JPH05244908A - New high melting point agalose type agar and its production - Google Patents

Abstract

PURPOSE:To provide the subject new agar capable of being thermally sterilized at a high temperature for a short time because of having a high gel dissolution temperature and useful as a high quality support material for electrophoresis because of containing only an extremely small amount of sulfate groups. CONSTITUTION:The objective agar comprises a methylated agalose of the formula in which 6-methyl-D-galactose bonded at the 3 position and 2-methyl-3,6- anhydro-L-galactose bonded at the 1,4-positions are alternately repeated or a combination of the methylated agalose with any other agalose pectin, the amount of the methylated agalose being 90-100wt.%. The elementary analysis values (measured values): C 46.5%. H 7.4%, O 45.7%; average mol.wt.: 650000 (by a gel filtration method); coloration reaction: positive to the coloring reaction of a neutral saccharide such as a phenol/sulfuric acid method and to the coloration reaction of a 3,6-anhydrogalactose compound such as a resorcinol/sulfuric acid method. The agar is obtained by extracting the Algae with hot water at 95-100 deg.C and subsequently extracting the extraction residue with 110-140 deg.C hot water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel high melting point agarose type agar having a high melting point and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Agar has long been known as a food, and is a substance composed mainly of polysaccharides extracted from the seaweed of the red algae. The chemical structure of agar consists mainly of agarose consisting of repeated α-1,3 linkages of agarobiose residues consisting of D-galactose which is β-1,4 linked to 3,6-anhydro-L-galactose, and agarobiose residues. It consists of agaropectin bound with sulfuric acid and pyruvate. Among them, it is also known that a part of D-galactose is methylated to 6-methyl-D-galactose, and the red alga Amixa (scientific name: Ceramium boydeni
In agarose extracted from i), D-galactose pair 6
There is an example in which the ratio of -methyl-D-galactose is 3: 2. On the other hand, 30% of 3,6-anhydro-L-galactose is methylated to give 2-methyl-
What became 3,6-anhydro-L-galactose is found in agarose extracted from the red alga Fujimatsumo (scientific name: Rhodomela larix). However, those in which the degree of methylation of constituent sugars exceeds 50% have not yet been known. Agar is extracted and produced from various red algae seaweeds,
The extraction temperature is usually 70 to 100 ° C, and rarely 100 to 1
Extraction may be performed in the temperature range of 20 ° C.

[0003]

When long-term storage of foods made by gelling agar, such as bean and tocorotene, at a temperature of about 80 ° C., the gel is not redissolved at present. Sterilization is performed. However, sterilization at low temperatures requires long heating to ensure a sterilizing effect. Further, agarose purified from agar is widely used as a support for electrophoresis as a means for studying proteins and nucleic acids, but it is desired that the structure has a small amount of sulfate groups as acidic groups. It is rare. Therefore, in the current production of agarose for electrophoresis, a treatment for removing the sulfate group is required. Therefore, the present invention can easily produce a novel high-melting-point agarose-type agar and its agar which can be sterilized by heating at high temperature for a short period of time and which has a very low content of sulfate groups and can be used also for electrophoresis. It is an object to provide a manufacturing method that can be performed.

[0004]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive research in order to solve the above problems. In the process, the red alga seaweed Ryukyugogonori was used in the first step to obtain 95
Hot water extraction at a temperature of ~ 100 ° C, 110-1 in the second stage
It was found that the two-stage hot water-extracted agar, which is extracted with hot water at a temperature of 40 ° C., has a high melting point. The novel high-melting-point agarose-type agar according to the present invention has 6-methyl-D-galactose bonded at the 1,3 position and 2-methyl-3,6-anhydro-L-galactose bonded at the 1,4 position. Methylated agarose which is alternately repeated, or mainly consisting of this methylated agarose and agaropectin other than the methylated agarose, wherein the proportion of the methylated agarose is in the range of 90 to 100% by weight based on the total weight. Characterize.

