JPH04207157A - Production of milk fraction having high alpha-lactoalbumin content and product containing the same fraction - Google Patents

Abstract

PURPOSE:To obtain the title milk fraction having excellent productivity and useful as a substitute for mother milk by subjecting heat-treated milk to cross flow microfiltration membrane treatment, separating a fraction having high alpha-lactoalbumin content onto permeation liquid side and recovering the fraction. CONSTITUTION:Milk such as cow milk heat-treated at >=70 deg.C and cooled at <=69 deg.C is treated with a cross flow microfiltration(MF) membrane using ceramic or high polymer as a raw material and having 0.05-1.0mum pore size in driving conditions of MF membrane device in which differential pressure between membranes is <=0.5MPa and membrane face flow rate is >=0.5m/sec and fraction having high alpha-lactoalbumin content is separated onto permeation liquid side and recovered to provide the objective milk fraction. Furthermore, the milk fraction is subjected to spray drying, etc., to afford powder and the powder is added as milk ingredient to provide substitute for mother milk or nutrition composition for human or animal.

Description

[Detailed description of the invention] Raw! TECHNICAL FIELD The present invention relates to a method for separating and collecting a fraction containing high α-lactalbumin from milk using a cross-flow membrane, and to products containing the fraction.

' and Part 1 In general, whey protein has higher nutritional value and protein utilization efficiency than casein and soybean protein, and is therefore known to be used as a breast milk substitute or as a fluorescent source in human or animal nutritional compositions. There is. Especially when used as a breast milk substitute,
β-lactoglobulin (β-Lg), the main component of whey protein in milk, is a protein that does not exist in breast milk and acts as an allergen for infant allergies.
Reduce Lg or α-lactalbumin (α-
It is said that it is desirable to use a whey protein material with a high La) content.

Therefore, attempts have been made to effectively utilize whey protein by reducing β-Lg or increasing the α-La content from whey produced as a by-product in cheese production and the like.

In other words, many attempts have been made to effectively utilize the differences in the physical and/or chemical properties of proteins using whey as a starting material as a method for separating and recovering fractions with high α-La content. However, these methods have problems such as complicated processes, energy costs, low recovery rates, and irreversible changes in proteins, and it is difficult to scale up to an industrially viable method. Recently, as a fractionation method using a tlF membrane, Peter Harris (Japanese Patent Application Laid-Open No. 57-118758), Maubwa et al.
and Bottomley (Japanese Unexamined Patent Publication No. 1-165343), and these methods also all use whey as a starting material. However, as a result of examining these methods as a practical problem, we found that the pore sizes of industrially used UF membranes vary, and that a-L a (MW 14,000 Da) and β-Lg (
It was difficult to accurately fractionate the MW 36,000 Da dimer). As mentioned above, all conventional methods use whey as a starting material, and α-La using milk as a starting material.
A method for separating and recovering the high-content fraction is not shown.

On the other hand, currently, industrial UF membrane utilization technologies in the dairy industry include whey protein concentrate (WPC), whole milk protein (TM
It is used for concentrating P) and cheese milk, and is essentially only used for separating protein, lactose, and ash. Regarding the technology for using MF membranes, the total filtration method reduces the processing capacity due to membrane clogging, etc., and the membrane's original properties cannot be maintained, so it is used for sludge treatment and other sediment removal. It's just being done. On the other hand, in recent years, a cross-flow single type has been developed that improves the shortcomings of the total filtration type.
It is being considered for use in sterilizing milk, concentrating lactic acid bacteria, removing fat from whey, etc. However, a method for separating and recovering whey protein, particularly a fraction with a high α-La content, using milk as a raw material by MF membrane treatment has not been studied so far.

As described above, the present invention provides good separation and efficient recovery in the process of separating and recovering a fraction with a high α-La content from whey using membrane treatment technology. This was done in an attempt to solve the manufacturing problems associated with conventional α-La separation and recovery, as it was difficult to separate and recover α-La.

The present invention uses a cross-flow MF membrane technology using ceramic and polymer membranes, and heats milk to combine casein and β-
By applying the formation of a complex between Lg, a whey protein fraction with a high α-La content can be obtained on an industrial scale. It is also an object of the present invention to use the obtained fraction with a high content of α-La as a breast milk substitute and a nutritional supplement composition for humans or animals.

That is, the present invention provides milk with a high α-La content, which is obtained by treating heat-treated milk with a cross-flow MF membrane, passing it through the membrane, and separating and recovering a fraction with a high α-La content on the permeate side. This invention relates to a method for producing a milk fraction.

