JP5505577B1 - Pectin aqueous solution - Google Patents

Abstract

Provided is an aqueous pectin solution that can be thickened even with an enteral nutrient having a sodium content of 180 mg / 100 mL or more and does not generate starch during storage. This aqueous pectin solution contains pectin having an esterification degree of 5 to 15% and a viscosity average molecular weight of 10,000 to 35,000. The calcium concentration of the aqueous pectin solution is 9 ppm or less, and the viscosity (25 ° C.) of the aqueous pectin solution is 1 to 30 mPa · s. The viscosity (at 25 ° C.) of a mixture of 100 mL of an aqueous pectin solution and 200 mL of an aqueous calcium / sodium solution of 0.019 mol / L calcium chloride and 0.020 mol / L sodium citrate is 700 to 10,000 mPa · s.

Description

  The present invention relates to an aqueous pectin solution useful as a thickener for enteral nutrients.

  The tube feeding method is performed in order to supply nutrition to those who cannot or cannot take food and beverages orally. There are two types of tube feeding methods: the nasogastric tube method in which enteral nutrient is administered through the tube from the nose to the stomach, and the gastrostomy in which the fistula is formed in the abdomen and the enteral nutrient is administered using a PEG tube. In both cases, enteral nutrients are liquids with viscosity that can be administered by tube, so enteral nutrients administered into the stomach may flow back into the esophagus and cause vomiting or rapidly enter the intestines. It causes problems such as causing diarrhea and damping syndrome. In particular, in the nasogastric tube method, the enteral nutrient is adjusted to have a low viscosity so that it passes through a thin tube, so that reflux into the esophagus, diarrhea, and dumping syndrome are problematic.

  Therefore, in order to prevent reflux of enteral nutrients, diarrhea, and dumping syndrome, thickeners such as low methoxyl pectin aqueous solution that thicken enteral nutrients in the stomach are used (Patent Documents 1 and 2). . Low methoxyl pectin has a degree of esterification (DE), which is a ratio of methyl esterified galacturonic acid constituting pectin, of less than 50%, and forms a gel in the presence of divalent metal ions such as calcium ions. .

WO2000 / 013529 pamphlet JP 2000-217544 A

  On the other hand, as a conventional enteral nutrient, one having a sodium content of 150 mg / 100 mL or less is often used. However, in order to prevent hyponatremia associated with long-term administration of enteral nutrient, Enteral nutrients having a larger amount, particularly enteral nutrients having a sodium concentration of 180 mg / 100 mL or more are also used.

  However, enteral nutrients with a high sodium content have a problem that they do not thicken with conventional low methoxyl pectin. On the other hand, it may be possible to further reduce the degree of esterification of low methoxyl pectin or increase the content of low methoxyl pectin. Starch is generated. On the other hand, increasing the content of low methoxyl pectin increases the viscosity of the aqueous solution of low methoxyl pectin, which increases the burden on medical personnel who inject using a syringe when passing through a thin tube such as a nasogastric tube It will be.

  Therefore, the present invention can increase the viscosity even with enteral nutrients containing sodium at a high concentration of 180 mg / 100 mL or more, and is suitable for tube administration in a thin tube. An object of the present invention is to provide an aqueous pectin solution that does not generate starch during storage.

  The present invention has found that the above-mentioned object can be achieved when the degree of esterification and molecular weight of pectin used in a pectin aqueous solution are within a specific range and the calcium concentration contained in the pectin aqueous solution is below a specific range. Completed.

  That is, the present invention relates to a pectin aqueous solution containing pectin having an esterification degree of 5 to 15% and a viscosity average molecular weight of 10,000 to 35000, wherein the calcium concentration of the pectin aqueous solution is 9 ppm or less, and the viscosity (25 ° C.) of the pectin aqueous solution is 1 to 30 mPa · s, and the viscosity (25 ° C.) of a mixture of 100 mL of the aqueous pectin solution and 200 mL of an aqueous calcium / sodium solution of 0.019 mol / L calcium chloride and 0.020 mol / L sodium citrate is 700 to 10,000 mPa Provide an aqueous pectin solution that becomes s.

