches, and the process yield was 88.00 wt%.

[0063] VI. Applicable Scenarios of this Embodiment: This embodiment adopts extraction, wet grinding, coating and spray drying conditions that favor the high-value region. The composite particles have a larger particle size and a higher coating rate, which is suitable for scenarios requiring strong powder flowability, low hard agglomerate sieve residue rate and relatively stable batch particle size, such as instant food, compound nutritional powder and high-value utilization of fruit and vegetable by-products.

[0064] Comparative Example 1: Basically the same as Example 1, except that in step S2, the dry weight ratio of apple-derived insoluble dietary fiber to apple-derived pectin is adjusted to 1:0.10; in step A1, the weight ratio of apple pomace to deionized water is maintained at 1:6.00; in step A2, the pH of acid-heat extraction is maintained at 2.20; in step A3, the acid-heat extraction temperature is maintained at 70.00℃ and the acid-heat extraction time is maintained at 60.00 min; in step A5, the solid content of apple-derived pectin extract is maintained at 1.00 wt%; in step B1, the pH of washing solution is maintained at 3.00; in step B3, the solid content of wet grinding pulp is maintained at 5.00 wt%; in step B4, the D50 of apple-derived insoluble dietary fiber is maintained at 20.00 μm; in step S3, the pH is maintained at 3.20; in step S4, the coating temperature is maintained at 40.00℃ and the coating time is maintained at 30.00 min; in step S5, the solid content of coated pulp is maintained at 10.00 wt%, the spray drying inlet air temperature is maintained at 150.00℃, and the outlet air temperature is maintained at 75.00℃.

[0065] Comparative Example 2: Basically the same as Example 1, except that in step S2, the dry basis mass ratio of apple-derived insoluble dietary fiber to apple-derived pectin was adjusted to 1:0.85; in step A1, the mass ratio of apple pomace to deionized water was maintained at 1:6.00; in step A2, the pH of acid-heat extraction was maintained at 2.20; in step A3, the acid-heat extraction temperature was maintained at 70.00℃ and the acid-heat extraction time was maintained at 60.00 min; in step A5, the solid content of apple-derived pectin extract was maintained at 1.00 wt%; in step B1, the pH of washing solution was maintained at 3.00; in step B3, the solid content of wet grinding pulp was maintained at 5.00 wt%; in step B4, the D50 of apple-derived insoluble dietary fiber was maintained at 20.00 μm; in step S3, the pH was maintained at 3.20; in step S4, the coating temperature was maintained at 40.00℃ and the coating time was maintained at 30.00 min; in step S5, the solid content of coated pulp was maintained at 10.00 wt%; the spray drying inlet air temperature was maintained at 150.00℃ and the outlet air temperature was maintained at 75.00℃.

[0066] Comparative Example 3: Basically the same as Example 1, except that the coating treatment temperature in step S4 is adjusted to 30.00℃, the mass ratio of apple pomace to deionized water in step A1 is maintained at 1:6.00, the pH of acid-heat extraction in step A2 is maintained at 2.20, the acid-heat extraction temperature in step A3 is maintained at 70.00℃ and the acid-heat extraction time is maintained at 60.00 min, the solid content of apple-derived pectin extract in step A5 is maintained at 1.00 wt%, the pH of washing solution in step B1 is maintained at 3.00, the solid content of wet grinding pulp in step B3 is maintained at 5.00 wt%, the D50 of apple-derived insoluble dietary fiber in step B4 is maintained at 20.00 μm, the dry basis mass ratio in step S2 is maintained at 1:0.20, the pH in step S3 is maintained at 3.20, the coating time in step S4 is maintained at 30.00 min, the solid content of coated pulp in step S5 is maintained at 10.00 wt%, the inlet air temperature of spray drying is maintained at 150.00℃, and the outlet air temperature is maintained at 75.00℃.

[0067] Comparative Example 4: Basically the same as Example 1, except that the coating treatment temperature in step S4 is adjusted to 75.00℃, the mass ratio of apple pomace to deionized water in step A1 is maintained at 1:6.00, the pH of acid-heat extraction in step A2 is maintained at 2.20, the acid-heat extraction temperature in step A3 is maintained at 70.00℃ and the acid-heat extraction time is maintained at 60.00 min, the solid content of apple-derived pectin extract in step A5 is maintained at 1.00 wt%, the pH of washing solution in step B1 is maintained at 3.00, the solid content of wet grinding pulp in step B3 is maintained at 5.00 wt%, the D50 of apple-derived insoluble dietary fiber in step B4 is maintained at 20.00 μm, the dry basis mass ratio in step S2 is maintained at 1:0.20, the pH in step S3 is maintained at 3.20, the coating time in step S4 is maintained at 30.00 min, the solid content of coated pulp in step S5 is maintained at 10.00 wt%, the inlet air temperature of spray drying is maintained at 150.00℃, and the outlet air temperature is maintained at 75.00℃.

