Citrus dietary fiber and yeast protein complex, and preparation method and application thereof

Abstract

The application discloses a yeast protein and citrus fiber functional assembly based on a high-pressure homogenization process and a preparation method thereof, and belongs to the field of novel functional feed.The yeast protein and the citrus fiber are subjected to high-pressure homogenization treatment in a liquid phase, so that the small particles of the yeast protein are uniformly adsorbed on the porous structure of the citrus fiber, and when the cumulative particle size distribution number of the self-assembly reaches 90%, the particle size (D90) is less than 500 nm, which is in the submicron level. Subsequently, the biological activity is maximally retained through freeze-drying, and finally, the final product is obtained through high-speed mixing and granulation. Compared with a traditional physical mixture, the assembly prepared by the method has higher protein digestion rate and anti-inflammatory activity, can effectively replace a traditional feed protein source in a specific proportion, and significantly improves the intestinal health of a colonitis model animal. The application realizes dual innovation of a preparation process and application function, and has extremely high industrial application value.

Description

Technical Field

[0001] This invention relates to the field of feed processing technology, specifically to a yeast protein and dietary fiber complex, its preparation method, and its application. Background Technology

[0002] Approximately 40% of citrus production is used for further processing, which generates about 50% waste, including pulp, seeds, and peel. This waste is dried and pulverized to obtain citrus pomace (CP). Citrus pomace is rich in nutrients such as crude protein, dietary fiber, crude fat, calcium, and phosphorus; it also contains many active ingredients such as flavonoids, phenols, and terpenes, which possess certain antioxidant, anti-inflammatory, and antibacterial properties.

[0003] Yeast protein (YP) is a protein produced through fermentation using renewable raw materials. It has advantages such as high production efficiency and low carbon dioxide emissions. It alleviates the problem of protein resource scarcity to some extent. By partially replacing traditional proteins in food, yeast protein can regulate animal gut health and improve immunity. It has many applications in livestock and aquatic animal production as well as in human health foods.

[0004] Studies on the nutritional functions of citrus pomace have shown that appropriate addition can improve animal growth performance or lipid metabolism. However, its utilization rate is limited, its added value is low, and its mechanism of action is unclear, resulting in insufficient utilization of the nutrients and active ingredients in citrus pomace. The amount that can be added as a food additive is limited, and excessive amounts can affect palatability and animal appetite. In contrast, the physiological and biochemical performance of yeast protein in different animal experiments demonstrates that yeast protein can serve as a new protein source, improving animal production performance, enhancing immunity and antioxidant capacity to some extent, and increasing animal appetite and palatability. Currently, most commercially available feeds use simple dry mixing or low-temperature drying processes, which suffer from weak inter-component binding, uneven particle size distribution, and easy inactivation of heat-sensitive active ingredients (such as citrus flavonoids and yeast bioactive peptides), leading to low actual bioavailability and an inability to effectively address the increasingly serious intestinal inflammation problems in livestock and poultry. Therefore, developing a preparation process that can achieve submicron-level compounding and perfectly preserve active ingredients is key to achieving antibiotic reduction and substitution and feed functionalization.

[0005] Traditionally, interventions for such intestinal mucosal damage and inflammation have relied heavily on antibiotics or chemical drugs. However, long-term, single-drug interventions can easily lead to increased antibiotic resistance in pathogens, further disrupting the existing intestinal microecology, and also pose potential risks of drug residues and other toxic side effects. Therefore, the industry urgently needs to explore safe and efficient new alternatives. Intervention through natural functional nutrients, especially the use of specific functional protein and dietary fiber combinations (such as yeast protein and bioactive citrus pomace complex), can work synergistically. This natural nutritional intervention strategy can not only improve the body's digestive and absorptive efficiency but also effectively regulate the intestinal microecological environment, inhibit the overexpression of local inflammatory factors, and repair damaged intestinal mucosa, thus demonstrating significant application value in maintaining intestinal homeostasis and rebuilding the immune barrier. Developing such natural complexes with anti-inflammatory and intestinal protective functions is becoming an important breakthrough in the research and development of novel functional feeds and health products. Summary of the Invention

[0006] The purpose of this invention is to provide a yeast protein and dietary fiber complex that enhances digestive capacity and improves gut health, as well as its preparation method and application.

