JP2003192479A - Method for manufacturing stevia extract - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a stevia extract to improve the quality, to simplify the manufacture and to realize decrease in the manufacture cost. <P>SOLUTION: First, stevia stems after removing stevia leaves are dried to obtain powder, which is boiled in a pressurized state over the atmospheric pressure, and a solid content is removed to obtain an extract liquid. The extract liquid is heated and concentrated under reduced pressure. The extract liquid after concentration is subjected to primary fermentation by a fermenting machine, and the concentrated liquid after primary fermentation is further fermented and aged for 30 to 360 days to obtain a stevia extract. The potash produced during concentration is skimmed by using an about 50-number mesh. Impurities produced during fermentation and ageing are also removed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing stevia extract.

[0002]

BACKGROUND OF THE INVENTION Stevia extract is used as a material for growing useful microorganisms in soil in the agricultural field, as a growth promoting activator, as a nutritional supplement feed additive in the field of livestock, and as an active ingredient in health foods and various cosmetics. Is widely used. As a manufacturing method of this Stevia extract,
The method proposed in Japanese Patent No. 2577105 is known. In this method, dried stevia leaves and stems are crushed into powder, put in water and boiled to obtain a stevia extract, and the extract is concentrated, fermented and aged.

[0003]

However, in the above-mentioned method, the boiling and concentrating steps are very troublesome and the energy efficiency in concentrating is poor, resulting in high manufacturing cost. In addition, there is a problem in that a lot of holes are generated in the boiling and concentration steps, which suppresses fermentation and remains as an impurity to deteriorate the quality.

The present invention has been conceived from such a fact, and an object of the present invention is to provide a method for producing stevia extract, which has improved quality, is easy to produce, and can reduce the production cost.

[0005]

Means for Solving the Problems In order to achieve the above object, a method for producing a stevia extract according to the present invention is as follows: Stevia stalk powder is boiled under a pressure higher than atmospheric pressure, and then solid matter is removed. A step of obtaining an extract, a step of heating and concentrating the extract under a reduced pressure, a step of subjecting the concentrated extract to a primary fermentation by a fermenter, and a step of fermenting and aging the concentrated concentrate subjected to the primary fermentation And a step of performing. 0.2M inside the fermenter during the primary fermentation by the fermenter
The pressure may be increased to about Pa.

[0006] In the step of concentrating and / or the step of fermenting and aging, it is desirable to scrape off impurities or scoop out impurities. It is also possible to add a step of drying the liquid stevia extract described in any of the above into a powder form.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below based on Examples. Stevia, which is a raw material, is cultivated by pesticide-free organic cultivation in any of seedlings, cuttings, and seedlings, and mature ones are trimmed once a year (early October). For mowing, after removing the Stevia leaf by hand, remove the Stevia stem from the root.
It is done by cutting at about cm. Stevia leaves were found to produce a large amount of arbor during boiling, and it was found that this arbor causes fermentation inhibition and deterioration of purity. Therefore, the present invention does not use stevia leaves.

The Stevia stalks thus cut off are dried naturally or by a drier to have a water content of 5% to 10%. The dried Stevia stalks are pulverized to about 20 mesh to obtain Stevia stalk powder.

This Stevia stalk powder is boiled in water for extraction treatment. Conventionally, this extraction step has been carried out under atmospheric pressure by means of an atmospheric pressure pot. However, the hot water extraction and the heating concentration in the atmospheric pressure pot takes time and effort for the amount of heat. Therefore, in the present invention, the extraction processing is performed as follows.

First, 100 liters of water was added to 20 kg of the above-mentioned Stevia stalk powder, and the mixture was agitated.
Leave for 0 minutes. As a result, the dried powder of Stevia stalk absorbs water and becomes soft, making it easy to take out the active ingredient.

After that, in the pressure cooker, the pressure is higher than the atmospheric pressure by about 0.1.
It is heated to a temperature of 125 ± 10 ° C. and boiled under a pressure of 5 ± 0.02 MPa. Since the pressure is higher than atmospheric pressure in the pressure cooker, the boiling point rises to 125 ± 10 ° C., which promotes the elution of the active ingredient contained in the Stevia stalk and enables efficient extraction into hot water. The extraction time varies depending on the state of the Stevia stem powder, but is about 30 minutes to 1 hour.

The extract thus obtained is dehydrated to obtain an extract containing no solid content. The dehydration method is not particularly limited,
In this example, the product was placed in a cotton bag and dehydrated by a rotary dehydrator or a screw dehydrator to obtain about 80 liters of a complete extract containing no solid content.

Conventionally, the step of obtaining this extract has been carried out under atmospheric pressure. Therefore, it takes a lot of time to extract the active ingredient. The outline is as follows: Stevia leaf and stem powder is boiled in the boiling state for about 1 hour, squeezed with a squeezing machine to obtain the 1st extraction liquid, squeezed waste is boiled again for about 1 hour, and squeezed with a squeezing machine. The extract was obtained twice and the extract was obtained by mixing the first and second extracts. On the other hand, in the method of the present invention, since the pressure in the pressure cooker is increased to the atmospheric pressure or higher,
The temperature becomes high and the active ingredient can be extracted in a short time.

Next, about 80 liters of the extract from which the above solid content was removed was placed in a vacuum concentrator, and the temperature was adjusted to 80 ± 5 ° C.
Concentrate for about 2 hours under the pressure reduced to less than the atmospheric pressure of 0.06 ± 0.01 MPa to obtain about 60 liters of a concentrated liquid having a specific gravity of 1.3.

