Chicken plasma protein powder, spray drying optimization process and application thereof

Abstract

The application discloses chicken plasma protein powder and a spray drying optimization process and application thereof. Response surface method is adopted to perform systematic optimization on three key parameters of spray drying for the first time, a high-precision prediction model is established, and the best process combination is determined as follows: a feeding rate of 312 mL / h, an inlet temperature of 196 DEG C and an atomization pressure of 0.20 MPa. The process effectively reduces protein denaturation while simplifying the process, and the obtained chicken plasma protein powder has a crude protein retention rate of 56.97%. Multidimensional evaluation of physical and chemical indexes, protein nutrition indexes and safety indexes shows that: the mineral content is sufficient; the amino acid pattern score is excellent, and is much higher than the FAO / WHO reference value; and the functional protein content is rich. The total number of bacteria and mold colonies and the detection amount of heavy metals all meet the feed hygiene standards. The protein powder can meet the growth needs of animals and meet the high-quality feed protein standard. The application provides a reliable technical scheme for efficient utilization of chicken blood resources.

Description

Technical Field

[0001] This invention belongs to the field of deep processing of livestock and poultry by-products and protein feed technology. Specifically, it relates to a method for preparing chicken plasma protein powder based on response surface methodology to optimize spray drying process, as well as a systematic evaluation of its quality characteristics and its application in the preparation of feed or feed additives. Background Technology

[0002] Blood is one of the main byproducts of livestock and poultry processing. It is rich in protein, various essential amino acids, and bioactive substances, and has high processing and utilization value. However, at present, a large amount of blood is directly discarded or simply treated, which not only causes a huge waste of protein resources, but its high nitrogen and high phosphorus characteristics also pose a serious pollution pressure on the aquatic environment.

[0003] Spray drying technology, characterized by its instantaneous drying capability, effectively preserves the activity of heat-sensitive materials, making it the preferred process for preparing chicken plasma protein powder. However, existing technologies suffer from drawbacks such as high costs due to complex routes or difficulty in scaling up due to rudimentary processes, significantly hindering their industrial application and product quality improvement. For example, the method for preparing pig plasma protein powder disclosed in patent CN102132760B requires multiple processes such as ultrafiltration concentration, physical deoxygenation, and activated carbon decolorization to obtain a low-ash product. While this improves product purity, the long process flow, large equipment investment, and high energy consumption significantly increase production costs, limiting its large-scale application in the cost-sensitive feed industry. Patent CN201610316993 utilizes pig blood to develop food-grade plasma protein powder products, adding steps such as membrane concentration and irradiation sterilization to ensure product safety. This leads to an increase in overall process complexity and production costs. Although it achieves the specific goals of high purity and high safety, it fails to meet the core needs of the feed industry for economical and large-scale production of protein raw materials. In the literature (Li Weifeng et al. Optimization of spray-dried chicken plasma protein powder process [J]. Transactions of the Chinese Society of Agricultural Engineering, 2012), the process optimization only selected two factors, inlet temperature and feed rate, and set the atomization pressure to a fixed value. The optimal process parameter combination obtained was 150℃ and 0.17mL / s (approximately 601.20 mL / h), which belongs to a typical "low temperature-high speed" mode. The limitation of this optimization method is that it fails to comprehensively examine the interaction law of multiple factors such as feed rate, inlet temperature, and atomization pressure. The predictive and guiding ability of the constructed model is limited, resulting in a narrow process window. When scaled up production, it is easy to cause problems such as product quality fluctuations and unstable yields, making it difficult to provide accurate and effective guidance for industrial production.

[0004] Meanwhile, existing technologies for evaluating the quality of plasma protein powder are mostly limited to detecting crude protein mass fraction, lacking a systematic evaluation of key indicators such as protein amino acid composition, nitrogen solubility index, immunoglobulins, and mineral content. This makes it difficult to comprehensively reflect the actual nutritional value of the product, hindering its widespread application in the feed protein field. Fishmeal, as the most widely used animal-derived protein feed, not only faces the challenges of continuously rising costs and unstable market supply, but also quality risks such as histamine deterioration, raw material adulteration, and large fluctuations in salt content. Soy protein powder, as an economical plant protein source feed, contains anti-nutritional factors, has limited methionine and lysine content, and lacks some essential amino acids, making it only suitable for feeding situations with lower requirements for amino acid balance.

