Plant extract feed additive for improving pork quality

Abstract

The invention relates to the technical field of livestock feed, in particular to a plant extract feed additive for improving pork quality. The plant extract additive disclosed by the invention contains stevia rebaudiana, folium cortex eucommiae, cortex magnoliae officinalis, marigold, astragalus membranaceus, dandelion and ampelopsis grossedentata extracts which are rich in active substances such as polyphenol, flavonoid compounds and saponin; the active substances can effectively scavenge free radicals, reduce oxidative stress of organisms, reduce muscle lipid oxidation, effectively delay rancidity of pork in the storage process, prolong the shelf life, improve the flavor of meat products and reduce peculiar smell. Different extraction processes are adopted for different plant raw materials, and the stability of active ingredients of the plant extract can be effectively improved. In addition, whey protein is added into the feed additive, so that muscle health and development can be enhanced, and meat tenderness and marbling can be improved.

Description

Technical Field

[0001] This invention relates to the field of livestock feed technology, and in particular to a plant extract feed additive for improving pork quality. Background Technology

[0002] As people's living standards improve, consumers are increasingly demanding higher quality pork, focusing not only on its nutritional value but also on its flavor, tenderness, shelf life, and safety. Currently, most methods for improving pork quality rely on chemical additives. While these may achieve the desired effect to some extent, they pose a risk of residue, potentially harming human health and causing environmental problems.

[0003] Plant extracts, as carriers of natural active substances, are rich in active ingredients such as polyphenols, flavonoids, and saponins. They possess biological functions such as antioxidation, anti-inflammation, and regulation of intestinal flora, and are highly safe with no residue risk, showing broad application prospects in the field of feed additives. However, existing plant extract feed additives lack scientific rationality in their component formulation, and the synergistic effects between components are not significant, making it difficult to fully exert their efficacy in improving pork quality. Furthermore, the preparation process of plant extracts and related excipients suffers from problems such as low extraction efficiency, poor retention rate, insufficient stability, and low bioavailability of active ingredients, limiting their application in actual production.

[0004] Therefore, developing a plant extract feed additive that improves pork quality by combining scientifically formulated ingredients with significant synergistic effects and using a preparation method that effectively enhances the extraction efficiency, retention rate, stability, and bioavailability of active ingredients has become a pressing technical problem in the current feed additive field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing feed additives for improving pork quality, such as poor safety, insignificant synergistic effects of components, low extraction efficiency of active ingredients, poor stability and low bioavailability, and to provide a plant extract feed additive for improving pork quality.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A plant extract feed additive for improving pork quality, comprising the following components by weight: Stevia extract 10-30 parts, Eucommia ulmoides leaf extract 10-50 parts, Magnolia officinalis extract 5-15 parts, Marigold extract 5-20 parts, Astragalus membranaceus extract 10-30 parts, Taraxacum mongolicum extract 20-50 parts, Chaenomeles speciosa extract 20-50 parts, and whey protein 2-5 parts.

[0007] The preparation method of the present invention includes the following steps: S1. Raw Material Preparation Marigold extract, vine tea extract and whey protein were prepared separately, and stevia extract, eucommia leaf extract, magnolia bark extract, astragalus extract and dandelion extract were also prepared. S2. Mixing Process Stevia extract, Eucommia leaf extract, Magnolia officinalis extract, Marigold extract, Astragalus membranaceus extract, Dandelion extract, and Vine tea extract are mixed with whey protein in a specific ratio and stirred thoroughly.

[0008] Preferably, the preparation method of the marigold extract in step S1 includes the following steps: S1-1-1. Pretreatment Marigold flowers were frozen, pulverized, and then vacuum dried. S1-1-2. Single extraction The pretreated material was mixed with the extraction solvent and then subjected to ultrasound-assisted extraction in the presence of a complex enzyme. S1-1-3. Secondary Extraction The filter residue after the first extraction was mixed with the extraction solvent again and subjected to variable amplitude ultrasonic extraction. S1-1-4. Post-processing The combined extracts were then subjected to microfiltration, nanofiltration concentration, and drying to obtain marigold extract. The complex enzyme mentioned in step S1-1-2 is one or more of cellulase, β-glucanase and hemicellulase; The ultrasound-assisted extraction described in step S1-1-2 uses multi-frequency ultrasound, with a low frequency of 20-40kHz and a power of 300-320W, a medium frequency of 50-60kHz and a power of 230-250W, and a high frequency of 100-120kHz and a power of 180-200W. The frequency of the variable-amplitude ultrasound described in step S1-1-3 varies periodically between 30kHz and 50kHz, with a variation period of 1-3 minutes, and the ultrasound power is 380-420W.

[0009] Preferably, the preparation method of the vine tea extract in step S1 includes the following steps: S1-2-1. Freeze the stems and leaves of vine tea, then crush them and pass them through an 80-100 mesh sieve to obtain coarse vine tea powder; S1-2-2. The vine tea raw material is subjected to a first extraction and a first enzymatic hydrolysis with a first enzyme. After the first enzymatic hydrolysis, a first enzyme inactivation treatment is performed to obtain a first extract, and the first extract is concentrated to obtain a concentrated liquid. S1-2-3. The concentrate is subjected to a second enzymatic hydrolysis with a second enzyme, followed by a second enzyme inactivation treatment and a first crystallization treatment to obtain the first crystal; S1-2-4. Add the first adsorbent to perform the second extraction and first decolorization treatment on the first crystal; S1-2-5. Perform a second crystallization process to obtain a second crystal; S1-2-6. Dissolve the second crystal in water to prepare an aqueous solution, and then mix the aqueous solution with the embedding aid and emulsifier by shearing, homogenize three times, and then add the second adsorbent. S1-2-7. The second adsorbent is separated from the filtrate and the filtrate is freeze-dried to obtain a water-soluble vine tea extract; The first extraction is ultrasonic ethanol extraction, the second extraction is heating and pressurizing water extraction, the first enzyme is cellulase and pectinase; the second enzyme is at least one of cellulase, pectinase and α-amylase.

