JP7001188B1 - Method for producing isolated plant-based protein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for producing a isolated plant-based protein. In particular, it is suitable for strengthening the protein of various foods, and even if it is added in a relatively large amount to various foods, it suppresses the influence on the shape, physical characteristics, texture, etc. of the food, so that it is possible to produce a separated plant protein having low water absorption. Provide the law. A method for producing an isolated plant-based protein, which comprises the following steps. (A) A step of concentrating a protein from a protein extract obtained by extracting a vegetable protein raw material with water to obtain a protein concentrate, (b) a pectinic polysaccharide or an alginate ester in the protein concentrate or its hydrolyzate. To obtain a mixed solution by adding 0.05% by weight or more to the protein, (c) heat-treat the mixed solution at 80 to 170 ° C. under acidic pH of 3.5 to 5.5, and heat-treated solution. (D) A step of pulverizing the heat treatment liquid to obtain a separated vegetable protein. [Selection diagram] None

Description

The present invention relates to a method for producing an isolated plant-based protein.

Proteins are macromolecules and often have gelling properties, thickening properties, and water retention (water absorption). Powdered vegetable protein products, such as soy protein isolate (SPI), which contains a high concentration of protein, are easier to distribute than liquid products because they do not contain water, and storage management is also possible. Cheap. Further, since the product can be blended in a high concentration in processed foods, it is widely used as a material for improving physical properties in various processed foods.
For example, soy protein has a well-balanced amino acid composition and has a physiological function typified by a serum cholesterol lowering action. Therefore, soy protein is used in nutritional and health-promoting foods that are expected to have nutritional and physiological functions.

According to the "2011 White Paper on Aging Society" released by the Cabinet Office of Japan, it is stated that the population of elderly people aged 65 and over will reach a record high of 29.58 million, and one in five will be elderly. A super-aging society (a society in which the percentage of elderly people aged 65 and over in the total population exceeds 21%) is imminent. Under these circumstances, the goal set forth in "Health Japan 21" promoted by the Ministry of Health, Labor and Welfare of Japan is to extend healthy life expectancy. "Healthy life expectancy" here refers to the period during which you can spend your life without any illness or disability, and healthy life expectancy (average independence period) = average life expectancy-non-independence period (independence that impairs your health) It is represented by the period during which you cannot live.

Ingestion of the required amount of nutritional components is essential for extending healthy life expectancy. In particular, proteins are essential substances for the maintenance of life, and they have various functions as well as constructing tissues. According to the "Japanese Nutrition Intake Standards" (2010 edition) presented by the Ministry of Health, Labor and Welfare, the recommended intake of protein is 60 g per day even for the elderly aged 70 and over, which is the same as for general adults. However, in general, elderly people are inactive in their daily activities. Therefore, the appetite of the elderly is reduced, and the food intake is reduced. Therefore, in the case of elderly people, it is necessary to efficiently ingest protein with a small amount of intake.

Under these circumstances, food manufacturers are focusing on developing processed foods for the purpose of supplementing plant protein by utilizing the excellent nutritional and physiological functions of plant protein. As one of the genres of processed foods, protein-enriched breads have been developed.
Here, isolated plant-based proteins such as isolated soybean protein have a high protein content, and are therefore suitable for the purpose of increasing the protein content of various foods. Further, since the material is in the form of powder, it has an advantage that it can be treated in the same manner as wheat flour. Further, since the material does not contain a large amount of water like soymilk, it has an advantage that the amount added to the food for strengthening the protein is not easily limited.

However, when a large amount of powdered plant protein is added to food for the purpose of strengthening the protein, the free water in the food is deprived by the water absorption generally possessed by the plant protein, and the functions of various raw materials in the food are exhibited. May interfere. Therefore, a food to which a large amount of powdered vegetable protein is added may impair the desired shape and physical properties, or may deteriorate the texture when eaten.

Therefore, it is required to provide a technique that does not impair the shape and physical properties of the food or deteriorate the texture when eaten even if a relatively large amount of powdered vegetable protein is added to the food. ..

Japanese Unexamined Patent Publication No. 11-243844 International release WO2007 / 114129 Japanese Unexamined Patent Publication No. 2009-142200 Japanese Unexamined Patent Publication No. 2016-2059 International release WO2016 / 147754 U.S. Pat. No. 4,504,679

Patent Document 1 describes a method for producing breads fortified with protein, which comprises adding powdered soybean protein and xylanase to bread dough. It has been described that this technique contributes to the prevention of a decrease in the specific volume of protein-enriched breads.

Patent Document 2 describes a powdered soybean protein material containing a magnesium salt such as magnesium oxide and partially hydrolyzed with a protease. In the examples, this powdered soybean protein material has an NSI of 32 and a 0.22M TCA solubility of 11%, an NSI of 17 and a TCA solubility of 10%, and an NSI of 45 and the TCA solubility. Those with a rate of 10% or those with an NSI of 30 and the TCA solubility of 22% are described. This technique has been described as being effective in the production of baked foods such as protein-enriched cookies.

