JP2003259821A - Transparent gel and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a transparent gel which is prepared from gellan gum and a monovalent or bivalent metal salt and exhibits ≥90% transmittance and to provide a method for producing the same. <P>SOLUTION: A sol solution mixed with 0.1-1.0 wt.% of gellan gum as a gelling agent is prepared by heating. The sol solution is mixed with a monovalent or bivalent water-soluble salt and 0.2-2.0 wt.% of a sequestering agent, cooled and set to give the transparent gel. The obtained transparent gel has ≥90% transmittance. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel gel having excellent transparency and a method for producing the same.

[0002]

2. Description of the Related Art A transparent gel is disclosed in Japanese Patent Laid-Open No.
It is disclosed in Japanese Patent Publication No. 1-43966. This gel is
It is prepared by blending carrageenan and tamarind gum as a gelling agent. In order to prepare a gel having excellent transparency, it was necessary to use a highly transparent aqueous solution of carrageenan and tamarind gum, which are gelling agents used.

Further, in Japanese Patent Laid-Open No. 1-74239,
A transparent gel composition using gellan gum as a gelling agent is disclosed. By using gellan gum as a gelling agent, it becomes possible to lower the coagulation temperature,
A gel material having heat resistance can be prepared. It is disclosed that when the concentration of gellan gum exceeds 3.0% by weight, the transparency is lowered, but it is not intended to further improve the transparency of the gelled substance prepared with gellan gum.

[0004]

As described above, the gel prepared with gellan gum has transparency as compared with the case where other gelling agents such as gelatin and agar are used. The transparency may be impaired depending on the concentration or the salt concentration. The present invention is to improve the drawbacks of gels prepared with such conventional gellan gum, and is a colorless and transparent gel having a transmittance of 90% or more when viewed with the naked eye, and has a heat resistance of at least 90%. It was made for the purpose of obtaining a thermoreversible gel. That is, an object of the present invention is to provide a transparent gel having a transmittance of 90% or more and a method for producing the transparent gel.

[0005]

In view of the above situation, the inventors of the present invention have conducted earnest studies to provide a gel having excellent transparency. As a result, gellan gum was used alone as a gelling agent to prepare a sol solution, and calcium lactate and trisodium citrate, which is a sequestering agent, were added to the solution to cool it, and gelled, resulting in excellent transparency. It was found that such a gel can be obtained, and the present invention has been completed.

That is, the present invention contains 0.1 to 1.0% by weight of gellan gum as a gelling agent and has a transmittance of 90%.
% Of transparent gel. In the present invention, 0.1 to 1.0% by weight of gellan gum is blended as a gelling agent and heated to prepare a sol solution, and then a monovalent or divalent metal salt and a sequestering agent are added to the sol solution. Is a method of producing a transparent gel by adding 0.2 to 2.0% by weight of trisodium citrate, which is then cooled to gel.

The sequestering agent of the present invention refers to a compound having a ligand which exhibits a sequestering effect by binding with a metal ion to form a water-soluble suspension. As the sequestering agent, condensed phosphate, ethylenediaminetetraacetate (E
DTA), dihydroxyethylglycine, gluconic acid,
Examples include citric acid and salts thereof. Gellan gum in the present invention is used as a gelling agent. The amount of gellan gum used is 0.1 to 1.0 based on the total amount of gel.
Weight percent is preferred. Most preferred is 0.2-1.
It is 0% by weight. If it is less than 0.1% by weight, it has almost no gelation function, and if it exceeds 1.0% by weight, the transmittance is 9
It becomes difficult to obtain a transparent gel of 0% or more. The transmittance is measured by placing a sample in a glass cell having an optical path length of 10 mm and comparing the transmittance at 500 nm of visible light with distilled water.
0%). Further, in order to produce the transparent gel of the present invention, it is obtained by adding a monovalent or divalent metal salt and a sequestering agent to a sol solution obtained by heating gellan gum, and then cooling and gelling it. The metal ion sequestering agent may be mixed and heated to prepare a sol solution, to which a monovalent or divalent metal salt may be added, followed by cooling and gelation. Further, the transparent gel of the present invention having a transmittance of 90% or more generally gives a thermoreversible gel.