[0068] Comparative Example 5: Essentially the same as Example 1, except that in step S3 only citric acid monohydrate was added, not sodium citrate dihydrate, and the pH of the system was adjusted to 3.20. In step A1, the mass ratio of apple pomace to deionized water was maintained at 1:6.00. In step A2, the pH of the acid-heat extraction was maintained at 2.20. In step A3, the acid-heat extraction temperature was maintained at 70.00℃ and the acid-heat extraction time was maintained at 60.00 min. In step A5, the solid content of the apple-derived pectin extract was maintained at 1.00 wt%. Step B1: The pH of the washing solution is maintained at 3.00. Step B3: The solid content of the wet milling pulp is maintained at 5.00 wt%. Step B4: The D50 of the apple-derived insoluble dietary fiber is maintained at 20.00 μm. Step S2: The dry basis mass ratio is maintained at 1:0.20. Step S4: The coating temperature is maintained at 40.00℃ and the coating time is maintained at 30.00 min. Step S5: The solid content of the coated pulp is maintained at 10.00 wt%, the spray drying inlet air temperature is maintained at 150.00℃, and the outlet air temperature is maintained at 75.00℃.

[0069] Comparative Example 6: Essentially the same as Example 1, except that in step S3 only sodium citrate dihydrate was added, not citric acid monohydrate, and the pH of the system was adjusted to 3.20. In step A1, the mass ratio of apple pomace to deionized water was maintained at 1:6.00. In step A2, the pH of the acid-thermal extraction was maintained at 2.20. In step A3, the acid-thermal extraction temperature was maintained at 70.00℃ and the extraction time at 60.00 min. In step A5, the solid content of the apple-derived pectin extract was maintained at 1.00 wt%. Step B1: The pH of the washing solution is maintained at 3.00. Step B3: The solid content of the wet milling pulp is maintained at 5.00 wt%. Step B4: The D50 of the apple-derived insoluble dietary fiber is maintained at 20.00 μm. Step S2: The dry basis mass ratio is maintained at 1:0.20. Step S4: The coating temperature is maintained at 40.00℃ and the coating time is maintained at 30.00 min. Step S5: The solid content of the coated pulp is maintained at 10.00 wt%, the spray drying inlet air temperature is maintained at 150.00℃, and the outlet air temperature is maintained at 75.00℃.

[0070] Comparative Example 7: Basically the same as Example 1, except that in step S5, spray drying was replaced with hot air box drying. The hot air box drying temperature was 80.00℃ and the drying time was 8.00h. After drying, the product was pulverized and sieved. In step A1, the mass ratio of apple pomace to deionized water was maintained at 1:6.00. In step A2, the pH of acid-heat extraction was maintained at 2.20. In step A3, the acid-heat extraction temperature was maintained at 70.00℃ and the acid-heat extraction time was maintained at 60.00min. In step A5, the solid content of apple-derived pectin extract was maintained at 1.00wt%. In step B1, the pH of washing solution was maintained at 3.00. In step B3, the solid content of wet grinding pulp was maintained at 5.00wt%. In step B4, the D50 of apple-derived insoluble dietary fiber was maintained at 20.00μm. In step S2, the dry basis mass ratio was maintained at 1:0.20. In step S3, the pH was maintained at 3.20. In step S4, the coating temperature was maintained at 40.00℃ and the coating time was maintained at 30.00min.

[0071] Comparative Example 8: Basically the same as Example 1, except that in step B4 the D50 of apple-derived insoluble dietary fiber in the apple-derived insoluble dietary fiber pulp is controlled to be 150.00 μm, in step A1 the mass ratio of apple pomace to deionized water is maintained at 1:6.00, in step A2 the pH of acid-heat extraction is maintained at 2.20, in step A3 the acid-heat extraction temperature is maintained at 70.00℃ and the acid-heat extraction time is maintained at 60.00 min, in step A5 the solid content of apple-derived pectin extract is maintained at 1.00 wt%, in step B1 the pH of washing solution is maintained at 3.00, in step B3 the solid content of wet grinding pulp is maintained at 5.00 wt%, in step S2 the dry basis mass ratio is maintained at 1:0.20, in step S3 the pH is maintained at 3.20, in step S4 the coating temperature is maintained at 40.00℃ and the coating time is maintained at 30.00 min, in step S5 the solid content of coated pulp is maintained at 10.00 wt%, the spray drying inlet air temperature is maintained at 150.00℃ and the outlet air temperature is maintained at 75.00℃.

