JPS5948964B2 - Method of manufacturing infant milk similar to human milk - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing infant milk similar to human milk.

Conventionally, various improvements have been made to the composition of milk for infants, such as proteins, carbohydrates, fats, minerals, vitamins, etc., in order to bring the composition of infant milk closer to that of human milk.

Among these, reinforcement of whey protein has been mainly adopted as a means of improving protein composition.

However, this merely brings the blending ratio of whey protein and casein in milk closer to that of human milk, and does not improve the qualitative protein content.

The object of the present invention is to provide a method for producing infant milk in which the qualitative content of protein, particularly casein, is improved, that is, the composition of casein is brought closer to that of human milk. is protein concentration 0.5-6%, pH 7-1
Add a casein alkali metal salt solution adjusted to 0 to 15
After cooling to ℃, divalent cations were added to the solution, and the resulting precipitate was removed.
This is a method for producing infant milk similar to human milk, which is characterized in that it is used as a protein casein component in the production of infant milk consisting of carbohydrates, fats, minerals, vitamins, etc.

The present invention will be explained in detail below.

Milk casein is not a single protein, but mainly αS
It consists of -9β-5 and one casein.

On the other hand, human milk casein does not contain αS-casein and mainly contains components similar to the β- and di-casein of cow's milk casein.

Therefore, if αS-casein is removed from cow's milk casein or casein with reduced α8-casein content is obtained and used in the production of infant milk, it is possible to produce infant milk with a protein composition closer to that of human milk than conventional milk casein. You will be able to get milk.

Many researchers have previously reported methods for separating casein into its components.

For example, a method that utilizes the difference in solubility of each component of casein in a urea solution, a method that separately precipitates each component of casein from an alcohol solution by changing temperature, pH, and ionic strength,
There is a method of fractionating a casein urea solution by gel filtration using Sephadex, and there are many other methods.

However, these methods require complicated operations, are difficult to implement on an industrial scale because they target the throughput at the laboratory level, and do not take economic efficiency such as yield into account. there were.

The present inventors succeeded in separating each component of casein on an industrial scale using relatively simple operations and at low cost to obtain casein suitable for producing milk for infants that is similar to human milk.

Specifically, a casein alkali metal salt solution adjusted to a protein concentration of 0.5 to 6% and a pH of 7 to 10 is cooled to 0 to 15°C, and then divalent cations are added thereto to obtain β- and di-casein. It is possible to selectively precipitate only αS-casein without precipitating it, and when casein is separated from the liquid from which this precipitate is removed, human milk with a low content of αS-casein and mostly composed of β- and casein is obtained. It has been found that casein suitable for the production of infant milk similar to the above can be obtained.

The present invention was completed based on this knowledge.

The alkali metal salt solution of casein used in the present invention is prepared by dispersing acid casein obtained from raw milk, skim milk, or reduced skim milk by isoelectric focusing method in water, and then dispersing it in water. Sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, etc.) and dissolved at pH 7 to 10 and adjusted to a protein concentration of 0.5 to 6%, or commercially available sodium caseinate or potassium caseinate. Any product that is dissolved in water, dissolved at pH 7 to 10 by adding an alkali metal salt, and adjusted to a protein concentration of 0.5 to 6% can be used.

Appropriate protein concentration is 0.5-6%, 1-3%
is optimal.

Table 1 shows actual and experimental results regarding the influence of protein concentration on the precipitation of casein components.

The temperature of the casein solution in this experiment was 2℃6, p
H was 7, and centrifugation of the precipitate was performed at 8000 r, p, m.
, for 10 minutes.

Note that calcium chloride was used as the divalent cation to be added.

Differential determination of each casein was performed using disk electrophoresis.
After electrophoresis, the gel was stained with amide black, the corresponding band was cut out from the gel, and colorimetric analysis was performed using the dye extraction method.

The fractional quantification of each casein in Tables 2 to 6 below was also carried out in the same manner as above.

Note that the recovery rate to the supernatant in Table 1 is the same in Table 3.

From the results in Table 1, it can be seen that when the protein concentration exceeds 7%, casein gels, the amount of supernatant becomes extremely small, and each component is not sufficiently separated, and 6% is the upper limit.

Also, lower protein concentrations are better in terms of separation, but
If it is too low, the liquid volume will be too large and it is not practical, 0.5%
The above is appropriate.

Regarding the pH, if the pH is 7 or more and 10 or less, there is almost no difference in the precipitation of αS-casein and the persistence of β- and Ni-casein in the supernatant.

The experimental results regarding the influence of pH on the precipitation of casein components are shown in the drawings and Table 2.

The figure shows a protein concentration of 0.5%, a temperature of 2℃, and a pH of 5 to 10.
Calcium chloride concentration (mM) is plotted on the horizontal axis for the five stages, and the precipitation rate (%) for each.

The protein (casein) was quantified by measuring ultraviolet absorption at 280 nm.

Further, Table 2 shows the analytical values at pH 7 and pH 10 at a protein concentration of 0.5%, a temperature of 2° C., 0, and a calcium chloride concentration of 75 mM.

