Rice polypeptide ferrous chelate microcapsule and preparation method thereof

Abstract

This invention relates to a method for preparing rice polypeptide ferrous chelate microcapsules based on the graded utilization of rice polypeptides. The method mainly includes the following steps: S1 preparation of rice polypeptides, S2 preparation of rice polypeptide ferrous chelates, and S3 microencapsulation of the rice polypeptide ferrous chelates. This invention uses widely available and inexpensive rice protein as the peptide source to obtain both low-molecular-weight and high-molecular-weight rice polypeptides. The low-molecular-weight rice polypeptides are used to chelate ferrous ions, while the high-molecular-weight rice polypeptides and yeast dextran constitute a composite wall material. The homologous synergistic system of the wall material and core material, as well as the coupling process of pre-activation of the wall material and micro-dispersion of the core material in the key emulsification stage, increase the stability and improve the quality of the product. Furthermore, the preparation method is simple, low-cost, and operates under mild conditions, making it suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of food fortification technology, and particularly relates to a polypeptide ferrous chelate microcapsule based on the graded utilization of rice polypeptides and its preparation method. Background Technology

[0002] Rice protein is a high-quality plant protein with advantages such as a balanced amino acid composition, low allergenicity, and easy digestibility and absorption. Rice peptides prepared from rice protein not only retain the nutritional properties of rice protein but also have better solubility, stability, and bioactivity.

[0003] Iron is one of the most abundant and easily deficient trace elements in the human body, playing a vital role with various physiological functions and importance. Iron deficiency can lead to a range of health problems, including iron-deficiency anemia. Traditional iron supplements, such as ferrous sulfate and ferrous glycine, while having high iron content, suffer from drawbacks such as a strong metallic taste, poor palatability, severe gastrointestinal irritation, instability, and low bioavailability. Currently, iron supplements, represented by peptide iron, offer advantages such as fewer side effects, high absorption and utilization rates, and both functionality and nutritional value. While peptide chelated iron shows promising application prospects, its practical application faces numerous challenges. Iron ions are sensitive to light and oxygen, easily oxidized and deactivated. High temperatures and humidity can degrade peptide chains, destroying the chelate structure and shortening shelf life. Furthermore, its unique taste and flavor may affect the sensory quality of the product, limiting its application. Microencapsulation technology can encapsulate the core material, improving stability, properties, and enabling controlled release. Introducing this technology holds promise for solving the challenges of peptide chelated iron. Summary of the Invention

[0004] This invention aims to provide a method for preparing rice polypeptide ferrous chelate microcapsules based on the graded utilization of rice polypeptides. This method can prepare rice polypeptide ferrous chelate microcapsules with high encapsulation efficiency and strong stability.

[0005] To achieve the above objectives, the present invention employs the following technical solution: a method for preparing rice polypeptide ferrous chelate microcapsules, comprising the following steps:

[0006] Step S1: Preparation of rice polypeptides: Rice protein was used as raw material, and rice polypeptides were obtained by enzymatic hydrolysis. Rice protein was dissolved in deionized water to prepare a 10% (w / w) solution. Protease was added in a certain proportion, the pH was adjusted, and the solution was reacted at a certain temperature for a period of time to obtain rice protein hydrolysate. The obtained hydrolysate was separated by ultrafiltration membrane (molecular weight cutoff of 3000 Da). The filtrate with molecular weight less than 3000 Da and molecular weight greater than 3000 Da was collected and freeze-dried.

[0007] Step S2, Preparation of rice polypeptide ferrous chelate: Dissolve the low molecular weight rice polypeptide obtained in S1 in deionized water to prepare a 10% (w / w) solution. Add inorganic ferrous salt in a certain proportion, adjust the pH, and react at a certain temperature for a period of time to obtain rice polypeptide ferrous chelate solution. Wash with a certain proportion of 95% ethanol, centrifuge to collect the precipitate, and vacuum dry to obtain low molecular weight rice polypeptide ferrous chelate.

[0008] Step S3: Microencapsulation of rice polypeptide ferrous chelate: The high molecular weight rice polypeptide obtained in S1 and yeast dextran (300-600 kDa) prepared as raw material are mixed evenly at a certain mass ratio and then added to deionized water to prepare a 10%-20% wall material solution. The wall material solution is first ultrasonicated, and then 0.3% transglutaminase is added for gentle catalysis at 30℃ to obtain a homogeneous and stable wall material solution. The rice polypeptide ferrous chelate solution is pre-dispersed into nano-sized droplets using a microfluidic homogenizer and then slowly injected into the wall material solution. The mixture is continuously stirred for 10-40 minutes using a high-speed stirrer. Finally, the emulsion is spray-dried to obtain rice polypeptide ferrous chelate microcapsules.