[0005] Based on the above situation, in order to improve the utilization rate and economic value of chicken blood resources, it is urgent to develop an optimized spray drying process for chicken blood that is low-cost, refined, and highly nutritious, and to conduct a systematic and comprehensive quality evaluation of the product; in order to solve the defects of the existing process, meet the feed industry's demand for high-quality plasma protein powder, and promote the upgrading of the utilization of by-product chicken blood resources. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing spray drying processes for preparing chicken plasma protein powder, such as complex processes, unstable product quality, and imperfect evaluation systems. By systematically optimizing the spray drying process using response surface methodology, this invention achieves, for the first time, precise quantification of parameters such as feed rate, inlet temperature, and atomization pressure, and their interaction effects, obtaining optimal process parameters for stable production of high-quality products. Simultaneously, a systematic and comprehensive quality evaluation of the chicken plasma protein powder is conducted, breaking through the limitations of previous methods that only focused on crude protein content, and systematically examining key indicators such as amino acid composition, nitrogen solubility index, and immunoglobulin content. This results in a feed-grade, safe chicken plasma protein powder with high yield, high crude protein retention, high nutritional value, and high solubility, achieving efficient preparation of high-quality chicken plasma protein powder to alleviate the shortage of animal-derived protein feed, meet the feed industry's demand for high-quality protein raw materials, and promote technological upgrading in related industries.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, this invention provides an optimized spray drying process for chicken plasma protein powder. The core innovation of this process lies in the systematic optimization of the core process parameters of spray drying using response surface methodology. With the crude plasma protein retention rate as the key response indicator, the optimal combination and interaction law of three key process parameters—feed rate (A), inlet temperature (B), and atomization pressure (C)—were determined.

[0008] Secondly, the present invention provides a chicken plasma protein powder product, which is prepared by the above-mentioned optimized process.

[0009] Thirdly, this invention evaluates the quality of chicken plasma protein powder by detecting and evaluating at least the following three categories of indicators: Physicochemical indicators: plasma crude protein retention rate, plasma protein powder yield, crude protein mass fraction, moisture content, crude fat content, crude ash content, and mineral element content (sodium, potassium, magnesium, calcium, chlorine, iron, copper, zinc, manganese). Protein nutritional indicators: nitrogen solubility index (NSI), total amino acid content, essential amino acid composition, amino acid pattern, and content of functional proteins (albumin, IgY, IgM, IgA); Safety indicators: total bacterial count, total mold count, and detection levels of heavy metals (cadmium, chromium, mercury, lead, arsenic).

[0010] An optimized spray drying process for chicken plasma protein powder employs response surface methodology to systematically optimize the core process parameters of spray drying. The specific steps include: (1) Take fresh chicken whole blood, add anticoagulant, centrifuge and separate to obtain plasma, store at -80℃; (2) Thaw the plasma obtained in step (1) and filter it to obtain plasma filtrate; (3) Based on the single-factor experiment, with the crude protein retention rate of plasma as the response value, the three core influencing factors of the drying process, namely feed rate, inlet temperature and atomization pressure, were selected and response surface experiments were conducted using Box-Behnken design. (4) Based on the response surface experimental data, the results were fitted by multiple regression to establish a quadratic polynomial regression model of plasma crude protein retention rate and the three key process parameters. (5) Determine the optimal combination of process parameters based on the model, and spray dry the plasma filtrate under these parameters to obtain plasma protein powder.

[0011] Specifically, the response surface quadratic polynomial regression model is as follows: Y = 56.44 + 1.16A - 0.8087B + 0.1838C - 2.71AB - 4.75AC - 3.66BC -6.07A 2 - 3.39B 2 - 3.84C 2 , Where Y is the crude protein retention rate of plasma, A is the feed rate, B is the inlet temperature, and C is the atomization pressure.

[0012] Specifically, the model's coefficient of determination R 2 The value is 0.9875, the model term is <0.0001, and the misfit term is 0.1017.

[0013] Specifically, the optimized process parameters are: feed rate 200 mL / h ~ 600 mL / h, inlet temperature 180℃ ~ 260℃, and atomization pressure 0.10 MPa ~ 0.50 MPa.

[0014] The optimal process parameters determined by the model are: feed rate 312 mL / h, inlet temperature 196℃, and atomization pressure 0.20 MPa.

[0015] Preferably, in step (1), the anticoagulant is sodium citrate, and its final mass fraction in chicken whole blood is 1%.

[0016] Preferably, the chicken plasma protein powder is a light yellow powder with a uniform texture, free of visible impurities and lumps; the crude protein retention rate is 56.97%, the chicken plasma protein powder yield is 6.53%, the crude protein content is 70.18%, the moisture content is 7.91%, the crude fat content is 0.58%, and the crude ash content is 12.19%. The main mineral elements are sodium (6931.50 mg / kg), potassium (12753.50 mg / kg), magnesium (8642.50 mg / kg), calcium (3929.50 mg / kg), chlorine (24234.00 mg / kg), and iron (165.89 mg / kg). The nitrogen solubility index (NSI) was 83.64%, and the total amino acid content reached 647.21 mg / g, of which the essential amino acid content was 347.62 mg / g. The proportion of essential amino acids to total amino acids (EAA / TAA) was 53.71%, indicating an ideal amino acid pattern, all significantly exceeding the WHO / FAO recommended range, classifying it as a high-quality protein. It was rich in functional proteins, with albumin content of 311.47 mg / g, immunoglobulin Y (IgY) content as high as 93.57 mg / g, immunoglobulin M (IgM) content of 22.88 mg / g, and immunoglobulin A (IgA) content of 12.54 mg / g. The total bacterial count was 3.30 × 10⁻⁶. 5 CFU / g, total mold count was 9.50 × 10⁻⁶ 3 CFU / g; heavy metals lead and mercury were not detected, cadmium was detected at 0.03 mg / kg, chromium at 2.27 mg / kg, and arsenic at 1.12 mg / kg, all of which are far below the limits of GB13078-2017 "Feed Hygiene Standard".

