WO2015098930A1

WO2015098930A1 - Plant protein isolate and production method therefor

Info

Publication number: WO2015098930A1
Application number: PCT/JP2014/084078
Authority: WO
Inventors: 伸介武田; 齋藤　努
Original assignee: 不二製油株式会社
Priority date: 2013-12-24
Filing date: 2014-12-24
Publication date: 2015-07-02
Also published as: JP5682697B1; CN105873453A; JP2015119655A

Abstract

　The purpose of the present invention is to provide a plant protein isolate that exhibits superior water dispersion properties, can be dissolved easily and rapidly, and is not susceptible to clumping, even when gently stirred as when a consumer dissolves a powdered beverage preparation in water at home.　This production method for a plant protein isolate having a NSI of 20 or higher but less than 90 is characterized by the following steps (a)-(c): (a) a step in which a protein-containing solution is prepared from a plant-based starting material, the protein-containing solution is subjected to the action of a phytase to partially hydrolyze the phytic acid therein, and an enzymatic reaction solution is obtained; (b) a step in which the enzymatic reaction solution from the preceding step is subjected to a high-temperature heat treatment a pH level of 5.5 or higher but less than 7.0, and a high-temperature-heat-treated solution is obtained; and (c) a step in which the high-temperature-heat-treated solution is converted into a dried powder.

Description

Plant-derived isolated protein and method for producing the same

The present invention relates to a vegetable isolated protein and a method for producing the same. In particular, the present invention relates to a method for producing a vegetable isolated protein excellent in dispersibility for powdered beverages.

Proteins such as soy protein are high molecular and amphiphilic, so there are gelling properties, thickening properties, water retention properties, and powdered protein materials such as concentrated proteins and separated proteins that contain this in high concentrations, Widely used as a physical property improving material for various processed foods.
For example, soy protein has a well-balanced amino acid composition and has physiological functions such as cholesterol-lowering action, and is used in nutritional and health-promoting foods that are expected to have nutritional and physiological functions.

Plant-derived isolated protein is a kind of powdery vegetable protein rich in protein. In the case of isolated soybean protein, soybeans whose protein concentration has been increased by removing insoluble fibers and carbohydrates in the aqueous system, usually using defatted soybean as a raw material. The protein solution is pulverized and manufactured by spray drying with a spray dryer or the like. A vegetable protein solution generally has a high protein water-holding power and a high viscosity of an aqueous solution, so that it is difficult to dry under conditions where the solid concentration is high. Therefore, the plant-isolated protein that is usually obtained is generally a fine powder and a light bulk specific gravity product. The plant-derived protein prepared in this way has a poor dispersibility in water, so that a so-called “mamako” duck floats on the surface of the aqueous solution, making it difficult to quickly dissolve in water. This is an essential improvement required when vegetable isolated protein is used as a raw material for powdered beverages and the like.

In order to solve such problems, as one method, a method for preventing the occurrence of mamako by increasing the dispersibility in water by granulating the vegetable isolated protein with a fluidized bed granulator is performed. ing. For example, a technique for spraying a granulated liquid containing emulsifiers and fats and oils on separated soybean protein and granulating it (Patent Document 1) is shown. Moreover, the technique which granulates isolation | separation soybean protein using the shaping liquid containing polysaccharides, such as dextrin, is also shown (patent document 2).

As another method for improving dispersibility in water, a method of spraying an acidic solution or an ionized aqueous metal solution onto separated soybean protein and drying is also known (Patent Documents 3 and 4).

Japanese Patent Laid-Open No. 6-113749 International Publication No. WO2003 / 22069 International Publication WO 2007/4624 International Publication No. WO2007 / 40048 Japanese Patent Publication No. 52-18720 JP-T-4-503002 International Publication WO2000 / 62623 JP 2002-51706 A Japanese Patent Publication No.55-29654 JP 51-125300 A International Publication WO2002 / 67690 International Publication WO2000 / 58492 International Publication No. WO2002 / 28198

In order to enhance the dispersibility of the plant-derived protein in water, the methods described in Patent Documents 1 to 4 are used. However, the granulation methods as described in References 1 and 2 require a large amount of excipients such as emulsifiers and polysaccharides, and the protein content in the plant-isolated protein product is reduced.
In addition, in the methods according to the cited references 3 and 4, the solubility of the plant-derived isolated protein obtained is lowered depending on the production conditions, and the mouth feels rough, or the flavor deteriorates over time during storage of the product. It takes a lot of skill to control the manufacturing process.

Therefore, an object of the present invention is to make powdered drinks less susceptible to mamako even under mild stirring conditions such as when consumers disperse them in water at home, excellent in water dispersibility, and easily and quickly dissolved. An object of the present invention is to provide an isolated vegetable protein.