[0010] Preferably, the method for preparing whey protein in step S1 includes: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The inlet air temperature of the low-pressure spray drying process is 60-85℃, the outlet air temperature is 45-60℃, the vacuum degree is 0.02-0.4MPa, and the flow rate is 5-8mL / min.

[0011] 1. The plant extract additive of the present invention contains extracts of stevia, eucommia leaves, magnolia bark, marigold, astragalus, dandelion, and vine tea. All of the above components are rich in active substances such as polyphenols, flavonoids, and saponins. These active substances can effectively scavenge free radicals, reduce oxidative stress in the body, reduce muscle lipid oxidation, effectively delay the rancidity of pork during storage, extend shelf life, improve meat flavor, and reduce off-odors.

[0012] 2. This invention adds whey protein to feed additives, which can enhance muscle health and development, and improve meat tenderness and marbling. The whey protein of this invention is prepared by microfiltration, ultrasonic treatment, and low-pressure spray drying, and has the characteristics of high purity and easy digestibility. It can provide abundant essential amino acids, promote protein synthesis and muscle growth in pigs, and improve feed conversion rate.

[0013] 3. The additives in this invention specifically contain vine tea extract. Vine tea extract is rich in dihydromyricetin, which has significant antioxidant and anti-inflammatory activities, can regulate the balance of intestinal flora, enhance immunity, and promote nutrient absorption, thereby improving the overall health and production performance of pigs. The vine tea extract of this invention uses enzymatic hydrolysis and encapsulation technology, which can effectively improve the release control and absorption rate of flavonoids in the intestine, further enhancing its bioavailability.

[0014] 4. This invention employs different extraction processes for different plant raw materials, which can effectively improve the stability of active ingredients in plant extracts. Specifically, marigold extract is extracted using multi-frequency ultrasound and compound enzyme extraction, which improves extraction efficiency and the purity of active ingredients; vine tea extract undergoes multi-step enzymatic hydrolysis and crystallization to remove impurities, and nano-emulsion encapsulation protects the integrity of flavonoids; the whey protein preparation process uses ultrasound and membrane treatment methods to avoid protein denaturation. These extraction processes ensure high concentrations and stability of active ingredients in feed additives, thereby maximizing bioavailability and achieving the goal of improving meat quality. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown herein can typically be arranged and designed in various different configurations.

[0016] Example 1 This embodiment discloses a plant extract feed additive for improving pork quality, which consists of the following components by weight: Stevia extract 10 parts, Eucommia ulmoides leaf extract 10 parts, Magnolia officinalis extract 5 parts, Marigold extract 5 parts, Astragalus membranaceus extract 10 parts, Taraxacum mongolicum extract 20 parts, Vine tea extract 20 parts, whey protein 2 parts.

[0017] The manufacturing method of this embodiment includes the following steps: S1. Raw Material Preparation Marigold extract, vine tea extract and whey protein were prepared separately, and stevia extract, eucommia leaf extract, magnolia bark extract, astragalus extract and dandelion extract were also prepared.

[0018] S2. Mixing Process Stevia extract, Eucommia leaf extract, Magnolia officinalis extract, Marigold extract, Astragalus membranaceus extract, Dandelion extract, and Vine tea extract are mixed with whey protein in a specific ratio and stirred thoroughly.

[0019] The preparation method of marigold extract in step S1 includes the following steps: S1-1-1. Pretreatment Marigold flowers are frozen, crushed, and then vacuum dried.

[0020] S1-1-2. Single extraction The pretreated material is mixed with an extraction solvent and subjected to ultrasound-assisted extraction in the presence of a complex enzyme; the complex enzyme is one or more of cellulase, β-glucanase and hemicellulase; the ultrasound-assisted extraction uses multi-frequency ultrasound, with a low frequency of 20kHz and a power of 300W, a medium frequency of 50kHz and a power of 230W, and a high frequency of 100kHz and a power of 180W.

[0021] S1-1-3. Secondary Extraction The filter residue after the first extraction was mixed with the extraction solvent again and subjected to variable amplitude ultrasonic extraction. S1-1-4. Post-processing The combined extracts were then subjected to microfiltration, nanofiltration concentration, and drying to obtain marigold extract. The frequency of the variable-amplitude ultrasound described in step S1-1-3 changes periodically between 30kHz and 50kHz, with a change period of 1 minute, and the ultrasound power is 380W.

[0022] This study employs multi-frequency ultrasound and compound enzyme extraction to extract marigold extract, which efficiently preserves lutein and carotenoids, effectively improving extraction efficiency and the purity of active ingredients. Simultaneously, the synergistic effect of variable amplitude ultrasound further disrupts cell wall structure, promoting the release of intracellular substances and significantly increasing the extraction rate.

