Processing technology of corn starch for livestock and poultry feed
By employing processes such as ripening, primary dispersion, enzymatic hydrolysis, and secondary dispersion of corn starch, the problem of uneven particle size in corn starch powder has been solved, enabling efficient digestion and nutrient utilization of corn starch in livestock and poultry feed, thereby improving the growth performance of livestock and poultry.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KUNMING UNIVERSITY
- Filing Date
- 2026-03-13
- Publication Date
- 2026-04-10
AI Technical Summary
The uneven particle size of corn starch in current livestock and poultry feed processing leads to uneven mixing, insufficient or excessive maturation, affecting digestibility and utilization, increasing breeding costs, and lacking market competitiveness.
A continuous processing technology of corn starch, including ripening, primary dispersion, enzymatic hydrolysis, and secondary dispersion, was adopted. Lecithin and chitosan oligosaccharide were used as dispersants and enzymatic hydrolysis reagents, combined with high-pressure encapsulation treatment, to reduce starch agglomeration and improve particle size uniformity and flowability.
It significantly improves the digestibility and nutrient utilization of corn starch, enhances the mixing uniformity and digestibility of livestock and poultry feed, reduces agglomeration, and improves the growth performance of livestock and poultry.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of feed and production methods specifically applicable to livestock and poultry. More specifically, this invention relates to a processing technology for corn starch used in livestock and poultry feed. Background Technology
[0002] Corn is the most widely used raw material in industrial feed, and complete pelleted feed is currently the main product of livestock and poultry feed production. The particle size and uniformity of corn, as well as the degree of starch gelatinization, have a significant impact on the digestibility and utilization efficiency of the feed. However, current feed processing methods suffer from problems such as large dispersion and severe unevenness in corn particle size. This makes it difficult to control the mixing stage and subsequent cooking conditions in feed processing, easily leading to uneven mixing, insufficient cooking, and over-cooking. Consequently, this results in low utilization rates of livestock and poultry feed, high feed costs, and a lack of market competitiveness for livestock products.
[0003] Crushing raw materials increases the exposed surface area of the feed, enhancing contact between feed particles and digestive enzymes, thus promoting animal digestion and absorption. As particle size decreases, material flowability and bulk density decrease, while the angle of repose of the feed pile increases. Controlling the particle size within a reasonable range improves production efficiency. Uniform mixing of raw materials and additives forms the basis for nutritional and quality control in livestock and poultry feed formulations. The closer the particle size of the raw materials in the feed, the easier it is to mix evenly, and the lower the tendency for material grading during subsequent processing. Particle size significantly affects the quality of pelleted feed. Reducing particle size facilitates subsequent mixing, preventing cracks in the finished feed pellets due to large particles, thus reducing pulverization. During conditioning, smaller particles allow steam to penetrate more easily, resulting in more thorough contact, increased starch gelatinization, and better conditioning effects.
[0004] Starch is a polymer composed of D-glucose monomers and is the main storage form of carbohydrates in plants. Starch structure includes granule size, morphology, amylose and amylopectin composition, and crystallinity. High pressure, steam, temperature, and cooking time during the maturation process significantly affect starch structure, thus influencing starch gelatinization. Granule size affects the maturation process and subsequent digestion and absorption of starch; maturation conditions influence granule size. Extrusion puffing can break intermolecular hydrogen bonds, causing starch gelatinization to form α-starch, and also breaks intramolecular 1,4-glycosidic bonds, resulting in a decrease in starch content and granule expansion in the extruded product. While maturation causes starch granules to expand and gelatinize, the optimal degree of granule size change for optimal feed maturation warrants further investigation.
[0005] During feed maturation, the total starch content, rapidly digestible starch content, resistant starch content, and amylose-to-amylopectin ratio change. Amylose content is positively correlated with the formation of resistant starch after high-temperature cooking, while amylopectin is more sensitive to starch maturation. Different starch particle sizes have significantly different digestibility; puffing ordinary corn starch significantly disrupts its crystalline structure. Higher amylose content corresponds to lower starch crystallinity. Starch crystallinity directly affects the digestibility and absorption by livestock and poultry.
[0006] Therefore, the corn starch cooking process has a significant impact on the microscopic particle size and morphology of corn starch, as well as the types of corn starch. Summary of the Invention
[0007] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.