  Moreover, this invention provides the thickener for tube administration which consists of the above-mentioned pectin aqueous solution.

  Furthermore, the present invention provides a pectin aqueous solution having a degree of esterification of 5 to 15%, diluted with water, and having a pectin content of 1 to 5% by mass as a method for producing the above-described aqueous pectin solution. In this case, there is provided a method of adjusting the viscosity (25 ° C.) of the aqueous pectin solution to 1 to 30 mPa · s by diluting the pectin in which the calcium concentration of the aqueous pectin solution is 9 ppm or less with water.

  According to the aqueous pectin solution of the present invention, not only conventional enteral nutrients with a sodium content of 150 mg / 100 mL or less, enteral nutrients with a higher sodium content, particularly enteral nutrition with a sodium content of 180 mg / 100 mL or more. The agent can also increase the viscosity, and prevent reflux of enteral nutrients administered into the stomach, diarrhea, and damping syndrome.

  In addition, according to the aqueous pectin solution of the present invention, since starch is unlikely to occur during storage, the user can use it with peace of mind.

Hereinafter, the present invention will be described in detail.
The aqueous pectin solution of the present invention contains low methoxyl pectin having an esterification degree (DE) of 5 to 15% as a main component. According to the aqueous pectin solution of the present invention, the degree of esterification of pectin is as low as 15% or less, and the calcium reactivity is high. Even if the enteral nutrient has a sodium content of 180 mg / 100 mL or more and a high sodium concentration, and the sodium content is lower than that, the enteral nutrient is By mixing with an aqueous pectin solution, the enteral nutrient can be thickened and reflux of enteral nutrients administered into the stomach, diarrhea, and dumping syndrome can be prevented. More specifically, for example, by adding 10 to 100 mL of the aqueous pectin solution of the present invention to 100 mL of enteral nutrient containing sodium at a high concentration of 180 to 220 mg / 100 mL, the viscosity of the mixed solution (25 ° C. ) (BH viscometer) can be 600 to 10000 mPa · s, preferably 800 to 3000 mPa · s.

  On the other hand, in the aqueous pectin solution of the present invention, if the degree of esterification of pectin is too low, it becomes a strong insoluble gel upon reaction with calcium ions, which is not preferable from the viewpoint of digestion and absorption. From the point of increasing the viscosity to an appropriate viscosity, the degree of esterification of the aqueous pectin solution is 5 to 15%, more preferably 6 to 13%. If the degree of esterification is higher than 15%, the reactivity of the aqueous pectin solution with calcium ions is low, and the enteral nutrient cannot be thickened sufficiently.

  The degree of esterification of the aqueous pectin solution can be measured by titration with an alkaline solution.

  Moreover, the pectin which the pectin aqueous solution of the present invention has as a main component has a viscosity average molecular weight of 10,000 to 35,000, preferably 12,000 to 27,000. Here, the viscosity average molecular weight is an average molecular weight calculated by an intrinsic viscosity method. If the viscosity average molecular weight of pectin is too large, a strong insoluble gel is generated by reaction with calcium ions, which is not preferable from the viewpoint of digestion and absorption. From the point of increasing the viscosity to an appropriate viscosity, the viscosity average molecular weight of the pectin aqueous solution is 35000 or less, preferably 27000 or less, more preferably 16000 or less. On the other hand, if the viscosity average molecular weight is too small, the reactivity with calcium ions in the aqueous pectin solution is low and the enteral nutrient cannot be sufficiently thickened. Therefore, the viscosity average molecular weight is 10,000 or more, preferably 12,000 or more. More preferably, it is 14000 or more. Moreover, by setting the viscosity average molecular weight of pectin within the above range, it becomes easy to adjust the viscosity of the aqueous pectin solution to 30 mPa · s (25 ° C.) or less suitable for tube administration.

