WO1995019714A1

WO1995019714A1 - Process for fractionating whey proteins and the components so obtained

Info

Publication number: WO1995019714A1
Application number: PCT/FI1995/000027
Authority: WO
Inventors: Marko Outinen; Matti Harju; Olli Tossavainen; Pirkko Antila
Original assignee: Valio Oy
Priority date: 1994-01-21
Filing date: 1995-01-20
Publication date: 1995-07-27
Also published as: EP0757522A1; FI96090B; AU1419395A; FI940316A; FI96090C; FI940316A0

Abstract

The invention relates to a process for fractionating whey or whey protein solution into an alpha-lactalbumin component and a beta-lactoglobulin component, and to an alpha-lactalbumin component and a beta-lactoglobulin component so obtained. The process of the invention comprises (a) clarifying a batch of whey or whey protein solution and (b) passing whey or whey protein solution treated at stage (a) through a chromatography column packed with a strong polystyrenebased anion exchange resin, and recovering the fraction leaving the column; (c) washing the anion exchange resin column treated at stage (b) with deionized water, the obtained solution being recovered as an alpha-lactalbumin component; which is followed by (d) eluting the washed anion exchange resin column with a weak aqueous NaCl solution and recovering the eluate as a beta-lactoglobulin component.

Description

Process for fractionating whey proteins and the components so obtained.

The invention relates to a process for fractionating whey proteins. More specifically, the invention relates to a process for fractionating whey or whey protein solution chromatographically select¬ ively into an alpha-lactalbumin component and a beta- lactoglobulin component, and to an alpha-lactalbumin component and beta-lactoglobulin component so obtained. The obtained alpha-lactalbumin component is as such suitable for use in infant food formulas, and the obtained beta-lactoglobulin component in turn is as such suitable for use as a protein component in clinical nutritive preparations and various products of the food industry.

Milk whey proteins are used inter alia in infant food formulas on account of their high digestibility and excellent nutritional value. In general the pro¬ tein of infant food formulas is composed of milk casein and whey protein in a ratio of 40:60 (casein: whey protein) , which corresponds to the ratio between casein and whey protein in human milk. However, the protein composition of infant food formulas does not fully correspond to that of human milk, as the whey protein of cow's milk differs in composition from the whey protein of human milk; human milk contains no beta-lactoglobulin (β-LG), which is the main component of the whey protein of cow's milk. On the contrary, the whey protein of cow's milk, alpha-lactalbumin (α- LA), is nearly identical with the α-LA of human milk. As the protein of human milk is mainly composed of - LA (approx. 40% by weight), it would be nutritionally advantageous to use an alpha-lactalbumin fraction separated from cow's milk with the highest possible purity as the main protein component in infant food formulas.

As certain functional properties of β-LG (such as solubility within a wide pH range and good gelific- ation ability) are clearly better than those of whey protein concentrate (WPC), β-LG is regarded as well suited for use in the food industry. At present, the food industry uses WPC but is waiting for the entry into market of an economically feasible beta-lacto¬ globulin [D.M. Mulvihill, Food Research Quarterly 51 (1991) 65-73]. WPC is used e.g. in clinical nutritive preparations. In yoghurts, fresh cheeses and curd, it is used to replace casein. In curd, as much as 20% by weight of the casein can be replaced with whey pro¬ tein. Beverage industries use fatless WPC to increase the protein content of various sports drinks and soft drinks. WPC is also added to flavoured milk drinks (such as cocoa) to increase viscosity and colloidal stability. In the production of sausages, as much as 20% by weight of the protein of meat can be replaced with whey protein. WPC has also been used in the production of ice-cream, ice-lollies, meringue (only fatless WPC) and chocolate coatings [D. M. Mulvihill, Food Research Quarterly 51 (1991), 65-73].