[0008] To achieve these and other advantages according to the present invention, the present invention provides a processing method for corn starch for livestock and poultry feed, comprising the following steps: Step 1: Screen and grind the corn starch, and then cook it to obtain a cooked corn starch slurry; Step 2: Use lecithin as a dispersant to perform primary dispersion of the matured corn starch slurry; Step 3: Use chitosan oligosaccharide and pullulanase as enzymatic hydrolysis reagents to enzymatically hydrolyze the primary dispersed corn starch slurry; Step 4: Secondary dispersion and resolution of the enzymatically hydrolyzed corn starch, followed by drying to obtain refined corn starch for livestock and poultry feed.
[0009] Preferably, in step one, the particle size of the corn starch after screening and grinding is ≤40μm.
[0010] Preferably, the specific method for maturing corn starch in step one includes: putting corn starch into a reaction vessel, adding pure water, starting stirring, setting the stirring speed to 60~120 rpm to obtain corn starch slurry; uniformly spraying in a food-grade sulfurous acid solution preheated at 60℃, the food-grade sulfurous acid solution having a volume concentration of 0.15% (calculated as SO2), maintaining the stirring speed and raising the temperature to 60~80℃ while spraying, keeping it at that temperature for 30~60 min, and cooling to room temperature to obtain the maturated corn starch slurry.
[0011] Preferably, the ratio of corn starch to pure water is 1~10g:10~100mL; and the volume ratio of food-grade sulfurous acid solution to pure water is 1~1.5:1.
[0012] Preferably, in step two, the method for primary dispersion of the matured corn starch slurry includes: heating the corn starch slurry to 50-65°C, adding pre-dissolved lecithin to the corn starch slurry, setting the ultrasonic frequency to 30-60kHz, the power density to 50-60W / L, working for 5 seconds and then pausing for 2 seconds, setting the ultrasonic time to 15-30 minutes, and obtaining the primary dispersed corn starch slurry.
[0013] Preferably, lecithin accounts for 0.3% to 1.5% of the mass of corn starch.
[0014] Preferably, in step three, the specific method for enzymatically hydrolyzing the primary dispersed corn starch slurry using chitosan oligosaccharide and pullulanase as enzymatic hydrolysis reagents includes: The pH of the corn starch slurry was adjusted to 5.5-6.0 using citrate buffer. Chitosan oligosaccharide and pullulanase were added sequentially, and the temperature was raised to 55-60℃. The mixture was stirred at 80-240 rpm for 2-6 hours. After standing, the supernatant was removed, and the lower precipitate was dried to obtain the enzymatically hydrolyzed corn starch. The amount of chitosan oligosaccharide used was 10-20% of the mass of corn starch, and the amount of pullulanase used was 1%-5% of the mass of corn starch.
[0015] Preferably, the specific method of step four includes: The enzymatically hydrolyzed corn starch was dispersed in a 0.5 wt% citric acid solution, heated to 50°C and stirred for 30 min at a stirring speed of 120-200 rpm. The mixture was then centrifuged at 5000 rpm for 15-20 min. The precipitate was separated and reconstituted. A 0.1 wt% β-glucan aqueous solution was added, and the mixture was pressurized at 3-12 MPa for 5-10 min. The precipitate was filtered out, washed multiple times, and then spray-dried at an inlet air temperature of 180°C and an outlet air temperature of 85°C to ensure the solid moisture content was ≤8%, thus obtaining refined corn starch for livestock and poultry feed. The ratio of enzymatically hydrolyzed corn starch, citric acid solution, and β-glucan aqueous solution was 1-10 g: 5-100 mL: 20-150 mL.
[0016] Preferably, an equal amount of modified lecithin is used to replace the lecithin in step two, and the method for preparing the modified lecithin includes: S1. Soybean lecithin was selected. Under a nitrogen atmosphere, soybean lecithin was added to food-grade ethyl acetate, food-grade citric acid was added as a carboxylation reagent, and anhydrous sodium acetate was added as a catalyst. The reaction system was heated to 50℃ and kept at that temperature for 3-6 hours. After cooling, 0.5% sodium bicarbonate solution was added to adjust the pH to 7.0. Ethyl acetate was removed by vacuum distillation at 0.09 MPa and 60℃. Pure water was added, and impurities were removed by ultrafiltration through a 10kDa membrane to remove byproducts with a molecular weight <1kDa, thus obtaining carboxylated soybean lecithin. S2. Disperse carboxylated soybean lecithin in food-grade ethyl acetate, add L-lactic acid, heat to 40℃ and keep warm for 1~6h, cool to room temperature, heat to 80℃ and keep warm for 30min, remove ethyl acetate by vacuum distillation at 0.09MPa and 60℃, wash the solid with pure water several times, and dry to obtain modified lecithin.
