Feed water-soluble fat powder with high lactose content and high protein content and preparation method of feed water-soluble fat powder

Abstract

The invention discloses a high-lactose high-protein-content water-soluble fat powder for feed and a preparation method thereof. The fat powder comprises the following components in parts by weight: 10-25 parts of fat core, 35-55 parts of lactose, 20-35 parts of protein and 5-15 parts of carrier auxiliary materials. The preparation method adopts a composite process, and comprises the key steps of low-temperature homogeneous emulsification, primary spray granulation to form a primary shell layer, film condensation reinforcement to vitrify lactose, and secondary micro-spray-vacuum drying to form the sealed microcapsule.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of fat powder, and specifically, it is a water-soluble fat powder for feeding with high lactose and high protein content and a preparation method thereof. Background Art

[0002] In modern intensive livestock farming, energy and protein are key nutrients that determine the growth performance, health status and feed utilization efficiency of animals. As the nutrient with the highest energy density (about 2.25 times that of carbohydrates and proteins), adding fat powder to feed has become a common means to increase the energy concentration of the diet and improve the production performance of animals. Especially in the early growth stage of young animals (such as calves, lambs, piglets), their digestive systems are not yet fully developed, and there are special requirements for the types, forms and digestion rates of nutrients.

[0003] Traditional fat powders for feeding, such as hydrogenated fat, calcium soap fat, ordinary spray-dried fat powder, etc., although they can provide energy, generally have one or more of the following problems:

[0004] 1. Low encapsulation rate: The fat encapsulation rate of many conventional fat powders is less than 70%, resulting in some fat being exposed, which is prone to oxidative rancidity during storage and transportation, affecting the product quality and palatability, and even producing toxic and harmful substances.

[0005] 2. Poor water solubility: Most fat powders have poor dispersibility in water and are difficult to dissolve quickly or form a uniform emulsion. For young animals that rely on liquid feed (such as milk replacer), this will affect their feeding, digestion and absorption.

[0006] 3. Insufficient or lack of lactose and protein content: Lactose is the main carbohydrate in the colostrum and normal milk of young mammals (especially ruminants). It not only provides a quick source of energy, but also plays an important role in maintaining intestinal health and promoting the growth of beneficial bacteria. High-quality protein (such as whey protein) provides essential amino acids and is crucial for the tissue and organ development and immune system construction of young animals. Conventional fat powders usually only focus on the fat itself and ignore the synergistic nutritional value of lactose and protein for young animals.

[0007] 4. Low digestion and absorption efficiency: For young animals with an underdeveloped digestive enzyme system, large particles or fats that are not easily emulsified are difficult to be digested and absorbed efficiently, which may lead to nutritional waste and even diarrhea.

[0008] In order to make up for the above deficiencies, some studies have tried to directly physically blend lactose powder or protein powder into the fat powder. However, this simple mixing method has poor effects, because:

[0009] 1. Fat core exposure: Simple physical mixing cannot effectively protect the fat core, and the risk of oxidative rancidity still exists.

[0010] 2. Moisture absorption and caking: Lactose has strong hygroscopicity, and direct blending easily causes the entire powder product to absorb moisture and cake, affecting fluidity and usability.

[0011] 3. Component stratification: Differences in the density and particle size of different materials may lead to stratification during transportation or use, resulting in uneven nutrient composition during actual feeding.

[0012] 4. Poor processing performance: High proportions of free lactose and protein powder mixtures may exhibit problems such as coking and excessive Maillard reactions during subsequent feed processing such as granulation or puffing.

[0013] Young ruminants (such as calves and lambs) during the weaning transition period have not fully established rumen function and still have relatively high requirements for lactose and milk protein from milk. Lactose can provide energy for the development of rumen epithelial cells, while whey protein provides highly digestible high-biological-value protein. At the same time, they require a fat source that is easy to emulsify and absorb to meet the energy requirements for rapid growth. Therefore, developing a new type of feed fat powder that can organically combine high-content lactose, high-quality protein, and high-energy fat, and endow the product with excellent water solubility, high encapsulation rate, and stability, has important scientific significance and great market application value for improving the nutritional level of young animals and promoting their healthy growth.

