Natural plant extract compound feed additive for improving quality of snowflake pork

Abstract

The present application relates to the technical field of feed, in particular to a kind of natural plant extract composite feed additive for improving quality of snowflake pork.The core is that epigallocatechin gallate hydrate is partially palmitoylated to improve fat solubility, and pre-structured oil phase is formed with phospholipid and stepwise added soybean oil.The oil phase forms initial milk with emulsified soybean protein isolate aqueous phase, and then pre-wet state and hydrated state tea saponin are added in sequence, and powder is obtained by homogenization and spray drying.The method constructs stable and interfacially ordered delivery system, which can synergistically improve intramuscular fat content, marbling score of fattening pigs, and effectively reduce drip loss.

Description

Technical Field

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

[0002] Snowflake pork, with its rich marbling (intramuscular fat) and excellent water retention (low drip loss), possesses higher commercial value and superior flavor. In the later stages of pig fattening, how to stably increase intramuscular fat content and reduce drip loss through nutritional regulation is an important research direction in pig farming and meat quality improvement. Natural plant extracts, such as tea polyphenols, are considered potential additives for improving pork quality due to their potential functions in regulating lipid metabolism and antioxidation.

[0003] However, tea polyphenols are highly water-soluble but poorly lipid-soluble, making it difficult for them to effectively integrate into the lipid phase and bind to key sites of intramuscular fat deposition during conventional feed processing and in the animal digestive tract environment. This results in low bioavailability and limited, unstable improvement effects. To address the lipid solubility issue, existing technologies attempt to chemically modify tea polyphenols, such as through methylation or complete fatty acid esterification. However, while complete hydrophobic modification increases lipid solubility, it may excessively shield their active phenolic hydroxyl groups, weakening their function in interfacial interactions and subsequent biological regulation.

[0004] Furthermore, to improve the dispersion and delivery efficiency of modified active ingredients, existing technologies often employ microencapsulation or self-emulsification formulations. These methods typically focus on encapsulating the active ingredient for protection or sustained release, but they generally suffer from problems such as a simple interfacial structure and inaccurate localization of the active ingredient at the oil-water interface. This leads to the carrier easily agglomerating, delaminating, or prematurely rupturing during reconstitution, processing, storage, and in vivo digestion. The active ingredient cannot be delivered to the site of action in an orderly and efficient manner, limiting its synergistic effect on improving intramuscular fat deposition and muscle water retention.

[0005] Furthermore, in constructing emulsion delivery systems, a single emulsifier (such as soy protein isolate or tea saponin) is often used to stabilize the system through simple mixing. This method results in insufficient interfacial structural strength, poor adaptability to varying environmental stresses (such as temperature, ionic strength, and digestive environment), and large batch-to-batch stability fluctuations. Unstable delivery systems can cause active ingredients to degrade or leak before storage and feeding, failing to guarantee that they are ingested by animals in the designed form and dosage to exert their effects. Ultimately, this leads to poor reproducibility of application effects, making it difficult to consistently achieve the dual optimization goals of marbled pork quality in actual production. Summary of the Invention

[0006] In view of this, the purpose of this invention is to propose a natural plant extract compound feed additive to improve the quality of Wagyu pork, in order to solve the problems of poor fat solubility, disordered interface distribution, low delivery efficiency and system instability of existing additives for improving the quality of Wagyu pork, which makes it difficult to synergistically improve intramuscular fat deposition and water retention.

[0007] To achieve the above objectives, this invention provides a natural plant extract compound feed additive for improving the quality of marbled pork, which is prepared from the following raw materials by mass: 130-170 parts of tea polyphenols partially palmitated ester product, 50-70 parts of L-α-phosphatidylcholine, 200-280 parts of non-GMO soybean oil, 70-90 parts of emulsified soy protein isolate, 30-47 parts of tea saponin and 550-750 parts of maltodextrin. The partially palmitated product is obtained by partial esterification of epigallocatechin gallate hydrate and vinyl palmitate under the catalysis of immobilized lipase; the non-GMO soybean oil includes a first portion of non-GMO soybean oil and a second portion of non-GMO soybean oil, wherein the first portion of non-GMO soybean oil, together with the partially palmitated product and L-α-phosphatidylcholine, forms an oil phase, and the second portion of non-GMO soybean oil is added to the oil phase during the ethanol removal process; the tea saponin includes pre-wetted tea saponin and hydrated tea saponin, wherein the pre-wetted tea saponin is first added to the colostrum formed by the oil phase and the aqueous phase of emulsified soy protein isolate, and the hydrated tea saponin is added later; the compound feed additive is a powder obtained by homogenization and spray drying.

[0008] Preferably, the first portion of non-GMO soybean oil is 60-100 parts, the second portion of non-GMO soybean oil is 140-180 parts, and 240-360 parts of anhydrous ethanol are added during the formation of the oil phase.

[0009] Preferably, the partially palmitated product is prepared by the following method: 100-140 parts of epigallocatechin gallate hydrate, 150-220 parts of vinyl palmitate, 1600-2000 parts of anhydrous tert-butanol, 80-120 parts of 4A molecular sieve and 50-70 parts of immobilized lipase are mixed and reacted at 45-55℃ and 180-250rpm for 12-20h; after the reaction, the product is obtained by hot filtration, removal of tert-butanol under reduced pressure, washing with n-hexane and vacuum drying at 30-40℃.