This step has conventionally been carried out by a method in which the above-mentioned mixed extract is boiled down under atmospheric pressure and concentrated. Therefore, the concentration did not proceed unless the temperature was raised to 100 ° C., which is the normal boiling point of water.

However, in the present invention, since the heat concentration is carried out under reduced pressure lower than the atmospheric pressure, the boiling point of the extract is lowered and the latent heat of vaporization is also reduced, so that both the time and the amount of heat required for concentration can be saved.

It was found that the surface of the extract was tainted during the concentration process, and this awning was the cause of inhibiting fermentation or inhibiting the active ingredient. Therefore, in the present invention, a net of about 50 mesh is rotated to scoop out the perforation. Once the concentration has proceeded, measure the sugar content of the concentrate and stop the concentration when it reaches 8 to 25 degrees.

The concentrate thus obtained is put into a fermenter and subjected to primary fermentation for 24 hours under the condition that the temperature is 30 ° C. and the pressure is about twice the atmospheric pressure of 0.2 ± 0.02 MPa. . The fermentation of Stevia is basically a natural fermentation in which Stevia is fermented with a yeast that naturally exists without adding yeast from the outside. Conventionally, the above concentrated solution was directly put into an aging tank for fermentation. However, according to this method, the amount of yeast contained in Stevia is small and various bacteria are easily mixed in. Therefore, only the mixed bacteria may grow and the concentrated solution may be spoiled, resulting in lack of stability of fermentation.
On the other hand, in the present invention, since the concentrated liquid is put into the fermenter and fermented at a predetermined temperature and a predetermined pressure, spoilage can be prevented and stable fermentation can be performed. That is, since many of the various bacteria do not have pressure resistance, it is easy to kill them or suppress their growth. On the other hand, the yeast required for fermentation has pressure resistance,
It can grow preferentially. As a result, it became possible to suppress the propagation of various bacteria and to perform stable fermentation.

When a fermenter is used, the fermentation period is 1
Although it can be shortened from / 2 to 1/3, a large number of fermenters are required. Therefore, the primary fermentation, that is, only the step of preferentially growing the above-mentioned yeast is performed in the fermenter, and the subsequent fermentation and aging are performed in the aging tank.

After the completion of the primary fermentation, the concentrated solution is transferred to an aging tank and aged at 25 to 40 ° C. for 30 to 360 days. The ripening period varies because the higher the sugar content, the longer the aging. In the above-mentioned Japanese Patent No. 2577105, the aging temperature was from 20 ° C to 25 ° C, but in the present invention, there is little darkness, and primary aging eliminates germs,
Due to the fact that the number of yeasts is increasing, it can be aged at a temperature of 25 ° C. or higher.
The ripening period shown in No. 7105 could be shortened to almost half the period. Impurities such as yeast carcasses and crystals are also generated during the fermentation and aging, so a net of about 70 mesh was rotated in the liquid so that these could be removed.

As described above, the fermentation of stevia is a natural fermentation without adding yeast, but in the case of promoting fermentation, yeast that has been cultured in advance is added to the concentrated liquid, and then the primary fermentation step or fermentation. An aging step may be performed.

The fermented and aged liquid thus obtained is stevia extract. This stevia extract is undiluted,
Alternatively, it is diluted with water before use. Since the stevia extract produced by the method of the present invention has high purity, the dilution ratio can be made larger than that of the conventional one. For example, foliar application to various fruit trees for agricultural use or soil watering, but conventional Stevia extract is 700-
The one diluted about 1000 times was used. On the other hand, the stevia extract produced by the production method of the present invention is 15
The same effect could be confirmed with the product diluted to 100 to 2000 times.

The above stevia extract is a liquid,
The liquid may be dried to give a powder. By making the extract into a dry powder form, it is possible to simplify storage or use. The powdery stevia extract may be used as it is, or may be used by dissolving it in water or the like. As a drying method, hot air drying may be used, but freeze drying is preferable because it hardly causes a change in quality.

[0024]

As described above, according to the present invention,
After boiling Stevia stalk powder under a pressure higher than atmospheric pressure, a step of removing the solid matter to obtain an extract, a step of heating and concentrating the extract under a reduced pressure below atmospheric pressure, and Since it has a step of first fermenting the concentrated extract with a fermenter and a step of fermenting and aging the concentrated concentrate that has been first fermented, a high quality stevia extract can be obtained at low cost.

Continued front page    F-term (reference) 2B150 AB03 BC06 DD42 DD57                 4B018 MD61 MF01 MF06 MF07 MF13                 4H011 AB04 BA01 BB08 BB22 DD03                       DE15                 4H061 AA02 CC41 EE61 EE66 GG13                       GG18 GG21 GG22 GG48

Claims (3)

[Claims] 1. A step of boiling stevia stalk powder in a state of being pressurized to atmospheric pressure or higher, and then removing solid matter to obtain an extract, and heating the extract in a state of being reduced in pressure to atmospheric pressure or less. The process of concentrating and the concentrated extract by fermenter 1
A method for producing a stevia extract, which comprises a step of secondary fermentation and a step of fermenting and aging the concentrated liquid subjected to primary fermentation. 2. The method for producing a stevia extract according to claim 1, wherein in the step of concentrating and / or the step of fermenting and aging, scraping or impurities are scraped off with a net. 3. A method for producing a stevia extract, characterized by comprising the step of drying the stevia extract according to claim 1 or 2 into a powder form.