In J. Dairy Res . , 52 (1985) 167-181, P. J. Skudder describes a process where α-LA and β-LG con¬ taining fractions can be separated from cheese or casein whey by strong anion exchange resin (Spherosil QMA, Sepracor, France). Spherosil QMA resin is composed of silica particles (diameter between 100 and 300 μm) coated with styrene vinyl triethoxysilane co- polymer to which quaternary ammonium groups are attached. This resin has a mean pore size of 1,250 A, a pore volume of 1 cm³/g and a specific surface area of 25 m²/g. This known process is based on the fact that β-LG has a higher affinity for this particular resin than other whey proteins. Accordingly, when whey is passed through a resin column regenerated into chloride form, the fraction obtained first contains only small amounts of β-LG. As the capacity of the column becomes full, β-LG also begins to leave the column. Thus a fraction containing great amounts of α- LA (alpha-fraction) is obtained by cutting off the eluate passed through the column at a suitable point. Whey protein attached to the column (beta-fraction containing mainly β-LG) can be released from the resin with a weak hydrochloric acid solution (usually 0.1 N HC1). However, Spherosil QMA resin used in the process is disadvantageous in that its particle size is small for industrial applications and it is very expensive. In U.S. Patent 5,077,067, Thibault describes a process where whey protein is fractionated e.g. by the inexpensive Duolite A101 anion exchange resin by cir¬ culating a suitable amount of whey through an ion exchange column, whereby β-LG is bound to the resin and the obtained solution is substantially free of β- LG. This is how this known process should operate in theory. However, despite a great number of experi¬ ments, it has not been proved that Duolite A101 oper¬ ates in the alleged way; contrary to what has been reported, this resin binds no β-LG. This appears from Example 8 set forth below. In addition, the Thibault process allows native whey (ash content less than 1% by weight) to be treated only within a pH range be¬ tween 4 and 6. Whey with a high salt content (ash content between 1 and 3% by weight) can be treated within a pH range between 6 and 8.

The object of this invention is to provide an industrially applicable process which avoids the above-mentioned drawbacks and which allows whey or whey protein solution to be fractionated selectively into an alpha-lactalbumin component and a beta-lacto¬ globulin component.

The invention relates to a process for frac¬ tionating whey or whey protein solution chromato- graphically selectively into an alpha-lactalbumin component and a beta-lactoglobulin component. The process is characterized by a) clarifying a batch of whey or whey protein solution and, if required, removing glycomacropeptides from it; b) passing whey or whey protein solution treated at stage a) through a chromatography column packed with a strong polystyrene-based anion exchange resin, which resin has a great pore size ranging between 1,000 and 2,000 A and a pore volume of at least 0.9 cm³/g and in which quaternary alkyl amine or alkyl alkanoamine groups, preferably alkyl alkanoamine groups, are attached to a styrene-divinyl-benzene- polymer matrix, and which has a particle diameter between 300 and 600 μm, and recovering the fraction leaving the column; c) washing the anion exchange resin column treated at stage b) with deionized water, the wash water being combined with the fraction recovered at stage b), and the obtained solution being recovered as an alpha-lactalbumin component; which is followed by d) eluting the washed anion exchange resin column with a weak aqueous NaCl solution and recover¬ ing the eluate as a beta-lactoglobulin component. The process according to the invention is suitable for fractionating proteins from different types of wheys and whey protein solutions, such as cheese and casein whey, demineralized whey and whey protein concentrate. It is particularly well suited for fractionating casein whey into an alpha-lact- albumin component and a beta-lactoglobulin component.