As a result of intensive research on the above problems, the inventors of the present invention treated the plant protein-containing solution with phytic acid-degrading enzyme to partially hydrolyze phytic acid, and then obtained the enzyme reaction solution. A plant-isolated protein powder having a moderate solubility of NSI of 20 or more and less than 90 was obtained by high-temperature heat treatment under slightly acidic conditions of pH 5.5 or more and less than 7 to form a dry powder. When this powder was dissolved in water, it was found that the above-mentioned problem of being easily dispersed in water even under mild stirring conditions was found, and the technical idea of the present invention was completed.

That is, the present invention
(1) A method for producing a vegetable isolated protein having an NSI of 20 or more and less than 90, which comprises the following steps a) to c):
a) A protein-containing solution is prepared from a plant raw material, and phytic acid-degrading enzyme is allowed to act on this to partially hydrolyze phytic acid so that the phytic acid decomposition rate is 5% by weight to 48% by weight. Obtaining a liquid;
b) a step of subjecting the enzyme reaction solution having undergone the above step to a high temperature heat treatment at a pH of 5.5 to 6.9 to obtain a high temperature heat treatment solution;
c) a step of dry powdering the high temperature heat treatment liquid;
(2) The production method according to (1), wherein in step c), the high-temperature heat treatment liquid obtained in step b) is dry powdered at a pH of 5.5 to 6.9.
(3) The production method according to (1), wherein the protein-containing liquid is obtained by adding water to a vegetable raw material and then removing insoluble fibers and acid-soluble components.
(4) The production method according to (1), wherein the enzymatic reaction solution has a phytic acid decomposition rate of 10 to 40% by weight,
(5) The production method according to the above (1), wherein the pH in step b) is 6 to 6.8,
(6) In the process of producing a plant-derived isolated protein, a part of phytic acid is converted to a phytic acid part so that a phytic acid-degrading enzyme is allowed to act on the protein-containing solution so that the phytic acid decomposition rate is 5 wt% to 48 wt%. A method for improving the dispersibility of plant-derived separated protein in water, which comprises hydrolyzing the product into a decomposed product, and then heat-treating the enzyme reaction solution at a high temperature of 6 to less than 7.
(7) The method according to (6), wherein the enzymatic reaction solution has a phytic acid decomposition rate of 10 to 40% by weight,
(8) The NSI is 20 or more and less than 90, the phytic acid partial decomposition product and phytic acid coexist, and the pH of the 10% by weight aqueous dispersion is 5.5 or more and 6.9 or less. Powdered vegetable protein isolate,
(9) The powdered vegetable isolated protein according to (8), wherein the pH of the 10% by weight aqueous dispersion is 5.5 or more and 6.8 or less,
(10) The powdered vegetable isolated protein according to (8), wherein NSI is 20 or more and less than 55,
(11) The powdered vegetable isolated protein according to (8), wherein the NSI is 60 to 75,
(12) The phytic acid is decomposed so that the phytic acid degradation rate is 5% by weight or more and 48% by weight or less when the phytic acid partial degradation product and phytic acid are allowed to act on a protein-containing solution prepared from plant raw materials. A powdered vegetable isolated protein according to (8), which coexists by partially hydrolyzing
(13) Obtained by the production method described in (1) above, having an NSI of 20 or more and less than 90 and containing a partially decomposed phytic acid and phytic acid, the pH of the 10% by weight aqueous dispersion is 5. Powdered vegetable isolated protein, characterized in that it is 5 or more and 6.9 or less,
(14) Use of the powdered vegetable isolated protein according to (8) in a powdered beverage,
(15) A method for producing a powdered drink, comprising the powdered vegetable isolated protein according to (8) above,
It is.

In addition, referring to the technology that uses phytic acid-degrading enzyme in the production of soy milk and isolated soy protein, for example, phytic acid chelates minerals necessary for life support such as calcium, magnesium, iron, etc. In order to form, it is said to interfere with normal intestinal absorption of the mineral in the body. For this reason, phytic acid is removed from soybean protein as much as possible using phytic acid degrading enzyme for the purpose of reducing the influence on the mineral absorbability in the body (Patent Documents 5 to 8).
Further, in order to obtain an acid-soluble protein having improved solubility in an acidic region having a pH of 5 or less, phytase is used (Patent Documents 9 to 11).
Furthermore, phytase is allowed to act on soybean protein for the purpose of fractionating protein components into β-conglycinin (7S globulin) and glycinin (11S globulin) (Patent Documents 12 and 13).
However, both are used for the purpose of improving the dispersibility in water when the vegetable isolated protein is dissolved in water under relatively gentle stirring conditions, such as when consumers drink powdered beverages at home. It is not intended to be different from the technical idea of the present invention.

