阅读说明：本技术 一种从大米中提取大米淀粉和大米活性肽的方法 (Method for extracting rice starch and rice active peptide from rice ) 是由 宫智勇 吴永宁 张�荣 王泽宇 于 2019-12-09 设计创作，主要内容包括：本发明公开一种从大米中提取大米淀粉和大米活性肽的方法,包括以下步骤：将大米粉与水混合后,调节pH值呈碱性,然后搅拌浸提并分离上清液和沉淀物；分别对所述上清液和沉淀物进行纯化后干燥粉碎,对应制得大米蛋白粉和大米淀粉；将所述大米蛋白粉进行酶解处理后收集酶解液,得到大米粗肽提取液；对所述大米粗肽提取液进行纯化,制得大米活性肽。本发明先在碱性条件下从大米粉中分离出大米淀粉和大米蛋白粉,然后以大米蛋白粉为原料,通过酶解法制成大米肽粗提液,再对大米肽粗提液进行纯化,制得大米活性肽,工艺简便,耗时较短且提取率高,不仅提高了大米多肽的提取效率,同时还副产大米淀粉,提高了原料利用率。(The invention discloses a method for extracting rice starch and rice active peptide from rice, which comprises the following steps: mixing rice flour with water, adjusting pH to alkaline, stirring, leaching, and separating supernatant and precipitate; purifying the supernatant and the precipitate respectively, drying and crushing to obtain rice protein powder and rice starch correspondingly; carrying out enzymolysis treatment on the rice protein powder, and collecting enzymolysis liquid to obtain a rice crude peptide extracting solution; and purifying the rice crude peptide extracting solution to prepare the rice active peptide. According to the invention, rice starch and rice protein powder are separated from rice flour under an alkaline condition, then the rice protein powder is taken as a raw material to prepare a rice peptide crude extract through an enzymolysis method, and then the rice peptide crude extract is purified to prepare the rice active peptide.)

1. A method for extracting rice starch and rice active peptide from rice is characterized by comprising the following steps:

mixing rice flour with water, adjusting pH to alkaline, stirring, leaching, and separating supernatant and precipitate;

purifying the supernatant and the precipitate respectively, drying and crushing to obtain rice protein powder and rice starch correspondingly;

carrying out enzymolysis treatment on the rice protein powder, and collecting enzymolysis liquid to obtain a rice crude peptide extracting solution;

and purifying the rice crude peptide extracting solution to prepare the rice active peptide.

2. The method of extracting rice starch and rice bioactive peptides from rice as claimed in claim 1, wherein the step of mixing rice flour with water, adjusting the pH to alkaline, and then performing agitation leaching and separating the supernatant and precipitate comprises:

mixing rice flour with water, adding NaOH solution to adjust the pH value to 10.5-11.5, stirring and leaching at 45-55 ℃ for 3-5 hours, separating and correspondingly collecting supernate and precipitate.

3. The method for extracting rice starch and rice bioactive peptide from rice as claimed in claim 2, wherein the steps of mixing rice flour with water, adding NaOH solution to adjust pH to 10.5-11.5, then leaching at 45-55 ℃ for 3-5 h with stirring, separating and collecting supernatant and precipitate correspondingly:

the feed liquid mass ratio of the rice flour to the water is 1: (5-7); and/or the presence of a gas in the gas,

the mass concentration of the NaOH solution is 0.05-0.2%; and/or the presence of a gas in the gas,

the rice flour is made from rice contaminated with cadmium.

4. The method for extracting rice starch and rice active peptide from rice as claimed in claim 1, wherein the step of drying and pulverizing the supernatant and the precipitate respectively after purifying the supernatant and the precipitate, respectively, to obtain rice protein powder and rice starch, comprises:

adjusting the pH value of the supernatant to 4.0-5.5, separating out solid precipitate, washing, freeze-drying and crushing to obtain rice protein powder;

after washing the precipitate, yellow solid matter was removed therefrom, followed by drying and pulverization to obtain rice starch.