The agar protozoa used for the production of the novel high-melting point agarose type agar according to the present invention are seaweeds of the red algae, and among them, particularly preferred are Ryukyu Ogonori (scientific name: Gracilaria eucheumoides). Is. In order to produce the novel high-melting-point agarose agar according to the present invention using this agar algae, first, the raw material agar algae is washed with water at room temperature (10 to 30 ° C.) for 5 to 24 hours. By doing so, water-soluble salts are removed. Then 9
Agar I is obtained by extracting with hot water at 5 to 100 ° C, preferably 100 ° C, and dehydrating and drying the filtrate. The agar II obtained by extracting the extraction residue of the agar I with hot water at 110 to 140 ° C. and dehydrating and drying the filtrate is the novel high melting point agarose type agar according to the present invention. The novel high melting point agarose type agar II according to the present invention has an extremely low content of sulfate groups of 0.5 to 1.2%.

The physicochemical properties of the novel high melting point agarose type agar II according to the present invention obtained by the above method are as follows. (1) Elemental analysis value Measured value: C: 46.5%, H: 7.4%, O: 45.7% Theoretical value: C: 50.3%, H: 6.6%, O: 43.1% (2) Average molecular weight 650,000 (TSK-Gel Gel filtration with PW-5000-XL and pullulan as standard.) (3) Infrared absorption spectrum Shown in Figure 1. KBr tablet method (1 mg) using JASCO IRA-2
/ 200mgKBr). (4) Ultraviolet absorption spectrum Shown in FIG. Using Hitachi 220S type, concentration 0.6%, cell length 1
Measured under conditions of 0 mm and temperature of 60 ℃ (after melting at 121 ℃). (5) Color reaction Normal color reaction of neutral sugar (phenol sulfate method [M. Duboi
s et al., Analyt. Chem., 28, 350 (1956)], anthron sulfate method [R. Dreywood, Ind. Eng. Chem., 18, 499 (194
6)]) and color reaction to 3,6-anhydrogalactoses (resorcin sulfate method [W. Yaphe, Analyt.
Chem., 32, 1327-308 (1960)]). (6) Color of substance Colorless (7) ¹³ C-NMR spectrum Shown in FIG. Measured using a Varian XL-200 under the conditions of sample: 2% solution (D ₂ O), temperature: 80 ° C. (8) Structural formula is shown in FIG. 6-O-methyl-D- bonded at the 1,4 position
2-O- that binds to the galactopyranose residue at the 1,3 position
A structure in which methyl-3,6-anhydro-L-galactopyranose residues are alternately repeated. (9) Types of constituent components and component ratios are shown in Table 1. For the qualitative analysis of sugar, the hydrolyzate of this product was derivatized with alditol acetate and subjected to gas chromatography and mass spectrum. Quantitation was performed by adding glucose as an internal standard. The amount of sulfate group was determined by the rhodizonic acid method [T. T Terho and K. Hartiala, Anal. Bioche.
m., 41, 471 (1971)].

[0007]

[Table 1]

[0008]

EXAMPLES The present invention will be described in more detail with reference to examples. Example 1 1 kg of the red alga seaweed Ryukyugogonori was placed in a container of such a size that the algal bodies were sufficiently immersed therein, and washed overnight with continuous running of tap water. After draining the water, 5 l of hot water was added, and the mixture was heated and boiled, and heating was continued for 30 minutes. Filtration with gauze gave a filtrate IA. 5 l of hot water was added to the filtration residue, and the mixture was heated again and boiled, and heating was continued for 30 minutes. Filtration with gauze gave a filtrate IB. 5 l to the obtained filtration residue
Hot water was added and the mixture was placed in a high-pressure steam kettle and heated under pressure at 120 ° C. for 30 minutes. After the temperature had dropped to 100 ° C., it was taken out from the kettle and filtered with gauze to obtain a filtrate IIA. Add 5 liters of hot water to the filtration residue and put in a high-pressure steam kettle.
After heating under pressure at 20 ° C. for 30 minutes, it was taken out of the kettle and filtered through gauze to obtain a filtrate IIB. Next, filtrate IA
And the filtrate IB were combined to form a filtrate I, which was frozen, then thawed and dehydrated by a filter cloth. Freeze-dry this
g of agar I was obtained. Further, the filtrate IIA and the filtrate IIB were combined to form a filtrate II, which was frozen, thawed, dehydrated with a filter cloth, and freeze-dried to obtain 20 g of agar II.