[0023] In this embodiment, the preparation method of the vine tea extract in step S1 includes the following steps: S1-2-1. Freeze the stems and leaves of vine tea, then crush them and pass them through an 80-mesh sieve to obtain coarse vine tea powder; S1-2-2. The vine tea raw material undergoes a first extraction and a first enzymatic hydrolysis using a first enzyme. After the first enzymatic hydrolysis, a first enzyme inactivation treatment is performed to obtain a first extract, which is then concentrated to obtain a concentrated solution. The specific method is as follows: Add coarse vine tea powder to ethanol at a material-to-liquid ratio of 1:25 and extract once with ultrasound for 20 minutes. After extraction, filter and then add 2% (by weight of coarse vine tea powder) of cellulase and pectinase. After enzymatic hydrolysis, filter to obtain the first enzymatic hydrolysate. Then, incubate the first enzymatic hydrolysate at 45°C for 2 hours and then concentrate to obtain the concentrate. S1-2-3. The concentrate is subjected to a second enzymatic hydrolysis using a second enzyme. After the second enzymatic hydrolysis, a second enzyme inactivation treatment and a first crystallization treatment are performed to obtain the first crystals. The specific method is as follows: Add 3% by mass of a second enzyme to the concentrated solution obtained in step S1-2-2 for a second enzymatic hydrolysis. The second enzyme is at least one of cellulase, pectinase, and α-amylase. After the second enzymatic hydrolysis, filter to obtain a second enzymatic hydrolysis filtrate. Then, incubate the second enzymatic hydrolysis filtrate at 45°C for 1 hour. Then, perform a second enzyme inactivation treatment. After filtration, place the filtrate in a low-temperature environment at 2°C to crystallize. Filter the filtrate and take the filter residue. Then, dry it at 60°C to obtain the first crystal. S1-2-4. Add the first adsorbent to perform the second extraction and first decolorization treatment on the first crystal; The first crystal and activated carbon were added together with water and subjected to a second extraction under pressure and heating. The mass of activated carbon was 1% of the mass of the first crystal. The pressure of the second extraction was 0.2 MPa, the temperature was 90℃, and the extraction time was 2 hours. S1-2-5. Perform a second crystallization treatment to obtain a second crystal. The specific method is as follows: The extract obtained from S1-2-4 was placed in a low-temperature environment of 2℃ to crystallize, filtered, and the residue was collected. The residue was then repeatedly washed with ice water to clean the alcohol extraction reagent and activated carbon. The residue was then vacuum dried at 60℃ to obtain the second crystal. S1-2-6. Dissolve the second crystal in water to prepare an aqueous solution. Shear and mix the aqueous solution with an embedding aid and an emulsifier, homogenize three times, and then add the second adsorbent. The embedding aid includes sodium alginate, pectin, and gum arabic. The emulsifier is lecithin. The gum arabic contains 15% arabinogalactan protein and 3% glycoprotein. The second adsorbent is activated carbon. S1-2-7. The second adsorbent is separated from the filtrate and the filtrate is freeze-dried to obtain a water-soluble vine tea extract.

[0024] This embodiment employs enzymatic hydrolysis and nanoemulsion encapsulation technology to extract vine tea extract, which effectively improves the retention rate and bioavailability of flavonoids in the extract, while enhancing its antioxidant activity and stability. Synergistic treatment with compound enzymes effectively improves the dissolution efficiency of flavonoids, and the nanoemulsion encapsulation technology improves the dispersibility and intestinal absorption rate of water-soluble vine tea extract, ultimately yielding a high-purity, high-activity natural flavonoid product.

[0025] In this embodiment, the method for preparing whey protein in step S1 includes: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 80% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.3 W / cm³. 2 The interval is 30 minutes.

[0026] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.02MPa, and a flow rate of 5mL / min.

[0027] Example 2 This embodiment refers to the method provided in Example 1 for preparing plant extract feed additives. The difference between this embodiment and Example 1 is that the formula in this embodiment is different from that in Example 1. Apart from the above differences, the preparation method of the plant extract feed additive in this embodiment is strictly consistent with that in Example 1.

[0028] Specifically, this embodiment discloses a plant extract feed additive for improving pork quality, which consists of the following components in parts by weight: Stevia extract 30 parts, Eucommia ulmoides leaf extract 50 parts, Magnolia officinalis extract 15 parts, Marigold extract 20 parts, Astragalus membranaceus extract 30 parts, Taraxacum mongolicum extract 50 parts, Vine tea extract 50 parts, whey protein 5 parts.

[0029] Example 3 This embodiment refers to the method provided in Example 1 for preparing plant extract feed additives. The difference between this embodiment and Example 1 is that the formula in this embodiment is different from that in Example 1. Apart from the above differences, the preparation method of the plant extract feed additive in this embodiment is strictly consistent with that in Example 1.

[0030] Specifically, this embodiment discloses a plant extract feed additive for improving pork quality, which consists of the following components in parts by weight: Stevia extract 20 parts, Eucommia ulmoides leaf extract 30 parts, Magnolia officinalis extract 10 parts, Marigold extract 15 parts, Astragalus membranaceus extract 20 parts, Taraxacum mongolicum extract 35 parts, Chaenomeles speciosa extract 35 parts, whey protein 4 parts.

[0031] Example 4 This embodiment prepares plant extract feed additives with reference to the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that in S1-3-5, the inlet air temperature of the low-pressure spray drying process is 85°C and the outlet air temperature is 60°C. Apart from the above differences, the preparation method of plant extract feed additives in this embodiment is strictly consistent with that in Embodiment 1.

[0032] Specifically, in this embodiment, the method for preparing whey protein is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 80% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.3 W / cm³. 2 The interval is 30 minutes.

[0033] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 85°C, an outlet air temperature of 60°C, a vacuum degree of 0.02MPa, and a flow rate of 5mL / min.

[0034] Example 5 This embodiment prepares plant extract feed additives with reference to the formula and method provided in Example 1. The difference from Example 1 is that in S1-3-5, the vacuum degree of the low-pressure spray drying process is 0.4 MPa and the flow rate is 8 mL / min. Apart from the above differences, the preparation method of plant extract feed additives in this embodiment is strictly consistent with that in Example 1.

[0035] Specifically, in this embodiment, the method for preparing whey protein is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 80% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.3 W / cm³. 2 The interval is 30 minutes.

[0036] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.4MPa, and a flow rate of 8mL / min.

[0037] Example 6 This embodiment refers to the formula and method provided in Embodiment 1 to prepare plant extract feed additives. The difference from Embodiment 1 is that in S1-3-2, the ultrasonic treatment temperature is 30°C, the treatment time is 30 minutes, and the interval time is 40 minutes. Apart from the above differences, the preparation method of plant extract feed additives in this embodiment is strictly consistent with that in Embodiment 1.

[0038] Specifically, in this embodiment, the method for preparing whey protein is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 80% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 30°C, a treatment time of 30 minutes, and an ultrasonic power density of 0.3 W / cm³. 2 The interval is 40 minutes.

[0039] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.02MPa, and a flow rate of 5mL / min.

[0040] Example 7 This embodiment prepares a plant extract feed additive using the formula and method provided in Embodiment 1. The difference from Embodiment 1 is that in S1-3-2, the power density of the ultrasonic treatment is 0.6 W / cm³. 2 Apart from the differences mentioned above, the preparation method of the plant extract feed additive in this embodiment is strictly consistent with that in Example 1.

