JPH0688908B2 - How to remove the bitterness and astringency of Gymnema sylvestre leaf extract - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for removing bitterness and astringency of Gymnema sylvestre leaf extract.

Technical background of the invention and its problems Gymnema sylvestre R Br.
Are native to India and belong to the family Potato, and grow in well-drained areas such as hills and mountains.

Gymnematic acid, which is also one of the glycosides contained in such Gymnema sylvestre leaf extract, has a unique sweetness suppressing effect that significantly suppresses only the taste of sweetness among human four tastes, namely salty taste, sourness, bitterness and sweetness. It has been used as a therapeutic drug for diabetes in India since ancient times. Further, in recent years, it has been confirmed that glycosides such as Gymnema acid contained in Gymnema sylvestre leaves have an inhibitory effect on elevation of blood glucose level.

This Gymnema sylvestre leaf extract contains various compounds such as other glycosides in addition to gymnematic acid, and it is extremely difficult to isolate gymnema acid alone from this Gymnema sylvestre leaf extract. Is. For this reason, the whole extract was usually ingested from Gymnema sylvestre leaf extract containing Gymnema acid without isolation.

However, Gymnema sylvestre leaf extract has a very strong bitterness or astringency, which is a major obstacle to oral ingestion. Therefore, if bitterness or astringency can be removed from Gymnema sylvestre leaf extract, its practical value is extremely high.

OBJECT OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and to improve the bitterness or astringency of Gymnema sylvestre leaf extract containing useful glycosides such as Gymnema acid. It is intended to provide a method for removal.

SUMMARY OF THE INVENTION The method of removing the bitterness / astringency of Gymnema sylvestre leaf extract according to the present invention is a Gymnema sylvestre leaf extract containing less than 5 times the solid weight of the extract, preferably 0.1 times or more and 5 times the amount. It is characterized in that the Bacillus stearothermophilus-derived α-glucosyltransferase is allowed to act in the presence of less than a starchy substance to α-glucosylate the glycosides contained in the extract.

In the method of removing the bitterness / astringency of Gymnema sylvestre leaf extract according to the present invention, in Gymnema sylvestre leaf extract,
The α-glucosyltransferase derived from Bacillus stearothermophilus is allowed to act in the presence of less than 5 times the solid weight of the extract, preferably 0.1 times or more but less than 5 times the amount of starch, and Since the glycosides contained are α-glucosylated, the bitterness / astringency component contained in the extract is also α-glucosylated to eliminate the bitterness / astringency, and the intake of the extract is significantly facilitated. Become.

DETAILED DESCRIPTION OF THE INVENTION The method for removing the bitterness / astringency of Gymnema sylvestre leaf extract according to the present invention will be specifically described below.

In the present invention, Gymnema sylvestre leaf extract is treated to remove bitterness and astringency, but Gymnema sylvestre leaf extract is usually dried Gymnema sylvestre leaf,
It can be obtained by directly or crushing the obtained dried leaves into a powder and extracting with warm water. An organic solvent such as ethanol can be used for the extraction.

The Gymnema sylvestre leaf extract thus obtained may be used as it is, but in some cases, the extract may be subjected to treatments such as filtration, concentration, acid precipitation, decolorization and desalting. . Further, in some cases, a Gymnema sylvestre leaf extract prepared by extracting a solid component from the extract as described above and dissolving it in a solvent such as water can be used. It is also possible to use Gymnema sylvestre leaf extract obtained by mixing the above-mentioned Gymnema sylvestre leaf extract with a medicinal herb extract containing other active ingredients.

The solid content concentration in such Gymnema sylvestre leaf extract is preferably about 0.1 to 25% by weight.

In the present invention, the above-mentioned Gymnema sylvestre leaf extract is used in an amount of less than 5 times the solid weight of the extract, preferably 0.
Α-glucosyltransferase from Bacillus stearothermophilus is allowed to act in the presence of starch in an amount of 1-fold or more and less than 5-fold to convert the glycosides contained in the extract into α-glucosyltransferase.
Glucosylate. In order to make α-glucosyltransferase act on Gymnema sylvestre leaf extract in the presence of the above-mentioned amount of starch, the starch and the above α-glucosyltransferase are added to the extract, and the pH of the system is adjusted. 3-10 preferably
Keep at 5.5-6.5, the system temperature is 20-90 ℃, preferably 55-70
It may be kept at ℃.

The starch used in the present invention may be any one that is a substrate of α-glucosyltransferase derived from Bacillus stearothermophilus, which is one type of α-glucosyltransferase, and specifically, amylose , Amylopectin,
In addition to starch and the like, cyclodextrin, starch liquefaction having a DE of about 1 to 50, starch partial hydrolyzate such as saccharified starch and the like can be used.