The plant-derived isolated protein obtained by the present invention has physical properties excellent in water dispersibility even under mild stirring conditions, so that it is difficult to produce mamako, and consumers can use it as a raw material for powder beverages at home. It can be easily and quickly dissolved. In addition, when drinking after dissolution, it is difficult to feel roughness in the mouth. Moreover, as a secondary matter, it is possible to provide a plant-derived isolated protein having a rich feeling when taken.

Hereinafter, the present invention will be specifically described.

(Vegetable isolated protein)
In the present invention, the “vegetable isolated protein” is a plant-derived protein in which components other than protein, that is, lipid, soluble sugar, starch, insoluble fiber (ocara), etc. are removed as much as possible from the plant raw material which is the raw material. A protein material. The protein content is generally 70% by weight or more, preferably 80% by weight or more, more preferably 85% by weight or more, and most preferably 90% by weight or more in the solid content.

Here, the plant raw materials include plant raw materials containing proteins, such as soybeans, peas, mung beans, chickpeas, peanuts, lupines, beans, nata beans, crane beans, kidney beans, red beans, cowpeas, lentils, Whole grains such as beans such as sola beans and locust beans, seeds such as rapeseed seeds (especially canola varieties), sunflower seeds and cottonseed seeds, and grains such as wheat, barley, rye, rice and corn The thing which the oil and fat and starch were industrially extracted from these can also be used. These plant raw materials usually contain phytic acid, and the main proteins contained in them have an isoelectric point around pH 4.5. In particular, it is preferable to use soybeans, peas, mung beans, rapeseed seeds (canola seeds) that are commercially produced as isolated proteins, and oils or starches extracted therefrom.

Here, a typical production example of isolated soy protein will be described below using soybean as an example. Even if other plant raw materials are used, the plant isolated protein can be produced by the following steps.
I) Extraction process The defatted soybean is used as a soybean raw material, added to this and stirred to obtain a suspension (slurry), and the protein is extracted with water. Water can have a neutral to alkaline pH. Okara is separated from this by solid-liquid separation means such as centrifugation to obtain a protein extract (so-called soy milk).
II) Acid precipitation step Next, acid such as hydrochloric acid or citric acid is added to the protein extract, and the pH of the extract is adjusted to pH 4-5, which is the isoelectric point of soybean protein, so that the protein is insolubilized and acid precipitated. Let Next, the supernatant (so-called whey) containing sugar and ash which are acid-soluble components is removed by solid-liquid separation means such as centrifugation, and an “acid precipitation card” containing acid-insoluble components is recovered.
III) Neutralization Step Next, water is added again to the acid precipitation curd and, if necessary, the curd is washed with water to obtain a “card slurry”. The slurry is neutralized by adding an alkali such as sodium hydroxide or potassium hydroxide to obtain a “neutralized slurry”.
IV) Sterilization / Powdering Step Next, the neutralized slurry is heat sterilized and spray-dried with a spray dryer or the like to obtain a separated soybean protein.
However, the isolated soybean protein in the present invention is not limited to those produced in the above production examples. As the soybean material, various soybean materials such as full fat soybean and partially defatted soybean can be used instead of defatted soybean. Various extraction conditions and devices can be applied to the extraction means. As a method for removing whey from the protein extract, membrane concentration using an ultrafiltration membrane or the like can be performed instead of acid precipitation. In this case, a neutralization step is not necessarily required. Furthermore, after removing whey from a soybean raw material by washing with acidic water or alcohol in advance, it can be produced by applying a method of extracting protein with neutral or alkaline water.

(Step a) -Enzyme reaction-
Step a is a step in which a protein-containing solution is prepared from a plant raw material, and a phytic acid-degrading enzyme is allowed to act on this to obtain an enzyme reaction solution.
The protein-containing solution to be enzymatically reacted is an arbitrary step of the process for producing a vegetable isolated protein, for example, any of steps I) to IV) in the case of producing a vegetable isolated protein in the production process described above. Any liquid may be used as long as it contains the protein prepared in (1). Even when a vegetable isolated protein is produced in a process other than the production example, it may be a liquid containing a protein obtained in any process. More specifically, (a) a slurry (suspension) obtained by adding water to a vegetable raw material and mixing or crushing if necessary, (b) a protein extract obtained by further separating insoluble fibers from the slurry (In the case of soybeans, it is also referred to as soy milk), (c) an acid precipitation card obtained by separating whey from the protein extract by acid precipitation or the like, a card slurry obtained by further adding water, and (d) the card. A neutralized slurry obtained by neutralizing a slurry by adding an alkali, and (e) a heated neutralized slurry obtained by heat-treating the neutralized slurry.
More preferably, a protein-containing solution in which the insoluble fiber and the acid-soluble component are removed and the protein is further concentrated after adding water to the plant raw material, such as (c) to (v), is suitable.