An example of Patent Document 3 describes that a soybean puff (protein content 78% by weight) and a powdered soybean protein material are blended into a baked confectionery dough. The soybean puff is organized by an extruder, and this technology is characterized by using it.

In Patent Document 4, a paste containing 10 to 50% by weight of powdered soybean protein material is prepared, dried with hot air at 100 to 250 ° C. to a water content of 15% by weight or less, and powdered again. The soy protein material for fortification is described. It is described that the production of breads using the material contributes to the prevention of a decrease in the specific volume of protein-enriched breads.

As a method for producing a separated plant-based protein for increasing the protein content added to various foods, the methods such as Patent Documents 1 to 5 are provided.
However, in the method of Patent Document 1, the deterioration of bread quality due to the addition of soybean protein is compensated by the additive, and the essential modification of the isolated plant-based protein has not been achieved.
Patent Document 2 is a method of suppressing the water absorption of the material by adding a divalent metal salt and enzymatically decomposing the material, which improves the workability of food production, but increases the number of molecules per unit weight due to the reduction of the molecular weight of the protein. , Since the inhibition of the gluten network becomes stronger, it is not suitable for foods such as breads that require a high specific volume.
Patent Document 3 is characterized in that it is processed into granules by an extruder, and cannot be used as a powder similar to wheat flour.
In Patent Document 4, the water absorption is reduced by heat denaturation without reducing the molecular weight of the protein, but the present invention is characterized by more general equipment and treatment under practical conditions, and is efficient. Production is possible.

In view of the above, it is an object of the present invention to provide a new method for producing a isolated plant-based protein. In particular, it is suitable for strengthening the protein of various foods, and even if it is added in a relatively large amount to various foods, it suppresses the influence on the shape, physical characteristics, texture, etc. of the food, so that it is possible to produce a separated plant protein having low water absorption. Provide the law.
In another aspect, according to the present invention, when a protein solution is heat-treated in a heat treatment device in the process of producing a separated plant-based protein, the solution coagulates in the heat treatment device even if the solution is in the acidic pH range. Provides a processing method that does not.
In yet another aspect, the invention provides a isolated plant-based protein with a high bulk specific density.

As a result of diligent research on the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a new approach, and have completed the technical idea of the present invention.

That is, the present invention includes the following inventions.
(1) A method for producing a separated plant-based protein, which comprises the following steps, (a) a step of concentrating a protein from a protein extract obtained by water-extracting a plant-based protein raw material to obtain a protein concentrate. , (B) Add 0.05% by weight or more of pectinic polysaccharide or alginate ester to the protein concentrate or its hydrolyzate to obtain a mixed solution, (c) pH 3 of the mixed solution. A step of heat-treating at 80 to 170 ° C. under acidic conditions of .5-5.5 to obtain a heat-treated solution, (d) a step of pulverizing the heat-treated solution into a separated plant-based protein.
(2) The isolated plant-based protein according to (1) above, characterized in that the NSI of the isolated plant-based protein is 50 or less, the calcium content with respect to the protein is 0.6% by weight or less, and the magnesium content is 0.3% by weight or less. How to make protein,
(3) (e) A step of concentrating a protein from a protein extract obtained by extracting a plant-based protein raw material with water to obtain a protein concentrate, and (f) pH 3.5 to the protein concentrate or its hydrolyzate. In the process of producing a separated plant-based protein, which comprises a step of continuously heat-treating at 80 to 170 ° C. under the acidity of 5.5 to obtain a heat-treated solution, when the step (f) is performed, the protein concentrate is pectinic. A method for preventing protein coagulation in heat treatment under acidic conditions, which comprises mixing a polysaccharide or an alginate ester.
(4) (g) A step of concentrating a protein from a protein extract obtained by water-extracting a vegetable protein raw material to obtain a protein concentrate, (h) the protein concentrate or a hydrolyzate thereof at 80 to 170 ° C. In the step of performing heat treatment to obtain a heat treatment liquid and (i) the step of producing a separated vegetable protein having a step of pulverizing the heat treatment liquid, the protein is concentrated during the heat treatment of (h) step. Isolated vegetable origin, characterized in that the pH of the product or its water is kept acidic at 3.5-5.5, and the protein concentrate or its water is mixed with a pectinic polysaccharide or alginate ester. Protein Separation Method for increasing bulk specific gravity of vegetable protein,
(5) A method for producing a separated plant-based protein, which comprises the following steps, (a) a step of preparing a separated plant-based protein and adding water to the separated vegetable protein to obtain a protein concentrate, (b) the protein concentration. A step of adding 0.05% by weight or more of a pectinic polysaccharide or an alginate ester to a protein to obtain a mixed solution, (c) 80 to 170 of the mixed solution under acidic conditions of pH 3.5 to 5.5. A step of performing a heat treatment at ° C. to obtain a heat treatment liquid, and (d) a step of pulverizing the heat treatment liquid.

