JP3050483B2 - Whey protein-containing solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a whey protein-containing liquid which can be kept substantially transparent even by heating or addition of salt.

[0002]

BACKGROUND OF THE INVENTION Whey is the name of the fraction obtained by removing casein from milk, and the main protein components are β-lactoglobulin, α-lactalbumin and serum albumin. Since it is obtained in large quantities as a secondary product of dairy processing, is economically available, and has excellent palatability, it has recently become widely accepted in the food market as a whey beverage or whey powder. It has become.

[0003] Furthermore, whey protein is widely used as a raw material for food processing because it has excellent functions such as gel-forming ability, foam properties and emulsifying properties. However, since heating the whey protein results in a cloudy liquid or cloudy gel, it cannot be applied to liquid or gel foods that require transparency,
Its use was limited. So far, polysaccharides such as agar, alginic acid, pectin, and animal proteins such as gums and gelatin have been mainly used as protein-based transparent gelling agents and thickeners for confectionery, etc. Sex, functionality,
There was an inadequate aspect in nutrition.

[0004] Examples of the transparent gel base material include egg white subjected to alkali treatment, food protein (eg, albumin albumin) treated with proteolytic enzyme, and egg white subjected to desalting treatment. However, alkali treatment causes a decrease in protein nutrition, and enzymatic treatment requires a large amount of expensive enzyme agents and is uneconomical, and desalted egg white is transparent in neutral and weakly acidic pH regions. There are many problems, such as the inability to maintain sex. In these methods, in any case, when heated in the presence of salts, a turbid gel or a turbid liquid is formed, and the turbid liquid has low viscosity, and its use as a thickener is limited. Low emulsifying power and foaming property. Also,
Cloudy gels have many problems such as poor water retention and elasticity.

[0005]

SUMMARY OF THE INVENTION As described above, the present invention provides a whey protein which is excellent in economy and functionality.
By producing products that can be maintained stably and transparently even without heating, even with reduced nutrition, etc., to expand the use of whey protein to foods, cosmetics, pharmaceuticals, etc. Make it an issue. It is another object of the present invention to provide a transparent whey protein-containing liquid that can form a substantially transparent viscous liquid or gel under salt-containing conditions or at a low protein concentration.

[0006]

According to the present invention, whey protein has an ionic strength of 25 millimoles (mM) or less, a protein concentration of 6.5 to 12%, and a pH of 3.5 or less.
By using a transparent whey protein-containing liquid of 5 or more, it was found that a product was obtained that maintained transparency even when 50 mM of sodium chloride was added thereto and heated.

That is, in the present invention, after the whey protein is purified, the whey protein-containing solution is substantially salt-free (ionic strength of 25 mM or less) at a pH of 3.5 or less or 6.5 or more. By heating to 55 ° C. or more, it became possible to obtain a practical transparent viscous liquid or gel that does not deteriorate even by subsequent heating or addition of salt.

[0008] Whey is obtained in large quantities, for example, as a by-product of the cheese manufacturing process. In the present invention, low-molecular compounds such as salts and saccharides contained in the whey are substantially removed. Thereafter, the pH of the solution is adjusted to a value away from the isoelectric point (around pH 5) of whey protein, pH 3.5 or lower, or pH 6.5 or higher, or heat treatment is performed after such pH adjustment. Thus, a transparent liquid or gel-like product can be obtained.

In the present invention, the term "transparent" includes translucent materials, and generally includes a spectrophotometer UV manufactured by Shimadzu Corporation.
Absorbance measured at 160A is 1.5 or less (however, wavelength 600nm,
Glass cell having an optical path length of 1 cm).

[0010] The whey protein used in the present invention is any of whey and a whey protein fraction obtained therefrom, and its major proteins (β-lactoglobulin, α-lactalbumin, serum albumin, etc.). There may be.

In the present invention, methods for purifying whey protein include dialysis using water or a low concentration buffer, electrodialysis, chromatography (ion exchange, gel chromatography, hydrophobic chromatography, etc.), microfiltration. , Electrophoresis, adsorption separation, precipitation separation, etc., may be used, and two or more of these may be used in combination. In any case, it is necessary to be in a substantially salt-free state with an ionic strength of 25 mM or less.

The liquid to be subjected to the heat treatment in the present invention may contain salt or the like for seasoning.
Need to be done after pH adjustment. When a salt or the like is added, it becomes easy to become cloudy due to the heat treatment.
Is particularly preferably adjusted to 3.5 or less or 6.5 or more.