Next, a phytic acid-degrading enzyme is allowed to act on the obtained protein-containing solution to hydrolyze a part of phytic acid into a partially decomposed phytic acid to obtain an enzyme reaction solution.
Examples of the enzyme that degrades phytic acid include phytase and phosphatase, and an enzyme preparation having both of these activities can also be used. For example, “Sumiteam PHY” manufactured by Shin Nippon Chemical Industry Co., Ltd. can be used as a commercially available enzyme agent.
In order to hydrolyze a part of phytic acid into a phytic acid partial degradation product, the conditions for the action of the enzyme can be selected by appropriately selecting various conditions, and are not particularly limited. However, if phytic acid is hydrolyzed too much, most of the phytic acid is decomposed. Therefore, the phytic acid content (P) before the enzymatic reaction and the phytic acid content (Q) after the enzymatic reaction are measured, It is desirable to obtain the “rate” and determine the operating conditions using this as an index of the degree of hydrolysis.
(Formula) Decomposition rate of phytic acid = (PQ) ÷ P × 100
In this case, the phytic acid decomposition rate is preferably 5 to 50% by weight, more preferably 5 to 48% by weight, and even more preferably 10 to 40% by weight. In other words, it is possible to obtain a vegetable protein material with increased mineral absorption in the body as in the past, obtain a high-purity soybean 7S globulin material or soybean 11S globulin material, or improve acidity in an acidic pH region. For the purpose of obtaining dissolved protein, the phytic acid degradation rate is desirably as close to 100% by weight as possible, but in the present invention, it is more desirable to suppress the phytic acid degradation rate to the above specific phytic acid degradation rate.
If the phytic acid decomposition rate is too high, that is, if phytic acid is excessively removed during the manufacturing process, the dispersibility will be good, but it will be easier to feel a deteriorating odor that has deteriorated the quality, which will affect the flavor. May affect. On the other hand, when the phytic acid decomposition rate is too low, that is, when the degree of removal of phytic acid is too small during the production process, it tends to be difficult to obtain the effect of improving the dispersibility in water.

The pH of the protein-containing solution when the enzyme is allowed to act is not particularly limited as long as the phytic acid-degrading enzyme used can maintain the activity. For example, the reaction can be performed in the range of pH 2 to 10, preferably 3 to 8.
The working temperature of the enzyme may be a temperature range in which the phytate decomposing enzyme to be used is active, and can be, for example, 20 to 70 ° C., preferably 25 to 65 ° C.
The amount of the enzyme to be added varies depending on the activity of the phytate decomposing enzyme to be used, and can be, for example, 0.1 to 100 unit / g, preferably 0.5 to 50 unit / g based on the solid content. 1 unit of phytase activity represents the amount of enzyme that liberates 1 μmol of phosphoric acid from the substrate phytic acid during the first minute of the reaction under standard conditions (pH 5.5, 37 ° C.).
The action time of the enzyme can usually be in the range of 5 minutes to 6 hours.

Since free phosphoric acid is generated by hydrolysis of phytic acid in the resulting enzyme reaction solution, it can be further removed by a purification means such as electrodialysis, but in the present invention, free phosphoric acid is removed. It is not essential and free phosphoric acid can be contained as it is.

(Process b)-High temperature heat treatment-
Step b is a step in which the enzyme reaction solution obtained through step a is subjected to high temperature heat treatment at a pH of 5.5 or more and less than 7 to obtain a high temperature heat treatment solution.
In the case of the above production example, the protein-containing liquid in step a is obtained in any one of steps I) to IV). Therefore, the enzyme reaction solution undergoes the necessary steps before heat treatment, and at least the steps Prepare a neutralized slurry of III).
The pH of the neutralized slurry is 5.5 to less than 7, more preferably 6 to 6.9, still more preferably 6.1 to 6.8, and even more preferably 6.3 to 6.7 before the high temperature heat treatment. It is important to adjust to. When adjusting the neutralization slurry from the card slurry, the pH adjustment may be once adjusted to pH 7 or higher with an alkali and then finely adjusted to the range again with acid, or directly to the range with an alkali. .
If the pH of the solution during the high-temperature heat treatment becomes too low, aggregation occurs during the high-temperature heat treatment, or the solubility of the resulting vegetable isolated protein becomes too low and may be dispersed in water. It will be a grainy quality. On the other hand, when the pH is too high, the NSI of the obtained plant-derived isolated protein becomes too high, and the dispersibility in water decreases.
For the high-temperature heat treatment process, either an indirect heating method or a direct heating method can be used, and UHT sterilization is preferable. For example, it is possible to use a steam injection type continuous direct heat sterilizer such as a jet cooker device or a VTIS device (manufactured by Alfa Laval), and heat treatment can be performed at 105 to 180 ° C. for 0.5 to 180 seconds. .