Although different from the object of the present invention, Patent Document 5 is characterized in that heat treatment is performed at pH 2 to 4, preferably pH 3.5 or less, which is a solubilization region on the acidic side of the isoelectric point of soybean protein. There is. In this respect, in the present invention, it is preferable to heat-treat in the pH region where the soybean protein is insolubilized.
Further, Patent Document 6 also discloses an invention of heat-treating a soybean protein at an isoelectric point, but the purpose thereof is to improve the flavor of the soybean protein material, which is different from the object of the present invention.

First, the present invention can provide a new method for producing a isolated plant-based protein.
As a side effect, according to the production method of the present invention, it is possible to provide a separated plant-based protein which is particularly suitable for fortifying proteins of various foods and has low water absorption. Thereby, according to an aspect of the present invention, even if it is added to various foods in a relatively large amount, it is possible to suppress the influence on the shape, physical characteristics, texture and the like of the food as a separated plant protein.
Further, according to the production method of the present invention, it is possible to provide a separated plant-based protein having a high bulk density. Due to these physical characteristics, the dispersibility in water, dough, etc. is enhanced, and the workability at the time of manufacturing various foods can be improved. In addition, the high bulk density makes it possible to make the packaging compact, which also contributes to space saving during storage.

Hereinafter, the present invention will be specifically described.

(Isolated plant protein)
In the present invention, the term "plant protein isolate" is used to remove components other than protein, that is, lipids, soluble sugars, starches, insoluble fibers (okara), etc. from the raw material of vegetable protein as much as possible. , Means a vegetable protein material enriched with protein. 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. In the present specification, the isolated plant-based protein provided by the present invention may be particularly referred to as "the present isolated plant-based protein".

(Vegetable protein raw material)
Examples of the vegetable protein raw material that is the raw material of the isolated vegetable protein include soybeans, peas, green beans, chick beans, peanuts, lupines, kimame, rape beans, vine beans, and green beans. , Beans such as red beans, sage, lens beans, sora beans, locust beans, seeds such as rapeseed seeds (especially canola varieties), sunflower seeds, cotton seeds, and grains such as wheat, barley, rye, rice, and corn. Examples thereof include whole grains and crushed products thereof, and beans obtained by industrially extracting fats and oils and starch from these can also be used. The major proteins contained therein have an isoelectric point of about pH 3-5, most typically about pH 4.4-4.6. In particular, it is preferable to use commercially produced soybeans, peas, mung beans, rapeseed seeds (canola seeds), and extracted meals of these fats and starches as separated proteins. For example, in the case of soybeans, full-fat soybeans, partially defatted soybeans, and defatted soybeans can be used.

Here, a method for producing the most typical isolated plant-based protein is illustrated.
First, a vegetable protein raw material is dispersed in an appropriate amount of water and water extraction is performed to remove an insoluble fraction mainly composed of fiber to obtain a protein extract. The protein extract is subjected to pH 3 to 5, preferably pH 4 to 5, more preferably pH 4.2 to 4.8, still more preferably pH 4.4 to 4.6, still more preferably pH 4.45 to 4 with an acid such as hydrochloric acid. The protein is adjusted to .55 and the protein is isoelectrically precipitated to remove the acid-soluble fraction (whey). The recovered acid-insoluble fraction (curd) is dispersed again in an appropriate amount of water to obtain a curd slurry. The curd slurry is neutralized with an alkaline agent such as sodium hydroxide to obtain a separated plant-based protein.
The isolated plant-based protein is heat-sterilized by a high-temperature heat treatment device in the state of a solution, generally spray-dried by a spray dryer or the like, and finally commercialized.
However, the above-mentioned production method using isoelectric point precipitation is not limited to a typical example, and a method for increasing the purity of a protein, such as a method for concentrating a protein by membrane filtration, is appropriately applied.

(Water-soluble polysaccharide)
One of the features of the method for producing the isolated plant-based protein is that a specific water-soluble polysaccharide is added in a specific step, and the obtained isolated plant-based protein contains the water-soluble polysaccharide. Here, the meaning of "containing a water-soluble polysaccharide" means that the isolated plant-based protein is integrated with other components such as a protein and is contained in a state in which it cannot be physically separated. Specifically, this state can be realized, for example, by homogenizing the protein and the water-soluble polysaccharide in the coexistence of the protein and the water-soluble polysaccharide by heat treatment or the like in an aqueous system. On the other hand, a protein obtained by simply mixing the separated plant-based protein and the water-soluble polysaccharide with each other does not fall under the present powdered separated protein. In addition, in this specification, a specific water-soluble polysaccharide contained in this isolated plant-based protein may be referred to as "this water-soluble polysaccharide".

■ Pectic polysaccharide This water-soluble polysaccharide is a pectic polysaccharide or an alginate ester. Of these, pectic polysaccharides are acidic polysaccharides containing galacturonic acid in the main chain. For example, water-soluble soybean polysaccharide, water-soluble pea polysaccharide, pectin and the like can be mentioned.