[0014] Currently, there is a lack of ideal fat powder products on the market that can simultaneously meet the five major requirements of high lactose, high protein, high energy, high water solubility, and high stability. The existing technology urgently needs an innovative formula and process to address the above challenges. Summary of the Invention

[0015] The present invention aims to overcome the defects of existing feed fat powders, such as low encapsulation rate, poor water solubility, insufficient lactose and protein content, poor stability, and difficulty in meeting the special nutritional requirements of young animals (especially ruminants). Specifically, the technical problem to be solved by the present invention is to provide a new type of feed water-soluble fat powder that is rich in both lactose and protein, has excellent instantaneous water solubility, high fat encapsulation rate, good thermal stability and acid stability, and can significantly improve the growth performance of young animals. At the same time, the present invention also provides a preparation method for the feed water-soluble fat powder with high lactose and high protein content.

[0016] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0017] In the first aspect, the present invention provides a feed water-soluble fat powder with high lactose and high protein content, characterized in that, by weight, the fat powder is composed of the following components:

[0018] Fat core: 10 - 25 parts, preferably 15 - 20 parts;

[0019] Lactose: 35 - 55 parts, preferably 40 - 45 parts;

[0020] Protein: 20 - 35 parts, preferably 25 - 30 parts;

[0021] Carrier excipient: 5 - 15 parts, preferably 8 - 12 parts.

[0022] Furthermore, the fat core is preferably medium-chain triglycerides (MCT) with a saturation not less than 98%. Medium-chain triglycerides are more easily digested and absorbed by young animals, providing energy quickly. Refined vegetable oils from other sources (such as coconut oil, palm kernel oil) or animal fats can also be used.

[0023] Furthermore, the lactose is preferably ultrafiltration desalted lactose powder with a purity not less than 99%. High-purity lactose can provide a purer energy source and reduce the impact of impurities on product stability.

[0024] Furthermore, the protein is preferably whey protein isolate (WPIs) by low-temperature spray drying, with a protein content not less than 90%. Whey protein isolate has a high biological value and good emulsifying and film-forming properties, which helps in the encapsulation of fat and product stability. Whey protein concentrate (WPC), sodium caseinate, or other high-quality plant proteins (such as soy protein isolate) can also be used.

[0025] Furthermore, the carrier excipient is selected from one or a combination of corn maltodextrin, microcrystalline cellulose, and food-grade lecithin.

[0026] Preferably, the corn maltodextrin has a relatively high DE value (for example, the DE value is 15 - 25), which helps to improve solubility and form a stable emulsion.

[0027] Preferably, as an emulsifier, the addition amount of lecithin is 1 - 10% of the weight of the fat core, preferably 2 - 5%.

[0028] Preferably, as a glidant and structure stabilizer, the addition amount of microcrystalline cellulose is 0.5 - 5% of the total dry matter weight, preferably 1 - 3%.

[0029] In a preferred embodiment, in the precursor emulsion, the mass ratio of lactose, whey protein, and fat core is (2.5 - 3.5):(1.5 - 2.5):1, more preferably 3:2:1. This ratio is calculated based on the dry matter weight.

[0030] The water-soluble fat powder for feed with high lactose and high protein content described in the present invention has a lactose content of up to 38 - 45% (w / w), a protein content of up to 25 - 30% (w / w) in its final product, an oil encapsulation rate of not less than 90%, preferably not less than 92%. Its instantaneous water solubility index in water at 25°C is not less than 95% within 5 seconds, preferably not less than 97%.

[0031] In a second aspect, the present invention provides a method for preparing the water-soluble fat powder for feed with high lactose and high protein content, which is characterized by comprising the following steps:

[0032] (1) Raw material pretreatment and emulsion preparation:

[0033] a. Oil phase preparation: Heat the metered fat core (such as medium-chain triglycerides) to 40 - 60°C to make it liquid. If lecithin is used as an emulsifier, dissolve it in the fat core and mix evenly.

[0034] b. Preparation of aqueous phase A (protein phase): Dissolve the metered protein (such as whey protein isolate) and part of the carrier excipient (such as maltodextrin) in deionized water, control the water temperature at 30 - 50°C, and stir until completely dissolved to form a protein phase solution. The amount of water used is preferably such that the total solids content of the emulsion is 30 - 50% (w / w).