[0041] Specifically, in this embodiment, the method for preparing whey protein is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 80% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.6 W / cm³. 2 The interval is 30 minutes.

[0042] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.02MPa, and a flow rate of 5mL / min.

[0043] Example 8 This embodiment prepares plant extract feed additives according to the formula and method provided in Example 1. The difference from Example 1 is that in S1-1-2, the ultrasonic-assisted extraction uses multi-frequency ultrasound: low frequency 40kHz, power 320W; medium frequency 60kHz, power 250W; and high frequency 120kHz, power 200W; in S1-1-3, the amplitude-modulated ultrasound power is 420W. Apart from the above differences, the preparation method of the plant extract feed additives in this embodiment is strictly consistent with that in Example 1.

[0044] Specifically, in this embodiment, the preparation method of marigold extract includes the following steps: S1-1-1. Pretreatment Marigold flowers are frozen, crushed, and then vacuum dried.

[0045] S1-1-2. Single extraction The pretreated material is mixed with the extraction solvent and subjected to ultrasound-assisted extraction in the presence of a complex enzyme; the complex enzyme is one or more of cellulase, β-glucanase and hemicellulase; the ultrasound-assisted extraction uses multi-frequency ultrasound, with a low frequency of 40kHz and a power of 320W, a medium frequency of 60kHz and a power of 250W, and a high frequency of 120kHz and a power of 200W.

[0046] S1-1-3. Secondary Extraction The filter residue after the first extraction was mixed with the extraction solvent again and subjected to variable amplitude ultrasonic extraction. S1-1-4. Post-processing The combined extracts were then subjected to microfiltration, nanofiltration concentration, and drying to obtain marigold extract. The frequency of the variable-amplitude ultrasound described in step S1-1-3 changes periodically between 30kHz and 50kHz, with a change period of 1 minute, and the ultrasound power is 420W.

[0047] Example 9 This embodiment prepares a plant extract feed additive using the formula and method provided in Example 1. The difference from Example 1 is that the process parameters were adjusted when preparing the vine tea extract. Apart from the above differences, the preparation method of the plant extract feed additive in this embodiment is strictly consistent with that in Example 1.

[0048] Specifically, in this embodiment, the preparation method of vine tea extract includes the following steps: S1-2-1. Freeze the stems and leaves of vine tea, then crush them and pass them through an 80-mesh sieve to obtain coarse vine tea powder; S1-2-2. The vine tea raw material undergoes a first extraction and a first enzymatic hydrolysis using a first enzyme. After the first enzymatic hydrolysis, a first enzyme inactivation treatment is performed to obtain a first extract, which is then concentrated to obtain a concentrated solution. The specific method is as follows: Add coarse vine tea powder to ethanol at a material-to-liquid ratio of 1:35 and extract three times with ultrasound for 40 minutes each time. After extraction, filter the solution and then add 4% (by weight of coarse vine tea powder) of cellulase and pectinase. After enzymatic hydrolysis, filter the solution to obtain the first enzymatic hydrolysate. Then, incubate the first enzymatic hydrolysate at 60°C for 5 hours and then concentrate it to obtain the concentrated solution. S1-2-3. The concentrate is subjected to a second enzymatic hydrolysis using a second enzyme. After the second enzymatic hydrolysis, a second enzyme inactivation treatment and a first crystallization treatment are performed to obtain the first crystals. The specific method is as follows: Add 8% by mass of a second enzyme to the concentrated solution obtained in step S1-2-2 for a second enzymatic hydrolysis. The second enzyme is at least one of cellulase, pectinase, and α-amylase. After the second enzymatic hydrolysis, filter to obtain a second enzymatic hydrolysis filtrate. Then, incubate the second enzymatic hydrolysis filtrate at 60°C for 3 hours. Then, perform a second enzyme inactivation treatment. After filtration, place the filtrate in a low-temperature environment at 6°C to crystallize. Filter the filtrate and take the filter residue. Then, dry it at 60°C to obtain the first crystal. S1-2-4. Add the first adsorbent to perform the second extraction and first decolorization treatment on the first crystal; The first crystal and activated carbon were added together with water and subjected to a second extraction under pressure and heating. The mass of activated carbon was 15% of the mass of the first crystal. The pressure of the second extraction was 0.4 MPa, the temperature was 100℃, and the extraction time was 3 hours. S1-2-5. Perform a second crystallization treatment to obtain a second crystal. The specific method is as follows: The extract obtained from S1-2-4 was placed in a low-temperature environment of 6℃ to crystallize, filtered, and the residue was collected. The residue was then repeatedly washed with ice water to clean the alcohol extraction reagent and activated carbon. The residue was then vacuum dried at 60℃ to obtain the second crystal. S1-2-6. Dissolve the second crystal in water to prepare an aqueous solution. Shear and mix the aqueous solution with an embedding aid and an emulsifier, homogenize three times, and then add the second adsorbent. The embedding aid includes sodium alginate, pectin, and gum arabic. The emulsifier is lecithin. The gum arabic contains 25% arabinogalactan protein and 6% glycoprotein. The second adsorbent is activated carbon. S1-2-7. The second adsorbent is separated from the filtrate and the filtrate is freeze-dried to obtain a water-soluble vine tea extract.

[0049] Comparative Example 1 This comparative example prepares plant extract feed additives according to the formulation and method provided in Example 1. The difference between this comparative example and Example 1 is that in S1-3-2, the variable volume osmosis treatment method is to add deionized water at a rate of 78% osmosis flux. Apart from the above differences, the preparation method of plant extract feed additives in this example is strictly consistent with that in Example 1.

[0050] Specifically, the method for preparing whey protein in this comparative example is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 78% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.3 W / cm³. 2 The interval is 30 minutes.

[0051] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.02MPa, and a flow rate of 5mL / min.

[0052] Comparative Example 2 This comparative example prepares plant extract feed additives according to the formulation and method provided in Example 1. The difference between this comparative example and Example 1 is that in S1-3-2, the variable volume osmosis treatment method is to add deionized water at a rate of 82% osmosis flux. Apart from the above differences, the preparation method of plant extract feed additives in this example is strictly consistent with that in Example 1.