5. The method for extracting rice starch and rice active peptide from rice as claimed in claim 1, wherein the step of collecting enzymolysis liquid after performing enzymolysis treatment on the rice protein powder to obtain rice crude peptide extract comprises:

preparing the rice protein powder into rice protein suspension, adding alkaline protease into the rice protein suspension, and carrying out first enzymolysis under the stirring action to obtain a first enzymolysis product;

adding trypsin into the first enzymolysis product for carrying out second enzymolysis, inactivating enzyme after the enzymolysis is finished, separating and collecting supernatant to obtain enzymolysis liquid, namely the rice crude peptide extracting solution.

6. The method for extracting rice starch and rice active peptide from rice as claimed in claim 5, wherein the step of preparing the rice protein powder into a rice protein suspension, adding alkaline protease into the rice protein suspension, and performing a first enzymolysis under stirring to obtain a first enzymolysis product comprises:

in the rice protein suspension, the mass concentration of the rice protein powder is 7-8%; and/or the presence of a gas in the gas,

the addition amount of the alkaline protease is 1.5-2.5% of the weight of the rice protein powder; and/or the presence of a gas in the gas,

the pH value of enzymolysis of the first enzymolysis is 8.5-9.5, the enzymolysis temperature is 53-57 ℃, and the enzymolysis time is 110-130 min.

7. The method for extracting rice starch and rice active peptide from rice as claimed in claim 5, wherein the step of adding trypsin to the first enzymolysis product for the second enzymolysis, inactivating enzyme after the enzymolysis is finished, separating and collecting supernatant to obtain enzymolysis liquid, namely the rice crude peptide extract:

the adding amount of the trypsin is 1.5-2.5% of the weight of the rice protein powder; and/or the presence of a gas in the gas,

the pH value of enzymolysis of the second enzymolysis is 7.0-8.0, the enzymolysis temperature is 35-40 ℃, and the enzymolysis time is 20-40 min.

8. The method for extracting rice starch and rice bioactive peptides from rice as claimed in claim 1, wherein the step of purifying the extract of rice crude peptides to obtain rice bioactive peptides comprises:

diluting the rice crude peptide extracting solution, performing ultrafiltration by using an ultrafiltration membrane, collecting a penetrating fluid, and freeze-drying to obtain small molecular peptides;

dissolving small molecular peptide in water to prepare a peptide solution, injecting the peptide solution into a chromatographic column, rinsing the chromatographic column by using ultrapure water, eluting the chromatographic column by using ethanol, collecting eluent, and performing vacuum freeze drying to prepare the rice active peptide.

9. The method for extracting rice starch and rice active peptide from rice as claimed in claim 8, wherein the step of diluting the rice crude peptide extract, performing ultrafiltration using an ultrafiltration membrane, collecting the permeate and freeze-drying to obtain small molecular peptide comprises:

the molecular weight cut-off of the ultrafiltration membrane is 3000, and the operating pressure of ultrafiltration is 0.05-0.2 MPa.

10. The method for extracting rice starch and rice active peptides from rice as claimed in claim 8, wherein the step of preparing the rice active peptides comprises dissolving the small molecular peptides in water to prepare a peptide solution, injecting the peptide solution into a chromatographic column, rinsing the chromatographic column with ultra pure water, eluting the chromatographic column with ethanol, collecting the eluate, and vacuum freeze-drying the eluate:

the mass concentration of the small molecular peptide in the peptide solution is 8-12 mg/mL; and/or the presence of a gas in the gas,

the type of the adsorption resin in the chromatographic column is DA 201-C.

Technical Field

The invention relates to the technical field of food processing, in particular to a method for extracting rice starch and rice active peptide from rice.

Background

Disclosure of Invention

The invention mainly aims to provide a method for extracting rice starch and rice active peptide from rice, aiming at improving the preparation efficiency of rice polypeptide.

In order to achieve the purpose, the invention provides a method for extracting rice starch and rice active peptide from rice, which comprises the following steps:

mixing rice flour with water, adjusting pH to alkaline, stirring, leaching, and separating supernatant and precipitate;

purifying the supernatant and the precipitate respectively, drying and crushing to obtain rice protein powder and rice starch correspondingly;

carrying out enzymolysis treatment on the rice protein powder, and collecting enzymolysis liquid to obtain a rice crude peptide extracting solution;

and purifying the rice crude peptide extracting solution to prepare the rice active peptide.