(Process c)-Dry powderization-
Step c is a step of converting the high-temperature heat treatment liquid obtained through step b into dry powder.
Dry powdering can be carried out with the high-temperature heat treatment solution treated at a pH of 5.5 or more and less than 7, preferably in the range of pH 5.5 to 6.9, while maintaining the pH value. It is also possible to carry out after adjusting the pH of the treatment liquid to a desired pH (for example, pH 4 to 7.5) in advance. The pH of the final product can be selected in consideration of the flavor and mouthfeel when the vegetable isolated protein powder is dissolved in water, but in any case, the high-temperature heat-treated solution is pH 5.5 or more and less than 7 It is preferable to form a dry powder in the pH range of 5.5 to 6.9.
As the dryer, for example, a spray dryer, a drum dryer, a vacuum dryer, a freeze dryer and the like can be used, and a spray dryer is preferably used. As drying conditions of the spray dryer, for example, the blowing temperature can be about 100 to 200 ° C., and the exhaust air temperature can be about 60 to 100 ° C.

(Partial hydrolysis with protease)
Although the vegetable isolated protein of the present invention is not essential, it may be partially hydrolyzed by a protease for the purpose of further reducing NSI or improving the flavor.
The degree of hydrolysis of the plant-derived separated protein can be expressed using 0.22M trichloroacetic acid solubility (TCA solubility) as an index. The degree of degradation can be appropriately adjusted within the range of 0 to 30%, for example, by changing the amount of protease added and the action time according to the desired quality.

In the present invention, the dry powder obtained in step c can be used as it is as a vegetable isolated protein product. In addition, for the purpose of further improving dispersibility in water, etc., the vegetable powder is separated through further processing such as further pulverizing, granulating, or combining the dry powder as described below. It can also be a protein product.

(Pulverization)
As the pulverizer, any of a direct pressure pulverizer, a disk pulverizer, a roller pulverizer, a cylinder pulverizer, an impact pulverizer, a jet pulverizer, and the like can be used. By pulverization treatment, the average particle size of the obtained vegetable isolated protein powder can be adjusted to 20 to 60 μm, preferably 20 to 40 μm.

(Granulation)
As the granulator, a wet granulator or a dry granulator can be used, but a fluidized bed granulator is preferably used. At that time, a liquid in which, for example, 0.1 to 2% by weight of an emulsifier such as lecithin, fats and oils, saccharides and the like are appropriately mixed can be used.

The plant-derived protein obtained as described above has the following characteristics and is an unprecedented novel composition.

(NSI)
The plant isolated protein of the present invention has an NSI (Nitrogen Solubility Index) of 20 or more and less than 90, that is, a plant isolated protein or NSI having an NSI of 90 or more and a very high solubility. It is an important feature that the solubility is reduced to NSI in the intermediate region of the plant isolated protein with very low solubility below.
On the other hand, in the case of vegetable isolated proteins with NSI of 90 or more, the solubility in water is too high, so it is very damaging when dissolving under conditions of low speed agitation where consumers agitate manually at home. This tends to be difficult and the dispersibility tends to be poor. Further, in the case of a plant-derived protein having an NSI of less than 20, there is no problem in dispersibility in water, but it is not preferable because it tends to feel the roughness in the mouth very strongly.
NSI of the plant-derived isolated protein of the present invention can be selected from 20 to less than 55, and more preferably from 30 to 50, as an aspect having relatively low solubility in the range of 20 to less than 90.
Further, as another embodiment having relatively high solubility, those having 55 or more and less than 90 can be selected, and those having 60 to 75 can be selected. The level of NSI can be selected by those skilled in the art as appropriate from the viewpoint of flavor and water solubility.

In addition, NSI can be represented by the ratio (wt%) of water-soluble nitrogen (crude protein) in the total nitrogen amount based on a predetermined method. In the present invention, NSI is a value measured according to the following method. .
That is, 60 ml of water is added to 3 g of the sample, and the mixture is stirred with a propeller at 37 ° C. for 1 hour, and then centrifuged at 1400 × g for 10 minutes, and the supernatant (I) is collected. Next, 100 ml of water is again added to the remaining precipitate, and the mixture is again stirred with a propeller at 37 ° C. for 1 hour, and then centrifuged to collect the supernatant (II). The liquid (I) and liquid (II) are combined, and water is added to the mixture to make 250 ml. After filtering this with a filter paper (NO. 5), the nitrogen content in the filtrate is measured by the Kjeldahl method. At the same time, the amount of nitrogen in the sample is measured by the Kjeldahl method, and the ratio of the amount of nitrogen recovered as filtrate (water-soluble nitrogen) to the total amount of nitrogen in the sample is expressed as% by weight.

