Method for producing iron-containing protein composition

Abstract

To provide a method for producing a novel iron-containing protein composition solution that is economical and simple, yet suppresses the occurrence of precipitation and does not exhibit the astringent taste peculiar to iron.SOLUTION: A method for producing iron-containing composition, including a step of preparing a protein-containing solution containing at least one of carbonate ion and bicarbonate ion, and a protein, and a step of adding iron to the protein-containing solution.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing an iron-containing protein composition.

Background Art

[0002] Iron is important for maintaining homeostasis in the body and can be said to be one of the nutrients that must be ingested carefully in terms of diet. The recommended daily intake of iron for adult women is 6.0 - 6.5 mg / day (without menstruation) and 10.5 mg / day (with menstruation) (Ministry of Health, Labour and Welfare, Dietary Intake Standards for Japanese in 2015 Edition). In contrast, the average iron intake of women aged 20 - 39 is only 6.4 mg / day (Ministry of Health, Labour and Welfare, National Health and Nutrition Survey in 2017), and iron deficiency has been pointed out in young and middle-aged women. Many people with iron deficiency or anemia tendency among young and middle-aged women often take iron in the form of foods or medicines fortified with iron, such as iron supplements.

[0003] However, inorganic irons such as iron citrate, iron pyrophosphate, and iron sulfate, which are generally used as iron supplements, may have astringent or metallic tastes unique to iron, or may have side effects such as irritating the gastrointestinal tract or mucous membranes. In addition, heme iron, which is organic iron, has high absorbability but has problems such as a metallic taste and a fishy smell. Therefore, when adding these iron supplements to foods or using them as iron supplements, the added amount must be limited, and in many cases, it is insufficient to achieve the required intake.

[0004] On the one hand, as iron-containing proteins, an iron-lactoferrin complex (Japanese Patent Laid-Open No. 7-304798), an iron-casein complex (Japanese Patent Laid-Open No. 9-77793), an iron-whey protein hydrolyzate complex (Japanese Patent Laid-Open No. 2000-50812), etc. are known in the form of compositions. These iron-containing protein compositions have no astringent taste or metallic taste peculiar to iron, no side effects, and furthermore, have good solubility and thermal stability, so they are suitable for use in foods and drinks and iron preparations. Further, Japanese Patent Laid-Open No. 2002-000225 aims to provide an iron-containing protein composition solution in which the generation of precipitation during freezing and thawing is suppressed, and further to provide a frozen product of the solution useful for iron fortification of foods and drinks and the production of iron preparations and a thawed solution of the frozen product. As a solution means, the iron-containing protein composition is dissolved in the aqueous medium as particles having an average particle diameter of 200 nm or less, has a pH of 5 to 10, and at least one selected from the group consisting of monosaccharides, disaccharides, sugar alcohols, non-reducing sugars, and dextrins. Further, the iron-containing protein composition further contains carbonic acid and / or bicarbonate. An iron-containing protein composition solution and a method for preparing an iron-containing protein composition solution are disclosed.

Prior Art Documents

Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 7-304798 Patent Document 2: Japanese Patent Laid-Open No. 9-77793 Patent Document 3: Japanese Patent Laid-Open No. 2000-50812 Patent Document 4: Japanese Patent Laid-Open No. 2002-000225

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the production methods of the iron-containing protein composition solutions disclosed in Patent Documents 1 to 4 had problems in terms of economy. Further, there has been a demand for a simple production method of an iron-containing protein composition solution in which the generation of precipitation is suppressed and which does not exhibit an astringent taste peculiar to iron. Therefore, there has been a demand for a novel method for producing an iron-containing protein composition solution that is economical and simple, suppresses the generation of precipitation, and does not exhibit the astringent taste unique to iron.