[0053] Specifically, the method for preparing whey protein in this comparative example is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 82% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.3 W / cm³. 2 The interval is 30 minutes.

[0054] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.02MPa, and a flow rate of 5mL / min.

[0055] Comparative Example 3 This comparative example prepares a plant extract feed additive using the formula and method provided in Example 1. The difference between this comparative example and Example 1 is that, in S1-3-2, the ultrasonic treatment power is 0.2 W / cm². 2 Apart from the differences mentioned above, the preparation method of the plant extract feed additive in this embodiment is strictly consistent with that in Example 1.

[0056] Specifically, the method for preparing whey protein in this comparative example is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 80% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.2 W / cm³. 2 The interval is 30 minutes.

[0057] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.02MPa, and a flow rate of 5mL / min.

[0058] Test Example 1 The purity and yield of the whey protein prepared in Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 were tested.

[0059] The testing method is as follows: by measuring the total nitrogen content of the sample and then multiplying it by the conversion factor of whey protein, the protein content, the purity of whey protein, and the yield of whey protein are calculated.

[0060] Table 1. Results of whey protein determination under different implementation schemes.

[0061] As shown in Table 1, different permeation flux parameters have a significant impact on the key indicators of whey protein products. Example 1 (80% permeation flux) showed the best performance in terms of protein content, whey protein purity, and yield, indicating that the 80% permeation flux condition can efficiently remove impurities while achieving efficient retention and recovery of the target whey protein, thus achieving the best balance between purity and yield.

[0062] In contrast, Comparative Example 1 (78% permeation flux) suffered from insufficient impurity removal due to inadequate water washing, resulting in lower purity and content. While Comparative Example 2 (82% permeation flux) had slightly higher purity and content than Comparative Example 1, it had the lowest yield, presumably due to excessively high flow rate leading to the loss of some target protein. Both results confirm that deviations from the optimal permeation flux parameter lead to a decline in overall product quality.

[0063] Comparative Example 3 uses an ultrasonic power density of 0.2 W / cm². 2 The processing method yielded whey protein purity and yield of 88.5% and 78.2%, respectively, which were significantly lower than those of Example 1. This indicates that under the same permeation flux conditions, a lower ultrasonic power density is insufficient to effectively break down whey protein aggregates, leading to increased mass transfer resistance, decreased retention efficiency, and consequently affecting the purity and yield of the final product.

[0064] The molecular weights of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were determined using SDS-PAGE, and the specific steps are as follows: 1. Accurately weigh each whey protein sample and prepare a 1 mg / mL solution with deionized water. Take an appropriate amount of protein solution and mix it with an equal volume of 2×SDS-PAGE loading buffer (containing SDS and β-mercaptoethanol). Heat in a boiling water bath for denaturation for 5 minutes, then cool and set aside. 2. Using a 4%-20% pre-prepared gradient polyacrylamide gel, add pre-stained protein molecular weight standards (Protein Ladder) and denatured protein samples from Examples 1 and Comparative Examples 1-3 sequentially to the sample wells. In 1×Tris-glycine-SDS electrophoresis buffer, the initial voltage is 80V. After the sample enters the separating gel, the voltage is increased to 120V until the bromophenol blue indicator reaches the bottom of the gel. 3. After electrophoresis, remove the gel and stain it with Coomassie Brilliant Blue R-250 for 1 hour. Then, destain with destaining solution (acetic acid:methanol:water = 1:4:5) until the background is transparent and the protein bands are clear; 4. Use a gel imaging system to scan the gel images, and use image analysis software to fit the migration distance of each protein band to the standard curve of the protein molecular weight standard, and calculate the apparent molecular weight of the main protein components in the sample.

[0065] Table 2. Results of molecular weight determination of major components of whey protein

[0066] The results showed that the molecular weight distribution of the whey protein obtained in Example 1 was in high agreement with the theoretical values ​​of standard α-lactalbumin (~14.2 kDa) and β-lactoglobulin (~18.4 kDa), and the electrophoretic bands were clear and uniform, without obvious degradation bands or high molecular weight aggregates. This indicates that the molecular weight distribution was well-matched at 80% permeability flux and 0.3 W / cm². 2 Under the synergistic effect of ultrasonic power, the natural structure of whey protein was best preserved, without significant hydrolysis or excessive aggregation.

[0067] The molecular weight of the main protein component in Comparative Example 1 did not change significantly, which corresponds to the results of lower purity and yield in Test Example 1. This indicates that the problem with Comparative Example 1 is mainly due to low impurity removal efficiency, rather than structural damage to the target protein.

[0068] Comparative Example 2 showed a weak degradation band below the β-lactoglobulin site, indicating that excessive osmotic flux may have caused slight shear damage to the protein, leading to the hydrolysis or breakage of some β-lactoglobulin, and some target proteins could not be effectively recovered due to structural damage.

[0069] Comparative Example 3 electrophoresis results showed the presence of high molecular weight aggregates at the top of the gel. This indicates that when the ultrasonic power density is reduced to 0.2 W / cm², the situation changes. 2At that time, the cavitation effect and mechanical disturbance were insufficient to effectively prevent protein deposition and aggregation on the membrane surface. This resulted in aggregates with excessively large molecular weights, which were retained and lost during subsequent microfiltration and percolation processes, directly leading to the lowest yield (78.2%) and lower purity (88.5%) in Comparative Example 3.

[0070] The whey protein prepared in Example 1 and Comparative Examples 1-3 was further processed into feed additives and fed to weaned piglets at a dosage of 1%. Growth performance and health status were observed after 28 days of continuous feeding. The results showed that the daily weight gain of piglets in Example 1 group was significantly higher than that of the comparative groups (p<0.05), and the diarrhea rate was the lowest (4.3%). This indicates that the whey protein in Example 1 has a complete structure, is easily digested and absorbed, effectively promotes intestinal health and immune function, and promotes pig growth.

