阅读说明：本技术 一种利用单宁酸提高玉米黄粉蛋白酶解速率的方法 (Method for improving proteolysis rate of corn gluten meal by using tannic acid ) 是由 肖志刚 柴媛 高育哲 段玉敏 王依凡 王可心 王娜 朱旻鹏 段庆松 于 2019-12-04 设计创作，主要内容包括：本发明公开了一种利用单宁酸提高挤压玉米黄粉蛋白酶解速率的方法。该方法以玉米黄粉蛋白为原料,使用双螺杆挤压机将玉米黄粉蛋白挤压处理,烘干粉碎后过筛获得挤压玉米黄粉蛋白,经过单宁酸处理后,采用碱性蛋白酶、胰蛋白酶进行双酶法酶解处理,沸水浴灭酶后得到单宁酸-挤压玉米黄粉蛋白多肽。单宁酸的疏水基团没食子酰基和蛋白多肽链上的某些疏水基团由于避开水而黏附聚集在一起,蛋白表面疏水性随单宁酸含量的增大而降低,内部疏水作用增强,从而一定量的增大了蛋白上清溶液中的可溶性蛋白含量,较大程度地解决了玉米蛋白粉疏水性强、溶解度不高、酶解率低的问题,提高了玉米黄粉蛋白的生物利用率。(The invention discloses a method for improving the proteolysis rate of extruded corn gluten meal by using tannic acid. The method comprises the steps of taking corn gluten protein as a raw material, extruding the corn gluten protein by using a double-screw extruder, drying, crushing, sieving to obtain extruded corn gluten protein, treating with tannic acid, performing double-enzyme enzymolysis by using alkaline protease and trypsin, and inactivating enzyme in a boiling water bath to obtain the tannic acid-extruded corn gluten protein polypeptide. The hydrophobic galloyl group of the tannic acid and certain hydrophobic groups on the protein polypeptide chain are adhered and aggregated together due to water avoidance, the surface hydrophobicity of the protein is reduced along with the increase of the content of the tannic acid, and the internal hydrophobic effect is enhanced, so that the content of soluble protein in the protein supernatant is increased by a certain amount, the problems of strong hydrophobicity, low solubility and low enzymolysis rate of the corn gluten meal are solved to a great extent, and the bioavailability of the corn gluten meal protein is improved.)

1. A method for improving the proteolysis rate of corn gluten meal by using tannic acid is characterized by comprising the following steps: extruding the corn gluten meal protein powder by a double-screw extruder, drying, crushing, sieving, adding tannic acid to prepare a corn gluten meal/tannic acid composite solution, and freeze-drying and storing; and (3) preparing the freeze-dried powder into a suspension with a certain concentration, carrying out double-enzyme enzymolysis by using alkaline protease and trypsin, and inactivating enzymes in boiling water bath to obtain the tannin-extruded maize yellow powder protein polypeptide.

2. The method for improving the proteolysis rate of the maize yellow powder by using the tannic acid as claimed in claim 1, wherein the maize yellow powder protein powder is quantitatively added into a double-screw extruder through a feeder, the machine is a three-section temperature-controlled co-rotating or counter-rotating double-screw extruder with the length-diameter ratio of 16-26:1, the working temperature of each section cavity of the double-screw extruder is set as follows: the temperature of the first zone is 30-50 ℃, the temperature of the second zone is 50-70 ℃, the temperature of the third zone is 70-80 ℃, the screw rotation speed is 180-300 r/min, the solid feeding amount is 15-25 kg/h, the water content of the material is 15-20%, the extruded maize yellow powder protein is dried in an oven at 40-50 ℃ for 24h, and the extruded maize yellow powder protein is crushed and sieved by a 100-200-mesh sieve, so that the extruded maize yellow powder protein powder is obtained.

3. The method as claimed in claim 1, wherein the method comprises dissolving 5g of the extruded zein powder in 50mL of ultrapure water, shaking for two hours, mixing, and filtering the supernatant with Whatman No.4 filter paper.