It has now been unexpectedly found that whey or whey protein solution can be fractionated more effect¬ ively than previously by the strong anion exchange resins Diaion HPA 25 and HPA 75 (Resindion, Mitsubishi Kasei Corp., Japan), which are much cheaper than the Spherosil QMA resins. Quaternary alkyl amine (HPA 25) or alkyl alkanoamine (HPA 75) groups are attached to the styrene-divinyl-benzene-poly er matrix of these HPA resins. Due to their great pore size (1,000 to 2,000 A), pore volume (0.9 cm³/g) and specific surface area (23 to 25 m²/g), these HPA resins are suitable for separating large molecules. The price of the HPA resins is only about 1/100 of that of the Spherosil QMA resins. HPA resins are well suited for industrial applications on account of their appropriate particle size (diameter 300 too 600 μm) and mechanical strength. A further advantage of the HPA resins is that protein attached to them can be eluted by a 2 to 5 wt.% NaCl solution, whereas less safe hydrochloric acid has to be used to elute protein attached to Spherosil QMA resin in the process described by P.J. Skudder in J. Dairy Res . , 52 (1985), 167-181. The NaCl treatment is also to be preferred over HC1 from the viewpoint of preserving the nativity of the protein.

Moreover, the process according to the invention allows most of β-LG to be separated from native whey (ash content less than 1% by weight) into a fraction substantially free of other whey proteins within a pH range between 6 and 7 without pH adjustment, whereas native whey can be treated in the process described in US Patent 5,077,067 only within a pH range between 4 and 6.

The attached drawings give chromatograms obtained by Fast Protein Liquid Chromatography, FPLC, for the alpha-lactalbumin and beta-lactoglobulin fractions of whey.

Figure 1 shows FPLC chromatograms obtained for the alpha-lactalbumin and beta-lactoglobulin fractions of casein whey with HPA 75 resin according to the in¬ vention;

Figure 2 shows FPLC chromatograms obtained for the alpha-lactalbumin and beta-lactoglobulin fractions of casein whey with Spherosil QMA LS resin. At process stage a), whey or whey protein solu¬ tion is clarified by precipitating residual casein, phospholipoprotein and calcium phosphate by an in¬ crease in pH, an addition of CaCl₂'2H₂0 and a light heat treatment, and by removing the precipitate by decantation, centrifugation or microfiltration. The clarification method does not significantly affect the protein composition of wheys.

At process stage b), whey or whey protein solu¬ tion treated at process stage a) is passed through a chromatography column packed with a strong poly¬ styrene-based anion exchange resin, which resin has a great pore size between 1,000 and 2,000 A and a pore volume of at least 0.9 cm³/g and in which quaternary alkyl amine or alkyl alkanoamine groups, preferably alkyl alkanoamine groups, are attached to the styrene- divinyl-benzene-polymer matrix, and which has a par¬ ticle diameter between 300 and 600 μm, and the fraction leaving the column is recovered. Preferably, whey or whey protein solution in a corresponding amount with respect to the protein, treated at process stage a), is passed at process stage b) at a pH ranging between 6.0 and 7.0 at a flow rate of 3 to 5 column volumes per hour through a chromatography column packed with a strong polystyrene-based anion exchange resin so that 6 to 7 cm³ of whey or whey protein solution in a corresponding amount with respect to the protein are passed through the column per 1 cm³ of resin.

After clarified whey or whey protein solution has been passed at process stage b) through the column packed with the strong anion exchange chromatography resin Diaion HPA 25 or Diaion HPA 75, the β-LG con¬ centration of the whey solution passed through the column has decreased significantly and its main pro- tein component is α-LA.

At process stage c), the anion exchange resin column treated at stage b) is washed with deionized water, the wash water is combined with the fraction recovered at process stage b) and the obtained solu- tion is recovered as an alpha-lactalbumin component.

The recovered alpha-lactalbumin component can be used as such as an α-LA component particularly in infant food formulas or it can be concentrated and, if desired, dried in a manner known per se before use as an α-LA component.

At process stage d), β-LG bound to the resin column can be released from the washed anion exchange resin column by eluting with a weak aqueous NaCl solu¬ tion, preferably an aqueous 2 to 5 wt.% NaCl solution, and the eluate is recovered as a beta-lactoglobulin component. After having been rinsed with water, the resin is ready for re-use.

