JPS63230038A - Prepared albumen forming hot clear solution and clear gel and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title albumen which keeping clear solution or forming clear gel even under heating in high salt concentration, by dialyzing albumen against water to lower ion strength and remove precipitate and heating the supernatant in the acidic region. CONSTITUTION:Albumen is dialyzed against water or diluted with water to lower the ion strength and the precipitate formed is removed. Then, the supernatant is, preferably after the protein concentration is adjusted, heated in an acidic region, e.g., at 2.5pH and 80 deg.C for 1hr, to give the objective albumen.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a modified egg white that remains transparent and solution-like or forms a transparent gel even when heated under high salt concentration, and a method for producing the same.

[Conventional technology]

Egg white is not only nutritionally and economically superior, but also has excellent functionality such as gel-forming ability, foaming ability, and emulsifying ability, and is widely used as a material for food processing.

However, since egg white forms a cloudy gel when heated, it cannot be used as a raw material for liquid foods in its original form, and heated egg white is accompanied by cloudiness, so it is not suitable for foods that are characterized by transparency or cloudiness as described above. Its use is restricted in food products. Conventionally, polysaccharides such as agar, alginic acid, and pectin, and animal proteins such as gelatin have been mainly used as transparent gel materials for confectionery, etc. There are aspects of sexuality that are not sufficient. Therefore, if transparency can be maintained even when heated, the uses of egg whites will be further expanded. In addition to food, it can also be used as a material for cosmetics and pharmaceuticals. Transparent egg white, not as an ingredient but as a food form, is specifically found in the Chinese dish of pepper. This is the result of alkaline treatment of egg whites.
It is known that this occurs. However, alkaline treatment of proteins is accompanied by a decrease in the nutritional value of the proteins, the production of anti-nutritional factors, and is not preferred as an actual food processing method. A method for preparing transparent egg white by subjecting ovalbumin to limited hydrolysis using a proteolytic enzyme has also been reported.

This method is a gentle processing method and is an excellent method, but
At present, it requires a large amount of expensive enzymes and is not economical.

Furthermore, there are reports of prepared egg whites that can be prepared such as transparent gels from preparations in which the conalbumin fraction is completely removed from egg whites, but this method does not allow for the specific removal of conalbumin, which accounts for more than 10% of egg whites. However, there remains a difficult problem in terms of what is needed. Furthermore, in any of these methods, when heating is performed in the presence of salt, a cloudy gel or a cloudy liquid is formed.

[Problem that the invention seeks to solve]

Therefore, the present inventors conducted intensive research to easily and inexpensively obtain modified egg white that can maintain a transparent liquid state or form a transparent gel even when heated under high salt concentration without reducing its nutritional value. The invention has been completed.

[Means for solving problems]

The present invention is a modified egg white obtained by dialyzing or diluting egg white against water to lower the ionic strength, removing the resulting precipitate, and then heating the supernatant in an acidic region, and a method for producing the same.

In the process of studying the heated egg white gel mechanism, the present inventor found that the turbidity and strength of heated egg white gels are strongly influenced by the pH 1 and ionic strength of the egg white before heating, and by adjusting the solvent conditions during heating, Clear solutions, clear gels, cloudy gels, and cloudy suspensions were arbitrarily prepared and found to be suitable for scales.

That is, fresh egg whites are adjusted to a pH of 1 to 12, heated at 80°C for 11 hours), and then heated to a pH of 11.
The above gives a brown transparent gel, but the pH
If it is less than 10, a cloudy gel is formed.

On the other hand, when a similar experiment was performed using egg whites dialyzed against water and the resulting precipitate was removed, the result was a colorless transparent gel in the pH 2 to 4 range, a cloudy suspension at around pH 6, and a cloudy suspension at pH 6.
Brown transparent gel in the 10-12 region, other p HT
A cloudy gel is formed in the J region.

Transparent gels are highly adhesive when prepared at pH 3.0 to 3.5;
It was found that the gel strength was extremely high when prepared using In addition, transparent gels are superior to cloudy gels in terms of water retention, which is an important gel characteristic.

Furthermore, the protein concentration was adjusted to 3% (W/V) or less,
When heated around pH 2.5, it maintains a transparent solution state. By performing the dialysis treatment and adjusting the pH to an acidic range in this manner, a heated transparent liquid and a transparent gel can be obtained.

Dialysis in the present invention is performed by exchanging 20 times or more of water as an external solution three or more times every few hours. As a result, the ionic strength is sufficiently reduced, and the electrical type conductivity of egg white is 1.
A similar result can be obtained by diluting with water instead of dialysis. That is, add 2 to 4 times the amount of water to the egg whites, stir carefully at room temperature for 1 hour without foaming, and then dissolve the resulting product. The precipitate is removed, the pH is adjusted to a range of 2.0 to 3.5, and a transparent gel is obtained by heating.

Next, when salt (NaCl) is added to the above dialyzed egg white and heated at similar pH values, a translucent gel forms at pH 2.5 to 3.0, and a cloudy suspension forms at around pH 6.
H12 forms a brown transparent gel, but all the others are white turbid gels. That is, the turbidity increases in all regions as salt is added, resulting in an opaque gel.