[0017] The present invention also provides the application of the chicken plasma protein powder in the preparation of feed or feed additives.

[0018] Specifically, this invention refers to Figure 1The technical process is carried out. Specifically, it includes the following steps: Step 1 Raw material pretreatment Collect fresh whole blood from slaughtered chickens, ensuring the raw material is free from spoilage and contamination. Add sodium citrate, an anticoagulant, to the fresh whole blood, bringing its final mass fraction to 1%, and stir thoroughly to prevent blood clotting. Centrifuge at 3000 r / min for 20 min at 4℃. After centrifugation, collect the supernatant plasma and immediately freeze it at -80℃ to prevent protein denaturation. Before use, thaw the frozen plasma, filter to remove impurities, and obtain clear plasma for later use.

[0019] Step 2: Single-factor experiment on spray drying process The drying process, using a spray dryer, is the core step in the preparation of plasma protein powder. The feed rate is controlled at 200 mL / h to 600 mL / h; the inlet temperature is set at 180℃ to 260℃; the atomization pressure is adjusted to 0.10 MPa to 0.50 MPa; and the outlet temperature is dynamically controlled within the range of 52℃ to 84℃, varying with the above process parameters. After spray drying, the product is cooled to room temperature, and the finished plasma protein powder is collected. The crude plasma protein retention rate is then calculated.

[0020] Step 3: Optimization of spray drying process conditions and interaction analysis using response surface methodology. Based on single-factor data, the parameter range for response surface optimization was determined, with the feed rate controlled at 200 mL / h ~ 400 mL / h; the inlet temperature set at 180℃ ~ 220℃; and the atomization pressure adjusted to 0.10 MPa ~ 0.30 MPa. Figure 2 As shown.

[0021] Using plasma crude protein retention rate (Y) as the response value, a Box-Behnken response surface methodology was designed, selecting three key factors: feed rate (A), inlet temperature (B), and atomization pressure (C). A quadratic polynomial regression model was obtained by fitting the plasma crude protein retention rate (Y) results to multiple regression. Y = 56.44 + 1.16A - 0.8087B + 0.1838C - 2.71AB - 4.75AC - 3.66BC -6.07A 2 - 3.39B 2 - 3.84C 2 Note: ** indicates extremely significant difference, P < 0.01; * indicates significant difference, P < 0.05 The analysis of variance for this model, as shown in Table 1, reveals that the model terms are highly significant (P < 0.0001), while the lack-of-fit terms are not significant (P = 0.1017), indicating a good model fit and a true reflection of the relationship between factors and response values. The model's coefficient of determination, R0, is also shown. 2 The corrected coefficient of determination R is 0.9875. 2 Adj The coefficient of variation (CV) was 0.9715, and the coefficient of variation (CV = 1.86%) was low, demonstrating the high reliability and accuracy of the model. The order of influence of each factor on the crude protein retention rate of plasma was: feed rate (A) > inlet temperature (B) > atomization pressure (C). Among them, the linear terms A and B, the interaction terms AB, AC, and BC, and all quadratic terms had extremely significant effects on the response value (P < 0.01). Response surface 3D plot and contour plot ( Figure 3 It intuitively demonstrates the interaction between various factors.

[0022] like Figure 3 As shown in Figure A, the AB response surface is steep, indicating a significant interaction between the feed rate and the inlet temperature. Furthermore, the slope change is more pronounced along the feed rate direction, suggesting that it has a greater impact on the crude plasma protein retention rate than the inlet temperature. Regardless of whether the feed rate or the inlet temperature is fixed, the crude plasma protein retention rate initially increases and then decreases with increasing levels of the other factor.

[0023] like Figure 3 As shown in Figure C, the AC response surface is steep, indicating a significant interaction between feed rate and atomization pressure. The slope of the response surface corresponding to feed rate changes even more significantly, further demonstrating that feed rate has a greater impact on crude protein retention than atomization pressure. Regardless of whether the feed rate or atomization pressure is fixed, the plasma crude protein retention rate initially increases and then decreases with the increase of the other factor.