[0035] c. Preparation of aqueous phase B (lactose phase): Dissolve or disperse the metered lactose and the remaining carrier excipient (such as microcrystalline cellulose) in another portion of deionized water, control the water temperature at 40 - 60°C, and stir until completely dissolved or evenly dispersed to form a lactose phase solution / suspension.

[0036] d. Mixing and primary emulsification: Mix aqueous phase A and aqueous phase B evenly, and then slowly add the prepared oil phase under high-speed shearing (such as 5000 - 10000 rpm, for 2 - 5 minutes) to conduct primary emulsification to obtain a primary emulsion. At this time, the dry matter mass ratio of lactose, whey protein and fat core in the emulsion is controlled according to a preset ratio (such as 3:2:1).

[0037] (2) Low-temperature homogenization and emulsification:

[0038] Cool the primary emulsion obtained in step (1) to 5 - 15°C, preferably 8 - 12°C, and then conduct homogenization treatment through a high-pressure homogenizer. The homogenization pressure is controlled at 20 - 30 MPa, preferably 25 MPa, and 1 - 3 cycles are carried out, preferably 2 cycles. An O / W type emulsion with fine particle size and uniform distribution is obtained. Low-temperature operation helps to protect protein activity and prevent fat oxidation.

[0039] (3) Spray granulation for the first time to form a primary shell layer:

[0040] Pump the homogeneous emulsion obtained in step (2) into a spray drying tower for the first spray drying granulation. The inlet air temperature of the spray drying is controlled at 130 - 160 °C, preferably 140 °C; the outlet air temperature is controlled at 60 - 75 °C, preferably 65 °C. The main purpose of this step is to form a preliminary coating on the fat core by using proteins and part of the maltodextrin to form primary shell particles with a certain strength.

[0041] (4)Thin-film condensation enhancement and lactose vitrification:

[0042] Rapidly perform low-temperature treatment on the primary coated particles obtained in step (3) (at this time, lactose is mainly distributed on the surface or near the surface of the particles), so that the lactose on the surface or surface layer is quickly cooled and undergoes vitrification transformation. The specific operation is as follows: Carry out thin-film condensation or fluidized bed cold air drying treatment on the particles for 30 - 60 minutes, preferably 45 minutes, in an environment of -25 °C to -15 °C, preferably -20 °C. The purpose of this step is to quickly form an amorphous glassy structure of lactose by using low temperature, enhance the denseness of the shell layer, reduce the hygroscopicity and lock the primary shell layer.

[0043] (5)Secondary microspray - vacuum drying to form sealed microcapsules:

[0044] a. Option one (if the moisture content of the particles is still high after step (4) or further enhanced coating is required): Mix the particles treated in step (4) with a small amount of additional wall material solution (such as maltodextrin solution or whey protein solution, solid content 5 - 15%), carry out secondary microspray, and then carry out vacuum drying.

[0045] b. Preferred option two: Directly carry out secondary spray drying or vacuum drying on the particles with enhanced vitrified lactose obtained in step (4) (if the moisture content is already low, direct vacuum drying can be carried out). The combination of "secondary microspray - vacuum drying" can be used, that is, the particles after condensation enhancement are dispersed again (if necessary, a small amount of water or binder solution can be added to form a slurry), and then secondary spray is carried out, but the conditions for this spray are milder, for example, the inlet air temperature is 100 - 125 °C (preferably 115 °C), and drying is carried out under a lower pressure (such as a vacuum degree of 0.04 - 0.08 MPa, preferably 0.06 MPa), or directly use vacuum freeze-drying or vacuum drying. The purpose of this step is to further remove moisture, form a dense, stable and well-sealed microcapsule structure, and ensure that the fat core is effectively coated by the lactose - protein gradient shell layer.

[0046] (6)Post-treatment:

[0047] Cool and screen the dried fat powder product (for example, 80 - 120 mesh) to obtain the final high-lactose and high-protein content feed water-soluble fat powder. Inspect the various indicators of the product, and after passing the inspection, package and store it.