[0017] Preferably, in S1, the ratio of soybean lecithin, food-grade ethyl acetate, food-grade citric acid, and anhydrous sodium acetate is 1 kg: 4~5 L: 120~180 mL: 30~60 g. In S2, the ratio of carboxylated soybean lecithin, food-grade ethyl acetate, and L-lactic acid is 1 kg: 3~4 L: 30~40 mL.
[0018] The present invention has at least the following beneficial effects: The present invention provides a continuous processing technology of corn starch maturation → primary dispersion → enzymatic modification → secondary dispersion, which yields corn starch with narrower particle size distribution, more uniform particle size and lower agglomeration. When the refined corn starch is applied to livestock and poultry feed, it can significantly improve the digestibility and nutrient utilization rate of corn starch.
[0019] First, sulfurous acid is used to mature corn starch. Sulfurous acid depolymerizes the glycosidic bonds in the amorphous region of corn starch, reducing the crystallinity of corn starch and forming a "pore network" in the amorphous region of corn starch, providing a pathway for pullulanase molecules to enter the interior of the particles. At the same time, sulfurous acid dissolves the hydrophobic phospholipid layer on the surface of corn starch, exposing hydrophilic groups, which is beneficial for subsequent dispersant dispersion and chitosan oligosaccharide grafting. Then, lecithin was used as a dispersant for ultrasonic dispersion. The hydrophobic end of lecithin was embedded in the hydrophobic cavity of starch, and the hydrophilic end was exposed to form a hydration layer. A hydration layer was formed on the surface of corn starch, which changed the surface of corn kernels from hydrophobic to hydrophilic. At the same time, the dispersant enhanced the spatial steric hindrance effect and electrostatic repulsion between corn starch kernels. Through the synergistic effect of ultrasonic cavitation, the agglomeration of corn starch was reduced. Pullulanase cleaves the α-1,6 glycosidic bonds of corn starch. Chitosan oligosaccharide is grafted onto exposed hydrophilic groups (such as hydroxyl groups) and the broken chain sites via hydrogen bonds. The short-chain corn starch fragments produced by enzymatic hydrolysis diffuse outward through channels and are captured by chitosan oligosaccharide in time, preventing the fragments from re-aggregating. That is, the role of this step is to block the re-aggregation and recrystallization between corn starch particles. The final high-pressure encapsulation treatment allows β-glucan to penetrate into the micropores of corn starch particles at 5 MPa, forming a steric hindrance layer between the corn starch particles, inhibiting the flocculation of corn starch, and thus further reducing the agglomeration of corn starch.
[0020] Among these methods, the modification of lecithin with citric acid and L-lactic acid improved its dispersibility and further reduced the agglomeration of corn starch. Carboxylation increased the HLB value of lecithin, while L-lactic acid increased the density of carboxyl and hydroxyl groups in lecithin, enhancing its ability to bond with corn starch via hydrogen bonds, making it easier for lecithin to anchor to the hydrophobic regions of corn starch. Carboxylation and hydroxylation extended the chain length of lecithin, thereby enhancing the steric hindrance effect formed during lecithin dispersion, reducing the liquid-solid interface energy between the dispersion medium and corn starch, allowing the hydration layer to fully and uniformly coat the corn starch particles, improving the ultrasonic cavitation efficiency, and thus enhancing the dispersion ability of lecithin on corn starch, resulting in a more uniform particle size distribution of corn starch.
[0021] Meanwhile, the above-mentioned processing technology adopted in this invention takes into account both the improvement of corn starch dispersibility and flowability, that is, while obtaining good dispersibility of corn starch, it also gives it good flowability.
[0022] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation
[0023] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.
[0024] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.