[0024] like Figure 3 As shown in E, the BC response surface is steep, and the interaction between inlet temperature and atomization pressure is also significant. With a fixed inlet temperature, the crude protein retention rate first increases and then decreases with increasing atomization pressure; with a fixed atomization pressure, the crude protein retention rate shows a similar trend with increasing inlet temperature. The slope in the inlet temperature direction is steeper than that in the atomization pressure direction, indicating that it has a greater impact on the crude protein retention rate.

[0025] Contour maps corresponding to the three sets of surfaces AB, AC, and BC ( Figure 3 B, 3D, and 3F show distinct elliptical shapes, further confirming that the three sets of interactions (feed rate-inlet temperature, feed rate-atomization pressure, and inlet temperature-atomization pressure) all have a significant impact on the crude protein retention rate of plasma.

[0026] The combined response surface 3D plot and contour plot show that the order of influence of the three factors on crude protein retention rate is: feed rate > inlet temperature > atomization pressure. This result is highly consistent with the conclusion of the regression model variance analysis.

[0027] Through model optimization, the optimal theoretical parameters for spray drying were determined to be: feed rate 312.35 mL / h, inlet temperature 196.23℃, and atomization pressure 0.20 MPa, with a predicted plasma crude protein retention rate of 56.59%. For ease of practical operation, the parameters were modified to: feed rate 312 mL / h, inlet temperature 196℃, and atomization pressure 0.20 MPa, and verification experiments were conducted.

[0028] The validation results showed that the crude protein retention rate of the plasma was 56.97%, with a relative error of only 0.66% (<5%) compared to the model prediction. Furthermore, the product was in good condition with minimal wall adhesion. These results fully validated the effectiveness and reliability of the response surface methodology, demonstrating that the established optimized process conditions are accurate and feasible, and can be used in the actual production of chicken plasma protein powder.

[0029] Step 4: Evaluation of Physicochemical Indicators The chicken plasma protein powder produced by the above optimized process is shown in the image. Figure 5 The finished product is a light yellow powder with a uniform texture and no obvious oxidative odor or clumping. The plasma crude protein retention rate was 56.97%, the plasma protein powder yield was 6.53%, the crude protein mass fraction was 70.18%, the water content was 7.91%, the crude fat content was 0.58%, and the crude ash content was 12.19%.

[0030] The mineral element analysis results of chicken plasma protein powder are shown in Table 2, revealing its significant electrolyte enrichment characteristics. Regarding macroelements, the product is rich in sodium (6931.50 mg / kg), potassium (12753.50 mg / kg), magnesium (8642.50 mg / kg), and calcium (3929.50 mg / kg). Particularly noteworthy is its extremely high chloride content, reaching 24234.00 mg / kg, which is highly consistent with the natural physiological function of plasma as extracellular fluid in maintaining osmotic pressure. Furthermore, the sodium, potassium, calcium, and chloride contents are all higher than those of 14 commercially available feed-grade livestock and poultry plasma protein powders studied in the literature (Wang Wenting et al. Quality Analysis and Comparison of Plasma Protein Powder Products [J]. Food Science and Technology, 2017). Therefore, this product has unique advantages in weaning diets for young livestock or starter feeds for aquatic animals. It not only provides high-quality protein but also effectively maintains intestinal osmotic pressure and replenishes electrolytes during stress periods, thereby alleviating diarrhea and dehydration caused by weaning or environmental changes. In addition, the presence of calcium and magnesium also supports bone development and neuromuscular function.

[0031] Regarding trace elements, essential trace elements such as iron (165.89 mg / kg), zinc (29.67 mg / kg), copper (7.14 mg / kg), and manganese (6.16 mg / kg) were at appropriate physiological levels. Among them, the higher iron content plays a positive role in replenishing blood and preventing anemia in piglets; zinc and copper help maintain intestinal barrier function, promote growth, and enhance immunity; manganese helps with bone development and the function of antioxidant enzyme systems, further ensuring metabolic homeostasis and structural health of young animals during their rapid growth period.

[0032] Compared with the recommended values ​​of blood meal in the Chinese Feed Composition and Nutritional Value Table (Chinese Feed [J], 2024), the mineral content of this chicken plasma protein powder is higher, and there is no biosafety risk of the spread of viruses such as porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus (PCV) caused by the use of homologous plasma powder. Therefore, it is an ideal alternative to porcine plasma protein powder.

[0033] Table 2. Mineral content of chicken plasma protein powder based on ICP-MS method Note: The recommended values ​​for pig blood meal are from the "Table of Chinese Feed Composition and Nutritional Value (35th Edition, 2024)".

[0034] Step 5: Protein Nutritional Assessment A higher nitrogen solubility index indicates stronger solubility and stability of the protein in water. The nitrogen solubility index (NSI) of this chicken plasma protein powder was measured to be 83.64%, which indicates that the protein molecular structure did not undergo severe denaturation under the optimized spray drying process, and maintained good hydration capacity and dispersion stability.