Further, in the present invention, the heat treatment of milk may be performed by heating the membrane during cross-flow MF treatment.

As mentioned above, α-La and β-Lg exist in milk. For example, the molecular weight of α-La in milk is 14,000 Daβ.
- that of Lg is 36000 Da (exists as a dimer). However, with such a difference in molecular weight, it is difficult to separate the two well using a membrane.

β-Lg is a heat-sensitive protein that self-associates with heat or forms a complex with casein in casein micelles (Dairy Sci, Abst, 25.45).
(1963), J. Dairy Sc4.48.11
6H1965)). The present inventors took advantage of this property of β-Lg and the membrane separation technology that has made rapid progress in recent years, and applied it to increase the apparent molecular weight of β-Lg by heating, thereby increasing the molecular weight of α-La. Cross flow midfielder after widening the gap
The membrane treatment successfully separated α-La and β-Lg. As a result, α-La could be obtained in good yield.

The milk used in the present invention includes all types of milk such as cow's milk, mountain milk, annual milk, buffalo milk, etc., regardless of the fat content.

In addition, heat-treated milk includes milk that has undergone a heat history, such as sterilized milk, reconstituted milk (heated compressed milk dissolved in water, etc.), and raw milk (including raw skimmed milk). There are those that are preheated, and also those that involve high temperatures during membrane processing. This heat treatment is desirably carried out at a temperature of 70° C. or higher, at which temperature β-Lg associates and/or polymerizes or forms a complex with casein in casein micelles.

Further, cross-flow MF membrane processing is a technology that has rapidly developed recently. Cross-flow filtration is a method in which, unlike the conventional total filtration method, the feed liquid is flowed along the membrane surface so as to cross perpendicularly to the direction in which the permeate is flowing. Characteristically, processing capacity and membrane fractionation properties can be maintained well. Furthermore, the MF membrane is a separation membrane whose pore diameter is accurately measured by separating particles. Its pore diameter is 0.01μm
~ up to several micrometers, and is made of ceramic or polymer material. In the present invention, the pore size is 0.05 to 1,0
It is preferable to use a μ-free membrane. If the pore size is less than 0.05 μm, it is difficult for both α-La and β-Lg to pass through the membrane, making it impossible to adequately fractionate both α-La and β-Lg.

Further, when the pore size is 1.0 μm or more, β-Lg whose apparent molecular weight has increased due to heating passes through the membrane together with α-La, and a portion of the casein micelles also permeate, making it impossible to fractionate α-La. The operating conditions of the cross-flow MF membrane device are a pore-membrane differential pressure of 0.5 MPa or less, and a membrane surface flow rate of 0.5 MPa or less.
When operating at a speed of 5 m/sec or more, α-La and β-
can be separated from Lg.

To explain the method of the present invention using Table 1, when using non-heat-treated milk such as skim milk or whole-fat milk as a raw material, the heat treatment is performed at 70°C as described above.
It is preferable to heat it above, cool it, and process it with a cross-flow MF membrane at room temperature. When not heat-treated, it is recommended to perform cross-flow high-temperature MP membrane treatment to simultaneously form casein complexes with β-Lg and membrane treatment. When using raw milk, it is recommended to treat it with MP membrane treatment at room temperature.

In this way, α-La can pass through the membrane and α-La with a high α-La content can be obtained. This permeate usually contains about 0.1% of α-La, lactose, ash, and the like.

Table 1 Concentrated liquid Permeated liquid α-La remains in . In the present invention, this concentrated solution is diluted by adding a solution that does not contain α-La, such as water, and then subjected to DF (diafiltration) lI! It is also possible to perform the treatment to allow the remaining α-La to permeate, and to combine this permeate with the MF membrane treated permeate.

The permeate thus obtained contains α-
In addition to La, it contains lactose, ash, water, etc. Therefore, in the present invention, only α-La may be fractionated and concentrated from this permeate by using an LJF membrane through which α-La does not permeate. The UF membrane used here has a molecular weight of α-La of 14,000.
Da, so a membrane with a molecular weight cut-off of substantially 140,000 a or less is used.

The concentrate obtained in this way can be used as it is or by drying methods such as spray drying or freeze drying to form a powder and be added to powdered milk for infants as a substitute for breast milk, or as a nutritional composition for humans or animals. Can be used.

211 and Achievements According to the method of the present invention, a milk fraction with a high α-lactalbumin content can be separated and recovered from milk with a high yield using a cross-flow MF membrane.