[0072] Comparative Example 9: Basically the same as Example 1, except that apple-derived pectin extract was not added. Powder was prepared only from apple-derived insoluble dietary fiber pulp, citric acid monohydrate, and sodium citrate dihydrate. In step A1, the mass ratio of apple pomace to deionized water was maintained at 1:6.00. In step A2, the pH of acid-heat extraction was maintained at 2.20. In step A3, the acid-heat extraction temperature was maintained at 70.00℃ and the acid-heat extraction time was maintained at 60.00 min. In step B1, the pH of the washing solution was maintained at 3.00. In step B3, the solid content of the wet milling pulp was maintained at 5.00 wt%. In step B4, the D50 of apple-derived insoluble dietary fiber was maintained at 20.00 μm. In step S3, the pH was maintained at 3.20. In step S4, the coating temperature was maintained at 40.00℃ and the processing time was maintained at 30.00 min. In step S5, the solid content of the coated pulp was maintained at 10.00 wt%, the spray drying inlet air temperature was maintained at 150.00℃, and the outlet air temperature was maintained at 75.00℃. This comparative example was used to examine the synergistic relationship between apple-derived insoluble dietary fiber and apple-derived pectin.

[0073] Comparative Example 10: Essentially the same as Example 1, except that apple-derived insoluble dietary fiber pulp was not added. Powder was prepared solely using apple-derived pectin extract, citric acid monohydrate, and sodium citrate dihydrate. In step A1, the mass ratio of apple pomace to deionized water was maintained at 1:6.00; in step A2, the pH of the acid-heat extraction was maintained at 2.20; in step A3, the acid-heat extraction temperature was maintained at 70.00℃ and the extraction time at 60.00 min; in step A5, the solid content of the apple-derived pectin extract was maintained at 1.00 wt%; in step S3, the pH was maintained at 3.20; in step S4, the treatment temperature was maintained at 40.00℃ and the treatment time at 30.00 min; and in step S5, the pulp solid content was maintained at 10.00 wt%, the spray drying inlet air temperature was maintained at 150.00℃, and the outlet air temperature was maintained at 75.00℃. This comparative example was used to investigate the synergistic relationship between apple-derived insoluble dietary fiber and apple-derived pectin.

[0074] Comparative Example 11: Basically the same as Example 1, except that the direct aqueous phase mixing in step S2 was replaced by first spray-drying the apple-derived pectin extract to prepare apple-derived pectin powder, then mixing the apple-derived pectin powder with apple-derived insoluble dietary fiber slurry. The dry weight ratio of apple-derived insoluble dietary fiber to apple-derived pectin was maintained at 1:0.20. The weight ratio of apple pomace to deionized water in step A1 was maintained at 1:6.00. The pH of acid-heat extraction in step A2 was maintained at 2.20. The acid-heat extraction temperature in step A3 was maintained at 70.00℃ and the acid-heat extraction time was maintained at 60.00 min. The solid content of the apple-derived pectin extract in step A5 was maintained at 1.00 wt%. The pH of the washing solution in step B1 was maintained at 3.00. The solid content of the wet-milled slurry in step B3 was maintained at 5.00 wt%. The D50 of the apple-derived insoluble dietary fiber in step B4 was maintained at 20.00 μm. Step S3... The pH was maintained at 3.20, the coating temperature in step S4 was maintained at 40.00℃, the coating time was maintained at 30.00 min, and the solid content of the coated slurry in step S5 was maintained at 10.00 wt%, the spray drying inlet air temperature was maintained at 150.00℃, and the outlet air temperature was maintained at 75.00℃. This comparative example was used to investigate the synergistic relationship between direct aqueous phase mixing and in-situ coating structure.

[0075] Characterization and performance testing: Using the fiber-rich pectin products from Examples 1-4 and all comparative examples as test subjects, the total dietary fiber content was determined. The purpose was to evaluate whether the dry basis composition formed by apple-derived insoluble dietary fiber and apple-derived pectin met the requirements for fiber fortification. The test was conducted according to GB 5009.88-2023 "National Food Safety Standard - Determination of Dietary Fiber in Food". After homogenization, the sample powder was measured in triplicate, and the average and standard deviation of the total dietary fiber content were recorded. The unit is g / 100g, and the results are based on the original mass of the product. Values ​​within the specified range and low dispersion of parallel samples indicate a relatively stable total dietary fiber level in the product.

[0076] Using powder samples from Examples 1-4 and all comparative examples as test objects, D10, D50, and D90 were measured to evaluate the particle size and batch-to-batch consistency of composite particles after spray drying, granulation, and sieving. The tests were conducted according to GB / T 19077-2024 "Particle Size Analysis - Laser Diffraction Method," using deionized water as the dispersion medium, ultrasonic dispersion for 60 seconds, and the shading rate controlled within the instrument's recommended range. Each sample was measured in triplicate. The average D50, standard deviation of D50, and the coefficient of variation between batches of D50 for three consecutive batches were recorded, in μm and %. A D50 within the target range and a low coefficient of variation between batches indicate good particle size stability.

