KR100503100B1 - Process for low molecular weight peptide preparation from rice bran. - Google Patents

Abstract

The present invention relates to a composition comprising a nutritionally rich natural amino acid or peptide from a rice bran, which is a by-product of rice milling, and an effective method for its preparation. The present invention is an alkali treatment to rice bran to dissolve and extract the soluble protein and then remove the insoluble material and recover the dissolved protein by precipitation using an organic acid, and then prepare a low molecular peptide by treating the plant-derived protease The final product is characterized in that the recovery through centrifugation or ultrafiltration membrane. The present inventors have developed a process for preparing a composition containing a simple and highly efficient rice bran-derived low molecular weight natural peptide, and in the future, it is possible to effectively prepare a composition containing essential amino acids or peptides naturally derived from rice bran in a large amount. In addition to the natural essential amino acids required for the production of non-essential amino acids that perform various physiological functions, such as organic acids, various low molecular useful ingredients contained in rice bran, along with low molecularized natural peptides to provide a low-cost manufacturing base The composition containing the group of natural amino acid peptides can be utilized in various food additive forms.

Description

Process for low molecular weight peptide preparation from rice bran using plant protease from rice bran

The present invention provides inexpensive and large quantities of low molecular nutrients from rice bran containing various amino acids necessary for maintaining the physiological activity of our body, especially essential amino acids suitable for children, adolescents who are in the growth stage and elderly people who require high-quality nutrition. It relates to a manufacturing method that can be.

Since essential amino acids are not produced by your body, you should consume a certain amount of food every day within the recommended daily range. However, the content of essential amino acids in the protein absorbed through the daily food is different depending on the type of food and each person has a different requirement depending on the diet pattern. Of the nutrients your body needs, protein is the most important nutrient. Of course, all nutrients are important for normal physiological activity, but protein is the most important nutrient. Proteins play a number of important roles, such as enzymes, which are catalysts for vital activity in our bodies, hormones, constituents of muscles or nervous bodies, and red blood cells that provide oxygen.

Milk, so far known as a high protein complete food, contains about 3.4% protein. About 80% is composed of a protein called casein, and the remainder is whey protein. Whey protein contains various water-soluble proteins such as lactoalbumin, lactogroburin, serum albumin and immunoprotein. Protein in milk is an important ingredient with a very high nutritional function, which is digested in the stomach and intestines as well as the biological function of each protein, providing many of the essential amino acids that we must consume. In addition, the digestibility of milk protein is known to be more than 97%, so it is known to be more digestible protein than vegetable proteins such as soybeans.

Rice bran, on the other hand, is one of the vast quantities of biomass produced by humans every year. Korea's rice production is about 7.3 million tons, of which rice production is estimated at about 580,000 tons. Currently, some of the rice bran is used for rice bran oil production, but some are used for animal feed and most of them are disposed of without special use. Rice bran is known to contain 34-52% soluble sugar, 15-20% crude fat, 11-15% crude protein, 7-11% crude fiber, 7-10% ash, and 14% starch. In particular, the protein content of rice bran is higher than that of milk protein. In particular, rice bran protein is known to be hypoallergenic than other proteins.

In particular, rice bran is rich in dietary fiber including hemicellulose and vitamins such as inositol, choline, niacin (B3), tocopherol (E), thiamine (B1) and pantothenic acid (B5). Juliano (1985a. Factors affecting nutritional properties of rice protein.Trans. Natl. Acad. Sci. Technol. (Philipp.), 7: 205-216; 1985b.Rice: chemistry and technology, 2nd ed. St Paul, MN, USA , Am.Assoc, Cereal Chem. 774 pp) and Pedersen & Eggum (1983. The influence of milling on the nutritive value of flour from cereal grains.IV.Rice.Qual.Plant.Plant Foods Hum.Nutr., 33: 267 (278) found that rice bran has a higher concentration of vitamin B compared to other areas. In particular, Bl contains 65%, B3 contains 80-85% and B2 contains 39%. Vitamin E (aka tocopherol) is reported to be present in 95% of all brown rice seeds. In particular, Asaf A. et al. Recently reported that water-soluble extracts and dietary fiber-enriched fractions of rice bran induce blood glucose lowering and lower cholesterol, LDL-cholesterol, apollpoprotein B and triglycerides. (Journal of Nutritional Biochemistry 13: 175-187, 2002).