The recovered beta-lactoglobulin component can be used as such as a β-LG component e.g. in clinical nutritive preparations or various products of the food industry. It can also be concentrated and, if desired, dried in a manner known per se before use as a β-LG component.

Cheese whey usually contains glycomacropeptide (GMP) formed from milk casein in the production of cheese as a result of the action of a rennet enzyme. On separating the cheese mass, GMP remains in whey. It has been found that GMP deteriorates protein fraction- ation with ion exchange resins [P.J. Skudder, J. Dairy Res . , 52 (1985) 167 - 181] and that it may even cause blocking of Spherosil QMA resin. In GB Patent Appli¬ cation 2,188,526, J. Burton and P.J. Skudder describe a process utilizing Spherosil QMA for removing GMP.

It has now been unexpectedly found that GMP can be removed from whey or whey protein solution qualit¬ atively, as it can be made to attach to the strong anion exchange resin Diaion HPA 25 or HPA 75 at pH 5.0.

Glycomacropeptides possibly present in whey or whey protein solution at stage a) of the process according to the invention are thus removed by passing clarified whey or whey protein solution at pH 5.0 at a flow rate of 3 to 7 column volumes per hour through a chromatography column packed with strong polystyrene- based anion exchange resin, which resin has a great pore size between 1,000 and 2,000 A and a pore volume of at least 0.9 cm³/g and in which quaternary alkyl amine or alkyl alkanoamine groups, preferably alkyl alkanoamine groups, are attached to the styrene- divinyl-benzene-polymer matrix, and which has a par¬ ticle diameter between 300 and 600 μm, so that 7 to 10 cm³ of whey or whey protein solution in a correspond¬ ing amount with respect to the protein are passed through the column per 1 cm³ of resin, and the fraction leaving the column is passed to stage b). In this way, whey or whey protein solution free of GMP is obtained.

Fractionation of whey proteins from cheese whey or cheese whey protein solution purified from GMP is significantly more efficient than from unpurified cheese whey or cheese whey protein solution, and no problems are caused by blocked columns.

In the process according to the invention, GMP can be removed considerably more economically than in the above-mentioned known process, as the expensive Spherosil QMA resin can now be replaced with the Diaion HPA 25 or HPA 75 resins, which are markedly cheaper. Moreover, HC1 can be replaced with a NaCl solution in eluting Diaion HPA 25 or HPA 75 resins. The invention also relates to an alpha-lact¬ albumin component which is useful as an α-LA component particularly in infant food formulas and which is produced by the process according to the invention.

Furthermore, the invention relates to a beta- lactoglobulin component which is useful as a β-LG protein component in the food industry in the produc¬ tion of e.g. clinical nutritive preparations and dif¬ ferent kinds of food products, such as various drinks, sausages and ice-creams, and which is produced by the process according to the invention. Example 1

The pH of casein whey (2,000 cm³) was adjusted between 7.5 and 8.5, and the whey was warmed for 30 min at 50°C, after which it was allowed to stand for 16 h at 5°C. Clear whey was separated from the pre¬ cipitated calcium phosphate, fat and lipoproteins through decantation. Clarified whey was additionally filtered through Whatman GF/A filter paper and stored at 5°C. 30 cm³ of regenerated, strong anion exchange resin Diaion HPA 25 were packed into a chromatography column. 200 cm³ of casein whey clarified as described above were passed through the resin column at a rate of 100 cm³/h at pH 6.5. The column was washed with 60 cm³ of deionized water (100 cm³/h) until the absorbance of the solution at the wave length of 280 nm was 0 (the solution no longer contained any protein) . Whey leaving the column and the wash water were combined (alpha fraction). Protein attached to the column was eluted with a 2 to 5 wt.% NaCl solution (50 cm³, 100 cm³/h) until the absorbance of the solution at the wave length of 280 nm was 0 (beta fraction). The column was rinsed with deionized water until the wash water no longer contained salt. After this the column was ready for re-use. The compositions of the fractions are shown in Table 1. Example 2