When the heat treatment is performed, the whey protein content of the liquid is 6.5 to 12% by weight. In a low protein concentration range, the liquid becomes a transparent liquid even after heating, and shows a viscous liquid. When the concentration is increased, it becomes a viscous liquid and becomes difficult to handle. In general, the salt concentration that may be contained in such a liquid is preferably 200 mM or less, particularly 150 mM or less from the viewpoint of the taste of the product.

Although the heating temperature in the present invention is not particularly limited, it is generally preferably 55 ° C. or higher, and generally about 75 to 95 ° C. is easy to handle. However, the gel may be heated to 100 ° C. or higher. For example, when heated at about 120 ° C., a harder gel having higher elasticity than a gel obtained by heating at 100 ° C. or lower can be obtained.

[0015]

EXAMPLE 1 The fat content of milk was removed by centrifugation, and the resulting solution was centrifuged.
The pH was adjusted to 4.5 and the precipitated casein fraction was removed by centrifugation to obtain whey. Then, the whey was dialyzed against water to obtain a clear whey protein solution. This treatment removes low molecular compounds such as salts and saccharides. In addition, a precipitate was formed by dialysis, but no significant change was observed in the composition of whey protein even if the precipitate was removed by centrifugation. The pH of the obtained supernatant was adjusted to 3.5 and 6.5, the protein concentration was adjusted to 7%, and the mixture was heated to 80 ° C. Normally, whey or protein solution becomes cloudy when heated under these conditions, but the dialysed whey protein of this example is
A clear liquid was obtained without turbidity even after heating. The viscosity of the solution depended on the protein concentration, and as the protein concentration increased, the solution became a viscous solution, but the transparency of the solution was maintained at this time.

Example 2 In the same manner as in Example 1, water was sufficiently dialyzed to obtain a clear whey protein solution. This whey protein solution is divided into three equal parts, each pH is adjusted to 3.5, 7.0, 8.5 using 2N sodium hydroxide or hydrochloric acid. And the sodium chloride concentration is 5
After adjusting to 0 mM, the mixture was heated at 80 ° C. for 1 hour. As a result, all gels were obtained, but the pH was 3.5 and 7.0.
Is a translucent gel, pH 8.5 is a transparent gel,
It did not become a conventional cloudy substance.

Example 3 In the same manner as in Example 1, water was sufficiently dialyzed against water to obtain a clear whey protein solution. The pH of the whey protein solution was adjusted to 7.5, the protein concentration was adjusted to 12%, and the sodium chloride concentration was adjusted to 50 mM.
Heated at ° C for 4 minutes. As a result, a transparent gel much harder and more elastic than the transparent gel produced in Example 2 could be obtained.

Example 4 In the same manner as in Example 1, water was sufficiently dialyzed to obtain a clear whey protein solution. The pH of the whey protein solution was adjusted to 5.5 and 7.0, the protein concentration was adjusted to 3%, and the mixture was heated at 80 ° C. for 1 hour. As a result, a viscous cloudy liquid was obtained at pH 5.5, and a viscous transparent liquid was obtained at pH 7.0. All exhibited high viscosities.

Example 5 In the same manner as in Example 1, water was sufficiently dialyzed against water to obtain a clear whey protein solution. The pH of the whey protein solution was adjusted to 5.5 and 7.0, the protein concentration was adjusted to 7%, and the mixture was heated at 80 ° C. for 1 hour. As a result, a cloudy gel was obtained at pH 5.5, and a transparent gel was obtained at pH 7.0. Each gel was soft, and a paste could be obtained by crushing the gel after formation.

Example 6 In the same manner as in Example 1, water was sufficiently dialyzed to obtain a clear whey protein solution. The pH of the whey protein solution was adjusted to 5.5 and 7.0, the protein concentration was adjusted to 12%, and the mixture was heated at 80 ° C. for 1 hour. As a result, a cloudy gel was obtained at pH 5.5, and a transparent gel was obtained at pH 7.0. Each gel was hard, rich in elasticity, and excellent in water retention.

Example 7 In the same manner as in Example 1, water was sufficiently dialyzed against water to obtain a clear whey protein solution. This whey protein solution is divided into three equal parts, and their pH is adjusted to 3.5, 7.0 and 8.5 using 2N sodium hydroxide or hydrochloric acid,
At the same time, after adjusting the protein concentration of each solution to 7% and the sodium chloride concentration to 150 mM, the solution was heated at 80 ° C. for 1 hour. As a result, the pH 3.5 preparation was a translucent gel, pH 7.0 and
The sample of 8.5 became a cloudy gel.