  As described above, the pectin contained in the aqueous pectin solution of the present invention has an esterification degree of 5 to 15% and a viscosity average molecular weight of 10,000 to 35,000, preferably 12,000 to 27,000. When the calcium ion concentration in the mixed solution is 10 ppm or more, the viscosity of the mixed solution is 30 mPa · s (25 ° C.) or less suitable for tube administration. Thicken to 600 mPa · s or more. Since the calcium ion concentration of the enteral nutrient is at least 10 ppm or more, the enteral nutrient can be thickened by the aqueous pectin solution of the present invention.

  Such thickening action of the aqueous pectin solution of the present invention is achieved by stirring 100 mL of the aqueous pectin solution of the present invention and 200 mL of an aqueous calcium / sodium solution of 0.019 mol / L calcium chloride and 0.020 mol / L trisodium citrate for 30 seconds. When the viscosity (25 ° C.) 5 minutes after mixing the aqueous pectin solution and the aqueous calcium / sodium solution is measured at 20 rpm with a BH viscometer at a liquid temperature of 25 ° C., preferably 700 to 10,000 mPa · s, preferably By being 1400-8000 mPa * s, it distinguishes from the conventional pectin aqueous solution. In addition, the calcium content and sodium content in this calcium / sodium aqueous solution are the calcium content and sodium content of general enteral nutrients, and when pectin aqueous solution is mixed with enteral nutrients Used to examine thickening effect. When a conventional pectin aqueous solution is mixed with this calcium / sodium aqueous solution, the above viscosity range is not reached.

  Further, the aqueous pectin solution of the present invention has a viscosity (25 ° C.) of 30 mPa · s or less, preferably 10 mPa · s or less. If the viscosity of the aqueous pectin solution is too high, it becomes difficult to administer the aqueous pectin solution through a tube having an inner diameter of about 1 to 5 mm used for tube administration. The aqueous solution is suitable for tube administration and can be preferably used particularly by nasogastric tube method. In addition, the viscosity (25 degreeC) of the pectin aqueous solution of this invention shall be 1 mPa * s or more from the point which increases an enteral nutrient moderately.

  In the pectin aqueous solution of the present invention, the content of pectin can be appropriately adjusted according to the molecular weight of pectin so that the viscosity of the pectin aqueous solution is in the above range. For example, the viscosity average molecular weight of pectin is 10,000 to 35,000. In this case, the content may be 1 to 5% by mass. If the content of pectin is too small, the enteral nutrient cannot be thickened sufficiently. On the other hand, if it is too much, a strong gel is formed by the reaction with the enteral nutrient, so from the aspect of digestion and absorption. It is not preferable.

  The aqueous pectin solution of the present invention is also characterized by a low calcium concentration of 9 ppm or less. Since conventional low methoxyl pectin having a degree of esterification of about 10% contains 1000 ppm or more of calcium, even when low methoxyl pectin is diluted to a 1% by mass aqueous solution, the calcium concentration of the aqueous solution is 10 ppm or more. Become. When such a conventional low methoxyl pectin is made into an aqueous solution, starch is produced during storage for about 10 days at room temperature. For this reason, those who use it as a thickener for enteral nutrients are made to worry about quality. In addition, if the starch adheres to the tube, the tube may be blocked and the tube may be clogged. On the other hand, in the present invention, the generation of starch during storage of the aqueous pectin solution is suppressed by setting the calcium concentration in the aqueous pectin solution to 9 ppm or less, preferably 4.5 ppm or less.

  Moreover, the pH of the aqueous pectin solution of the present invention is preferably 2 to 8, more preferably 3.5 to 6. This is because, when the pH is too low or too high, the pectin may have a low molecular weight during storage, and the viscosity average molecular weight of the pectin may fall below the above-described preferable range.

  The aqueous pectin solution of the present invention can contain optional components such as a pH adjuster, vitamins, minerals, thickening polysaccharides, and stabilizers as necessary.