[0009] In step S1, the ultrafiltration membrane has a molecular weight cutoff of 3000 Da.

[0010] Furthermore, in step S1, the protease is one or more of alkaline protease, neutral protease, and papain.

[0011] Furthermore, in step S1, the protease is an alkaline protease with an enzyme amount of 2500-10000 U / g, a hydrolysis time of 1-4 h, a hydrolysis temperature of 40-70 ℃, and a pH value of 9-12.

[0012] Furthermore, in step S1, the protease is an alkaline protease with an enzyme amount of 7500 U / g, a hydrolysis time of 2 h, a hydrolysis temperature of 60 ℃, and a pH value of 10.

[0013] Furthermore, in step S2, the mass ratio of the small molecular weight rice peptides to the inorganic ferrous salt is 2:1-5:1, the reaction pH is 6-9, and the temperature is 50 ℃.

[0014] Furthermore, in step S2, the mass ratio of the low molecular weight rice peptide to the inorganic ferrous salt is 4:1, the pH value is 7, the reaction time is greater than or equal to 1 h, and the temperature is 50 ℃.

[0015] Furthermore, in step S3, the mass ratio of the high molecular weight rice peptide to yeast glucan is 2:1-5:1, the mass ratio of the low molecular weight rice peptide ferrous chelate to the wall material is 1:1-1:4, and the stirring time is greater than 30 minutes.

[0016] Furthermore, in step S3, the mass ratio of high molecular weight rice peptides to yeast glucan is 4:1, the mass ratio of low molecular weight rice peptide ferrous chelate to wall material is 1:3, and the stirring time is greater than 30 min.

[0017] Furthermore, the spray drying conditions in S3 are an inlet temperature of 150-170 ℃ and an outlet temperature of 80-90 ℃.

[0018] The principle of this invention is:

[0019] Low molecular weight rice peptides (typically less than 3000 Da) exhibit excellent solubility and flowability, enabling them to form stable chelates with ferrous ions more effectively, thus improving the bioavailability of ferrous ions. Simultaneously, their relatively simple molecular structure makes them easier to digest and absorb in the human body. High molecular weight rice peptides (typically greater than 3000 Da), on the other hand, possess good film-forming and adhesive properties, forming tough and stable thin film structures. This characteristic gives them a unique advantage as wall materials in microencapsulation technology, effectively encapsulating core materials and protecting them from external environmental influences. By utilizing rice peptides in a graded manner—allowing low molecular weight rice peptides to perform the chelation function with ferrous ions, while high molecular weight rice peptides participate in encapsulation as components of the wall material—the advantages of different molecular weight peptides can be fully utilized, achieving efficient resource utilization. On the one hand, this avoids the functional limitations of single molecular weight peptides, improving the overall performance of the product; on the other hand, obtaining two peptides with different functions from the same raw material reduces production costs and improves production efficiency.

[0020] The beneficial effects of this invention are:

[0021] (1) The rice polypeptide ferrous chelate microcapsules prepared by the present invention are the first to accurately classify rice polypeptides according to molecular weight. The small molecular weight rice polypeptides are used to chelate ferrous ions, and the large molecular weight rice polypeptides are used to construct the wall material, so as to realize the deep and efficient graded utilization of rice protein resources. Compared with the traditional single polypeptide utilization method, the comprehensive performance of the product is significantly improved.

[0022] (2) Innovatively, high molecular weight rice peptides and yeast glucan are selected as composite wall materials. High molecular weight rice peptides and low molecular weight rice peptides chelate iron to form a homologous synergistic system, which improves product stability; at the same time, the dual functions of yeast glucan in enhancing immunity and antioxidation make the microcapsules have the combined effects of iron supplementation and enhancing immunity.

[0023] (3) By performing a “ultrasound-enzymatic hydrolysis” composite pretreatment activation on the wall material solution and a micro-jet homogenizer pre-dispersion process on the core material, the coating efficiency of the wall material on the core material is further improved.

