JP2013226135A - Protein material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protein material of high versatility usable for various food and drinks even with high concentration because of being easily dispersible in water, low in viscosity even with high protein concentration to hardly cause a physical change peculiar to protein such as gelling and coagulation by heating, and causing neither precipitation nor separation by insolubilization even at a pH in the vicinity of an isoelectric point of protein so as to have stability on the practically usable level.SOLUTION: A novel protein material is obtained by hydrolyzing a dispersion of protein to a specific range, and in a state of containing insoluble high molecular protein fractions produced by the hydrolysis, conjugating specific water-soluble polysaccharide with protein.

Description

  The present invention relates to a protein material that can be widely used for various foods and drinks.

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.

  According to the 2011 White Paper on Aging Society published by the Cabinet Office, the population of elderly people over 65 years old is the highest ever, 29.58 million people, 1 in 5 people become elderly people. The society that accounts for more than 21% of the total population). Under such circumstances, the extension of healthy life expectancy is cited as a goal of “Healthy Japan 21” promoted by the Ministry of Health, Labor and Welfare. The healthy life span here is the period of time during which you could spend without any illness or disability. Healthy life span (average independence period) = average life span-non-independence period (period in which you can't live independently and lose health. ).

  The intake of the necessary amount of nutrients is essential for extending the healthy life expectancy. Among them, protein is an indispensable substance for the maintenance of life, and plays various functions as well as constructing tissues. According to the “Japanese Nutrition Intake Standards” (2010 edition), published by the Ministry of Health, Labor and Welfare, the recommended amount of protein is 60 g per day for elderly people over 70 years of age, the same as for general adults. However, in general, daily living activities become inactive in elderly people, and the amount of food intake decreases with a decrease in appetite. Therefore, it is necessary to efficiently ingest protein with a small amount of intake.

  Under such circumstances, foods aimed at supplementing proteins for the elderly are being developed by utilizing the excellent nutritional physiological functions of various proteins. However, protein is a polymer with physical properties such as gelling properties and thickening properties. Therefore, when blended into products such as powdered beverages and RTD beverages (Ready-to-drink), physical properties are limited by thickening. At present, there are many restrictions on the amount added and the pH of use due to the weight of food, the texture, and the precipitation at the isoelectric point of the protein.

Milk whey protein is a protein that dissolves in acid and is relatively often used in powdered beverages and RTD beverages. However, pectin is often used in acidic gel foods such as jelly, and even milk whey protein has high reactivity with pectin due to the influence of electric charge in a solution having an acidic pH below its isoelectric point, There is a problem that the protein and pectin react to cause aggregation. For this reason, the function of pectin as a gelling agent was impaired along with protein aggregation and precipitation, and a gel-like food with a uniform and smooth tissue could not be obtained.
Therefore, it is still difficult to design foods so that such proteins can be efficiently replenished in a small amount.

  In general, hydrolysis with a protease is used as a method for decreasing the viscosity of a protein or weakening gelation. In order to maintain a sufficiently low viscosity even when the protein is highly blended in powdered beverages and RTD beverages, when the protein is highly hydrolyzed, it is not subject to much hydrolysis and is an insoluble and relatively high molecular weight protein fraction (HMF). Therefore, peptide materials obtained by separating and removing these and recovering soluble low molecular weight peptides have been produced.

  This peptide material has very high solubility in water, and a uniform protein solution with low viscosity can be obtained without precipitation even under acidic conditions. However, on the other hand, it has a strong unpleasant taste such as a bitter taste or an egg taste derived from the enzyme degradation product, and has a low palatability, resulting in an industrially low recovery rate and a high cost product. And in order to reduce this bitterness, application of various quality improvement means was needed, and the complicated process was added, and it had to be a more expensive product (patent document 1).

Japanese Patent Laid-Open No. 7-264993 JP-A-62-242 JP 2003-250459 A JP-T-2006-521788 Special table 2007-508817 Special Table 2007-536924

Conventional undegraded protein materials and high-degradation peptide materials have difficulty satisfying both the properties that are less affected by the physical properties of the protein and the properties that have less unpleasant taste such as bitterness and taste.
Accordingly, the object of the present invention is to provide a low-viscosity, low-viscosity property of protein-specific physical properties such as gelation or coagulation due to heating even at a high protein concentration, and unpleasant tastes such as bitterness and egg taste derived from enzymatic degradation products of proteins. In addition, it has a practically usable level of stability, and is not easily precipitated or separated due to insolubilization even at a pH near the isoelectric point of protein, and has a practically usable level of stability. The object is to provide a highly versatile protein material that can be used even at high concentrations.
A further object of the present invention is to provide means for stably reinforcing the protein of an acidic gel food using pectin without affecting the gelation of pectin using this protein material.

  As a result of intensive studies on the above problems, the present inventors have hydrolyzed a protein dispersion to a specific range and contained a polymer insoluble protein fraction produced by the decomposition treatment. , Discovered that a novel protein material obtained by complexing a specific water-soluble polysaccharide with a protein can solve the above problems, and using the novel protein material of the present invention and pectin using the same The technical philosophy of applied foods such as acid gel foods was completed.

That is, the present invention provides the following.
(1) A protein material that satisfies the following requirements 1 to 4.
1. The protein content per dry matter is 50% by weight or more,
2.0.22M TCA solubility is 30-70%,
3. Water solubility at pH 3.5, pH 4.5 and pH 5.5 are all 30-70%,
4). A water-soluble polysaccharide is contained so that the zeta potential of the aqueous dispersion of the protein material is -10 to 20 mV at pH 2-3.
(2) The protein material according to (1), wherein the water solubility at pH 7 is 30 to 70%.
(3) The protein material according to (1) above, wherein the viscosity at pH 7 of a 19 wt% aqueous dispersion in terms of protein is 1000 mPa · s or less at 20 ° C.
(4) The protein material according to (3), wherein the viscosity of the 19% by weight aqueous dispersion in terms of protein after heating at 95 ° C. for 10 minutes at pH 7 is 1000 mPa · s or less at 20 ° C.
(5) The protein material according to the above (1), wherein the 1% by weight aqueous dispersion in terms of protein has a storage sedimentation rate of 5% or less at pH 4, pH 5 and pH 5.5.
(6) A protein hydrolyzate having a 0.22M TCA solubility of 30 to 70% and a water-soluble soy polysaccharide, the protein hydrolyzate and the water-soluble soy polysaccharide are combined, and per dry matter The protein material characterized by having a protein content of 50% by weight or more.
(7) The protein material according to (6) above, wherein the protein hydrolyzate is derived from soybeans.
(8) A method for producing a protein material comprising the following steps.
1. The aqueous dispersion containing protein is hydrolyzed with a proteolytic enzyme so that the 0.22M TCA solubility is 30 to 70%, and a protein hydrolyzate containing insoluble protein produced by the decomposition treatment is obtained. Obtaining step,
2. A step of mixing a protein or protein hydrolyzate and one or more water-soluble polysaccharides in an aqueous system, wherein the water-soluble polysaccharides have a zeta potential of an aqueous dispersion of the protein material at a pH of 2 to 3. All are water-soluble polysaccharides that are -10 to 20 mV,
3. A step of conjugating a protein hydrolyzate and the water-soluble polysaccharide.
(9) An acidic gelled food gelled with pectin and reinforced with protein, wherein the protein material according to any one of (1) to (7) is used as the protein. Characteristic acid gel food,
(10) The acidic gelled food according to (9), wherein the acidic gelled food is gelated by a reaction between LM pectin and a divalent metal ion,
(11) A method for producing an acidic gelled food according to (10) above, wherein a solution containing LM pectin and the protein material and a divalent metal ion are mixed and gelled.
(12) A liquid base for acidic gel food containing LM pectin and a protein material for preparing an acidic gel food by mixing with divalent metal ions and gelling, 1) A liquid base for acidic gel food, wherein the protein material according to any one of (7) is used;
(13) A hermetic mixture containing LM pectin and the protein material according to any one of (1) to (7) for mixing with divalent metal ions and gelling to prepare an acidic gel food. A set for preparing an acidic gel food, characterized in that the liquid base for container packed acidic gel food is combined with a divalent metal ion or its content in a sealed container,
(14) Cold water-soluble LM pectin for preparing an acidic gel food by mixing with divalent metal ions and gelling, the protein material according to any one of (1) to (7) and An acidic gel food powder base, characterized by containing a valent metal ion,
(15) The acidic gel food according to (9), wherein the pectin is HM pectin, the protein is 10 to 40% by weight, the saccharide is 30 to 80% by weight, and the pH is 3 to 4. An acidic gel food characterized by being 4.

