JP4109731B2 - Improved guava leaf extract extraction method - Google Patents

Description

【０００１】
【産業上の利用分野】
本発明は、グアバ葉から、良質のエキスを得るための改良抽出法に関する。
【０００２】
【従来技術と発明が解決すべき課題】
古来、中国を始め東南アジア諸国において、グアバ葉を煎じた水溶液を止瀉、胃腸薬として飲用されているほか、パーラ茶と称し茶の代用ともなっている。近年、我が国でも、グアバ葉抽出液が糖尿病を始め、高血圧、便秘、肥満、下痢等に有効であるとして、注目を集めている。グアバ葉には多量のタンニン、ビタミン類、フラボノール、精油等が含まれており、それらのいずれかの成分が単独で、あるいは総合的に上記の効果を奏すると考えられている。従って、特定の疾患の治療のみならず一般的な健康維持のためにもグアバ葉エキスの需要が高まっているが、長時間煎じる方法は、極めて面倒で困難なため、より簡便に利用でき、流通に適したグアバ葉エキスが市場に提供されている。それらのエキスは、主に水−アルコール又は低級ケトン溶媒で工業的にグアバ葉を抽出することで得られるが、このようにして得られるエキスは青臭い不快臭があって不味い上、水溶解性も良くない（１ｇを水２００ｍｌに溶かしても濁る）等の問題点を有していた。
【０００３】
【課題を解決するための手段】
本発明者らは、風味と水溶解性の良いグアバ葉エキスを効率良く得る方法を開発するために鋭意、研究を重ねた結果、グアバ葉を抽出溶媒で抽出して得られる抽出液を適宜濃縮して得られる部分濃縮液から、難溶性の成分を除去すると、従来のグアバ葉エキスにおける風味や水溶解性に関する問題が解決されることを見い出し、本発明を完成した。
即ち、本発明は、グアバ葉を水又は親水性溶媒、又はこれらの混合物により抽出し、得られた抽出液を部分濃縮し、部分濃縮液から抽出溶媒に難溶性の物質を除去した後、部分濃縮液を再度濃縮することを特徴とするグアバ葉エキスの製造方法を提供するものである。
このようにして得られたグアバ葉エキス（以下、エキスということもある）は、従来のエキスに特有の不快臭や不味さがなく、風味が良い上、水溶解性にも優れており、食品、医薬品、医薬部外品等に用いることができる。
【０００４】
【発明を実施するための最良の形態】
本発明方法は、１）グアバ葉の抽出、２）部分濃縮及び濃縮液の処理、及び３）再濃縮の３工程に大別できるが、第１の工程は、従来グアバ葉の抽出に用いられていた既知の方法で行うことができる。しかしながら、良質のエキスを効率良く得るには、グアバ葉を、水又は親水性溶媒、又はこれらの混合物で抽出する。親水性溶媒としては第一級アルコール又は低級ケトンが好ましく、メタノール、エタノール、ブタノール等のアルコール及びアセトンがより好ましい。最も好ましいのは、エタノールである。また、水溶性成分とアルコール又は低級ケトンに可溶性の成分とを充分に抽出するために、水とこれらの親水性溶媒との混合溶媒で抽出することが好ましい。通常、水と混合溶媒の配合比は、６：４〜３：７の範囲であるが、これに限定されない。また、抽出溶媒の使用量はグアバ葉の状態によって異なるが、乾燥グアバ葉の場合、重量比で８〜１０倍の溶媒を用いる。
抽出温度も任意であるが、５０〜７０℃に加温し、常圧又は１〜１．５ｋｇ／ＣＭ^２の加圧下に、数十分から数時間抽出する。
【０００５】
部分濃縮するためには、抽出液を、室温〜７０℃、好ましくは３０〜４０℃で体積が原液の約１〜１０割、好ましくは約５〜６割になるまで、減圧濃縮する。
濃縮液から抽出溶媒に難溶性の物質を除去する方法としては、部分濃縮液を低温条件下で放置し、固液分離して沈降性物質を除去する方法（沈降法）と、部分濃縮液を炭化水素溶剤で処理し、有機溶剤可溶性成分を除去する方法（抽出法）があり、いずれの方法でも目的の良質のエキスを得ることができる。或いは、これらの方法を適宜併用してもよい。
沈降法の場合、部分濃縮液を０〜５０℃、好ましくは５〜２０℃の低温条件下で、沈降するに十分な時間、通常、５〜２４時間放置して不溶性成分を沈降させ、遠心分離又は減圧ろ過して固液分離する。
また、抽出法の場合、部分濃縮液を、その約０．５〜３倍の容量の炭化水素系溶剤、例えばヘキサン、ヘプタン等で、室温で抽出し、分液して該溶剤に可溶性の成分を除去する。
【０００６】
次いで、処理後の部分濃縮液を上記同様に、そのまま又は減圧下に適当な量まで濃縮する。得られた最終濃縮液（液状エキス）はこのままでも使用できるが、スプレードライ又は凍結乾燥して粉末エキスとしてもよい。この粉末エキスは、従来法で得られたグアバ葉エキスは水溶解性に優れ（１ｇ／２００ｍｌでも濁らない）、淡色で、青臭み等の不快な匂いや味がなく、飲食に適する。
なお、上記の部分濃縮及び／又は得られた部分濃縮液の処理における条件等（濃縮の程度、沈降の程度、抽出溶媒の種類等）を適宜選択することにより、所望の性質を備えたエキスを得ることができ、そのような改良法も本発明の範囲に包含される。
【０００７】