Therefore, the above-mentioned egg white was dialyzed against water and the precipitate was removed, and the protein content of the supernatant obtained by dialyzing the albumen was adjusted to 15 to 45 mg/- by adding water. The pH of the solution was adjusted to pH 2.5 with hydrochloric acid, citric acid, or other acid and heated (e.g.
0°C, 1 hour). The egg white solution obtained by cooling this solution remained transparent even when salt was added.

When salt was added to this transparent liquid and reheated, a transparent gel was formed. In other words, a heated egg white transparent gel was obtained even in the presence of salt. The gel thus prepared has low adhesion, high elasticity, and high strength.

Furthermore, analysis of the precipitate obtained by dialysis revealed that this precipitate was a complex of egg white proteins mainly consisting of lysozyme and ovomacroglobulin, and the protein composition ratio of the supernatant was almost the same as that of the original egg white. It has become clear that. That is, the supernatant mainly contains ovalbumin and conalbumin.

Example 1 After stirring fresh egg whites at room temperature for 1 hour without foaming,
Dialysis was performed against 50 times the volume of water. The dialysis fluid was replaced three times every 3 hours. The final dialysis was performed for 10 hours. The albumen after dialysis was centrifuged at 15.00 rpm (20,000xg) for 10 minutes to obtain an adjusted albumen as a supernatant. Dilute this adjusted egg white with water to give a protein concentration of 40 μ/d and a pH of 2.
, 5, and heated at 80° C. for 1 hour.

This liquid was a clear solution. Add salt (NaC1) to this solution.
Figure 1 shows the turbidity of the samples obtained by adding various concentrations of O to 400 mM and reheating at 80°C for 1 hour. Sample 1: Two-step heating). For comparison, 15. OOOrpm
Adjust the supernatant to pH 2, 5, 40 mg/@l,
Similarly, NaCl was added to each concentration, 80°C,
The turbidity of the sample obtained by heating for 1 hour is indicated by a white mark (specimen 2, one step heating). As is clear from this figure, N
Specimen heated before adding aC1 (specimen 1)
was shown to remain transparent up to about 300mM NaCl. Further, the hardness and adhesion of this sample were investigated and the results are shown in FIGS. 2 and 3. The hardness and adhesion of the gel were measured by placing 40 d of adjusted egg white in a 100-liter bottle with a lid, heating it at 80° C. for 1 hour, and then using the texture mode of Leonor 3305 (Yamagata, Tokyo). From this figure, it was found that Sample 1, that is, the gel prepared by two-step heating, had less adhesion and became a hard transparent gel when about 150 mM of NaCl was added. on the other hand,
After addition of NaCl, the gel (specimen 2) obtained by normal heating in one step was highly adhesive and was found to form a translucent or cloudy gel.

Example 2 Three times the amount of water was added to fresh egg whites, stirred at room temperature for 2 hours without foaming, and 3. After centrifugation at OOOrpm, 100ml, obtain the supernatant to obtain the adjusted albumen. HCI, or NaO
The pH of this adjusted egg white is adjusted from 1 to 12 using H, placed in a test tube for turbidity measurement with a diameter of 1 cm, and heated at 80° C. for 1 hour. After cooling under running water for 1 hour, apply N to each of these methods.
Add 150mM of aC1 and reheat at 80°C for 1 hour.
Cooling was performed in the same manner, and absorbance was measured. The result is the fourth
As shown in the figure. Even in these cases in the presence of salt, a transparent gel was formed in the pH range from 2 to 3.5. A cloudy white gel or suspension was formed at pH 4 to 9, and a colored transparent gel was formed at a pH higher than that.

〔Effect of the invention〕

The adjusted egg white of the present invention maintains a transparent solution state or forms a transparent gel even when heated in the presence of high salt concentration, and therefore can be widely used as a raw material for not only foods but also cosmetics, pharmaceuticals, and the like. In addition, this conditioned egg white is manufactured by simple processing of egg white, making it highly economical. Furthermore, the protein composition of the conditioned egg white itself is almost the same as that of the raw egg white, making it nutritionally superior. It is.

[Brief explanation of drawings]

Figure 1 shows the NaCl? in the adjusted egg white of the present invention? Figure 2 shows the relationship between ffi degree and turbidity, Figure 2 shows NaC1 concentration and hardness, Figure 3 shows NaCl concentration and adhesiveness, and Figure 4 shows the relationship between conditioned egg white (diluted in water) heated in the presence of salt. The relationship between pH and turbidity is shown.

Claims (2)

[Claims] (1) Adjusted egg white obtained by dialyzing or diluting egg white against water to lower the ionic strength, removing the resulting precipitate, and then heating the supernatant in an acidic region. (2) A preparation characterized by dialysis or dilution of the egg white against water, lowering the ionic strength and removing the resulting precipitate, and then heating the resulting supernatant under acidic conditions to adjust its protein concentration. How to make egg whites.