[0007] To achieve the above objectives, the present invention provides a citrus dietary fiber and yeast protein complex that enhances digestive capacity and improves gut health. The complex is assembled from yeast protein and citrus fiber through liquid-phase high-pressure homogenization and freeze-drying processes, and the complex exhibits a submicron-scale composite structure.

[0008] The submicron-level composite described in this invention refers to a composite spatial structure formed by the synergistic effect of yeast protein and citrus fiber under a specific high-pressure homogeneous physical field, resulting in macromolecular depolymerization and intermolecular recombination. When the cumulative particle size distribution of the citrus dietary fiber and yeast protein complex reaches 90%, the corresponding particle size (D90) is at the submicron level, below 500 nm.

[0009] Specifically, the distribution characteristics are as follows:

[0010] (1) After being broken and peeled by high pressure, citrus fibers form a micron-scale three-dimensional network skeleton with high porosity (its characteristic particle size distribution is usually in the range of 1~10 μm).

[0011] (2) After being denatured and expanded by ultra-high pressure, yeast proteins dissociate to form nanoscale protein aggregates or monolayers (their characteristic particle size distribution is usually in the range of 50~500 nm).

[0012] (3) The above-mentioned nanoscale yeast protein particles are uniformly and densely anchored to the surface and internal three-dimensional pores of the micron-scale citrus fiber skeleton through non-covalent bonding methods such as hydrogen bonding, hydrophobic interaction and electrostatic attraction, forming a highly dispersed and highly uniform submicron-scale composite phase structure.

[0013] The raw materials of the complex, by weight, include: 1-10 parts yeast protein powder and 1-10 parts citrus fiber powder.

[0014] In some preferred embodiments, the mass ratio of yeast protein powder to citrus fiber powder is 1-3:1-3, and more preferably 1:1.

[0015] The complex contains ≥43wt% protein and ≤10wt% crude fiber.

[0016] Yeast protein is a protein produced through fermentation using renewable raw materials. It boasts advantages such as high production efficiency and low carbon dioxide emissions, thus alleviating the problem of protein resource scarcity to some extent. Yeast protein can regulate animal gut health and enhance immunity, and currently has numerous applications in livestock and aquatic animal production, as well as in human health food.

[0017] Citrus fiber powder, including citrus pomace, is a general term for the residues left after citrus processing. It is rich in various nutrients, including a complete range of amino acids and multiple minerals. Furthermore, citrus pomace contains many bioactive substances, such as flavonoids, coumarins, phenolic acids, and limonene, which possess antibacterial, anti-inflammatory, antioxidant, and anticancer physiological activities, playing a vital role in protecting animal health and promoting animal growth and development.

[0018] Experiments have shown that the present invention, by combining yeast protein and citrus pulp, has the effect of enhancing protein digestibility and improving antioxidant capacity.

[0019] This invention provides a method for preparing the above-mentioned yeast protein and dietary fiber complex, comprising the following steps: raw material pretreatment, high-pressure homogenization assembly, freeze-drying and curing, high-speed mixing and granulation; specifically including the following steps: (1) Yeast protein powder and citrus fiber powder were subjected to high-pressure homogenization in the liquid phase to induce the two to form a spatial cross-linked structure, and a homogenized emulsion was obtained. (2) The homogeneous emulsion was freeze-dried to obtain the composite powder.

[0020] In step (1), the yeast protein powder and citrus fiber powder are pulverized and passed through a 200-mesh sieve before homogenization, and the ratio of raw materials to pure water in the liquid phase is 1:5 to 1:15. The high-pressure homogenization process is carried out at a pressure of 50 MPa to 150 MPa, and is repeated 2 to 5 times.

[0021] In step (2), the freeze drying is carried out for 36 to 48 hours under conditions where the vacuum degree is less than 10 Pa and the cold trap temperature is not higher than -55°C.

[0022] The preparation steps also include a step of high-speed mixing of the obtained composite powder with the feed matrix and extrusion granulation.

[0023] The feed matrix comprises one or more combinations of energy feed ingredients, protein feed ingredients, and nutritional additives; preferably, the energy feed ingredients are selected from at least one of corn, wheat, or wheat bran, and the protein feed ingredients are selected from at least one of soybean meal, fermented soybean meal, or fishmeal. High-speed mixing refers to mixing for 3 to 15 minutes at a rotation speed of 300 r / min to 1500 r / min using a shear mixing device, so that the compound powder is uniformly dispersed in the feed matrix.