Water-soluble soybean polysaccharides and water-soluble pea polysaccharides are water-soluble polysaccharides composed of sugars such as rhamnose, fucose, arabinose, xylose, galactose, glucose and galacturonic acid, and are generally analyzed under the following conditions. The average molecular weight is 1 million or less by the gel filtration HPLC method. These can be prepared by extracting with water by a known method from a raw material containing insoluble dietary fiber (okara) of soybean or pea, and purifying if necessary. Commercially available water-soluble soybean polysaccharides can be used, for example, "Soya Five (R)" series (manufactured by Fuji Oil Co., Ltd.) and "SM" series (manufactured by Saneigen FFI Co., Ltd.). ) Etc. can be used. As the water-soluble pea polysaccharide, a commercially available product can be used, and for example, one obtained by the method described in International Publication WO2012 / 176852 and International Publication WO2014 / 103833 can be used.

For gel filtration HPLC, standard pullulan (Showa Denko KK) is used as a standard substance, and the analysis column "TSKgel G5000PWXL" (manufactured by Tosoh Corporation, column size: 7.8 mm I.D. × 30 cm, filler base material: methacrylate polymer) , Filler particle size: 10 μm, exclusion limit polymer weight: 2.5 million) is used. The average absolute molecular weight (MM) is determined by multi-angle laser light scattering (MALLS) calibrated with toluene after passing through the column. For example, use a 50 mM sodium acetate aqueous solution (pH 5.0) as the eluent, set the column flow velocity to 1.0 mL / min, and use the RI detector and the MALLS detector as the detectors. However, each analysis condition may be appropriately changed within a range in which a large error does not occur in the analysis value.

■ Alginic acid ester Alginic acid is a water-soluble polysaccharide derived from seaweed, and is an acidic polysaccharide containing mannuronic acid and glucuronic acid in the main chain. The alginic acid ester is a derivative in which propylene glycol is ester-bonded to the carboxyl group of uronic acid, which is a constituent sugar of alginic acid.

The content of the water-soluble polysaccharide in the solid content of the isolated plant protein is preferably 0.5% by weight or more. In a more preferred embodiment, the content can be 0.5% by weight or more, or 1% by weight or more. In some embodiments, the upper limit of the content may be 5% by weight or less, 4% by weight or less, or 3% by weight or less.

(Manufacturing example)
An example of production of this isolated plant protein is shown. Here, a production example is shown using defatted soybean as an example of a plant-based protein raw material, but by referring to this, other plant-based protein raw materials also require excessive trial and error according to the following production mode. It is possible to produce isolated plant-based protein without the need for production.

■ Manufacturing mode 1
An embodiment of producing the isolated soybean protein of the present invention from a plant protein raw material is shown.
I) Extraction step Add water to defatted soybeans and stir to make a suspension (slurry), and extract the protein with water. The pH of water can be neutral to alkaline, such as pH 6.5-9, preferably pH 7-9, more preferably pH 7-8. After extraction, the slurry is separated into an insoluble fraction (okara) mainly composed of insoluble dietary fiber by a solid-liquid separation means such as centrifugation to obtain a protein extract (so-called soymilk).

II) Protein concentration step Next, the protein is concentrated from the protein extract to obtain a protein concentrate. Typically, an acid such as hydrochloric acid or citric acid is added to the protein extract, the pH of the extract is adjusted to pH 4 to 5, which is the isoelectric point of soy protein, and the protein is insolubilized and acid-precipitated. .. Next, the supernatant (so-called whey) containing sugar and ash, which are acid-soluble components, is removed by a solid-liquid separation means such as centrifugation, and the “acid precipitation card” containing the acid-insoluble component is collected.
The acid precipitation card can be used as it is as a protein concentrate in the next step. Further, the acid precipitation card can be added with water as needed and neutralized with an alkaline agent to be used as a protein concentrate in the next step.
In some embodiments, instead of the acid precipitation method described above, a protein concentrate can be obtained by performing membrane concentration from the protein extract with an ultrafiltration membrane or the like.

III) Step of adding the water-soluble polysaccharide Next, water is added to the protein concentrate as necessary, and the curd is washed with water if necessary to obtain a liquid slurry. Then, the above-mentioned water-soluble polysaccharide is added to the slurry to obtain a protein-polysaccharide mixture.
The amount of the water-soluble polysaccharide added is at least 0.05% by weight or more per protein of the protein concentrate, and further 0.1% by weight or more, 0.3% by weight, 0.5% by weight or more or 0.7. It can be% by weight or more. The upper limit of the addition amount is not particularly limited, but 5% by weight or less per protein of the protein concentrate is appropriate, and further 4% by weight or less, 3% by weight or less, 2% by weight or less, 1.5% by weight or less or It can be 1.2% by weight or less.
By adjusting the amount of the water-soluble polysaccharide to the above-mentioned appropriate amount, a desired isolated plant-based protein can be produced.