  In addition, although the technique of disperse-stabilizing protein with water-soluble polysaccharide is seen also in patent documents 2-6 etc., all differ in the technical idea from this invention.

  For example, Patent Documents 2 to 6 disclose techniques for increasing the dispersion stability of proteins at acidic pH by adding high methoxyl pectin or carboxymethyl cellulose to the protein, but a solution having a protein concentration exceeding 10%. Is not considered for thickening before and after heating at each pH, and dispersion stability in a wide pH range regardless of acidity or neutrality, and to provide a practically stable soy protein material Absent.

According to the present invention, it is possible to provide a protein material that has a low viscosity even when added to a high concentration and hardly changes in physical properties such as gelation or aggregation due to heating.
In addition, it is possible to provide a protein material that has less unpleasant taste such as egg taste and acidity as well as bitterness derived from an enzyme degradation product that is not preferable in preference. Therefore, various flavorings can be performed on the final product, and natural flavoring can be performed.
In addition, according to the present invention, it is possible to easily disperse a protein in water in any pH food or drink from acidity to neutrality, and there is little roughness and excellent dispersion stability. A highly protein material can be provided.
Therefore, according to the protein material of the present invention, it is not necessary to sequentially examine other proteins suitable for each pH and concentration of food and drink, and can be widely used.
And, if the protein material of the present invention is used, even if it is added to an acidic gel food using pectin, the pectin and protein will not electrically react under acidic pH to cause aggregation, and the protein can be stably added. A fortified acidic gel food can be produced.

  Hereinafter, the present invention will be specifically described.

(Protein material)
In the present invention, the protein material is a raw material material mainly composed of protein and used in the manufacture of various foods and beverages and other processed products. This protein material is prepared by further processing from a raw material containing protein (protein raw material).

  Examples of protein raw materials include soy protein extract (also referred to as soy milk) from which water-soluble components including protein and sugar are extracted with water or hot water to remove insoluble fibers (ocara), or soy protein extraction. The solution can be further processed and manufactured based on a powdered soy protein obtained by further purifying the liquid to increase the purity of the protein, or an intermediate product obtained during the production of the powdered soy protein. As an intermediate product, soybean protein card obtained by adjusting soybean protein extract to pH 4-5 with acid such as hydrochloric acid or citric acid, isoelectric precipitation of soybean protein, and removal of soluble fraction (whey) Alternatively, a soy protein solution in which a soy protein curd is neutralized with an alkali and redispersed can be used. Extracts, concentrated proteins, isolated proteins, etc. derived from plant materials other than soybeans (beans such as peas, cereals such as wheat, rice and corn, rapeseed, sunflower seeds, etc.) and animal materials (milk, etc.) Various protein raw materials can be used in the same manner as soybeans.

  In the present invention, it is possible to provide a protein material having a high protein content of at least 50% by weight, preferably 60% by weight or more, more preferably 70% by weight or more, and 70% by weight or more. In this case, it is preferable to produce the protein using separated protein, concentrated protein or intermediate product thereof.

  For example, in the case of soybeans, as raw materials for obtaining a protein extract, whole fat soybeans, partially defatted soybeans obtained as a residue that has been physically squeezed by press extraction, etc., and soybean oil extracted with a solvent such as n-hexane In addition, defatted soybeans obtained in this manner, and soybeans that can be extracted with soy protein, including okara (insoluble fiber content) such as concentrated soy protein, can be used. When producing a lower-fat soy protein material, defatted soybeans may be used as a raw material, or partially defatted soybeans or full-fat soybeans as raw materials, and only protein is extracted, or protein and oil are extracted together. The oil may be separated from the oil by centrifugation or the like to reduce the fat.

For the separated soy protein, the pH of the soy protein extract is adjusted to a pH (4-5) near the isoelectric point of the soy protein to remove the whey component and the protein component which is an insoluble component is separated and recovered, or limited. What was obtained by removing soybean whey components by membrane filtration using an outer filtration membrane or the like and increasing the protein concentration can be used.
In addition, as the soy protein extract or separated soy protein, the one containing a lot of β-conglycinin or glycinin obtained by fractionation of protein components or using soybeans rich in specific protein components is also used. it can.

  In addition to soybeans, vegetable raw materials containing vegetable proteins as well as soybean proteins can be used in the same manner as described above or protein raw materials with increased protein concentrations by other purification methods. In the case of milk, a concentrated or separated milk protein such as casein or whey can be used as a protein raw material.

(TCA solubility)
In the protein material of the present invention, it is important that the protein is decomposed to a specific decomposition range. The hydrolysis treatment can be performed on an aqueous dispersion containing protein. The specific hydrolysis of the protein includes stabilization of the water dissolution rate at the acidic pH of the protein material of the present invention, lowering of the viscosity of the aqueous dispersion, suppression of increase in viscosity due to heating of the aqueous dispersion, and reduction of the storage sedimentation rate ( It contributes to the reduction of unpleasant astringency that is particularly felt with acidic aqueous dispersions.

  As a measure of the degree of protein degradation, it can be expressed as 0.22M trichloroacetic acid solubility (TCA solubility). This value is dispersed in water so that the protein content is 1.0% by weight as protein content. The ratio of 0.22M trichloroacetic acid (TCA) soluble protein based on the total protein was measured by the Kjeldahl method for the well-stirred solution. As protein degradation proceeds, the TCA solubility increases.