[0010] Preferably, the esterification conversion rate of the partially palmitated ester product is 45.1%-70.6%.

[0011] Preferably, the total mass of the pre-wetted tea saponin and the hydrated tea saponin is 30-47 parts, and the mass ratio of the two is 1.5:1-3:1.

[0012] Preferably, the pre-wetted tea saponin is obtained by mixing 20-35 parts of tea saponin with 90-140 parts of 70% ethanol, and the hydrated tea saponin is obtained by mixing 10-18 parts of tea saponin with 120-180 parts of purified water.

[0013] Preferably, the immobilized lipase is derived from Candida antarctica and has a specific activity greater than 2 U / mg.

[0014] Preferably, the emulsified soy protein isolate aqueous phase is formed by hydrating 70-90 parts of emulsified soy protein isolate with 1800-2000 parts of purified water.

[0015] Furthermore, the present invention also provides a method for preparing a compound feed additive of natural plant extracts, comprising the following steps: (1) Preparation of partially palmitated tea polyphenol esters; (2) The palmitate esterification product, L-α-phosphatidylcholine (soybean), the first part of non-GMO soybean oil and anhydrous ethanol are mixed, and the second part of non-GMO soybean oil is added during the process of removing ethanol under reduced pressure to obtain the oil phase; (3) Mix emulsified soy protein isolate with purified water and hydrate to obtain an aqueous phase; add the oil phase to the aqueous phase for shear emulsification to obtain a promulgated emulsion; (4) Add pre-wetted tea saponin to the colostrum first, then add hydrated tea saponin to obtain a composite emulsion; (5) Add maltodextrin to the composite emulsion, homogenize and spray dry to obtain a natural plant extract composite feed additive.

[0016] Preferably, in step (3), the shearing emulsification is performed by shearing at 10,000-14,000 rpm for 3-5 minutes.

[0017] Preferably, in step (5), homogenization is performed once at 15-25 MPa.

[0018] Preferably, in step (5), the spray drying is performed with an inlet air temperature of 145-155°C and an outlet air temperature of 75-82°C.

[0019] The beneficial effects of this invention are: This invention partially palmitates epigallocatechin gallate, improving its lipid affinity while retaining essential free phenolic hydroxyl groups. This modified product, through a process of pre-association followed by oil replenishment with L-α-phosphatidylcholine in the soybean oil phase, pre-forms a stable interfacial anchoring structure in the emulsion system before spray drying. This structure ensures that the core active substance preferentially and stably distributes at the emulsion droplet interface after resolidification, rather than simply dissolving within the oil core, thereby significantly improving the uniformity and interfacial electrochemical stability of the dispersion system, which is beneficial for maintaining integrity during subsequent processing, storage, and in the intestinal environment.

[0020] This invention achieves hierarchical and functional construction of emulsifiers at the interface by preparing tea saponins into pre-wetted concentrates and hydrated solutions, which are then sequentially added to the colostrum system. The pre-wetted tea saponins can more effectively insert into and stabilize the initially formed oil-water interface film, while the subsequently added hydrated tea saponins can form a stable hydration shell on the outer layer of the interface. This synergistic effect significantly enhances the tolerance of the entire emulsion delivery system to mechanical shear, thermal stress, and storage oxidation, ensuring the retention rate and functional state of the active components before feeding.

[0021] The synergy of the aforementioned molecular level (partial esterification), interfacial level (phospholipid association and stepwise construction), and process timing constitutes a highly efficient and stable targeted delivery system. This system can promote the absorption and transport of active substances in animals, and more precisely act on the relevant pathways of lipid metabolism and muscle water retention. Thus, in the later stages of fattening of Snowflake pigs, it can simultaneously and stably achieve the dual quality improvement goals of increasing intramuscular fat content, improving marbling score, and reducing drip loss, overcoming the shortcomings of limited and unstable effects of single components or simple compound formulations. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0023] The raw materials used were sourced as follows: Epigallocatechin gallate hydrate, TCI (Shanghai) Chemical Industry Development Co., Ltd., item number E0694, purity greater than 98.0%; L-α-phosphatidylcholine (soybean), Shanghai Aladdin Biochemical Technology Co., Ltd., item number L130333, natural, purity not less than 99%; tea saponin, Shanghai Aladdin Biochemical Technology Co., Ltd., item number S639548; immobilized lipase derived from Candida antarctica, Sigma-Aldrich, item number 73940, granular, specific activity greater than 2U / mg; emulsified soy protein isolate, Shandong Yuwang Ecological Food Industry Co., Ltd., emulsified type; non-GMO soybean oil, Shandong Yuwang Ecological Food Industry Co., Ltd.; maltodextrin, Baolingbao Biotechnology Co., Ltd., model MD10. Vinyl palmitate, anhydrous tert-butanol, anhydrous ethanol, n-hexane, and 4A molecular sieve were all commercially available analytical grade or chemically pure products.

