JP2000007705A - Wet-heat-treated xanthan gum and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the salt resistance and homogeneity of water dispersion of xanthan gum by heat treating xanthan gum while controlling the water content in a specified range to thereby control hydrogen bonding between saccharide chains and hydrogen bonding to water molecules. SOLUTION: Xanthan gum is improved by heating it at 80-150 deg.C for from 15 min to 50 hr in the presence of water vapor so that the water content becomes 1-60 wt.%. Dispersing in water at 10-100 deg.C before heating in a gas and then removing water so that the water content becomes 0-90 wt.% is effective and pref. When the heat treatment is done in the presence of oxygen, like in air, coloration is likely to occur; hence, the treatment is pref. done in an inert gas. When an aq. soln. of xanthan gum with a concn. of 0.5 wt.% is used, the viscosity (Brookfield type viscometer, 6 rpm, at 25 deg.C) of the aq. soln. after stirring at 25 deg.C for 1 hr is 2,000-25,000 mPa.s, and the viscosity of the aq. soln. of the same concn. after stirring at 80 deg.C for 1 hr is lower by 0-50% than that at 25 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a moist heat-treated xanthan gum and a method for producing the same. Such a modified xanthan gum is used as a thickener, a stabilizer, and an additive in the food field, cosmetics field, agrochemical field, pharmaceutical field, or petroleum field.

[0002]

2. Description of the Related Art Xanthan gum is obtained from the microorganism Xanthomonas campestris.
estris) is a kind of microbial polysaccharide produced from carbohydrates such as starch, glucose, and sucrose. The structure of xanthan gum mainly consists of D-glucose and D-glucose.
It consists of the sodium, potassium and calcium salts of mannose and D-glucuronic acid, and the main chain consists of the β-1,4 linkage of D-glucose. As a method of producing xanthan gum, after the fermentation process, heat treated to sterilize microorganisms, remove the alcohol produced by fermentation, drying,
A pulverizing method is known. It is known that xanthan gum is stable against salts, and that addition of salts increases the viscosity of an aqueous solution. Also, Japanese Patent Application Laid-Open No. 10-33
No. 125 discloses a method of drying xanthan gum powder by heating to improve the viscosity of xanthan gum.

[0003]

However, in the conventional heat drying method, the viscosity of the aqueous xanthan gum solution increases, but the salt resistance deteriorates, such as precipitation due to salt addition. In addition, the dispersibility in water makes it difficult to “makoko” and looks good, but it is microscopically non-uniform. There were problems such as formation of portions, uneven viscosity, and cloudiness.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve such a problem, and as a result, the salt resistance and water uniform dispersibility of xanthan gum have been found to be improved by the hydrogen bonds between the sugar chains of xanthan gum. It was found that controlling the hydrogen bond with water molecules could solve the problem. Specifically, they have found that xanthan gum heated while controlling the water content to a specific water range has excellent salt resistance and uniform water dissolution, and completed the present invention. That is, the present invention is a moist heat-treated xanthan gum characterized by being subjected to a heat treatment while controlling the water content of the xanthan gum, and a method for producing the same. Incidentally, the moist heat-treated xanthan gum of the present invention,
When an aqueous solution having a xanthan gum concentration of 0.5% by weight is used, 2000 to 25000 mPa · s (B-type viscometer 6
(25 ° C. rpm), but the salt resistance and water uniform dispersibility, which are difficult to quantify, are also improved by the present invention. The moist heat-treated xanthan gum of the present invention can be generally obtained by heating xanthan gum at 80 to 150 ° C. for 15 minutes to 50 hours while controlling the water content at 1 to 60% by weight. Before heating in a gas, it is more effective to disperse in water at 10 to 100 ° C. and remove the water so that the water content becomes 0 to 90% by weight, to improve the salt resistance and the uniform water dispersibility.
If the water temperature is lower than this range, the dispersion is not sufficient, and if the water temperature is higher, the conditions are pressurized, and it becomes difficult to carry out. The heating can be performed in a pressure system, a normal pressure system, or a reduced pressure system. Humidity 20-1
Although it can be carried out even in a gas of 00%, if carried out in the presence of oxygen such as in air, there is a possibility of coloring, so it is preferred to carry out in an inert gas.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. As described above, the moist heat-treated xanthan gum of the present invention is obtained by moist heat-treating xanthan gum. Further, it is preferable that after dispersing in water at 10 to 100 ° C., water is removed and the xanthan gum having a water content of 0 to 90% is subjected to wet heat treatment. Water at 10-100 ° C
It is preferably an aqueous alcohol solution of 20% or less.
By dispersing in water or an aqueous alcohol solution at 10 to 100 ° C. before heating, salt resistance and water uniform dispersibility are improved. The wet heat treatment is preferably performed in a gas having a humidity of 20 to 100% at 80 to 150 ° C. for 15 minutes to 50 hours. As the raw material xanthan gum used for producing the moist heat-treated xanthan gum, commercially available powdery or granular xanthan gum can be used. As such a raw material xanthan gum, in a method for producing xanthan gum that is separated from a culture obtained by liquid culturing Xanthomonas campestris with a lower alkanol using corn starch, glucose or the like as a carbon source, concentrated xanthan gum after fractional precipitation, Xanthan gum during the drying step can be used.