  As a method for producing an aqueous pectin solution of the present invention, for example, a commercially available low methoxyl pectin having a degree of esterification of 5 to 15% is used as a raw material pectin, and it is dissolved in pure water so that the pectin concentration is 1 to 5% by mass. An aqueous solution is prepared and its calcium concentration is measured. A general pectin has a high calcium concentration, and when a pectin aqueous solution having a pectin concentration of 1 to 5% by mass is prepared, the calcium concentration of the pectin aqueous solution is 10 ppm or more. In contrast, in the present invention, when the calcium concentration of the pectin aqueous solution having a pectin concentration of 1 to 5% by mass exceeds 9 ppm, the pectin concentration is similarly reduced to 1 to 5% by mass by subjecting the raw material pectin to a calcium reduction treatment. The calcium concentration in the prepared aqueous pectin solution is reduced to 9 ppm or less. On the other hand, when the calcium concentration is 9 ppm or less, the raw material pectin is selected as a pectin that can be used in the present invention without calcium reduction treatment.

  Pectin that has been subjected to calcium reduction treatment, or pectin selected as not requiring calcium reduction treatment is diluted with water and subjected to heat treatment or enzyme treatment as necessary to lower the molecular weight of pectin, resulting in a viscosity average molecular weight of 10,000. The aqueous pectin solution of the present invention having a viscosity of 1 to 30 mPa · s can be obtained by adjusting to ˜35000, preferably 12000 to 27000. Or you may perform a calcium reduction process, after diluting pectin with water so that pectin aqueous solution may become the above-mentioned viscosity. In addition, as water used here, a pure water or ion-exchange water is preferable.

  Here, examples of the calcium reduction treatment include a method of washing with a hydrous acidic solvent such as a nitric acid-containing isopropanol solution, a method using an ion exchange resin, and a method of filtering through an ultrafiltration membrane. Especially, the method using an ion exchange resin is preferable as a calcium reduction process from the point with few complexity of a manufacturing process.

  Moreover, as said heat processing, it is preferable to heat-press at a temperature of 100-145 degreeC and time 2-100 minutes, and to make low molecular weight the pectin aqueous solution to the viscosity average molecular weight 10000-35000. This heat and pressure treatment may be performed after the pectin aqueous solution is filled in the container.

  Further, in the production process of the aqueous pectin solution of the present invention, the pH is adjusted by adding an organic acid such as phosphoric acid, acetic acid and citric acid, an organic acid salt such as acetate and citrate, and a pH adjusting agent such as phosphate. It is preferable to adjust to 2-8.

  The aqueous pectin solution of the present invention is useful as a thickener for tube administration that thickens enteral nutrients in the stomach. Can also be used.

Hereinafter, the present invention will be specifically described based on examples.
Examples 1-10, Comparative Examples 1-9
As shown in Table 1, six types of commercially available pectin (A to G) having different esterification degrees, molecular weights, and calcium contents were prepared by different manufacturers, product names, or lots. In addition, a commercially available pectin solution (H) for thickening enteral nutrients was prepared (Comparative Example 9).

  In Example 1, pectin A having a degree of esterification of 7% was dissolved in pure water so as to be 3% by mass, 100 g of which was filled and sealed in a heat-resistant container, and heated and pressurized at a temperature of 110 ° C. for 30 minutes. The pectin aqueous solution was manufactured by processing.

  Moreover, the pectin aqueous solution of the density | concentration of Table 1 was prepared using the raw material pectin AG shown in Table 1, and the calcium reduction process or the molecular weight reduction process of pectin with respect to pectin aqueous solution was performed as shown in Table 1, and it implemented. The aqueous pectin solutions of Examples 2 to 10 and Comparative Examples 1 to 8 were produced.

  Although the exact content of pectin in the pectin solution of Comparative Example 9 is unknown, the dietary fiber content corresponding to the pectin content is 6 g per 100 g of pectin solution.

Evaluation About the pectin aqueous solution obtained in each Example and Comparative Example, (a) viscosity average molecular weight of pectin of the produced pectin aqueous solution, (b) viscosity of the produced pectin aqueous solution, (c) calcium concentration, (d) calcium sodium Reactivity with aqueous solution, (e) pH, (f) Starch generation state after storage, (g) Ease of use as a tube administration thickener, (h) Viscosity with enteral nutrients, ( i) Clinical trials were measured or evaluated as follows. The results are shown in Table 1.