[0035] The amino acid analysis results of the plasma protein powder obtained by the above optimized process using acid hydrolysis and alkaline hydrolysis (tryptophan) are shown in Table 3. The essential amino acid content of this chicken plasma protein powder was scored using the ideal protein essential amino acid content proposed by FAO / WHO as the standard; the ratio of essential amino acids to total amino acids (EAA / TAA) and the ratio of essential amino acids to non-essential amino acids (EAA / NAA) were calculated and compared with the ideal amino acid pattern of FAO / WHO. The chicken plasma protein powder contains a complete range of amino acids, including the 18 common amino acids, with a total content of 647.21 mg / g. Among the essential amino acids, leucine (72.35 mg / g), lysine (59.19 mg / g), and valine (48.35 mg / g) were relatively high; among the non-essential amino acids, glutamic acid (66.23 mg / g), alanine (59.35 mg / g), and aspartic acid (58.00 mg / g) were the main components.

[0036] The nutritional value of protein depends primarily on the types, quantities, and proportions of essential amino acids it contains. This chicken plasma protein powder contains a complete range of essential amino acids, with a total content of 347.62 mg / g, exceeding the FAO / WHO recommended reference value (278 mg / g), making it a high-quality protein source with ample essential amino acids. Lysine is typically the first limiting amino acid in grain feeds, and this chicken plasma protein powder is rich in lysine, so it can be used as a feed additive in combination with grain feeds to enhance the protein nutritional value of the mixed feed. Furthermore, the EAA / TAA ratio of this chicken plasma protein powder is 53.71%, better than the FAO / WHO recommended reference value (40%), and the EAA / NAA ratio is 116.03%, also better than the FAO / WHO recommended reference value (60%). This indicates that this chicken plasma protein powder can effectively meet the growth needs of animals, especially showing significant value for the intestinal health, muscle growth, and metabolic balance of young animals, making it an excellent protein source.

[0037] The average amino acid score of this chicken plasma protein powder is 130.51%, indicating its great potential as a high-quality protein in animal feed. Although its methionine + cysteine ​​content is low, its final nutritional value can be improved by compounding it with other feed proteins such as feather protein powder through the principle of protein complementarity.

[0038] Table 3. Amino acid content, FAO / WHO pattern analysis, and essential amino acid score in chicken blood cell powder. Note: "*" indicates an essential amino acid.

[0039] The albumin content in this chicken plasma protein powder was determined by enzyme-linked immunosorbent assay (ELISA) to be 311.47 mg / g; the immunoglobulin IgY content was 93.57 mg / g, the IgM content was 22.88 mg / g, and the IgA content was 12.54 mg / g. The SDS-PAGE electrophoresis image is shown below. Figure 4 As shown: the IgM heavy chain (80 kDa) is located at the top, albumin (66 kDa) and IgY heavy chain (67 kDa) are located around 70 kDa, the IgA heavy chain (60 kDa) is located below it, and the light chain (22–25 kDa) common to all immunoglobulins appears in the region below 35 kDa.

[0040] Albumin is the most abundant protein in chicken plasma. Its key difference from ordinary proteins lies in its role as not only a source of amino acids but also a crucial physiological regulator. Albumin contributes approximately 75%–80% of the colloid osmotic pressure in plasma, maintaining fluid balance. It also binds and transports fatty acids, metal ions, and other substances, thus buffering blood pH and aiding in detoxification. For young animals prone to stress and dehydration, such as weaned piglets, albumin's physiological regulatory role is particularly important, providing vital physiological support during the immune window. IgY, the most abundant immunoglobulin in chicken plasma, effectively neutralizes viruses and agglutinates antigens, directly participating in immune defense in the intestines. Its good stability allows it to be used as an oral medication or feed additive to prevent early gastrointestinal diseases. IgA strengthens the intestinal mucosal immune barrier, which is especially significant for preventing diarrhea in weaned piglets. IgM rapidly initiates an immune response, exerting strong agglutination and lysis effects to eliminate pathogens. The synergistic effect of these three immunoglobulins constructs a multi-layered immune defense from the intestinal tract to the whole body, reducing antibiotic use and improving the survival rate and growth performance of young animals.

[0041] Step 6 Safety Indicator Evaluation As shown in Table 4, due to the high-temperature treatment, the total bacterial count and total mold count in the chicken plasma protein powder meet the requirements of GB 13078-2017 "Feed Hygiene Standard"; the levels of heavy metals cadmium, chromium, and arsenic are lower than the national standard limits, and mercury and lead are not detected, indicating that its production process is standardized, the raw materials are pure, and there is no obvious risk of environmental pollution or heavy metal enrichment.

[0042] Table 4 Safety Indicators and National Standard Limits Note: The national standard limit data is from GB 13078-2017 "Feed Hygiene Standard"; ND represents not detected.

[0043] The above results show that, using the optimized process parameters provided by this invention, high-quality chicken plasma protein powder with rich protein and mineral content, good solubility, ideal amino acid composition, and microbial heavy metal indicators meeting safety requirements has been successfully prepared, making it an ideal animal protein feed ingredient.