In addition, although rice bran is known to contain excessive amounts of nutritionally rich useful ingredients, it is currently used only slightly as a medium for animal feed or mushroom cultivation, and is still used for humans such as soy and milk products. As a source of abundant protein has not been developed. The reason for this is, firstly, the complicated structural characteristics of rice bran protein. Rice bran protein contains 37% albumin, 36% globulin, 22% glutelin and 5% prolamin (Betschart et al. J. Food Sci. 42: 1088-1093, 1977). Second, rice bran protein has a very low solubility. This property is due to the strong aggregation of rice bran proteins and particularly strong disulfide bond crosslinks (Hamada, J. Protease solubilization of proteins in rice bran. Fresented at the IFT Annual Meeting, Anaheim, CA). , 1995; Abstract No. 68A-55). Third, rice bran protein contains high phytate (1.7%) concentration and fiber content (12%). Such constructs provide a very difficult point in separating and extracting protein components.

In recent years, as the national economy has developed and the national income has gradually increased, the elderly population has continued to increase, and the majority of people have shown a great interest in health. I'm going. Therefore, it is very meaningful to develop and extract nutritionally rich useful ingredients step by step from rice bran which can be supplied in nature at low price and low utilization.

Thus, the present inventors conducted a study to extract useful substances from rice bran, a by-product produced in Korea in large quantities annually, in order to manufacture a useful essential amino acid from natural inexpensively, and a useful low molecular nutrient containing essential amino acid. The manufacturing process for mass production was completed. Particular attention was paid to the fact that the nutrient-concentrated rice eyes and bran were lost to obtain white rice during the milling process. In general, brown rice is rich in nutrients such as protein, essential fatty acids, vitamins and fiber, and it is known to be good for improving young metabolism by protecting metabolism and improving intestinal function as well as constitution.

In particular, the amino acid composition studies of representative proteins in relation to the essential amino acid content of rice bran are as follows.

In the above table, rice bran protein does not show a significant difference in the composition of amino acids compared to conventional milk protein or soy protein. Rather, cysteine is superior to milk. As previously described, rice bran proteins are high in cysteine because they are aggregated through strong sulfide bonds. For that reason, it has been argued that rice bran protein enters our bodies and is low in the digestive system. In the present invention, in order to improve such a problem, in the extraction and protein manufacturing process, a process of converting a polymer protein into a low molecule having a molecular weight of 6,000 or less using a plant-derived protease is converted to a low molecular peptide in the manufacturing stage. To increase the utilization rate in the body through.

Attempts to recover proteins from rice bran in high yields have been published in several academic papers since 1969, but all have attempted to recover proteins after carbohydrases have been used to remove non-proteins. Representative carbohydrases enzymes used are cellulase, pectinase, hemicellulase and biscoenzyme L. In 1985 Richardson and Hyslod attempted to increase protein recovery using phytase (Enzymes. In Food Chemistry, Fennema, OR, Ed .; Marcel Dekker: New York, 1985; pp. 371-476) In 1999, Wang et al. et al. attempted to recover proteins by combining phytase and xylanase (J. Agric. Food Chem. 1999, 47, 411). However, some of these enzymes are relatively expensive and low-purity enzymes must be purchased and processed in large quantities through fungal or bacterial fermentation, which may pose safety concerns for the use of the final product as food. Even with these enzymes, there may be problems with solubility and recovery efficiency of the isolated protein, according to data published by Shih et al. Alpha-amylase, cellulase, and solution. Electrophoresis of water-soluble supernatants and insoluble precipitates obtained by treatment of hemicellulase with rice bran, respectively, showed that a significant amount of polymer rice bran protein was still present in the insoluble fraction regardless of which enzyme was treated. It still suggests that there is still a significant problem with recovery (Nahrung 43 (1999) Nr. 1, S. 14-18).

Like this, rice bran contains many ingredients that are beneficial to our body, and it is not properly used because the research on the efficient processing of these by-products, which can be used as healthy foods, has not been carried out if the proper manufacturing process is secured in terms of contents. It was a situation. Therefore, the present inventors have studied a method of extracting useful ingredients from a huge amount of biomass produced in farmhouses and using them as health foods. However, there was no provision for the extraction and production of proteins or peptides from rice bran, and thus the present invention was completed through manufacturing process studies.