(a) Viscosity average molecular weight of pectin The viscosity average molecular weight was measured by the intrinsic viscosity method as follows.
That is, a sample solution was prepared by diluting a pectin aqueous solution having a concentration shown in Table 1 with a 0.2 mol / L sodium chloride solution. Specifically, when the viscosity measured under conditions of BL type viscometer (manufactured by Toki Sangyo Co., Ltd.) rotor No. 10, 12 rpm, 25 ° C. is less than 20 mPa · s, 40 mL, 20 mL, 10 mL, 5 mL and 2.5 mL were accurately measured, and a 0.2 mol / L sodium chloride solution was added to each to make exactly 40 mL. When the viscosity measured with a BL-type viscometer is 20 mPa · s or more, accurately measure 8 mL, 4 mL, 2 mL, and 1 mL of pectin aqueous solution, and add 0.2 mol / L sodium chloride solution to each. A solution of 40 mL was used as a sample solution. About this sample solution and 0.2 mol / L sodium chloride solution (blank), 20.0 ± 0 according to the viscosity measurement method (first method capillary viscometer method) of the Japanese Pharmacopoeia (15th revision) general test method The specific viscosity was measured at 1 ° C. (formula A), and the reduced viscosity at each concentration was calculated (formula B). A graph was drawn with the reduced viscosity on the vertical axis and the pectin concentration (g / 100 mL) of the sample solution on the horizontal axis, and the intrinsic viscosity was determined from the intersection of the straight line connecting the points and the vertical axis. The intrinsic viscosity obtained here was substituted into Owens' formula (formula C) to calculate the average molecular weight (HS Owens, H.
Lotzkar, TH Sxhultz, WD Maclay J. Am. Chem. Soc. 1946, 68 (8) 1628-1632.).

(b) Viscosity of Pectin Aqueous Solution A pectin aqueous solution was measured with a BL type viscometer (manufactured by Toki Sangyo Co., Ltd.) at rotor No. 10, 12 rpm, and a liquid temperature of 25 ° C. Since the aqueous pectin solution of Comparative Example 8 had a viscosity of 50 mPa · s or more, it was measured at 6 rpm, and the pectin solution of Comparative Example 9 was measured at 0.6 rpm.

(c) Calcium concentration of aqueous pectin solution Measured by ICP emission spectroscopy.

(d) Reactivity of pectin aqueous solution with calcium / sodium aqueous solution Calcium chloride / dihydrate) 0.019 mol / L, trisodium citrate dihydrate 0.020 mol / L calcium / sodium aqueous solution was prepared. .
A total of 300 mL of 100 mL of pectin aqueous solution and 200 mL of calcium / sodium aqueous solution is weighed in a 300 mL beaker, stirred for 30 seconds, and mixed with pectin aqueous solution and calcium / sodium aqueous solution. Measured at 20 rpm and a liquid temperature of 25 ° C.

(e) pH of aqueous pectin solution
Measured with a METTLER TOLEDO Co., Ltd. Seven Easy S20.

(f) Generation of starch after storage After producing an aqueous pectin solution, it was stored at 60 ° C. for 4 weeks, and the presence or absence of starch generation was visually observed and evaluated according to the following criteria.
A: No starch is generated. O: A slight amount of starch is generated, but there is no problem. X: A large amount of starch is generated.