[0024] Example 1:

[0025] Step 1: 120g of epigallocatechin gallate hydrate, 180g of vinyl palmitate, 1800g of anhydrous tert-butanol, 100g of 4A molecular sieve, and 60g of immobilized lipase were sequentially added to a reaction flask equipped with a stirrer and reflux device. After purging with nitrogen for 5 minutes, the mixture was reacted at 50℃ and 200rpm for 16 hours. After the reaction was completed, the mixture was filtered while hot. The filter cake was washed once with 100g of anhydrous tert-butanol and the washed cake was added to the filtrate. The tert-butanol was then removed under reduced pressure below 45℃. 300g of n-hexane pre-cooled to 5℃ was added to the resulting concentrate in two portions, 150g each time. After washing, the washings were discarded to remove unreacted vinyl palmitate. The residue was then dried under vacuum at 35℃ for 12 hours to obtain the partially palmitated polyphenol product. Step 2: Take 150g of the palmitate esterified product of tea polyphenols obtained in Step 1, 60g of L-α-phosphatidylcholine, 80g of non-GMO soybean oil and 300g of anhydrous ethanol and add them to a jacketed stirring container. Stir at 50℃ and 600rpm for 40min. Then, keep at 50℃ and under reduced pressure, remove ethanol while adding 160g of non-GMO soybean oil over 20min. Continue stirring for 20min to obtain the oil phase concentrate. Step 3: Add 80g of emulsified soy protein isolate and 1920g of purified water to a mixing tank, stir at 25℃ and 500rpm for 30min, and then let stand for 60min to complete hydration to obtain the protein aqueous phase; then add the oil phase concentrate obtained in step 2 to the protein aqueous phase, and perform high shear at 12000rpm for 4min to obtain the colostrum. Step 4: Mix 30g of tea saponin with 120g of 70% ethanol and stir at 45℃ and 400rpm for 20min to obtain a pre-wetted tea saponin concentrate; separately, mix 15g of tea saponin with 150g of purified water and hydrate at 25℃ and 400rpm for 40min to obtain a hydrated tea saponin solution. First, add the pre-wetted tea saponin concentrate to the colostrum obtained in Step 3, shear at 45℃ and 8000rpm for 2min, then keep warm at 500rpm for 10min; then lower the system temperature to 28℃, add the hydrated tea saponin solution within 15min, and continue stirring at 500rpm for 20min to obtain a composite emulsion; Step 5: Add 650g of maltodextrin to the composite emulsion obtained in Step 4, stir at 25℃ and 500rpm for 20min, then homogenize once at 20MPa, and then spray dry to make powder, controlling the inlet air temperature to 150℃ and the outlet air temperature to 78℃, to obtain a natural plant extract composite feed additive that improves the quality of snowflake pork. Step 6: Mix the natural plant extract compound feed additive obtained in Step 5 at a ratio of 1.5 kg per 1000 kg of corn and soybean meal-based fattening basal complete feed, and feed it to fattening pigs weighing 75-115 kg for 42 consecutive days.

[0026] Example 2:

[0027] Step 1: 100g epigallocatechin gallate hydrate, 150g vinyl palmitate, 1600g anhydrous tert-butanol, 80g 4A molecular sieve, and 50g immobilized lipase were sequentially added to a reaction flask equipped with a stirrer and reflux device. Nitrogen gas was introduced for 4 minutes, and the mixture was reacted at 45℃ and 180rpm for 12 hours. After the reaction was completed, the mixture was filtered while hot. The filter cake was washed once with 80g anhydrous tert-butanol and the washed cake was added to the filtrate. The tert-butanol was then removed under reduced pressure below 40℃. 240g of n-hexane pre-cooled to 8℃ was added to the concentrate in two portions, 120g each time. The washings were discarded to remove unreacted vinyl palmitate. The residue was then dried under vacuum at 30℃ for 10 hours to obtain the partially palmitated polyphenol product. Step 2: Take 130g of the palmitate esterified product of tea polyphenols obtained in Step 1, 50g of L-α-phosphatidylcholine (soybean), 60g of non-GMO soybean oil and 240g of anhydrous ethanol and add them to a jacketed stirring container. Stir at 45℃ and 500rpm for 30min. Then, while maintaining 45℃, add 140g of non-GMO soybean oil under reduced pressure while removing ethanol within 15min. Continue stirring for 15min to obtain the oil phase concentrate. Step 3: Add 70g of emulsified soy protein isolate and 1800g of purified water to a mixing tank, stir at 20℃ and 400rpm for 25min, and then let stand for 50min to complete hydration to obtain the protein aqueous phase; then add the oil phase concentrate obtained in step 2 to the protein aqueous phase, and perform high shear at 10000rpm for 3min to obtain the colostrum; Step 4: Mix 20g of tea saponin with 90g of 70% ethanol and stir at 40℃ and 400rpm for 15min to obtain a pre-wetted tea saponin concentrate; separately, mix 10g of tea saponin with 120g of purified water and hydrate at 20℃ and 400rpm for 30min to obtain a hydrated tea saponin solution. First, add the pre-wetted tea saponin concentrate to the colostrum obtained in Step 3, shear at 40℃ and 7000rpm for 1min, then keep warm at 400rpm for 8min; then lower the system to 25℃, add the hydrated tea saponin solution within 10min, and continue stirring at 400rpm for 15min to obtain a composite emulsion; Step 5: Add 550g of maltodextrin to the composite emulsion obtained in Step 4, stir at 20℃ and 400rpm for 15min, then homogenize once at 15MPa, and then spray dry to make powder, controlling the inlet air temperature to 145℃ and the outlet air temperature to 75℃, to obtain a natural plant extract composite feed additive that improves the quality of snowflake pork. Step 6: Mix the natural plant extract compound feed additive obtained in Step 5 at a ratio of 1.5 kg per 1000 kg of corn and soybean meal-based fattening basal complete feed, and feed it to fattening pigs weighing 75-115 kg for 42 consecutive days.