Alternatively, the step of mixing rice flour with water, adjusting the pH to alkaline, and then performing agitation leaching and separating the supernatant and precipitate comprises:

mixing rice flour with water, adding NaOH solution to adjust the pH value to 10.5-11.5, stirring and leaching at 45-55 ℃ for 3-5 hours, separating and correspondingly collecting supernate and precipitate.

Optionally, after mixing the rice flour with water, adding a NaOH solution to adjust the pH value to 10.5-11.5, then stirring and leaching at 45-55 ℃ for 3-5 hours, and then separating and correspondingly collecting the supernatant and the precipitate:

the feed liquid mass ratio of the rice flour to the water is 1: (5-7); and/or the presence of a gas in the gas,

the mass concentration of the NaOH solution is 0.05-0.2%; and/or the presence of a gas in the gas,

the rice flour is made from rice contaminated with cadmium.

Optionally, the step of purifying, drying and crushing the supernatant and the precipitate respectively to obtain rice protein powder and rice starch correspondingly comprises:

adjusting the pH value of the supernatant to 4.0-5.5, separating out solid precipitate, washing, freeze-drying and crushing to obtain rice protein powder;

after washing the precipitate, yellow solid matter was removed therefrom, followed by drying and pulverization to obtain rice starch.

Optionally, the step of collecting an enzymolysis solution after carrying out enzymolysis treatment on the rice protein powder to obtain a rice crude peptide extract comprises the following steps:

preparing the rice protein powder into rice protein suspension, adding alkaline protease into the rice protein suspension, and carrying out first enzymolysis under the stirring action to obtain a first enzymolysis product;

adding trypsin into the first enzymolysis product for carrying out second enzymolysis, inactivating enzyme after the enzymolysis is finished, separating and collecting supernatant to obtain enzymolysis liquid, namely the rice crude peptide extracting solution.

Optionally, the rice protein powder is prepared into rice protein suspension, alkaline protease is added into the rice protein suspension, and first enzymolysis is carried out under the stirring action to obtain a first enzymolysis product:

in the rice protein suspension, the mass concentration of the rice protein powder is 7-8%; and/or the presence of a gas in the gas,

the addition amount of the alkaline protease is 1.5-2.5% of the weight of the rice protein powder; and/or the presence of a gas in the gas,

the pH value of enzymolysis of the first enzymolysis is 8.5-9.5, the enzymolysis temperature is 53-57 ℃, and the enzymolysis time is 110-130 min.

Optionally, adding trypsin into the first enzymolysis product to carry out second enzymolysis, inactivating enzyme after the enzymolysis is finished, separating and collecting supernatant to obtain enzymolysis liquid, namely the rice crude peptide extracting solution:

the adding amount of the trypsin is 1.5-2.5% of the weight of the rice protein powder; and/or the presence of a gas in the gas,

the pH value of enzymolysis of the second enzymolysis is 7.0-8.0, the enzymolysis temperature is 35-40 ℃, and the enzymolysis time is 20-40 min.

Optionally, the step of purifying the rice crude peptide extract to obtain rice active peptide comprises:

diluting the rice crude peptide extracting solution, performing ultrafiltration by using an ultrafiltration membrane, collecting a penetrating fluid, and freeze-drying to obtain small molecular peptides;

dissolving small molecular peptide in water to prepare a peptide solution, injecting the peptide solution into a chromatographic column, rinsing the chromatographic column by using ultrapure water, eluting the chromatographic column by using ethanol, collecting eluent, and performing vacuum freeze drying to prepare the rice active peptide.

Optionally, after diluting the rice crude peptide extract, performing ultrafiltration by using an ultrafiltration membrane, collecting a penetrating fluid, and performing freeze drying to obtain small molecular peptides:

the molecular weight cut-off of the ultrafiltration membrane is 3000, and the operating pressure of ultrafiltration is 0.05-0.2 MPa.

