A method for processing and producing selenium-rich wheat flour

Abstract

This invention belongs to the field of wheat processing technology, and particularly relates to a method for processing and producing selenium-enriched wheat flour. The method includes the following steps: S1, cleaning, removing impurities, conditioning, grinding, and sieving wheat raw materials to obtain basic wheat flour, and simultaneously collecting protein-rich intermediate materials generated during wheat starch production; S2, preparing a protein-rich liquid with a protein dry basis mass concentration of 10-20% from the protein-rich intermediate material; S3, using the protein-rich liquid as a matrix, reacting it with an organic selenium source, and then subjecting it to cross-linking, curing, drying, and micronization to obtain selenium-enriched powder; S4, mixing the selenium-enriched powder with the basic wheat flour to obtain selenium-enriched wheat flour. This invention improves the water solubility of the organic selenium source by cross-linking and curing it within wheat protein, thereby achieving a retention rate of over 94% of the organic selenium source during cooking.

Description

Technical Field

[0001] This invention belongs to the field of wheat processing technology, and in particular relates to a method for processing and producing selenium-enriched wheat flour. Background Technology

[0002] Selenium is an essential trace element for the human body, playing a vital role in maintaining immune system function and antioxidation. Supplementing selenium through diet is a safe and effective method, with selenium-enriched wheat flour being one of the ideal carriers.

[0003] Currently, the production of selenium-enriched wheat flour is mainly achieved through the following methods: First, agricultural fortification methods, in which selenium fertilizer is applied during the wheat planting stage, and the plant absorbs and converts it into organic selenium; second, inorganic or organic selenium is directly added and physically mixed in the later stage of flour processing.

[0004] However, these existing technologies all have significant drawbacks. Agricultural fortification methods have long production cycles, and the selenium content is greatly affected by region and climate, resulting in poor stability. Furthermore, some selenium from fortified selenium-enriched wheat is retained in the bran after processing into flour, leading to waste. More importantly, whether the selenium is obtained from cultivation or added directly, a large amount is lost during cooking due to water solubility, with loss rates generally reaching 30%-60%. This results in a serious discrepancy between the labeled selenium content and the actual effective selenium content available for human consumption, greatly limiting the nutritional value of selenium-enriched wheat flour. Summary of the Invention

[0005] The purpose of this invention is to provide a method for processing and producing selenium-enriched wheat flour to solve the problems existing in the prior art.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A method for processing selenium-enriched wheat flour includes the following steps:

[0008] S1. After cleaning, removing impurities, conditioning, grinding and sieving wheat raw materials, basic wheat flour is obtained, and protein-rich intermediate materials generated during the wheat starch production process are collected simultaneously.

[0009] S2. Prepare a protein-rich solution with a protein dry basis mass concentration of 10-20% from the protein-rich intermediate material.

[0010] S3. Using protein-rich liquid as a matrix, an organic selenium source is reacted and then cross-linked, cured, dried, and micronized to obtain selenium-rich powder.

[0011] S4. Mix the selenium-enriched powder with the base wheat flour to obtain selenium-enriched wheat flour.

[0012] Furthermore, in step S1, the protein-rich intermediate material is: protein-rich washing water after separating wheat starch from protein, and / or wet gluten from wheat starch production, and / or wheat gluten.

[0013] Furthermore, when the intermediate material is washing water, protein enrichment is carried out by membrane separation; when the intermediate material is wet gluten or wheat gluten, it is prepared into a protein-rich solution by dispersing it in water.

[0014] Furthermore, the specific preparation method of selenium-enriched powder is as follows: adjust the pH of the protein-enriched solution to 6.5~7.5, add an organic selenium source, stir and react at 45~55℃ for 1~3 hours, add a food-grade crosslinking agent, stir and react at 45~55℃ for 1~2 hours, and finally obtain selenium-enriched powder after drying and pulverizing.

[0015] Furthermore, the organic selenium source is an aqueous solution of L-seleno-methylselenocysteine ​​with a mass concentration of 10-20%.

[0016] Furthermore, the cross-linking agent is transglutaminase, and the amount added is 0.5~1% of the dry weight of the protein in the protein-rich solution.

[0017] Furthermore, the mass ratio of protein dry basis to organic selenium source dry basis in the protein-rich solution is 150~200:1.

[0018] The present invention has the following beneficial effects:

[0019] 1. This invention cross-links and solidifies an organic selenium source in wheat protein, thereby encapsulating and protecting the organic selenium source through these wheat proteins, thus improving its water solubility. During the cooking process, the retention rate of the organic selenium source is as high as 94% or more.

[0020] 2. The wheat protein used is a byproduct or low-value intermediate material in the production of wheat starch, such as washing water, thereby increasing its economic value.

[0021] 3. Wheat protein comes from wheat itself and will not affect the properties of wheat flour. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0023] Example 1:

[0024] A method for processing selenium-enriched wheat flour includes the following steps:

[0025] S1. After cleaning, removing impurities, conditioning, grinding and sieving the wheat raw materials, basic wheat flour is obtained, and the protein-rich washing water generated during the wheat starch production process is collected simultaneously.

[0026] S2. The washing water is first filtered to remove large particulate impurities, and then filtered through an ultrafiltration membrane with a molecular weight cutoff of 10,000 Da. The retentate is concentrated to 10% (protein dry basis concentration) through membrane concentration to obtain a protein-rich solution.

[0027] S3. Take 10 kg of protein-rich solution and add it to the reaction vessel, adjusting the pH to 6.5. Prepare a 20% aqueous solution of 6.7 g of L-seleno-methylselenocysteine ​​powder, and slowly add it to the reaction vessel with stirring. After reacting at 45°C for 3 hours, add 10 g of transglutaminase and continue reacting at 45°C for 2 hours. Finally, obtain selenium-rich powder after spray drying and pulverization.