[0025] Example 1
[0026] A processing method for corn starch for livestock and poultry feed includes the following steps: Step 1: Add 1 kg of corn starch to a reaction vessel, add 10 L of pure water, start stirring, and set the stirring speed to 60 rpm to obtain corn starch slurry; uniformly spray in 10 L of food-grade sulfurous acid solution preheated at 60℃. The food-grade sulfurous acid solution is calculated as SO2 with a volume concentration of 0.15%. While spraying, maintain the stirring speed and raise the temperature to 65℃, keep it at that temperature for 50 min, and cool to room temperature to obtain the cooked corn starch slurry. Step 2: Heat the corn starch slurry to 65℃, add 200mL of solution pre-dissolved 10g of lecithin (pre-dissolved in 65℃ warm water) to the corn starch slurry, set the ultrasonic frequency to 30kHz, the power density to 50W / L, work for 5s and then pause for 2s, set the ultrasonic time to 20min, and obtain the primary dispersed corn starch slurry. Step 3: Adjust the pH of the corn starch slurry to 6.0 using citrate buffer, add 100g of chitosan oligosaccharide and 10g of pullulanase in sequence, heat to 60℃, stir at 100rpm for 3 hours, remove the supernatant after standing, and dry the lower precipitate to obtain the enzymatically hydrolyzed corn starch. Step 4: Disperse 1 kg of enzymatically hydrolyzed corn starch into 5 L of 0.5 wt% citric acid solution, heat to 50℃ and stir for 30 min at 120 rpm, centrifuge at 5000 rpm for 20 min, separate and redissolve the precipitate, add 20 L of 0.1 wt% β-glucan aqueous solution, maintain pressure at 5 MPa for 10 min, filter out the precipitate, wash several times, and spray dry, setting the inlet air temperature to 180℃ and the outlet air temperature to 85℃, so that the moisture content of the solid reaches 3%, to obtain refined corn starch for livestock and poultry feed.
[0027] Example 2
[0028] A processing method for corn starch for livestock and poultry feed includes the following steps: Step 1: Add 1 kg of corn starch to a reaction vessel, add 10 L of pure water, start stirring, and set the stirring speed to 60 rpm to obtain corn starch slurry; uniformly spray in 10 L of food-grade sulfurous acid solution preheated at 60℃. The food-grade sulfurous acid solution is calculated as SO2 with a volume concentration of 0.15%. While spraying, maintain the stirring speed and raise the temperature to 65℃, keep it at that temperature for 50 min, and cool to room temperature to obtain the cooked corn starch slurry. Step 2: Heat the corn starch slurry to 65℃, add 200mL of solution pre-dissolved 8g of lecithin (pre-dissolved in 65℃ warm water) to the corn starch slurry, set the ultrasonic frequency to 30kHz, the power density to 50W / L, work for 5s and then pause for 2s, set the ultrasonic time to 20min, and obtain the primary dispersed corn starch slurry. Step 3: Adjust the pH of the corn starch slurry to 6.0 using citrate buffer, add 120g of chitosan oligosaccharide and 30g of pullulanase in sequence, heat to 60℃, stir at 100rpm for 3 hours, remove the supernatant after standing, and dry the lower precipitate to obtain the enzymatically hydrolyzed corn starch. Step 4: Disperse 1 kg of enzymatically hydrolyzed corn starch into 5 L of 0.5 wt% citric acid solution, heat to 50℃ and stir for 30 min at 120 rpm, centrifuge at 5000 rpm for 20 min, separate and redissolve the precipitate, add 20 L of 0.1 wt% β-glucan aqueous solution, maintain pressure at 5 MPa for 10 min, filter out the precipitate, wash several times, and spray dry, setting the inlet air temperature to 180℃ and the outlet air temperature to 85℃, so that the moisture content of the solid reaches 3%, to obtain refined corn starch for livestock and poultry feed.