This example is identical with Example 1 except that the material precipitated in the clarification of whey was separated from whey by centrifugation (4,200 g, 20 min), and the resin was Diaion HPA 75. Table 1 shows data on the composition of the α and β frac¬ tions. Figure 1 shows the FPLC chromatograms of the α and β fractions obtained by liquid chromatography (column: Superdex 75, Pharmacia). The numerical values given in the figure indicate the retention time, A = immunoglobulins, B = bovine serum albumin (BSA), C = β-LG, D = α-LA, E = orotic acid. Example 3 30 cm³ of regenerated, strong anion exchange resin Spherosil QMA LS were packed into a chromato¬ graphy column. 200 cm³ of casein whey clarified as described in Example 2 were passed through the resin column at a rate of 100 cm³/h at pH 6.5. The column was washed with 60 cm³ of deionized water (100 cm³/h) until the absorbance of the solution at the wave length of 280 nm was 0. Whey leaving the column and the wash water were combined (alpha fraction). Protein attached to the resin column was eluted with a 0.1 N HC1 solution (50 cm³, 100 cm³/h) and rinsed with deionized water until the protein concentration of the eluate was 0 (beta fraction). The column was further rinsed until the pH of water leaving the column was more than 4.0, after which the column was ready for re-use. Table 1 shows the compositions of the fractions. Figure 2 shows the FPLC chromatograms of the α and β fractions obtained by liquid chromato¬ graphy (column: Superdex 75, Pharmacia). The numerical values given in the figure indicate the retention time, A = immunoglobulins, B = bovine serum albumin (BSA), C = β-LG, D = α-LA, E = orotic acid.

Table 1

Compositions of protein fractions produced as described in Examples 1 to 3

QMA LS HPA 25 HPA 75 α-LA β-LG α-LA β-LG α-LA β-LG

(mg) (mg) (mg) (mg) (mg) (mg)

Casein whey 98 419 101 432 122 462

(feed) α-fraction 32 20 92 116 95 44 β-fraction 66 500 7 340 28 403

Yield (%) * 100 124 98 106 101 97

*) = ((Protein in α-fraction + β-fraction)/Protein in feed) -100%

It appears from the results that Spherosil QMA

LS bound proteins most efficiently; only 5% of β-LG and 33% of α-LA was eluted in the alpha fraction, in which α-LA : β-LG = 1 : 0.63. In the beta fraction, α-LA : β-LG = 1 : 7.6. Diaion HPA resins bound pro- teins much more selectively: HPA 25 admitted 91% and HPA 75 78% of α-LA directly into the alpha fraction, whereas 79% of β-LG was bound when HPA 25 was used and 87% when HPA 75 was used (HPA 25: alpha fraction: α-LA : β-LG = 1 : 1.3; HPA 75: alpha fraction: α-LA : β-LG = 1 : 0.5). The alpha fraction obtained by Diaion HPA 75 was thus of higher quality and had a higher yield than that obtained by Spherosil QMA LS. Example 4 8.8 g of CaCl₂*2H₂0 were added to cheese whey

(2,000 cm³), and the whey was adjusted to pH 7,3 with 1 N NaOH. The whey was warmed at 50°C for 8 min and allowed to stand at 5°C for 16 h, after which the clear whey was separated from the phospholipid pre- cipitate by decanting. Clarified whey was filtered through Whatman GF/A filter paper.