[0006] In order to produce moist heat-treated xanthan gum, such a raw material xanthan gum is heated in a gas containing steam. The humidity of the gas is 20 to 100%, preferably 20 to 80%, but the important point of the moist heat treatment is to control the ratio of xanthan gum and water during heating, and the moisture content during heating is 1 to water. It is desirable to heat at 60% by weight, preferably 5-40% by weight. Under these conditions, when heating is performed in a state of a small amount of water as in the drying step, the viscosity increases but the salt resistance and the water uniform dispersibility deteriorate. This is presumably because the water adsorbed on the xanthan gum is removed and the xanthan gum molecules form some relatively strong bonds on the surface of the xanthan gum particles. On the other hand, when the xanthan gum is heated in a state where there are appropriate water molecules, salt resistance and water uniform dispersibility are good while maintaining high viscosity. It is presumed that this is because a loose bond is uniformly formed between the hydroxyl group of the sugar chain and the adsorbed water and water of crystallization inside the xanthan gum particles. Heating at this time is 80
~ 150 ° C for 15 minutes ~ 50 hours, preferably 100 ~ 1
15 minutes to 6 hours at 50 ° C., more preferably 120 to 1 hour
15 minutes to 4 hours at 50 ° C. It is presumed that the salt resistance and water dispersibility of xanthan gum are related to the hydrogen bond between sugar chains of xanthan gum and the hydrogen bond with water molecules. Under these conditions, a short time on the high temperature side is desirable.
If the heating temperature is low, the wet heat treatment is not sufficient, and if heated for a long time, the possibility of coloring increases.

[0007] The above-mentioned heating is performed in a gas containing steam, but there is no particular limitation on gases other than steam.
Examples of the gas include air, nitrogen, oxygen, carbon dioxide, helium, argon, and the like.In general, there is a risk of coloring when performed in the presence of oxygen, and therefore, an inert gas that does not react with xanthan gum. It is desirable to carry out inside. The pressure at that time is not particularly limited.
Although the heat-moisture treated xanthan gum can be produced by the above method, a better heat-moisture treated xanthan gum is to disperse in water before performing the heat-moisture treatment. Specifically, xanthan gum is dispersed in water to remove water, and the xanthan gum having a moisture content of 0 to 90% by weight is subjected to wet heat treatment. Dispersion in water may be performed under the same conditions as those of ordinary xanthan gum in water, and is not particularly limited.
Disperse in water up to 100 ° C. with stirring for at least 10 minutes. The simplest method is to disperse by stirring at 50 to 80 ° C. for 20 minutes or more. Generally, a dispersion time of 3 hours by stirring is sufficient. The xanthan gum concentration is 0.1.
1 to 10% by weight is desirable from the viewpoint of operability. Further, an organic solvent or the like may be contained in the system of the aqueous solution. However, when the lower alcohol is contained in an amount of 20% by weight or more, xanthan gum is undesirably aggregated. The above-described method for treating xanthan gum can also be used in a production process for producing xanthan gum by fermentation.