Such starch is preferably added to the extract in an amount less than 5 times, preferably 0.1 times or more and less than 5 times the solid weight of Gymnema sylvestre leaf extract.

In the present invention, as the α-glucosyltransferase, among the enzymes capable of α-glucosylating glycosides contained in Gymnema sylvestre leaf extract in the presence of starch, Bacillus stearoa, which is a bacterium of the genus Bacillus An α-glucosyltransferase (other name: cyclomaltodextrin glucanotransferase) derived from Thermophilus is used. Α-derived from Bacillus stearothermophilus
Glucosyltransferase not only has high thermostability but also high transfer efficiency, and can easily remove the bitterness and astringency of Gymnema sylvestre leaf extract by using a small amount of starch.

This α-glucosyltransferase does not necessarily have to be purified and used, and a crudely purified enzyme is usually sufficient.

This α-glucosyltransferase is processed by Gymnema
100 to 50, per 100 g of starch added to sylvestre leaf extract,
It is preferably added to the extract in an amount of 000 units, preferably 1,000 to 20,000 units.

When the Gymnema sylvestre leaf extract is treated as described above, the bitterness and astringency of the extract are removed. this is,
The bitterness / astringency component contained in the extract is α-glucosyltransferase in the presence of starch,
-This is probably because it is glycosylated to become an α-glucosyl glycoside. Moreover, in the present invention, Gymnema
It is not necessary to α-glucosylate all glycosides such as gymnematic acid contained in the Sylvester leaf extract, and if a part of the glycosides contained in the extract is α-glucosylated,
The bitterness and astringency of the extract are removed. This suggests that the bitterness / astringency of the extract may be caused not only by a large amount of gymnematic acid contained in the extract but also by an unknown glycoside.

The Gymnema sylvestre leaf extract which has been treated in this way and from which the bitterness / astringency has been removed can be directly used for eating and drinking, but usually after heating the extract to inactivate the α-glucosyltransferase, It can also be served for eating and drinking. In some cases, the extract can be concentrated or dried and powdered for use in food and drink. Further, in some cases, the extract can be purified by using a decolorizing agent, an ion exchange resin, an adsorption resin or the like and then used for eating and drinking.

It is also possible to separate and remove unreacted substances, produce a purified product which is mostly occupied by α-glucosylated products, and use it for eating and drinking.

Effects of the Invention In the method for removing the bitterness / astringency of Gymnema sylvestre leaf extract according to the present invention, α-glucosyl transfer derived from Bacillus stearothermophilus is obtained in the presence of a specific amount of starchy substance in Gymnema sylvestre leaf extract. An enzyme (also known as cyclomaltodextrin glucanotransferase) acts to α-glucosylate the glycosides contained in the extract, so that the bitter and astringent components contained in the extract are also α-glucosyl. As a result, the bitterness and astringency disappear and the intake of the extract becomes extremely easy.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 To 375 g of dried powder of Gymnema sylvestre leaves, 6.0 liters of warm water was added, and heated at 80 ° C. for 90 minutes to extract the leaf components of Gymnema sylvestre, then diatomaceous earth was added, and solid-liquid separation was performed by vacuum filtration. And purified. The cake produced in this filtration step is thoroughly washed with warm water, and the obtained washing liquid and filtrate are combined.
9.0 liter Gymnema sylvestre leaf extract (undiluted solution)
Was prepared. The weight of dry matter contained in this extract is 8
It was 6.4 g.

To 3.0 liters of Gymnema sylvestre leaf extract prepared as described above, 50 g of dextrin of DE-6 was added and dissolved, and then 1N NaOH was added to the system to adjust the pH to 6.0.
Adjusted to. Then, 1,400 units of Bacillus stearothermophilus α-glucosyltransferase (Hayashibara Biochemical Laboratories) were added to the pH-adjusted solution containing the extract, and the mixture was kept at 60 ° C and reacted for 72 hours. Then, the enzyme was inactivated by heating at 95 ° C to obtain a treated Gymnema sylvestre leaf extract.

Test Example Solution A, solution B and solution C as described below were prepared.

(Solution A) A solution prepared by diluting the treated Gymnema sylvestre leaf extract obtained in Example 1 with pure water by a factor of 2.

(Solution B) As a control, 3.0 liter of the stock solution of Example 1 was added with DE
A solution in which 50 g of dextrin of -6 was added and dissolved, 1N NaOH was added to the system to adjust the pH to 6.0, and then the solution was diluted twice with pure water.

(C liquid) 50g of dextrin of DE-6 in 3.0l of pure water
Was added and dissolved, then 10 mmol of CaCl ₂ was added, and 1N hydrochloric acid was added to the system to adjust the pH to 6.0,
Next, Bacillus stearothermophilus-derived α-glucosyltransferase (Hayashibara Biochemical Laboratories) 1,400
After adding the unit and maintaining it at 60 ℃ and reacting for 30 hours, 95 ℃
A solution obtained by heating the above to inactivate the enzyme and mixing with 3 liters of the stock solution of Example 1.