It is important in the present invention that the protein-polysaccharide mixed solution is finally subjected to the next heat treatment step in a state where the pH is in the acidic pH range of 3.5 to 5.5. The pH range can be 3.8 or more, 4 or more, 4 or more, 4.05 or more, 4.1 or more, 4.2 or more, 4.3 or more, or 4.4 or more. Further, it can be 5.3 or less, 5 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, and the like. The adjustment to the acidic pH range is possible at any stage after the adjustment of the protein concentrate with an acid such as hydrochloric acid or citric acid and before the heat treatment in the next step. For example, the pH can be adjusted after obtaining the protein concentrate or after adding the water-soluble polysaccharide. Further, if the pH of the protein concentrate is already in the range of pH 3.5 to 5.5, it may not be necessary to adjust the pH.
By setting the pH to the above-mentioned appropriate value, a desired isolated plant-based protein can be produced.

IV) Heat treatment step Next, the mixed solution having a pH of 3.5 to 5.5 is heat-treated at 80 to 170 ° C. for 1 to 120 seconds. When a protein solution in the pH range near the isoelectric point is heat-treated, coarse aggregation may occur in the heat treatment device, and in the worst case, the piping of the heat treatment device may be blocked. In the present invention, by going through the step III) above, the occurrence of protein aggregation can be suppressed, and a stable and continuous heat treatment liquid can be obtained. As the heat treatment step, either an indirect heating method or a direct heating method can be used, and UHT sterilization is preferable. For example, a steam injection type continuous direct heat sterilizer such as a jet cooker device or a VTIS device (manufactured by Alfa Laval) can be used.
The heating temperature can be 90 ° C. or higher, 100 ° C. or higher, 110 ° C. or higher, 120 ° C. or higher, 130 ° C. or higher, or 140 ° C. or higher. Further, the temperature may be 160 ° C. or lower, 155 ° C. or lower, or 150 ° C. or lower. The heating time can be 2 seconds or more, 3 seconds or more or 4 seconds or more, and 100 seconds or less, 80 seconds or less, 60 seconds or less, 40 seconds or less, 30 seconds or less, 20 seconds or less or 10 seconds or less. Can be.
By setting the heating temperature to the above-mentioned appropriate temperature, a desired isolated plant-based protein can be produced.

V) Neutralization step If necessary, an alkali is added to the heat-treated solution to neutralize the solution to obtain a neutralized solution. The alkali used at this time is not limited in type as long as it is an alkali that can be used in food production such as sodium hydroxide, potassium hydroxide, and calcium hydroxide. A neutralization step is not always required before the powdering step, but if the purpose is to remove the acid added during the manufacturing step by neutralization, pH 6 to 8, pH 6.5 to 7.5, or pH 6.7 to It can be adjusted in the range of 7.3. The pH at this time is substantially equivalent to the pH of the isolated plant protein.

VI) Powdering step The neutralizing solution is dried and powdered to obtain the desired isolated plant-based protein. As the dryer, for example, a spray dryer, a drum dryer, a vacuum dryer, a freeze dryer and the like can be used, but a spray dryer is preferably used. As the 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. Further, if necessary, it can be granulated into granules by a fluidized bed granulator.

■ Manufacturing mode 2
As another embodiment, a commercially available isolated plant-based protein can be prepared and used as a starting material. In this case, the isolated plant-based protein is hydrated and used as the "protein concentrate" in the production embodiment 1, and the protein is subjected to the step of III) in the same manner as the subsequent steps to obtain the isolated plant-based protein. Can be done.

(Characteristics of this isolated plant protein)
The characteristics of this isolated plant-based protein obtained by the above are shown.
■ Solubility in water (NSI)
This isolated plant-based protein has low solubility in water. As the index, the NSI (Nitrogen Solubility Index) is 50 or less, and may be 45 or less, 40 or less, 37 or less, 35 or less, 30 or less, 25 or less, 22 or less, or 20 or less. Incidentally, in the case of "Fuji Pro F" (manufactured by Fuji Oil Co., Ltd.), which is a typical isolated soybean protein, the NSI is 99.5.

(NSI)
In the present invention, NSI can be expressed as the ratio (% by weight) of water-soluble nitrogen (crude protein) to the total amount of nitrogen based on a predetermined method, and in the present invention, it is measured according to the following method. Value.
That is, 60 ml of water is added to 3 g of the sample, the propeller is stirred at 37 ° C. for 1 hour, and then centrifuged at 1400 × g for 10 minutes to collect the supernatant liquid (I). Next, add 100 ml of water to the remaining precipitate again, stir the propeller again at 37 ° C. for 1 hour, centrifuge, and collect the supernatant liquid (II). Combine the solution (I) and the solution (II), and add water to the mixture to make 250 ml. This is filtered through a filter paper (NO.5), and then 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 a filtrate (water-soluble nitrogen) to the total amount of nitrogen in the sample is expressed as% by weight, which is defined as NSI.