Means for Solving the Problems

[0007] The present invention provides an invention including the following configurations as means for solving the above problems. [1] A method for producing an iron-containing composition, including a step of preparing a protein-containing solution containing at least one of carbonate ions and bicarbonate ions and a protein, and a step of adding iron to the protein-containing solution. [2] The method for producing an iron-containing composition according to [1], wherein in the step of adding iron, divalent iron in powder form is added to the protein-containing solution while stirring the protein-containing solution. [3] The method for producing an iron-containing composition according to [1], wherein in the step of adding iron, an iron-containing aqueous solution in which divalent iron is dispersed in an aqueous solvent is added to the protein-containing solution. [4] The method for producing an iron-containing composition according to any one of [1] to [3], wherein the addition amount of iron is 100 mM or less. [5] The method for producing an iron-containing composition according to any one of [1] to [4], wherein the pH of the protein-containing solution is 5 to 10. [6] The method for producing an iron-containing composition according to any one of [1] to [5], wherein the molar concentration of the protein is 1 / 1000 or more of the molar concentration of carbonate ions and / or bicarbonate ions. [7] The method for producing an iron-containing composition according to any one of [1] to [6], wherein the protein is whey derived from milk.

Effects of the Invention

[0008] According to the present invention, there is provided a method for producing a novel iron-containing protein composition solution that is economical and simple, suppresses the generation of precipitation, and does not exhibit the astringent taste unique to iron.

Modes for Carrying Out the Invention

[0009] (Method for Producing Iron-Containing Protein Composition) (Material) (Iron) For the iron used in the preparation of the iron-containing protein composition, divalent inorganic iron and / or trivalent inorganic iron can be used, but it is preferable to use divalent inorganic iron, and it is more preferable to use powdered divalent inorganic iron. Examples of divalent inorganic iron include ferrous sulfate, ferrous lactate, ferrous gluconate, sodium ferrous citrate, etc., and ferrous sulfate can be exemplified as a powdered one. Examples of trivalent inorganic iron include ferric chloride, ferric sulfate, ammonium ferric citrate, ferric citrate, etc.

[0010] (Protein) Examples of the protein used in the preparation of the iron-containing protein composition include lactoferrins, casein proteins, whey proteins, etc., and one or more of these can be used. Lactoferrins include lactoferrin separated from secretions such as milk of mammals such as humans and cows, transferrin separated from blood, organs, etc., ovotransferrin separated from eggs, etc., and lactoferrins obtained by decomposing these lactoferrins with enzymes. Casein proteins include casein, acid casein, sodium caseinate, calcium caseinate, α-casein, β-casein, κ-casein, etc. separated from secretions such as milk of mammals such as humans and cows, and casein proteins obtained by decomposing these caseins with enzymes. Whey proteins include WPI (Whey Protein Isolate) and WPC (Whey Protein Concentrate), which are whey proteins separated from secretions such as milk of mammals such as humans and cows, and those obtained by decomposing these whey proteins with enzymes. Examples include those obtained by decomposing the components separated from whey protein into β-lactoglobulin, α-lactalbumin, etc. with enzymes. Although numerous methods for separating large quantities of these proteins described above are already known, they can be separated by any method. They may also be produced from microorganisms, animal cells, or transgenic animals by genetic engineering.

[0011] When using a mixture of α-casein, β-casein, and κ-casein such as crude casein as the casein protein, the average molecular weight can be determined from its composition ratio, and based on this, the molar concentration of the dissolved casein can be calculated. Also, when using a mixture of various protein components as the whey protein, the average molecular weight can be determined from the composition ratio of each component, and from this value, the molar concentration of the dissolved whey protein can be calculated.

[0012] On the other hand, to obtain enzymatic hydrolysates of lactoferrins, casein proteins, and whey proteins, proteolytic enzymes can be used. As this proteolytic enzyme, enzymes of animal origin such as trypsin, chymotrypsin, and pepsin, enzymes of plant origin such as papain, bromelain, and ficin, and enzymes of microbial origin such as mold, bacteria, and yeast can be used. Examples of the form of the enzyme when the enzyme acts on the protein include isolated and purified enzymes, crude enzymes, cultures of microorganisms having the enzyme, culture solutions containing the enzyme from which the cells have been removed, microbial cells or disrupted cell masses, and genetically engineered protein hydrolases. As this enzyme, those prepared from various materials or commercially available enzyme preparations can be used. As this hydrolyzate, for example, those in which the molecular weight of the decomposition products is distributed in the range of 10,000 or less are preferred.