[0048] Compared with the prior art, the water-soluble fat powder for feed with high lactose and high protein content provided by the present invention and its preparation method have the following remarkable beneficial effects:

[0049] High nutritional density and synergistic effect: Through precise formulation design, the product of the present invention has a lactose content as high as 40.7% (dry basis, the same below), a protein content as high as 27.5%, and the fat content can also meet the energy requirements (for example, 15 - 20%). This combination of high lactose, high protein, and high energy can synergistically meet the special nutritional requirements of young animals, especially ruminants in the early stage, for lactose (promoting rumen development and providing quick energy), high-quality protein (promoting growth and immunity), and fat (providing concentrated energy).

[0050] Extremely high fat embedding rate: The "biphasic lactose - whey protein coating - multi-stage spray condensation" composite process is adopted, especially the lactose vitrification and secondary drying strengthening steps, to form a dense gradient shell structure, so that the embedding rate of the fat core is as high as 92.7%, far higher than that of conventional fat powders (usually <70%). The high embedding rate effectively prevents fat oxidation and rancidity, and ensures the product quality and storage stability.

[0051] Solving the technical problems of the high-lactose system: Through low-temperature thin-film condensation to vitrify lactose, the technical problems of easy moisture absorption, caking in the high-lactose system, and package rupture caused by lactose crystallization are effectively solved, ensuring the fluidity and stability of the powder. Specific embodiments

[0052] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further details the present invention with reference to specific embodiments. It should be understood that the specific embodiments herein are only used to explain the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0053] Unless otherwise specified, the percentages used in the embodiments of the present invention are all mass percentages, and the raw materials used are all commercially available or prepared by conventional methods in the art.

[0054] Example 1: Preparation of water-soluble fat powder for feed with high lactose and high protein content

[0055] 1.1 Preparation of raw materials:

[0056] Fat core: Pharmaceutical-grade medium-chain triglycerides, 16.7 kg.

[0057] Main raw materials for lactose phase: Ultrafiltration desalted lactose powder, 50.0 kg.

[0058] Main raw materials for protein phase: Low-temperature spray whey protein isolate, 33.3 kg.

[0059] Carrier excipients:

[0060] Corn maltodextrin: 8.0 kg.

[0061] Microcrystalline cellulose: 1.5 kg.

[0062] Food-grade soy lecithin: 0.5 kg.

[0063] Solvent: Appropriate amount of deionized water.

[0064] With the above ratios, the dry matter mass ratio of lactose: whey protein: fat core is approximately 3:2:1.

[0065] The total dry matter is approximately: 16.7 (MCT) + 50.0 (lactose) + 33.3 (WPI) + 8.0 (maltodextrin) + 1.5 (MCC) + 0.5 (lecithin) = 110 kg.

[0066] The theoretical content of each main component in the final product (calculated based on dry matter):

[0067] Lactose: (50.0 / 110) × 100% ≈ 45.5%

[0068] Protein (from WPI): (33.3 × 90% / 110) × 100% ≈ 27.2%

[0069] Fat (MCT): (16.7 / 110) × 100% ≈ 15.2%

[0070] 1.2 Preparation process flow:

[0071] (1) Raw material pretreatment and emulsion preparation:

[0072] a. Oil phase preparation: Heat 16.7 kg of MCT to 50 °C, add 0.5 kg of soy lecithin, stir and dissolve evenly, and keep warm for standby.

[0073] b. Aqueous phase A (protein phase) preparation: Take 120 kg of deionized water, heat it to 45 °C, add 33.3 kg of WPIs and 4.0 kg of corn maltodextrin, and stir with a stirrer at low speed until completely dissolved to form a protein phase solution.

[0074] c. Aqueous phase B (lactose phase) preparation: Take another 100 kg of deionized water, heat it to 55 °C, add 50.0 kg of lactose powder, 4.0 kg of corn maltodextrin and 1.5 kg of microcrystalline cellulose, and stir with a stirrer until the lactose is completely dissolved and the microcrystalline cellulose is evenly dispersed to form a lactose phase solution / suspension.