[0077] Using fiber-rich pectin products from Examples 1-4 and all comparative examples as test subjects, moisture content and water activity were determined to evaluate the storage stability of the powder. Moisture content was determined according to GB 5009.3-2016 "National Food Safety Standard - Determination of Moisture in Food". Water activity was measured using a water activity meter at 25°C, with each sample measured in triplicate. The mean moisture content, standard deviation of moisture content, mean water activity, and standard deviation of water activity were recorded. Moisture content and water activity within the target range indicated a low storage risk.

[0078] Using aqueous dispersions with a mass fraction of 1.00 wt% from Examples 1-4 and all comparative examples as test subjects, pH, floc retention rate, and dispersion stability were evaluated to address the trade-off between fiber reinforcement and dispersion stability. 1.00 g of sample was added to 99.00 g of deionized water and stirred at 25°C and 300 rpm for 5 min, and the pH was measured. The sample was then passed through an 180 μm sieve, and the residue was dried at 60°C to constant weight, and the floc retention rate was calculated as the ratio of the dry weight of the residue to the initial dry weight of the sample. After standing for 30 min, the settling height ratio was recorded, which was the ratio of the height of the settling layer to the initial liquid column height of the dispersion system. The average pH, floc retention rate, and settling height ratio were recorded. A lower floc retention rate and a lower settling height ratio indicated better dispersion stability.

[0079] Using the composite particles from Examples 1-4 and all comparative examples as test objects, the coating rate of apple-derived pectin on apple-derived insoluble dietary fiber was determined to evaluate the in-situ coating structure. Samples were weighed, and free apple-derived pectin was eluted with deionized water at 25°C. The solid phase was collected by centrifugation, and the quantifiable pectin content in the solid phase before and after elution was measured. The particle surface coverage area ratio was statistically analyzed using microscopic images. Each sample was measured in triplicate, and the average and standard deviation of the coating rate were recorded as a percentage (%). A coating rate within the target range and low dispersion indicated a relatively stable coating process. The coating rate is defined as the percentage of quantifiable apple-derived pectin mass in the solid phase after elution to the quantifiable apple-derived pectin mass in the solid phase before elution. The particle surface coverage area ratio statistically analyzed by microscopic images served as an auxiliary verification indicator.

[0080] Using the 1.00 wt% aqueous dispersion systems of Examples 1-4 and all comparative examples as test subjects, the apparent viscosity and hydration stability were determined to evaluate the hydration performance of pectin and its suitability for powder reconstitution. After preparation at 1.00 wt%, the samples were stirred at 25°C and 300 rpm for 10 min, then allowed to stand for 10 min. The viscosity was then measured using a rotational rheometer or rotational viscometer at 25°C and a shear rate of 50 s⁻¹. -1 Apparent viscosity was measured under the specified conditions. Each sample was measured in triplicate, and the average and standard deviation of the apparent viscosity were recorded in mPa·s. The pectin hydration and fiber dispersion were assessed in conjunction with the hard agglomerate sieve residue rate.

[0081] Using the preparation processes of Examples 1-4 and all comparative examples as examples, the process yield and pH stability were determined to evaluate the process stability of in-situ aqueous coating and spray drying. The dry basis solids mass of the input product and the dry basis mass of the resulting product were recorded for each batch, and the process yield was calculated. During the coating process, pH was measured every 10 minutes, and the difference between two adjacent pH measurements was calculated. At least three batches were prepared for each group, and the average process yield, standard deviation, and pH difference were recorded. A process yield within the target range and a small pH difference indicated good process stability. The process yield is the ratio of the dry basis mass of the resulting product to the dry basis solids mass of the input product; the pH difference is the absolute value of the difference between two adjacent pH measurements.

[0082] To verify the improvement effects of the fiber-rich pectin product and its preparation method described in this invention on the problems of decreased dispersion stability, mutual restriction between the increased pectin coating degree and the dietary fiber fortification function, and impaired pectin thickening performance after drying and storage in a high-proportion apple-derived insoluble dietary fiber system, the particle size stability, acidity stability during coating process, water activity, rheological properties, hard agglomerate sieve residue rate, pectin dosage response, macroscopic powder state, and microstructure and elemental distribution of Example 1 and related comparative examples were evaluated.

[0083] First, an evaluation is conducted from the perspectives of process repeatability and coating environment stability. Figure 1 This is a dot plot of the D50 batch-to-batch coefficient of variation of the present invention. Figure 1 As can be seen, the inter-batch coefficient of variation of D50 in Example 1 is about 12.0%, which is lower than that of Comparative Example 8 (about 15.8%) and Comparative Example 11 (about 18.0%). Figure 1 The data shown are the D50 coefficients of variation between three consecutive batches of production samples. This result indicates that, under the same or similar preparation systems, the median particle size of the composite particles obtained in Example 1 exhibits smaller batch-to-batch fluctuations, suggesting more stable control over particle size during the pulverization, coating, and drying processes, and demonstrating better process repeatability. For pectin products rich in insoluble dietary fiber, the stability of particle size distribution directly affects subsequent hydration, suspension, and redispersion behavior; therefore… Figure 1 The results demonstrate from a process perspective that the present invention has the foundation for the stable preparation of composite particles.