[0024] Another technical solution of the present invention is the application of the functional complex or the functional complex prepared according to the preparation method in the preparation of feed, food or medicine.

[0025] The application is for at least one of the following: increasing protein digestibility, regulating gut microbiota, relieving intestinal inflammation, repairing intestinal mucosal damage, or enhancing antioxidant capacity; The relief of intestinal inflammation includes at least one of improving colonic pathological damage, reducing the disease activity index, and regulating the intestinal immune response; The functional complex replaces traditional protein sources (such as soybean meal or fish meal) in the basal feed at a weight ratio of 20% to 80%.

[0026] The present invention also provides a feed additive or feed nutritional supplement comprising the aforementioned functional compound and feed-acceptable excipients.

[0027] In some embodiments, the complex described in this invention is in the form of powder, granules, blocks, or paste.

[0028] Currently, most commercially available feeds employ simple dry mixing or low-temperature drying processes. These processes suffer from weak inter-component binding, uneven particle size distribution, and easy inactivation of heat-sensitive active ingredients (such as citrus flavonoids and yeast bioactive peptides), resulting in low actual bioavailability and an inability to effectively address the increasingly severe intestinal inflammation problems in livestock and poultry. Therefore, developing a preparation process that can achieve submicron-level compounding while perfectly preserving active ingredients is crucial for realizing antibiotic reduction and substitution, as well as feed functionalization.

[0029] The beneficial effects of this invention are as follows: (1) The high-pressure homogenization-freeze-drying combined process was applied to yeast protein for the first time. The composite system utilizes the cavitation effect generated by high-pressure homogenization to forcibly induce yeast protein molecules to embed into the nanoscale pores of citrus fibers, thus preparing a submicron-scale assembly with stronger stability and higher bioavailability.

[0030] (2) This complex not only provides high-quality protein, but also acts as an intestinal protectant, which can perfectly replace traditional soybean meal protein source at a ratio of up to 20%, ensuring animal growth while significantly reducing dependence on feed drugs (antibiotics).

[0031] (3) In vivo experiments have confirmed that this functional feed can significantly downregulate the inflammatory factors IL-1β / IL-6 and repair the intestinal mucosa. Its effect is far superior to that of traditional physically mixed feed components. Attached Figure Description

[0032] Figure 1 This is a process flow diagram of the yeast protein and citrus fiber complex.

[0033] Figure 2 A diagram illustrating the process and mechanism of action of the yeast protein and citrus fiber complex in enhancing digestive capacity.

[0034] Figure 3 The images show the SEM microstructures of the yeast protein and citrus fiber composite. a is a microscopic image of Example 1, b is a microscopic image of Example 2, c is a microscopic image of Example 3, d is a microscopic image of Comparative Example 1, and e is a microscopic image of Comparative Example 2.

[0035] Figure 4 This is a graph showing the results of protein concentration measurements in digestive fluids during the gastric and intestinal digestive stages.

[0036] Figure 5 This is a graph showing the DPPH free radical scavenging capacity of digestive juices during the gastric and intestinal digestive stages.

[0037] Figure 6 This is a graph showing the total antioxidant capacity of ABTS in digestive juices during the gastric and intestinal digestive stages.

[0038] Figure 7 This is a graph showing the total antioxidant capacity of FRAP in digestive juices during the gastric and intestinal digestive stages.

[0039] Figure 8 This is a graph showing the change in mouse body weight.

[0040] Figure 9 This is a score chart of the Disease Activity Index (DAI) for mice.

[0041] Figure 10 Gross morphology of the colon (a), colon length (b), and spleen weight (c) of each group of mice.

[0042] Figure 11 The images show H&E-stained pathological sections of colon tissue from mice in each group. a is a microscopic image of the blank control group, b is a microscopic image of the model group, c is a microscopic image of Example 1, d is a microscopic image of Example 2, and e is a microscopic image of Example 3.