A feature of the present invention suggests an optimal method of obtaining the maximum amount of protein extracted by alkali treatment of rice bran. In addition, the present invention proposes a method for producing a composite of a natural low molecular substance containing a protein and an organic acid by using a complex organic acid as a precipitation inducing material in the precipitation induction process of an alkali melt. In particular, the present invention used citric acid in the organic acid, citric acid is a component necessary to increase the utilization of oxygen in our body, it is known to perform the function of activating metabolism, helping energy release, and removing the debris in the body. As another organic acid, vinegar acid is used, which has an excellent function of preventing constipation in our body, inhibiting arteriosclerosis, and decomposing lactic acid to remove fatigue. As such, the present invention provides a method for preparing a composition containing a natural type low molecularized peptide derived from a huge rice bran biomass produced annually in nature.

In particular, for the production of low molecular peptides, in the present invention, by treating the plant-derived protease with respect to the precipitate-recovered extracts, it is possible to produce low molecular peptides, thereby contributing to increase the absorption rate in the body, Infants or adolescents, or elderly people with reduced digestive ability is characterized in that the intake of the natural essential amino acid peptide composition according to the present invention is easily applied.

In recent years, the inventors of the US Food and Drug Administration (FDA) or the European Agency for the Evaluation of Medicinal Product (EMEA) have shown a very sensitive and demanding response to the use of animal-derived substances. Attention was paid to the use of plant-derived protease which has no problem of transmission of disease than animal-derived protease in the manufacture of the present invention.

After all, it is an object of the present invention to provide a low molecular composition comprising a naturally occurring peptide that activates metabolism and a method for preparing the same.

Hereinafter, a composition including the peptide of the present invention and a method for preparing the same will be described in detail for each process.

Step 1: Sterilization and Emulsification

The starting material of the present invention may be brown rice or rice bran containing a portion thereof, and sterilized by steam sterilization or steam inactivation, and at the same time, a lipase which decomposes various protein degrading enzymes, inhibitors or fats contained in the raw material; By inactivating the same enzyme, a more stable stabilized rice bran can be made. In addition, this process also has the function of softening the rice bran to obtain the maximum protein extraction recovery rate in the alkali process. For example, heating at 100 ° C. for at least 6 minutes with steam inactivates the trypsin enzyme inhibitor. The operating conditions of the process is to complete the process by using an autoclave or by passing the steam at 100 ° C. for at least 20 minutes.

Second Step: Protein Extraction

In order to obtain an optimal protein extraction amount, the process adds water in the range of 30 ml to 100 ml per gram of rice bran and adjusts the pH of the solution to 10 or more, preferably 12 or more. The pH control solution can be used ammonia water (NH ₄ OH), calcium hydroxide (CaOH ₂ ), potassium hydroxide (KOH) or sodium hydroxide (NaOH) solution. Dissolution and stirring times are usually suitable within 10 minutes to 2 hours.

3rd process Insoluble substance removal process

Alkali Extraction of Rice Bran In order to maximize recovery of soluble protein from the dissolved solution, insoluble rice bran and the dissolved protein solution must be separated. To this end, this process recovers the alkaline extracting solution using a dehydrator equipped with a special filter inside. The recovered extracting solution is moved to the precipitation induction process, and the insoluble rice bran material obtained is beta-sitosterol (β-sitosterol). It is stored in a separate process for the extraction of phytosterol containing phytosterol.

4th process: sedimentation induction and recovery

In recovering the precipitate by lowering the pH of the alkaline extract solution recovered from the dehydrator, isoelectric PH precipitation of the dissolved protein is used simultaneously with precipitation using solubility difference. In order to achieve this object, the appropriate pH dropping range of the alkali extract identified by the present inventors is suitable for pH 3 to 6, and the most precipitate can be obtained within this range.

At this time, as a precipitation inducing substance or a substance for lowering pH, organic acids such as acetic acid and citric acid may be used alone or in combination. The white precipitate formed can be recovered as a precipitate by centrifugation at a gravity of 500g or more and 5 minutes or more.

Fifth Step: Plant Protease Treatment Process

The recovered precipitate is suspended in water, and the pH of the suspension is adjusted in the range of 5 to 8, followed by treatment with vegetable protease. In the mass production process, phosphate buffer can be used, and the plant protease can use papain enzyme obtained from palm stem and bromelain enzyme obtained from pineapple stem.