■ Content of divalent metal salt On the other hand, there are isolated plant-based proteins whose NSI is lowered by processing such as addition of divalent metal salts such as calcium and magnesium, for example, those with NSI of 20 or more and less than 50. do. However, in the production method of the present invention, a isolated plant-based protein having a low NSI can be produced without adding a divalent metal salt. That is, the isolated plant-based protein can have a calcium content of 0.6% by weight or less and a magnesium content of 0.3% by weight or less with respect to the protein. The calcium content can be further 0.55% by weight or less, 0.5% by weight or less, 0.4% by weight or less, 0.3% by weight or less, or 0.2% by weight or less. The magnesium content can be further 0.2% by weight or less, 0.15% by weight or less, or 0.1% by weight or less. Furthermore, the isolated plant-based protein may be one to which a calcium salt and / or a magnesium salt has not been added during production. The contents of calcium and magnesium are measured by an official atomic absorption method.

■ Degradation degree (0.22M trichloroacetic acid solubility)
This isolated plant-based protein is also characterized by not being enzymatically decomposed by protease. A 0.22M trichloroacetic acid solubility (hereinafter referred to as "TCA solubility") can be used as an index of the absence of the enzymatic decomposition. The numerical value is the ratio of the protein dissolved in 0.22 M trichloroacetic acid to the total protein in the dispersion liquid in which the isolated plant-based protein is dispersed in water so as to have a protein content of 1.0% by weight and sufficiently stirred, using the Kjeldahl method. It was measured by. As the hydrolysis of the protein progresses, the value of TCA solubility increases.
The present vegetable protein material is characterized in that the TCA solubility is less than 10%. In certain embodiments, the TCA solubility may be up to 7% or less, 6% or less or 5% or less. Enzymatically degraded isolated plant-based proteins can often be a factor that negatively affects the shape and physical properties of various foods. This isolated plant-based protein is useful in such cases.

■ Water absorption This isolated plant-based protein is also characterized by its lower water absorption than typical isolated plant-based proteins. Since it is difficult to directly measure the water absorption rate, the water absorption level shall be evaluated using the following "water absorption evaluation method".
"Evaluation method of water absorption"
A mixture of 50 parts of isolated plant protein, 100 parts of water and 50 parts of soybean oil is stirred at 12000 rpm for 2 minutes using a homogenizer (manufactured by Nissei Tokyo Office, model number: ED-7) to obtain an emulsion dough.
When an emulsion dough can be prepared, the dough is filled in a container having a container diameter of φ = 5.5 cm and a container height of h = 1.5 cm so that air bubbles do not enter. Then, the hardness (gf) of the emulsion dough is measured using a texture analyzer (manufactured by Shimadzu Corporation, model number: EZ Test EZ-SX) under the conditions of a plunger diameter of φ = 18 mm and a measurement speed of 5 mm / sec. ..
The higher the water absorption, the higher the hardness of the emulsion dough, and if the water absorption is too high, the emulsion dough cannot be produced. Therefore, the level of water absorption is evaluated by the feasibility of producing an emulsion dough and the magnitude of the numerical value of the hardness (gf) of the dough.
The level of water absorption of the isolated plant-based protein is a level at which an emulsion dough can be produced by the above-mentioned measuring method, and the hardness of the dough is preferably 1300 gf or less, more preferably 1000 gf or less. By the way, in the case of "Fujipro F" (manufactured by Fuji Oil Co., Ltd.), which is a typical isolated soybean protein, the water absorption is too high to produce the emulsion dough.

■ Bulk density This isolated plant-based protein is also characterized by its high bulk density.
The bulk density of the isolated plant protein is 0.5 g / cm ³ or more, and can be 0.55 g / cm ³ or more, 0.6 g / cm ³ or more, or 0.65 g / cm ³ or more. Incidentally, in the case of "Fujipro F" (manufactured by Fuji Oil Co., Ltd.), which is a typical isolated soybean protein, the bulk density is about 0.45 g / cm ³ .
The bulk density is measured by using "POWDER TESTER model PT-X" (manufactured by Hosokawa Micron) and setting the tapping frequency to 180 times.

(Use of isolated plant protein)
As described above, this isolated plant-based protein has a property similar to that of "fine sand" because of its low water absorption and high bulk density. Therefore, even if it is added to various foods, it has a characteristic that it does not easily affect its shape, physical properties, texture and the like, and it can be used as a protein extender to enhance the protein of foods.
For example, by adding the isolated plant-based protein of the present invention to breads and the like, the protein can be strengthened while maintaining workability such as extensibility of the dough, swelling after baking, and quality such as texture. .. Similarly, in addition to bread, bakeries such as cookies, biscuits and pound cakes, noodles such as Chinese noodles, udon, soba and pasta, sweets such as chocolate, snacks, cereals and Japanese sweets, margarine, butter, fat spreads, etc. It can be used to fortify the protein of various foods such as processed fats and oils, tofu, fried tofu, processed soybean products such as cancer, powdered beverages, liquid beverages, and beverages such as soup.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples. In addition, "%" and "part" in an Example indicate "% by weight" and "part by weight" unless otherwise specified.