[0029] Example 3
[0030] A processing method for corn starch for livestock and poultry feed includes the following steps: Step 1: Add 1 kg of corn starch to a reaction vessel, add 10 L of pure water, start stirring, and set the stirring speed to 60 rpm to obtain corn starch slurry; uniformly spray in 10 L of food-grade sulfurous acid solution preheated at 60℃. The food-grade sulfurous acid solution is calculated as SO2 with a volume concentration of 0.15%. While spraying, maintain the stirring speed and raise the temperature to 65℃, keep it at that temperature for 50 min, and cool to room temperature to obtain the cooked corn starch slurry. Step 2: Heat the corn starch slurry to 65℃, add 200mL of solution pre-dissolved 5g of lecithin (pre-dissolved in 65℃ warm water) to the corn starch slurry, set the ultrasonic frequency to 30kHz, the power density to 50W / L, work for 5s and then pause for 2s, set the ultrasonic time to 20min, and obtain the primary dispersed corn starch slurry. Step 3: Adjust the pH of the corn starch slurry to 6.0 using citrate buffer, add 150g of chitosan oligosaccharide and 50g of pullulanase in sequence, heat to 60℃, stir at 100rpm for 3 hours, remove the supernatant after standing, and dry the lower precipitate to obtain the enzymatically hydrolyzed corn starch. Step 4: Disperse 1 kg of enzymatically hydrolyzed corn starch into 5 L of 0.5 wt% citric acid solution, heat to 50℃ and stir for 30 min at 120 rpm, centrifuge at 5000 rpm for 20 min, separate and redissolve the precipitate, add 20 L of 0.1 wt% β-glucan aqueous solution, maintain pressure at 5 MPa for 10 min, filter out the precipitate, wash several times, and spray dry, setting the inlet air temperature to 180℃ and the outlet air temperature to 85℃, so that the moisture content of the solid reaches 3%, to obtain refined corn starch for livestock and poultry feed.
[0031] Example 4
[0032] A processing method for corn starch for livestock and poultry feed includes the following steps: Step 1: Add 1 kg of corn starch to a reaction vessel, add 10 L of pure water, start stirring, and set the stirring speed to 60 rpm to obtain corn starch slurry; uniformly spray in 10 L of food-grade sulfurous acid solution preheated at 60℃. The food-grade sulfurous acid solution is calculated as SO2 with a volume concentration of 0.15%. While spraying, maintain the stirring speed and raise the temperature to 65℃, keep it at that temperature for 50 min, and cool to room temperature to obtain the cooked corn starch slurry. Step 2: Heat the corn starch slurry to 65℃, add 200mL of a solution pre-dissolved with 10g of modified lecithin (pre-dissolved in 65℃ warm water), set the ultrasonic frequency to 30kHz, the power density to 50W / L, work for 5s followed by a 2s interval, and set the ultrasonic time to 20min to obtain a primary dispersed corn starch slurry; wherein, the preparation method of the modified lecithin includes: S1. Under a nitrogen atmosphere, 1 kg of soybean lecithin was added to 4 L of food-grade ethyl acetate, 120 mL of food-grade citric acid was added as a carboxylation reagent, and 30 g of anhydrous sodium acetate was added as a catalyst. The reaction system was heated to 50 °C and kept at that temperature for 3 h. After cooling, 0.5% sodium bicarbonate solution was added to adjust the pH to 7.0. Ethyl acetate was removed by vacuum distillation at 0.09 MPa and 60 °C. Pure water was added, and impurities were removed by ultrafiltration through a 10 kDa membrane to remove byproducts with a molecular weight <1 kDa, thus obtaining carboxylated soybean lecithin. S2. Disperse 1 kg of carboxylated soybean lecithin in 3 L of food-grade ethyl acetate, add 35 mL of L-lactic acid, heat to 40 °C and keep warm for 2 h, cool to room temperature, heat to 80 °C and keep warm for 30 min, remove ethyl acetate by vacuum distillation at 0.09 MPa and 60 °C, wash the solid with pure water several times, and dry to obtain modified lecithin.
[0033] Step 3: Adjust the pH of the corn starch slurry to 6.0 using citrate buffer, add 100g of chitosan oligosaccharide and 10g of pullulanase in sequence, heat to 60℃, stir at 100rpm for 3 hours, remove the supernatant after standing, and dry the lower precipitate to obtain the enzymatically hydrolyzed corn starch. Step 4: Disperse 1 kg of enzymatically hydrolyzed corn starch into 5 L of 0.5 wt% citric acid solution, heat to 50℃ and stir for 30 min at 120 rpm, centrifuge at 5000 rpm for 20 min, separate and redissolve the precipitate, add 20 L of 0.1 wt% β-glucan aqueous solution, maintain pressure at 5 MPa for 10 min, filter out the precipitate, wash several times, and spray dry, setting the inlet air temperature to 180℃ and the outlet air temperature to 85℃, so that the moisture content of the solid reaches 3%, to obtain refined corn starch for livestock and poultry feed.