[0084] Based on the above-mentioned particle size stability, the influence of acid and alkali environment on the formation of composite interface during the coating process was further investigated. Figure 2 This is a pH change curve during the coating process of this invention. (From...) Figure 2As can be seen, within the same coating time range, the pH of Example 1 remained essentially stable at around 3.20; in contrast, the pH of Comparative Example 5 increased to approximately 3.48 over time, while the pH of Comparative Example 6 decreased to approximately 2.91. This result indicates that Example 1, by adjusting the acidity of the system using citric acid monohydrate and sodium citrate dihydrate, can create a relatively stable weakly acidic environment during the coating process. This is beneficial for maintaining the hydration state, molecular conformation, and interaction between apple-derived pectin and the surface and pore structure of apple-derived insoluble dietary fiber. Compared to the comparative examples where the pH increased or decreased significantly, Example 1 is more effective in avoiding problems such as fluctuations in pectin binding state, localized flocculation, or uneven coating, demonstrating that stable pH conditions are an important factor in obtaining a uniform coating structure and controllable composite particles.

[0085] Based on stable processes and controllable coating environment, further evaluate the low moisture storage adaptability of the dried product and its structural support capability after redispersement. Figure 3 This is a graph showing the combined evaluation of water activity and apparent viscosity according to the present invention. Figure 3 As can be seen, the water activity of Example 1 is approximately 0.20, and the apparent viscosity is approximately 185 mPa·s; while the water activity of Comparative Example 7 is approximately 0.39, and the apparent viscosity is approximately 120 mPa·s. These results indicate that Example 1 achieves a lower water activity while maintaining a higher apparent viscosity, suggesting better storage stability after drying, and the ability to form an effective hydration thickening and suspension support structure after rehydration or redispersement. Therefore, this invention does not simply reduce moisture or simply increase viscosity, but rather achieves a better balance between low-moisture storage stability and pectin hydration thickening performance.

[0086] To further illustrate how this viscosity advantage is maintained under actual shear conditions, Figure 4 The viscosity-shear rate process curve of the present invention is shown. As the shear rate increases from 1 s⁻¹... -1 Increased to 200s -1 The apparent viscosity of both Example 1 and Comparative Example 7 showed a decreasing trend, exhibiting typical shear-thinning characteristics, indicating that both belong to dispersed systems with structural network characteristics. Specifically, at 50s... -1 At that time, the apparent viscosity of Example 1 was approximately 185 mPa·s, significantly higher than that of Comparative Example 7 (approximately 120 mPa·s). This result indicates that under actual shear conditions such as simulated stirring, pumping, mixing, or food processing, Example 1 can still maintain strong structural support, which is beneficial for inhibiting the sedimentation and particle aggregation of insoluble dietary fiber, thereby improving the problem of insufficient dispersion stability that is common in high-fiber systems.

[0087] Corresponding to rheological properties, Figure 5 This is a scatter plot showing the hard agglomerate residue rate of the present invention. Figure 5As can be seen, the hard clumping residue rate of Example 1 was approximately 5.0 wt%, significantly lower than that of Comparative Example 8 (approximately 8.8 wt%), Comparative Example 9 (approximately 12.0 wt%), and Comparative Example 11 (approximately 9.0 wt%). A lower hard clumping residue rate indicates fewer coarse hard clumps, non-dispersible residues, and secondary agglomerates in the product. This result demonstrates that the present invention, through synergistic control of coating, particle size, and drying conditions, can effectively reduce the tendency for hard clumping formation common in systems rich in insoluble dietary fiber, thereby improving the uniformity and ease of use of the rehydrated product. Figure 3 and Figure 4 It can be seen that Example 1 not only maintained a high viscosity under low moisture conditions, but also did not suffer from severe hardening due to increased viscosity, proving that it achieved a balance between thickening stability and redispersibility.