  One feature of the protein material of the present invention is that it has a specific intermediate degree of degradation of 0.22M TCA solubility of 30 to 70%, and the solubility is at least 30%, preferably 35. It is appropriate that it is decomposed to more than%. The solubility is suitably 70% or less, preferably 60% or less, more preferably 55% or less. When the 0.22 M TCA solubility is too low, thickening at the time of high blending into food becomes a problem, and blending into food is difficult in terms of physical properties. On the other hand, if it is too high, the bitterness becomes too strong, and it becomes difficult to add it to food in terms of palatability.

  The degree of degradation of the protein material of the present invention uses this TCA solubility as an index. When viewed in terms of the molecular weight of the protein, the average molecular weight is preferably about 10,000 to 50,000, more preferably about 17,000 to 40,000, and about 19,000 to 30,000. Is more preferable. The average molecular weight can be measured by the method described later.

  The hydrolysis of the protein is preferably enzymatic degradation with a protease. As the protease, for example, a protein in which amino acids are bound in a chain or an endo-type protease that is an enzyme that hydrolyzes peptide bonds inside a peptide to form several peptides are suitable. It is also possible to combine one or more exo-type proteases, which are enzymes that sequentially cleave amino acids and peptides from the amino terminus and carboxy terminus present at the ends of proteins and peptides. These endo-type proteases and exo-type proteases can be used as long as they have activity in a protein material solution in a pH environment. Those derived from microorganisms such as Aspergillus genus, Rhizopus genus and Bacillus genus, and those derived from plants can be preferably used. Among these, those derived from microorganisms are preferable.

As proteases derived from the genus Aspergillus, "Sumiteam ^(R) ACP" (manufactured by Shin Nippon Chemical Industry Co., Ltd.), "Protease M (Amano) G" (manufactured by Amano Enzyme Co., Ltd.) (from Aspergillus oryzae), "Orientase ^(R) 20A" (manufactured by HIBI), "Denapsin ^(TM) 2P" (manufactured by Nagase ChemteX Corporation) (from Aspergillus niger), "Nurase ^(R) from Rhizopus genus""F3G" (Amano Enzyme Co., Ltd.), Bacillus-derived "Protin ^(TM) SD-NY10" (Amano Enzyme Co., Ltd.), "Orientase ^(R) 10NL" (manufactured by HBI Corporation), etc. Can be mentioned.

The reaction temperature is generally 20 ° C. or higher and 70 ° C. or lower, although it depends on the type of enzyme used. If it is less than 20 ° C., it may be industrially unfavorable because the protease activity is low and it is necessary to increase the amount of enzyme added. If it exceeds 70 ° C., it may be inactivated by heat denaturation depending on the type of protease.
The solution pH of the protein material during the reaction depends on the type of enzyme used and the optimum pH, but can be appropriately selected from about pH 2 to 12, preferably 3 to 11.

  When the above hydrolysis treatment is carried out, a relatively high molecular weight insoluble protein fraction that generally has not undergone much hydrolysis is produced. This fraction is a so-called “HMF” (High Molecular Fraction) fraction. In the production of the protein material of the present invention, the HMF is left unseparated or partially separated, and the protein containing HMF It is important to use a hydrolyzate. Thus, leaving HMF affects the range of water solubility at each pH below.

(Water solubility at each pH)
The protein material of the present invention is characterized in that the water solubility is 30% or more and 70% or less at any of pH 3.5, pH 4.5 and pH 5.5. The fact that the water solubility at these three pH points is within such a range means that the water solubility is substantially within a wide acidic pH range including the isoelectric point of many proteins of pH 3.5 to 5.5. Means that it is maintained. For reasons of viscosity at the time of high blending, the water solubility is preferably 40% or more in the above pH range, and more preferably less than 60% for reasons of flavor.

  Here, since the water solubility of proteins generally increases as they move away from the isoelectric point of the protein, naturally the water solubility in the range of less than pH 3.5 and more than pH 5.5 is within the above range or more, In the present invention, the water solubility at pH 7 can also be within the above range. Moreover, the water solubility here is the water solubility of the protein material which is the final product, and it is not necessary that the intermediate satisfies the water solubility in the above range.

  If the water solubility is too low, the viscosity at the time of high blending tends to be high, and conversely if too high, the bitterness tends to be strong on the flavor side. A water solubility of 30% or less at all three pH points indicates that the protein material tends to be a poorly soluble polymer. On the other hand, a water solubility of 70% or higher at all pHs tends to be a higher degradation product or a separated peptide obtained by separating and removing HMF and recovering only soluble peptides. Undegraded products and low-degraded products have pH 4.5 and pH 5.5 of 30% or less.

The isoelectric point of protein is in the vicinity of pH 4.5 in many cases like soy protein and milk protein. For example, commercially available isolated soy protein has a water dissolution rate of about 30-40% at pH 3.5, 5-15% at pH 4.5, 10-20% at pH 5.5, 80-90% at pH 7, etc. The closer to the electrical point, the greater the drop. However, the protein material of the present invention maintains a constant water solubility even near the isoelectric point of the protein.
In other words, the water solubility of a certain range is maintained without paying attention to the fluctuation of the water solubility due to the isoelectric point of the protein in a wide pH range, and this property is for practical use in a wide pH range. is important.

  In the present invention, the water dissolution rate at each pH is measured as follows. The water solubility (%) used in the present invention is a measure of the solubility of a protein in a solvent, and is defined as follows. In other words, the ratio of the total amount of the supernatant protein obtained by dispersing the protein material in water so that the amount of protein is 1% by weight and thoroughly stirring the solution after adjusting to each pH and then centrifuging for 10,000 G x 5 minutes to the total protein is Kjeldahl. It was measured by the method.

(Water-soluble polysaccharide)
In the production of the protein material of the present invention, a protein or protein hydrolyzate is mixed with a specific water-soluble polysaccharide in an aqueous system. And it is important to finally pass through the process of making it act with a protein hydrolyzate, and compounding these. As a result, the protein material of the present invention is complexed with a specific water-soluble polysaccharide, thereby suppressing unpleasant unpleasant taste and improving the storage stability of the aqueous dispersion in a wide pH range, and high concentration. An increase in viscosity before and after heating of the aqueous dispersion is suppressed, and an aqueous dispersion having a low concentration imparts the effect of suppressing protein aggregation due to heating.

Examples of water-soluble polysaccharides that can impart such effects include water-soluble polysaccharides in which the zeta potential of an aqueous dispersion of a protein material obtained by complexing with a protein hydrolyzate is -10 to 20 mV at pH 2-3. It is important to use sugars. In this case, it is preferably −10 to 10 mV at pH 3, and more preferably −10 to 5 mV. Further, at pH 6, it is preferably -20 to 0 mV, and more preferably -18 to 0 mV.
In the present invention, the zeta potential can be measured by a designated method using “Zetasizer ^(R )” (manufactured by Malvern Instruments ⁾ , which is a commercially available zeta potential measuring device. A specific measurement method will be described later.