(Phytic acid)
Since the plant-isolated protein of the present invention is obtained by hydrolyzing a part of phytic acid, a part of the undegraded phytic acid remains. Phytic acid refers to the hexaphosphate ester of myo-inositol. In the case of ordinary vegetable isolated protein that does not have a phytic acid removal step in the manufacturing process, it cannot be said unconditionally because it varies depending on the origin and lot of the plant raw material. Usually about 2 to 3% by weight is contained.
In contrast, the plant isolated protein of the present invention has a phytic acid content lower than that of a normal plant isolated protein when plant raw materials of the same lot are used.
The phytic acid content in the present invention is determined by directly measuring the phytic acid content in the solution according to the Alii Mohamed method (Cereal Chemistry 63, 475, 1986).

(Partially decomposed phytic acid)
The phytic acid partial degradation product is a general term for inositol monophosphate (IP1), inositol diphosphate (IP2), inositol triphosphate (IP3), inositol tetraphosphate (IP4) and inositol pentaphosphate (IP5). Among the six phosphate esters in the phytic acid molecule, some are hydrolyzed to become hydroxyl groups.
In the case of vegetable isolated proteins that do not have a phytic acid hydrolysis step in the production process, almost no phytic acid partial degradation products are detected.
On the other hand, the vegetable isolated protein of the present invention contains a phytic acid partial degradation product together with undegraded phytic acid as a result of partial hydrolysis of phytic acid. Therefore, whether or not a phytate degrading enzyme is allowed to act as in the present invention in a plant isolated protein product can be determined by confirming by HPLC or the like whether or not the partial degradation product is detected. . This determination need not be quantitative, and qualitative determination based on the presence or absence of detection is sufficient.

(PH of aqueous dispersion)
The vegetable isolated protein of the present invention preferably has a pH of 5.5 or more and less than 7 when prepared in a 10% by weight aqueous dispersion.
If the pH is too low, the dispersibility in water is not bad, but it tends to feel the roughness in the mouth. On the other hand, if the pH is too high, the roughness in the mouth is not felt, but the dispersibility in water becomes worse. It becomes a trend.
The pH is preferably 6 or more, more preferably 6.1 or more, further preferably 6.2 or more, and further preferably 6.3 or more. Moreover, 6.9 or less is preferable, 6.8 or less is more preferable, and 6.7 or less is further more preferable.

(Protein composition)
The protein composition of the plant-derived isolated protein of the present invention is not particularly limited. In the case of isolated soybean protein, the ratio of 11S globulin (glycinin) and 7S globulin (β-conglycinin), which are the main components, is defatted. What is close to the ratio of soybean raw materials such as soybeans is desirable. When general soybeans that are not special soybeans deficient in 11S globulin or 7S globulin by genetic manipulation or breeding are used as raw materials, the ratio of 11S globulin to the total amount of 11S globulin and 7S globulin is 100 to 400% by weight. Is preferred. That is, in this case, it is preferable not to have a step of fractionating 11S globulin or 7S globulin to a level exceeding the range. This is because, in the case of having a step of fractionating 7S globulin and 11S globulin after water extraction of the protein from the soybean raw material, the fractionation purity of 7S globulin and 11S globulin is lowered unless phytic acid is highly decomposed.

(Use of plant isolated protein)
The vegetable isolated protein obtained by the present invention is widely used in applications requiring such quality because it is excellent in water dispersibility. It is particularly suitable for applications that require good dispersibility under mild stirring conditions, and particularly suitable for powdered beverages. Powdered beverages are also called dry blended beverages overseas.
By using the vegetable isolated protein of the present invention in a powdered beverage, a high-protein and high-nutrient powdered beverage can be obtained while maintaining good dispersibility in water.
The vegetable isolated protein of the present invention can be blended in a wide range of blending ratios in a powdered beverage, for example, 1 to 99% by weight can be blended. Although not particularly limited, 5 to 50% by weight, further 10 to 40% by weight can be blended when considering the balance with other nutrients.
In addition to vegetable isolated protein, sugar powder, dietary fiber, fats and oils, emulsifiers, fragrances, sweeteners, and the like can be appropriately mixed with the raw material of the powdered beverage in accordance with the quality desired by the manufacturer.

Hereinafter, embodiments of the present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” indicate “% by weight” and “parts by weight” unless otherwise specified.