[0071] Comparative Example 4 This comparative example prepares plant extract feed additives according to the formulation and method provided in Example 1. The difference from Example 1 is that in S1-3-5, the inlet air temperature of the low-pressure spray drying process is 60°C, the outlet air temperature is 45°C, the vacuum degree is 0.02 MPa, and the flow rate is 3 mL / min. Apart from the above differences, the preparation method of the plant extract feed additives in this example is strictly consistent with that in Example 1.

[0072] Specifically, the method for preparing whey protein in this comparative example is as follows: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. The variable volume osmosis treatment method involves adding deionized water at a rate of 78% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20°C, a treatment time of 20 minutes, and an ultrasonic power density of 0.3 W / cm³. 2 The interval is 30 minutes.

[0073] S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The low-pressure spray drying process has an inlet air temperature of 60°C, an outlet air temperature of 45°C, a vacuum degree of 0.02MPa, and a flow rate of 3mL / min.

[0074] The whey protein prepared in Comparative Example 4 was compared with that prepared in Example 1, and the results are as follows.

[0075] Table 3 Comparison of product performance under different spray drying flow rates

[0076] Example 1, using a higher flow rate of 5 mL / min, achieved a yield (88.3%) significantly higher than that of Comparative Example 4, which used a flow rate of 3 mL / min (82.5%). This is mainly because the higher flow rate increased the material throughput per unit time, optimized the equipment's production capacity, and reduced static residue and wall adhesion losses within the equipment.

[0077] The prepared whey protein samples had essentially the same properties. The main difference lay in the moisture content. Comparative Example 4, due to its slower flow rate and more thorough drying, had a slightly lower moisture content, but the difference in moisture content was minimal, and there was no significant difference in their physical properties.

[0078] Comparative Example 5 This comparative example prepares a plant extract feed additive using the formula and method provided in Example 1. The difference from Example 1 is that in step S1-1-3, this comparative example uses a constant frequency of 40 kHz for ultrasonic treatment, with a treatment time of 1 minute and an ultrasonic power of 380 W. Apart from the above differences, the preparation method of the plant extract feed additive in this example is strictly consistent with that in Example 1.

[0079] Specifically, the preparation method of marigold extract in this comparative example includes the following steps: S1-1-1. Pretreatment Marigold flowers are frozen, crushed, and then vacuum dried.

[0080] S1-1-2. Single extraction The pretreated material is mixed with an extraction solvent and subjected to ultrasound-assisted extraction in the presence of a complex enzyme; the complex enzyme is one or more of cellulase, β-glucanase and hemicellulase; the ultrasound-assisted extraction uses multi-frequency ultrasound, with a low frequency of 20kHz and a power of 300W, a medium frequency of 50kHz and a power of 230W, and a high frequency of 100kHz and a power of 180W.

[0081] S1-1-3. Secondary Extraction The filter residue after the first extraction was mixed with the extraction solvent again and subjected to variable amplitude ultrasonic extraction. S1-1-4. Post-processing The combined extracts were then subjected to microfiltration, nanofiltration concentration, and drying to obtain marigold extract. The ultrasonic frequency described in step S1-1-3 is 40kHz, and the ultrasonic power is 380W.

[0082] In both Example 1 and Comparative Example 3, ultrasound was performed for 10 minutes at room temperature during steps S1-1-3. After ultrasounding, the temperature of the extract in Example 1 was 45.3 ± 1.2 °C, while the temperature of the extract in Comparative Example 3 was 53.6 ± 0.9 °C. This indicates that variable amplitude ultrasound can reduce heat accumulation during ultrasounding, preventing the heat-sensitive active ingredients in marigold from being destroyed by heat. Furthermore, the extraction rate of marigold active ingredients in Example 1 was 12.7% higher than that in the comparative example, indicating that variable amplitude ultrasound has a better extraction effect.

[0083] Comparative Example 6 In this comparative example, the extract of vine tea was extracted using the ethanol reflux method, as follows: 1. Drying and Grinding: Further clean the dried vine tea leaves to remove impurities; then grind them using a grinder; 2. Sieving: The powder is sieved through an 80-mesh sieve to obtain vine tea powder with uniform particle size; 3. Feeding: Put the vine tea powder into a round-bottom flask, and add 75% ethanol solution at a ratio of 1:25; 4. Heating and reflux: Turn on the water bath or electric heating mantle and heat the round-bottom flask at 70°C. When the ethanol begins to boil, adjust the temperature to keep the solution at a gentle boil. The vapor will condense in the condenser and reflux back into the flask. After refluxing for 2 hours, stop heating, cool, filter, and extract the filtrate. Put the filter residue back into the round-bottom flask and repeat the reflux twice.

[0084] 5. Post-processing and concentration: Combine all the extracts to obtain the total ethanol extract of vine tea, and concentrate it under reduced pressure using a rotary evaporator at 50°C.

[0085] 6. Drying: After concentration, place in a vacuum drying oven and dry at 60°C under negative pressure until constant weight to obtain vine tea extract.

[0086] In Example 1, the method for preparing vine tea extract yielded 25.7% flavonoids and 91.2% dihydromyricetin. In Comparative Example 6, the method for preparing vine tea extract yielded 18.6% flavonoids and 43.8% dihydromyricetin. The traditional ethanol reflux method, while extracting flavonoids, also extracts large amounts of impurities such as cellulose, starch, protein, and pigments, resulting in a considerable yield but very low purity.

[0087] Example 1 employs a multi-step enzymatic hydrolysis-crystallization-nanoemulsification integrated process. This process efficiently hydrolyzes cell walls using cellulase and pectinase, increasing the release and yield of flavonoids. Simultaneously, it utilizes the change in solubility of dihydromyricetin in a specific solvent system, causing it to precipitate in crystalline form, while most impurities remain in the mother liquor, thereby improving the purity of the extract. Furthermore, the nanoemulsification integrated process in Example 1 encapsulates high-purity flavonoids within a nanoscale carrier, effectively isolating them from the external environment and ensuring the stability and integrity of the active ingredients.