Example 8 Whey obtained in the same manner as in Example 1 was dialyzed against a buffer and centrifuged to obtain a clear supernatant. Using this supernatant, that is, whey protein as a starting material, β-lactoglobulin, which is a main component of whey protein, was prepared using ion exchange chromatography and gel chromatography. After sufficiently dialyzing the obtained β-lactoglobulin against distilled water, the pH was adjusted to 2 to 9
The pH was adjusted every 0.5 pH unit. All protein concentrations were adjusted to 6.5%. When this solution was heated at 90 ° C. for 1 hour, a transparent gel was obtained at pH 3.5 or lower, and pH 6.5.
A clear solution was obtained at 5 to 7.5, and a clear gel was obtained at pH 8.5.
Similar experiments were performed using commercially available β-lactoglobulin. In this case, the same results were obtained.

Example 9 β-lactoglobulin obtained by the same method as in Example 8 was sufficiently dialyzed against distilled water, and the pH was adjusted from 2 to 9 to 0.2.
The adjustment was made every 5 units. In addition, sodium chloride was added to each pH product so that the final concentration was 50 mM, and at the same time, the protein concentration was adjusted to 6.5%. 90 ℃
For 1 hour, a translucent gel was formed at pH 3.5 or less. Further, when the pH was between 3.5 and 6.5, a cloudy gel or a cloudy liquid was obtained.

Example 10 After β-lactoglobulin obtained by the same method as in Example 8 was sufficiently dialyzed against distilled water, the pH was adjusted from 2 to 9 to 0.1.
The adjustment was made every 5 units. Further, sodium chloride was added to each pH product so that the final concentration became 100 mM, and at the same time, the protein concentration was adjusted to 6.5%. 90
Heating at 1 ° C. for 1 hour formed a translucent gel at pH 3.5 or lower. When the pH was 3.5 to 8.5, the mixture became a cloudy gel or a cloudy solution, and formed a translucent gel in a pH range of 9 or more.

Example 11 Bovine serum albumin (fraction V sample, manufactured by Sigma), which is one of whey-derived proteins, is sufficiently dialyzed against distilled water, and then the pH is adjusted to 0.2 to 0.9. Adjustments were made every 5 units, and at the same time all protein concentrations were adjusted to 7%. When this solution was heated at 90 ° C for 1 hour, pH
2 and 2.5 are clear liquids, pH 3 and 3.5 are translucent gels,
At pH 4 to 6.5, it became a cloudy gel or cloudy solution, and at pH 7 or higher, it became a clear solution.

Example 12 Serum albumin obtained by the same method as in Example 8 was sufficiently dialyzed against distilled water, and then the pH was adjusted from 2 to 9 in 0.5 unit increments. Adjusted to 7%. Sodium chloride was added to each of the samples thus obtained to a final concentration of 50 mM, and 90 ° C.
When heated for 1 hour at pH 2 and 2.5, clear gel,
At pH 3 and 3.5, it became a cloudy gel, and at pH 4 to 6.5, it became a cloudy gel or a cloudy solution, but at pH 7 or more, it became a translucent gel.

Example 13 The whey protein solution obtained by dialysis in the same manner as in Example 1 was adjusted to have a pH of 7 and a protein concentration of 7%.
After the addition of salt as shown in the following table, the product was heated at 80 ° C. for 1 hour, and the transparency of the product was measured by absorbance with a spectrophotometer UV160A manufactured by Shimadzu Corporation. The results are shown in the following table. . NaCl amount (mM) Absorbance State of the product . (1) 0 0.037 Transparent. (2) 30 0.449 Transparent. (3) 40 0.592 Transparent. (4) 50 1.336 translucent. (5) 100 2.3 or more cloudy. (6) 200 2.3 or more cloudy

Example 14 Bovine serum albumin (fraction V sample manufactured by Sigma) was sufficiently dialyzed against distilled water to adjust the pH of the obtained solution to 7, and at the same time, the protein concentration to 6. After adjusting the solution to 5, salts were added to this solution as shown in the following table, and the solution was heated at 80 ° C. for 1 hour. The following Table shows the results of measuring the transparency of the obtained product by measuring the absorbance with a spectrophotometer UV160A manufactured by Shimadzu Corporation. . NaCl amount (mM) Absorbance State of the product . (1) 0 0.329 Transparent. (2) 50 0.592 Transparent. (3) 100 2.3 or more cloudy

Example 15 The same method as in Example 14 was carried out using β-lactoglobulin. As a result, a transparent product was obtained without sodium chloride and 50 mM as in Example 10. , 100 mM did not give a clear product.