[0008] The heat-moistened xanthan gum produced by the above method differs from conventional xanthan gum in its high viscosity. That is, when the moist heat-treated xanthan gum of the present invention is added to water so as to have a xanthan gum concentration of 0.5% by weight and stirred at 25 ° C. for 1 hour,
00 to 25000 mPa · s (B-type viscometer 6 rpm 25
° C). The stirring here is gentle stirring, for example, about 100 rpm in a propeller type stirrer. Dispersion conditions were rigorously compared to determine uniform dispersibility. That is, when added to water so that the xanthan gum concentration becomes 0.5% by weight and stirred at 80 ° C. for 1 hour (in the same manner as at 25 ° C.), 0 to 50% of the above viscosity is obtained.
It showed a low viscosity value. The conventional 0.5% by weight 25 ° C. aqueous dispersion of xanthan gum dried at 90 ° C. (heated for 48 hours) is 4200 mPa · s, but the viscosity of the 0.5% by weight 80 ° C. aqueous dispersion is reduced by 60% or more. And 12 more
Since the dried product at 5 ° C (heated for 2 hours) has poor water dispersibility and precipitates when dispersed in water at 25 ° C, the moist heat-treated xanthan gum of the present invention has a high viscosity and a high dispersibility. It is amazing. Xanthan gum obtained by wet heat treatment has a difference in physical properties as compared with conventional xanthan gum, but does not substantially change in molecular formula.

Although the moist heat-treated xanthan gum of the present invention can be used for the same applications as conventional xanthan gum,
At that time, the same thickening effect can be exhibited with a smaller dose than the conventional product. At that time, the thickening effect can be exhibited without impairing the salt resistance and the water uniform dispersibility of the aqueous solution. Such a moist heat-treated xanthan gum of the present invention can be used alone or in combination with other aqueous gelling agents, aqueous thickeners, salts, acids, emulsifiers, etc. to obtain stable gels, thickeners, and emulsions. . Therefore, the moist heat-treated xanthan gum of the present invention is used in the food field,
It is used as a thickener, a stabilizer, and an additive in the general industrial fields including the cosmetics field, agrochemical field, pharmaceutical field, petroleum field and paint field. EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, Comparative Examples, and Reference Examples, which are intended to exemplify the present invention and do not limit the present invention in any way.

[0010]

EXAMPLES Examples and comparative examples of the present invention will be described below. <Comparative Production Example 1 of Conventional Xanthan Gum> Xanthan gum powder was dried at 90 ° C, 105 ° C, and 125 ° C in the air. Samples were removed during the drying process and the water content was measured. Further, as a xanthan gum concentration of 0.5% by weight
And stirred at 25 ° C. for 1 hour or at 80 ° C. for 1 hour to measure the viscosity (B-type viscometer: 6 rpm, 25 ° C., rotor No. 2 or N).
o. 3). The aqueous dispersion at 25 ° C. and the aqueous dispersion at 80 ° C. were compared to compare the water uniform dispersibility. Further, the 25 ° C. dispersion solution was mixed with an equal amount of a 1% by weight sodium chloride solution, and the dispersibility was compared to examine salt resistance. Table 1 shows the results
3 are shown.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

[Table 3]

<Comparative Production Example 1 of Conventional Xanthan Gum>
After drying the xanthan gum powder in air at 125 ° C., water was sprayed on to increase the water content. Further, the mixture was added to water so as to have a xanthan gum concentration of 0.5% by weight, and stirred at 25 ° C. for 1 hour or at 80 ° C. for 1 hour to measure the viscosity (B-type viscometer: 6 rpm, 25 rpm).
° C, rotor No. 2 or No. 3). The aqueous dispersion at 25 ° C. and the aqueous dispersion at 80 ° C. were compared to compare the water uniform dispersibility. Further, the 25 ° C. dispersion solution was mixed with an equal amount of a 1% by weight sodium chloride solution, and the dispersibility was compared to examine salt resistance. Table 4 shows the results.