Step 6: Recovery of Low Molecular Peptide Substances by Ultrafiltration or Centrifugation

The low molecular weight rice bran peptide by the action of proteolytic enzymes can recover the low molecular weight peptide by using an air desert membrane or ultrafiltration membrane. The solution obtained in the previous process is separated using an ultrafiltration membrane (UF) with a membrane diameter of 50,000 to 10,000 MWCO (molecular weight cut-off) to separate the low molecular peptide material contained in the solution. The desired final product is recovered from the filtrate of the present ultrafiltration membrane. In addition, the low molecular weight peptide, the reaction product, can be recovered from the supernatant by centrifugation of the plant-derived enzyme reaction solution.

7th step: powder production and drying

As a final process in the present invention, the superfiltration from the ultrafiltration membranes or centrifugation can be recovered in powder form, typically via spray dry.

The composition comprising the rice bran-derived low molecular weight peptide prepared in this way can be used as a raw material or food additive form of health food. The present invention will be described in more detail by the following examples. These examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited to these examples.

Example 1

1.5 g of rice bran sterilized and stabilized with water vapor was put in a 50 ml falcon tube, and water was added to dissolve the water-soluble protein. The pH of each solution was added by diluting the 10N caustic soda solution appropriately, and then adjusted to the pH and supplemented with water until the final 50ml. The final pH of each vessel is shown below. Extraction time of each container was the same 30 minutes and the experiment was carried out while stirring periodically. After 30 minutes elapsed, 1 ml of the lysate was taken from each container, and the protein concentration present in the supernatant obtained by centrifugation at 10,000 g for 5 minutes was determined by comparing the protein content by measuring absorbance at a wavelength of 280 nm. The value at the measured wavelength of each sample was measured relative to distilled water.

The results show that the alkaline conditions treated with rice bran show that the soluble protein is dissolved more as the pH of the solution rises. In particular, the concentration of dissolved protein is significantly increased above pH 10.

Example 2

Prepare the sample in the same manner as in Example 1, but adjust the pH of the extraction solution to 12 or more, alkali extraction for 30 minutes, remove the insoluble substance, and then dilute the citric acid appropriately and add differentially to the pH of each solution Lowered. The final pH of each container is shown in the figure below. The protein extraction concentration of the supernatant obtained by taking 1 ml of solution from each vessel at each final pH and centrifuging at 10,000 g for 5 minutes was determined by the following formula. The value at the measured wavelength of each sample was measured relative to distilled water.

The results show that the amount of protein present in the supernatant drops sharply below pH 6, indicating that most of the soluble proteins form precipitates in this pH range, especially in the range of 3.5 to 4.5. have.

Example 3

After taking 1.5g of stabilized rice bran as in Example 1 and put in different containers, the volume of water added was treated differently as shown below. The pH of the solution was adjusted to 12 or more, left for 10 minutes, the insoluble matter was removed, and the amount of carbohydrates present in the dissolved supernatant was determined according to the method of Dubois M. et al (Colorimetric method for determination of sugars and related). substances. Anal. Chem. 1956, 28 pp 350-356). At this time, glucose and fructose were prepared by 0, 10, 20, 30, 40, 50, and 60ug, respectively, and analyzed simultaneously with the sample. The quantitative value of the sample was calculated as the average of the values obtained by substituting each standard. After induction of color development through phenol-sulfuric acid treatment, quantification was performed at 490 nm.

The results show that as the volume of water treated increases, the total amount of water-soluble carbohydrates tends to be lowered, and the recovery of total sugars is obtained within the range of 919 mg to 1163 mg. Therefore, the range in which a large amount of sugar extract can be obtained while minimizing the volume to be treated is preferably in the range of 30 ml to 70 ml per gram of rice bran.

Example 4

After 3g of rice bran was suspended in 100ml of water, the pH of the solution was adjusted to 12 or more and left for 30 minutes. After removing the insoluble substance, glacial acetic acid was added to lower the pH of the solution to 4.24, and then 4 ml of each solution was dispensed into four containers. The supernatant was discarded by centrifugation at 10,000 g for 5 minutes, and the precipitate was taken and then vacuum-dried for 24 hours in a centrifugal vacuum dryer (speed vac). As a result of measuring the weight of the obtained dry precipitate, the precipitate was obtained with an average of 15% relative to the weight before drying. This is shown in the table below.

From the above table, the average weight of the settled dry matter contained in the initial 4ml was 24.25mg, which was converted to 100ml of total extraction volume, and about 606mg of precipitate was obtained. Therefore, since the weight of the rice bran used in the early 3g, the extraction efficiency of about 20% compared to the initial weight was obtained.