[0024] (4) The homogeneous synergistic system of the wall material and the core material of the present invention, as well as the coupling process of pre-activation of the wall material and micro-dispersion of the core material in the key emulsification process, have increased the stability of the product and improved the quality of the product. Attached Figure Description

[0025] Figure 1 The storage stability of rice polypeptide ferrous chelate microcapsules was demonstrated;

[0026] Figure 2 The in vitro simulated gastrointestinal digestive stability of rice polypeptide ferrous chelate microcapsules was demonstrated. Detailed Implementation

[0027] The following are specific embodiments of this application:

[0028] Example 1

[0029] Preparation of S1 rice peptides: 500.0 g of rice protein was weighed and dissolved in 4500 mL of deionized water to prepare a 10% rice protein solution. The pH of the solution was adjusted to 10 with 1 mol / L HCl and NaOH solutions. 18.75 g of alkaline proteolytic enzyme was added, and enzymatic hydrolysis was carried out at 60 °C for 2 h. After enzymatic hydrolysis, the mixture was heated in a boiling water bath for 10 min to inactivate the protease and precipitate the large molecular weight proteins. The mixture was then filtered and ultrafiltered using a 3 kDa ultrafiltration membrane. The filtrates containing small molecular weight rice peptides (less than 3000 Da) and large molecular weight rice peptides (greater than 3000 Da) were collected and lyophilized.

[0030] Preparation of S2 rice polypeptide ferrous chelate: Weigh 25.0 g of the low molecular weight rice polypeptide prepared in step S1, add 250 mL of deionized water to dissolve and prepare a 10% low molecular weight rice polypeptide solution. Adjust the pH to 6.0 with 1 mol / L NaOH solution, then add FeCl2·4H2O to make the mass ratio of low molecular weight rice polypeptide to FeCl2·4H2O 2:1. Stir the reaction at 50 ℃ for 1 h, wash with a certain proportion of 95% ethanol, centrifuge to collect the precipitate, and vacuum dry to obtain the low molecular weight rice polypeptide ferrous chelate.

[0031] Microencapsulation of rice polypeptide ferrous chelate (S3): The high molecular weight rice polypeptide and yeast dextran prepared in step S1 were added to deionized water at a mass ratio of 2:1 to prepare a 10% (w / w) composite wall material solution. The wall material solution was ultrasonically treated, and then 0.3% transglutaminase was added for gentle catalysis at 30°C to obtain a homogeneous and stable wall material solution. The low molecular weight rice polypeptide ferrous chelate solution prepared in step S2 was pre-dispersed into nano-sized droplets using a microfluidic homogenizer and then slowly injected into the wall material solution. At this point, the mass ratio of core material to wall material was 1:1. The mixed solution was continuously stirred for 10 min using a high-speed stirrer. Then, the emulsified emulsion was spray-dried at an inlet air temperature of 150°C and an outlet air temperature of 80°C to obtain rice polypeptide ferrous chelate microcapsules.

[0032] Example 2

[0033] Preparation of S1 rice peptides: 500.0 g of rice protein was weighed and dissolved in 4500 mL of deionized water to prepare a 10% rice protein solution. The pH of the solution was adjusted to 10 with 1 mol / L HCl and NaOH solutions. 18.75 g of alkaline proteolytic enzyme was added, and enzymatic hydrolysis was carried out at 60 °C for 2 h. After enzymatic hydrolysis, the mixture was heated in a boiling water bath for 10 min to inactivate the protease and precipitate the large molecular weight proteins. The mixture was then filtered and ultrafiltered using a 3 kDa ultrafiltration membrane. The filtrates containing small molecular weight rice peptides (less than 3000 Da) and large molecular weight rice peptides (greater than 3000 Da) were collected and lyophilized.

[0034] Preparation of S2 rice polypeptide ferrous chelate: Weigh 25.0 g of the low molecular weight rice polypeptide prepared in step S1, add 250 mL of deionized water to dissolve and prepare a 10% low molecular weight rice polypeptide solution. Adjust the pH to 7.0 with 1 mol / L NaOH solution, then add FeCl2·4H2O to make the mass ratio of low molecular weight rice polypeptide to FeCl2·4H2O 3:1. Stir the reaction at 50 ℃ for 1 h, wash with a certain proportion of 95% ethanol, centrifuge to collect the precipitate, and vacuum dry to obtain the low molecular weight rice polypeptide ferrous chelate.