このように、本発明方法によれば、通常の抽出法で抽出される成分中、有用な成分は含有するが、味、臭い、色等に好ましくない影響を及ぼす成分を含有しない良質のエキスを得ることができる。このことは、タンニン等の有用成分をより濃縮し、かつ品質が向上されうることを意味する。加えて、本発明方法によれば、既存の設備を用いて、効率良く簡便に良質のエキスが得られるのである。
得られたエキスは、グアバ葉の有用成分を含有しているので、健康食品、健康飲料、医薬品等の原料として、広範囲に利用できる。
【０００８】
以下に実施例を挙げて本発明を説明する。
実施例１
粉砕した乾燥グアバ葉２００ｇに水−エタノール（１：１）の混合液１３２０ｍｌを加え、６０〜６２℃で１時間加熱する。濾紙でろ過し、残渣に上記と同様の混合液６８０ｍｌを加えて再度抽出し、合計１４４０ｍｌのろ液を得た。このろ液から４０ｍｌを取り、約４０℃で減圧濃縮してアルコールを除去した後、凍結乾燥をして原液抽出工キス０．９３ｇを得た。残りのろ液１４００ｍｌを２８０ｍｌずつに５等分（Ａ〜Ｅ）し、それぞれ、以下のように処理した。
Ａ：そのまま５℃の冷蔵庫に入れ、１０時間沈降させた後、２０００ｒｐｓｘ６ｍｉｎで遠心分離して固液分離する。沈殿はそのまま冷凍乾燥し、沈殿Ａ０．３２ｇを得た。液体は上記と同様、約４０℃で減圧濃縮してアルコールを除去した後、凍結乾燥しで、抽出エキスＡ６．３ｇを得た。
Ｂ：約４０℃で１８０ｍｌまで減圧濃縮し、濃縮液を上記のＡの場合と同様に、５℃での沈降、遠心による固液分離処理を行い、液体は約４０℃で減圧濃縮してアルコールを除去した後、凍結乾燥して、抽出エキス末Ｂ５．６ｇを得た。固体はそのまま冷凍乾燥して沈殿Ｂ０．８５ｇを得た。
Ｃ〜Ｅ：Ｃは、約４０℃で１５０ｍｌまで、Ｄは１３０ｍｌまで、Ｅは１００ｍｌまでそれぞれ減圧濃縮した後、上記Ｂと同様に処理して、抽出エキスＣ、Ｄ、Ｅ及び沈殿Ｃ、Ｄ、Ｅを得た。
得られた各エキス末及び沈殿のタンニン含有量を定量した。結果を以下の表１に示す。
【０００９】
実施例２
粉砕した乾燥グアバ葉５０ｇに水−エタノール（１：１）の混合液３３０ｍｌを加え、６５℃で１時間加熱した。濾紙でろ過し、残渣に上記と同様の混合液１７０ｍｌを加えて再び抽出し、合計３６０ｍｌのろ液を得た。このろ液を約４０℃で１６０ｍｌまで減圧濃縮し、２等分（Ｆ及びＧ）し、それぞれ、以下のように処理した。
Ｆ：１５℃の冷蔵庫に入れ、一晩沈降させた後、２０００ｒｐｓｘ６ｍｉｎで遠心分離して固液分離する。沈殿はそのまま冷凍乾燥し、沈殿Ｆ１．１ｇを得た。液体は上記と同様、約４０℃で減圧濃縮してアルコールを除去した後、凍結乾燥して、抽出エキス末Ｆ３．２ｇを得た。
Ｇ：５０ｍｌのｎ−ヘキサンで３回抽出した後、分液によりｎ−ヘキサン層を除き、水層を約４０℃で減圧濃縮して有機溶剤を除去した後、凍結乾燥して２．３ｇのヘキサン処理エキス（抽出エキスＧ）を得た。
得られた各エキス末Ｆ及びＧのタンニン含有量を定量した結果、両者のタンニン含有量はほぼ同様（Ｆ：Ｇ＝１：１．０１）であった。
☆
【表１】

【００１０】
実施例３
粉砕した乾燥グアバ葉２００ｇに水−エタノール（１：１）の混合液１３２０ｍｌを加え、６０〜６２℃で１時間加熱した。濾紙でろ過し、残渣に上記と同様の混合液６８０ｍｌを加えて再び抽出し、合計１５４０ｍｌのろ液を得た。このろ液を約４０℃で８５０ｍｌまで部分濃縮した。この部分濃縮液は５℃の冷蔵庫に入れ、１０時間沈降させた後、減圧ろ過による固液分離処理を行い、液体は約４０℃で減圧濃縮してアルコールを除去した後、凍結乾燥して抽出エキスＨ３１．９ｇを得た。固体はそのまま凍結乾燥して沈殿Ｈ６．３３ｇを得た。
得られた抽出エキスＨ及び沈殿Ｈの成分分析を行った。結果を以下の表２に示す。
☆
【表２】

【００１１】
【発明の効果】
上記実施例、及び表１及び２に記載の結果から明らかなように、本発明方法によれば、良質のグアバ葉エキスを得ることができる。[0001]
[Industrial application fields]
The present invention relates to an improved extraction method for obtaining a high-quality extract from guava leaves.
[0002]
[Prior art and problems to be solved by the invention]