(Test Example 1) High-temperature heat treatment of phytase reaction solution at various pHs 10 parts of defatted soybean meal were dispersed in 100 parts of water, and the protein was stirred at 50 ° C. for 30 minutes while stirring with a homomixer (manufactured by Special Machine Industries Co., Ltd.). After extraction, insoluble dietary fiber (Okara) was removed using a centrifuge to obtain a protein extract.
Next, hydrochloric acid was added with stirring until the pH of the extract reached 4.5, the supernatant was removed by a centrifuge, and the acid precipitation card was collected.
This acid precipitation curd (4 parts of solid content) was dispersed in 40 parts of water to obtain a curd slurry, and sodium hydroxide was added to the slurry to neutralize the pH to 7.2 to obtain a neutralized slurry of soybean protein. .
Next, while maintaining the temperature of the neutralized slurry at 50 ° C., 0.5% of phytase “Sumiteam PHY” (manufactured by Shin Nippon Chemical Co., Ltd., enzyme activity 2,000 unit / g) is added to the neutralized slurry and stirred. Then, phytase was allowed to act for 1 hour to obtain an enzyme reaction solution. At this time, the phytic acid decomposition rate after the enzyme reaction of the neutralized slurry was 15%.
Next, the enzyme reaction solution is divided into nine types, and the pH is adjusted to 5.0, 5.6, 5.8, 6.0, 6.3, 6.7, 6.9, 7.0, 7.2, respectively, and is heated at 120 ° C. with a steam injection type direct heating apparatus. Heat treatment was performed for 2 seconds to obtain each high-temperature heat treatment liquid (tests 1 to 9).
Next, each high-temperature heat treatment liquid was spray-dried with a spray dryer at the same pH to obtain a powder of separated soy protein.
NSI of each of the obtained separated soy protein powders was measured, and the dispersibility in water was evaluated, and sensory evaluation was performed on the roughness and texture in the mouth. The evaluation method was as follows.

○ Dispersibility in water 20g of separated soy protein is put in a 200mL capacity cup containing 100g of water at 60 ° C, stirred by hand with a stir bar for 1 minute, and then filtered with a tea strainer (20 mesh, JIS standard). After the moisture was cut off, the moisture at the bottom of the tea strainer was wiped off with waste paper, the amount of remaining mamako (g, water content) was measured, and the dispersibility in water was evaluated. Whether the dispersibility was improved or not was compared using the amount of Mamako of Test 8 as a control.

○ Sensory evaluation 10 taste panelists asked to taste a powdered beverage in which soy protein isolate was dissolved in a 10% solution. The average score was calculated and considered. The scoring criteria are 10 points for the paneler who thinks that the degree of roughness is the smallest, and 1 point for what the paneler thinks that the degree of roughness is the largest, with 1 to 10 points depending on the difference. . An average score of 5 points or more was regarded as a passing score.
Separately, the presence or absence of richness was evaluated as an optional evaluation item. 10 points were given by the panelists as having the strongest feeling, and 1 point was given by the panelists as having the least richness.

(Table 1)

When the enzyme reaction solution was adjusted to pH 5 and heat-treated as in Test 1, agglomeration occurred in the heat-treatment process, and the NSI was significantly lower than 20 or less. Although the dispersibility in water was good with a small amount of Mamako, the solution after dispersion in water immediately precipitated, and the mouth was strongly felt to be rough. From Test 2 onwards, it was much better than Test 1 in terms of roughness. Also, until Test 7, Mamako amount was suppressed to just over 10g. Furthermore, after Test 4, the richness tended to increase, and the texture was more preferable.

As in Tests 8 and 9, when the enzyme reaction solution was adjusted to pH 7 or higher and heat-treated, NSI was 90 or higher, and the water solubility became considerably high. The solution after dispersion in water was good with no roughness in the mouth, but conversely, 20g or more of mamako was generated and the dispersibility was very poor.

Separately, instead of setting the pH of the curd slurry to 7.2 in Test Example 1, the phytase is applied after pre-adjusting to the same value (6.3, 6.7, 6.9, respectively) during the high-temperature heat treatment in Tests 5-7. When subjected to high-temperature heat treatment as it was and spray-dried to obtain separated soybean protein, all of these had the same quality as Tests 5-7.

(Test Example 2) Effect of Phytic Acid Degradation Rate A neutralized slurry of soy protein (pH 7.2) was obtained from defatted soybean flakes in the same manner as in Test Example 1.
Next, the neutralized slurry was divided into five types, and while maintaining the temperature at 50 ° C., phytase “Sumiteam PHY” (manufactured by Shin Nippon Chemical Co., Ltd.) was added to these at 0% (no addition), 0.1% , 0.5%, 1%, and 5% were added, and phytase was allowed to act for 1 hour with stirring to obtain each enzyme reaction solution (tests 10 to 14). At this time, the phytic acid content before and after each neutralization slurry was measured, and the phytic acid decomposition rate after the enzyme reaction was calculated. As a result, the phytic acid decomposition rate of each enzyme reaction solution of Tests 10 to 14 was 0% and 13%, respectively. %, 26%, 48%, and 95%.
Next, the pH of each enzyme reaction solution was adjusted to 6.8, and heat treatment was performed at 120 ° C. for 60 seconds using a steam injection type direct heating device to obtain each high temperature heat treatment solution.
Next, each high-temperature heat treatment liquid was spray-dried as it was using a spray dryer to obtain a separated soy protein powder.
NSI of each of the obtained separated soy protein powders was measured, and evaluation of dispersibility in water and sensory evaluation of roughness and texture in the mouth were performed in the same manner as in Test Example 1.