[0088] To further clarify the impact of pectin dosage on coating integrity and clumping control, Figure 6 This diagram illustrates the effect of the dry weight ratio of apple-derived pectin to apple-derived insoluble dietary fiber on the coating rate and the residue rate of hard clumps. The experiment used the basic process of Example 1 as a baseline, keeping the coating temperature, fiber D50, spray drying conditions, and other additive dosages constant, only changing the dry weight ratio of apple-derived pectin to apple-derived insoluble dietary fiber. Figure 6 The data in this example comes from the single-factor test samples mentioned above and does not correspond to the sample from Example 2 with different process conditions. Figure 6 It is evident that when the dry weight ratio of apple-derived pectin to apple-derived insoluble dietary fiber increased from 0.10 to 0.69, the coating efficiency increased from approximately 38.0% to approximately 95.0%, while the hard agglomerate residue decreased from approximately 8.2 wt% to approximately 0.3 wt%. This change indicates that appropriately increasing pectin helps form a more continuous coating layer on the surface and within the pores of apple-derived insoluble dietary fiber, thereby reducing fiber exposure, strong direct overlap between particles, and hard agglomerate residue after drying. Further increasing the dry weight ratio of apple-derived pectin to apple-derived insoluble dietary fiber to 0.85 resulted in limited improvement in coating efficiency and hard agglomerate residue, suggesting that excessive pectin does not consistently provide a proportional performance improvement; instead, it may increase costs, raise the viscosity load of the system, and weaken the high-fiber fortification characteristics. Therefore, controlling the dry weight ratio of apple-derived pectin to apple-derived insoluble dietary fiber within a moderate range is more conducive to balancing coating integrity, dispersion stability, and dietary fiber fortification function. This proves that the present invention does not rely on excessive pectin to unilaterally improve stability, but rather achieves synergy between the two types of functional components through reasonable proportioning.

[0089] Regarding the macroscopic powder state, Figure 7 This is a macroscopic optical photograph comparison between the final product of Example 1 and the final product of Comparative Example 7, used to compare the effects of different drying and shaping methods on the powder state of fiber-rich pectin products. Figure 7(a) is a macroscopic optical photograph of the final product of Example 1. This sample is a fiber-rich pectin powder obtained by spray drying. On a dry basis, it contains 83.17 wt% apple-derived insoluble dietary fiber and 16.63 wt% apple-derived pectin. The final composite particle size (D50) is 30.00 μm, the moisture content is 4.00 wt%, the water activity is 0.20, and the hard agglomerate residue is 5.00 wt%. These parameters indicate that even with a high insoluble dietary fiber content, Example 1 can still form a composite powder with low moisture content, low water activity, a hard agglomerate residue within the specified range, and a suitable particle size. Figure 7 (b) is a macroscopic optical photograph of the final product of Comparative Example 7, which is a powder obtained by drying a similar coated slurry in a hot air chamber at 80.00℃ for 8.00h and then pulverizing and sieving. Compared with Example 1, Comparative Example 7 exhibits irregular fragmentation, local agglomeration, and decreased powder uniformity, indicating that simple hot air drying followed by pulverization is insufficient to fully maintain the original uniform composite structure of the coated slurry. Therefore, the aqueous coating combined with spray drying molding route used in Example 1 is beneficial for simultaneously completing granulation and structural fixation during the drying process, demonstrating macroscopic suitability for preparing low-moisture storage-type fiber-rich pectin composite powders.

[0090] Furthermore, Figure 8 The images show the SEM morphology and SEM-EDS surface scan comparison of the final product of Example 1 and the final product of Comparative Example 7. These images are used to assist in evaluating the morphology and component distribution of the composite particles of the present invention from four aspects: overall particle distribution, single particle morphology, surface microstructure, and elemental spatial distribution. Figure 8 (a) is a low-magnification SEM image of the final product of Example 1, showing that the spray-dried powder has a relatively clear micron-level particle size characteristic, which corresponds to the final composite particle D50 of 30.00 μm and 180 μm sieve results. This indicates that the obtained powder is not formed by simply crushing large pieces of dried material, but by forming relatively independent composite particles through the spraying process. Figure 8 (b) is a low-magnification SEM image of the final product of Comparative Example 7, whose overall morphology is used to compare the irregular fragments, compacted agglomerates, and uneven particle distribution observed in the powder after hot air box drying and pulverization. Figure 8 (a) and Figure 8 As can be seen from the comparison in (b), spray drying is more conducive to obtaining powder structures with uniform morphology and good dispersibility.

[0091] Regarding the local morphology of the particles, Figure 8 (c) is a medium magnification SEM image of the final product of Example 1, in which the outline of composite particles with a D50 of about 30.00 μm can be observed. This morphology corresponds to the particle basis of apple-derived insoluble dietary fiber with a D50 of 20.00 μm after wet grinding, and can be used as a morphology reference for the composite particles formed after the coated slurry is spray-dried. Figure 8 (d) is a medium-magnification SEM image of the final product of Comparative Example 7, showing the local morphology of the particles or fragments after hot air drying and pulverization. This illustrates that the route of drying and then pulverizing the bulk material is unlikely to form the same spray-particle structure as in Example 1. Therefore, Figure 8 (c) and Figure 8 (d) This further demonstrates that the spray drying in Example 1 not only serves to dehydrate, but also has the functions of shaping and fixing the composite particles.