(g) Ease of use as a tube administration thickener Using a 50 mL syringe, a pectin aqueous solution is 8 Fr. The mixture was poured into a 90 cm-long nutrition tube (manufactured by JMS Co., Ltd.), and the ease of extrusion was evaluated according to the following criteria.
◎: Very easy to inject ○: Although there is a sense of resistance, it can be injected without problems ×: The syringe is hard and cannot be injected and cannot be injected

(h) Mixing test with enteral nutrients 100 mL of pectin aqueous solution was put into a 500 mL beaker, and two types of commercially available enteral nutrients with different sodium contents (Janev K-4S or Janef K-LEC, manufactured by QP Corporation) ) Add 400 mL and stir for 30 seconds. After mixing the aqueous pectin solution and enteral nutrient, the viscosity after 5 minutes is measured using a BH viscometer (manufactured by Tokyo Keiki Co., Ltd.), rotor No. 2, 20 rpm, liquid temperature 25 Measured at ° C. When the pectin solution of Comparative Example 9 was mixed with Janef K-4S, the rotor No. 3 of the BH type viscometer was used. When mixed with Janef K-LEC, the rotor of the BH type viscometer was used. No. 4 was used.

Here, the calcium content and sodium content of the enteral nutrient used are as follows.
Janef K-4S
Ca content: 60 mg / 100 mL
Na content: 180mg / 100mL
Janef K-LEC
Ca content: 60 mg / 100 mL
Na content: 80mg / 100mL

(i) Clinical study Enteral nutrient (calcium concentration 60 mg / 100 mL, sodium concentration 180 mg / 100 mL) has been administered to patients with symptoms of diarrhea and vomiting. About 100 mL of the pectin aqueous solution of the present invention was administered for 3 days per 400 mL of enteric nutrient, and the presence or absence of symptom improvement was examined and evaluated according to the following criteria.
○: Symptoms of vomiting and diarrhea improved.
×: Symptoms of vomiting and diarrhea are not improved

From Table 1, since the pectin aqueous solution of each Example of this invention has the esterification degree of pectin in the range of 5 to 15%, and the viscosity average molecular weight of pectin is in the range of 10,000 to 35000, calcium sodium It can be seen that the aqueous solution is sufficiently thickened. In these examples, the molecular weight is reduced by heat and pressure treatment (Examples 1 to 8 and 10) or by enzyme treatment (Example 9).
Furthermore, since the aqueous pectin solution of Example 1 was able to thicken both enteral nutrient (K-4S) rich in sodium and enteral nutrient (K-LEC) low in sodium, each example of the present invention It can be seen that enteral nutrients can be thickened regardless of whether the sodium content is high or low.

  Further, in these examples, the pectin used as a raw material is selected to have a low calcium content, so that the calcium concentration in the aqueous pectin solution is not reduced to 9 ppm or less (Example 1 -7, 9), wherein the calcium concentration in the aqueous pectin solution was reduced to 9 ppm or less by using an ion exchange resin (Examples 8 and 10). Starch is not generated. In particular, when the calcium concentration in the aqueous pectin solution is 4.5 ppm or less (Examples 1 to 5 and 7 to 9), it can be seen that no starch is generated.

  On the other hand, in Comparative Example 1 having a viscosity average molecular weight exceeding 35,000, a strong gel was formed by reaction with the calcium / sodium aqueous solution, and its viscosity was not measurable. Therefore, when the aqueous pectin solution of Comparative Example 1 is mixed with an enteral nutrient in the stomach, a strong gel is formed in the stomach, digestion and absorption are not sufficiently performed, and the nutrition of the enteral nutrient cannot be absorbed in a necessary amount. Is considered to occur.

  On the other hand, the aqueous pectin solution of Comparative Example 5 has low reactivity with calcium / sodium aqueous solution due to the degree of esterification exceeding 15%, and contains not only enteral nutrient (K-4S) with high sodium content but also sodium content. A small amount of enteral nutrient (K-LEC) could not be thickened sufficiently.

  Even in the aqueous pectin solutions of Comparative Examples 6, 7, and 8, pectin having an esterification degree exceeding 15% was used as a raw material. Among these, in Comparative Example 6, the viscosity average molecular weight after the molecular weight reduction treatment exceeded 35,000, but due to the high degree of esterification, the calcium / sodium aqueous solution could not be sufficiently thickened. In Comparative Example 7, since the molecular weight was not reduced by heat treatment, the calcium / sodium aqueous solution could be sufficiently thickened. However, when the viscosity of the pectin aqueous solution itself exceeded 30 mPa · s, it was applied to the feeding tube. Could not be injected. In Comparative Example 8, the pectin content in the aqueous pectin solution was increased to increase the reactivity with the calcium / sodium aqueous solution, but the viscosity of the aqueous pectin solution itself exceeded 30 mPa · s, and this was applied to the feeding tube. Could not be injected.