[0088] Test Example 2 To scientifically verify the effect of the plant extract feed additive in this scheme on improving pork quality, this invention sets up a control experiment. By comparing with the blank group and the traditional chemical additive group, the feed additive of this invention is verified in terms of growth performance and pork quality.

[0089] 1. Experimental subjects: 120 three-way crossbred commercial pigs with similar health status, age of 60 days, and initial weight of 25±2kg were selected and randomly divided into 3 groups, with 4 replicates in each group and 10 pigs (half male and half female) in each replicate to eliminate the interference of individual differences on the experimental results.

[0090] 2. Trial period: Covering the entire fattening stage, a total of 90 days, from 60 days to 150 days of age, corresponding to the common cycle of pork entering the market.

[0091] 3. Feeding environment: All three groups of pigs were kept in the same pigsty, with the same temperature, humidity, light and ventilation conditions; the same pen size (10㎡ per pen) was used, and they had free access to feed and water. The amount of feed consumed was recorded daily, and the pens were cleaned regularly to ensure that the feeding and management conditions were completely consistent.

[0092] 4. Grouping, including: Blank control group: basal diet (60% corn, 22% soybean meal, 10% wheat bran, 3% fish meal, 1.5% limestone, 2% dicalcium phosphate, 0.3% salt, 1.2% premix), without any additives to improve pork quality.

[0093] Traditional chemical additive group: Add a combination of mainstream chemical additives (0.02% ethoxyquinoline, 0.01% vitamin E, 0.03% tea polyphenols) to the basal diet.

[0094] Experimental group: The plant extract feed additive prepared in Example 1 was added to the basal diet at a dosage of 1%.

[0095] 5. Test and detection indicators and methods (1) Growth performance indicators: Initial and final weight: On day 1 and day 90 of the experiment, each head was weighed after fasting for 12 hours. The average initial weight, average final weight and average daily weight gain for each group were calculated (ADG = (final weight - initial weight) / number of days of the experiment).

[0096] Average Daily Feed Intake (ADFI): The total feed intake of each group is recorded daily and summarized weekly to calculate the average daily feed intake over the entire period.

[0097] Feed conversion ratio (FCR): The feed conversion ratio is calculated based on ADFI and ADG (FCR=ADFI / ADG). The lower the feed conversion ratio, the higher the feed conversion efficiency.

[0098] (2) Pork quality indicators Meat color: 45 min and 24 h after slaughter, the L value (brightness), a value (redness), and b value (yellowness) of the central part of the eye muscle were measured using a colorimeter.

[0099] pH value: 45 min (pH1) and 24 h (pH24) after slaughter, the pH meter was inserted into the center of the eye muscle, and each sample was measured 3 times and the average value was taken.

[0100] Tenderness: 24 hours after slaughter, take meat samples (2cm×2cm×5cm) from the middle of the eye muscle and measure the shear force using a texture analyzer (cross-cross method, shearing speed 2mm / s).

[0101] Marbling: 24 hours post-slaughter, a cross-section of the eye muscle was taken, and the marbling of the meat sample was scored. The average score was calculated through blind scoring by three professional scorers. The scoring criteria are as follows: 1 point: There is almost no visible fat deposit on the surface of the muscle, the overall color is dark red, and the texture is lean and dry.

[0102] 2 points: There are very few scattered fat spots. The fat particles are relatively large and isolated, unevenly distributed, mainly concentrated at the edge of the muscle or in individual areas, while the muscle as a whole remains predominantly red.

[0103] 3 points: The number of fat spots is moderate and they are relatively evenly distributed, with some fine fat striations beginning to appear. The muscles are a mix of red and white, and the proportions are harmonious.

[0104] 4 points: Abundant fat deposits, with fine fat striations covering the entire muscle cross-section, forming a clear network structure. White fat blends harmoniously with red muscle in a balanced proportion.

[0105] 5 points: Extremely rich fat deposits, forming a dense, fine, and uniform net-like or snowflake-like texture. The muscle cross-section presents a beautiful "marble" or "frost" appearance.

[0106] Table 4 Results of growth performance indicators

[0107] The experimental group had significantly higher final body weight and ADG than the other two groups (P<0.05); and significantly lower FCR than the other two groups (P<0.05), indicating the best feed conversion ratio.

[0108] Table 5 Results of Pork Quality Indicators

[0109] All indicators of the experimental group were significantly better than those of the other two groups (P<0.05): the meat color was brighter, the pH was more stable, the tenderness was higher, the marbling was more moderate, and the water retention was stronger.

[0110] As can be seen from the two tables above, the plant extract feed additives in this scheme can comprehensively outperform other groups in improving growth performance and meat quality, especially in terms of meat color redness and water retention, indicating that they have good antioxidant capacity and intramuscular fat regulation effect; at the same time, they significantly increase daily weight gain and reduce feed conversion ratio, indicating that they can effectively promote the absorption and utilization of nutrients.

[0111] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A plant extract feed additive for improving pork quality, characterized in that, It consists of the following components in parts by weight: Stevia extract 10-30 parts, Eucommia ulmoides leaf extract 10-50 parts, Magnolia officinalis extract 5-15 parts, Marigold extract 5-20 parts, Astragalus membranaceus extract 10-30 parts, Taraxacum mongolicum extract 20-50 parts, Chaenomeles speciosa extract 20-50 parts, whey protein 2-5 parts.

2. A method for preparing a plant extract feed additive for improving pork quality according to claim 1, characterized in that, Includes the following steps: S1. Raw Material Preparation Marigold extract, vine tea extract and whey protein were prepared separately, and stevia extract, eucommia leaf extract, magnolia bark extract, astragalus extract and dandelion extract were also prepared. S2. Mixing Process Stevia extract, Eucommia ulmoides leaf extract, Magnolia officinalis extract, Marigold extract, Astragalus membranaceus extract, Dandelion extract, and vine tea extract are mixed with whey protein in a certain proportion and stirred thoroughly to obtain a feed additive.