[0092] Regarding surface microstructure, Figure 8 (e) is a high-magnification SEM image of the final product of Example 1, showing microstructures such as wrinkles, pores, and the edges of fibrous particles on the particle surface. Combined with the result of a pectin coating rate of 60.00% in stage S4, this morphological result is consistent with the distribution of apple-derived pectin on the surface and in the pores of apple-derived insoluble dietary fiber, but it is not used as the sole basis for confirming the in-situ coating structure. Figure 8 (f) is a high-magnification SEM image of the final product of Comparative Example 7. Its surface exhibits compaction, cracks, flaky fractures, or localized collapse structures, indicating that prolonged heating and bulk water loss during hot air drying can easily lead to damage to the composite interface or uneven structure. Therefore, the combination of aqueous coating and spray drying in this invention is beneficial for maintaining the continuity of the pectin-fiber composite interface and the effective structure of the particle surface.

[0093] Regarding the spatial distribution of elements, Figure 8 (g) is a SEM-EDS surface scan of the final product of Example 1, showing that C, O, and Na elements have spatial distribution characteristics in the composite powder particle region corresponding to the morphology of the sprayed composite particles. Among them, the spatial distribution of Na element can be used as an auxiliary reference for the distribution state of sodium citrate-related components in the powder; C and O elements, since they are present in the carbohydrate backbone of apple-derived insoluble dietary fiber and apple-derived pectin, are only used as auxiliary references for the overall distribution of organic matter and are not used alone to prove the existence or uniformity of the apple-derived pectin coating layer. Figure 8 (h) is a SEM-EDS surface scan of the final product of Comparative Example 7, used for comparison with... Figure 8 (g) Compare the spatial distribution of elements in particles under different drying and forming methods. Through... Figure 8 (g) and Figure 8 The comparison of (h) can serve as an auxiliary reference for comparing the spatial distribution of components under different drying and forming methods.

[0094] In conclusion, Figures 1 to 8The results, reflected in process repeatability, coating acidity stability, low moisture storage capacity, viscosity retention under shear conditions, clumping control, pectin dosage response, macroscopic powder state, and microscopic composite structure, demonstrate that this invention achieves stable particle size, effective coating, low water activity, high viscosity retention, and low clumping residue in composite powders with high insoluble dietary fiber content by in-situ coating of apple-derived pectin on the surface and pores of apple-derived insoluble dietary fiber, combined with citric acid monohydrate and sodium citrate dihydrate to adjust acidity, and by using appropriate drying and shaping methods. This indicates that the invention effectively alleviates the contradiction between the decreased dispersion stability caused by increasing the proportion of insoluble dietary fiber, the potential impact of increased pectin coating degree on dietary fiber fortification function, and the weakening of pectin thickening performance during drying and storage, achieving a synergistic balance between fiber fortification and pectin stabilization functions.

[0095] Table 1 Performance of Examples and Comparative Examples

[0096] As can be seen from the performance of the examples and comparative examples in Table 1, Examples 1–4 show a relatively balanced trend in terms of total dietary fiber content, coating rate, hard agglomerate residue, water activity, apparent viscosity, and process yield. In the conventional comparative examples, deviations in pectin ratio, coating temperature, acidity adjustment components, drying method, or fiber particle size resulted in adverse changes in hard agglomerate residue, coating rate, or process yield. In the synergistic comparative examples, removing apple-derived pectin, removing apple-derived insoluble dietary fiber, or disrupting the direct aqueous phase mixing method made it difficult to simultaneously maintain fiber strengthening function and dispersion stability.

[0097] 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 fiber-rich pectin product, characterized in that, The fiber-rich pectin product includes apple-derived insoluble dietary fiber-apple-derived pectin in situ coated composite particles. Based on a dry basis total mass of 100.00 wt% of the fiber-rich pectin product, the fiber-rich pectin product comprises: Apples contain 58.00-83.17 wt% insoluble dietary fiber. Apple-derived pectin: 16.33-40.00 wt%; The total content of citric acid monohydrate and sodium citrate dihydrate is 0.20-2.00 wt%; The apple-derived insoluble dietary fiber, apple-derived pectin, citric acid monohydrate, and sodium citrate dihydrate are all final form components of the fiber-rich pectin product, and their combined dry basis mass percentage is 100.00 wt%; the dry basis mass ratio of the apple-derived insoluble dietary fiber to the apple-derived pectin is 1:0.20 to 1:0.

69. In the apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles, the apple-derived pectin is distributed on the surface and in the pores of the apple-derived insoluble dietary fiber, forming an in-situ coated structure. The D50 of the apple-derived insoluble dietary fiber-apple-derived pectin in situ coated composite particles is 30.00-180.00 μm, the coating rate of the apple-derived pectin to the apple-derived insoluble dietary fiber is 60.00-95.00%, and the coating rate is the percentage of the mass of quantifiable apple-derived pectin in the solid phase after elution to the mass of quantifiable apple-derived pectin in the solid phase before elution.