[0028] Example 3:

[0029] Step 1: 140g of epigallocatechin gallate hydrate, 210g of vinyl palmitate, 1900g of anhydrous tert-butanol, 110g of 4A molecular sieve, and 65g of immobilized lipase were sequentially added to a reaction flask equipped with a stirrer and reflux device. After purging with nitrogen for 6 minutes, the mixture was reacted at 52℃ and 220rpm for 18 hours. After the reaction was completed, the mixture was filtered while hot. The filter cake was washed once with 110g of anhydrous tert-butanol and the washed cake was added to the filtrate. The tert-butanol was then removed under reduced pressure below 45℃. 330g of n-hexane, pre-cooled to 3℃, was added to the concentrate in two portions, 165g each time. After washing, the washings were discarded to remove unreacted vinyl palmitate. The residue was then dried under vacuum at 37℃ for 13 hours to obtain the partially palmitated polyphenol product. Step 2: Take 160g of the palmitate esterified product of tea polyphenols obtained in Step 1, 65g of L-α-phosphatidylcholine (soybean), 90g of non-GMO soybean oil and 330g of anhydrous ethanol and add them to a jacketed stirring container. Stir at 52℃ and 650rpm for 45min. Then, keep at 52℃ and add 170g of non-GMO soybean oil under reduced pressure while removing ethanol over 22min. Continue stirring for 22min to obtain the oil phase concentrate. Step 3: Add 85g of emulsified soy protein isolate and 1950g of purified water to a mixing tank, stir at 28℃ and 550rpm for 32min, and then let stand for 65min to complete hydration to obtain the protein aqueous phase; then add the oil phase concentrate obtained in step 2 to the protein aqueous phase, and perform high shear at 13000rpm for 5min to obtain the colostrum. Step 4: Mix 32g of tea saponin with 130g of 70% ethanol and stir at 48℃ and 400rpm for 22min to obtain a pre-wetted tea saponin concentrate; separately, mix 15g of tea saponin with 155g of purified water and hydrate at 28℃ and 400rpm for 45min to obtain a hydrated tea saponin solution. First, add the pre-wetted tea saponin concentrate to the colostrum obtained in Step 3, shear at 48℃ and 8500rpm for 2.5min, then keep warm at 550rpm for 12min; then lower the system temperature to 29℃, add the hydrated tea saponin solution within 18min, and continue stirring at 550rpm for 22min to obtain a composite emulsion; Step 5: Add 700g of maltodextrin to the composite emulsion obtained in Step 4, stir at 24℃ and 550rpm for 22min, then homogenize once at 22MPa, and then spray dry to make powder, controlling the inlet air temperature to 155℃ and the outlet air temperature to 82℃, to obtain a natural plant extract composite feed additive that improves the quality of snowflake pork. Step 6: Mix the natural plant extract compound feed additive obtained in Step 5 at a ratio of 1.5 kg per 1000 kg of corn and soybean meal-based fattening basal complete feed, and feed it to fattening pigs weighing 75-115 kg for 42 consecutive days.

[0030] Example 4:

[0031] Step 1: 110g epigallocatechin gallate hydrate, 170g vinyl palmitate, 1700g anhydrous tert-butanol, 90g 4A molecular sieve, and 55g immobilized lipase were sequentially added to a reaction flask equipped with a stirrer and reflux device. After purging with nitrogen for 5 minutes, the mixture was reacted at 48℃ and 190rpm for 14 hours. After the reaction was completed, the mixture was filtered while hot. The filter cake was washed once with 90g anhydrous tert-butanol and the washed cake was added to the filtrate. The tert-butanol was then removed under reduced pressure below 45℃. 270g of n-hexane, pre-cooled to 6℃, was added to the concentrate in two portions, 135g each time. After washing, the washings were discarded to remove unreacted vinyl palmitate. The residue was then dried under vacuum at 32℃ for 11 hours to obtain the partially palmitated polyphenol product. Step 2: Take 145g of the palmitate esterified product of tea polyphenols obtained in Step 1, 55g of L-α-phosphatidylcholine (soybean), 70g of non-GMO soybean oil and 260g of anhydrous ethanol and add them to a jacketed stirring container. Stir at 48℃ and 550rpm for 35min. Then, keep at 48℃ and add 180g of non-GMO soybean oil over 20min while removing ethanol under reduced pressure. Continue stirring for 18min to obtain the oil phase concentrate. Step 3: Add 75g of emulsified soy protein isolate and 1900g of purified water to a mixing tank, stir at 24℃ and 450rpm for 28min, and then let stand for 55min to complete hydration to obtain the protein aqueous phase; then add the oil phase concentrate obtained in step 2 to the protein aqueous phase, and perform high shear at 11000rpm for 4min to obtain the colostrum. Step 4: Mix 28g of tea saponin with 100g of 70% ethanol and stir at 43℃ and 400rpm for 18min to obtain a pre-wetted tea saponin concentrate; separately, mix 18g of tea saponin with 170g of purified water and hydrate at 24℃ and 400rpm for 35min to obtain a hydrated tea saponin solution. First, add the pre-wetted tea saponin concentrate to the colostrum obtained in Step 3, shear at 43℃ and 7500rpm for 1.5min, then keep warm at 450rpm for 9min; then lower the system temperature to 27℃, add the hydrated tea saponin solution within 12min, and continue stirring at 450rpm for 18min to obtain a composite emulsion; Step 5: Add 600g of maltodextrin to the composite emulsion obtained in Step 4, stir at 23℃ and 450rpm for 18min, then homogenize once at 18MPa, and then spray dry to make powder, controlling the inlet air temperature at 148℃ and the outlet air temperature at 77℃ to obtain a natural plant extract composite feed additive that improves the quality of snowflake pork. Step 6: Mix the natural plant extract compound feed additive obtained in Step 5 at a ratio of 1.5 kg per 1000 kg of corn and soybean meal-based fattening basal complete feed, and feed it to fattening pigs weighing 75-115 kg for 42 consecutive days.