[0043] Figure 12 The graphs show the detection data of the complex on intestinal inflammatory factors. a is the data of IL-1β, b is the data of IL-6, and c is the data of IL-10. Detailed Implementation

[0044] The technical solution of the present invention will be further described and illustrated below with reference to specific embodiments. For those skilled in the art, the following description of the disclosed embodiments will enable them to implement the present invention. Conditions not specified in the embodiments are performed under conventional conditions. Unless otherwise specified, all instruments and reagents used are products obtained through commercial channels.

[0045] Experimental materials: Yeast protein was purchased from Angel Yeast Co., Ltd., with a protein content of ≥84%; citrus pomace was obtained from Haitong Canned Food Industry Group (citrus peel and pomace waste obtained from citrus canning).

[0046] Yeast protein and dietary fiber complexes of Examples 1-3 and Comparative Examples 1-2 Prepare yeast protein and dietary fiber complexes in different proportions according to the preparation methods in Table 1 and below.

[0047] Example 1: Preparation method of citrus pomace and yeast protein complex: 1. Raw material pretreatment: The yeast protein powder and citrus pulp of the formula amount are pulverized separately and passed through a 200-mesh sieve. Ultrafine pulverization breaks down the original dense structure of the materials, providing sufficient specific surface area for subsequent deep molecular penetration; 2. High-pressure homogenization and assembly: The pulverized raw materials are added to pure water at a material-to-liquid ratio of 1:10, premixed, and then fed into a high-pressure homogenizer. The homogenization process is repeated three times at 100 MPa. Utilizing the high-speed shearing, cavitation effect, and instantaneous pressure drop during high-pressure homogenization, the network structure of the citrus fibers is fully opened, inducing yeast protein molecules to "assemble in situ" within its micropores, forming a stable submicron-sized complex. When the cumulative particle size distribution of the complex reaches 90%, the corresponding particle size (D90) is below 500 nm, which is in the submicron range.

[0048] 3. Freeze-drying and solidification: The homogenized assembly emulsion is pre-frozen at -80℃ and then transferred to a freeze dryer for drying at a vacuum of less than 10 Pa and a cold trap temperature of -55℃ for 36-48 hours. Freeze-drying avoids the thermal damage to the protein spatial conformation caused by traditional hot air drying, forming a loose and porous microstructure, which is conducive to the rapid rehydration of the assembly and the release of active ingredients in the intestine.

[0049] 4. High-speed mixing and granulation: The dried assembly powder is fed into a high-speed mixer and mixed with the synergistic biological laboratory mouse maintenance feed (product number: XTC01WC-001) at a high speed of 3000~5000 rpm. Subsequently, it is extruded into functional pellet feed with a particle size of 2-4 mm using a pellet mill. This process ensures uniform encapsulation of the complex and the feed matrix, improves the physical stability and feed intake of the product, and realizes the application transformation from "laboratory material" to "engineered feed". Figure 2 A diagram illustrating the process and mechanism of action of the yeast protein and citrus fiber complex in enhancing digestive capacity.

[0050] Table 1. Formulations of yeast protein powder and citrus pomace complex in the examples and comparative examples. (Unit: parts by weight)

[0051] Remark: 1. The preparation method of Comparative Example 1 in the table is as follows: Mix the yeast protein powder and citrus pulp powder in the prescribed amount, mix with a common magnetic stirrer at a speed of 2000 rpm, cycle 2 to 5 times, and then carry out the mixture for 36 to 48 hours under the conditions of vacuum degree below 10 Pa and cold trap temperature not higher than -55℃.

[0052] 2. The preparation method of Comparative Example 2 in the table is as follows: the yeast protein powder and citrus pulp powder of the formula amount are mixed, homogenized under high pressure at a pressure of 50 MPa to 150 MPa, and cyclically processed 2 to 5 times. Then, they are dried in an oven at 30 to 50°C for 36 to 48 hours.

[0053] Experiment Example 4 Microstructure of yeast protein and dietary fiber complex Experimental method: The surface microstructure of the composite prepared in Example 1 was observed using a scanning electron microscope and sputtering deposition method with an accelerating voltage of 10 kV. Figure 3 SEM microstructure of yeast protein and citrus fiber composite.

[0054] Experimental Example 5 Evaluation of the efficacy of yeast protein and dietary fiber complex in improving protein digestibility The prepared complex was subjected to in vitro simulated digestion according to "INFOGEST static in vitro simulation of gastrointestinal food digestion" to determine its protein digestibility.