Since ancient times, in China and other Southeast Asian countries, guava leaves decocted aqueous solution has been used as a gastrointestinal medicine, and it is also called “Pala tea” and is used as a substitute for tea. In recent years, guava leaf extract has attracted attention in Japan as it is effective for diabetes, as well as high blood pressure, constipation, obesity, diarrhea and the like. Guava leaves contain a large amount of tannins, vitamins, flavonols, essential oils, etc., and any of these components is considered to have the above-mentioned effects singly or comprehensively. Therefore, the demand for guava leaf extract is increasing not only for the treatment of specific diseases but also for general health maintenance, but the method of brewing for a long time is extremely troublesome and difficult, so it can be used more easily and distributed. A guava leaf extract suitable for the market is available on the market. These extracts are obtained mainly by industrially extracting guava leaves with water-alcohol or a lower ketone solvent, but the extract obtained in this way has a blue unpleasant odor and is unpleasant and also has water solubility. There was a problem such as bad (1 g dissolved in 200 ml of water makes it turbid).
[0003]
[Means for Solving the Problems]
As a result of intensive research and research to develop a method for efficiently obtaining a guava leaf extract having good flavor and water solubility, the inventors of the present invention appropriately concentrated an extract obtained by extracting guava leaf with an extraction solvent. It was found that removing the poorly soluble component from the partially concentrated solution obtained in this way solves the problems related to the flavor and water solubility of the conventional guava leaf extract, and the present invention has been completed.
That is, the present invention extracts guava leaves with water or a hydrophilic solvent, or a mixture thereof, partially concentrates the obtained extract, removes a substance that is hardly soluble in the extract solvent from the partially concentrated solution, The present invention provides a method for producing a guava leaf extract, wherein the concentrate is concentrated again.
The guava leaf extract thus obtained (hereinafter sometimes referred to as “extract”) has no unpleasant odor or taste unique to conventional extracts, has a good flavor, and is excellent in water solubility. It can be used for foods, pharmaceuticals, quasi drugs and the like.