[0013] (Carbonic acid / bicarbonate) Carbonic acid and bicarbonate used in the preparation of the iron-containing protein composition include bicarbonates such as sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, and ammonium bicarbonate, and carbonates such as sodium carbonate, potassium carbonate, ammonium carbonate, and calcium carbonate. In addition, blowing in gaseous carbon dioxide, using a solution added with liquid or solid carbon dioxide, carbonated water, etc. may also be used.

[0014] (Method for producing an iron-containing protein composition) Specific embodiments of the production method of the present invention will be described below. (1) Preparation of a solution containing carbonic acid and / or bicarbonate and a protein Using the above-described materials, a solution containing carbonic acid and / or bicarbonate and a protein is prepared. The concentration of carbonate ions and / or bicarbonate ions (the total amount when both are contained) is more preferably 1000 mM or less, more preferably 500 mM or less, still more preferably 250 mM or less, and most preferably 100 mM or less. The concentration of the protein is preferably 20 mM or less, more preferably 10 mM or less, still more preferably 5 mM or less, and most preferably 2.5 mM or less. (2) Addition of iron 1) Stirring The solution containing carbonic acid and / or bicarbonate and a protein is stirred. Stirring is performed using a stirring blade, a magnetic stirrer, etc. In addition, instead of a stirring blade, a magnetic stirrer, etc., stirring by aeration may be used, or a combination of stirring by a stirring blade, a magnetic stirrer, etc. and aeration may be used. 2) Addition of iron A solution containing carbonic acid and / or bicarbonate and a protein is stirred, and powdery divalent inorganic iron is added thereto, followed by further stirring. By performing such an operation, the added divalent inorganic iron is oxidized while being dispersed in the solution by stirring, so that trivalent iron ions can be generated without uneven distribution in the solution. Thereby, a soluble complex containing iron-carbonate-protein can be efficiently produced. Further, stirring suppresses coarsening of the soluble complex containing iron-carbonate-protein. Therefore, the stirring time and the stirring intensity may be appropriately adjusted according to the size and shape of the tank so that the oxidation of divalent iron proceeds. The stirring time is preferably 1 minute or more, more preferably 5 minutes or more, and most preferably 10 minutes or more. The stirring intensity (rotation speed) is preferably 100 rpm or more, more preferably 500 rpm or more, and most preferably 1000 rpm or more. In addition, instead of the above-mentioned powdery divalent inorganic iron, a dispersion of divalent inorganic iron in a small amount of liquid such as water can be used, or this can be used in combination with the powdery divalent inorganic iron. When a solution containing carbonic acid and / or bicarbonate and a protein is added later to solid iron or a solution containing iron, the protein that has come into contact with high-concentration iron aggregates, and the iron-containing protein composition becomes unstable, which is not preferable. Therefore, when using trivalent iron, it is preferable to prepare a trivalent iron solution and add this to a solution containing carbonic acid and / or bicarbonate and a protein.

[0015] The addition amount of iron is preferably 100 mM or less, more preferably 50 mM or less, still more preferably 25 mM or less, and most preferably 12.5 mM or less.

[0016] (Molar concentration ratio) The ratio of the addition amounts of carbonic acid and / or bicarbonate, protein, and iron ions is preferably such that the molar concentration of carbonic acid and / or bicarbonate is 1 / 100 or more of the molar concentration of the protein, more preferably 1 / 50 or more, and most preferably 1 / 20 or more. The molar concentration of iron ions is preferably 1 / 100 or more, more preferably 1 / 50 or more, and most preferably 1 / 20 or more of the molar concentration of carbonate ions and / or bicarbonate ions (when both are contained, the total amount thereof). Also, the molar concentration of the protein is preferably 1 / 1000 or more, more preferably 1 / 500 or more, and most preferably 1 / 200 or more of the molar concentration of carbonate ions and / or bicarbonate ions (when both are contained, the total amount thereof). (pH adjustment) The pH of the solution is preferably in the range of 5 to 10, preferably 5.8 to 8.5. The pH adjustment can be carried out with acids and alkalis that can be used in food production.