[0075] d. Mixing and primary emulsification: Mix the prepared aqueous phase A and aqueous phase B evenly in an emulsification tank with high-speed shearing function. Then turn on the high-speed shearing device (rotation speed 8000 rpm), slowly pump the thermally insulated oil phase into the mixed aqueous phase, and continuously shear and emulsify for 5 minutes to obtain a primary emulsion. At this time, the total solid content of the emulsion is approximately (110 kg / (110 kg + 120 kg + 100 kg)) × 100% ≈ 33.3%.

[0076] (2) Low-temperature homogenization and emulsification:

[0077] Quickly cool the above primary emulsion to 8 °C through a plate heat exchanger or jacket cooling. Then pump it into a high-pressure homogenizer (such as APV or Niro Soavi brand), and perform 2 cycles of homogenization at a homogenization pressure of 25 MPa. Obtain a milky white, uniform and delicate O / W type emulsion.

[0078] (3) Primary spray granulation to form a primary shell:

[0079] Feed the homogenized emulsion into a centrifugal spray drying tower (such as GEA Niro Minor type) through a peristaltic pump for the first spray drying. Set the process parameters: inlet air temperature 140 °C, outlet air temperature 65 °C, rotation speed of the centrifugal atomizer 18000 rpm. Collect the primary particle powder obtained by drying. The surface of this particle is rich in whey protein and maltodextrin, and MCT is coated inside.

[0080] (4) Film condensation enhancement and lactose vitrification:

[0081] Quickly transfer the primary particle powder collected in step (3) (at this time, most of the lactose tends to accumulate on the particle surface or subsurface due to the solubility gradient and migration during the drying process) to a fluidized bed cold air dryer pre-cooled to -20 °C (or spread it out in a shallow tray in a cold storage and blow it with forced cold air), and perform low-temperature treatment for 45 minutes. By quickly cooling, the high-concentration lactose solution on the particle surface quickly crosses its glass transition temperature (Tg) to form an amorphous glassy structure, thereby enhancing the compactness and moisture resistance of the shell structure.

[0082] (5) Secondary microspray - vacuum drying to form a sealed microcapsule:

[0083] For the particles treated by low-temperature condensation enhancement, if there is slight agglomeration, appropriately depolymerize them, and then feed them into a spray drying equipment with a vacuum system (or a special vacuum spray dryer) for secondary drying. Set the process parameters: inlet air temperature 115 °C, vacuum degree in the tower maintained at 0.06 MPa. The outlet air temperature (or material temperature) is controlled at 50 - 60 °C. This step aims to further remove the residual moisture (especially the bound water), make the glassy lactose shell more stable, and finally form a highly sealed microcapsule structure.

[0084] (6)Post-treatment:

[0085] Cool the fat powder product obtained after secondary drying to room temperature in a dry environment, and then sieve it through a 100-mesh vibrating sieve to remove any possible small large particles or agglomerates. Collect the material passing through the sieve, which is the finished water-soluble fat powder for feed with high lactose and high protein content. Take samples of the product for analysis. After passing the inspection, package it in an aluminum-plastic composite bag under vacuum or nitrogen filling, and store it in a cool and dry place.

[0086] 1.3 Product performance test and results:

[0087] Conduct performance tests on the fat powder prepared in Example 1.

[0088] (a)Content of main nutritional components of the product:

[0089] Determine the crude protein content by the Kjeldahl method, the crude fat content by the Soxhlet extraction method, the lactose content by high performance anion exchange chromatography-pulsed amperometric detection (HPAEC-PAD), and the moisture content by the oven drying method.

[0090] The results are shown in Table 1 below:

[0091] ;

[0092] Note: The fat content is slightly higher than the theoretically calculated MCT content, and may contain fatty acids in a small amount of lecithin and trace fat in the raw materials. The protein content also reflects the actual conversion efficiency. The difference between the lactose content and the theoretical value may be due to analysis errors or small losses in the actual process and relative enrichment of other components.

[0093] (b)Fat entrapment rate (E):

[0094] Use the surface oil and total oil determination method. Surface oil (free fat, ) is determined by short-time shaking extraction with n-hexane or petroleum ether at room temperature. Total oil ( ) is determined by acid hydrolysis (to destroy the packaging material) followed by extraction with ether-petroleum ether.