  Examples of the selection of water-soluble polysaccharides that can have the above properties include anionic polysaccharides such as propylene glycol alginate, high methoxyl pectin, carboxymethyl cellulose (CMC) and water-soluble soybean polysaccharides, and complex with proteins. The type is not limited as long as the body has the above zeta potential, and these can be used alone or in combination. In particular, the use of water-soluble soybean polysaccharide is preferable because of the high effect of reducing the surface charge of the protein, and the use of a polysaccharide that can be substituted with this is also preferable. In this case, other polysaccharides such as propylene glycol alginate, high methoxyl pectin, and CMC can be used in combination with the water-soluble soybean polysaccharide. It is also possible to substitute for the addition of water-soluble polysaccharides by mixing plant materials that are the source of these water-soluble polysaccharides with proteins or protein hydrolysates and extracting these polysaccharides during production. .

  The content of the water-soluble polysaccharide in the protein material varies depending on the type of the water-soluble polysaccharide, and can be appropriately set using the value of the zeta potential when complexed with the protein hydrolyzate as an index. The amount of dietary fiber is preferably 2% by weight or more, and more preferably 2.5% by weight or more. The upper limit is not particularly set, but is preferably 10% by weight or less, or 8% by weight or less. If the content is too low, the zeta potential due to the water-soluble polysaccharide is increased, the effect of reducing the unpleasant taste such as bitterness, savory taste, and sourness becomes poor, the effect of reducing the viscosity after heating is reduced, and further, the pH is 4-5. The dispersion stability at .5 decreases. On the other hand, if the content is too high, the protein content decreases and the viscosity of the aqueous dispersion before heating tends to increase, which is not desirable as a protein material.

  The water-soluble polysaccharide can be added by mixing in an aqueous system with an aqueous dispersion of the protein before enzymatic degradation or an aqueous dispersion of the hydrolyzed protein after enzymatic degradation. Moreover, it can also mix after making it aqueous solution beforehand. A person skilled in the art can appropriately determine the timing of adding the water-soluble polysaccharide in the production stage.

  The content of the water-soluble polysaccharide can be grasped with reference to the content of dietary fiber. For example, the content of water-soluble polysaccharide can be analyzed using an official method for measuring dietary fiber using an enzyme-weight method (modified Prosky method). it can.

(Composite of protein hydrolyzate and water-soluble polysaccharide)
As a means for reacting and hydrolyzing protein hydrolyzate and water-soluble polysaccharide, high-pressure homogenization method using a homogenizer or the like, or steam directly into an aqueous dispersion under high temperature and high pressure such as jet cooker or VTIS A method of performing a direct steam heat treatment apparatus such as a steam blowing type performed by injection can be applied.
In the case of the high-pressure homogenization method, the pressure can be set to 10 to 100 MPa, for example. When using a direct steam heat treatment apparatus, it is preferable to perform the treatment at 130 to 160 ° C. for 1 to 60 seconds. When the homogenization pressure is too low or the temperature of the heat treatment is too low, the complexation becomes insufficient and the protein material of the present invention cannot be obtained. For example, the compounding is insufficient only by heat treatment for sterilization purposes such as plate sterilization used in the production of general beverages.

(Phytic acid content)
When the protein material of the present invention is derived from a plant such as soybean, the phytic acid content may or may not be adjusted according to the quality and cost required of the product. When reducing the phytic acid content, such as acidic soluble soy protein, it may be treated with an enzyme such as phytase.

(Productization)
The protein material of the present invention can be appropriately adjusted to a pH of 2 to 10 during the production process as necessary to obtain a product with a desired pH. The obtained protein material may remain in a liquid state, but can be made into a final product in a powder form by spray drying or the like.
The obtained protein material preferably has an NSI (nitrogen solubility index) of 30 to 70.

(Viscosity of aqueous dispersion)
The protein material provided by the present invention is characterized by low viscosity before and after heating when blended at a high concentration. In quantifying this, the viscosity (20 ° C.) before and after heating at pH 7 of a 19 wt% aqueous dispersion in terms of protein was set as an index of low viscosity.
According to this, the protein material of the present invention has a viscosity before heating of 1000 mPa · s or less, more preferably 700 mPa · s or less, more preferably 500 mPa · s or less, more preferably 200 mPa · s or less, at 20 ° C. at a pH of 7, most preferably It may be characterized by a low viscosity of preferably 100 mPa · s or less.

Furthermore, the viscosity after heating a 19% by weight aqueous dispersion in terms of protein at 95 ° C. for 10 minutes at pH 7 is 1000 mPa · s or less, preferably 500 mPa · s or less, more preferably 200 mPa · s or less at 20 ° C. Can be low viscosity.
In other words, in the case of a commercially available protein material, if the concentration of the aqueous dispersion is 19% by weight, the viscosity increases rapidly before and after heating, or gels. On the other hand, the aqueous dispersion of the protein material of the present invention does not increase in viscosity before and after heating at pH 7, or is slow, and can maintain fluidity at low viscosity.
The protein material of the present invention desirably has a viscosity within the above range before and after heating even in a pH range other than pH 7.

  If the viscosity of the aqueous dispersion before heating is high, it tends to increase in viscosity when the protein material is blended in a high amount. For example, in powdered beverages, it adversely affects the flavor and texture, or is formulated in the manufacturing process of RTD beverages, etc. Since it becomes a problem in a stage, it is not preferable. In addition, if the viscosity before heating is low but the viscosity after heating is high, thickening or gelation is more likely to occur when the protein material is highly blended, and the temperature rise such as heat sterilization in the manufacturing process of RTD beverages etc. Since it becomes a problem in a process, it is not preferable.

  In the present invention, the viscosity of the aqueous dispersion is measured at a predetermined solution concentration and temperature using a B-type viscometer.

(Storage sedimentation rate of aqueous dispersion)
The protein material provided in the present invention may also be characterized in that the storage sedimentation rate of a 1% by weight aqueous dispersion in terms of protein at pH 4, pH 5 and pH 5.5 is 5% or less. Such properties are mainly brought about by the addition of the water-soluble polysaccharide.

That is, in the case of commercially available protein materials, when the aqueous dispersion is adjusted to such pH, the protein is separated and settled by isoelectric point precipitation, but the aqueous dispersion of the protein material of the present invention is at any pH. High dispersion stability can be maintained without the solids settling for a long time.
In the present invention, the storage sedimentation rate of the aqueous dispersion is measured as follows.
Prepare a 1% by weight aqueous dispersion in terms of protein, inject them into a test tube, leave at room temperature (20 ° C.) for 30 minutes, and then the ratio of the height of the supernatant to the total liquid height (%) Calculated as

(Heat resistance of aqueous dispersion)
The protein material provided by the present invention may be characterized in that, for example, in the case of a dilute dispersion such as 5% by weight or less, the protein is less likely to aggregate or settle due to heating. Having this feature leads to an advantage of exhibiting heat resistance with respect to the heat sterilization process that is essential when producing a beverage (particularly acidic).