Optionally, dissolving the small molecule peptide in water to prepare a peptide solution, injecting the peptide solution into a chromatographic column, rinsing the chromatographic column with ultrapure water, eluting the chromatographic column with ethanol, collecting the eluate, and performing vacuum freeze drying to prepare the rice active peptide, wherein the peptide solution comprises the following steps:

the mass concentration of the small molecular peptide in the peptide solution is 8-12 mg/mL; and/or the presence of a gas in the gas,

the type of the adsorption resin in the chromatographic column is DA 201-C.

According to the technical scheme provided by the invention, rice starch and rice protein powder are separated from rice flour under an alkaline condition, then the rice protein powder is used as a raw material to prepare a rice peptide crude extract through an enzymatic hydrolysis method, and then the rice peptide crude extract is purified to prepare the rice active peptide.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart of an embodiment of the method for extracting rice starch and rice active peptide from rice according to the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a method for extracting rice starch and rice active peptide from rice, and figure 1 shows an embodiment of the method for extracting rice starch and rice active peptide from rice provided by the invention. Referring to fig. 1, in this embodiment, the method for extracting rice starch and rice active peptide from rice includes the following steps:

step S10, mixing rice flour with water, adjusting the pH value to be alkaline, then stirring and leaching, and separating supernatant and precipitate;

mixing rice flour with water, adding NaOH solution to adjust the pH value to 10.5-11.5, then using a magnetic stirrer to stir and leach for 3-5 hours at the temperature of 45-55 ℃, then separating and correspondingly collecting supernatant and precipitate, wherein the separation mode can be a filtration mode or a centrifugation mode, taking centrifugation as an example (all solid-liquid separation related modes in the text take centrifugation treatment as an example), the separation mode can be centrifugation for 20 minutes at the rotating speed of 4000r/min, the separated supernatant is rice protein extracting solution, and the precipitate is crude starch.

Further, in step S10, the feed-liquid mass ratio of the rice flour to the water is 1: (5-7), the rice protein can be effectively extracted, and excessive waste water can be avoided. The mass concentration of the NaOH solution is 0.05-0.2%, the pH value of the rice flour solution can be quickly adjusted, and the problem that the potential operation hazard exists due to the fact that the concentration of the NaOH solution is too high is solved. The method provided by the embodiment of the invention is not only suitable for all rice raw materials, but also suitable for rice polluted by cadmium, can effectively extract rice starch and rice polypeptide from the rice polluted by cadmium, and can reduce the cadmium content to be within an edible safety range in the extraction process, so that the rice polluted by cadmium can be effectively utilized.

Step S20, purifying the supernatant and the precipitate respectively, drying and crushing to obtain rice protein powder and rice starch correspondingly;

in the present embodiment, step S20 includes:

s21, adjusting the pH value of the supernatant to 4.0-5.5, separating out solid precipitates, washing, freeze-drying and crushing to obtain rice protein powder;

and adjusting the pH value of the supernatant to 4.0-5.5, carrying out acid reduction, then centrifuging at 4000r/min for 20-30 min, washing with water and precipitating for 3 times to obtain rice protein, freeze-drying and crushing the rice protein to obtain rice protein powder, and storing the rice protein powder in a dryer for later use.

And step S22, washing the precipitate, removing yellow solid matters in the precipitate, and then drying and crushing the precipitate to obtain the rice starch.

Washing the precipitate with water for 3 times, carefully removing yellow powder to obtain rice starch, drying in oven, pulverizing to obtain rice starch, and storing in dryer for use.

Step S30, carrying out enzymolysis treatment on the rice protein powder, and collecting enzymolysis liquid to obtain a rice crude peptide extracting solution;

in the present embodiment, step S30 includes:

step S31, preparing the rice protein powder into rice protein suspension, adding alkaline protease into the rice protein suspension, and carrying out first enzymolysis under the stirring action to obtain a first enzymolysis product;

weighing a certain amount of prepared rice protein powder, and mixing the rice protein powder with water according to the proportion of 7-8% of protein mass concentration to prepare rice protein suspension; then adding alkaline protease into the rice protein suspension, wherein the enzyme adding amount is 1.5-2.5% of the mass of the rice protein; and adjusting the pH value to 8.5-9.5, and stirring and performing enzymolysis at the temperature of 53-57 ℃ for 110-130 min to obtain a first enzymolysis product.