[0055] Experimental methods: 1. Sample processing Take 1g of the complex, add 10mL of pure water, mix thoroughly, and incubate at 37℃ for 5min. Then, perform in vitro simulated digestion of the complex in the gastric and intestinal stages according to the above literature. At the end of the gastric and intestinal digestion stages, boil the sample for 10min to terminate digestion, then centrifuge. Store the supernatant at -80℃ for later analysis, and freeze-dry the precipitate for later analysis.

[0056] 2. Experimental Methods (1) Protein digestibility determination The crude protein content of the samples was determined according to GB / T 6432-2018 Determination of Crude Protein in Feed - Kjeldahl Method, and the protein digestibility was calculated.

[0057] The crude protein content of the complex was measured as m1, the crude protein content after gastric digestion was m2, and the crude protein content after intestinal digestion was m3. The protein digestibility A1 and A2 of the complex during the gastric and intestinal digestion stages were calculated according to the following formula, and the results are shown in Table 2.

[0058] Protein digestibility A1 (%) in the stomach stage = (m1-m2) / m1 100%; Intestinal protein digestibility A2 (%) = (m2 - m3) / m2 100%.

[0059] Table 2. Protein digestibility of yeast protein and dietary fiber complex

[0060] Note: Different letters in the table indicate significant differences in data between groups. P <0.05.

[0061] The results showed that during the gastric digestion stage, the digestibility of the complex in Example 1 was 30.7%, while that in Example 2 was 7.56%, showing a significant difference. P <0.05); The digestibility of Example 3 was 27.81%, with no significant difference ( P>0.05). During the intestinal digestion stage, the protein digestibility of Example 1 was 37.25%, which was higher than that of Comparative Examples 2 and 3. This indicates that the complex formulated in Example 1 exhibits higher protein digestibility in both the gastric and intestinal phases. Furthermore, Example 1 also showed higher protein digestibility in both the gastric and intestinal phases compared to Comparative Examples 1 and 2, suggesting that high-pressure homogenization and freeze-drying promote protein digestion of the complex.

[0062] (2) Determination of protein concentration in digestive juices during the gastric and intestinal digestion stages (BCA method) Collect the supernatant after digestion in the stomach and intestines, and measure the protein concentration according to the instructions of the BCA protein assay kit. The results are as follows: Figure 4 As shown. Figure 4 Determination of protein concentration in digestive juices during the gastric and intestinal digestive stages.

[0063] In Example 1, the protein concentrations in the gastric and intestinal phases were 4.31 mg / ml and 6.54 mg / ml, respectively. Except for being slightly lower than the gastric phase concentration of Example 3 (4.98 mg / ml), the overall concentrations were significantly higher than those of the other examples and comparative examples. This indicates that compared to the different raw material ratios in Examples 1 and 2, the ratio in Example 1 resulted in a superior protein dissolution concentration. Furthermore, compared to Comparative Examples 1 and 2, which did not undergo high-pressure homogenization and freeze-drying (with a maximum concentration not exceeding 2.28 mg / ml), Example 1, which underwent both treatments, facilitated protein dissolution during digestion.

[0064] Experimental Example 6 Antioxidant activity of yeast protein and dietary fiber complex during simulated digestion (1) Determination of DPPH free radical scavenging capacity of digestive juices during gastric and intestinal digestion. a) Preparation of standard solutions and DPPH solutions. Accurately weigh ascorbic acid standard and prepare a series of standard solutions at concentrations of 0.15, 0.3, 0.6, 0.9, 1.2, and 1.5 mM. Accurately weigh DPPH standard, dilute to 1 mM with anhydrous ethanol, store at -20°C protected from light, and dilute 10-fold with pre-cooled ethanol to 0.1 mM immediately before use, and store on ice.