[0034] Example 5
[0035] A processing method for corn starch for livestock and poultry feed includes the following steps: Step 1: Add 1 kg of corn starch to a reaction vessel, add 10 L of pure water, start stirring, and set the stirring speed to 60 rpm to obtain corn starch slurry; uniformly spray in 10 L of food-grade sulfurous acid solution preheated at 60℃. The food-grade sulfurous acid solution is calculated as SO2 with a volume concentration of 0.15%. While spraying, maintain the stirring speed and raise the temperature to 65℃, keep it at that temperature for 50 min, and cool to room temperature to obtain the cooked corn starch slurry. Step 2: Heat the corn starch slurry to 65℃, add 200mL of a solution pre-dissolved with 10g of modified lecithin (pre-dissolved in 65℃ warm water), set the ultrasonic frequency to 30kHz, the power density to 50W / L, work for 5s followed by a 2s interval, and set the ultrasonic time to 20min to obtain a primary dispersed corn starch slurry; wherein, the preparation method of the modified lecithin includes: S1. Under a nitrogen atmosphere, 1 kg of soybean lecithin was added to 5 L of food-grade ethyl acetate, 150 mL of food-grade citric acid was added as a carboxylation reagent, and 50 g of anhydrous sodium acetate was added as a catalyst. The reaction system was heated to 50 °C and kept at that temperature for 3 h. After cooling, 0.5% sodium bicarbonate solution was added to adjust the pH to 7.0. The ethyl acetate was removed by vacuum distillation at 0.09 MPa and 60 °C. Pure water was added, and the mixture was ultrafiltered through a 10 kDa membrane to remove impurities and remove byproducts with a molecular weight <1 kDa, thus obtaining carboxylated soybean lecithin. S2. Disperse 1 kg of carboxylated soybean lecithin in 3 L of food-grade ethyl acetate, add 40 mL of L-lactic acid, heat to 40 °C and keep warm for 2 h, cool to room temperature, heat to 80 °C and keep warm for 30 min, remove ethyl acetate by vacuum distillation at 0.09 MPa and 60 °C, wash the solid with pure water several times, and dry to obtain modified lecithin.
[0036] Step 3: Adjust the pH of the corn starch slurry to 6.0 using citrate buffer, add 100g of chitosan oligosaccharide and 10g of pullulanase in sequence, heat to 60℃, stir at 100rpm for 3 hours, remove the supernatant after standing, and dry the lower precipitate to obtain the enzymatically hydrolyzed corn starch. Step 4: Disperse 1 kg of enzymatically hydrolyzed corn starch into 5 L of 0.5 wt% citric acid solution, heat to 50℃ and stir for 30 min at 120 rpm, centrifuge at 5000 rpm for 20 min, separate and redissolve the precipitate, add 20 L of 0.1 wt% β-glucan aqueous solution, maintain pressure at 5 MPa for 10 min, filter out the precipitate, wash several times, and spray dry, setting the inlet air temperature to 180℃ and the outlet air temperature to 85℃, so that the moisture content of the solid reaches 3%, to obtain refined corn starch for livestock and poultry feed.
[0037] Comparative Example 1 A processing method for corn starch for livestock and poultry feed includes the following steps: Step 1: Add 1 kg of corn starch to a reaction vessel, add 10 L of pure water, start stirring, and set the stirring speed to 60 rpm to obtain corn starch slurry; uniformly spray in 10 L of food-grade sulfurous acid solution preheated at 60℃. The food-grade sulfurous acid solution is calculated as SO2 with a volume concentration of 0.15%. While spraying, maintain the stirring speed and raise the temperature to 65℃, keep it at that temperature for 50 min, and cool to room temperature to obtain the cooked corn starch slurry. Step 2: Heat the corn starch slurry to 65℃, add 200mL of solution pre-dissolved 10g of lecithin (pre-dissolved in 65℃ warm water) to the corn starch slurry, set the ultrasonic frequency to 30kHz, the power density to 50W / L, work for 5s and then pause for 2s, set the ultrasonic time to 20min, and obtain the primary dispersed corn starch slurry. Step 3: Dry the primary dispersed corn starch slurry to obtain primary corn starch; Step 4: Disperse 1 kg of primary corn starch into 5 L of 0.5 wt% citric acid solution, heat to 50℃ and stir for 30 min at a stirring speed of 120 rpm. Centrifuge at 5000 rpm for 20 min to separate and redissolve the precipitate. Add 20 L of 0.1 wt% β-glucan aqueous solution and maintain pressure at 5 MPa for 10 min. Filter out the precipitate, wash it several times, and then spray dry it. Set the inlet air temperature to 180℃ and the outlet air temperature to 85℃ to make the moisture content of the solids reach 3% to obtain refined corn starch for livestock and poultry feed.