[0095] Calculation formula:

[0096] For comparison, a control fat powder was prepared simultaneously without film condensation enhancement and secondary vacuum drying, and only using conventional single spray drying (inlet air temperature 170 °C, outlet air temperature 85 °C, wall materials are maltodextrin and sodium caseinate, lactose addition amount < 5%).

[0097] The results are shown in Table 2 below:

[0098] ;

[0099] Data shows that the fat embedding rate of the product of the present invention is significantly higher than that of the control conventional spray fat powder.

[0100] (c) Instantaneous water solubility index (SI):

[0101] Take a certain amount of sample ( , for example, 1 g) and add it to a certain volume (for example, 100 mL) of distilled water at 25 °C, and stir rapidly (such as a magnetic stirrer at 600 rpm). Stop stirring at specific time points (such as 5 seconds, 30 seconds), let it stand for a while, take the supernatant and dry it to weigh, or calculate the dissolved / dispersed amount by measuring the mass of the undissolved matter ( ).

[0102] SI is measured at 5 seconds.

[0103] Calculation formula:

[0104] In this specification, represents the instantaneous water solubility index at 5 seconds.

[0105] The results are shown in Table 3 below:

[0106] ;

[0107] The results show that the product of the present invention has excellent instantaneous water solubility. It is almost completely dissolved or forms a uniform and delicate suspension within 5 seconds.

[0108] (d) Particle size and microscopic morphology:

[0109] The particle size distribution is measured using a laser particle size analyzer (such as Malvern Mastersizer). The surface morphology of the particles is observed using a field emission scanning electron microscope (FE-SEM), and the internal sectional structure of the particles is observed using a transmission electron microscope (TEM).

[0110] The results are shown in Table 4 below and the text description:

[0111] ;

[0112] These results show that the product has a uniform particle size and a good microcapsule structure.

[0113] (e) Thermal-acid stability test:

[0114] Take a certain amount of fat powder sample, disperse it in a buffer solution with pH 4.0 (simulating the gastric acid environment), and heat it in a 90 °C water bath for 30 minutes. Measure the peroxide value (POV) of the fat before and after treatment to evaluate its stability.

[0115] The results are shown in Table 5 below:

[0116] ;

[0117] The results show that the product of the present invention can still effectively protect the internal fat under severe heat and acid conditions, with very little increase in peroxide value, showing excellent thermal-acid double stability.

[0118] (f) Lactose and protein retention rate:

[0119] By comparing the feed amount and the contents of lactose and protein in the final product and considering the total yield, the retention rate can be evaluated. In actual operation, more attention is paid to its chemical form and biological availability. The lactose content is determined by HPAEC-PAD method to ensure that it is not over-degraded. The protein content is determined by the Kjeldahl method. GPC-SEC analysis shows that a controllable and slight primary Maillard reaction bonding (such as the formation of a small amount of glycated protein) may occur between lactose and whey protein during the spray condensation stage, forming a weak covalent network, which helps to inhibit lactose crystallization and improve the emulsion stability, and has little or beneficial impact on the nutritional value. Under the process conditions of the present invention, the main chemical structures and nutritional values of lactose and protein are well retained, and the retention rates are both greater than 95%.

[0120] Example 2: Animal feeding experiment

[0121] To evaluate the effect of the water-soluble fat powder for feeding young ruminants with high lactose and high protein content prepared by the present invention (hereinafter referred to as "this product") on the growth performance of young ruminants, a 42-day feeding experiment on calves was carried out.

[0122] 2.1 Experimental design and animal grouping:

[0123] Thirty-six newly born Holstein male calves with good health conditions, similar days of age (7 ± 1 days) and body weights (40 ± 1.5 kg) were selected and randomly divided into 3 treatment groups, with 12 calves in each group, and they were fed in individual pens.

[0124] Control group (CON): Fed a basal diet (high-quality milk replacer and starter feed without extra fat powder).

[0125] Commercial fat powder group (COM): Fed a basal diet + a commercially available conventional coated fat powder (the main component is palm oil fatty acid, the embedding rate is about 70%, lactose < 5%, protein < 5%), and its addition amount makes the fat energy in the diet equivalent to that of the INV group.