[0032] Example 5:

[0033] Step 1: 130g epigallocatechin gallate hydrate, 220g vinyl palmitate, 2000g anhydrous tert-butanol, 120g 4A molecular sieve, and 70g immobilized lipase were sequentially added to a reaction flask equipped with a stirrer and reflux device. Nitrogen gas was introduced for 8 minutes, and the mixture was reacted at 55℃ and 250rpm for 20 hours. After the reaction was completed, the mixture was filtered while hot. The filter cake was washed once with 120g anhydrous tert-butanol and the washed cake was added to the filtrate. The tert-butanol was then removed under reduced pressure below 45℃. 360g of n-hexane pre-cooled to 0℃ was added to the concentrate in two portions, 180g each time. The washings were discarded to remove unreacted vinyl palmitate. The residue was then dried under vacuum at 40℃ for 14 hours to obtain the partially palmitated polyphenol product. Step 2: Take 170g of the palmitate esterified product of tea polyphenols obtained in Step 1, 70g of L-α-phosphatidylcholine (soybean), 100g of non-GMO soybean oil and 360g of anhydrous ethanol and add them to a jacketed stirring container. Stir at 55℃ and 700rpm for 50min. Then, while maintaining 55℃, add 180g of non-GMO soybean oil under reduced pressure while removing ethanol over 25min. Continue stirring for 25min to obtain the oil phase concentrate. Step 3: Add 90g of emulsified soy protein isolate and 2000g of purified water to a mixing tank, stir at 30℃ and 600rpm for 35min, and then let stand for 70min to complete hydration to obtain the protein aqueous phase; then add the oil phase concentrate obtained in step 2 to the protein aqueous phase, and perform high shear at 14000rpm for 5min to obtain the colostrum. Step 4: Mix 35g of tea saponin with 140g of 70% ethanol and stir at 50℃ and 400rpm for 25min to obtain a pre-wetted tea saponin concentrate; separately, mix 12g of tea saponin with 180g of purified water and hydrate at 30℃ and 400rpm for 50min to obtain a hydrated tea saponin solution. First, add the pre-wetted tea saponin concentrate to the colostrum obtained in Step 3, shear at 50℃ and 9000rpm for 3min, then keep warm at 600rpm for 10min; then lower the system temperature to 30℃, add the hydrated tea saponin solution within 20min, and continue stirring at 600rpm for 25min to obtain a composite emulsion; Step 5: Add 750g of maltodextrin to the composite emulsion obtained in Step 4, stir at 25℃ and 600rpm for 25min, then homogenize once at 25MPa, and then spray dry to make powder, controlling the inlet air temperature to 155℃ and the outlet air temperature to 80℃, to obtain a natural plant extract composite feed additive that improves the quality of snowflake pork. Step 6: Mix the natural plant extract compound feed additive obtained in Step 5 at a ratio of 1.5 kg per 1000 kg of corn and soybean meal-based fattening basal complete feed, and feed it to fattening pigs weighing 75-115 kg for 42 consecutive days.

[0034] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that: step 1 does not involve esterification, and in step 2, 150g of epigallocatechin gallate hydrate is used instead of 150g of the tea polyphenol partial palmitate esterification product obtained in step 1, while the other conditions are the same as in Example 1.

[0035] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the reaction time in step 1 at 50°C and 200 rpm was changed from 16 h to 8 h, while the other conditions were the same as in Example 1.

[0036] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the reaction time in step 1 at 50°C and 200 rpm was changed from 16 h to 24 h, while the other conditions were the same as in Example 1.

[0037] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that 60g of L-α-phosphatidylcholine (soybean) is not added in step 2, but instead 60g of non-GMO soybean oil of the same mass is added to keep the total amount of non-GMO soybean oil added in step 2 consistent. The other conditions are the same as in Example 1.

[0038] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that in step 2, 150g of the partially palmitated product of tea polyphenols obtained in step 1, 60g of L-α-phosphatidylcholine (soybean), 240g of non-GMO soybean oil and 300g of anhydrous ethanol were mixed at one time, stirred at 50°C and 600rpm for 40min, and then the ethanol was removed directly under reduced pressure. Non-GMO soybean oil was not added in stages. The other conditions were the same as in Example 1.

