JPS62166861A - Extraction and purification of sweetener component from dry leaf of stevia - Google Patents

Abstract

PURPOSE:To obtain a high-purity sweetener component free from astringent taste and smell, by extracting a sweetener component from dried stevia leaf and precipitating and adsorbing impurities of the component with CaCl2 and an Al.Mg compound oxide adsorbent. CONSTITUTION:Dried leaf of Stevia rebaudiana Bertoni (a plant of Compositae family) is extracted with 7-14 times weight of water at 50-70 deg.C for 3-6hr under agitation or circulation to obtain a brown liquid extract ( having a total solid content of 2-3%) containing 0.7-0.8% sweetener component such as whole stevioside. The extract liquid is subjected to pH-adjustment and concentrated 7-8 times at about 60 deg.C under reduced pressure. The concentrated liquid is added with 0.5-2wt% CaCl2 to separate a most part of impurities as flocculent precipitate. Successively, the extract is added with an Al.Mg compound oxide adsorbent of an amount corresponding to 15-20wt% of the solid content at 40-55 deg.C under vigorous agitation to effect the adsorption of the above flocculent precipitate and dissolved metallic ions. After leaving at rest for 1-2hr, the mixture is filtered by precise filtration to obtain a filtrate. If necessary, the whole stevioside partially adsorbed to the adsorbent is recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to a plant of the chrysanthemum family Stevia rebaudiana B.
E RTONl, hereinafter abbreviated as stevia. ) is related to a method for extracting and purifying the sweet components of each stalk contained in the fruit.

(Prior Art) Stevia, which is native to Paraguay and adjacent areas in South America, has been used by indigenous peoples since ancient times as a "sweet tea" and as a natural sweetness resource.

There are several types of sweet components contained in Stevia leaves, and depending on the variety, stevioside, rebaudioside A, C, D, E, etc. have been reported.

Traditionally, stevioside has a sweetness that is 150 to 200 times sweeter than sugar, and is closer to the sweetness of sugar than the synthetic sweeteners saccharin, glycyrrhizin from licorice, and phyllodultin from sweet tea, but it has a residual taste and an astringent taste. Baudionide group is said to remain in the body during the day and cause discomfort, while the Baudionide group is said to be 250 to 300 times sweeter than sugar and have superior taste quality.

Various attempts have been made to produce products with high rebaudioside content.

For example, (a) Breeding of stevia with high rebaudioside content (b) Method of transferring a glucose group to the -R8 group of stevioside using β-glycosyltransferase (Japanese Patent Application Laid-Open No. 1987-9976B, 57-43659, 5B-78562, 59-48059) <C) Method of isolating stevioside and rebaudioside from a coexisting solution (JP-A-56-121453-5, JP-A-57-862)
64) There was.

(Problem to be solved by the invention) However, from an industrial standpoint, the stevia varieties that are already widely cultivated worldwide have a stevioside content of 80%.
%, rebaudioside content of 20% is the mainstream, and there are problems in that (a) and (C) are difficult to treat, and (b) is uneconomical due to increased costs. Ta.

(Means for Solving the Problems) As a result of various experiments, the present inventors have determined that stevioside itself does not have bitterness, astringency, or odor, but that the taste quality, which was conventionally considered a drawback, is due to the extraction and purification process of stevioside. In addition to confirming that the impurities and stevioside mixed in during the process were decomposed and becoming steviol biocide, we also completely separated and removed the impurities to prevent stevioside from deteriorating, and ensure that the stevioside contained in stevia vegetables was not contaminated. We have developed a method to simultaneously extract and purify stevioside and rebaudioside groups, which are sweet components.

That is, the present invention uses calcium chloride to form a floc-like precipitate of sweet components extracted from dried leaves of Stevia rebaudiana Bertoni with hot water and the impurities extracted at the same time.
This is a method for extracting and purifying sweet components from dried stevia leaves, which is then adsorbed and separated using an aluminum/magnesium composite oxide adsorbent to completely remove astringency and odor components.

The present invention will be explained in more detail.

The present invention first involves adding 50% water to 7 to 14 times the amount of dried Stevia leaves.
The brown extract is extracted at a temperature of 3 to 70 degrees Celsius while stirring or circulating for 3 to 6 hours. This extract contains 0.7 to 0.8% of total stevioside (hereinafter, the total amount of stevioside and rebaudioside groups is referred to as total stevioside), and the solid content is 2 to 3%, so total stevioside is contained. This means that three to four times the amount of impurities is mixed in.