Whey (300 cm³) clarified as described above was passed through a Diaion HPA 75 resin column (30 cm³) at 100 cm³/h at pH 5.0. On leaving the column, the whey contained less than 20% of the original GMP. The α-LA concentration was unaffected by the treatment; less than 9% of the beta-lactoglobulin contained in the feed remained in the resin. GMP attached to the resin was eluted with a 4-wt.% NaCl solution, and salts were washed off the resin by deionized water. The resin was ready for re-use. Example 5

Cheese whey was clarified as described in Example 4, except that the phospholipoprotein pre- cipitate was separated from the whey by centrifug- ation. Whey so clarified (300 cm³) was passed through a Spherosil QMA LS resin column (30 cm³) at 100 cm³/h at pH 5.0. On leaving the column, the whey contained less than 20% of the original GMP. Altogether 17% of α-LA and β-LG attached to the resin. GMP attached to the resin was eluted by 0.1 N HCl solution, and the resin was washed by deionized water until the pH of the wash water leaving the column exceeded 4.0. The resin was ready for re-use.

Table 2

Protein balances of Examples 4 and 5

QMA LS HPA 75 α-LA β-LG α-LA β-LG

(mg) (mg) (mg) (mg)

Feed 188 422 228 819

Whey fraction¹' 177 374 235 742

GMP fraction ND²' ND 8 21

Protein loss

(%) ³' 6 11 0 9

¹¹ whey from which GMP has been removed

²⁾ ND = not determined

³⁾ Amount of alpha-lactalbumin and beta-lactoglobulin in the GMP fraction

It appears from the results that GMP can be separated relatively selectively with both resins. Protein losses were rather small.

Example 6

200 cm³ of cheese whey from which GMP had been removed as described in Example 4 were passed through Diaion HPA 75 resin (30 cm³) at a rate of 100 cm³/h at pH 6.5, after which the resin was rinsed with de¬ ionized water until the absorbance of the solution at the wave length of 280 nm was 0. Whey passed through and wash water were combined (alpha-lactalbumin fraction). Protein attached to the resin was eluted with a 5 wt.-% NaCl solution (50 cm³) (beta-lacto¬ globulin fraction). Table 3 shows the compositions of the fractions.

Example 7

295 cm³ of cheese whey from which GMP had been removed as described in Example 5 were passed through Spherosil QMA LS resin (30 cm³) at a rate of 100 cm³/h at pH 6.5, whereafter the resin was rinsed with de¬ ionized water until the solids of the solution leaving the column were 0. The whey passed through and the wash water were combined (alpha-lactalbumin fraction). Protein attached to the resin was eluted with a 0.1 N HCl solution (50 cm³) (beta-lactoglobulin fraction). The compositions of the fractions are shown in Table 3.

Table 3

Compositions of protein fractions produced as described in Examples 6 and 7

QMA LS HPA 75 α-LA β-LG α-LA β-LG

(mg) (mg) (mg) (mg)

Feed 177 374 132 366 α-fraction 117 46 97 51 β-fraction 46 314 66 396

Yield (%) 92 96 123 122

The removal of GMP significantly improved the fractionation of proteins with both resins.

Example 8

Phospholipoproteins were removed from cheese whey by microfiltration through a 1.4-μm membrane. 60 cm³ of the whey so clarified were passed through 30 cm³ of strong anion exchange resin Duolite A 101 (Rohm & Haas, France) regenerated into Cl'-form at a rate of 150 cm³/h at pH 5, 6, 7 and 8. At each pH, the whey was circulated through the resin for 30 min. The experiments were conducted at room temperature. After circulation, 100 cm³ of ion-exchanged water were passed through the column, and the wash water was combined with the whey fraction (alpha-fraction). Protein attached to the column was eluted with 0.1 N HCl (beta-fraction).

Table 4

Compositions of protein fractions produced as described in Example 8

pH 5.0 pH 6.0 pH 7.0 pH 8.0 α-LA β-LG α-LA β-LG α-LA β-LG α-LA β-LG

(mg) (mg) (mg) (mg) (mg) (mg) (mg) (mg)

Feed 47 149 46 152 52 155 45 149 α-fr. 50 147 46 151 46 148 44 149 β-fr. 0 2 0 1 6 8 1 0

It appears from the results that Duolite A101 virtually bound no protein, being thus unsuitable for protein fractionation.