The dry powder of this fraction and products obtained by adding it to powdered milk for infants, etc., have high nutritional value and protein utilization efficiency.

Next, the present invention will be specifically described with reference to Examples.

Example 1 As the milk, skim milk powder manufactured by Snow Brand Milk Industry ■ was used.

This skim milk powder has at least 75%
It was heat treated at ℃ for 15 minutes.

This skimmed milk powder was reconstituted with deionized water.

The analytical values (weight %) of the reduced skim milk were as follows.

Total solids 7.5 Protein (Nx6.38) 3.1a-La/β
-Lg O,34 Fat 0.05 Carbohydrate 3.68 Ash 0.67 pH 6.5 20 kg of reduced skim milk was treated with a ceramic membrane (α-alumina) monolith type 9 manufactured by NGK with a membrane area of 0.33rd.
Cross flow MF using 48F, pore size 0.1 μm
Membrane filtration was performed. The operating conditions were a temperature of 12' C1, an average operating pressure of 0.1 MPa, and a membrane surface flow rate of 1.6 m/sec.

Concentration was carried out to a concentration factor of 2, and 10 kg of a concentrated liquid and 10 kg of a permeated liquid were obtained. The permeate contains 12.0% of initial skimmed milk.
9% α-La and 1.8% β-Lg were transferred.

Due to the membrane treatment, the ratio of α-La/β-Lg was 0.34 in skim milk, but in the permeate, α-La showed a high value of 2.43.

Further, 10 kg of this concentrate was subjected to DF membrane treatment while maintaining the amount of concentrated milk at 10 kg and adding deionized water to the concentrated milk. In other words, diafiltration (DF) was performed. The treatment was terminated when an amount of permeate (=amount of water added) of 10 kg was obtained. At this time, in 10 kg of permeate,
22.8% α-La and 2.9% β-Lg in concentrated milk
The ratio of α-La/β-Lg in the permeate through diafiltration is 2.51, which is also α-
La showed a high value. In the end, 32.8% a-La and 4.6% β-Lg migrated to the permeate side in 2x concentration and 1x diafiltration, compared to the high migration rate of α-lactalbumin. , that of β-lactoglobulin was low.

Example 2 Raw skimmed milk consisting of the following components (% by weight) was used.

Total solids 8.81 Protein (NX6.38) 3.31α-La/
β-Lg O, 33 Fat 0.12 Carbohydrate 4.64 Ash 0.74 100 kg of raw skimmed milk at pH 6 was heated at 85°C for 110 minutes in a Fordra tank, and heated to 100 kg of raw skimmed milk with a membrane area of 0.42 rd manufactured by Millipore. Cross-flow MF membrane filtration was performed using a ceramic membrane Ceraflow with a pore size of 0.2 μm. The operating conditions were: temperature 50°C, average operating pressure 0.1 MPa, and membrane surface flow rate 2.0 m.
/sec. Concentration and diafiltration were performed as in Example 1.

The transfer rates of α-La and β-Lg to the filtrate obtained by 5-fold concentration were 37.2% and 5.2%, respectively, and α-La/β-
The ratio of Lg was 0.33 in the skim milk, but it was 2.56 in the permeate, and a permeate with a high α-La content was obtained.

In addition, the transfer rate to the permeate obtained by diafiltration was 34.2% for α-L a and 4.4% for β-Lg, respectively.
% aL, the ratio of a/β-Lg is 2.80, α
-A fraction with high La content was obtained. After all, 5 times concentrated, 1
α-La approx. 58.6% in double diafiltration region
About 9.8% of β-Lg was transferred to the permeate side, and as in Example 1, the transfer rate of α-La was higher than that of β-Lg.

Example 3 α-La enriched permeate obtained in Examples 1 and 2 150
Protein concentration and purification were performed using 1 kg. The components of the permeate used are shown below (% by weight).

Total solid content 4.18 Protein (NX6.38) 0.39 (Pure protein 0.12) Fat O Carbohydrate 3.47 Ash content 0.32 pH6.5 Manufactured by DOW (7) UF membrane GR81PP, molecular weight cut off 60
00Da, 0.36rrr, DOW's UP device La
b-20 and concentrated 50 times to obtain 3 kg of concentrated liquid.

The components of the concentrate (wt%) are: Total solids 20.90 Protein (NX6.38) 8.94. (Pure protein 6.00) Fat 0 Carbohydrate 10.38 Ash 1.58 pH 6.2. In addition, α-La by 5O3-PAGE analysis
The and β-Lg concentrations were 3.38% and 1.24%, respectively, and the α-L a /β-Lg ratio was 2.7, the same as the value before treatment.