[0039] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that: in step 4, no hydrated tea saponin solution is prepared; instead, 45g of tea saponin is mixed with 120g of 70% ethanol and stirred at 45°C and 400rpm for 20min, and then added to the pre-emulsion obtained in step 3 all at once. At the same time, 150g of purified water originally used to prepare the hydrated tea saponin solution is directly added to the pre-emulsion obtained in step 3 to keep the total amount of ethanol and purified water added to the system in step 4 the same as in Example 1. The other conditions are the same as in Example 1.

[0040] Comparative Example 7: The difference between Comparative Example 7 and Example 1 is that: in step 4, no pre-wetted tea saponin concentrate is prepared; instead, 45g of tea saponin is mixed with 150g of purified water and hydrated at 25°C and 400rpm for 40min, and then added to the pre-emulsion obtained in step 3 all at once. At the same time, 120g of 70% ethanol originally used to prepare the pre-wetted tea saponin concentrate is directly added to the pre-emulsion obtained in step 3 to keep the total amount of ethanol and purified water added to the system in step 4 the same as in Example 1, and the other conditions are the same as in Example 1.

[0041] Comparative Example 8: The difference between Comparative Example 8 and Example 1 is that in step 4, the hydrated tea saponin solution is first added to the colostrum obtained in step 3, and stirred at 28°C and 500 rpm for 20 min. Then, the pre-wetted tea saponin concentrate is added and sheared at 45°C and 8000 rpm for 2 min. Subsequently, it is kept at 500 rpm for 10 min. The remaining conditions are the same as in Example 1.

[0042] Performance testing: Preparation and source of test samples: The test samples included the natural plant extract compound feed additives obtained in step 5 of Examples 1-5 and Comparative Examples 1-8. All samples were prepared using the same batch of raw materials, the same homogenizing equipment, and the same spray-drying equipment. The spray-dried powder was collected, passed through a 40-mesh sieve, placed in aluminum foil composite bags, and stored at 25℃ in the dark for no more than 7 days for intrinsic characterization. Separately, each sample was mixed with 1.5 kg of the additive per 1000 kg of corn-soybean meal-based fattening basal complete feed to prepare experimental diets. Except for the additives, the raw material composition, batch, particle size, and mixing time of the basal complete feeds in each group were completely identical. 156 healthy Snowflake pigs with the same genetic background and a weight of 75.0 ± 2.0 kg were randomly divided into 13 groups of 12 pigs each, half male and half female, according to the principles of weight, sex, and litter balance. Each group had 6 replicate pens with 2 pigs per pen. Feed and water were provided freely for 42 consecutive days. After the experiment, 6 animals were randomly selected from each group, fasted for 12 hours and then slaughtered. The longissimus dorsi muscle was taken from the left carcass between the last thoracic vertebra and the first lumbar vertebra as meat quality test samples. Samples used for marbling and drip loss determination were stored at 4℃. Samples used for intramuscular fat and fatty acid determination were chopped after removing visible outer fat and connective tissue, quick-frozen in liquid nitrogen and stored at -80℃.

[0043] Test Item 1: Esterification Conversion Rate. Take 10 mg of the palmitate esterified product of tea polyphenols obtained in Step 1 of the Examples and Comparative Examples, place it in a 10 mL volumetric flask, add acetonitrile-methanol-water mixed solvent to make up to volume, wherein the volume ratio of acetonitrile, methanol and water is 40:20:40, mix well and sonicate for 10 min to ensure the sample is fully dispersed and dissolved; then filter through a 0.22 μm polytetrafluoroethylene filter membrane to obtain the test solution; separately, take 10 mg of epigallocatechin gallate hydrate standard that has not undergone palmitate esterification reaction, accurately weigh it, and make up to 10 mL with the same solvent to obtain the control stock solution. A series of standard solutions with mass concentrations of 10 μg / mL, 20 μg / mL, 40 μg / mL, 60 μg / mL, 80 μg / mL, and 100 μg / mL were prepared to plot standard curves. A reversed-phase high-performance liquid chromatograph (RP-HPLC) was used with a C18 column (4.6 mm × 250 mm, 5 μm particle size); the column temperature was 30℃; mobile phase A was an aqueous solution containing 0.2% formic acid, and mobile phase B was acetonitrile containing 0.2% formic acid; the flow rate was 1.0 mL / min; the detection wavelength was 275 nm; and the injection volume was 10 μL. The gradient elution program was set as follows: 0-10 min, phase B linearly increased from 8% to 20%; 10-25 min, phase B linearly increased from 20% to 45%; 25-40 min, phase B linearly increased from 45% to 88%; 40-45 min, phase B maintained at 88%; 45-50 min, phase B recovered to 8% and equilibrated. A peak area-mass concentration standard curve was established using epigallocatechin gallate hydrate standard solution. The initial concentration C0 of epigallocatechin gallate hydrate in the original reaction solution and the concentration C of residual epigallocatechin gallate hydrate in the product sample were determined. t The esterification conversion rate is calculated using the following formula: Esterification conversion rate (%) = (C0 - C t ) / C0×100%; the same sample was prepared and tested in parallel 3 times, and the arithmetic mean was taken as the esterification conversion rate of the sample; the relative standard deviation of the 3 parallel determinations was not greater than 3.0%.

[0044] Test Item 2: Conventional Composition of Finished Product Additives. All test samples were pulverized and passed through a 0.425mm sieve. Moisture content was determined according to GB / T 6435-2014, crude protein according to GB / T 6432-2018, crude fat according to GB / T 6433-2025, and crude fiber according to GB / T 6434-2022. Each sample was weighed in triplicate, and the results were expressed as the arithmetic mean of the three parallel determinations. The results are shown in Table 1.