[0065] b) Determination of sample solutions. Add 0.5 mL of 0.1 mM DPPH-ethanol solution and 1.5 mL of the sample to a centrifuge tube, for a total volume of 2.0 mL. After reacting in the dark for 30 min, transfer to a 96-well plate and measure the absorbance using a microplate reader (λ=517 nm, bandwidth 2 nm), recorded as Ai. Add 1.5 mL of 0.1 mM DPPH-ethanol solution and 0.5 mL of water, and record the measured value as A0. Add 1.5 mL of water and 0.5 mL of the sample, and record the measured value as Aj. Perform three parallel experiments. The DPPH free radical scavenging capacity is calculated using the following formula: Clearance (%) = [1 - (Ai - Aj) / A0] × 100% The results are as follows Figure 5 As shown: In the three examples with different formulations, Example 1 exhibited the highest DPPH scavenging rate, reaching 93.45% in the gastric phase and 59.81% in the intestinal phase, indicating stronger antioxidant capacity of the complex. Example 2 was second highest, while Example 3 was the weakest. For Comparative Examples 1 and 2, which had the same formulation as Example 1, the complexes that had not undergone high-pressure homogenization or freeze-drying had even lower DPPH scavenging rates. In the gastric and intestinal phases, Comparative Example 1 showed 80.92% and 42.26%, respectively; while Comparative Example 2 showed 74.71% and 40.58%, respectively. This indicates that when the weight ratio of yeast protein powder to citrus pomace is 1:1, and when high-pressure homogenization and freeze-drying are performed, the DPPH scavenging rate of the complex is stronger.

[0066] (2) Determination of the total antioxidant capacity of ABTS in digestive juices during gastric and intestinal digestion. a) Preparation of standard solutions. Accurately weigh Trolox to prepare a 10 mM stock solution, and then serially dilute it to prepare a series of standard solutions of 0.15, 0.3, 0.6, 0.9, 1.2 and 1.5 mM.

[0067] b) Preparation of ABTS working solution. Prepare 7 mM ABTS+ solution and 2.45 mM potassium persulfate solution, mix 1:1, and let stand in the dark for 12-16 h. Dilute with PBS to an absorbance of 0.7±0.02 (λ=734 nm). Prepare and use immediately.

[0068] c) Sample determination Dilute the sample solution to an appropriate concentration, take 20 μL into a 96-well plate, add 180 μL of ABTS working solution, react in the dark for 30 min, and then measure the absorbance at 734 nm using a microplate reader. The ABTS antioxidant capacity of the sample can be expressed as Trolox-Equivalent Antioxidant Capacity (TEAC) (mM).

[0069] See results Figure 6The attached figure shows the total antioxidant capacity of ABTS in digestive fluids during the gastric and intestinal digestion stages. The results show that the total antioxidant capacity of the complex in Example 1 during the gastric and intestinal digestion stages was 565.37 mM and 452.51 mM, respectively, maintaining a higher level overall compared to Examples 2 and 3. For Comparative Examples 1 and 2, which have the same proportions as Example 1, the ABTS antioxidant capacity of the complexes that were not subjected to high-pressure homogenization or freeze-drying was lower. In the gastric and intestinal stages, Comparative Example 1 showed 482.14 mM and 306.60 mM, respectively; while Comparative Example 2 showed 429.40 mM and 295.58 mM, respectively. This indicates that when the weight ratio of yeast protein powder to citrus pomace is 1:1, and high-pressure homogenization and freeze-drying are performed, the ABTS antioxidant capacity of the complex is stronger.

[0070] (3) Determination of total antioxidant capacity of FRAP in digestive fluids during gastric and intestinal digestion. a) Preparation of standard solutions. Accurately weigh ferrous sulfite to prepare a 100 mM stock solution, which is then serially diluted to prepare a series of standard solutions of 0.15, 0.3, 0.6, 0.9, 1.2 and 1.5 mM.

[0071] b) Preparation of FRAP working solution Mix 0.3M acetate buffer, 20mM ferric chloride solution and 10mM TPTZ solution in a ratio of 10:1:1, incubate at 35°C for 1 hour, and use immediately after preparation.

[0072] c) Add 25 μL of the test solution or standard solution diluted to an appropriate concentration to a 96-well plate, then add 900 μL of FRAP working solution, incubate at 35°C in the dark for 5 min, and measure the absorbance at a wavelength of 593 nm. The total antioxidant capacity of FRAP is expressed as the concentration of FeSO4 standard solution (mM).