[0044] In this invention, the calculation formulas for each quality evaluation index are as follows: Plasma protein powder yield (%) = ×100% ×100% Nitrogen Solubility Index (NSI) ×100% In the above formula: Ms----Mass of plasma protein powder collected after spray drying (g) Ps----Crude protein content (%) of plasma protein powder Mo----Plasma sample mass (g) Po----Crude protein content (%) of plasma sample Mw----The mass (g) of the plasma protein powder collected after spray drying and dissolved in water. Pw----Crude protein content (%) of plasma protein powder aqueous solution The beneficial effects of this patent application are: 1. For the first time, a systematic single-factor and response surface methodology study was conducted on the spray drying process of chicken plasma protein powder. The optimal combination and interaction mechanism of three key parameters—feed rate, inlet temperature, and atomization pressure—were clarified. The constructed model demonstrated high predictive accuracy, and stable and reliable process parameters were obtained through validation. Based on this, a spray drying process with high yield, high crude protein retention, and high nutritional value was developed. This process employs a unique parameter combination of "higher inlet temperature (196℃) combined with a lower feed rate (312 mL / h)," which differs from the "low temperature-high speed" (e.g., 150℃, 601.2 mL / h) mode used in existing literature. Its innovative mechanism lies in extending the residence time of droplets in the drying tower by reducing the feed rate. This results in a more moderate actual heating of the material at an inlet temperature of 196℃ (outlet temperature approximately 63-64℃), thereby minimizing protein thermal denaturation while ensuring drying efficiency. This process effectively avoids problems such as easy sticking and scorching caused by traditional high temperatures, or insufficient drying caused by excessively low temperatures. It offers better process stability and repeatability, significantly improving the product's basic physicochemical and protein nutritional indicators (such as high plasma protein powder yield, high crude protein retention, high protein mass fraction, and high NSI). A systematic and comprehensive protein quality evaluation confirmed that this process effectively preserves the nutritional value of protein. This study aims to overcome the shortcomings of existing processes, and the resulting high-quality chicken plasma protein powder can meet the needs of the feed industry, promote the upgrading of livestock and poultry blood resource utilization, and alleviate the environmental pollution problems it causes.

[0045] 2. The chicken plasma protein powder prepared by this invention has an excellent nitrogen solubility index (NSI of 83.64%). A high NSI indicates that the protein powder underwent a mild drying process (spray drying) during production, avoiding excessive heat treatment; reducing protein denaturation, aggregation, and damage to heat-sensitive amino acids (such as lysine). Furthermore, the protein exhibits strong solubility, stability, and dispersibility in water, indicating that the amino acid / peptide mixture formed after digestion can be more quickly absorbed into the bloodstream by the small intestine; it is not only easily digested and absorbed by animals but also effectively retains bioactive components such as immunoglobulins and growth factors, enhancing the immunity of fed animals. These characteristics collectively demonstrate that chicken plasma protein powder can rapidly provide an absorbable nitrogen source; it has significant advantages in supporting animal growth, reducing metabolic burden, and increasing animal appetite, and is particularly suitable for feed for young animals with underdeveloped digestive systems.

[0046] 3. The plasma protein powder prepared by this invention has an excellent amino acid profile, with an essential amino acid ratio (EAA / TAA = 53.71%) superior to the FAO / WHO ideal protein profile (40%). It is particularly rich in leucine (72.35 mg / g) and lysine (59.19 mg / g), and contains almost no crude fiber, making it easily digestible and absorbable, effectively reducing the digestive burden on animals. Compared to fishmeal, chicken plasma protein powder exhibits potential for substitution and complementarity in several aspects. While fishmeal is a traditional high-quality protein source due to its balanced amino acid profile, rich content of unknown growth factors and ω-3 fatty acids, its resources are becoming increasingly scarce, its price is high, and it suffers from problems such as high salt content and susceptibility to contamination and spoilage. In contrast, the chicken plasma protein powder prepared in this invention has a crude protein content of 70.18%, higher than imported fishmeal (approximately 64%), and contains immunoglobulins IgY, IgM, IgA, and albumin, which are not found in fishmeal, thus helping to enhance animal immunity (Lü Yongbiao et al. Research progress on the immunonutritional effects and applications of spray-dried chicken plasma protein powder [J]. Foreign Animal Husbandry, 2016). Furthermore, although plant-based protein feeds such as soybeans are lower in cost, they have several limitations, including limited lysine content, deficiency of essential amino acids such as methionine and tryptophan, and the presence of anti-nutritional factors, making their nutritional value inferior to chicken plasma protein powder. Therefore, combining chicken plasma protein powder with plant proteins such as soybeans, or partially replacing expensive fishmeal, can effectively compensate for the amino acid deficiencies in plant-based feeds, optimize the overall amino acid balance of feed formulations, and thus improve the growth performance and health of farmed animals. This has significant resource utilization value and application prospects. Attached Figure Description