(Features and usage of protein materials)
The main features of the protein material provided by the present invention are listed as follows.
(1) Even if it is blended at a high concentration, it has a low viscosity, and heat coagulation and gelation are hardly caused by heating, and heat resistance can be maintained.
(2) It has a good flavor with few unpleasant tastes such as bitterness and egg taste derived from the enzymatic degradation product of protein.
(3) Regardless of whether the pH of the food or drink is acidic or neutral, it can be easily dispersed in water. When used for foods and drinks, it is not necessary to pay attention to aggregation and sedimentation due to the isoelectric point of the protein contained in the protein raw material.
(4) Excellent dispersion stability in a liquid and little roughness.
(5) In a liquid having a low concentration (5% or less), aggregation and sedimentation are unlikely to occur even after heating under an acidic pH of 5 or less.

  From these features (1) to (5), it can be added to a wide range of pH foods and drinks. For example, RTD beverages such as soft drinks and jelly beverages, powdered beverages such as protein powder, gel foods such as fruit jelly and pudding, and liquid foods (including liquid, semi-solid and solid foods). Suitable for use. Although these foods and drinks have many acidic types, the protein material of the present invention can be used not only in neutral products but also in acidic products.

  The protein material of the present invention further has the following secondary features A to D, and it is possible to produce a characteristic applied food based on each feature.

(A) Reactivity with pectin One of the secondary features of the protein material of the present invention is its low reactivity with LM pectin and HM pectin, which are frequently used as stabilizers and gelling agents for foods and drinks. .
Usually, soy protein and milk whey protein have a high reactivity with pectin in an acidic region below the isoelectric point, causing a problem that aggregation occurs.
More specifically, protein materials derived from various animal and vegetable sources exist as protein materials added to general processed foods. In general, casein and soy protein have their own isoelectric points. At a pH near the point (around pH 4.5), the solubility is lowered and they themselves aggregate. Further, even milk whey protein that is soluble at an acidic pH causes an electrical reaction and aggregation in an acidic solution in the presence of pectin. Therefore, proteins that can be used in acidic gel foods to which pectin is added are limited to collagen peptides having an amino acid score of 0 and a low nutritional value.
On the other hand, the protein material of the present invention is characterized in that it does not aggregate even when heated in the presence of pectin, and can be used in combination with pectin in various foods and drinks without paying attention to the interaction with pectin. Can be blended.

(Acid gel food)
By using the protein material of the present invention, it is possible to obtain a high-protein acidic gel-like food in which pectin is used as a gelling agent or stabilizer.
Pectin is classified into HM pectin (high methoxyl pectin) having a DE (degree of esterification: ratio of methyl esterified galacturonic acid) of 50% or more and LM pectin (low methoxyl pectin) having a DE of less than 50%. The The protein material of the present invention can be used for acidic gel foods using any of these pectin.
Gels using HM pectin can generally be prepared by increasing the sugar content (Brix) of a solution containing HM pectin by evaporating water and adjusting it to acidic pH.
In addition, a gel using LM pectin can be prepared by reacting a divalent metal ion such as calcium ion with LM pectin in a solution containing LM pectin and gelling it. Using this property, the gel can also be prepared by mixing a solution of LM pectin and a food with high calcium content such as milk.

○ Acid gel food using LM pectin As an embodiment of the acid gel food in the present invention, LM pectin and divalent metal ions are mixed and gelled by these reactions. By adding the protein material of the present invention to the acidic gel food, the LM pectin reacts with the protein in the liquid being produced, and the high protein acidic gel food using LM pectin is used without aggregation. Can be manufactured.

For example, LM pectin, a protein material, an acidifying agent such as acidulant or fruit juice, and, if necessary, a solution containing other raw materials such as sugars and fragrances are prepared and mixed with divalent metal ions. And can be produced by gelation. The pH of the solution containing LM pectin and the protein material is 3 to 5, preferably 3 or more and less than 4.5.
In this case, the solution is generally prepared while heating at 80 ° C. or higher in order to dissolve LM pectin.
However, in the case of cold water soluble LM pectin (for example, “UTFC LM QS 400C” (manufactured by Unitech Foods Co., Ltd.), it can be prepared even at a water temperature of 30 ° C. or less. In this case, all raw materials including divalent metal ions can be prepared. Can be mixed in advance with a powder and dissolved in water and gelled to obtain an acidic gel food.

  The amount of LM pectin added is an item that is appropriately adjusted according to the texture and physical properties required of the acidic gel food to be produced, but is preferably 0.2 to 3% by weight in the acidic gel food. Examples of the divalent metal ion include calcium and magnesium. A divalent metal ion-containing material containing these, that is, a salt of the divalent metal ion or a food such as milk containing the divalent metal ion can also be used.

Moreover, although the addition amount of a protein raw material is a matter adjusted suitably according to the nutritional value of the protein calculated | required by the acidic gel food to manufacture, 2-20 weight% is preferable as protein amount in acidic gel food, 4-15 Weight percent is more preferred.
The pH of the obtained acidic gel food is suitably 3 or more and less than 7, preferably 3.5 to 6.5, more preferably 3.5 or more and less than 6.
Using this acidic gel food as a constituent part, it is also possible to produce an application product of acidic gel food in various combinations with other liquids, jelly, whipped cream, fruit, nata de coco and the like.

・ Liquid base for acidic gel foods By using the protein material of the present invention, it contains LM pectin, the protein material, acidifying agents such as acidulant and fruit juice, and other raw materials such as sugars and fragrances as necessary. Producing a liquid base for acidic gel food, and aseptically filling a sealed container to provide it, so that the consumer mixes the liquid base with milk containing divalent metal ions at home, etc. It is also possible to easily prepare a high protein acid gel food using pectin. Furthermore, the acidic gel-like liquid base for food of the present invention can be made into a stable emulsification system by containing fats and oils by containing protein. Therefore, functional fats and oils such as medium chain fatty acids and polyunsaturated fatty acids can be added, and an acidic gel food excellent in nutritional balance can be prepared.

Acid gel food preparation set For the same purpose, the above-mentioned sealed container filled aseptically in a sealed condition, the base for acid gel food filled in a sealed container, and a sealed container packed divalent metal ion packed in another sealed container Or it can also be provided as an acidic gel food preparation set in combination with its contents.

・ Powder base for acidic gel foods By using the protein material of the present invention, an acidifying agent such as cold water soluble LM pectin, the protein material, divalent metal ions, acidulant and fruit juice powder, and other sugars if necessary And by mixing other raw materials such as fragrances, oils and fats mentioned above to produce a powder base for acidic gel foods, by providing this, the consumer dissolves the powder base in water, milk, etc. at home, It is also possible to prepare a high protein acid gel food using LM pectin. Thus, the consumer does not need to dissolve LM pectin in hot water in advance, and can simply prepare and eat the gel food by simply adding water and stirring.
At this time, the divalent metal ion is preferably slowly soluble (slowly acidic and soluble property) so that the divalent metal ion reacts with the LM pectin after the cold water soluble LM pectin is first dissolved. Calcium sulfate, tricalcium phosphate and calcium carbonate are preferred.