2. The fiber-rich pectin product according to claim 1, characterized in that, The mass ratio of the citric acid monohydrate to the sodium citrate dihydrate is 3:

2.

3. The fiber-rich pectin product according to claim 1, characterized in that, The total dietary fiber content of the fiber-rich pectin product is 60.00-85.00g / 100g, and the total dietary fiber content is determined according to GB 5009.88-2023, based on the original sample weight of the fiber-rich pectin product; the moisture content of the fiber-rich pectin product is 4.00-10.00wt%, and the water activity at 25.00℃ is 0.20-0.

60.

4. The fiber-rich pectin product according to claim 1, characterized in that, The apple-derived pectin extract used to prepare the apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles was prepared through the following steps: A1. Mix apple pomace with deionized water, wherein the mass ratio of apple pomace to deionized water is 1:6.00-1:15.00; A2. Add citric acid monohydrate to the mixture obtained in step A1 to adjust the pH to 2.20-3.20; A3. Extract at 70.00-85.00℃ and normal pressure for 60.00-120.00 min to obtain acid-heated extract; A4. The acid-heated extract is subjected to solid-liquid separation to obtain a liquid phase and a solid residue, wherein the liquid phase is the apple-derived pectin extract; A5. Adjust the solid content of the apple-derived pectin extract to 1.00-8.00 wt%; The pH of the apple-derived pectin extract is 2.20-3.

20.

5. The fiber-rich pectin product according to claim 4, characterized in that, The apple-derived insoluble dietary fiber pulp used to prepare the apple-derived insoluble dietary fiber-apple-derived pectin in-situ coated composite particles is prepared through the following steps: B1. Take the solid residue obtained in step A4 and wash it with deionized water until the pH of the washing solution is 3.00-5.50; B2. The washed solid residue is wet-milled to obtain a wet slurry; B3. Adjust the solid content of the wet grinding slurry to 5.00-15.00 wt%; B4. Control the D50 of apple-derived insoluble dietary fiber in the wet pulp to be 20.00-100.00 μm to obtain the apple-derived insoluble dietary fiber pulp; The mass fraction of coarse particles in the apple-derived insoluble dietary fiber pulp that were not dispersed by wet milling is 0.00-5.00 wt%.

6. The fiber-rich pectin product according to claim 1, characterized in that, The water dispersion system of the fiber-rich pectin product with a mass fraction of 1.00 wt% was stirred at 300 rpm for 5.00 min at 25.00 °C with a pH of 3.20-4.80 and a hard agglomerate residue rate of 0.00-5.00 wt%, which was determined using an 180 μm sieve.

7. A method for preparing a fiber-rich pectin product as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Provides apple-derived pectin extract and apple-derived insoluble dietary fiber pulp; S2. Apple-derived insoluble dietary fiber in apple-derived insoluble dietary fiber pulp and apple-derived pectin in apple-derived pectin extract are mixed according to the dry basis mass ratio of apple-derived insoluble dietary fiber to apple-derived pectin, with the dry basis mass ratio of apple-derived insoluble dietary fiber to apple-derived pectin being 1:0.20 to 1:0.

69. S3. Add citric acid monohydrate and sodium citrate dihydrate to the mixture obtained in step S2, and adjust the pH to 3.20-4.20; S4. Stir the mixture obtained in step S3 at 40.00-65.00℃ and normal pressure for 30.00-90.00 min to obtain a coated slurry; at the end of the coating treatment, the difference between two adjacent pH measurements taken at 10.00 min intervals is 0.00-0.20, and the coating rate of the apple-derived pectin to the apple-derived insoluble dietary fiber is 60.00-95.00%; S5. Adjust the coating slurry to a solid content of 10.00-25.00 wt% and spray dry it; the inlet air temperature of the spray dryer is 150.00-180.00℃ and the outlet air temperature is 75.00-90.00℃; granulate and sieve the powder obtained from the spray drying to obtain the fiber-rich pectin product.

8. The preparation method according to claim 7, characterized in that, The apple-derived pectin extract provided in step S1 is a liquid phase obtained from the same batch of apple pomace through acid-heat extraction and solid-liquid separation, and the apple-derived insoluble dietary fiber pulp is prepared from the solid residue obtained by the solid-liquid separation.

9. The preparation method according to claim 7, characterized in that, Steps S1 to S4 are all carried out in an aqueous system. In step S2, the apple-derived pectin extract is directly mixed with the apple-derived insoluble dietary fiber pulp.

10. The preparation method according to claim 7, characterized in that, The fiber-rich pectin product obtained in step S5 has a D50 of 30.00-180.00 μm, a moisture content of 4.00-10.00 wt%, and a water activity of 0.20-0.60.

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