Since the gel of the present invention is excellent in transparency, it is suitable for gel foods requiring transparency, such as jelly. Since the gel of the present invention is thermoreversible, it is industrially easy to use. When used as a jelly, fruit juice, saccharides, acidulants, seasonings, colorants, flavors and the like may be added as necessary. As the fruit juice, apple, grapefruit, melon, peach, pear and the like can be used. As sugars, various sugars and liquid sugars can be used. Examples of these sugars include glucose, fructose,
Sucrose, lactose, maltose and the like can be used. As the liquid sugar, a concentrated sucrose solution, an invert sugar solution, a concentrated solution in which sugar and invert sugar are mixed, a concentrated sugar solution in which glucose is added, a concentrated sugar solution in which glucose and fructose are added, and the like can be used. As the acidulant, citric acid, malic acid, tartaric acid or the like can be used. The salt for gelling the gellan gum sol solution is monovalent or divalent.
Any valent water-soluble salt can be used.
In particular, salts which are harmless to food hygiene such as calcium lactate, calcium gluconate, calcium chloride and sodium chloride can be used. Although the amount used is not particularly limited, it is usually necessary to add 0.1% by weight or more for gelation. In the present invention, trisodium citrate is particularly preferable as the sequestering agent. Other sequestering agents can also be used.

A change in the transparency of the gel can be considered as a change in the structure of the gel. As the transparency of the gel changes, the properties of the gel, such as texture, change. The transparent gel of the present invention is characterized in that it has a slightly softer texture than gellan gum gel prepared without adding a sequestering agent.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, it is possible to easily obtain a transparent gel having a transmittance of 90% or more by gelling a jelly liquid filled in a cup. In order to obtain a transparent gel having a transmittance of 90% or more, gellan gum is 0.1 to 1.0% by weight as a gelling agent, and trisodium citrate is 0.2 to 2.0% by weight as a sequestering agent. % And 1
It can be obtained by dissolving a monovalent or divalent metal salt and then cooling it to gel.

[0011]

EXAMPLES Next, the present invention will be specifically described by showing Examples of the present invention. Gellan gum was dispersed in water in an amount of 0.1 to 2.0% by weight and heated to about 90 ° C. in a hot water bath to be dissolved. After confirming the dissolution of gellan gum, add trisodium citrate to 0.0
˜2.0 wt% and calcium lactate 0.3 wt% were added and well stirred to prepare a sol solution and cooled to obtain a gel. The results of the transmittance of the gel thus obtained are shown in Table 1.
It was shown to. The gellan gum concentration was adjusted to 0.
Tables 2 and 3 show the results of the dissolution time by heating of the thermoreversible gel prepared by cooling at 4, 0.6 and 0.8% by weight and the gel strength of the obtained gel. .

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

As shown in Table 1, the gel prepared by adding 0.5% by weight of trisodium citrate has the highest transparency, and the amount of trisodium citrate added reaches a peak of 0.5% by weight. In addition, the gel becomes slightly cloudy at less than 0.5% by weight and more than 0.5% by weight.

The gel transmittance, the dissolution time of the thermoreversible gel and the gel strength in the examples were measured by the following methods. Transmittance: Prepare a sol solution as a sample and set the optical path length to 10 mm
It was put into the glass cell of, cooled and gelled, and the gel temperature was set to 20 ° C. The transmittance (%) at 500 nm was measured using distilled water as a control (100%). Dissolution time of thermoreversible gel: A sol solution as a sample was prepared, put into a glass test tube at 4 g, and cooled to gel. A 0.5 g glass ball was placed on the gel and heated in a hot water bath to measure the time for the gel to melt and the glass ball to fall to the bottom of the test tube. Gel strength: A sol solution as a sample was prepared, 90 g was filled in a plastic cup, cooled and gelled, and the gel temperature was set to 20 ° C. Compressive fracture tester (Rheoner3
Gel strength was measured using 3005, manufactured by Sanden Co., Ltd.

