JPH0712276B2 - Decalcified skim milk and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to removed calcium-free skimmed milk and a method for producing the same. The decalcified skim milk of the present invention has excellent properties such as good solubility and high thermal stability of its solution, and thus is widely used as a food material.

Conventional technology Casein, which accounts for 80% of milk protein, exists in milk as micelle particles with an average particle size of 120 nm, and submicelles with a diameter of about 10 nm as a casein-calcium phosphate complex in which calcium phosphate or colloidal potassium phosphate is bound. . Therefore, when calcium is removed from the milk protein, the casein micelles disintegrate into submicelles. It is known that the structure of this submicelle has strong hydrophilicity, and κ-casein is present on the surface of the particles, so that the solubility is remarkably improved.

Conventionally, various techniques for removing calcium from skim milk have been proposed, but in these techniques, the range of change of components other than calcium causes alteration of the calcium-free skim milk due to changes in pH, etc. It has not been widely put into practical use.

In addition, as a method for micelleizing casein in skim milk,
Conventionally, it is generally performed using a reagent such as EDTA, oxalic acid, and citric acid, but in these methods, the reagent components remain in the treated skim milk, which causes problems in using it as a food material. There is.

Further, there is also known a method of increasing the solubility of casein micelles in skim milk by electrodialysis to make them submicelles, but this method does not have the problem of residual reagents such as those mentioned above, but requires a long time for dialysis. Therefore, there is a cost problem industrially.

In recent years, as a method of removing calcium from skim milk, a method of removing calcium simultaneously with phosphate ions by making the skim milk acidic at pH 5.2 to 6.0 and then passing through an anion exchanger has been proposed ( JP-A-60-256342).
That is, this method, by acidifying the skim milk, to release calcium ions from the casein micelles,
This liberated calcium ion is retained on the ion exchanger and removed. However, with this method, the pH
There is a problem that calcium ions cannot be largely removed unless the temperature is near the isoelectric point of casein, and that some of the casein may be curd.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned problems in removing calcium from skim milk, in which skim milk is efficiently removed to remove calcium. It is an object of the present invention to provide a method for producing decalcified skim milk in which the casein micelles of (1) are submicelles and there is no change in composition or pH.

The present invention will be described in detail below.

Structure of the Invention The feature of the present invention is that skim milk is treated with a modified chelating resin in which the chelating groups of the chelating resin are mixed with H-type and Na-type to remove calcium to submicelle casein. The obtained calcium-free skimmed milk has a pH around neutrality almost equal to that of skim milk, has a transparent feeling, does not coagulate by rennet, and has high heat stability.

Further, the skim milk is treated with the modified chelating resin to produce skim milk.

Means for Solving the Problems The present invention will be described based on its production method. As described above, calcium is removed from skim milk using an improved chelate resin in which the chelate type is a mixture of H type and Na type. The skim milk is converted into submicelles.

Generally commercially available chelate resin is Na type, and when the skim milk is treated with this chelate resin, Na ions that have ion-exchanged Ca ions are released and the pH of the skim milk after the treatment shifts to the alkaline side. It is not a good idea to use the chelate resin as it is.

Therefore, in the present invention, a chelate resin obtained by chemically treating a commercially available chelate resin as described below is used so that the pH of the skim milk after the treatment does not change.

That is, the chelate resin is immersed in hydrochloric acid for about 10 to 24 hours to make the chelate group almost H-type, and then further immersed in a sodium hydroxide solution to adjust the pH to around neutral, which is almost equal to that of skim milk. By this operation, a modified chelate resin in which a part of the H-type chelate group becomes Na-type and the chelate group is mixed with H-type and Na-type is obtained.

The modified chelate resin is obtained by immersing the chelate resin in hydrochloric acid so that the chelate group is H type, and by immersing the chelate resin in sodium hydroxide solution to be Na type. It can also be obtained by mixing with stirring. At this time, it is necessary to pay attention to the uniform mixing of the resins.

For fine adjustment of pH or for stable storage, treat the chelate resin modified as described above with NaCl or KC.
Equilibrate in the presence of l to use for treating skim milk.

In order to remove calcium from skim milk using the modified chelate resin obtained as described above, the modified chelate resin obtained by sequentially dipping the chelate resin in hydrochloric acid and a sodium hydroxide solution is used. In this case, skim milk may be passed through a column packed with the resin, or the resin may be dispersed and mixed in the skim milk.

Further, in the modified chelate resin obtained by mixing the H-type chelate resin and the Na-type chelate resin, skim milk may be passed through the column packed as a mixed bed.

The skim milk treated with the modified chelate resin is obtained by centrifuging raw materials (fat ratio of 0.1% or less) (solid content concentration 8 to
9%) or further concentrated to a concentration of 15 to 30%, and when the modified chelate resin is dispersed and mixed in skim milk, the resin should be added in an amount of 20 to 30% by weight based on the skim milk. 30
Process within minutes. When the skim milk is passed through a resin-filled column, the SV (the amount of milk to be passed relative to the amount of resin per hour) is 0.5 to 10.

Calcium is removed by treatment as described above, and skim milk in which casein is a submicelle, when the resin is dispersed and mixed, the resin is removed by centrifugation or filtration, and then sterilized to be in a milk form as it is. Either use it, or concentrate, dry, and pulverize it according to a conventional method and use it.

The recovered resin and the resin in the column are washed with alkali, then washed with deionized water several times to be regenerated, and repeatedly used for calcium removal treatment.