[0047] Figure 1 Schematic diagram of the spray drying process for chicken plasma protein powder Figure 2 Effects of different feed rates, inlet temperatures, and atomization pressures on crude protein retention in chicken plasma Figure 3 Response surface and contour plot of the effects of the interaction of various factors on the crude protein retention rate of chicken plasma Figure 4 SDS-PAGE electrophoresis image of chicken plasma protein powder Figure 5 Chicken plasma protein powder finished product image Detailed Implementation The present invention will be further described below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0048] Example 1: Preparation of broiler chicken plasma protein powder (1) Raw material pretreatment: Fresh whole blood from 39-day-old healthy white-feathered chickens raised in Luanfeng Township, Guangze County, Fujian Province, was immediately added with a 10% sodium citrate solution for anticoagulation, ensuring that the final sodium citrate concentration in the blood sample reached 1%. After the anticoagulated whole blood was thoroughly mixed, it was centrifuged at 3000 r / min for 20 min at 4°C to obtain the supernatant plasma, which was then frozen and stored at -80°C for later use.

[0049] (2) Plasma pretreatment: The frozen plasma is thawed at room temperature and then slowly poured into a double layer of sterile gauze for filtration to remove any trace amounts of blood cell clots, fibrin, and tissue debris that may remain. The clear plasma filtrate is then collected.

[0050] (3) Spray drying: The plasma filtrate was dried using a JOYN-8000T spray dryer. The obtained plasma filtrate was spray-dried under the following optimized process parameters: feed rate 312 mL / h, inlet temperature 196℃, atomization pressure 0.20 MPa. Under these conditions, the outlet temperature remained stable at 63-64℃. After drying, the product was cooled to room temperature, and the powder collected from the drying tower and cyclone separator was obtained as the finished broiler chicken plasma protein powder.

[0051] (4) Product evaluation: The obtained plasma protein powder was tested, and the results are as follows: the product is a light yellow powder with a uniform texture; there is no clumping or scorching, slight adhesion to the walls, and no putrid or spoiled odor. Physicochemical and protein nutritional indicators: the crude plasma protein retention rate is 56.97%, the plasma protein powder yield is 6.53%, the crude protein mass fraction is 70.18%, the water content is 7.91%, the crude fat content is 0.58%, and the crude ash content is 12.19%. It is rich in minerals, mainly including sodium (6931.50 mg / kg), potassium (12753.50 mg / kg), magnesium (8642.50 mg / kg), calcium (3929.50 mg / kg), chlorine (24234.00 mg / kg), and iron (165.89 mg / kg).

[0052] The protein nutrition evaluation of this product is as follows: The nitrogen solubility index (NSI) reaches 83.64%, containing 18 common amino acids with a total content of 647.21 mg / g. The essential amino acid content is 347.62 mg / g, exceeding the FAO / WHO recommended standard (278 mg / g). Among the essential amino acids, leucine has the highest content (72.35 mg / g), followed by lysine (59.19 mg / g). Furthermore, the EAA / TAA ratio of this chicken plasma protein powder is 53.71%, better than the FAO / WHO recommended protein model reference value (40%), and the EAA / NAA ratio is 116.03%, also better than the FAO / WHO recommended protein model reference value (60%). Based on the FAO / WHO ideal protein essential amino acid model, the results indicate that this product has an excellent amino acid profile and sufficient nutritional value, effectively meeting the growth needs of animals, especially beneficial for the intestinal health, muscle growth, and metabolic balance of young animals.

[0053] The functional protein content in chicken plasma protein powder is as follows: albumin is 311.47 mg / g, IgY is as high as 93.57 mg / g, IgM is 22.88 mg / g, and IgA is 12.54 mg / g; this product is especially suitable for weaned young animals whose immune systems are not yet fully developed.

[0054] Safety indicator: Total bacterial count 3.30 × 10⁻⁶ 5 CFU / g, total mold count was 9.50 × 10⁻⁶ 3 CFU / g; heavy metals mercury and lead were not detected, cadmium was detected at 0.03 mg / kg, chromium at 2.27 mg / kg, and arsenic at 1.12 mg / kg, all of which comply with GB13078-2017 "Feed Hygiene Standard".

[0055] (5) In order to demonstrate the advantages of the optimized parameters of the present invention, different process conditions were set for comparison.

[0056] Comparative Example 1: Feed rate 500 mL / h, inlet temperature 220℃ and atomization pressure 0.20 MPa, other parameters were the same as in Example 1. The results showed severe product adhesion to the walls, a moisture content of 8.21%, and a significant decrease in yield and crude protein retention to 3.88% and 33.06%, respectively.

[0057] Comparative Example 2: Inlet temperature 240℃, feed rate 300 mL / h, and atomization pressure 0.20 MPa, other parameters were the same as in Example 1. The results showed more wall adhesion and slight scorching, with the yield and crude protein retention rate significantly decreasing to 4.34% and 34.89%, respectively.