Example 5

In Example 4, the precipitate was recovered by centrifugation with a sample adjusted to pH 4.24 with an organic acid, and the change in the amount of protein distributed in each supernatant and precipitate after centrifugation compared to the total protein before separation of the protein by precipitation. Investigate. Protein quantification was determined using a protein concentration calculation formula of Example 2 after vortex and sufficient dissolution by adding the measurement sample to 20 ml of glacial acetic acid in a range of 20ul to 50ul. As a result, it was confirmed that the protein content in the precipitate obtained through the organic acid treatment was distributed in a ratio of 9: 1 (precipitate: supernatant).

These results were also confirmed by electrophoresis results through 15% SDS-PAGE.

Example 6

In order to calculate the content of protein contained in the precipitate dried product obtained in Example 4, 100 ml NaOH solution was added to each precipitate obtained in four vessels to a final 1 ml. In Example 4, the average dry precipitate weight of each container was found to be 24.25 mg. Immediately after sufficient dissolution to obtain the protein dissolved in 100 mM NaOH solution, each vessel was centrifuged at 10,000 g for 5 minutes, and each obtained supernatant was taken in 20 ml of 80% glacial acetic acid solution as in Example 5, and shaken sufficiently to clear it. The protein concentration was then determined in the same manner.

As a result, the amount of protein dissolved in 1 ml of 100 mM NaOH solution was obtained as 19.2mg, 21.1mg, 22.7mg, 25.4mg, and contained an average of 22,11mg of protein. As a result, about 91% of the weight obtained as dry weight was determined as protein.

Example 7

In order to lower the molecular weight of the protein obtained by precipitation using an organic acid from the alkaline extract of rice bran, the precipitate was suspended in 50mM Tris (pH 7.0) buffer and the protein concentration was measured in the same manner as in Example 5, and the protein concentration was 24.3. Samples of mg / ml were obtained. On the other hand, bromerlane (2.8 units / mg solid), a phytoprotein degrading enzyme, was purchased from Sigma, USA. Supernatant was used by dissolving 265 mg bromerlane powder in 10 ml of 50 mM Tris (pH 7.0) solution and centrifuging. The protein concentration of the supernatant was measured in the same manner as in Example 5 to obtain 17.3 mg / ml. The prepared bromelain enzyme solution was dispensed and stored in a freezer at -20 degrees until use. Enzyme reaction was performed by adding 100ul of 50mM Tris (pH 7.0) solution to 10ul of rice bran protein (equivalent to 2.43mg protein) and then adding 10ul of bromerlane enzyme solution (equivalent to 173ug protein) to the reaction in an oven adjusted to 55 degrees. Started. Samples were taken at 11, 23, 63, 90, and 135 minutes after the start of the reaction, and 100 ul of SDS-PAGE sample buffer (3X) was added and heated to stop the reaction. After all reactions were completed, 15% SDS- Electrophoresis was performed on PAGE to analyze the molecular weight of low molecular weight proteins.

From the results, it was confirmed that the two polymer proteins were all cut to a molecular weight of 6K or less under given conditions.

Example 8

In order to lower the molecular weight of the protein obtained by precipitation using organic acid as in Example 6, this time, the precipitate was planted in a rice bran protein suspended in 50 mM Tris (pH 7.0) buffer solution, papain (Papin, USA Sigma). Was treated. Supernatant was used by dissolving 270 mg papain in 10 ml of 50 mM Tris (pH 7.0) solution and centrifuging. The protein concentration of the supernatant was obtained as 23.9 mg / ml as measured before. The prepared papain enzyme solution was dispensed and stored at -20 degrees freezer until use. Enzymatic reaction was performed by adding 50ul of 50mM Tris (pH 7.0) solution to 100ul of rice bran protein (equivalent to 2.43mg protein) and then adding 10ul (equivalent to 239ug protein) of papain enzyme solution. It was.

Samples were taken at 17, 24, 35, and 60 minutes after the start of the reaction, and the reaction was stopped by adding SDS-PAGE sample buffer (3X) I00ul and heating, and electrophoresis was performed at 15% SDS-PAGE after all reactions were completed. The molecular weight size of the digested protein was compared and analyzed.

From the above results, it was confirmed that similarly to Example 7, two polymer proteins were cut to a molecular weight of 6K or less within 17 minutes under given conditions.

Example 9

The optimum reaction rate of bromerlane enzyme reacted with rice bran protein was investigated. After adding 86.5 ug, 17.3 ug, and 0.173 ug of different amounts of bromerlane enzyme to 2.43 mg of rice bran protein, respectively, and reacting at 55 ° C for 10 minutes, 15% SDS-PAGE was added as in the previous example. Through the results of the enzyme reaction was confirmed through the results are shown in the figure below.