3. The preparation method according to claim 2, characterized in that, The preparation method of marigold extract in step S1 includes the following steps: S1-1-1. Pretreatment Marigold flowers were frozen, pulverized, and then vacuum dried. S1-1-2. Single extraction The pretreated material was mixed with the extraction solvent and then subjected to ultrasound-assisted extraction in the presence of a complex enzyme. S1-1-3. Secondary Extraction The filter residue after the first extraction was mixed with the extraction solvent again and subjected to variable amplitude ultrasonic extraction. S1-1-4. Post-processing The combined extracts were then subjected to microfiltration, nanofiltration concentration, and drying to obtain marigold extract. The complex enzyme mentioned in step S1-1-2 is one or more of cellulase, β-glucanase and hemicellulase; The ultrasound-assisted extraction described in step S1-1-2 uses multi-frequency ultrasound, with a low frequency of 20-40kHz and a power of 300-320W, a medium frequency of 50-60kHz and a power of 230-250W, and a high frequency of 100-120kHz and a power of 180-200W. The frequency of the variable-amplitude ultrasound described in step S1-1-3 varies periodically between 30kHz and 50kHz, with a variation period of 1-3 minutes, and the ultrasound power is 380-420W.

4. The preparation method according to claim 2, characterized in that, The preparation method of the vine tea extract in step S1 includes the following steps: S1-2-1. Freeze the stems and leaves of vine tea, then crush them and pass them through an 80-100 mesh sieve to obtain coarse vine tea powder; S1-2-2. The vine tea raw material is subjected to a first extraction and a first enzymatic hydrolysis with a first enzyme. After the first enzymatic hydrolysis, a first enzyme inactivation treatment is performed to obtain a first extract, and the first extract is concentrated to obtain a concentrated liquid. S1-2-3. The concentrate is subjected to a second enzymatic hydrolysis with a second enzyme, followed by a second enzyme inactivation treatment and a first crystallization treatment to obtain the first crystal; S1-2-4. Add the first adsorbent to perform the second extraction and first decolorization treatment on the first crystal; S1-2-5. Perform a second crystallization process to obtain a second crystal; S1-2-6. Dissolve the second crystal in water to prepare an aqueous solution, and then mix the aqueous solution with the embedding aid and emulsifier by shearing, homogenize three times, and then add the second adsorbent. S1-2-7. The second adsorbent is separated from the filtrate and the filtrate is freeze-dried to obtain a water-soluble vine tea extract; The first extraction is ultrasonic ethanol extraction, the second extraction is heating and pressurizing water extraction, the first enzyme is cellulase and pectinase; the second enzyme is at least one of cellulase, pectinase and α-amylase.

5. The preparation method according to claim 4, characterized in that, The first extraction method is as follows: add coarse vine tea powder to ethanol, with a material-to-liquid ratio of 1:25-35, and extract by ultrasound 1-3 times, each time for 20-40 minutes; The second extraction method is as follows: the first crystal is added to water and extracted for 2-3 hours under the conditions of pressure of 0.2-0.4 MPa and temperature of 90-100℃.

6. The preparation method according to claim 4, characterized in that, The amount of the first enzyme added is 2-4% of the mass of the coarse vine tea powder. After the first enzymatic hydrolysis, the mixture is filtered to obtain the first enzymatic hydrolysis filtrate. The first enzymatic hydrolysis filtrate is then incubated at 45-60℃ for 2-5 hours. The amount of the second enzymatic hydrolysate added is 3-8% of the concentrate. After the second enzymatic hydrolysate, the solution is filtered to obtain the second enzymatic hydrolysate. The second enzymatic hydrolysate is then incubated at 45-60℃ for 1-3 hours.

7. The preparation method according to claim 4, characterized in that, The first crystallization treatment method is as follows: the second enzyme hydrolysis filtrate after the second enzyme inactivation treatment is placed in a low temperature environment of 2-6℃ to crystallize, filtered to obtain the filter residue, and then dried at 60℃. The second crystallization treatment method is as follows: place the raw material in a low temperature environment of 2-6℃ to crystallize, filter and take the filter residue, and then wash it repeatedly with ice water to clean the alcohol extraction reagent and the first adsorbent. The first adsorbent and the second adsorbent are activated carbon. The amount of the first adsorbent is 1%-15% of the mass of the first crystal. The first decolorization treatment time is 10-40 min. After decolorization, the first decolorized liquid is separated from the first adsorbent.

8. The preparation method according to claim 4, characterized in that, The encapsulation aid includes one or more of sodium alginate, pectin, and gum arabic, and the emulsifier is lecithin; the gum arabic contains 15-25% arabinogalactan protein and 3-6% glycoprotein.

9. The preparation method according to claim 2, characterized in that, The method for preparing whey protein in step S1 includes: S1-3-1. The milk raw material is defatted to obtain skimmed milk, which is then pasteurized and heated to 50°C. Subsequently, it is microfiltered using a 0.1μm ceramic membrane to obtain the first permeate and the first retentate. S1-3-2. The first permeate is subjected to percolation treatment to remove whey protein and retain casein. In the percolation treatment, variable volume percolation treatment and ultrasonic treatment are used simultaneously to obtain a second permeate and a second retained liquid. S1-3-3: Divide the second permeate into pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D; divide the second retentate into pretreated retentate a, pretreated retentate b, and pretreated retentate c. S1-3-4. Subsequently, a multi-component purification process is performed, wherein the purification process is microfiltration; S1-3-5: The purified pretreated permeate A, pretreated permeate B, pretreated permeate C, and pretreated permeate D are sequentially subjected to low-pressure spray drying to obtain whey protein. The inlet air temperature of the low-pressure spray drying process is 60-85℃, the outlet air temperature is 45-60℃, the vacuum degree is 0.02-0.4MPa, and the flow rate is 5-8mL / min.

10. The preparation method according to claim 9, characterized in that, The variable volume osmosis treatment method described in step S1-3-2 involves adding deionized water at a rate of 80% osmosis flux. The ultrasonic treatment is intermittent, with a treatment temperature of 20-30℃, a treatment time of 20-30 minutes, and an ultrasonic power density ≥0.3W / cm³. 2 The interval is 30-40 minutes.

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