[0045] Test Item 3: Average Particle Size and Polydispersity Index after Reconstitution. Weigh 1.00 g of each test sample, add 99.00 g of purified water, stir for 30 min at 25℃ and 500 rpm, and then let stand for 10 min to allow the sample to fully reconstitute. Dilute the reconstituted solution with purified water to a solids mass fraction of 0.05%. Determine the average particle size and polydispersity index using the dynamic light scattering method according to GB / T 29022-2021. The detection temperature is 25℃. Each sample is measured in triplicate. The results are shown in Table 1.

[0046] Test Item 4: Zeta Potential. Take 10 mL of the reconstituted solution obtained from Test Item 3, and dilute it to 50 mL with 1 mmol / L potassium chloride solution. Measure the zeta potential at 25℃ according to GB / T 32671.2-2019, and follow the requirements for electric pool cleaning, sample degassing, and repeated determination according to GB / Z 42353-2023. Each sample was measured three times consecutively, and the average value was taken as the result. The results are shown in Table 1.

[0047] Test Item 5: Peroxide value and acid value of oils extracted after accelerated storage. 20.00 g of each test sample was weighed and spread evenly in a brown glass petri dish. The samples were placed in a constant temperature incubator at 40±1℃ and stored in the dark for 14 days. Samples were taken on day 0 and day 14. The extracted samples were subjected to Soxhlet extraction with petroleum ether for 6 hours to recover the oil. The rotary evaporation temperature was controlled below 45℃ to obtain the oil to be tested. After oil extraction, the peroxide value was determined according to GB 5009.227-2023, and the acid value was determined according to GB 5009.229-2025. Three replicates were performed at each time point. The results are shown in Table 1.

[0048] Test item six: Marbling of pork. The test was conducted according to NY / T 821-2019. After 30 minutes of oxygenation on a fresh section of the longissimus dorsi muscle 24 hours post-slaughter, the marbling was scored according to the marbling scoring chart. The results are shown in Table 2.

[0049] Test item seven: Drip loss. The test was conducted according to NY / T 821-2019. Each longissimus dorsi muscle sample was trimmed into a 5.0cm × 3.0cm × 1.0cm strip along the muscle fiber direction. After absorbing surface free water, the initial weight (m1) was measured. The sample was then suspended in a sealed plastic bag, ensuring it did not touch the bag wall, and placed at 4℃ for 48 hours. After removal, the surface exudate was gently wiped away, and the final weight (m2) was measured. Drip loss was calculated as (m1-m2) / m1 × 100%, and the results are shown in Table 2.

[0050] Test Item 8: Intramuscular Fat Content and Fatty Acid Composition. After removing the visible outer layer of fat from the longissimus dorsi muscle sample, the sample was minced and freeze-dried. The intramuscular fat content was first determined according to GB 5009.6-2025. Then, the fatty acids in the sample were methylated according to GB 5009.168-2016 and analyzed by gas chromatography. The contents of palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1n9c), linoleic acid (C18:2n6c), as well as ΣSFA, ΣMUFA, and ΣPUFA were statistically analyzed. The results are shown in Table 2.

[0051] Table 1. Intrinsic Characterization Results of Samples

[0052] Table 2 Application Test Results

[0053] Data Analysis: Table 1 shows that epigallocatechin gallate hydrate, after partial palmitate esterification, forms a stable associated structure with L-α-phosphatidylcholine (soybean). After staged addition of non-GMO soybean oil and two states of tea saponins, a smaller and more uniform reconstituted dispersion system is obtained, while maintaining high interfacial electrostability and good storage antioxidant capacity. This structural characteristic is not limited to the formulation level but is further reflected in application indicators such as marbling, drip loss, intramuscular fat, and fatty acid composition, as shown in Table 2. This indicates that the present invention improves effective delivery and bioavailability by improving interfacial structure and reducing the risk of inactivation of active components during processing and storage, thereby achieving synergistic optimization of lipid deposition, muscle water retention, and targeted regulation of fatty acids within the same system. It can be seen that the present invention does not rely on the simple supplementation of a single component, but rather on partial palmitate esterification, phospholipid association, staged oil addition, and the sequential compounding of two states of tea saponins to jointly construct a stable delivery system, ultimately demonstrating a significant synergistic effect in improving the quality of marbled pork.

[0054] As can be seen from the data in Tables 1 and 2 for Example 1 and Comparative Example 1, when epigallocatechin gallate hydrate was not partially palmitized, the samples showed weaknesses in reconstitution particle size, dispersion uniformity, interfacial electrostability, and oxidation control during storage. This is further reflected in applications, resulting in insufficient improvement in marbling, limited intramuscular fat accumulation, unsatisfactory control of drip loss, and minimal optimization of fatty acid composition. The main reason for this is that in the unesterified state, the relevant active components lack sufficient affinity for the oil phase and interface, making it difficult to stably distribute at the emulsion droplet interface and hindering effective delivery during subsequent digestion and absorption.