Example 16 The whey protein obtained in the same manner as in Example 1 was dialyzed against water, and the clear liquid having a protein concentration of 7% was adjusted to pH 3 and 9. At this time, a clear viscous sol was obtained.

Example 17 The fat content of milk was removed by centrifugation.
The pH was adjusted to 4.5 and the precipitated casein fraction was further removed by centrifugation to obtain whey. This whey is dialyzed against water,
Whey protein was obtained. This treatment removes low molecular compounds such as salts and saccharides. Further, a precipitate is formed by dialysis, and the precipitate is removed by centrifugation. It should be noted that no significant change was found in the whey protein composition by such treatment. The obtained supernatant was adjusted to a protein concentration of 7% and a pH of 7, and heated at 80 ° C. for 1 hour. The pH of the clear liquid thus obtained, that is, the processed whey protein product, was adjusted from 2 to 9 in increments of 0.5 pH unit, and sodium chloride was added to a final concentration of 50 mM. When this liquid was reheated at 90 ° C. for 1 hour, the product adjusted to pH 3.5 or lower was kept as a clear liquid, whereas the product adjusted to pH 4 to 6.
The product of No. 5 became a cloudy gel or a cloudy liquid, and became a transparent gel at pH 7 or more.

Example 18 The protein concentration of whey obtained in the same manner as in Example 17 was 7
%, PH was adjusted to 7, and heated at 80 ° C. for 1 hour. As a result, a transparent liquid whey protein processed product was obtained. The pH of the solution was adjusted from 2 to 9 in 0.5 pH increments, and sodium chloride was added to a final concentration of 100 mM. The liquid having increased viscosity was further added to the solution at 90 ° C.
For 1 hour, translucent gel up to pH 3.5, pH 4
From 6.5 to 6.5, a cloudy gel or cloudy liquid was obtained, but at a pH higher than that, a transparent or translucent gel was obtained.

Example 19 The whey obtained in the same manner as in Example 17 was dialyzed against distilled water and centrifuged to obtain a supernatant. The protein concentration of this clear solution was adjusted to 7% and the pH to 7, and at 80 ° C.
The mixture was heated for a period of time to obtain a processed whey protein product. The pH of the processed whey protein product was adjusted to 6.5, 7.5, 8.5, and sodium chloride was added to a final concentration of 100 mM.
Heat at 121 ° C. for 4 minutes. As a result, in each case, a transparent gel was formed, and this transparent gel was harder and more elastic than the transparent gel of Example 2 obtained by heating at 90 ° C.

Example 20 Whey obtained in the same manner as in Example 17 was dialyzed against a buffer and centrifuged to obtain a supernatant. From this supernatant, β-lactoglobulin, the main component of whey protein, was prepared by ion exchange chromatography and gel chromatography. Of the resulting β-lactoglobulin solution
The pH was adjusted to 7, heated at 80 ° C for 1 hour, and hydrochloric acid or caustic soda was added to the obtained clear solution, and the pH was adjusted from 2 to 9 in 0.5 pH units to a final concentration of 50 mM. Sodium chloride was added. When this solution was reheated at 90 ° C. for 1 hour, pH 3.5 or lower was a translucent gel, pH 4 to 6
Until the above, a cloudy gel was obtained, and at pH 6.5 or more, a transparent gel was obtained.
A similar experiment was performed using a commercially available β-lactoglobulin. In this case, similar results were obtained.

Example 21 The whey obtained in the same manner as in Example 17 was treated in the same manner as in Example 20, to obtain β-lactoglobulin. The clear solution of β-lactoglobulin was adjusted to pH 7 and heated at 80 ° C. for 1 hour, and hydrochloric acid or caustic soda was added to the obtained clear solution.
The pH was adjusted from 2 to 9 in 0.5 pH increments, and the protein concentration was adjusted to 6.5%, after which sodium chloride was added to each solution to a final concentration of 100 mM. When this solution was reheated at 90 ° C. for 1 hour, a translucent gel was obtained at pH 3.5 or lower, a cloudy gel from pH 4 to pH 6, and a translucent gel at pH 6.5 or higher. A similar experiment was performed using a commercially available β-lactoglobulin. In this case, similar results were obtained.