[0035] Microencapsulation of rice polypeptide ferrous chelate (S3): The high molecular weight rice polypeptide prepared in step S1 and yeast dextran (prepared as raw material) were added to deionized water at a mass ratio of 3:1 to prepare a 10% (w / w) composite wall material solution. The wall material solution was ultrasonically treated, and then 0.3% transglutaminase was added for gentle catalysis at 30°C to obtain a homogeneous and stable wall material solution. The low molecular weight rice polypeptide ferrous chelate solution prepared in step S2 was pre-dispersed into nano-sized droplets using a microfluidic homogenizer and then slowly injected into the wall material solution. At this point, the mass ratio of core material to wall material was 1:2. The mixed solution was continuously stirred for 20 min using a high-speed stirrer. Then, the emulsified emulsion was spray-dried at an inlet air temperature of 160°C and an outlet air temperature of 80°C to obtain rice polypeptide ferrous chelate microcapsules.

[0036] Example 3

[0037] Preparation of S1 rice peptides: 500.0 g of rice protein was weighed and dissolved in 4500 mL of deionized water to prepare a 10% rice protein solution. The pH of the solution was adjusted to 10 with 1 mol / L HCl and NaOH solutions. 18.75 g of alkaline proteolytic enzyme was added, and enzymatic hydrolysis was carried out at 60 °C for 2 h. After enzymatic hydrolysis, the mixture was heated in a boiling water bath for 10 min to inactivate the protease and precipitate the large molecular weight proteins. The mixture was then filtered and ultrafiltered using a 3 kDa ultrafiltration membrane. The filtrates containing small molecular weight rice peptides (less than 3000 Da) and large molecular weight rice peptides (greater than 3000 Da) were collected and lyophilized.

[0038] Preparation of S2 rice polypeptide ferrous chelate: Weigh 25.0 g of the low molecular weight rice polypeptide prepared in step S1, add 250 mL of deionized water to dissolve and prepare a 10% low molecular weight rice polypeptide solution. Adjust the pH to 7.0 with 1 mol / L NaOH solution, then add FeCl2·4H2O to make the mass ratio of low molecular weight rice polypeptide to FeCl2·4H2O 4:1. Stir the reaction at 50 ℃ for 1 h, wash with a certain proportion of 95% ethanol, centrifuge to collect the precipitate, and vacuum dry to obtain the low molecular weight rice polypeptide ferrous chelate.

[0039] Microencapsulation of rice polypeptide ferrous chelate (S3): The high molecular weight rice polypeptide prepared in step S1 and yeast dextran (prepared as raw material) were added to deionized water at a mass ratio of 4:1 to prepare a 10% (w / w) composite wall material solution. The wall material solution was ultrasonically treated, and then 0.3% transglutaminase was added for gentle catalysis at 30°C to obtain a homogeneous and stable wall material solution. The low molecular weight rice polypeptide ferrous chelate solution prepared in step S2 was pre-dispersed into nano-sized droplets using a microfluidic homogenizer and then slowly injected into the wall material solution. At this point, the mass ratio of core material to wall material was 1:3. The mixed solution was continuously stirred for 30 min using a high-speed stirrer. Then, the emulsified emulsion was spray-dried at an inlet air temperature of 150°C and an outlet air temperature of 90°C to obtain rice polypeptide ferrous chelate microcapsules.

[0040] Example 4

[0041] Preparation of S1 rice peptides: 500.0 g of rice protein was weighed and dissolved in 4500 mL of deionized water to prepare a 10% rice protein solution. The pH of the solution was adjusted to 10 with 1 mol / L HCl and NaOH solutions. 18.75 g of alkaline proteolytic enzyme was added, and enzymatic hydrolysis was carried out at 60 °C for 2 h. After enzymatic hydrolysis, the mixture was heated in a boiling water bath for 10 min to inactivate the protease and precipitate the large molecular weight proteins. The mixture was then filtered and ultrafiltered using a 3 kDa ultrafiltration membrane. The filtrates containing small molecular weight rice peptides (less than 3000 Da) and large molecular weight rice peptides (greater than 3000 Da) were collected and lyophilized.