[0015]

[Table 4]

<Production Example 1 of Xanthan Gum Wet Heat Treatment> Xanthan gum powder was subjected to wet heat treatment at 90 ° C. while controlling moisture in a constant humidity and constant temperature phase. A sample was taken out during the wet heat treatment step, and the water content was measured. Further, the mixture was added to water so as to have a xanthan gum concentration of 0.5% by weight, and stirred at 25 ° C. for 1 hour or at 80 ° C. for 1 hour to measure the viscosity (B-type viscometer: 6 rpm, 25 rpm).
° C, rotor No. 2 or No. 3). The aqueous dispersion at 25 ° C. and the aqueous dispersion at 80 ° C. were compared to compare the water uniform dispersibility. Further, the 25 ° C. dispersion solution was mixed with an equal amount of a 1% by weight sodium chloride solution, and the dispersibility was compared to examine salt resistance. Table 5 shows the results.

[0017]

[Table 5]

<Production Example 2 of Wet Heat Treatment Xanthan Gum> Xanthan gum powder was subjected to wet heat treatment with steam at 105 ° C. in an autoclave. A sample was taken out during the wet heat treatment step, and the water content was measured. Further, the mixture was added to water so as to have a xanthan gum concentration of 0.5% by weight, and stirred at 25 ° C. for 1 hour or at 80 ° C. for 1 hour to measure the viscosity (B-type viscometer: 6 rpm, 25 ° C.). , Rotor N
o. 2 or No. 3). 25 ℃ dispersion aqueous solution and 80 ℃
The aqueous dispersion was compared to compare the water uniform dispersibility. Further, the 25 ° C. dispersion solution was mixed with an equal amount of a 1% by weight sodium chloride solution, and the dispersibility was compared to examine salt resistance. Table 6 shows the results.

[0019]

[Table 6]

<Production Example 3 of Wet Heat Treatment Xanthan Gum> The xanthan gum powder was subjected to wet heat treatment with steam at 125 ° C. in an autoclave. A sample was taken out during the wet heat treatment step, and the water content was measured. Further, the mixture was added to water so as to have a xanthan gum concentration of 0.5% by weight, and stirred at 25 ° C. for 1 hour or at 80 ° C. for 1 hour to measure the viscosity (B-type viscometer: 6 rpm, 25 ° C.). , Rotor N
o. 2 or No. 3 or No. 4). The aqueous dispersion at 25 ° C. and the aqueous dispersion at 80 ° C. were compared to compare the water uniform dispersibility. Further, the dispersion solution at 25 ° C. is
Salt resistance was examined by mixing with a sodium chloride solution and comparing the dispersibility. Table 7 shows the results.

[0021]

[Table 7]

<Production Example 4 of Wet Heat Treatment Xanthan Gum> Xanthan gum powder was dried at 90 ° C. for 48 hours and then heat treated with steam at 125 ° C. in an autoclave. A sample was taken out during the wet heat treatment step, and the water content was measured. Further, the mixture was added to water so as to have a xanthan gum concentration of 0.5% by weight, and stirred at 25 ° C. for 1 hour or at 80 ° C. for 1 hour to measure the viscosity (B-type viscometer: 6 rpm, 25 ° C.). , Rotor No. 2 or N
o. 3 or No. 4). 25 ℃ dispersion aqueous solution and 80 ℃
The aqueous dispersion was compared to compare the water uniform dispersibility. Further, the 25 ° C. dispersion solution was mixed with an equal amount of a 1% by weight sodium chloride solution, and the dispersibility was compared to examine salt resistance. Table 8 shows the results.