○ Acid gel food using HM pectin As another embodiment of the acid gel food in the present invention, there is a so-called “pectin jelly” using HM pectin. Pectin jelly dissolves raw materials containing HM pectin and saccharides in water, heats it to 100 ° C or higher to evaporate water to 30% by weight or less, and adds acid such as acidulant or fruit juice to this to adjust the pH to 3 It can manufacture by making it acidic. By adding the protein material of the present invention to the pectin jelly, HM pectin and protein do not react and aggregate in the liquid being produced, and a high protein pectin jelly can be produced.
The acidic gel food is preferably 10 to 40% by weight of protein, 30 to 80% by weight of carbohydrate, and preferably 3 to 4 in pH. The content of HM pectin is preferably 1 to 10% by weight. Since the protein material of the present invention can be blended in place of carbohydrates, it is possible to provide a pectin jelly with a lower sugar and an excellent nutritional balance of high protein.

(B) Hydration at low hydration One additional characteristic of the protein material of the present invention is that it is hydrated at a low hydration amount (eg, 1 to 1.5 times the amount) and easily pasted. It is possible to do. This means that it is as hydratable as flour. Therefore, it is possible to provide a food dough having little change in physical properties such as hardness over time of the hydrated dough and having little roughness.
Conventional protein materials such as isolated soy protein have very high water retention, so adding a large amount to a dough such as baked confectionery needs to increase the amount of water excessively, so the baking time must be lengthened, There was a problem that only the surface of the baked confectionery burned and the inside was insufficiently baked.

In contrast, since the protein material of the present invention has low water retention, there are few such problems, and the baking time can be greatly shortened and the baking process can be stabilized.
In addition, since conventional protein materials have high water absorbency, if they are kneaded in powdered form in candy or chocolate, or blended with baked confectionery, saliva is taken away in the mouth during eating, and the lubricity in the mouth decreases significantly. It is easy to feel uncomfortable feeling like eating okara. On the other hand, the protein material of the present invention has a property of low water absorption, does not take too much saliva in the oral cavity, has little decrease in oral lubricity, and improves the above-mentioned discomfort Has been.

  That is, since the protein material of the present invention has properties similar to flours such as wheat flour, various foods in which they are used, such as baked confectionery (cookies, biscuits, sponge cakes, protein bars, etc.), breads, etc. It can be used as an alternative to flour. In addition, due to the above features, it can be used for kneading into chocolates, soft candy, nougat and the like.

(C) Features of oil-absorbing property and applications using the same Another secondary feature of the protein material of the present invention is that the oil-absorbing property of the powder is high. For example, with respect to 1 part by weight of powder, at least 0.5 parts by weight of oil (which is liquid when mixed regardless of the melting point) can be absorbed, and 1 part by weight or less, preferably 0.8 parts by weight or less. Oil can be absorbed. Oil absorption here refers to a state in which the powder holds oil and fat and the powder is in a continuous phase. Therefore, it is not in a state where the oil and fat oozes out of the powder and the oil and fat is in a continuous phase. High oil absorbency means that the weight of fats and oils that can be absorbed by the powder is large.

Oils and fats can be pulverized using the high oil-absorbing property of the protein material of the present invention. For example, fats and oils having low oxidation stability can be adsorbed to enhance storage stability, and seasoning oil can be adsorbed and used as powdered fats and oils. In addition, in the oil-absorbed state, utilizing the hydration property with low water content described above, hydrating by adding a small amount of water, and using an emulsifier such as a homogenizer by properly stirring with a spatula or the like And a high concentration O / W emulsion can be easily prepared. For example, it is possible to prepare an O / W emulsion having a high protein and a high oil content such as powder: oil: fat: water = 1: 1: 1.

  Utilizing this property, it becomes possible to simplify the production method of caramel, mayonnaise, ganache-like chocolate cream, etc. based on a high concentration O / W emulsion, or to increase the protein and nutrition of these. . Furthermore, by applying it to the production of medical foods such as concentrated liquid foods (liquid / semi-solid) and high-nutrition jelly, these can be produced more easily than before.

(D) Improvement of salt tolerance Another secondary feature of the protein material of the present invention is that the salt resistance of the aqueous dispersion is improved. In general, when an alkali metal salt (for example, sodium salt, potassium salt, calcium salt, magnesium salt, etc.) that becomes water-soluble is added to an aqueous solution of whey protein or acidic soluble soy protein in the acidic region, it is particularly agglomerated and coagulated by heat treatment. Is likely to occur. For this reason, when it is going to manufacture by highly blending protein in acidic concentrated liquid food (liquid and semi-solid) and high nutrition jelly, there are various restrictions on the manufacturing process and quality.

  Therefore, in order to avoid these problems, conventionally, efforts have been made to use a combination of gelatin, collagen peptide, milk peptide, soybean peptide, amino acids and the like having high salt resistance. However, gelatin and collagen peptides are expensive, the amino acid score is 0, which is insufficient for applications that place importance on amino acid balance, milk peptides, soy peptides and amino acids are expensive, and bitterness derived from peptides The protein material of the present invention that has an amino acid score of 1.0 and has salt resistance and excellent flavor has high utility value because there are restrictions on flavor such as unpleasant taste derived from amino acids and amino acids.

(Measuring method)
The analysis value in the present invention is determined according to the following measurement method.
○ Average molecular weight
After subjecting the protein degradation product solution diluted with 50 mM phosphate buffer (1% (weight / volume) SDS, 1.2% (weight / volume) NaCl, pH 7.0) to sonication for 10 minutes, Filter using a 0.2 μm filter. Flow rate of the resulting filtrate 0.4 ml / min, at room temperature 20 ° C., "TSK gel ^(R) G3000SWXL column" and "TSK gel ^(R) G2000SWXL column" (both Tosoh Corp., Column size: inner diameter 7.8 mm × length 30 cm) in series, and the protein degradation product is eluted using the above phosphate buffer. Proteolytic products are detected by measuring absorbance at 220 nm using a UV detector. Thus, the weight average molecular weight of the proteolysate separated and purified in each fraction is calculated from a chart obtained using GPC software (manufactured by Tosoh Corporation).

As the molecular weight marker, the following molecular weight compounds are used.
335,000 (Thyrogloblin, manufactured by Wako Pure Chemical Industries, Ltd.)
150,000 (γ-globlin, manufactured by Wako Pure Chemical Industries, Ltd.)
67,000 (Albumin (BSA), manufactured by SIGMA)
43,000 (Peroxidase, Wako Pure Chemical Industries, Ltd.)
18,000 (Myoglobin, manufactured by SIGMA)
12,384 (Cytochrome-C, manufactured by SIGMA)
5,734 (Insulin, manufactured by SIGMA)
307 (Glutathione, manufactured by Wako Pure Chemical Industries, Ltd.)
137 (p-aminobenzoic acid, manufactured by Wako Pure Chemical Industries, Ltd.)

○ Zeta potential A 0.1% by weight aqueous solution of protein material is used as a sample, and "Zetasizer ^(R) Nano ZS" (manufactured by Malvern Instruments ⁾ is used as the measurement device. With the attached automatic titrator "MPT-2" The range of pH 2-7 is continuously measured in 0.5 increments. The pH is adjusted using 0.25M sodium hydroxide and 0.25M hydrochloric acid. For data processing, zeta potential curves are obtained using the attached software.