[0042] Preparation of S2 rice polypeptide ferrous chelate: Weigh 25.0 g of the low molecular weight rice polypeptide prepared in step S1, add 450 mL of deionized water to dissolve and prepare a 10% low molecular weight rice polypeptide solution. Adjust the pH to 8.0 with 1 mol / L NaOH solution, then add FeCl2·4H2O to make the mass ratio of low molecular weight rice polypeptide to FeCl2·4H2O 5:1. Stir the reaction at 50 ℃ for 1 h, wash with a certain proportion of 95% ethanol, centrifuge to collect the precipitate, and vacuum dry to obtain the low molecular weight rice polypeptide ferrous chelate.

[0043] Microencapsulation of rice polypeptide ferrous chelate (S3): The high molecular weight rice polypeptide prepared in step S1 and yeast dextran (prepared as raw material) were added to deionized water at a mass ratio of 5:1 to prepare a 10% (w / w) composite wall material solution. The wall material solution was ultrasonically treated, and then 0.3% transglutaminase was added for gentle catalysis at 30°C to obtain a homogeneous and stable wall material solution. The low molecular weight rice polypeptide ferrous chelate solution prepared in step S2 was pre-dispersed into nano-sized droplets using a microfluidic homogenizer and then slowly injected into the wall material solution. At this point, the mass ratio of core material to wall material was 1:4. The mixed solution was continuously stirred for 40 min using a high-speed stirrer. Then, the emulsified emulsion was spray-dried at an inlet air temperature of 150°C and an outlet air temperature of 90°C to obtain rice polypeptide ferrous chelate microcapsules.

[0044] Performance testing

[0045] (1) Determination of chelation rate of rice polypeptide ferrous chelate:

[0046] Chelation rate (%) = (Total amount of ferrous ions in the reaction solution - Content of free ferrous ions in the filtrate) / Total amount of ferrous ions in the reaction solution;

[0047] (2) Determination of encapsulation rate of rice polypeptide ferrous chelate microcapsules: Encapsulation rate (%) = Actual iron mass of rice polypeptide ferrous chelate in microencapsulated product / Theoretically added rice polypeptide chelate iron mass in microencapsulated product;

[0048] (3) In vitro stability determination of rice polypeptide ferrous chelate microcapsules:

[0049] ① Storage stability: The rice polypeptide ferrous chelate microcapsules and the unmicroencapsulated rice polypeptide ferrous chelate were placed in sealed bags and stored for 6 months under storage conditions of 40±2℃ and 75±5% humidity. The release of free ferrous ions was measured to evaluate their storage stability.

[0050] ② Stability analysis in simulated gastric and intestinal fluids: After preparing gastric and intestinal fluids, the pH was adjusted and heated to 37 ℃ for later use. FeCl2·4H2O with the same iron content, rice polypeptide ferrous chelate, and rice polypeptide ferrous chelate microcapsules from Example 3 were weighed and prepared into solutions of a certain concentration. Gastric and intestinal fluids were added respectively and reacted at 37 ℃ for 2 h. The release rate of free ferrous ions was measured to evaluate its stability.

[0051] Table 1. Chelation rate and iron content of rice polypeptide ferrous chelates (prepared in step S2) in Examples 1-4

[0052]

[0053] Table 2 Encapsulation efficiency of rice polypeptide ferrous chelate microcapsules in Examples 1-4

[0054]

[0055] Table 1 shows that the chelation rate and iron content of rice peptides with FeCl2·4H2O both increase with the increase of rice peptides. When the mass ratio of rice peptides to ferrous iron is 4:1, the chelation rate reaches a maximum of 85.5%, and the iron content is 11.42%. Further increasing the mass of rice peptides does not significantly change the ferrous ion chelation rate. Through a coupled process of "ultrasonic-enzymatic hydrolysis" pretreatment of the wall material solution and pre-dispersion of the core material, the encapsulation rate of rice peptide iron chelate to wall material at a mass ratio of 1:3 is also as high as 89.6%. Compared with other composite wall materials and core materials where the hydrophobicity of rice peptides differs greatly, easily forming defects such as "interfacial incompatibility, loose network, and poor stability," homologous peptides have more consistent amino acid composition and hydrophobicity, and will not generate interfacial voids due to "intermolecular repulsion" when mixed with the core material. Therefore, using homologous high molecular weight rice peptides to encapsulate low molecular weight rice peptide ferrous chelates results in better encapsulation rate and stability.