1 g of agar II obtained through the above steps was added to 100
The mixture was suspended in water (ml), heated under pressure at 120 ° C. for 20 minutes to be dissolved, and then poured into a cylindrical mold to be cooled and gelled, and cut into a cylinder having a height of 17 mm. This was placed in a beaker containing hot water kept at 99 to 100 ° C. by hot water bath, and the change in its form was observed. As a comparative control, among commercially available high-melting-point agars, those having the highest gel melting point were melt-molded by the same method, and boiled in exactly the same conditions to observe the change in morphology. The results are shown in Table 2.

[0010]

[Table 2]

Example 2 With respect to the gel of the agar II listed in Example 1, the gel was extruded with a tokoroten thrust to form a tokoroten shape, and its change was observed under the same boil conditions. As a result, the agar II tocorotene gel retained its original shape until 60 minutes later.

Example 4 50 g of the agar II tocorotene-like gel listed in Example 2 was placed in a bowl, and 250 ml of boiling stock was poured therein to prepare a tocorotene-containing soup. At this time, Tokoroten did not melt or lose its shape, and a soup with a texture unique to agar was made.

[0013]

As described in detail above, the novel high-melting-point agarose-type agar according to the present invention has a higher melting temperature than the conventional agar, so that the agar such as tokoroten and honey bean is agar. When heat sterilization is performed for the purpose of preserving the food made by gelling for a long time, it is possible to heat at a higher temperature, which not only improves efficiency by shortening sterilization time, but also can be preserved by increasing sterilization efficacy. It has the effect of extending the period. In addition, foods made by gelling agar were usually chilled and eaten, but by using the novel high-melting point agarose type agar according to the present invention, the above-mentioned tocorotene is used as a soup, a pot dish, etc. It can be used for hot dishes. Furthermore, by utilizing the feature that the components of the novel high-melting-point agarose-type agar according to the present invention have extremely few sulfate groups, it can be used as a support for electrophoresis as a means for studying proteins and nucleic acids. The electrophoretic operation can be performed at a higher temperature than before. The industrial value of the present invention having such various advantages is very great.

[Brief description of drawings]

FIG. 1 is a diagram showing an infrared absorption spectrum of agar II produced in Example 1.

FIG. 2 is a diagram showing an ultraviolet absorption spectrum of agar II produced in Example 1.

FIG. 3 is a diagram showing a ¹³ C-NMR spectrum of agar II produced in Example 1.

FIG. 4 shows 6-O-methyl-D-galactopyranose residues bound at the 1,4 position of agar II prepared in Example 1 and 1,
2-O-methyl-3,6-anhydro-bonded at the 3-position
It is a structural formula of a structure in which L-galactopyranose residues are alternately repeated.

Claims (3)

[Claims] 1. A 6-methyl-D-galactose bond at the 1,3 position and a 2-methyl-3,6- bond at the 1,4 position.
Methylated agarose in which anhydro-L-galactose is alternately repeated, or mainly composed of the methylated agarose and agaropectin other than the methylated agarose, and the ratio of the methylated agarose is 90 to 100.
A novel high melting point agarose type agar characterized by being in the range of wt%. 2. A novel method for producing agarose-type agar having a high melting point, which comprises extracting agar algae with hot water at a temperature of 95 to 100 ° C. and then extracting the residue with hot water at a temperature of 110 to 140 ° C. .. 3. The method for producing a novel high-melting-point agarose agar according to claim 2, wherein the agar alga is the red alga Rhukyugoonori (scientific name: Gracilaria eucheumoides).