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

■ Comparative Example 1 (Preparation of protein degradation product)
Undecomposed product is a soy protein isolate "Fujipuro ^(R) F '(Fuji Oil Co., Ltd., protein content: 90.8% dry basis) dissolved in 10% (pH 7.1) and warmed to 40 ° C. In the state, the amount of protease and the reaction time of the commercial product are changed and hydrolyzed. After the reaction, the pH is adjusted to 7 and sterilized by heating, followed by spray drying. Seven kinds of protein hydrolysates (af) Got. Degradation degree (0.22M TCA solubility) of the obtained hydrolyzate was a: 20%, b: 25%, c: 30%, d: 45%, e: 55%, f: 75%, respectively. Met. Moreover, the nitrogen solubility index (NSI) of these hydrolysates was 91, 90, 72, 50, 59, 78, respectively.

○ Relationship between degree of degradation and viscosity Prepare a solution of protein hydrolyzates a to f of each degree of degradation at a protein concentration of 19%, and use a B-type viscometer to measure the viscosity at 20 ° C. before and after heat treatment for 10 minutes in boiling water Measured. Table 1 shows the results.

(Table 1)

  When a 19% protein concentration solution was prepared, when the degree of degradation was 25% or less, the viscosity exceeded 1,000 mPa s even before heating, and the viscosity increased significantly due to heating, making handling very difficult. Further, when the degree of degradation was 30% or more, the viscosity before and after heating tended to decrease, but the protein hydrolysates c and d still had a significant increase in viscosity after heating.

○ Relationship between degree of degradation and unpleasant taste Prepare a simple powdered beverage (7% granulated sugar, pH 5.0) containing 5% protein hydrolyzate a to f of each degree of degradation as protein concentration, and ask 10 panelists The unpleasant taste was evaluated by summing up the bitterness and the taste. Evaluation standards for unpleasant taste are 1 (no unpleasant taste), 2 (slightly unpleasant taste), 3 (have unpleasant taste), 4 (strong unpleasant taste), 5 (very unpleasant taste) The average value of the evaluation given by each panel was calculated in five stages. Table 2 shows the results.

(Table 2)

As shown in Table 2, when the degree of decomposition was 30% or more, particularly 55% or more, the bitterness due to hydrolysis was exhibited, and the higher the degree of decomposition, the stronger the bitterness. Therefore, it was a quality that was difficult to use in terms of flavor. Further, when HMF, which is an insoluble fraction, was separated from the hydrolyzates a to f, the amount of relatively low-molecular peptides increased and the degree of degradation increased, so that the bitter taste was felt even stronger.
Therefore, from the above results, the protein hydrolyzate having a degradation degree of 55% or more shows good processability at a high protein concentration, but the bitterness derived from the enzyme degradation product becomes stronger as the degradation degree increases and is difficult to use. There was a trend.

○ Dispersion stability at pH 4 to 5.5 A 1% protein concentration solution is prepared for soy protein hydrolyzate, pH is adjusted in 0.5 increments to pH 4 to 6.5 in dilute sodium hydroxide or hydrochloric acid, and each The state of the solution after standing at room temperature at 20 ° C. for 30 minutes at pH was observed.
As soy protein materials, commercial product A (0.22 MTCA rate 25%), commercial product B (35%), commercial product C (50%), commercial product D (acid-soluble soy protein, 15%) used. All of these contain HMF generated during enzymatic degradation.
Dispersion stability was evaluated by observing the state of the solution after standing for 30 minutes, in a state without a supernatant (○), with a slight supernatant (△), completely with a supernatant, insoluble The state (x) in which the thing was formed was evaluated. The results are shown in Table 3.

(Table 3) Dispersion stability evaluation

As shown in Table 3, in any hydrolyzate of any degree of degradation, the protein was in an unstable state at pH 4.0 to 5.5, suggesting that the use in this region is limited. This is considered to be due to the fact that the soy protein has the lowest solubility in the vicinity of the isoelectric point (pH 4.5 to 5.5).
Therefore, even at high protein concentrations, low viscosity before and after heating, high processability, little bitterness derived from degradation products, and practically stable dispersion even near the isoelectric point (4.5-5.5) of soy protein Soy protein hydrolyzate could not be obtained in this experiment.

■ Example 1 (Production of protein material of the present invention)
Soy protein hydrolyzate d obtained in Comparative Example 1 (protein content: 90.8% per dry matter, degree of degradation 45%, HMF non-separable type, weight average molecular weight about 20,000) and 10 parts of water-soluble polysaccharide 1 part of soybean polysaccharide “Soya Five ^(R) S” (manufactured by Fuji Oil Co., Ltd., hereinafter referred to as “SSPS”) was sufficiently dispersed in 89 parts of warm water at 80 ° C. This dispersion was subjected to a heat treatment (140 ° C., 10 seconds) using a direct steam blowing type heating device (manufactured by Alpha Val) and spray-dried to obtain the protein material of the present invention. When the water solubility of the obtained protein material at pH 3.5, pH 4.5, pH 5.5 and pH 7 was measured, it was 49%, 48%, 50% and 50%, respectively, and all were 30 to 70%. It was an intermediate and flat water dissolution rate.

Further, the zeta potentials of the protein material at pH 2, pH 3, and pH 6 were 3.8 mV, 2.0 mV, and −18 mV, respectively, and at pH 2 to 3, all were positive potentials with a very low absolute value of 5 mV or less. And in pH 6, it was -10 to -20mV, and was a negative potential with a comparatively low absolute value.
On the other hand, the zeta potential of the soy protein hydrolyzate d of Comparative Example 1 at the pH was 25 mV, 16 mV, and −29 mV, respectively, and at pH 2 to 3, all were positive potentials with a high absolute value exceeding 15 mV. And in pH 6, it was far below -20mV, and was a negative potential with a comparatively high absolute value. That is, for the protein material obtained in Example 1, it was found that the effect of the change in pH on the water solubility and the zeta potential was relatively gradual.

  Quality evaluation was performed on the sample obtained in Example 1 and the sample prepared without adding the water-soluble polysaccharide by the same method as these for comparison. In the method described in Comparative Example 1, the viscosity of a solution at 20 ° C. before and after heating at a protein concentration of 19%, the flavor of a simple powdered beverage containing 5% as the protein concentration, and the pH of the protein concentration 1% solution at pH 4 to 6.5 Each of the dispersion stability was evaluated. Evaluation of dispersion stability was performed by visually observing the sedimentation state of the protein in the same manner as in Comparative Example 1, and further by measuring the storage sedimentation rate in comparison with Comparative Example 1. The results are shown in Tables 4 and 5.

(Table 4) Viscosity and flavor before and after heating

(Table 5) Dispersion stability at each pH

  From the results shown in Table 4, the bitterness is significantly reduced despite the low viscosity before and after heating at a protein concentration of 19%, and the soy protein is stably dispersed even near the isoelectric point (pH 4.5 to 5.5). Since the property is high, the problem of the high protein blended food and drink that the conventional protein materials had was improved.