[0028] S4. Mix 1g of selenium-enriched powder with 10.56kg of basic wheat flour to obtain selenium-enriched wheat flour with a selenium content of 0.25mg / kg.

[0029] Example 2:

[0030] This embodiment provides a comparative experiment between the selenium-enriched wheat flour of the present invention and the prior art.

[0031] Comparative Sample 1: Selenium-enriched wheat grown with sodium selenite nutrient solution through foliar spraying was used to prepare selenium-enriched wheat flour using conventional processes, with a total selenium content of 0.25 mg / kg. 500g of this flour was then processed into fresh, wet noodles using conventional processes.

[0032] Comparative Sample 2: Take 500g of ordinary basic wheat flour, add L-seleno-methylselenocysteine ​​powder directly, and prepare selenium-enriched wheat flour with a total selenium content of 0.25mg / kg using a dry powder mixer, and then make fresh wet noodles using the same process.

[0033] Test sample 1: Take 500g of selenium-enriched wheat flour obtained in Example 1 and make it into fresh wet noodles using the same process.

[0034] Accurately weigh 50.0g of each fresh wet noodle sample and place it in a pot containing 500mL of boiling water. Cook at a gentle simmer for 5 minutes. After cooking, immediately remove the noodles and let them drain for 2 minutes. Collect the cooked noodles and the broth separately, and determine the total selenium content in all the cooked noodles and broth. Each sample was measured in triplicate, and the average value was taken. Calculation:

[0035] Selenium retention rate of noodles (%) = (Selenium content of noodles after cooking / Selenium content of noodles before cooking) × 100%;

[0036] Selenium leaching rate in noodle soup (%) = (Total selenium in noodle soup / Total selenium in cooked noodles) × 100%.

[0037] The results are shown in Table 1 below:

[0038] Table 1: Experimental Results

[0039] Sample number Selenium content of noodles before cooking (mg / kg) Selenium content (mg / kg) of noodles after cooking Selenium retention rate of noodles (%) Selenium dissolution rate in noodle soup (%) Comparison Sample 1 0.25 0.188 75.2 22.5 Comparison Sample 2 0.25 0.18 72 26.4 Test sample 1 0.25 0.236 94.4 4.4

[0040] As shown in Table 1, compared to Sample 1, which was made from non-exogenous selenium-enriched wheat flour, the selenium retention rate of noodles was only 75.2%, with nearly a quarter dissolving. Sample 2, made from exogenous selenium-enriched wheat flour, had an even lower selenium retention rate. This is because the exogenously added organic selenium source had a weaker bond with the gluten network, making it easily soluble in boiling water. Samples 1-3 were all noodles made from the selenium-enriched wheat flour of this invention. Because the organic selenium source was firmly fixed to the wheat protein network structure through covalent cross-linking with transglutaminase, the retention rate was all above 94%, thus greatly reducing the dissolution of selenium during cooking.

[0041] This invention does not directly add organic selenium sources to flour. Instead, it first utilizes natural byproducts from wheat starch processing, such as wet gluten, protein wash water, or wheat gluten, to adsorb the organic selenium source, all of which contain a large amount of wheat protein. These wheat proteins adsorb the organic selenium source into their protein networks through hydrophobic interactions, hydrogen bonds, and electrostatic attraction. Subsequently, cross-linking by transglutaminase immobilizes the organic selenium source onto the protein backbone. Further drying further strengthens the bond between the organic selenium source and the protein, thus encapsulating and protecting the organic selenium source through these wheat proteins, thereby improving its resistance to water solubility.

[0042] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention should fall within the protection scope of the present invention.

[0043] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A method for processing and producing selenium-enriched wheat flour, characterized in that, Includes the following steps: S1. After cleaning, removing impurities, conditioning, grinding and sieving wheat raw materials, basic wheat flour is obtained, and protein-rich intermediate materials generated during the wheat starch production process are collected simultaneously. S2. Prepare a protein-rich solution with a protein dry basis mass concentration of 10-20% from the protein-rich intermediate material. S3. Using protein-rich liquid as a matrix, an organic selenium source is reacted and then cross-linked, cured, dried, and micronized to obtain selenium-rich powder. S4. Mix the selenium-enriched powder with the base wheat flour to obtain selenium-enriched wheat flour; In step S1, the protein-rich intermediate material is: protein-rich washing water after separating wheat starch from protein, and / or wet gluten from wheat starch production, and / or wheat gluten. The organic selenium source is an aqueous solution of L-seleno-methylselenocysteine ​​with a mass concentration of 10-20%. The cross-linking agent used is transglutaminase, and the amount added is 0.5-1% of the dry weight of the protein in the protein-rich solution; The mass ratio of protein dry basis to organic selenium source dry basis in the protein-rich solution is 150~200:

1.

2. The processing method for selenium-enriched wheat flour according to claim 1, characterized in that, In step S2, when the intermediate material is washing water, protein enrichment is performed by membrane separation; when the intermediate material is wet gluten or wheat gluten, it is prepared into a protein-rich solution by dispersing it in water.

3. The processing method for selenium-enriched wheat flour according to claim 1, characterized in that, In step S3, the preparation method of the selenium-enriched powder is as follows: adjust the pH of the protein-enriched solution to 6.5~7.5, add an organic selenium source, stir and react at 45~55℃ for 1~3 hours, add a food-grade crosslinking agent, stir and react at 45~55℃ for 1~2 hours, and finally dry and pulverize to obtain selenium-enriched powder.