If we continue to adsorb impurities or precipitate, a large amount of adsorbent and flocculant will be required, so we adjust the pH to avoid deterioration and concentrate to 7 to 8 times the concentration at 60°C under reduced pressure. do. Calcium chloride corresponding to 0.5 to 2% by weight of this concentrated extract is added to convert most of the impurities into floc-like precipitates.
The aluminum/magnesium composite oxide adsorbent (hereinafter referred to as MgO adsorbent) corresponding to 40 to 5%
While maintaining the liquid temperature at 5°C, add it while stirring vigorously to remove not only floc-like precipitates but also dissolved Ca++ and 3i".
After adsorbing metal ions such as No. 1, the mixture is allowed to stand for 1 to 2 hours and then subjected to precision filtration to obtain a filtrate.

Furthermore, in order to recover the total stevioside that is partially adsorbed on the MgO-based adsorbent, the adsorbent is washed with hot water at 60°C to 80°C, and the obtained washing liquid and filtrate are combined by microfiltration again to remove impurities. The concentrated extract is obtained by removing the .

In this solution, the ratio of solid content % to total stevioside content % increased from 3 to 4:1 before treatment to 1.5:1, indicating that impurities were significantly removed. .

Since the solution has a pH of 9 to 10 and stevioside gradually decomposes over time, it is quickly neutralized for subsequent purification.

The present inventors adopted a process to selectively adsorb total stevioside using a porous resin manufactured by Mitsubishi Kasei Corporation (product name HP-20), but as it is, the pH is too high and the adsorption power of the resin is reduced. Not only will this decrease, but there is also a risk that minute precipitation will occur.

Therefore, the pH was once adjusted to 4.5 with 2 to 3% hydrochloric acid, and precipitates such as proteins were precipitated in an acidic region, and Mg
After preventing the generation of minute crystals such as (OH)2, it is neutralized to pH 6 to 7 with 3 to 5% caustic soda.

Hereinafter, total stevioside is selectively adsorbed onto a porous resin made of styrene/divinylbenzene polymer, eluted with methanol or ethanol, and then desalted using a strongly acidic cation exchange resin, followed by weakly basic anion exchange. Decolorize with resin.

This eluate is again concentrated under reduced pressure, treated with an ultrafiltration membrane to remove colored substances such as decomposed products of chlorophyll, and spray-dried to produce a white powder of total stevioside.

(Effects of the Invention) Since the present invention is as described above, impurities mixed in during the extraction and purification process of stevionide are completely separated and removed.
As a result, it is possible to obtain sweet ingredients without astringency or odor.

(Example) Hereinafter, implementation of the present invention will be described.

Thoroughly loosen I kg of Stevia dry leaves, add 10 people's warm water, and stir slowly while maintaining the temperature at 60℃ for 3 minutes.
Time extracted. After thoroughly draining the extraction residue, it was extracted again with the same amount of hot water at 60°C for 1 hour, and the extract and residue were completely separated using a centrifuge and combined with the first extraction solution. When the extraction residue is dried and compared with the same water content as stevia dried leaves, which is 9%, the weight reduction is 45 to 5%.
Since the total stevioside content of the dried Stevia leaves was 12%, it is clear that other water-soluble components were mixed into the extract as impurities.

When this extract was analyzed, the pH ranged from 15.8 to 6.2.
It was found that the solid content was 2.8 to 3.2%, and the total stevioside was 0.7 to 0.8%, which was extracted and contaminated with impurities equivalent to 3 to 4 times the total stevioside. did.

Calcium chloride corresponding to 5% of the solid content is added to this extract to generate precipitation of impurities, and the pH is adjusted to 5.
It was adjusted to 3 to 5.5 to prevent deterioration.

After passing the above extract through a 200-mesh stainless steel net to remove floc-like precipitates and crushed pieces of stevia dry leaves, the extract was heated to 7 to 8 ℃ while maintaining the product temperature at 60℃ under reduced pressure.
It was concentrated to double the concentration.

This concentrated extract has a pH of 5 to 5.5 and a solid content of 15 to 1.
Since the total stevioside is 6.5 to 7%, it still contains twice as many impurities as the total stevioside, so I dissolved calcium chloride equivalent to 5% of the solid content in advance and dissolved it again. was added to the extract while stirring to generate a floc-like precipitate, and then allowed to stand for 30 minutes.