As a result, despite the reaction for 10 minutes, the quantitative ratio of rice bran protein and enzyme was 14,000 (w / w), that is, low molecular peptide with molecular weight of 6,000 or less was formed in a container containing 0.173 ug of enzyme. It was confirmed that some of the protein is weakly present. Therefore, if the reaction time is more than 10 minutes, it was confirmed that all protein substrates can be low molecular weight even at 14,000: 1 (rice protein: bromelain, w / w) ratio.

Example 10

All the soluble proteins were extracted through alkali extraction performed in Example 4, and 30 ml of 99.5% ethanol was added to the remaining dehydrated insoluble rice bran. After ethanol extraction was performed for 2 hours at room temperature with sufficient shaking every 30 minutes, beta-sitosterol and stigmasterol according to the method of Careri et al ( Journal of Chromatography A. 935 (2001) 249-257). stigmasterol) analysis. In brief, ethanol extract is added to a mixture of ethyl acetate and water, and the mixture is sufficiently stirred. The aqueous layer is recovered, and the aqueous layer is extracted three times with ethyl ether, and the ethyl ether obtained is extracted with nitrogen gas. All of the residue was removed and redissolved by adding 1 ml of ethyl ether to the remaining residue. Standard beta-sitosterol was purchased from Sigma, USA, and dissolved in ethyl ether to a concentration of 100 ug / ml and used as a high pressure reverse phase C8 HPLC column (reverse phase C8, 0.46 cm x 25 cm, Vydac column) confirmed the presence of abundant phytosterols in the insoluble matter of rice bran through the development and confirmed that phytosterols can be easily extracted and prepared by the method of this embodiment in rice bran. The HPLC development results of the standard and ethanol extracted samples are shown in the figure below.

The figure above shows the development of standard (10ul, 100ug / ml) and the figure below shows the purity and content of phytosterol extracted in Example 10 of the present invention. Peak 1 in the standard (1ug) chromatogram is stigmasterol and peak 2 is beta-sitosterol. Column development conditions consisted of the mobile phase with acetonitrile-water (86.14, v / v) and the flow rate was 0.3 ml per minute. The measurement wavelength is 208 nm.

As described and demonstrated in detail above, the present invention provides a composition comprising a naturally-derived essential amino acid peptide, which is a bioactive substance, and a method for preparing the same. The present invention not only provides a method for enabling the mass production of essential amino acids, including low molecular weight bioactive substances beneficial to our bodies, from rice bran, which is produced in large quantities every year, at low prices, and primarily for the availability of rice bran. By extracting protein and obtaining high purity of phytosterol, which has a secondary cholesterol absorption inhibitory function from the remaining insoluble substance, it provides a method of simultaneously recovering two useful physiological substances from agricultural waste resources. This will not only make a great contribution to improving domestic farm income, but will also provide a foundation for extracting and supplying beneficial nutrients to our bodies from rice bran, which has been used as a livestock feed. The final product according to the present invention is a health-friendly substance such as organic acids and dietary fiber derived from various rice bran containing natural essential amino acids and vegetable sterols, and can be used as a low molecular total health food and food additives.

1 shows a method for preparing a composition comprising a low molecular peptide from rice bran

Claims (3)

Alkali extraction process from rice bran; Dehydration process to remove insoluble matters; Decomposing the protein using papain and bromelain; Method for producing a natural peptide derived from rice bran, including the step of recovering the low molecularized peptide using the ultrafiltration membrane In the process for producing a natural low molecular peptide of claim 1, the alkali extraction is a step of stirring at least 10 minutes to up to 2 hours at a pH of 10 or more while maintaining a water-soluble extraction volume of 30 to 100 liters per Kg rice bran; Adjusting the pH of the solution to a range of 5 to 8 by adding vinegar acid or citric acid to the alkaline extract solution from which the insoluble material is removed; The plant protease may use papain and bromelain, and in the process of treating it, it is possible to simply remove the naturally occurring low molecular peptide derived from the raw material, which includes maintaining the temperature of 60 ± 10 degrees. How to manufacture The method of claim 2, wherein the plant protease is characterized in that the use of bromerlane or papain, the optimum reaction ratio of bromerlane is in the range of 30 to 14,000 weight ratio of [rice bran protein] / [enzyme] How to handle while remaining