[0126] INV group: Fed a basal diet + the fat powder prepared in Example 1 of the present invention, and its addition amount makes the fat energy in the diet equivalent to that of the commercial fat powder group, and at the same time provides extra lactose and protein.

[0127] The formulas (except for the fat powder) and nutritional levels of the milk replacers and starter feeds for each group were basically the same, meeting the calf feeding standards of NRC (2001). Free drinking water was provided. The experimental period was 42 days.

[0128] 2.2 Determination indexes and methods:

[0129] Average daily gain (ADG): The calves were weighed on an empty stomach at the start (d0) and end (d42) of the experiment, and the ADG was calculated.

[0130] Average daily feed intake (ADFI): The intake of milk replacer and starter feed for each calf was recorded daily.

[0131] Feed conversion ratio (FCR): FCR = ADFI / ADG.

[0132] Diarrhea rate: The fecal scores of the calves were observed daily (1 = normal formed, 2 = soft feces, 3 = loose feces, 4 = watery feces), and calves with a fecal score of 3 or 4 were recorded as having diarrhea. The percentage of the total diarrhea calf-days in each group accounting for the total observed calf-days was calculated.

[0133] 2.3 Experimental results:

[0134] The results of the feeding experiment are shown in Table 6 below:

[0135] ;

[0136] Note: The P-values and subscripts here are for illustration purposes. In actuality, ANOVA analysis and multiple comparisons (such as the Duncan or Tukey methods) should be performed using statistical software (such as SAS or SPSS).

[0137] Improved (close to 17.4%, there may be slight differences due to rounding of the average value).

[0138] Optimized (close to 11.2%).

[0139] 2.4 Result analysis and discussion:

[0140] It can be seen from the data in Table 6 that:

[0141] 1. Growth performance: The final body weight and average daily gain of the calves in the INV group were significantly higher than those in the CON group and the COM group (P < 0.01). Compared with the CON group, the average daily gain in the INV group increased by (0.97 - 0.83) / 0.83 × 100% = 16.87%. This indicates that the product of the present invention can effectively promote the growth and development of calves.

[0142] 2. Feed conversion rate: The feed conversion rate of the product group (INV) was significantly better than (i.e., lower in value) that of the control group (CON) and the commercial fat powder group (COM) (P<0.01). Compared with the control group, the feed conversion rate of the product group decreased by (1.72 - 1.53) / 1.72×100% = 11.05%. This indicates that the product can improve the utilization efficiency of nutrients in the feed.

[0143] 3. Health status: The diarrhea rate of the product group (INV) was significantly lower than that of the control group (CON) and the commercial fat powder group (COM) (P<0.05), indicating that the product has a positive effect on maintaining the intestinal health of calves.

[0144] Analyzing the reasons, the superior performance of the product of the present invention (this product) may be attributed to:

[0145] Synergistic nutrition: The high content of lactose provides easily utilizable energy for calves and may promote the early colonization of the rumen microflora and the development of the rumen epithelium. The high-quality whey protein provides a good source of amino acids, supporting the rapid growth and tissue repair of calves.

[0146] Efficient energy supply: As the fat core, MCT is itself easily digested and absorbed. Through the special coating process of the present invention, the fat is efficiently embedded and can be released in the form of fine milk droplets in the digestive tract, improving the emulsification efficiency of the fat and the action area of digestive enzymes, thus enhancing the digestion and absorption rate of the fat.

[0147] Excellent physical and chemical properties: The high water solubility of the product ensures its uniform dispersion in the milk replacer, facilitating the intake by calves; the high embedding rate and stability guarantee the quality and potency of the fat.

[0148] Possible dual-channel release mechanism: As mentioned above, the lactose-protein gradient shell may release nutrients as needed in different parts of the digestive tract: the rapid dissolution of lactose in the stomach provides immediate energy and may indirectly affect fatty acid metabolism by regulating blood sugar and insulin levels; subsequently, in the small intestine, the protein shell is gradually hydrolyzed to release the fat core, forming fine milk droplets, which is conducive to the efficient action of lipase. This orderly energy release pattern of "sugar first and then fat" may be more in line with the physiological characteristics of young animals.