■ Example 2 (LM-pectin-containing acidic gel food liquid base)
A liquid base for acidic gel foods containing LM pectin was prepared according to the formulation shown in Table 6 below. The protein material, granulated sugar and LM pectin obtained in Example 1 were added and dissolved while boiling the liquid sauce containing fruit juice at 80 ° C. and propeller stirring. Stirring was continued at 80 ° C. for 10 minutes, a fragrance was added, and a sauce part was prepared. The pH of this solution was 3.5. The solution was then filled into a container, sealed, and sterilized at 80 ° C. for 5 minutes to obtain a liquid base for acidic gel food. Although this liquid base contained about 6% of protein, aggregation of LM pectin and protein did not occur, and the liquid base maintained stable quality.

(Table 6)

  When the obtained acidic gel food liquid base and milk were mixed at a ratio of 1: 1, the LM pectin in the liquid base and calcium in the milk reacted to have high protein and moderate shape retention, An acidic gel food with a texture comparable to that prepared from a liquid base for an acidic gel food based on carbohydrates could be prepared.

■ Comparative Example 2
In the formulation of Table 6, instead of the protein material in Example 1, isolated soybean protein "Fujipuro ^(R) F '(Fuji Oil Co., Ltd.) and separated milk whey protein" PROVON ^(R) 190 "(Glanbia Nutritionals An acid gel food liquid base was prepared in the same manner as in Example 2.
However, in the case of using the soy protein isolate, since the soy protein isolate is difficult to dissolve in the acidic solution, aggregation occurs before heating, and a uniform acidic gel food liquid base cannot be obtained.
In addition, milk whey protein dissolved without problems during preparation, but agglomeration occurred after heating, and a uniform acidic gel food liquid base could not be obtained.
The isolated soy protein has an isoelectric point in the vicinity of pH 4.5, low solubility under acidic conditions, and milk whey protein dissolves under acidic conditions, but is considered to be caused by reaction with LM pectin by heating. .

■ Example 3 (LM-pectin-containing acidic gel food powder base)
5 g of the protein material of Example 1, 3.5 g of peach and grapefruit juice powder mix, 2.6 g of cold water soluble LM pectin “UTFC LM QS 400C” (manufactured by Unitech Foods Co., Ltd.), 5 g of sugar, tricalcium phosphate 32 g of powder was mixed, and an acid gel food powder base containing LM pectin was prepared.
The powder base was dissolved in 100 g of water with stirring (pH 4.7) and allowed to stand for 5 minutes to gel, and a high-protein acidic gel food (mousse) having a protein content of about 4% could be obtained. .

■ Example 4 (high sugar acid gel food containing HM pectin)
A high-sugar acid gel food blended with HM pectin was prepared as shown in Table 7 below.
Water and a small amount of antifoaming agent were put in a heating kettle in advance, and then the raw material A group was mixed with powder and heated up while stirring. It was confirmed that the HM pectin was dissolved at 80 to 90 ° C., and then the raw material B group was mixed and charged. Furthermore, the raw material C group was added, and water was sufficiently evaporated at 100 ° C. or higher. When the sugar content exceeded 80% with a Brix meter, the raw material D group was added to adjust the pH to 3.5, the heating was stopped, the mold was poured into the mold, the mold was cooled, and the mold was removed to obtain a high protein pectin jelly.

(Table 7)

■ Comparative Example 3
In the formulation of Table 7, instead of the protein material Preparation Example 1, isolated soybean protein "Fujipuro ^(R) F '(Fuji Oil Co., Ltd.) and separated milk whey protein" PROVON ^(R) 190 "(Glanbia Nutritionals Pectin jelly was prepared in the same manner as in Example 4.
However, pectin jelly could not be prepared with these formulations due to the same phenomenon as in Comparative Example 2.

Claims (15)

A protein material that satisfies the following requirements 1 to 4.
1. The protein content per dry matter is 50% by weight or more,
2.0.22M TCA solubility is 30-70%,
3. Water solubility at pH 3.5, pH 4.5 and pH 5.5 are all 30-70%,
4). Contains a water-soluble polysaccharide so that the zeta potential of the aqueous dispersion of the protein material is -10 to 20 mV at pH 2-3. Furthermore, the protein raw material of Claim 1 whose water solubility in pH7 is 30 to 70%. The protein material according to claim 1, wherein the viscosity at pH 7 of the 19 wt% aqueous dispersion in terms of protein is 1000 mPa · s or less at 20 ° C. The protein material according to claim 3, wherein the viscosity of the 19% by weight aqueous dispersion in terms of protein after heating at 95 ° C for 10 minutes at pH 7 is 1000 mPa · s or less at 20 ° C. The protein material according to claim 1, wherein the 1% by weight aqueous dispersion in terms of protein has a storage sedimentation rate of 5% or less at pH 4, pH 5 and pH 5.5. A protein hydrolyzate having a 0.22M TCA solubility of 30 to 70% and a water-soluble soybean polysaccharide, the protein hydrolyzate and the water-soluble soybean polysaccharide are complexed, and the protein content per dry matter Is a protein material characterized in that it is 50% by weight or more. The protein material according to claim 6, wherein the protein hydrolyzate is derived from soybeans. The manufacturing method of the protein raw material characterized by having the following process.
1. The aqueous dispersion containing protein is hydrolyzed with a proteolytic enzyme so that the 0.22M TCA solubility is 30 to 70%, and a protein hydrolyzate containing insoluble protein produced by the decomposition treatment is obtained. Obtaining step,
2. A step of mixing a protein or protein hydrolyzate and one or more water-soluble polysaccharides in an aqueous system, wherein the water-soluble polysaccharides have a zeta potential of an aqueous dispersion of the protein material at a pH of 2 to 3. All are water-soluble polysaccharides that are -10 to 20 mV,
3. Process for conjugating protein hydrolyzate and water-soluble polysaccharide An acidic gel-like food gelled with pectin and reinforced with protein, wherein the protein material according to any one of claims 1 to 7 is used as the protein. The acidic gelled food according to claim 9, wherein the acidic gelled food is gelled by a reaction between LM pectin and divalent metal ions. The method for producing an acidic gelled food according to claim 10, wherein a solution containing LM pectin and the protein material and a divalent metal ion are mixed and gelled. A liquid base for an acidic gel food containing LM pectin and a protein material for preparing an acidic gel food by mixing with a divalent metal ion and gelling, wherein the protein material is a protein base. A liquid base for acidic gel food, wherein the protein material according to any one of the above is used. A liquid base for an acidic gel food packaged in a sealed container containing LM pectin and the protein material according to any one of claims 1 to 7 for preparing an acidic gel food product by mixing with a divalent metal ion and gelling. And a set for preparing an acidic gel food, characterized in that a divalent metal ion in a sealed container or a combination thereof is combined. A cold water-soluble LM pectin for preparing an acidic gel food by mixing with a divalent metal ion and gelling, the protein material according to any one of claims 1 to 7, and a divalent metal ion A powder base for acidic gel foods. The acidic gel food according to claim 9, wherein the pectin is HM pectin, the protein is 10 to 40% by weight, the carbohydrate is 30 to 80% by weight, and the pH is 3 to 4. An acidic gel food characterized by