Liquid A and control liquids B and C were subjected to a taste comparison test at room temperature of 27 ° C. by 10 panelists. As a result of the test, 10 persons (all members) judged that the taste of the solution A was the best among the solutions A, B and C. Also, B
4 out of 10 people judged that the taste of the liquid was the worst,
The remaining 6 persons judged that the liquid C had the worst taste. The results are shown in Table 1.

The liquids B and C, which were the controls, all had remarkable bitterness and astringency, but the liquid A had almost no bitterness and astringency.
To confirm whether or not cyclodextrin was produced in the solution A, 10 ml of trichloroethylene was added to 10 ml of the solution A, and the mixture was shaken well but did not become cloudy. Therefore, it is considered that cyclodextrin was hardly produced. To be

Reference Example (Solution D) Glucoamylase 5 was added to 500 ml of Solution A used in the test example.
After adding 000 GUN and reacting at 55 ° C. for 24 hours, the mixture was heated to 95 ° C. to inactivate the enzyme to obtain a liquid D.

When the taste quality of the obtained liquid D was examined, it had almost the same bitterness and astringency as those of B and C.

This means that the α-glucosylated glycoside in solution A was decomposed by glucoamylase and returned to the original glycoside, resulting in bitterness and astringency.

Example 2 A Gymnema sylvestre leaf extract was prepared from Gymnema sylvestre leaves by the same method as in Example 1, and then freeze-dried to obtain an extracted powder product.

(F liquid) 10 g of this extracted powder product and 40 g of DE-6 dextrin
Is dissolved in 60 ml of water and the pH is adjusted to 6.0.
600 units of α-glucosyltransferase derived from stearothermophilus was added, and the mixture was maintained at 68 ° C and reacted for 48 hours. This solution was heated to 95 ° C. to deactivate the enzyme, and this was designated as solution F.

When the taste quality of the obtained liquid F was examined, bitterness and astringency almost disappeared. Further, as in Example 1, it was confirmed whether or not cyclodextrin was contained in the F liquid by using trichlorethylene, and as a result, white turbidity was not observed. Therefore, it is considered that the cyclodextrin was hardly generated in the F liquid. To be

Example 3 To 500 g of dried powder of Gymnema sylvestre leaf, 8.0 liter of 40% ethyl alcohol was added and heated at 60 ° C. for 120 minutes to extract a Gymnema sylvester leaf extract component. Then, diatomaceous earth was added to the obtained extract, solid-liquid separation was performed by vacuum filtration, and the filtrate (i) was separated. The cake generated in this filtration step was thoroughly washed with 40% ethyl alcohol, the obtained washing liquid (ii) was combined with the above filtrate (i), alcohol was removed and concentrated under vacuum, and then freeze-dried. Then, it was pulverized to obtain 160 g of Gymnema sylvestre leaf extract powder.

Next, this Gymnema sylvestre leaf extract powder 13.3g
And 26.6 g of DE-8 dextrin (twice the amount of Gymnema sylvestre leaf extract powder, which is the solid content) were dissolved in water, and 1N NaOH was added to the resulting aqueous solution to adjust the pH to 6.0. After adjustment, 100 g of an aqueous dextrin solution of Gymnema sylvestre leaf extract containing a total of 40% concentration of Gymnema sylvestre leaf extract and dextrin was prepared.

Bacillus stearothermophilus α-glucosyltransferase (manufactured by Hayashibara Biochemical Research Institute) 400 units (15 units / dextrin g) were added to the dextrin aqueous solution of Gymnema sylvestre leaf extract, and the mixture was heated at 68 ° C for 40 hours. After the reaction, the enzyme was inactivated by heating to 95 ° C.

After deactivating the enzyme in the reaction solution, it was freeze-dried and then pulverized to obtain powder sample A-1.

Comparative Example 1 In Example 3, in place of the α-glucosyltransferase derived from Bacillus stearothermophilus, α-glucosyltransferase derived from Bacillus macerans (trade name: Contizyme, manufactured by Amano Pharmaceutical Co., Ltd.) 400 units ( 15 units / dextrin g) was added and treated in the same manner as in Example 3 except that the reaction was carried out at 55 ° C. for 40 hours to obtain a powder sample A-2.