In this case, the precipitate was centrifuged at 800 r, p, m.
, for 10 minutes.

The graphs are very close to each other when the pH ranges from 7 to 10, and there is almost no difference in the precipitation rate, but it can be seen that the precipitation rate is high when the calcium chloride concentration is 50 to 100mM.

Table 2 also shows that at pH 7 and 10, the recovery rate to the supernatant (
It can be seen that there is almost no difference in the residual rate).

At pH 11 or higher, αS-casein hardly precipitates, making it unsuitable for separation.

In practice, pH 7 is optimal.

The temperature is preferably kept at 0 to 15°C.

Table 3 shows the experimental results regarding the influence of temperature on the precipitation of casein components.

This experiment was carried out at different temperatures at a protein concentration of 0.5%, pH 7, and calcium chloride concentration of 75 mM, and the precipitate was centrifuged at 8000 rpm for 10 minutes.

From the results in Table 3, the recovery rate of casein in the supernatant and its purity (low content of αS-casein and high content of β- and 2-casein are considered to have excellent purity). Considering this, it is recognized that cooling to 15° C. or lower is preferable.

In other words, casein components can be separated even at 20°C, but
This is not preferred because the recovery rate of casein to the supernatant is quite low.

The recovery rate of casein to the supernatant is the best in the case of cooling at 0 to 5°C, but the residual rate of αS-casein in the supernatant is slightly higher than in the case of 15°C.

However, the purity of αS-casein obtained as a precipitate is highest in this temperature range.

On the other hand, in the case of 15°C, the content of αS-casein in casein remaining in the supernatant is the lowest.

In view of the above, in the case of the present invention which requires a mixture of β- and di-casein, it is preferable to maintain the temperature at 0 to 15°C.

In the present invention, the divalent cations added to the alkali metal salt solution of casein include calcium, magnesium,
Barium, strontium, manganese, cobalt, nickel, and copper are suitable; for example, CaC1°, Ca(CH3C
OO)25MgC129MgSO4゜BaCl2,5r
C1゜5MnC12, CoC1゜, CuSO4, NiC
It is used in forms such as 1°.

Calcium is optimal from a food hygiene perspective.

The optimal concentration of divalent cations differs depending on the type of cation.

The experimental results for calcium are shown in Tables 4 and 5, and the experimental results for other divalent cations are shown in Table 6.

Table 4 shows protein concentration of 0.57%, pH of 7, and temperature of 2°C.

So, Table 5 shows that the protein concentration is 5.3%, the pH is 7, the temperature is 2°C,
Table 6 shows the results of experiments conducted at different concentrations of CaCl2, with protein concentration of 0.54%,
CaCl21MgC12°BaC at pH 7 and temperature 2°C
1□ and 5rC1□ at different concentrations.

In both cases, the precipitate was centrifuged at 8000 r, p,
m for 10 minutes.

In the case of calcium, considering the purity of casein remaining in the supernatant in Tables 4 and 5, 50-100mM is appropriate, and when the protein concentration is high, 75-100mM is recommended from the results in Table 5. It turns out that this is preferable.

In addition, based on the purity of casein remaining in the supernatant in Table 6, magnesium is 25-50mM, and barium is 100-150mM, although the recovery rate of casein in the supernatant is low.
It can be seen that 25 to 75mM is appropriate for strontium.

Another condition may be the influence of the ionic strength of coexisting salts other than divalent cations, but regarding this, I-0,
If it is 2 or less, there is no effect on the degree of separation.

Regarding the timing of adding divalent cations and the precipitate formation time, it is sufficient to add the divalent cations when the alkali metal salt solution of casein reaches a predetermined temperature, and no time is required for precipitate formation.

In fact, immediately after adding divalent cations, the amount of αS-casein remaining in the solution after removing the precipitate by centrifugation or the like is smaller, and better results in terms of purity can be obtained.

Note that when an equal amount of ethanol is added to the solution containing casein with a low αS-casein content obtained as described above, αS-casein further precipitates.
The αS-casein content can be further reduced.

In the present invention, casein is separated from the liquid containing casein mainly composed of β- and mono-casein with a low content of αS-casein obtained as described above, and used as casein in the production of infant milk.

This separation of casein can be carried out, for example, by using the α
A solution containing casein mainly composed of β- and mono-casein with a low content of S-casein is subjected to isoelectric precipitation by adding an acid, precipitation by adding an organic solvent, salting out by adding a neutral salt, or This can be carried out by treatment such as ultrafiltration.

In the present invention, the objective is achieved according to a conventional method for producing infant milk, except that the casein mainly composed of β- and di-casein with a low content of αS-casein obtained as described above is used as the casein component of the protein. It is possible to produce milk for infants.

That is, casein obtained as described above and whey protein [e.g. milk whey (cheese whey, acid whey, etc.)]
, ultrafiltered milk whey, or a solution of separately isolated milk whey protein can be used] to which appropriate carbohydrates, fats, minerals, vitamins, etc. are added and mixed to produce infant milk. .