[0017] (Powdering) The iron-containing protein composition can be sterilized, concentrated if necessary, and then powdered by spray drying, freeze drying, etc. for use. Sterilization can be carried out according to conventional methods, such as heat sterilization, sterilization, and sterilization treatment by microfiltration (MF). Heat sterilization can be carried out, for example, by low-temperature sterilization at about 65°C for 30 minutes or high-temperature short-time sterilization at about 120°C for 2 to 3 seconds. The concentration treatment is useful when increasing the iron concentration in the final product, and can be carried out by methods such as concentration by membrane treatment using ultrafiltration (UF) membranes, nanofiltration (NF) membranes, reverse osmosis (RO) membranes, etc., and vacuum concentration.

[0018] (Stability) According to the above manufacturing method, an iron-containing protein composition with excellent stability and suppressed precipitation generation can be obtained. "Excellent stability" means that 50 ml of the sample is aliquoted into a 50-ml graduated test tube and centrifuged at 3000 rpm for 15 minutes using a centrifuge MX-301 (manufactured by Tomy Seiko Co., Ltd.), indicating that the volume of the resulting precipitate is 0.5 ml or less. If the formation of precipitate is suppressed to this extent, iron and protein form an iron-containing protein composition, and the characteristic astringent taste and metallic taste of iron are not observed. In addition, the loss of iron-containing protein into the precipitate is effectively suppressed, and it can be said that the quality in the use of the solution for drinking, eating, or as an iron supplement is good.

[0019] (Iron-containing protein composition) The iron-containing protein composition obtained by the above method contains an iron-carbonate-protein complex. The complex is not particularly limited, and specific examples may include an iron-carbonate-casein complex, an iron-carbonate-lactoferrin complex, and an iron-carbonate-bovine serum albumin (BSA) complex. The iron-carbonate-protein complex contained in the iron-containing protein composition may be one kind or a plurality of kinds.

[0020] (Use in food) The iron-containing protein composition can be incorporated into foods such as beverages, fermented milk, and desserts and used as an iron supplement. For example, an iron-fortified beverage containing the iron-containing protein composition can be sterilized by high-temperature short-time sterilization at about 120°C for 2 to 3 seconds and then filled and manufactured.

Example

[0021] Next, the present invention will be specifically described with reference to examples. However, the present invention should not be construed as being limited to the examples.

[0022] (Example 1) 6 kg (89 mM) of sodium hydrogen carbonate and 12 kg (0.7 mM) of WPI were dissolved in 780 kg of prepared water, and the protein (WPI) was completely hydrated at 10 °C overnight. The obtained protein-containing solution (Solution A) was fed into a stirring tank equipped with a homomixer MARKII (manufactured by Primix Corporation), and while the homomixer was stirring at high speed, 2 kg (9 mM) of ferrous sulfate heptahydrate was added and mixed, and held for 10 minutes. Then, it was sterilized at 65 °C for 30 minutes and cooled to 10 °C to obtain 800 kg of an iron-containing protein composition. The pH of the mixed solution was 7.2, and the precipitation amount was 0.1 ml. The color of the aqueous solution immediately after iron addition was light green derived from divalent iron ions, but it turned reddish-brown derived from trivalent iron ions due to stirring. Along with this, a reddish-brown iron-containing protein composition was obtained. As described above, the formation of precipitation was small, and no greenish-white precipitation due to iron(II) hydroxide was observed.

[0023] The molar concentration of the protein-containing solution (Solution A) was adjusted using the average molecular weight. The average molecular weight was calculated from the composition ratio and molecular weight of each protein component in the protein-containing solution calculated from the results of SDS-PAGE.

[0024] (Comparative Example 1) A solution A similar to that in Example 1 was prepared and fed into a mixing tank not equipped with a stirring blade. Then, 2 kg of ferrous sulfate heptahydrate was added to obtain 800 kg of an iron-containing protein composition. The pH of the mixed solution after sterilization and cooling was 7.2, and the precipitation amount was 10 ml. This precipitate was iron(II) hydroxide showing light green (divalent iron ions).