[0004]
BEST MODE FOR CARRYING OUT THE INVENTION
The method of the present invention can be broadly divided into three steps: 1) extraction of guava leaves, 2) partial concentration and treatment of the concentrate, and 3) reconcentration. The first step is conventionally used for extraction of guava leaves. Can be carried out by known methods. However, in order to efficiently obtain a good quality extract, guava leaves are extracted with water or a hydrophilic solvent, or a mixture thereof. As the hydrophilic solvent, primary alcohols or lower ketones are preferable, and alcohols such as methanol, ethanol, butanol, and acetone are more preferable. Most preferred is ethanol. Further, in order to sufficiently extract the water-soluble component and the component soluble in alcohol or lower ketone, it is preferable to extract with a mixed solvent of water and these hydrophilic solvents. Usually, the compounding ratio of water and the mixed solvent is in the range of 6: 4 to 3: 7, but is not limited thereto. Moreover, although the usage-amount of an extraction solvent changes with the state of a guava leaf, in the case of a dry guava leaf, the solvent of 8-10 times is used by weight ratio.
The extraction temperature is arbitrary, warmed to 50-70 ° C., atmospheric pressure or under pressure of 1~1.5kg / CM ^2, it extracts from several tens of minutes to several hours.
[0005]
For partial concentration, the extract is concentrated under reduced pressure at room temperature to 70 ° C., preferably 30 to 40 ° C. until the volume is about 1 to 100%, preferably about 5 to 60% of the stock solution.
As a method for removing a substance that is hardly soluble in the extraction solvent from the concentrated solution, the partially concentrated solution is allowed to stand under low temperature conditions, and the precipitated material is removed by solid-liquid separation (precipitation method). There is a method (extraction method) of treating with a hydrocarbon solvent to remove organic solvent soluble components, and any method can obtain the desired high-quality extract. Or you may use these methods together suitably.
In the case of the sedimentation method, the partially concentrated solution is left at a low temperature of 0 to 50 ° C., preferably 5 to 20 ° C. for a time sufficient for sedimentation, usually 5 to 24 hours to precipitate insoluble components, and then centrifuged. Alternatively, solid-liquid separation is performed under reduced pressure.
In the case of the extraction method, the partially concentrated liquid is extracted with a hydrocarbon solvent having a volume of about 0.5 to 3 times, for example, hexane, heptane, etc., at room temperature, separated, and soluble in the solvent. Remove.
[0006]
Subsequently, the partially concentrated liquid after the treatment is concentrated to an appropriate amount as it is or under reduced pressure in the same manner as described above. The obtained final concentrated liquid (liquid extract) can be used as it is, but may be spray-dried or freeze-dried to obtain a powder extract. As for this powder extract, the guava leaf extract obtained by the conventional method is excellent in water solubility (not turbid even at 1 g / 200 ml), is light in color, has no unpleasant odor and taste such as blue odor, and is suitable for eating and drinking.
It should be noted that an extract having desired properties can be obtained by appropriately selecting the conditions in the above partial concentration and / or processing of the obtained partial concentrate (concentration, sedimentation, type of extraction solvent, etc.). Such improved methods are also within the scope of the present invention.
[0007]
Thus, according to the method of the present invention, a high-quality extract that contains useful components among components extracted by a normal extraction method but does not contain components that adversely affect the taste, smell, color, etc. Obtainable. This means that useful components such as tannin can be further concentrated and the quality can be improved. In addition, according to the method of the present invention, a high-quality extract can be obtained efficiently and simply using existing equipment.
Since the obtained extract contains useful components of guava leaves, it can be widely used as a raw material for health foods, health drinks, pharmaceuticals and the like.
[0008]
Hereinafter, the present invention will be described with reference to examples.
Example 1
1320 ml of a mixed solution of water-ethanol (1: 1) is added to 200 g of the pulverized dry guava leaf and heated at 60 to 62 ° C. for 1 hour. It filtered with the filter paper, 680 ml of the same liquid mixture as the above was added to the residue, and extracted again, and a total of 1440 ml of filtrate was obtained. 40 ml was taken from this filtrate, concentrated under reduced pressure at about 40 ° C. to remove the alcohol, and freeze-dried to obtain 0.93 g of a stock solution extraction kiss. The remaining 1400 ml of the filtrate was divided into 5 equal portions (A to E) in 280 ml portions and treated as follows.
A: Place in a refrigerator at 5 ° C. as it is, settling for 10 hours, and then centrifuge at 2000 rps × 6 min for solid-liquid separation. The precipitate was freeze-dried as it was to obtain 0.32 g of precipitate A. Similarly to the above, the liquid was concentrated under reduced pressure at about 40 ° C. to remove the alcohol, and then freeze-dried to obtain 6.3 g of extract A.