(Example 1)
10 parts of defatted soybean, which is a raw material for vegetable protein, and 100 parts of water are mixed and dispersed, and the protein is extracted at pH 7 for 30 minutes at 50 ° C while stirring with a homomixer, and then insoluble dietary fiber is used in a centrifuge. The insoluble fraction (okara) mainly composed of soybean was removed to obtain a protein extract.
Next, hydrochloric acid was added to the extract while stirring until the pH 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 slurry-like protein concentrate. The pH of the protein concentrate was 4.5.
To the protein concentrate, 1% of water-soluble soybean polysaccharide "Soya Five-S-DA100" (manufactured by Fuji Oil Co., Ltd.) was added to the protein, and the protein-polysaccharide mixed solution (pH 4.5) was added as it was. Got
Next, the mixed solution was heat-treated at 140 ° C. for 10 seconds with a steam injection type direct heat treatment device.
Sodium hydroxide was added to the obtained heat-treated solution to adjust the pH to 7 for neutralization, and the neutralized solution was spray-dried using a spray dryer to obtain separated soybean protein.

(Comparative Example 1) Change in pH during heat treatment (pH 7)
A separated soybean protein was obtained in the same manner as in Example 1 except that a water-soluble soybean polysaccharide was added to the protein concentrate (pH 4.5) of Example 1 and then adjusted to pH 7 with sodium hydroxide.

(Comparative Example 2) Change in pH during heat treatment (pH 2)
A separated soybean protein was obtained in the same manner as in Example 1 except that a water-soluble soybean polysaccharide was added to the protein concentrate (pH 4.5) of Example 1 and then adjusted to pH 2 with hydrochloric acid.

(Comparative Example 3) No addition of water-soluble soybean polysaccharide When the protein concentrate (pH 4.5) of Example 1 was directly subjected to the next heat treatment without adding the water-soluble soybean polysaccharide, the heat treatment apparatus. The operation was stopped because the agglomeration of the protein concentrate stuck in the pipe and blocked it, which made it impossible to continuously pass the liquid. Therefore, it was not possible to produce isolated soybean protein.

(Example 2) Change in pH during heat treatment (pH 4)
A separated soybean protein was obtained in the same manner as in Example 1 except that a water-soluble soybean polysaccharide was added to the protein concentrate (pH 4.5) of Example 1 and then adjusted to pH 4 with hydrochloric acid.

(Example 3) Change in pH during heat treatment (pH 5)
After adding a water-soluble soybean polysaccharide to the protein concentrate (pH 4.5) of Example 1, isolated soybean protein was obtained in the same manner as in Example 1 except that the pH was adjusted to 5 with sodium hydroxide hydroxide.

(Example 4) Change in the amount of water-soluble soybean polysaccharide added (0.1%)
Separated soybean protein was obtained in the same manner as in Example 1 except that 0.1% of water-soluble soybean polysaccharide was added to the protein of the protein concentrate (pH 4.5) of Example 1.

(Comparative Example 4) Change in the amount of water-soluble soybean polysaccharide added (0.01%)
Separated soybean protein was obtained in the same manner as in Example 1 except that 0.01% of water-soluble soybean polysaccharide was added to the protein of the protein concentrate (pH 4.5) of Example 1.

(Example 5) Change in the amount of water-soluble soybean polysaccharide added (3%)
Separated soybean protein was obtained in the same manner as in Example 1 except that 3% of water-soluble soybean polysaccharide was added to the protein of the protein concentrate (pH 4.5) of Example 1.

The production conditions of Examples 1 to 5 and Comparative Examples 1 to 3 are summarized in Table 1, and the analysis values of various components and the measured values of the physical properties of the isolated soybean protein obtained in each example are shown. The protein content indicates the content in the solid content, and the addition rate of calcium (Ca), magnesium (Mg), and water-soluble soybean polysaccharide indicates the addition rate per protein.

(Table 1)

(Discussion)
As shown in the result of Comparative Example 3, when the slurry-like protein concentrate is heat-treated at 100 ° C. or higher in the acidic pH region of pH 3.5 to 5.5 without adding the water-soluble soybean polysaccharide, the piping of the heat treatment device. It was shown that coarse agglomerates were clogged inside, making continuous heat treatment impossible.

On the other hand, in Example 1 in which 1.0% of the water-soluble soybean polysaccharide was added to the solid content of the protein concentrate, there was a surprising problem even if the heat treatment was performed at 100 ° C. or higher in the acidic pH region. Continuous treatment was possible without any problem, and isolated soybean protein could be produced.

In Comparative Example 1 and Comparative Example 2, the obtained isolated soybean protein was obtained probably because the pH of the protein concentrate during the heat treatment was in a region (pH2, pH7) away from the isoelectric point of the soybean protein, pH4.5. NSI was 70% or more, showing high solubility.

On the other hand, the NSI of the isolated soybean proteins obtained in Examples 1 to 3 in which the pH of the protein concentrate at the time of heat treatment was adjusted to the range of 3.5 to 5.5 was 30 or less, showing low solubility.

(Experimental Example 1) Examination of types of water-soluble polysaccharides Substitute water-soluble polysaccharides added to protein concentrates with water-soluble pea polysaccharides, alginate esters, sodium alginate, guar gum, tamarind gum, xanthan gum, chitosan, arabic gum, etc. An attempt was made to produce the isolated soybean protein in the same manner as in Example 1.
As a result, with respect to the water-soluble pea polysaccharide and the alginic acid ester, the same isolated soybean protein as in Example 1 could be produced. However, with other water-soluble polysaccharides, the piping of the heat treatment device was blocked and continuous liquid flow was not possible, so the operation was stopped. Therefore, isolated soybean protein could not be produced.