Example 22 Bovine serum albumin, a major protein of whey protein (fraction V sample, manufactured by Sigma) was used.
After sufficient dialysis against distilled water, the pH of the resulting solution was adjusted from 2 to 9 in 0.5 unit increments, and at the same time, the protein concentration was adjusted to 7%. Thereafter, the solution was heated at 80 ° C. for 1 hour, and hydrochloric acid or caustic soda was added to the obtained clear solution to adjust the pH from 2 to 9 in 0.5 pH steps so that the final concentration was 50 mM. Sodium chloride was added. When this solution was reheated at 90 ° C. for 1 hour, a transparent gel was formed at pH 3.5 or lower, a cloudy gel from pH 4 to pH 6, and a transparent gel at pH 6.5 or higher.

Example 23 Bovine serum albumin, one of the main proteins of whey protein (fraction V sample manufactured by Sigma) was used.
After sufficient dialysis against distilled water, the pH of the resulting solution was adjusted from 2 to 9 in increments of 0.5 pH units, and at the same time the protein concentration was adjusted to 7%. This liquid was heated at 80 ° C. for 1 hour, and hydrochloric acid or caustic soda was added to the obtained clear liquid.
Adjust the pH from 2 to 9 in 0.5 pH increments to a final concentration of 1
Sodium chloride was added to be 00 mM. When this solution was reheated at 90 ° C. for 1 hour, a transparent gel was formed at pH 3.5 or lower, a cloudy gel from pH 4 to pH 6, and a transparent gel at pH 6.5 or higher.

Example 24 The pH of a whey protein solution obtained by dialysis in the same manner as in Example 17 was adjusted to 7, and the mixture was heated at 80 ° C. for 1 hour. Adjust to a final concentration of 0-200 mM
Sodium chloride is added at different concentrations so that
This solution was reheated at 90 ° C. for 1 hour. The transparency of the product thus obtained was measured using a spectrophotometer manufactured by Shimadzu Corporation for UV1.
Measured at 60A. The results are shown in the following table. . NaCl amount (mM) Absorbance State of the product . (1) 0 0.022 Transparent. (2) 30 0.241 Transparent. (3) 40 0.271 Transparent. (4) 50 0.325 Transparent. (5) 100 1.308 translucent. (6) 200 2.3 or more Opaque

Example 25 After bovine serum protein (fraction V sample manufactured by Sigma) was sufficiently dialyzed against distilled water, the pH of the solution was adjusted to 7, and the protein concentration of the solution was simultaneously adjusted. Adjusted to 6.5%. After heating this solution at 80 ° C. for 1 hour, the pH of the obtained clear solution was adjusted to 7, and sodium chloride was added at a different concentration so that the final concentration was 0 to 200 mM. Reheated at 0 ° C. for 1 hour. The transparency of the product thus obtained was measured using a spectrophotometer (manufactured by Shimadzu Corporation) with a UV of 160.
A. The results are shown in the following table. . NaCl amount (mM) Absorbance State of the product . (1) 0 0.293 Transparent. (2) 50 0.380 Transparent. (3) 100 0.532 Transparent. (4) 150 0.580 Transparent. (5) 200 0.591 Transparent

Example 26 The same method as in Example 24 was carried out using β-lactoglobulin. As a result, as in Example 24, when sodium chloride was added in the range of 0 to 200 mM, transparent heat-processed products could be obtained in each case.

[0041]

According to the present invention, whey protein, which is economically easily available in large quantities, can be stably supplied to the market as a transparent liquid, and the transparent liquid can be safely and promptly supplied to consumers. It is possible to finish it into a processed product with a practicality and finish it into a processed whey protein product that is practical. Furthermore, whey protein can be processed safely and quickly into a transparent heat-processed product, even with salt added.Whey protein rich in nutrients can be used for food, cosmetics, pharmaceuticals, etc. with good appearance. Widely applicable.

Continuation of the front page (56) References JP-A-4-228036 (JP, A) Journal of Food Processing and Preservation (1978) Vol. 2, p. 111-121 Journal of the Japan Food Industry Association (1985) Vol. 9, p. 639-645 J.C. Dairy Sci. (1984) Vol. 67, no. 11, p. 2723−2733 (58) Field surveyed (Int.Cl. ⁷ , DB name) A23J 3/08 A23C 9/14-9/148 A23C 21/00-21/10

Claims (1)

(57) [Claims] 1. A transparent whey protein-containing solution having an ionic strength of 25 mmol or less, a protein concentration of 6.5 to 12%, and a pH of 3.5 or less or 6.5 or more, and adding 50 mmol of sodium chloride. A whey protein-containing liquid, which is a product that maintains transparency even when heated.