Claims

Claims :

1. Process for fractionating whey or whey protein solution chromatographically selectively into an alpha-lactalbumin component and a beta-lacto¬ globulin component, c h a r a c t e r i z e d by a) clarifying a batch of whey or whey protein solution and, if required, removing glycomacropeptides from it; b) passing whey or whey protein solution treated at stage a) through a chromatography column packed with a strong polystyrene-based anion exchange resin, which resin has a great pore size ranging between 1,000 and 2,000 A and a pore volume of at least 0.9 cm³/g and in which quaternary alkyl amine or alkyl alkanoamine groups, preferably alkyl alkanoamine groups, are attached to a styrene-divinyl-benzene- polymer matrix, and which has a particle diameter between 300 and 600 μm, and recovering the fraction leaving the column; c) washing the anion exchange resin column treated at stage b) with deionized water, the wash water being combined with the fraction recovered at stage b), and the obtained solution being recovered as an alpha-lactalbumin component; which is followed by d) eluting the washed anion exchange resin column with a weak aqueous NaCl solution and recover¬ ing the eluate as a beta-lactoglobulin component.

2. Process according to claim 1, c h a r a c- t e r i z e d in that glycomacropeptides possibly present in whey or whey protein solution are removed at stage a) by passing clarified whey or whey protein solution at pH 5.0 at a flow rate of 3 to 7 column volumes per hour through a chromatography column packed with strong polystyrene-based anion exchange resin, which resin has a great pore size ranging be¬ tween 1,000 and 2,000 A and a pore volume of at least 0.9 cm³/g and in which quaternary alkyl amine or alkyl alkanoamine groups, preferably alkyl alkanoamine groups, are attached to a styrene-divinyl-benzene- polymer matrix, and which has a particle diameter between 300 and 600 μm, so that 7 to 10 cm³ of whey or whey protein solution in a corresponding amount with respect to the protein are passed through the column per 1 cm³ of resin, and the fraction leaving the column is passed to stage b).

3. Process according to claim 1 or 2, c h a r¬ a c t e r i z e d by treating whey or whey protein solution which is cheese whey, casein whey, de- mineralized whey or whey protein concentrate.

4. Process according to any of claims 1 to 3, c h a r a c t e r i z e d in that whey or whey pro¬ tein solution is clarified by precipitating residual casein, phospholipoproteins and calcium phosphate possibly present in it by adjusting it to a pH value of at least 7.3 by adding 4.4 g of CaCl₂*2H₂0 per one litre of whey and heating lightly and removing the resulting precipitate by decantation, centrifugation or microfiltration.

5. Process according to any of claims 1 to 4, c h a r a c t e r i z e d in that whey or whey pro¬ tein solution in a corresponding amount with respect to the protein, treated at stage a), is passed at stage b) at a pH ranging between 6.0 and 7.0 at a flow rate of 3 to 5 column volumes per hour through a chromatography column packed with a strong poly¬ styrene-based anion exchange resin so that 6 to 7 cm³ of whey or whey protein solution in a corresponding amount with respect to the protein are passed through the column per 1 cm³ of resin.

6. Process according to any of claims 1 to 5, c h a r a c t e r i z e d in that the anion exchange resin is eluted at stage d) with an aqueous 1 to 5 wt.% NaCl solution.

7. Process according to any of claims 1 to 6, c h a r a c t e r i z e d in that the alpha-lact¬ albumin component recovered at stage c) is concen¬ trated and possibly dried.

8. Process according to any of claims 1 to 7, c h a r a c t e r i z e d in that the beta-lacto¬ globulin component recovered at stage d) is con¬ centrated and possibly dried.

9. Alpha-lactalbumin component for use in infant food formulas, c h a r a c t e r i z e d in that it is prepared by a process according to any of claims 1 to 7.

10. Beta-lactoglobulin component for use as a protein component in the food industry, c h a r a c¬ t e r i z e d in that it is prepared by a process according to any of claims 1 to 6 and 8.