[0073] See results Figure 7 The graphs show the total antioxidant capacity of FRAP in digestive fluids during the gastric and intestinal digestion stages. The results indicate that, compared to Examples 2 and 3, the complex in Example 1 exhibited the highest FRAP antioxidant capacity in both the gastric and intestinal stages, at 589.70 mM and 452.51 mM, respectively. This suggests that the complex possesses the strongest FRAP antioxidant capacity when the weight ratio of yeast protein powder to citrus pomace powder is 1:1. Comparative Examples 1 (502.94 mM and 423.23 mM FRAP in the gastric and intestinal stages) and 2 (456.50 mM and 238.27 mM FRAP in the gastric and intestinal stages), which did not undergo high-pressure homogenization or freeze-drying, demonstrate that the complex exhibits even stronger FRAP antioxidant capacity after high-pressure homogenization and freeze-drying.

[0074] Experimental Example 7 The ameliorative effect of yeast protein and dietary fiber complex on colitis model mice (1) Experimental animals and model construction C57BL / 6 mice of a specific age were randomly divided into a normal control group, a model group, and a complex intervention group (DSS + the complex from Example 1). A colitis model was established using the sodium dextran sulfate (DSS) drinking water method. The intervention group was fed the complex diet or administered it by gavage before and after model establishment.

[0075] (2) The effect of the complex on mouse body weight and disease activity index (DAI) was determined by recording the body weight and clinical symptoms of mice in each group during the modeling period (e.g., Figure 8 As shown in the figure, the model group mice exhibited significant stagnation or even decline in weight gain during each round of DSS drinking modeling, accompanied by clinical symptoms such as loose stools, mucus stools, and visible rectal bleeding, and their Disease Activity Index (DAI) scores were significantly elevated. In contrast, mice fed diets containing yeast protein and citrus fiber complexes (Examples 1, 2, and 3) showed a more stable weight gain trend. In particular, the Example 1 intervention group showed a significantly higher rate of weight recovery and final weight gain in the later stages of the experiment compared to the model group, and its diarrhea frequency and rectal bleeding were significantly improved, with a significant decrease in DAI scores. These results indicate that the complex can effectively alleviate the body's wasting and intestinal inflammation symptoms caused by colitis, exhibiting significant intestinal mucosal protection and anti-inflammatory repair effects in vivo (e.g., Figure 8 , 9 (As shown).

[0076] (3) Improvement of colon length and gross morphology in mice with colitis by the complex. Colonic shortening is a typical marker of colitis. Post-dissection observation of the gross morphology of the colon in each group of mice revealed (e.g.) Figure 10 As shown in the figure, the colon length of mice in the model group was significantly shortened compared to the control group, exhibiting obvious characteristics of intestinal damage. However, after intervention with different ratios of yeast protein and citrus fiber complex (Examples 1, 2, and 3), the colon length of mice recovered to varying degrees, tending towards the level of the normal group. Statistical difference analysis showed that the colon length of the intervention group showed an increasing trend compared to the model group, with Example 1 showing the most significant increase in colon length. This demonstrates that the complex with this ratio can effectively inhibit DSS-induced colon shortening and has a significant protective and maintenance effect on colonic tissue.

[0077] (4) The repair effect of the complex on pathological damage in colon tissue was observed by H&E staining of colon tissues from various groups of mice (e.g., Figure 11As shown in the figure, the colonic tissue structure of the blank control group was intact, with neatly arranged crypts and no mucosal damage; the model group showed severe pathological damage, including large-area disappearance of crypt structure, damage to the mucosal epithelium, and obvious inflammatory cell infiltration. In contrast, after intervention with different ratios of yeast protein and citrus fiber complex (Examples 1, 2, and 3), the damage to the colonic tissue was significantly reduced, the crypt structure tended to be intact, the mucosal layer was effectively repaired, and the inflammatory cell infiltration was significantly reduced. Example 1 showed the most significant improvement in colonic tissue morphology, almost indistinguishable from the blank control group. This result intuitively demonstrates that the complex has a significant repair and protective effect on colonic pathological damage.

[0078] (5) IL-1β and IL-1β levels in colon tissue of each group were measured according to the kit instructions. The OD values ​​of IL-6 and IL-10 were determined, and the levels of IL-1β and IL-10 in each group of samples were calculated. The concentrations of IL-6 and IL-10, Figure 12 The levels of IL-1β and IL-1 in colon tissue after treatment with different experimental groups of the composition were compared. Graph showing the concentration results of IL-6 and IL-10.