  On the other hand, in Comparative Example 2, the same pectin as in Example 1 was used as a raw material, but by increasing its content, the viscosity of the pectin aqueous solution itself exceeded 30 mPa · s, which could be injected into the feeding tube. There wasn't.

  In Comparative Examples 2 to 4 and 6 to 9 where the calcium concentration in the aqueous solution exceeded 9 ppm, starch was generated after storage. Of these, Comparative Examples 2 and 3 were made from the same pectin as in Example 1, but in Comparative Example 2, the calcium concentration in the pectin aqueous solution increased due to the increased content of the raw pectin, In Comparative Example 3, since the tap water was used as the dilution water, the calcium concentration in the aqueous pectin solution was increased by the calcium contained in the tap water, and it was considered that starch was generated respectively. It turns out that the calcium concentration of the commercially available enteral nutrient thickening pectin liquid of the comparative example 9 is 10 times or more higher than Examples 1-10.

The aqueous pectin solution of the present invention can be used as a thickener for enteral nutrients, a trotomy agent as a swallowing supplement, or a semi-solidifying agent.

Claims (11)

  A pectin aqueous solution containing pectin having an esterification degree of 5 to 15% and a viscosity average molecular weight of 10,000 to 35,000, wherein the calcium concentration of the pectin aqueous solution is 9 ppm or less, and the viscosity (25 ° C.) of the pectin aqueous solution is 1 to 30 mPa · s. A pectin aqueous solution in which the viscosity (25 ° C.) of a mixture of 100 mL of the aqueous pectin solution and 200 mL of an aqueous calcium / sodium solution of 0.019 mol / L of calcium chloride and 0.020 mol / L of sodium citrate is 700 to 10,000 mPa · s. .   The pectin aqueous solution according to claim 1, wherein the content of pectin is 1 to 5% by mass.   The aqueous pectin solution according to claim 1 or 2, having a pH of 2 to 8.   The pectin aqueous solution according to any one of claims 1 to 3, wherein a calcium reduction treatment is performed.   The thickener for tube administration which consists of the pectin aqueous solution in any one of Claims 1-4.   The thickener for tube administration according to claim 5, which is used for thickening an enteral nutrient in the stomach.   Pectin having a degree of esterification of 5 to 15%, and when the pectin is diluted with water to prepare a pectin aqueous solution having a pectin content of 1 to 5% by mass, the calcium concentration of the pectin aqueous solution is 9 ppm or less. The method for producing an aqueous pectin solution according to any one of claims 1 to 4, wherein the pectin solution is diluted with water to adjust the viscosity (25 ° C) of the aqueous pectin solution to 1 to 30 mPa · s.   When the pectin has an esterification degree of 5 to 15% and the pectin is diluted with water to prepare a pectin aqueous solution having a pectin content of 1 to 5% by mass, when the calcium concentration of the pectin aqueous solution exceeds 9 ppm, The method for producing an aqueous pectin solution according to claim 7, wherein the pectin is subjected to a calcium reduction treatment, and the pectin aqueous solution prepared in the same manner has a calcium concentration of 9 ppm or less as a raw material pectin.   The method for producing an aqueous pectin solution according to claim 7 or 8, wherein the molecular weight reduction treatment is performed so that the viscosity average molecular weight is 10,000 to 35,000.   The method for producing a pectin aqueous solution according to claim 9, wherein the molecular weight reduction treatment is performed at a temperature of 100 to 145 ° C. for 2 to 100 minutes. The manufacturing method of the pectin aqueous solution in any one of Claims 7-10 adjusted to pH 2-8.