[0055] As can be seen from the data in Tables 1 and 2 for Example 1, Comparative Example 2, and Comparative Example 3, both excessively low and excessively high degrees of esterification are detrimental to the full realization of the overall effect. When esterification is insufficient, the lipid affinity of epigallocatechin gallate hydrate remains limited, resulting in insufficient improvement in reconstitution stability and storage stability as shown in Table 1, which in turn limits the enhancement of intramuscular fat deposition and marbling as shown in Table 2. When esterification is excessive, although some dispersion indicators may improve compared to insufficient esterification, the reduced number of retained free phenolic hydroxyl groups weakens interfacial synergy and subsequent biological regulatory capacity, ultimately failing to simultaneously translate into better application results.

[0056] As can be seen from the data in Tables 1 and 2 for Example 1 and Comparative Examples 4 and 5, L-α-phosphatidylcholine (soybean) and the process route of first associating and then adding oil play an important role in the overall effect of this invention. When L-α-phosphatidylcholine (soybean) is missing, even if the total amount of oil phase is replenished, the reconstitution dispersibility, interfacial potential, and storage stability in Table 1 are still difficult to reach the levels of the examples, indicating that this component is not only part of the oil phase composition but also plays a role in interfacial association and structural pre-organization. If the staged addition of non-GMO soybean oil is cancelled, the already formed associated structure is difficult to be fully preserved in the subsequent phase inversion process, which will also weaken the ability to form a uniform dispersion system as shown in Table 1. These differences are further reflected in Table 2, limiting the improvement in marbling, intramuscular fat, and fatty acid composition.

[0057] As can be seen from the data in Tables 1 and 2 for Example 1 and Comparative Examples 6, 7, and 8, not only do pre-wetted tea saponins and hydrated tea saponins need to be present simultaneously, but their order of addition also directly affects the final effect. When only one state of tea saponin is used, the particle size control, dispersion uniformity, and interfacial electrostability in Table 1 are not comparable to those of Example 1, indicating that a single state of tea saponin can only cover part of the requirements in the interface construction process and is difficult to simultaneously address initial insertion, outer hydration protection, and long-term stability. Furthermore, Table 2 shows that this insufficient interface construction will continue to manifest as a decrease in intramuscular fat gain, weakened control of drip loss, and insufficient optimization of fatty acid composition. Even if both states of tea saponin are present simultaneously, if the order of addition is reversed, the hierarchical construction effect of the interface will be weakened, indicating that the present invention does not rely on simple mixing, but rather on a structural construction process with clearly defined order requirements.

[0058] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A compound feed additive of natural plant extracts for improving the quality of marbled pork, characterized in that, The product is prepared by mass parts from the following raw materials: 130-170 parts of tea polyphenols partially palmitated esters, 50-70 parts of L-α-phosphatidylcholine, 200-280 parts of non-GMO soybean oil, 70-90 parts of emulsified soy protein isolate, 30-47 parts of tea saponins and 550-750 parts of maltodextrin. The partially palmitated product is obtained by partial esterification of epigallocatechin gallate hydrate and vinyl palmitate under the catalysis of immobilized lipase; the non-GMO soybean oil includes a first portion of non-GMO soybean oil and a second portion of non-GMO soybean oil, wherein the first portion of non-GMO soybean oil, together with the partially palmitated product and L-α-phosphatidylcholine, forms an oil phase, and the second portion of non-GMO soybean oil is added to the oil phase during the ethanol removal process; the tea saponin includes pre-wetted tea saponin and hydrated tea saponin, wherein the pre-wetted tea saponin is first added to the colostrum formed by the oil phase and the aqueous phase of emulsified soy protein isolate, and the hydrated tea saponin is added later; the compound feed additive is a powder obtained by homogenization and spray drying.

2. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The first part is 60-100 parts of non-GMO soybean oil, the second part is 140-180 parts of non-GMO soybean oil, and 240-360 parts of anhydrous ethanol are added during the formation of the oil phase.

3. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The partially palmitated ester product was prepared by the following method: 100-140 parts of epigallocatechin gallate hydrate, 150-220 parts of vinyl palmitate, 1600-2000 parts of anhydrous tert-butanol, 80-120 parts of 4A molecular sieve and 50-70 parts of immobilized lipase were mixed and reacted at 45-55℃ and 180-250rpm for 12-20h; after the reaction, the product was obtained by hot filtration, removal of tert-butanol under reduced pressure, washing with n-hexane and vacuum drying at 30-40℃.

4. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The esterification conversion rate of the partially palmitated products is 45.1%-70.6%.

5. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The total mass of the pre-wetted tea saponin and the hydrated tea saponin is 30-47 parts, and the mass ratio of the two is 1.5:1-3:

1.

6. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The pre-wetted tea saponin is obtained by mixing 20-35 parts of tea saponin with 90-140 parts of 70% ethanol by mass, and the hydrated tea saponin is obtained by mixing 10-18 parts of tea saponin with 120-180 parts of purified water.

7. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The immobilized lipase was derived from Candida antarctica and had a specific activity greater than 2 U / mg.

8. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The emulsified soy protein isolate aqueous phase is formed by hydrating 70-90 parts of emulsified soy protein isolate with 1800-2000 parts of purified water.

9. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The homogenization process involves homogenizing once at 15-25 MPa.

10. The natural plant extract compound feed additive for improving the quality of marbled pork according to claim 1, characterized in that, The spray drying process involves an inlet air temperature of 145-155℃ and an outlet air temperature of 75-82℃.

Images