(Example 6)
Twelve copies of commercially available isolated soybean protein "Fujipro F" (manufactured by Fuji Oil Co., Ltd., protein content in solid content 91.0%) were prepared. This was added to 88 parts of water to make a protein concentrate (solid content 88%). The pH of the protein concentrate was 6.95.
To the protein concentrate, add 1% of the water-soluble soybean polysaccharide "Soya Five-S-DA100" (manufactured by Fuji Oil Co., Ltd.) to the protein, and then adjust the pH to 4.5 with hydrochloric acid. A protein-polysaccharide mixed solution was obtained. Subsequent steps were the same as in Example 1 to obtain processed soybean protein.
The obtained isolated soybean protein had the same physical characteristics as in Example 1.

(Example 7)
The isolated pea protein was produced in the same manner as in Example 1 except that the raw material for the vegetable protein was changed from defatted soybean to pea meal. The obtained isolated pea protein had the same physical characteristics as the isolated soybean protein of Example 1. From this, it was predicted that even if other vegetable protein raw materials were used, the same effect would be obtained if the same production process as in Example 1 was applied.

(Reference example) Comparison of components and physical properties of other products The components and physical properties of the isolated soybean protein obtained in Example 1 and samples A to E of various commercially available isolated soybean proteins (both manufactured by Fuji Oil Co., Ltd.). Was compared. The protein content indicates the content in the solid content, and the calcium (Ca) and magnesium (Mg) contents indicate the content with respect to the protein.

(Table 2)

As shown in Table 2, the isolated plant-based protein of Example 1 was able to reduce the water absorption to a measurable level.
The water absorption can be lowered by insolubilizing the protein by adding minerals as in Samples B and C, or by increasing the degree of protein decomposition as in Samples B to E. However, as can be understood by comparison with sample A, the water absorption of this isolated plant-based protein is low to the measurable region even though no minerals are added or the protein is decomposed. , Very characteristic.
Surprisingly, the isolated plant-based protein of Example 1 had the highest bulk density.

Claims (10)

In the step of producing a separated plant-based protein having an NSI of 50 or less, which comprises the following steps (a) and (b), the following step (c) is performed to prevent protein coagulation in heat treatment under acidic conditions. Method.
( A ) A step of concentrating a protein from a protein extract obtained by extracting a vegetable protein raw material with water to obtain a protein concentrate.
( B ) A step of continuously heat-treating the protein concentrate or its hydrolyzate at 80 to 170 ° C. under acidic pH of 4 to 5.5 to obtain a heat-treated liquid.
(C) A step of mixing a pectic polysaccharide or an alginic acid ester with the protein concentrate when performing the step ( b ). The method according to claim 1, wherein the pH of the step (b) is 4.3 to 4.9. The method according to claim 1 or 2, further comprising a step of neutralizing the heat treatment liquid in the step (b). The bulk of the isolated plant-based protein, which comprises the following steps (d) and (e) in the step of producing the isolated plant-based protein having an NSI of 50 or less, which has all the steps (a) to (c) below. How to increase the density.
( A ) A step of concentrating a protein from a protein extract obtained by extracting a vegetable protein raw material with water to obtain a protein concentrate.
( B ) A step of subjecting the protein concentrate or its hydrolyzate to a heat treatment at 80 to 170 ° C. to obtain a heat treatment liquid.
( C ) Step of pulverizing the heat treatment liquid ,
(D) At the time of the heat treatment in the step ( b ), the pH of the protein concentrate or its hydrolyzate should be kept under acidic conditions of 4 to 5.5 .
(E) At the time of the heat treatment in the step (b), a pectic polysaccharide or an alginic acid ester is mixed with the protein concentrate or its hydrolyzate. The method according to claim 4, wherein the pH of the step (d) is 4.3 to 4.9. The method according to claim 4 or 5, wherein the step (b) further comprises a step of neutralizing the heat treatment liquid before the step (c). The bulk density is 0.5 g / cm ³ The method according to any one of claims 4 to 6, which is the above. A method for treating an isolated plant-based protein, which comprises reducing the solubility in water to NSI 50 or less by going through all the steps (a) to (c) below .
(A) A step of preparing a separated plant-based protein and adding water to the isolated plant-based protein to obtain a protein concentrate.
(B) A step of adding 0.05% by weight or more of a pectic polysaccharide or an alginic acid ester to the protein concentrate to obtain a mixed solution.
(C) A step of heat-treating the mixed liquid at 80 to 170 ° C. under acidic pH of 4 to 5.5 to obtain a heat-treated liquid . The method according to claim 8, wherein the pH of the step (c) is 4.3 to 4.9. The method according to claim 8 or 9, further comprising a step of neutralizing the heat treatment liquid in the step (c).