(Table 2)

As in Test 10, when the enzyme reaction with phytase was not performed, the separated soy protein obtained had a mamako amount of 20 g or more, and the dispersibility was very poor.

As shown in Test 14, when phytase was added in an excessive amount and reacted, the resulting isolated soy protein was almost hydrolyzed with phytic acid, and the amount of mamaco was small and the dispersibility was good. The graininess was felt very strongly, the flavor also felt a deteriorating odor, and the quality tended to deteriorate.

(Test Example 3)
The high-temperature heat-treated liquid obtained in the same manner as in Test 6 of Test Example 1 was divided into two parts, adjusted to pH 5.8 and pH 7, respectively, and spray-dried to obtain isolated soy protein (Tests 15 and 16). ).
These were all as good in quality as the isolated soy protein of Test 6, but Test 15 tended to be more rough and less dense than Test 6. On the other hand, since the dispersibility of Test 16 tended to be lower than that of Test 6, the quality of the isolated soy protein of Test 6 was relatively superior.

From the above test results, an isolated soy protein having an NSI of 20 or more and less than 90, containing a partially decomposed phytic acid and phytic acid, and having a 10% strength by weight aqueous dispersion having a pH of 5.5 or more and less than 7, It was found that it is very suitable as a protein material used under mild stirring conditions such as powdered beverages because of its excellent water dispersibility and little roughness. This knowledge can be applied to plant raw materials containing phytic acid and protein as well as soybean.

Claims

A method for producing a vegetable isolated protein having an NSI of 20 or more and less than 90, which comprises the following steps a) to c):
a) A protein-containing solution is prepared from a plant raw material, and phytic acid-degrading enzyme is allowed to act on this to partially hydrolyze phytic acid so that the phytic acid decomposition rate is 5% by weight to 48% by weight. A step of obtaining a liquid.
b) A step of obtaining a high-temperature heat-treated solution by subjecting the enzyme reaction solution having undergone the above-described step to a high-temperature heat treatment at a pH of 5.5 to 6.9.
c) The process of making the said high temperature heat processing liquid into dry powder.
The process according to claim 1, wherein, in step c), the high-temperature heat treatment liquid obtained in step b) is dry powdered at a pH of 5.5 to 6.9.
The production method according to claim 1, wherein the protein-containing liquid is obtained by adding water to a vegetable raw material and then removing insoluble fibers and acid-soluble components.
The process according to claim 1, wherein the enzymatic reaction solution has a phytic acid decomposition rate of 10 to 40% by weight.
The process according to claim 1, wherein the pH in step b) is 6 to 6.8.
In the process of producing a plant-derived isolated protein, a part of phytic acid is converted into a partially decomposed phytic acid so that a phytic acid degrading enzyme is allowed to act on the protein-containing solution so that the phytic acid decomposition rate is 5% by weight to 48% by weight. A method for improving the dispersibility of plant-derived separated proteins in water, which comprises hydrolyzing and then heat-treating the enzyme reaction solution at a high temperature of 6 to less than 7.
The method according to claim 6, wherein the enzymatic reaction solution has a phytic acid decomposition rate of 10 to 40% by weight.
Powder having a NSI of 20 or more and less than 90, a phytic acid partial decomposition product and phytic acid coexisting, and a 10% by weight aqueous dispersion having a pH of 5.5 or more and 6.9 or less Plant-like isolated protein.
The powdery vegetable isolated protein according to claim 8, wherein the pH of the 10% by weight aqueous dispersion is 5.5 or more and 6.8 or less.
The powdery vegetable isolated protein according to claim 8, wherein NSI is 20 or more and less than 55.
The powdered vegetable isolated protein according to claim 8, wherein the NSI is 60 to 75.
Phytic acid partial hydrolyzate and phytic acid are used to partially hydrolyze phytic acid so that the phytic acid degrading enzyme is allowed to act on a protein-containing solution prepared from a plant raw material so that the phytic acid decomposition rate is 5% by weight to 48% by weight. The powdery vegetable isolated protein according to claim 8, which coexists by being decomposed.
The NSI is 20 or more and less than 90, obtained by the production method according to claim 1, wherein a phytic acid partial decomposition product and phytic acid are contained, and the pH of a 10% by weight aqueous dispersion is 5.5 or more and 6. A powdery vegetable isolated protein, characterized in that it is 9 or less.
Use of the powdered vegetable isolated protein according to claim 8 for powdered beverages.
A method for producing a powdered beverage comprising blending the powdered vegetable isolated protein according to claim 8.