Examples of the results of examining the state of change in the content of each ion of calcium and other metals in skim milk obtained by treating skim milk with the above modified chelating resin as described above by atomic absorption spectrometry Then, it is as shown in Table 1.

As can be seen in Table 1, most of the Ca ions in skim milk are
It can be seen that it is replaced by Na ions and removed.

In addition, the calcium removal process and the pH change state when treated with the Na—H mixed chelate resin according to the present invention are shown in comparison with the case where the treatment is similarly performed using the commercially available Na-type chelate resin. And the attached FIG. 1.

The treatment was a 3% casein micelle solution (ultrafiltration whey).
22 g of each chelate resin was added to 100 ml. Also,
Chelate titration method (metal indicator, dauite N)
N) I went there.

In addition, comparing the Ca removal rate when the skim milk is continuously passed through the modified chelate resin bed by the column method and the Ca removal rate when the modified chelate resin is dispersed and mixed in the skim milk, FIG. As shown in.

As can be seen from FIG. 1, when the modified chelate resin according to the present invention is used for treatment, calcium is removed more efficiently and the pH change is smaller than in the comparative example.

Further, it can be seen from FIG. 2 that the Ca removal rate is determined by the liquid passing rate or the ratio of the resin amount and the treated milk amount.

Effects of the Invention When the skim milk is treated according to the present invention, as described above, pH
The calcium contained in the skim milk obtained by the treatment was able to be removed in a synergistic manner with almost no change in α, and the structure of α- Since the casein and β-casein are present inside and the κ-casein containing sugar is present on the surface, the submicelle is kept stable in an aqueous solution.

Therefore, skim milk consisting of the submicelle casein exhibits the following characteristics.

 Very good solubility.

 Due to its high solubility, highly concentrated solutions can be prepared.

The solution is transparent and odorless compared to skim milk.

 High thermal stability of the solution.

 Does not solidify even after rennet treatment.

Further, the decalcified skim milk obtained according to the present invention, in addition to the above-mentioned characteristics, contains substantially no calcium, and therefore can be used for the following applications.

(B) Protein enhancement of infant milk powder.

(B) Emulsifiers, stabilizers, foaming agents, etc. as food additives.

(C) High-protein pharmaceuticals or nutritional supplements.

(D) Stabilizers and enhancers for meat products.

(E) Stabilizer for heat-labile milk and alcohol-labile milk.

The present invention will be specifically described below with reference to examples.

Example 1 Skim milk having a pH of 6.9 and a solid content of 8.5% was kept at 20 ° C., the modified chelate resin according to the present invention was mixed at a ratio of 12 g / 100 g, and the mixture was sensitized for 30 minutes. After that, suction suction with a paper filter to adjust the pH to 7.0.
A solution of The solid content was 8.5% and no change was observed. The Ca removal rate was 95%. The solution was concentrated to a solid content of 40% using a vacuum concentrator and then spray dried.

The obtained product was a white powder having an average particle size of 60 μm and was excellent in heat resistance and solubility as compared with ordinary skim milk powder.

Example 2 Skim milk having a pH of 6.9 and a solid content of 8.5% was heated to 40 ° C., and passed through a column filled with a modified chelating agent at SV5 and BV (amount of treated milk relative to the amount of resin) of 12, and pH was adjusted to 7. A clear solution of 0 was obtained. The Ca removal rate was 90%. This was concentrated to a solid content of 40% using a plate type vacuum concentrator and then spray dried. The obtained product had an average particle size of 60 μm as in Example 1.
It was a white powder of m and was excellent in heat resistance and solubility as compared with normal skim milk powder.

Next, an example of using the decalcified skim milk powder obtained in the present invention will be shown as Example 3.

Example 3 Using the milk powder obtained in Example 1, a cream powder for coffee addition was manufactured as a trial. 30% hardened palm oil, 20% calcium-free skimmed milk powder, 45% saccharides with phosphates and emulsifiers added,
After dissolved in a solid concentration of 40%, it was spray dried. The cream milk powder thus obtained was superior in solubility to conventional products and was excellent in flavor without casein odor.

[Brief description of drawings]

FIG. 1 shows the state of Ca removal rate and pH change in the case of treating skim milk according to the present invention together with the case of a comparative example, and FIG. 2 shows the treatment of skim milk according to the present invention in a column system. 2 shows the Ca removal rate in the case of continuous operation with and in the case of mixing with the amount of resin.

Claims (4)

[Claims] 1. A skim milk containing chelate resin having a chelate group of H
-Type pH and near-neutral pH, which is almost the same as skim milk, obtained by treating the modified chelate resin with mixed type and Na-type to remove calcium and converting casein into a submicelle.
Decalcified skim milk with high heat stability that does not coagulate even with rennet and has transparency. 2. Skim milk, the chelating group of the chelating resin H
-Type and Na-type mixed chelating resin treated with a modified chelating resin to make casein submicelles, having a pH around neutral that is almost equal to skim milk, transparent, rennet A method of producing decalcified skim milk with high heat stability that does not coagulate due to. 3. A modified chelate resin is a chelate resin soaked in hydrochloric acid to make it H-type, and then soaked in a sodium hydroxide solution so as to be modified so that Na-type and H-type coexist. The manufacturing method according to claim (2). 4. The modified chelate resin is obtained by stirring and mixing H-type chelate resin soaked in hydrochloric acid and Na-type chelate resin soaked in sodium hydroxide solution in deionized water. A method according to claim (2).