[0038] The particle size distribution of refined corn starch from Examples 1-5 and Comparative Example 1, as well as unrefined corn starch, was measured respectively, and the results are shown in the table below: Table 1 Particle size distribution data of various corn starch samples
[0039] As can be seen from the table above, the corn starch particles refined in Examples 1-5 have a more uniform particle size distribution, a narrower particle size range, and a less refined degree. Among them, Examples 4 and 5 used modified lecithin as a dispersant for primary dispersion, and the resulting corn starch particle size distribution was significantly better than that in Examples 1-3, indicating that modified lecithin played a very crucial role in refining the corn starch.
[0040] Meanwhile, the particle size distribution of refined corn starch from Examples 1-5, Comparative Example 1, and unrefined corn starch were measured, and the results are shown in the table below: Table 2 Angle of repose for each corn starch sample
[0041] As can be seen from the table above, the corn starch after the fine dispersion treatment in Examples 1-4 has a smaller angle of repose, indicating that the corn starch obtained by the process of the present invention not only has good dispersibility but also excellent flow properties. When mixing and feeding livestock and poultry feed, it is easier to mix with other components of the feed, and it is easier for livestock and poultry to digest and absorb the nutrients of corn starch, thereby improving the utilization efficiency of corn starch nutrients.
[0042] The basal diets were formulated using Examples 1-5, Comparative Example 1, and unrefined corn starch, respectively. Each basal diet consisted of 57% corn starch (from Examples 1-5, Comparative Example 1, and unrefined starch by weight), 31% soybean meal, 4.5% corn gluten meal, 3.6% soybean oil, 2% dicalcium phosphate, 1.2% limestone powder, 0.3% L-lysine, 0.1% DL-methionine, and 0.3% salt. These basal diets were fed to 350 one-day-old AA broiler chickens. The chickens were divided into seven groups and fed the basal diets formulated using Examples 1-5, Comparative Example 1, and unrefined corn starch, respectively, for 21 days. Each AA broiler chicken in each group was weighed daily on an empty stomach, and feed intake was recorded. The average daily weight gain, average daily feed intake, and feed conversion ratio were calculated for each group, as shown in the table below. Table 3 Comparison of data from different groups fed with added corn starch
[0043] As can be seen from the table above, the experimental groups fed with the refined corn starch prepared in Examples 4 and 5 had better feed conversion ratios than the other experimental groups and the control group. This indicates that refining corn starch using the method of the present invention can significantly improve the conversion rate of feed nutrients in AA broilers and promote their growth.
[0044] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.
[0045] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.
Claims
1. A processing technology for corn starch used in livestock and poultry feed, characterized in that, Includes the following steps: Step 1: Screen and grind the corn starch, and then cook it to obtain a cooked corn starch slurry; Step 2: Use lecithin as a dispersant to perform primary dispersion of the matured corn starch slurry; Step 3: Use chitosan oligosaccharide and pullulanase as enzymatic hydrolysis reagents to enzymatically hydrolyze the primary dispersed corn starch slurry; Step 4: Secondary dispersion and resolution of the enzymatically hydrolyzed corn starch, followed by drying to obtain refined corn starch for livestock and poultry feed.
2. The processing technology for corn starch for livestock and poultry feed as described in claim 1, characterized in that, In step one, the particle size of the corn starch after screening and grinding is ≤40μm.
3. The processing technology for corn starch for livestock and poultry feed as described in claim 1, characterized in that, In step one, the specific method for maturing corn starch includes: putting corn starch into a reaction vessel, adding pure water, starting stirring, setting the stirring speed to 60~120 rpm to obtain corn starch slurry; uniformly spraying in a food-grade sulfurous acid solution preheated at 60℃, the food-grade sulfurous acid solution being calculated as SO2 with a volume concentration of 0.15%, while maintaining the stirring speed and raising the temperature to 60~80℃, keeping it at that temperature for 30~60 minutes, and cooling it to room temperature to obtain the maturated corn starch slurry.