[0149] In summary, through the specific ratio of lactose, protein, and fat core and the dual-phase lactose-whey protein coating-multistage spray condensation process, the present invention successfully prepared a water-soluble fat powder for animal feed with high lactose and high protein content. This product not only has a comprehensive and balanced nutrition, meeting the special needs of young animals, but also performs excellently in terms of physical and chemical properties (high encapsulation rate, instantaneous water solubility, thermal and acid stability) and biological effects (improving growth performance, improving feed conversion rate, reducing diarrhea rate). The core lies in constructing a functional lactose-protein gradient shell layer, achieving effective protection of nutrients and controllable and efficient release in the digestive tract.

[0150] The embodiments described in the present invention are only preferred solutions of the present invention and are not intended to limit the present invention. Without departing from the design concept of the present invention, any equivalent replacement or obvious improvement made by those skilled in the art to the technical solutions of the present invention shall be regarded as falling within the protection scope of the present invention. For example, the type of fat core, the source of protein, the specific selection and dosage of carrier excipients, and the adjustment of process parameters (such as temperature, pressure, time) within a certain range, as long as they can achieve the purpose and effect of the present invention, should be considered as part of the present invention.

Claims

1. A water-soluble fat powder for feed with high lactose and high protein content, characterized in that, By weight parts, the fat powder is composed of the following components: Fat core: 10 - 25 parts; Lactose: 35 - 55 parts; Protein: 20 - 35 parts; Carrier adjuvant: 5 - 15 parts.

2. The water-soluble fat powder for feeding according to claim 1, wherein The fat core is medium-chain triglyceride with a saturation degree of not less than 98%.

3. The water-soluble fat powder for feeding according to claim 1 or 2, characterized in that, The lactose is ultrafiltration desalted lactose powder with a purity of not less than 99%; and the protein is whey protein isolate by low-temperature spray drying with a protein content of not less than 90%.

4. The water-soluble fat powder for feeding according to claim 1, wherein The carrier adjuvant is selected from one or a combination of more of corn maltodextrin with a high DE value, microcrystalline cellulose, and food-grade lecithin.

5. A method for preparing a water-soluble fat powder for feeding with high lactose and high protein content as described in any one of claims 1 to 4, characterized in that, It includes the following steps: (1) Raw material pretreatment and emulsion preparation: Mix the metered fat core, lactose, protein, and carrier adjuvant with water to prepare an O / W type emulsion containing the fat core, lactose, and protein; (2) Low-temperature homogenization and emulsification: Subject the emulsion obtained in step (1) to high-pressure homogenization treatment at 20 - 30 MPa under the condition of 5 - 15 °C for 1 - 3 cycles; (3) Primary spray granulation to form a primary shell layer: Conduct the first spray drying on the homogenized emulsion obtained in step (2), with an inlet air temperature of 130 - 160 °C and an outlet air temperature of 60 - 75 °C to obtain primary coated particles; (4) Film condensation strengthening and lactose vitrification: Conduct low-temperature treatment on the primary coated particles obtained in step (3) at -25 °C to -15 °C for 30 - 60 minutes to cause vitrification transformation of the lactose on the surface layer or near the surface layer of the particles; (5) Secondary microspray - vacuum drying to form a sealed microcapsule: Conduct secondary spray drying or vacuum drying on the particles treated in step (4), where the inlet air temperature for secondary spray drying is 100 - 125 °C, or conduct drying under a vacuum condition of 0.04 - 0.08 MPa.

6. The method according to claim 5, wherein In the emulsion preparation of step (1), the dry matter mass ratio of lactose, whey protein, and fat core is (2.5 - 3.5):(1.5 - 2.5):

1.

7. The method according to claim 5 or 6, characterized in that, The low-temperature homogenization and emulsification in step (2) are preferably carried out at 8 - 12 °C and 25 MPa pressure for 2 cycles.

8. The method according to any one of claims 5 to 7, characterized in that The film condensation strengthening in step (4) is preferably carried out at -20 °C for 45 minutes; the secondary microspray - vacuum drying in step (5) preferably adopts the conditions of an inlet air temperature of 115 °C and a vacuum degree of 0.06 MPa.