The milk for infants obtained according to the present invention has a protein composition closer to that of human milk than conventional milk, and is an excellent milk for infants that provides good nutritional and physiological results for infants.

Next, examples of the present invention will be shown.

Example 1 IN hydrochloric acid is added to skim milk to adjust the pH to 4.6 to precipitate casein.

The casein precipitate is collected by centrifugation, and the precipitate is dispersed in 3 times the volume of water.

IN sodium hydroxide solution is added to this to dissolve the casein and the final pH is adjusted to 7.

The protein concentration of this solution is approximately 5%.

This is cooled to 2° C., and 1/40th of the liquid volume of a cooled 3M calcium chloride solution is added while stirring (calcium chloride concentration is 75 mM).

Since a precipitate will form immediately, centrifuge at 800 rpm while keeping it cool.

for 10 minutes to separate the supernatant and precipitate.

After dispersing the precipitated fraction in water, the pH is adjusted to 4.6 with IN hydrochloric acid, stirring is continued, and the precipitate is collected to obtain acid-precipitated αS-casein.

The supernatant fraction is adjusted to pH 4.6 by adding IN hydrochloric acid, and the precipitate is collected to obtain a casein mixture as acid casein with a low content of αS-casein and consisting mainly of β- and mono-casein.

The purity of casein in the fraction thus obtained is as follows.

The acid casein obtained from the above supernatant fraction is washed with water, compressed, ground, and then dried with ventilation.

30 parts of water is added to 1 part of this dry casein powder and 1.97 parts of edible lactose, and the mixture is uniformly dispersed to form a suspension.

0.05 part of sodium hydrogen carbonate is added to this, heated, and stirred while maintaining the liquid temperature at 50 to 60°C to dissolve casein and lactose.

Add 3.19 parts of vegetable oil containing fat-soluble vitamins and 8.43 parts of desalinated whey powder (demineralization rate 63%) to this solution, and stir while maintaining the liquid temperature at 50-60°C until uniform. Disperse and dissolve.

Some impurities are removed by filtration, and then heat sterilized (98%
After emulsifying with a homogenizer (at ~105°C for 2 seconds), the mixture is concentrated with an evaporator to a solid concentration of 40%, and spray-dried.

Vitamins, minerals and other micronutrients were added and mixed to the powder thus obtained to obtain powdered milk products for infants.

Example 2 Commercially available sodium caseinate is dissolved in water to a protein concentration of 0.5%.

Pour this with IN sodium hydroxide solution or IN hydrochloric acid.
After adjusting H to 7, cool to 15°C.

Add 1/40th of the liquid volume of 3M calcium chloride solution while stirring (calcium chloride concentration is 75mM).
.

Since a precipitate forms immediately, the supernatant and precipitate are separated by centrifugation at 800 Or, p, m for 10 minutes while maintaining the temperature at 15°C.

The supernatant and precipitate are collected in the same manner as in Example 1 in the form of acid casein.

The purity of both casein obtained is as follows.

The casein obtained from the above supernatant fraction is washed with water, compressed, ground, and then dried with ventilation.

30 parts of water is added to 1 part of this dry casein powder and 5.94 parts of edible lactose, and the mixture is uniformly dispersed to form a suspension.

Add 0.05 part of sodium hydrogen carbonate to the mixture and heat, stirring while maintaining the liquid temperature at 50 to 60°C to dissolve casein and lactose.

2.9 parts of vegetable oil with fat-soluble vitamins added to this solution and Ultra Oki membrane-treated whey powder (whey was concentrated and dried to 1.8 times the solid content using an Ultra 6-layer membrane) 3
．． Add 73 parts and stir to uniformly disperse and dissolve while maintaining the liquid temperature at 50 to 60°C.

Some impurities are filtered and removed, and then heat sterilized (98%
-105°C for 2 seconds), vitamins, minerals and other micronutrients were added and mixed, and further emulsified with a homogenizer to obtain milk for infants.

Example 3 Casein was fractionated in the same manner as described in Example 1 except that the protein concentration of the solution was changed from 5% to 0.5%.

The purity of casein in the obtained fraction is as follows.

Acid casein obtained from the supernatant fraction is washed with water, compressed, and ground.
Dry with ventilation.

Same as described in Example 1 except that the dry casein powder and the mixture of vegetable oil and milk fat (vegetable oil: milk fat - 18 nia) obtained as described above were used instead of the dry casein powder and vegetable oil in Example 1. and obtained milk for infants.

[Brief explanation of drawings]

The drawing shows the influence of pH on the precipitation of casein components.

Claims (1)

[Claims] 1 After cooling a casein alkali metal salt solution adjusted to a protein concentration of 0.5 to 6% and a pH of 7 to 10 to 0 to 15°C, divalent cations were added thereto, and the resulting precipitate was removed. Separated casein is separated into proteins, carbohydrates, fats,
A method for producing infant milk similar to human milk, characterized in that it is used as a casein component of protein in the production of infant milk containing minerals, vitamins, etc.