Equal volume diafiltration was performed to further increase protein concentration. For this purpose, 9 kg of deionized water, which corresponds to three times the amount of concentrate, was added. 3 kg obtained
The components (wt%) of the concentrate are: total solids 8
．． 89 Protein (NX6.38) 6.89 (Pure protein 6.00) Fat O Carbohydrate 1.3 Ash 0.80 pH 6.8, and the protein in the total solid was 77.5%.

According to 5O3-PAGE, the α-La and β-Lg concentrations in this concentrated solution were 3.36% and 1.20%, respectively, and the ratio of α~La/β-Lg was the same as the value before treatment. It was.

Example 4 Concentration f1. described in Example 3. (total solids 20.90%, protein 8.94%, fat 0%, carbohydrates 10.38%, ash 1.58%) was desalted by a conventional method, and the desalted concentrate (total solids 18. 12%, protein 8.05%, fat 0%,
Carbohydrate 9.90%, natural content 0.17%) 100.6 kg,
After dissolving 6.4 kg of casein, milk [32.6 kg, 2 kg of vitamins and minerals, add 27.6 kg of vegetable oil to this.
g was mixed and homogenized. The resulting solution was sterilized, concentrated and dried in a conventional manner to obtain 100 kg of powdered milk substitute for breast milk.

Example 5 19.3 kg of skim milk powder, 1.32.1 kg of milk, and 1.32 kg of hitamint mineral component were dissolved in 116.7 kg of the desalted concentrate described in Example 4, and then 27 kg of vegetable oil was dissolved in this.
．． 7 kg were mixed and homogenized. The resulting solution was sterilized, concentrated and dried in a conventional manner to obtain 100 kg of powdered milk substitute for breast milk.

Example 6 After 28.5 kg of dextrin and 1.6 kg of vitamin and mineral components were dissolved in 288 kg of the desalted concentrate described in Example 4, 16.4 kg of vegetable oil was mixed therein and homogenized. The obtained solution was sterilized, concentrated and dried by a conventional method to obtain 100 kg of powdered nutritional food.

Claims (9)

[Claims] (1) The heat-treated milk or the milk at the same time as the heat treatment is treated with a cross-flow microfiltration (MF) membrane, and a fraction with a high α-lactalbumin content is separated and collected from the permeate side. Method for producing a milk fraction with high α-lactalbumin content (2) α according to claim (1), wherein the heat-treated milk is one or more types of milk selected from the group consisting of sterilized milk, reconstituted milk, heated concentrated milk, and preheated raw milk.
-Production method of milk fraction with high lactalbumin content (3) The milk fraction having a high α-lactalbumin content according to claim (1) or (2), wherein the milk heat-treated to 70°C or higher and cooled to 69°C or lower is treated with a normal temperature cross-flow MF membrane. Manufacturing method (4) The milk with a high α-lactalbumin content according to claim (1) or (2), wherein a heat-resistant membrane is used as the cross-flow MF membrane, and the milk is subjected to the cross-flow MF membrane treatment at a temperature of 70°C or higher. Method for producing fractions (5) The cross-flow MF membrane is made of ceramic or polymer and has a pore size of 0.05 to 1.0 μm, and the operating conditions for the cross-flow MF membrane device are that the transmembrane pressure is 0.5 MPa or less. , according to any one of claims (1) to (4), wherein the membrane surface flow velocity is 0.5 m/sec or more.
-Production method of milk fraction with high lactalbumin content (6) The heat-treated milk or the milk at the same time as the heat treatment is treated with a cross-flow MF membrane, and the concentrated liquid is further treated with a diafiltration (DF) membrane, and the permeate is converted into a cross-flow MF membrane permeate. In addition, a method for producing a milk fraction with a high α-lactalbumin content, which is characterized by efficiently recovering a fraction with a high α-lactalbumin content. (7) DF membrane permeate and crossflow MF of claim (6)
A method for producing a milk fraction with a high α-lactalbumin content, which comprises treating the combined liquid with the membrane permeate through a UF membrane and recovering a concentrated liquid. (8) Milk fraction powder with high α-lactalbumin content obtained by spray-drying or freeze-drying the fraction obtained according to any one of claims (1) to (7). (9) A breast milk substitute or a nutritional composition for humans or animals containing the fraction obtained according to any one of claims (1) to (8).