B: Concentrated under reduced pressure to about 180 ml at about 40 ° C., and the concentrated solution was subjected to solid-liquid separation by sedimentation and centrifugation at 5 ° C. as in the case of A above, and the liquid was concentrated under reduced pressure at about 40 ° C. And then lyophilized to obtain 5.6 g of extract powder B. The solid was freeze-dried as it was to obtain 0.85 g of precipitate B.
C to E: C was concentrated at about 40 ° C. up to 150 ml, D was reduced to 130 ml, E was concentrated to 100 ml under reduced pressure, and then treated in the same manner as B to extract extracts C, D, E and precipitates C, D , E was obtained.
Each extract powder obtained and the tannin content of the precipitate were quantified. The results are shown in Table 1 below.
[0009]
Example 2
To 50 g of the pulverized dry guava leaf, 330 ml of a mixed solution of water-ethanol (1: 1) was added and heated at 65 ° C. for 1 hour. The residue was filtered through a filter paper, and 170 ml of the same mixture as above was added to the residue and extracted again to obtain a total of 360 ml of filtrate. The filtrate was concentrated under reduced pressure at about 40 ° C. to 160 ml, divided into two equal parts (F and G), and each was treated as follows.
F: Place in a refrigerator at 15 ° C. and allow to settle overnight, then centrifuge at 2000 rps × 6 min for solid-liquid separation. The precipitate was freeze-dried as it was to obtain 1.1 g of precipitate F. In the same manner as above, the liquid was concentrated under reduced pressure at about 40 ° C. to remove the alcohol, and then lyophilized to obtain 3.2 g of extract extract powder F.
G: After extracting three times with 50 ml of n-hexane, the n-hexane layer was removed by liquid separation, the aqueous layer was concentrated under reduced pressure at about 40 ° C. to remove the organic solvent, and then lyophilized to obtain 2.3 g of A hexane-treated extract (extracted extract G) was obtained.
As a result of quantifying the tannin contents of the obtained extract powders F and G, the tannin contents of both were substantially the same (F: G = 1: 1.01).
☆
[Table 1]

[0010]
Example 3
To 200 g of the pulverized dry guava leaf, 1320 ml of a mixed solution of water-ethanol (1: 1) was added and heated at 60 to 62 ° C. for 1 hour. It filtered with the filter paper, 680 ml of the same liquid mixture as the above was added to the residue, and extracted again, and a total of 1540 ml of filtrate was obtained. The filtrate was partially concentrated at about 40 ° C. to 850 ml. This partially concentrated solution is placed in a refrigerator at 5 ° C. and allowed to settle for 10 hours, and then subjected to solid-liquid separation by filtration under reduced pressure. The liquid is concentrated under reduced pressure at about 40 ° C. to remove alcohol, and then freeze-dried and extracted. 31.9 g of extract H was obtained. The solid was lyophilized as it was to obtain 6.33 g of precipitated H.
Component analysis of the obtained extract H and precipitate H was performed. The results are shown in Table 2 below.
☆
[Table 2]

[0011]
【The invention's effect】
As is clear from the above examples and the results described in Tables 1 and 2, according to the method of the present invention, a good quality guava leaf extract can be obtained.

Claims (3)

グアバ葉を水又は親水性溶媒、又はこれらの混合物により抽出し、得られた抽出液を部分濃縮し、部分濃縮液から抽出溶媒に難溶性の物質を除去した後、部分濃縮液を再度濃縮することを特徴とするグアバ葉エキスの製造方法。  Extract guava leaves with water or a hydrophilic solvent, or a mixture of these, partially concentrate the resulting extract, remove hardly soluble substances in the extract from the partially concentrated solution, and then concentrate the partially concentrated solution again. A method for producing a guava leaf extract. 部分濃縮が、室温〜７０℃において、元の抽出液の体積の５０〜８０％になるまで減圧濃縮することにより行われる請求項１記載の方法。The method according to claim 1, wherein the partial concentration is performed under reduced pressure at room temperature to 70 ° C until the volume of the original extract reaches 50 to 80% . 難溶性の物質の除去を、部分濃縮液を５〜２０℃で放置して沈降する物質を除去すること、及び／又は、部分濃縮液を炭化水素溶剤で処理し、有機溶剤可溶性成分を除去することにより行う請求項１又は２のいずれかに記載の方法。To remove the hardly soluble substance, the partially concentrated liquid is allowed to stand at 5 to 20 ° C. to remove the precipitated substance, and / or the partially concentrated liquid is treated with a hydrocarbon solvent to remove organic solvent soluble components. The method according to claim 1, wherein the method is performed.