4. The method as claimed in claim 1, wherein the mass ratio of the extruded zeaxanthin protein to the tannin is 50:1, wherein the mass concentration of the extruded zeaxanthin in the zeaxanthin/tannin complex solution is 10%, and the extruded zeaxanthin is uniformly mixed by shaking at random for two hours.

5. The method for improving the proteolysis rate of corn gluten meal by using tannic acid as claimed in claim 1, wherein the proteolysis specifically comprises the following steps:

(1) and (3) alkaline protease treatment: preparing tannin-extruded maize yellow powder protein into 8-10% protein suspension, adjusting the temperature of a water bath to 45-55 ℃, adjusting the pH to 7.5-8, adding 1-2% of enzyme, performing enzymolysis for 90min, then inactivating the enzyme in 80 ℃ water for 10-20min, cooling to room temperature, centrifuging for 15min at 4000 Xg, collecting supernatant, and freeze-drying.

(2) And (3) trypsin treatment: preparing 8-10% tannin-extruded corn gluten meal suspension, adjusting the temperature of a water bath to 35-45 ℃, adjusting the pH to 7.8-8.5, adding 1-2% of enzyme, performing enzymolysis for 90min, then inactivating the enzyme in 90 ℃ water for 10-20min, cooling to room temperature, centrifuging for 15min at 4000 Xg, collecting supernatant, and freeze-drying to obtain the tannin-extruded corn gluten meal protein polypeptide.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to a method for improving the proteolysis rate of corn gluten meal by using tannic acid.

Background

The corn gluten meal is a byproduct generated in the process of industrially preparing corn starch by a wet milling method, and is a plant protein resource with huge yield and low price. Due to the difference of low technical level of starch processing enterprises, the content of protein in the corn gluten meal is usually between 50 and 60 percent, and the corn protein is mainly used in the animal feed industry and is less used in the flour product processing industry, which also causes the situation that the corn protein is low-valued for a long time to a certain extent. However, the main component of the maize yellow powder is prolamin, and the maize yellow powder also contains a small amount of glutelin, globulin, albumin and the like, and has the defects of poor water solubility, low bioavailability, low nutritional value and the like.

The extrusion puffing technology is a new technology in food processing. Under the low hydration state, the raw materials are subjected to the combined action of high temperature, high pressure and high shear in the extruder, so that the tightly and orderly combined state of starch and protein in the corn gluten meal is converted into a loose and disordered structure, the spatial position is reduced, the sensitivity of the corn gluten meal to protease is increased, and the digestibility of the protein is improved. Meanwhile, hydrogen bonds among starch chains are broken, starch grains are substituted, and peptide chains are exposed, so that the action process of enzyme preparations and microorganisms can be accelerated, and the utilization rate of raw materials is improved. Therefore, through proper protein denaturation treatment, the secondary and tertiary structures of the protein are destroyed, certain genes in the zein molecule are exposed on the surface of the molecule, and the hydrolysis effect of the zein can be enhanced.

Tannins are a group of natural products which are usually present in barley, sorghum, mung bean, grape, tea, pomegranate, persimmon, etc. in the form of free acids or various esters. The phenolic hydroxyl group contained in the structure of the tannic acid is a polar group, and the galloyl group is a hydrophobic group, so that the galloyl group of the tannic acid is supposed to be combined with the hydrophobic group of the corn protein through hydrophobic effect, and the phenolic hydroxyl group of the tannic acid can be combined with the polar group in the corn protein in a hydrogen bond mode in multiple points, thereby influencing the processing quality of the corn.

The hydrolysis of corn protein by enzymolysis method has mild action condition, and the hydrolysate has various active ingredients, which is the hot spot of the current research. The water solubility and some functional characteristics of the zein are improved by enzyme method modification, and the method has the advantages of strong controllability, less energy consumption, strong specificity, less byproducts and the like. Due to the unique amino acid composition of zein, protease with hydrophobic amino acid residues as action sites as much as possible is adopted, and the relative hydrophobicity of the polypeptide is improved. The single enzyme has low hydrolysis capability, which is not beneficial to improving the conversion rate of the substrate, so the compound enzyme hydrolysis method is adopted.