[0058] Comparative Example 3: Atomization pressure 0.4 MPa, feed rate 300 mL / h, and inlet temperature 200℃, other conditions were the same as in Example 1. The results showed that the product adhered significantly to the walls, had a moisture content of 9.46%, and the yield and crude protein retention rate decreased significantly to 5.22% and 45.15%, respectively.

[0059] The above comparison clearly shows that deviations from the optimized process parameters determined by this invention (feed rate 312 mL / h, inlet temperature 196℃, atomization pressure 0.20 MPa) will lead to a decrease in chicken plasma protein powder yield and crude protein retention rate, resulting in quality deterioration, thus confirming the scientific nature of the technical solution of this invention.

Claims

1. An optimized spray drying process for chicken plasma protein powder, characterized in that, The core process parameters of spray drying were systematically optimized using response surface methodology, specifically including the following steps: (1) Take fresh chicken whole blood, add anticoagulant, centrifuge and separate to obtain plasma, store at -80℃; (2) Thaw the plasma obtained in step (1) and filter it to obtain plasma filtrate; (3) Based on the single-factor experiment, with the crude protein retention rate of plasma as the response value, the three core influencing factors of the drying process, namely feed rate, inlet temperature and atomization pressure, were selected and response surface experiments were conducted using Box-Behnken design. (4) Based on the response surface experimental data, the results were fitted by multiple regression to establish a quadratic polynomial regression model of plasma crude protein retention rate and the three key process parameters. (5) Determine the optimal combination of process parameters based on the model, and spray dry the plasma filtrate under these parameters to obtain plasma protein powder.

2. The optimized spray drying process according to claim 1, characterized in that, The response surface quadratic polynomial regression model is as follows: Y = 56.44 + 1.16A - 0.8087B + 0.1838C - 2.71AB - 4.75AC - 3.66BC - 6.07A 2 - 3.39B 2 - 3.84C 2 , Where Y is the crude protein retention rate of plasma, A is the feed rate, B is the inlet temperature, and C is the atomization pressure.

3. The optimized spray drying process for chicken plasma protein powder according to claim 2, characterized in that, The model's coefficient of determination R 2 The value is 0.9875, the model term is <0.0001, and the misfit term is 0.1017.

4. The optimized spray drying process according to any one of claims 1 to 3, characterized in that, Optimized process parameters range: feed rate 200 mL / h ~ 600 mL / h, inlet temperature 180℃ ~ 260℃, atomization pressure 0.10 MPa ~ 0.50 MPa.

5. The optimized spray drying process according to claim 4, characterized in that, The optimal process parameters determined by the model are: feed rate 312 mL / h, inlet temperature 196℃, and atomization pressure 0.20 MPa.

6. The optimized spray drying process according to claim 1, characterized in that, In step (1), the anticoagulant is sodium citrate, and its final mass fraction in chicken whole blood is 1%.

7. A chicken plasma protein powder, characterized in that, It is prepared by the optimized spray drying process according to any one of claims 1 to 6.

8. The chicken plasma protein powder according to claim 7, characterized in that, The finished product is a light yellow powder with a uniform texture, free of visible impurities and lumps; the crude protein retention rate of plasma is 56.97%, the yield of chicken plasma protein powder is 6.53%, the crude protein content is 70.18%, the moisture content is 7.91%, the crude fat content is 0.58%, and the crude ash content is 12.19%. The main mineral elements are sodium (6931.50 mg / kg), potassium (12753.50 mg / kg), magnesium (8642.50 mg / kg), calcium (3929.50 mg / kg), chlorine (24234.00 mg / kg), and iron (165.89 mg / kg). The nitrogen solubility index (NSI) was 83.64%, and the total amino acid content reached 647.21 mg / g, of which the essential amino acid content was 347.62 mg / g. The proportion of essential amino acids to total amino acids (EAA / TAA) was 53.71%, indicating an ideal amino acid pattern, all significantly exceeding the WHO / FAO recommended range, classifying it as a high-quality protein. It was rich in functional proteins, with albumin content of 311.47 mg / g, immunoglobulin Y (IgY) content as high as 93.57 mg / g, immunoglobulin M (IgM) content of 22.88 mg / g, and immunoglobulin A (IgA) content of 12.54 mg / g. The total bacterial count was 3.30 × 10⁻⁶. 5 CFU / g, total mold count was 9.50 × 10⁻⁶ 3 CFU / g; heavy metals lead and mercury were not detected, cadmium was detected at 0.03 mg / kg, chromium at 2.27 mg / kg, and arsenic at 1.12 mg / kg, all of which are far below the limits of GB13078-2017 "Feed Hygiene Standard".

9. The use of chicken plasma protein powder according to any one of claims 7 to 8 in the preparation of feed or feed additives.

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