Next, the effect of the concentration of trisodium citrate on the transparency of the gellan gum gel obtained in the present invention will be described with reference to transmission electron micrographs of the gellan gum gel structure. From the transmission electron micrograph of the gellan gum gel structure, the cloudy gel is characterized by the appearance of highly aggregated portions in the three-dimensional network structure. This aggregated portion scatters light and becomes a cause of loss of transparency.
The electron micrograph is the result of preparing a sample by the freeze replica method and observing it with a transmission electron microscope. Figure 1
FIG. 4 shows a transmission electron micrograph (scale is 200 nm) of the structure of gellan gum gel. By the same method as the example, 0.8% by weight gellan gum, 0.3% by weight calcium lactate and 0.0% trisodium citrate,
The structures of gels obtained by blending 0.1, 0.3, and 0.5% by weight, respectively, and cooling to gel are shown in FIGS.
It was shown to. The transmittances of 1 and 2 in the figure are 62.8 and 7 respectively.
The gel was cloudy at 5.3% and was a heat irreversible gel, and the gel strengths were 3590 and 7020 gf, respectively.
The transmittances of 3 and 4 in the figure were 91.7 and 94.7%, respectively, which were transparent, and were thermoreversible gels, and the gel strengths were 840 and 208 gf, respectively.

[0018]

According to the present invention, gellan gum as a gelling agent is dissolved in water and heated to prepare a sol solution, and then a monovalent or divalent metal salt and a sequestering agent, citric acid, are added to the sol solution. By adding sodium, cooling and gelling, a transparent gel having a transmittance of 90% or more can be obtained. The gel obtained by the present invention is colorless and transparent as if it were water, and is thermoreversible, so that it can be industrially used for gel foods. Further, the permeability and thermoreversibility of the gel obtained by the present invention are 0.2% by weight or more of trisodium citrate and 0.1 to 0.1% of gellan gum.
If it is 1.0% by weight, a gel having a transmittance of 90% or more and a thermoreversible property can be prepared. In addition, gels prepared by adding 0.5% by weight trisodium citrate have the highest permeabilities, with slightly less than 0.5% or more than 0.5% trisodium citrate by weight. A gel having a low gel transmittance is obtained. When the gellan gum concentration is 1.0% by weight or less, a gel having a high gel transmittance of 90% or more can be obtained.

[Brief description of drawings]

FIG. 1 is a transmission electron micrograph showing the structure of gellan gum gel without addition of trisodium citrate.

FIG. 2 is a transmission electron micrograph showing the structure of gellan gum gel containing 0.1% by weight of trisodium citrate.

FIG. 3 is a transmission electron micrograph showing the structure of gellan gum gel containing 0.3% by weight of trisodium citrate.

FIG. 4 is a transmission electron micrograph showing the structure of gellan gum gel containing 0.5% by weight of trisodium citrate.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Hata             7-17-37 Higashi Omiya Grand Oji, Omiya City, Saitama Prefecture             Unes 203 (72) Inventor Yasushige Sagara             Saitama Prefecture Iruma-gun Moroyama-cho Large Market 464-35 F-term (reference) 4B041 LC10 LD03 LH16 LK08 LP01                       LP16

Claims (3)

[Claims] 1. Gellan gum is 0.1 to 10 as a gelling agent.
1.0% by weight, 0.2 to 2.0% by weight of a sequestering agent and 0.1% by weight or more of a monovalent or divalent water-soluble salt, and a transmittance of 90 % Or more thermoreversible gel, a transparent gel. 2. The transparent gel according to claim 1, wherein the sequestering agent is trisodium citrate. 3. Gellan gum is used as a gelling agent in an amount of 0.2 to 10.
1.0 wt% was added and heated to prepare a sol solution, and then 0.1 to 2.0 wt% of a sequestering agent and 0.1 or more of a monovalent or divalent water-soluble salt were added to the sol solution. More than weight%
A method for producing a thermoreversible transparent gel having a transmittance of 90% or more, which comprises adding, cooling and gelling.