[0025] (Example 2) 6 kg (357 mM) of sodium hydrogen carbonate and 12 kg (2.9 mM) of WPI were dissolved in 180 kg of prepared water, and the protein was completely hydrated at 10°C overnight. The obtained protein-containing solution (Solution B) was fed into a super mixer (manufactured by Yasuda Fine Co., Ltd.). While the super mixer was stirring at high speed, 2 kg (37 mM) of ferric chloride hexahydrate was added, mixed, and held for 10 minutes. Then, it was sterilized at 65°C for 30 minutes and cooled to 10°C to obtain 200 kg of an iron-containing protein composition. The pH of the mixed solution was 7.3, and the precipitation amount was 0.1 ml. After the addition of iron, the color of the aqueous solution became reddish-brown derived from ferric ions, and accordingly, a reddish-brown iron-containing protein composition was obtained. As described above, the formation of precipitation was less, and no greenish-white precipitation due to iron(II) hydroxide was observed.

[0026] (Comparative Example 2) A solution B similar to that in Example 2 was prepared and fed into a mixing tank without a stirring blade. Then, 2 kg of ferric chloride hexahydrate was added and mixed to obtain 200 kg of an iron-containing protein composition. The pH of the mixed solution after sterilization and cooling was 7.3, and the precipitation amount was 12 ml. This precipitate was iron(III) hydroxide showing reddish-brown (ferric ions). It was found that even ferric ions would precipitate without stirring, and an iron-containing protein composition could not be obtained.

[0027] (Example 3) 800 kg of the iron-containing protein composition prepared in Example 1, 2000 kg of raw milk, 1600 kg of skim milk powder, and 15600 kg of water were mixed and dissolved. After plate sterilization at 130°C for 2 seconds, it was cooled to 10°C to prepare 20000 kg of an iron-fortified milk beverage. The iron content of the iron-fortified milk beverage was 2 mg / 100 ml. When the flavor of the iron-fortified milk beverage was evaluated by 10 panelists, the number of panelists who felt an iron taste was 0.

[0028] (Example 4) 200 kg of the iron-containing protein composition adjusted in Example 2 was concentrated using a 5 kDa UF membrane until the retentate reached 100 kg. Then, a part of the concentrated solution was powdered using a spray dryer B-290 (manufactured by BUCHI Corporation). When the flavor of an aqueous solution in which the obtained powder was dissolved to a concentration of 2 mg of iron / 100 ml was evaluated by 10 panelists, the number of panelists who felt an iron taste was 0.

Claims

1. A step of preparing a protein-containing solution containing at least one of carbonate ions and bicarbonate ions and a protein; A step of adding iron to the protein-containing solution while vigorously stirring the protein-containing solution; A step of maintaining the vigorous stirring for 1 minute or more; A method for producing an iron-containing composition, comprising: The method for producing an iron-containing composition, wherein the addition amount of the iron is 100 mM or less.

2. A step of preparing a protein-containing solution containing at least one of carbonate ions and bicarbonate ions and a protein; A step of adding iron to the protein-containing solution while vigorously stirring the protein-containing solution, and a step of maintaining the vigorous stirring for 1 minute or more; A method for producing an iron-containing composition, comprising: The method for producing an iron-containing composition, wherein the molar concentration of the protein is 1 / 1000 or more of the molar concentration of carbonate ions and / or bicarbonate ions.

3. A step of preparing a protein-containing solution containing at least one of carbonate ions and bicarbonate ions and a protein; A step of adding iron to the protein-containing solution while vigorously stirring the protein-containing solution, and a step of maintaining the vigorous stirring for 1 minute or more; A method for producing an iron-containing composition, comprising: The method for producing an iron-containing composition, wherein the protein is whey derived from milk.

4. The method for producing an iron-containing composition according to any one of Claims 1 to 3, wherein the step of adding the iron is a step of adding divalent iron in powder form to the protein-containing solution.

5. The method for producing an iron-containing composition according to any one of Claims 1 to 3, wherein the step of adding iron to the solution is a step of adding an iron-containing aqueous solution in which divalent iron is dispersed in an aqueous solvent to the protein-containing solution.

6. The method for producing an iron-containing composition according to any one of Claims 1 to 5, wherein the pH of the protein-containing solution is 5 to 10.

7. An iron-containing composition produced by the production method according to any one of Claims 1 to 6.