[0056] Depend on Figure 1 It can be seen that the rice polypeptide ferrous chelate microcapsules are very stable during 6 months of storage. The release of free iron from the unmicroencapsulated rice polypeptide chelate is 4.07%, while the release of free iron from the microencapsulated rice polypeptide ferrous chelate is only 0.51%. Figure 2 It was found that the ferrous ion release rate of rice polypeptide ferrous chelate microcapsules after digestion by gastric and intestinal juices was lower than that of rice polypeptide ferrous chelate and FeCl2·4H2O. This indicates that the homologous synergistic system formed by high molecular weight rice polypeptides as wall materials encapsulating low molecular weight rice polypeptide ferrous chelates increases the stability of the chelation. This makes the chelate structure less susceptible to destruction by pepsin in gastric juice and also relatively stable in intestinal juice, thus improving the bioavailability of the product.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions also fall within the protection scope defined by the appended claims.

Claims

1. A method for preparing rice polypeptide ferrous chelate microcapsules, comprising the following steps: Step S1, Preparation of rice peptides: Dissolve the raw rice protein in deionized water to prepare a 10% (w / w) solution. Add protease in a certain proportion, adjust the pH, and react at a certain temperature for a period of time to obtain rice protein hydrolysate. Separate the obtained hydrolysate through an ultrafiltration membrane, collect the filtrates corresponding to small molecular weight rice peptides with a molecular weight less than 3000 Da and large molecular weight rice peptides with a molecular weight greater than 3000 Da, and freeze-dry them. Step S2, Preparation of rice polypeptide ferrous chelate: Dissolve the low molecular weight rice polypeptide obtained in S1 in deionized water to prepare a 10% (w / w) solution. Add inorganic ferrous salt in a certain proportion, adjust the pH, and react at a certain temperature for a period of time to obtain a rice polypeptide ferrous chelate solution. Wash with a certain proportion of 95% ethanol, centrifuge to collect the precipitate, and vacuum dry to obtain the low molecular weight rice polypeptide ferrous chelate. Step S3, Microencapsulation of Rice Peptide Ferrous Chelate: The high molecular weight rice peptides obtained in S1 and yeast dextran prepared as raw materials are mixed evenly at a certain mass ratio and then added to deionized water to prepare a 10% wall material solution. The wall material solution is first ultrasonically treated, and then 0.3% transglutaminase is added. The solution is gently catalyzed at 30°C to obtain a homogeneous and stable wall material solution. The low molecular weight rice peptide ferrous chelate solution prepared in step S2 is pre-dispersed into nano-sized droplets using a microfluidic homogenizer and then slowly injected into the wall material solution. The solution is continuously stirred for 10-40 min using a high-speed stirrer. The emulsion is then spray-dried to obtain rice peptide ferrous chelate microcapsules.

2. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S1, the protease is one or more of alkaline protease, neutral protease, and papain.

3. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S1, the protease is an alkaline protease with an enzyme amount of 2500-10000 U / g, a hydrolysis time of 1-4 h, a hydrolysis temperature of 40-70 ℃, and a pH value of 9-12.

4. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S1, the protease is an alkaline protease with an enzyme amount of 7500 U / g, a hydrolysis time of 2 h, a hydrolysis temperature of 60 ℃, and a pH value of 10.

5. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S2, the mass ratio of the small molecular weight rice peptides to the inorganic ferrous salt is 2:1-5:1, the reaction pH is 6-9, and the temperature is 50 ℃.

6. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S2, the mass ratio of the low molecular weight rice peptide to the inorganic ferrous salt is 4:1, the pH value is 7, the reaction time is greater than or equal to 1 h, and the temperature is 50 ℃.

7. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S3, the mass ratio of the high molecular weight rice peptide to yeast glucan is 2:1-5:1, the mass ratio of the low molecular weight rice peptide ferrous chelate to the wall material is 1:1-1:4, and the stirring time is greater than 30 minutes.

8. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S3, the mass ratio of high molecular weight rice peptides to yeast glucan is 4:1, the mass ratio of low molecular weight rice peptide ferrous chelate to wall material is 1:3, and the stirring time is greater than 30 min.

9. The method for preparing rice polypeptide ferrous chelate microcapsules according to claim 1, characterized in that: In step S3, the spray drying conditions are an inlet temperature of 150 or 160 ℃ and an outlet temperature of 80 or 90 ℃.

10. Rice polypeptide ferrous chelate microcapsules, characterized in that, It is prepared by the preparation method of any one of claims 1-9.

Images