[0023]

[Table 8]

<Production Example 5 of Wet Heat Treatment Xanthan Gum> Xanthan gum powder was dispersed in water at 20 ° C. for 1 hour so as to be 5% by weight. After water was distilled off to obtain a powder, the mixture was subjected to wet heat treatment with steam at 125 ° C. or steam at 140 ° C. for 30 minutes in an autoclave. Xanthan gum was added to water so as to have a concentration of 0.5% by weight and stirred at 25 ° C. for 1 hour or at 80 ° C. for 1 hour to measure the viscosity (B-type viscometer: 6 rpm, 25 ° C., rotor) No.
4). The aqueous dispersion at 25 ° C. and the aqueous dispersion at 80 ° C. were compared to compare the water uniform dispersibility. Further, the 25 ° C. dispersion solution was mixed with an equal amount of a 1% by weight sodium chloride solution, and the dispersibility was compared to examine salt resistance. Table 9 shows the results.

[0025]

[Table 9]

[0026]

The heat-moistened xanthan gum of the present invention is a water-soluble thickener having high viscosity characteristics, and is excellent in salt resistance when formed into an aqueous solution and uniform dispersibility in water.

Claims (11)

[Claims] (1) Xanthan gum having a water content of 1 to 60% by weight.
Heat-moisture treated xanthan gum in the presence of water vapor. 2. When an aqueous solution having a xanthan gum concentration of 0.5% by weight is used, the viscosity of the aqueous solution after stirring at 25 ° C. for 1 hour (B-type viscometer at 6 rpm at 25 ° C.) is 2,000 to 250.
The moist heat-treated xanthan gum according to claim 1, wherein the pressure is 00 mPa · s. 3. When an aqueous solution having a xanthan gum concentration of 0.5% by weight is used, the viscosity of the aqueous solution after stirring at 25 ° C. for 1 hour (B-type viscometer at 6 rpm at 25 ° C.) is 2,000 to 250.
The viscosity of the aqueous solution after stirring at 80 ° C. for 1 hour at the same concentration at 00 mPa · s (B-type viscometer 6 rpm at 25 ° C.)
2. The heat-treated xanthan gum according to claim 1, wherein the xanthan gum has a viscosity value of 0 to 50% lower than that at 25 ° C. 4. The method for producing moist heat-treated xanthan gum according to claim 1, wherein xanthan gum having a water content of 0 to 90% by weight is subjected to wet heat treatment in the presence of steam. 5. The method according to claim 1, wherein after dispersing the xanthan gum in water at 10 to 100 ° C., the water is removed and the xanthan gum having a water content of 0 to 90% is subjected to a wet heat treatment in the presence of steam. 4. The method for producing a moist heat-treated xanthan gum according to any one of 1 to 3. 6. The method of claim 5, wherein the water at 10 to 100 ° C. is an aqueous alcohol solution having an alcohol content of 20% by weight or less. 7. The method according to claim 4, wherein the wet heat treatment is performed in a gas having a humidity of 20 to 100%.
3. The method for producing a moist heat-treated xanthan gum according to claim 1. 8. A wet heat treatment at 80 to 150 ° C. for 15 minutes to 50 hours.
8. The method according to claim 4, wherein the time is a time.
3. The method for producing a moist heat-treated xanthan gum according to claim 1. 9. A wet heat treatment at 100 to 150 ° C. for 15 minutes to 6 hours.
8. The method according to claim 4, wherein the time is a time.
3. The method for producing a moist heat-treated xanthan gum according to claim 1. 10. A wet heat treatment at 120 to 150 ° C. for 15 minutes or more.
The method for producing moist heat-treated xanthan gum according to any one of claims 4 to 7, wherein the treatment is performed for 4 hours. 11. The process for producing xanthan gum according to claim 4, wherein the heat treatment is carried out before or after the powdering process after fermentation of xanthan gum. Method.