Subsequently, M corresponding to 20% of the solid content of the concentrated extract was added.
The gO-based adsorbent was added as a powder to the extract while vigorously stirring and while maintaining the liquid temperature at 50°C or higher, to remove not only the floc-like precipitate caused by the addition of calcium chloride, but also the
Coloring substances, astringent components, odor components, oil drop substances, Ca++, 3i+, etc. that are still dissolved or cloudy,
In the subsequent ion-exchange resin process, metal ions that act as inhibitory factors were adsorbed.

The solution was allowed to stand for 2 hours while being kept warm, and then the adsorbent and the impurities adsorbed thereon were separated from the extracted filtrate using a qualitative filter paper in a Buchner funnel set in a suction bottle. Stevioside is partially adsorbed in the filtered residue, so the temperature at 80°C
This was washed with hot water, and the washing liquid and the extraction filtrate were combined.

Since this solution has a pH of 9.5 to 10, it is first adjusted to pH 4.5 with 2% hydrochloric acid, the precipitate separated using a filter paper, and then neutralized with 3% caustic soda to give a pH of 7.

Through the above treatment, the extracted concentrate becomes a transparent brownish-brown solution, but since it still contains more than the same amount of impurities as the total stevioside, a further purification process using an ion exchange resin was used, the combination of which is as follows: It is.

(1) Selective adsorption with porous resin and elution process with methanol Manufactured by Mitsubishi Chemical Corporation Product name HP-20゜HP-21
Manufactured by Organo Co., Ltd. Product name Amberlight XAD-
2, XAD-4, etc. (Demetallization ion process using strongly acidic cation exchange resin. Manufactured by Mitsubishi Kasei Corporation. Product name: 5K-IB, etc. Manufactured by Organo Corporation. Product name: Amberlite IR-1.
208 etc. (3) Colored substance removal process using weakly basic anion exchange resin Manufactured by Mitsubishi Kasei Corporation Product name WA-30 etc. Manufactured by Organo Co., Ltd. Product name Amberlite IRA-
After testing the performance of each resin, the inventors determined that HP-93 etc.
20 for 2000d! , 5K-IB for 300d.

Each 600 d of WA-30 was filled into an acrylic resin cylinder and used.

A concentrated extract at 3°C was obtained from which impurities were removed as much as possible in the previous steps, and the total stevioside content of this solution was 3°C.
．． The solid content was 8%.

First, the solution was passed through HP-20 at 5V-1.5 to selectively adsorb total stevioside onto the resin, and after thoroughly washing with pure water, total stevioside was eluted with 80% methanol at 2°C to form an intermediate solution. And so.

The temperature of this intermediate solution was 4.5°C, and the methanol content was 45%.
Most of the total stevioside was recovered by passing it through a 5K-1B column as it was, and then through a WA-30 resin cylinder, but some of the total stevioside that had been adsorbed together with the coloring substances was washed with 80% methanol. It was completely eluted by running 1.

The temperature of the collected liquid from the ion exchange resin process and the eluate together is 7°C, and the total stevioside content is only 1.5%, so they are concentrated under reduced pressure again to recover methanol, and the solid content is 10% and the total stevioside content is only 1.5%. Stevioside 9% solution 1
Obtained 170d.

Therefore, 1 kg of stevia dry leaves contains 120 g of total stevioside, and 105 g is recovered in the solution, so the yield of extraction and purification is 87.5
%Met.

The solution was a clear liquid with a slight yellowish tinge, but in order to further purify it completely, it was treated with an ultrafiltration membrane having ultra-fine pores with a molecular weight of FF 13,000 to obtain a transparent liquid. Taste tests have shown that this clear liquid has a taste similar to that of sugar, and the disadvantages of stevioside, such as astringency, bitterness, and odor, have been completely eliminated. There is no need to increase the percentage.

This clear liquid was further concentrated under reduced pressure to obtain a total steviocytide concentration of 1560
% concentrate, or add 4 to 5 times the amount of 95%
When methanol is added and the mixture is cooled to below 10°C and allowed to stand, crystals are obtained, which are vacuum dried to produce a 95% pure stevioside product.

If this transparent liquid is spray-dried as it is, a stevioside product with a purity of 85% will be obtained.Depending on market requirements, a stevioside product with a purity of 50 to 55% can be produced by adding dextrin or the like and spray-drying.

January 20, 1986 2 people outside

Claims (1)

[Claims] Impurities extracted at the same time as sweet components extracted with hot water from dried leaves of Stevia Rebaudiana Bertoni are made into floc-like precipitates with calcium chloride, and then adsorbed and separated using an aluminum-magnesium composite oxide adsorbent, resulting in astringent taste and odor. A method for extracting and purifying sweet components from dried Stevia leaves, which is characterized by completely removing the components.