[0079] Depend on Figure 12 It was found that the concentration of the anti-inflammatory factor IL-10 in the colonic tissue of mice after modeling treatment was significantly lower than that in the blank control group (539.0 g / mL) (43.05 g / mL), indicating that modeling aggravated colonic inflammation in mice. (Example 1) After treatment with the three groups of compositions, the IL levels in mouse serum were [reduced / decreased]. The levels of 10 anti-inflammatory factors were significantly elevated, as shown in Example 1. IL in 3 groups of serum The concentrations of 10 were 721.0 pg / mL, 544.8 pg / mL, and 305.4 pg / mL, respectively, which upregulated the expression level of anti-inflammatory factors, indicating that the diet added in Example 1 had the best resistance to colonic inflammation in mice.

[0080] IL in the model group The levels of 1β and IL-6 inflammatory factors were 710.8 pg / mL and 315.6 pg / mL, respectively, which were significantly higher than those in the blank control group (72.27 pg / mL and 46.82 pg / mL), demonstrating that the model exacerbated intestinal inflammation in mice. (Following Example 1...) After treatment with the combined formula in all three groups, the levels of two inflammatory factors in the tissues were significantly reduced, including IL-12. The 1β concentrations were 96.65 pg / mL, 335.9 pg / mL, and 624.0 pg / mL, respectively, and the IL-6 concentrations were 57.12 pg / mL, 181.1 pg / mL, and 273.4 pg / mL, respectively, indicating that the addition of Example 1 to the diet had the best effect on alleviating colonic inflammation in mice.

[0081] The in vivo experiments described above demonstrate that the yeast protein and dietary fiber complex prepared in this invention not only exhibits good digestibility and antioxidant capacity in vitro, but also serves as an effective functional nutrient in vivo, significantly intervening in and alleviating intestinal inflammation, showcasing its great potential as a novel healthy feed.

Claims

1. A citrus dietary fiber and yeast protein complex that enhances digestion and improves gut health, characterized in that, The complex is assembled from yeast protein and citrus fiber through liquid-phase high-pressure homogenization and freeze-drying processes. The complex exhibits micro-nano distribution characteristics, with the D90 particle size being submicron level below 500 nm.

2. The complex according to claim 1, characterized in that, The raw materials of the complex, by weight, include: 1-10 parts yeast protein powder and 1-10 parts citrus fiber powder.

3. The complex according to claim 2, characterized in that, The complex contains ≥43wt% protein and ≤10wt% crude fiber.

4. A method for preparing a complex according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Yeast protein powder and citrus fiber powder were subjected to high-pressure homogenization in the liquid phase to induce the two to form a spatial cross-linked structure, and a homogenized emulsion was obtained. (2) The homogeneous emulsion was freeze-dried to obtain the composite powder.

5. The preparation method according to claim 4, characterized in that, In step (1), the pressure of the high-pressure homogenization treatment is 50 MPa to 150 MPa, and the treatment is repeated 2 to 5 times. The yeast protein powder and citrus fiber powder are pulverized and passed through a 200-mesh sieve before homogenization. The ratio of raw materials to pure water in the liquid phase is 1:5 to 1:

15.

6. The preparation method according to claim 4, characterized in that, In step (2), the freeze drying is carried out for 36 to 48 hours under conditions where the vacuum degree is less than 10 Pa and the cold trap temperature is not higher than -55°C.

7. The preparation method according to claim 4, characterized in that; It also includes the step of high-speed mixing of the obtained composite powder with the feed matrix and extrusion granulation.

8. The use of the functional complex according to any one of claims 1 to 3 or the functional complex prepared by the preparation method according to any one of claims 4 to 7 in the preparation of feed, food or medicine.

9. The application according to claim 8, characterized in that, The application is for at least one of the following: increasing protein digestibility, regulating gut microbiota, relieving intestinal inflammation, repairing intestinal mucosal damage, or enhancing antioxidant capacity; The relief of intestinal inflammation includes at least one of improving colonic pathological damage, reducing the disease activity index, and regulating the intestinal immune response; The functional complex replaces traditional protein sources in the basal feed at a weight ratio of 20% to 80%.

10. A feed additive, characterized in that, It comprises the functional complex of any one of claims 1 to 3 and feed-acceptable excipients.

Images