4. The processing technology for corn starch for livestock and poultry feed as described in claim 3, characterized in that, The ratio of corn starch to pure water is 1~10g:10~100mL; the volume ratio of food-grade sulfurous acid solution to pure water is 1~1.5:
1.
5. The processing technology for corn starch for livestock and poultry feed as described in claim 1, characterized in that, In step two, the method for primary dispersion of the matured corn starch slurry includes: heating the corn starch slurry to 50~65℃, adding pre-dissolved lecithin to the corn starch slurry, setting the ultrasonic frequency to 30~60kHz, the power density to 50~60W / L, working for 5s and then pausing for 2s, setting the ultrasonic time to 15~30min, and obtaining the primary dispersed corn starch slurry.
6. The processing technology for corn starch for livestock and poultry feed as described in claim 5, characterized in that, Lecithin accounts for 0.3% to 1.5% of the mass of corn starch.
7. The processing technology for corn starch for livestock and poultry feed as described in claim 1, characterized in that, In step three, the specific method for enzymatically hydrolyzing the primary dispersed corn starch slurry using chitosan oligosaccharide and pullulanase as enzymatic hydrolysis reagents includes: The pH of the corn starch slurry was adjusted to 5.5-6.0 using citrate buffer. Chitosan oligosaccharide and pullulanase were added sequentially, and the temperature was raised to 55-60℃. The mixture was stirred at 80-240 rpm for 2-6 hours. After standing, the supernatant was removed, and the lower precipitate was dried to obtain the enzymatically hydrolyzed corn starch. The amount of chitosan oligosaccharide used was 10%-20% of the mass of corn starch, and the amount of pullulanase used was 1%-5% of the mass of corn starch.
8. The processing technology for corn starch for livestock and poultry feed as described in claim 1, characterized in that, The specific methods for step four include: The enzymatically hydrolyzed corn starch was dispersed in a 0.5 wt% citric acid solution, heated to 50°C and stirred for 30 min at a stirring speed of 120-200 rpm. The mixture was then centrifuged at 5000 rpm for 15-20 min. The precipitate was separated and reconstituted. A 0.1 wt% β-glucan aqueous solution was added, and the mixture was pressurized at 3-12 MPa for 5-10 min. The precipitate was filtered out, washed multiple times, and then spray-dried at an inlet air temperature of 180°C and an outlet air temperature of 85°C to ensure the solid moisture content was ≤8%, thus obtaining refined corn starch for livestock and poultry feed. The ratio of enzymatically hydrolyzed corn starch, citric acid solution, and β-glucan aqueous solution was 1-10 g: 5-100 mL: 20-150 mL.
9. The processing technology for corn starch for livestock and poultry feed as described in claim 1, characterized in that, The modified lecithin is prepared by replacing the lecithin in step two with an equal amount of modified lecithin. S1. Soybean lecithin was selected. Under a nitrogen atmosphere, soybean lecithin was added to food-grade ethyl acetate, food-grade citric acid was added as a carboxylation reagent, and anhydrous sodium acetate was added as a catalyst. The reaction system was heated to 50℃ and kept at that temperature for 3-6 hours. After cooling, 0.5% sodium bicarbonate solution was added to adjust the pH to 7.
0. Ethyl acetate was removed by vacuum distillation at 0.09 MPa and 60℃. Pure water was added, and impurities were removed by ultrafiltration through a 10kDa membrane to remove byproducts with a molecular weight <1kDa, thus obtaining carboxylated soybean lecithin. S2. Disperse carboxylated soybean lecithin in food-grade ethyl acetate, add L-lactic acid, heat to 40℃ and keep warm for 1~6h, cool to room temperature, heat to 80℃ and keep warm for 30min, remove ethyl acetate by vacuum distillation at 0.09MPa and 60℃, wash the solid with pure water several times, and dry to obtain modified lecithin.
10. The processing technology for corn starch for livestock and poultry feed as described in claim 9, characterized in that, In S1, the ratio of soybean lecithin, food-grade ethyl acetate, food-grade citric acid, and anhydrous sodium acetate is 1kg:4~5L:120~180mL:30~60g. In S2, the ratio of carboxylated soybean lecithin, food-grade ethyl acetate, and L-lactic acid is 1 kg: 3~4 L: 30~40 mL.