Comparative Example 2 In Comparative Example 1, in the same manner as in Comparative Example 1 except that the Bacillus megaterium-derived α-glucosyltransferase, which was prepared as described below, was used instead of the Bacillus macerans-derived α-glucosyltransferase. Powder sample A-3
Got

[Preparation of Bacillus megaterium-Derived α-Glucosyltransferase] According to the method described in JP-B-57-18779, Bacillus
Megaterium FERM-P No. 935 with soluble starch 2W / V
%, Ammonium nitrate 1W / V%, dipotassium phosphate 0.1W / V
%, Magnesium sulfate heptahydrate 0.05 W / V%, corn stapler 0.5 W / V%, calcium carbonate 1 W / V%, inoculated into 5 liters of sterilized liquid medium, and aerobically stirred culture at 28 ° C for 3 days did. After the completion of the culture, 0.7 times the saturated amount of ammonium sulfate was added to the supernatant obtained by centrifugation, and the mixture was further centrifuged to collect the precipitate (α-glucosyltransferase derived from Bacillus megaterium).

Comparative Example 3 A powder sample A-BL was obtained in the same manner as in Example 3, except that 100 g of the dextrin solution of Gymnema sylvestre leaf extract was freeze-dried as it was without adding an enzyme.

Example 4 In Example 3, Gymnema sylvestre leaf extract powder 7.
3 g and dextrin 32.7 g (4.5 times the amount of Gymnema sylvestre leaf extract powder) were used, and 490 units of α-glucosyl transferase from Bacillus stearothermophilus (1
Powder sample B-1 was obtained in the same manner as in Example 3 except that 5 units / dextrin g) was used.

Comparative Example 4 In Example 4, 15 units of α-glucosyltransferase (trade name: Contizyme, manufactured by Amano Pharmaceutical Co., Ltd.) derived from Bacillus macerans was used instead of α-glucosyltransferase derived from Bacillus stearothermophilus. / Dextrin g was added and the reaction was carried out at 55 ° C. for 40 hours, and the same procedure as in Example 4 was carried out to obtain a powder sample B-2.

Comparative Example 5 In Comparative Example 4, in the same manner as in Comparative Example 4 except that the Bacillus megaterium-derived α-glucosyltransferase, which was prepared as described above, was used instead of the Bacillus macerans-derived α-glucosyltransferase. Powder sample B-3
Got

Comparative Example 6 A powder sample B-BL was obtained in the same manner as in Example 4 except that 100 g of the dextrin solution of Gymnema sylvestre leaf extract was freeze-dried as it was without adding an enzyme.

[Evaluation of bitterness / astringency] (a) Powder samples A-1, A-2, A-3, and A-BL 6 obtained in Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3
% Aqueous solution was prepared, and the degree of bitterness / astringency was evaluated by 10 panelists.

The results are shown in Table 2. The evaluations in Tables 2 and 3 are the average values of 10 panelists. Also, in the evaluation column,
“−” Indicates that bitterness / astringency is not sensed, “+” indicates that bitterness / astringency is sensed, and the bitterness / astringency is stronger as the number of “+” increases.

(B) 11 of powder samples B-1, B-2, B-3 and B-BL obtained in Example 4, Comparative Example 4, Comparative Example 5 and Comparative Example 6
% Aqueous solution was prepared, and the degree of bitterness / astringency was evaluated by 10 panelists. The results are shown in Table 3.

From the above results, the following can be seen.

That is, in the α-glucosyl transferase derived from Bacillus stearothermophilus used in the present invention, the alcohol extract extract powder 1 of Gymnema sylvestre leaves was used, and dextrin was used in an amount of 2.0 times as much as Gymnema. Although the bitterness and astringency of Sylvestre leaf extract were removed, α-derived from Bacillus macerans shown in Comparative Example 1
Glucosyltransferase and Bacillus shown in Comparative Example 2
With the α-glucosyltransferase derived from megaterium, the bitterness and astringency of Gymnema sylvestre leaf extract cannot be sufficiently improved even if dextrin is used in the above amount. Furthermore, even when dextrin was used in an amount of 4.5 times the amount of the extract powder 1, α derived from Bacillus macerans shown in Comparative Example 4 was used.
-Glucosyltransferase and Bacillus shown in Comparative Example 5
Removal of bitterness and astringency is not sufficient with megaterium-derived α-glucosyltransferase.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Suzuki 1-6-41 Iwasaki Nishi, Ichihara City, Chiba Prefecture Toyo Seika Co., Ltd. Chiba Plant (56) References Japanese Patent Laid-Open No. Sho 64-2552 (JP, A)

Claims (2)

[Claims] 1. A Bacillus stearothermophilus-derived α-glucosyltransferase is allowed to act on a Gymnema sylvestre leaf extract in the presence of less than 5 times the solid weight of the extract in the presence of starch. A method for removing bitterness and astringency of Gymnema sylvestre leaf extract, which comprises subjecting glycosides to α-glucosylation. 2. An α-glucosyltransferase derived from Bacillus stearothermophilus is allowed to act on Gymnema sylvestre leaf extract in the presence of a starch substance in an amount of 0.1 times or more and less than 5 times the solid weight of the extract. The method of claim 1, wherein: