JPS61265052A - Production of transparent egg white gel - Google Patents

Abstract

PURPOSE:To gelatinize protein in the egg white without opacitying and insolubilizing and obtain the titled substance useful for a food requiring transparency, by gelatinizing a soluble denatured egg white protein in a specific concentration and specific pH conditions in the presence of a neutral salt. CONSTITUTION:A liquid of soluble denatured egg white protein in >=3wt% protein concentration, adjusted to >=6pH or <=4pH, and containing >=0.1wt% neutral salt, e.g. NaCl, is normally heated to >=50 deg.C and gelatinized to afford the aimed substance. The above-mentioned soluble denatured protein is obtained by heat-treating a liquid of egg white after removing lysozyme under conditions of 4wt% protein concentration, 10pH and 4ms/cm electric conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for producing transparent egg white gel.

BACKGROUND OF THE INVENTION Egg white has the property of gelling when heated and has high nutritional value as a protein, so it is widely used as a raw material for food processing. However, since the gel obtained by heating egg whites is cloudy, egg whites cannot be used in food products that require transparency and avoid cloudiness. Although it is desired to develop a method for producing transparent egg white gel that can be used in foods that require transparency, such research has not been carried out to date.

C6 Problems to be solved by the invention The inventors have
In view of this situation, we aimed to develop a method for producing transparent egg white gel, and as a result of intensive research on the mechanism of white clouding and gelation due to heating of egg white liquid, we found that the protein in egg white does not become cloudy and insolubilized. We found the conditions for gelatinization and succeeded in making transparent egg white gel.

Means for solving the twenty problems, that is, the present invention, is to prepare soluble denatured egg white protein with a protein concentration of 3% by weight or more, a pH of 6 or more or a PT (4 or less), and a neutral salt content of 0. The present invention relates to a method for producing a transparent egg white gel, which is characterized by gelling under conditions containing 1% by weight or more, and the details will be explained below. A soluble denatured egg white protein liquid obtained by heating an egg white protein liquid to 60C or higher to denature the protein without making it cloudy and insolubilized, and freeze-drying or spray drying this soluble denatured egg white protein liquid. It is a powder obtained by

Here, the egg white proteinaceous liquid means an egg white proteinaceous liquid containing ovomarbucin as a main component, such as normal egg white liquid, a solution of egg white powder dissolved in water, egg white liquid after lysozyme removal,
Refers to egg white fluid after removing conalbumin, egg white fluid after removing lysozyme and conalbumin, and ovalbumin fluid.

In order to heat-denature the protein in the egg white protein solution, it is sufficient to heat it to a temperature higher than the sterilization temperature of the egg white, usually 60C or higher (hereinafter referred to as heat treatment).
Heat treatment results in a cloudy, insoluble state, so prior to heat treatment, the concentration of the egg white protein liquid must be lowered and the electrical repulsion between these proteins must be increased, or ovalbumin, which accounts for more protein, may be used. By increasing the ratio of sugar or sugar alcohol such as glucose, maldose, dextrin, glycerol, etc., it is possible to prevent the protein from becoming cloudy and insolubilized due to heat treatment. A liquid is obtained.

To reduce the protein concentration of the egg white proteinaceous liquid before heat treatment, the egg white proteinaceous liquid can be soaked in deionized water or
It can be diluted with deionized water containing sugar or sugar alcohol. The electrical repulsion between proteins should be increased to the extent that the pH of the egg white protein liquid is moved away from the isoelectric point specific to those proteins before heat treatment, or to the extent that the electrical conductivity of the egg white protein liquid is reduced before heat treatment. I can do it.

The pH may be adjusted using either a mineral acid or an organic acid, but it is usually adjusted using hydrochloric acid or sodium hydroxide.

The electrical conductivity can be lowered by diluting the egg white protein solution with deionized water or, if necessary, by dialysis.

Conditions such as protein concentration, sugar or sugar alcohol concentration, PH, and conductivity before heat treatment to obtain soluble denatured egg white protein from heat treatment G vary depending on the raw materials used as the egg white protein solution, but in any case, A soluble denatured egg white protein liquid can be prepared by selecting conditions that do not cause the protein to become cloudy and insolubilized when the temperature of the egg white protein liquid is set to 6 or higher or higher.

For example, when using a normal egg white liquid, a liquid prepared by dissolving egg white powder in water, or an egg white liquid after removing lysozyme as the egg white protein liquid, conduct electricity with PHIO at a protein concentration of 4% by weight before heat treatment. degree 4ms/am or
Conductivity 1 m at PH2.5 at protein concentration 3% by weight
s/cm or conductivity 4 m at pH 9 at a protein concentration of 4% by weight and a glucose concentration of 2% by weight.
A soluble denatured egg white protein liquid can be obtained by heat treatment under conditions of s/cm.

When using egg white liquid after removing conalbumin or egg white liquid after removing lysozyme and conalbumin as egg white protein, the protein concentration is 4% by weight before heat treatment.
, PH8.5, conductivity 4ms/cm or protein concentration 3% by weight, glucose concentration 2% by weight, PH
A soluble denatured egg white protein liquid can be obtained by heat treatment under conditions of 3.0 and conductivity of 1 ms/am.

When using ovalbumin solution as the egg white protein solution, the protein concentration is 5% by weight, pH 7,
5. Electrical conductivity 1mS/Cm1 or protein concentration 8
% by weight, glucose concentration 2% by weight, pH 8.0, conductivity 1 m s/cm or protein concentration 5
A soluble denatured egg white protein liquid can be obtained by heat treatment under the conditions of weight %, pH 3.0, and electrical conductivity of 1 ms/cm.

As described above, in order to adjust the soluble denatured egg white protein according to the present invention, the concentration of egg white protein before heat treatment, the PH1 conductivity, the proportion of ovalbumin, and the concentration of sugar and sugar alcohol are Any conditions that do not cause cloudy insolubilization at a temperature of 6 Or or higher may be used; these are not limited.

These soluble denatured egg white protein liquids are composed of structural units necessary for the gelation of egg white, that is, polymers of denatured egg white proteins, which are solubilized due to their mutual electrical repulsion. It becomes. If we weaken the electrical repulsion between the denatured egg white protein polymers,
These form a gel having a very uniform network structure, ie, a transparent egg white gel, without becoming cloudy and insolubilized.

In order to weaken the electrical repulsion between the polymers of soluble denatured egg white protein, the pH should be 6 or higher for soluble denatured egg white protein prepared on the alkaline side, and PH 4 for soluble denatured egg white protein prepared on the acidic side. Below, gelation may be performed by adjusting the protein concentration to 3% by weight or more and the neutral salt concentration to 0.1% by weight or more.

In order to increase the protein concentration to 3% by weight or more, the resulting soluble denatured egg white protein liquid may be freeze-dried or spray-dried to form a powder and then dissolved to the desired protein concentration. Alternatively, the obtained soluble denatured egg white protein liquid may be concentrated under reduced pressure or ultrafiltrated to achieve the desired protein concentration. Even if the protein concentration is 3% by weight or less, it does not form a transparent gel and remains a liquid or viscous liquid.

To adjust the pH, either a mineral acid or an organic acid may be used, but it is usually adjusted with hydrochloric acid or sodium hydroxide. When the pH is higher than 4 and lower than 6, the gel becomes cloudy.

As the neutral salt, sodium chloride, potassium chloride, calcium chloride, etc. can usually be used, but the salt is not limited thereto. The amount added is such that the protein concentration is 3% by weight or more and the pH is 6 or more or 4% by weight.
It is sufficient to add 0.1% by weight or more to the soluble denatured egg white protein liquid prepared as follows, and the amount may be adjusted as appropriate depending on the flavor of the food to be used, but it is usually preferable to add up to 10% by weight. .

In a soluble denatured egg white protein solution with a protein concentration of 3% by weight or more and a pH of 6 or more or 4 or less, when the amount of neutral salt added is 0.1 to 2.0% by weight, Addition of salt alone does not result in gelation, but a transparent egg white gel is formed by heating to 50C or higher.

When the amount of neutral salt added is more than 2% by weight, the soluble denatured egg white protein liquid will form a transparent egg white gel just by adding neutral salt, but it must be further heated at 50C or above. , resulting in a transparent egg white gel with stronger hardness.

Effects of the Invention The transparent egg white gel obtained by the present invention has elasticity unique to egg whites, similar to the usual cloudy egg white heated gel, and can be widely used in confectionery and side dishes. can.

In particular, since it gels by heating, it can provide a transparent gel in a warm state. This is something that has not been possible with any conventional gel. It is also highly nutritious,
The constituent proteins are heat-denatured, making them highly digestible, and can also be used as food for patients.

Examples Example 1. Raw egg white liquid LkQ & deionized water 2k (J) were added thereto, and after homogenization by stirring, the resulting insoluble matter was removed by centrifugation.

Add IN and sodium hydroxide solution to the yu serum and adjust the pH.
Adjusted by 104. The protein concentration at this time was 4% by weight.
, the electrical conductivity was 4 ms/cm.

This liquid was heat-treated at 65C for 30 minutes and then cooled to 20C. Then, by adding IN hydrochloric acid solution, the pH was adjusted to 7.
．． White powder 88.84i was prepared by spray drying.
got '.

One oy of this white powder was dissolved in 200 g of 1% by weight saline. The pH at that time was 7.3.

90 tl of this liquid? By heating for 3 minutes, a transparent egg white gel was obtained.

The protein concentration was determined from the absorbance of A2801+0++ (1% -). Also, E-7,2 was used.
The same applies to ON examples) Example 2゜ 2 kq of deionized water in which glucose was dissolved at a concentration of 3% by weight was added to 1 kg of raw egg white liquid, and after stirring to homogenize, the resulting insoluble matter was removed by centrifugation. . Moreover, IN sodium hydroxide solution was added to the clear liquid to adjust the pH to 9.0. At this time, the protein concentration was 4% by weight, and the electrical conductivity was 4 m s / cm.

This solution was heated at 80 C for 10 minutes and then cooled to 2 (1"). Thereafter, IN hydrochloric acid solution was added to adjust the pH to 7.5, and powder 145y was obtained by spray drying.

After dissolving 1.01 of this powder in deionized water]00FI, 3 g of potassium chloride was added and dissolved.

The protein concentration at this time was 6.0% by weight, and P
H was 7.2. By allowing this liquid to stand at room temperature, a transparent egg white gel was obtained.

Example 3 After adjusting the pH to 3.0 by adding IN hydrochloric acid solution to 1.0 kq of egg white liquid, the mixture was heated at 45 tll' for 30 minutes. The resulting white turbidity was removed by centrifugation, and the supernatant liquid was treated with an electrodialysis machine to reduce the electrical conductivity to 4. Dialysis was performed to m s/cm, and the resulting insoluble matter was removed by centrifugation.

When this supernatant was analyzed for its constituent proteins by SDS (sodium dodecyl sulfate) polyacrylamide gel electrophoresis, the band representing conalbumin had disappeared. Also, the protein concentration was 4% by weight.

IN sodium hydroxide solution was added to this liquid to adjust the pH to 8.5, and then heat treatment was performed at 75C for 5 minutes. After cooling to 20C, IN hydrochloric acid was added to adjust the pH to 7.5, followed by spray drying to obtain 420 g of white powder. 1.09 g of white powder was dissolved in 100 y of deionized water. The pH at that time was 6.8. Potassium chloride 1y was dissolved in this solution and heated at 50C for 5 minutes to obtain a transparent egg white gel.

Example 4 After adjusting the pH to 3.0 by adding IN hydrochloric acid solution to 10 kq of egg white liquid, the mixture was heated at 45C for 30 minutes. The resulting white cloudy aggregates were removed by centrifugation, and the resulting two-separate liquid was dialyzed using an electrodialysis machine to an electrical conductivity of 1'ms/cm. The resulting insoluble matter was removed by centrifugation. This supernatant was stored in SDS.
Analysis of its constituent proteins by (sodium dodecyl sulfate) polyacrylamide gel electrophoresis revealed that
The band indicated by conalbumin had disappeared. This liquid 1
200 g of 1 dextrin powder was added to 0 kq and dissolved, and then T'N hydrochloric acid solution was added to adjust the pH to 3.0.

The protein concentration at this time was 3% by weight. This liquid was heat-treated at 80C for 5 minutes and then cooled to 20C to obtain 10 kq of a soluble denatured egg white protein liquid. This liquid 1
1 g of potassium chloride salt was added to 0F/ and dissolved. At that time, PR was 3.5 and protein concentration was 3.0%.

This liquid was heated at 60C for 5 minutes to obtain a transparent egg white gel.

Example 5°P H7.5, conductivity Q, 5 m s / cm
100 g of an ovalbumin solution adjusted to a protein concentration of 5% by weight was heated at 8 Or for 30 minutes and then cooled to 20C to obtain 100 y of a soluble denatured egg white protein solution.

To 4 ml of this soluble denatured egg white protein solution, 1 ml of a 5% by weight sodium chloride solution was added and mixed. At that time, the pH was 7.4 and the protein concentration was 4.0% by weight. A transparent egg white gel was obtained by heating this solution at 80C for 10 minutes.

Also, this soluble 1Wj: of denatured egg white protein liquid 4m7!
To the mixture, 1 ml of 20% by weight sodium chloride solution was added and mixed. At that time, the pH was 7.0 and the protein concentration was 4% by weight. A transparent egg white gel was obtained by allowing this liquid to stand at room temperature.

Claims (1)

[Claims] ``A transparent gelatinized protein, characterized by gelling soluble denatured egg white protein at a protein concentration of 3% by weight or more, at a pH of 6 or more or 4 or less, and containing 0.1% or more of a neutral salt. "Production method of egg white gel"