And step S32, adding trypsin into the first enzymolysis product for carrying out second enzymolysis, inactivating enzyme after the enzymolysis is finished, separating and collecting supernate to obtain enzymolysis liquid, namely the rice crude peptide extracting solution.

Adding trypsin into a product obtained by the first enzymolysis, wherein the enzyme adding amount is 1.5-2.5% of the weight of the rice protein powder; then adjusting the pH value to 7.0-8.0, and stirring and performing enzymolysis for 20-40 min at the temperature of 35-40 ℃; and after the enzymolysis is finished, adjusting the pH value to 4.0-5.0 to inactivate enzyme, centrifuging the enzymolysis product for 10-15 min at 4000r/min, and separating to obtain supernatant which is the enzymolysis liquid finally needed, namely the rice peptide crude extract.

And step S40, purifying the rice crude peptide extracting solution to obtain the rice active peptide.

In the present embodiment, step S40 includes:

step S41, diluting the rice crude peptide extracting solution, performing ultrafiltration by using an ultrafiltration membrane, collecting a penetrating fluid, and freeze-drying to obtain small molecular peptides;

diluting the obtained rice peptide crude extract to 2.0L with water, performing ultrafiltration at room temperature through a polysulfone roll-type ultrafiltration membrane with the molecular weight cutoff of 3000 at a certain flow rate, wherein the operating pressure is 0.05-0.2 MPa, obtaining a penetrating fluid (small molecular peptide) with the relative molecular weight of less than 3000 and a concentrated solution (large molecular peptide) with the relative molecular weight of more than 3000, and freeze-drying the penetrating fluid to obtain the small molecular peptide.

And step S42, dissolving the small molecular peptides in water to prepare a peptide solution, injecting the peptide solution into a chromatographic column, rinsing the chromatographic column by using ultrapure water, eluting the chromatographic column by using ethanol, collecting the eluent, and performing vacuum freeze drying to prepare the rice active peptide.

Desalting and purifying the small molecular peptide obtained after ultrafiltration: dissolving dried small molecular peptide in water to prepare a peptide solution with the mass concentration of the small molecular peptide of 8-12 mg/mL, injecting the peptide solution into a chromatographic column at room temperature, wherein the chromatographic column is a 3.5cm × 50cm glass chromatographic column, the treated DA201-C resin is filled in the chromatographic column, the injection flow rate is 0.5-0.6 mL/min, detecting A220nm (absorbance at 220 nm) of an effluent by using an ultraviolet detector, and stopping sampling by using A220 nm-0.05 as a transmission point; then, eluting the chromatographic column by using ultrapure water at the flow rate of 0.5-0.6 mL/min, and stopping elution when the conductivity of the eluent is detected to be basically consistent with that of the ultrapure water; and then eluting the chromatographic column by using 75% ethanol at the flow rate of 0.5-0.6 mL/min, taking ultraviolet detection A220nm of the eluent as an elution end point, collecting the eluent, performing rotary evaporation to remove the ethanol, concentrating, and finally performing vacuum freeze drying to obtain the purified rice active peptide.

According to the technical scheme provided by the invention, rice starch and rice protein powder are separated from rice flour under an alkaline condition, then the rice protein powder is taken as a raw material, a rice peptide crude extract is prepared by an enzymolysis method, and then the rice peptide crude extract is purified to prepare the rice active peptide, so that the process is simple, the consumed time is short, the extraction rate is high, the extraction efficiency of rice polypeptide is improved, and meanwhile, the byproduct rice starch is also produced, and the utilization rate of the raw material is improved; but also can be suitable for extracting rice starch and rice active peptide from the rice polluted by cadmium, thereby improving the utilization value of the rice polluted by cadmium.

The technical solutions of the present invention are further described in detail below with reference to specific examples and drawings, it should be understood that the following examples are merely illustrative of the present invention and are not intended to limit the present invention.