Disclosure of Invention

The invention aims to provide a method which has low cost and simple operation method and utilizes tannic acid to obviously improve the proteolysis rate of extruded maize yellow powder.

The purpose of the invention can be realized by the following technical scheme:

a method for improving the proteolysis rate of corn gluten meal by using tannic acid comprises the following steps: extruding the corn gluten meal protein powder by a double-screw extruder, drying, crushing, sieving, adding tannic acid to prepare a corn gluten meal/tannic acid composite solution, and freeze-drying and storing; and (3) preparing the freeze-dried powder into a suspension with a certain concentration, carrying out double-enzyme enzymolysis by using alkaline protease and trypsin, and inactivating enzymes in boiling water bath to obtain the tannin-extruded maize yellow powder protein polypeptide.

Quantitatively adding the corn gluten meal into a double-screw extruder through a feeder, wherein the extruder is a three-section temperature-control co-rotating or counter-rotating double-screw extruder with the length-diameter ratio of 16-26:1, and the working temperature of each section cavity of the double-screw extruder is set as follows: the temperature of the first zone is 30-50 ℃, the temperature of the second zone is 50-70 ℃, the temperature of the third zone is 70-80 ℃, the screw rotation speed is 180-300 r/min, the solid feeding amount is 15-25 kg/h, the water content of the material is 15-20%, the extruded maize yellow powder protein is dried in an oven at 40-50 ℃ for 24h, and the extruded maize yellow powder protein is crushed and sieved by a 100-200-mesh sieve, so that the extruded maize yellow powder protein powder is obtained.

5g of extruded corn gluten meal is dissolved in 50mL of ultrapure water, the mixture is continuously shaken and mixed evenly within two hours, and the supernatant passes through Whatman No.4 filter paper.

The mass ratio of the extruded maize yellow meal protein to the tannin is 50:1, wherein the mass concentration of the extruded maize yellow meal protein in the maize yellow meal protein/tannin composite solution is 10%, and the extruded maize yellow meal protein and the tannin composite solution are uniformly mixed by shaking at variable times within two hours.

The enzymolysis specifically comprises the following steps:

(1) and (3) alkaline protease treatment: preparing tannin-extruded maize yellow powder protein into 8-10% protein suspension, adjusting the temperature of a water bath to 45-55 ℃, adjusting the pH to 7.5-8, adding 1-2% of enzyme, performing enzymolysis for 90min, then inactivating the enzyme in 80 ℃ water for 10-20min, cooling to room temperature, centrifuging for 15min at 4000 Xg, collecting supernatant, and freeze-drying.

(2) And (3) trypsin treatment: preparing 8-10% tannin-extruded corn gluten meal suspension, adjusting the temperature of a water bath to 35-45 ℃, adjusting the pH to 7.8-8.5, adding 1-2% of enzyme, performing enzymolysis for 90min, then inactivating the enzyme in 90 ℃ water for 10-20min, cooling to room temperature, centrifuging for 15min at 4000 Xg, collecting supernatant, and freeze-drying to obtain the tannin-extruded corn gluten meal protein polypeptide.

The invention has the beneficial effects that:

the method comprises the steps of extruding the maize yellow powder protein by using a double-screw extruder, drying and crushing the maize yellow powder protein, sieving the dried maize yellow powder protein by using a 100-200 sieve to obtain the extruded maize yellow powder protein, treating the extruded maize yellow powder protein by tannic acid, performing double-enzyme enzymolysis by using alkaline protease and trypsin, and inactivating the enzyme in a boiling water bath to obtain the tannic acid-extruded maize yellow powder protein polypeptide. The invention takes the maize yellow meal protein as the raw material, has the characteristics of low cost, convenient operation and the like, solves the problems of strong hydrophobicity, low solubility and low enzymolysis rate of the maize protein powder to a great extent, and improves the bioavailability of the maize yellow meal protein.

Detailed Description