JP2004008102A - Method for producing coffee aroma liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for effectively obtaining aroma components useful as a food additive from the residue of coffee extract and to provide a method for improving flavor of food using the aroma components thus obtained. <P>SOLUTION: The method for producing a coffee aroma liquid comprises a process of adding an alkali solution to the residue of the coffee extract to prepare a pH8-14 coffee suspension, and a process of volatilizing water from the coffee suspension under a reduced-pressure condition and condensing the water containing the aroma components. <P>COPYRIGHT: (C)2004,JPO

Description

本発明者は、さらに鋭意検討を重ね、コーヒー抽出残渣に残留する香気成分を風味を損ねることなく回収できる方法を見出し、本発明を完成するに至った。
【００１１】
即ち、本発明のコーヒー香気液の製造方法は、コーヒー抽出残渣にアルカリ溶液を加えて、ｐＨ８〜１４（２０℃）のコーヒー懸濁液を調製する工程、および前記コーヒー懸濁液を減圧条件下にて水分を蒸散させ、香気成分を含んだ水分を凝縮させてコーヒー香気液を得る工程
を含むことを特徴とする。
【００１２】
前記アルカリ溶液は、強塩基を含むことが好ましい。
【００１３】
前記コーヒー懸濁液のｐＨは、ｐＨ１０〜１３（２０℃）であることが好ましい。
【００１４】
前記蒸散が７〜５５ｋＰａの減圧条件下で行われ、前記凝縮が２〜１０℃の冷却条件下で行われることが好ましい。
【００１５】
また、本発明の食品の風味を改善する方法は、前記本発明の製造方法により得られたコーヒー香気液をコーヒー液または食品に添加することを特徴とする。
【００１６】
［作用効果］
本発明のコーヒー香気液の製造方法によると、コーヒー抽出残渣にアルカリ溶液を加えて、酸化を防止しつつ、減圧、低温条件下で香気液を得ることにより、香気成分を有効に抽出することができる。
【００１７】
本発明の食品の風味を改善する方法によると、本発明の製造方法により得られたコーヒー香気液をコーヒー液または食品に添加することで、コーヒーの良好な風味を付与するとともに添加されるコーヒー液または食品の独特な臭いをマスキングする効果を奏する。
【００１８】
【発明の実施の形態】
以下、本発明の実施の形態について、説明する。
【００１９】
本発明におけるコーヒー抽出残渣とは、缶コーヒーなどの用途に工業的に抽出された後のコーヒー豆をいう。通常、前記抽出は、焙煎コーヒー豆の重量に対して５〜２０倍の熱水を加水し、大気圧下にて行う。このような抽出条件で得られたコーヒー抽出残渣は、コーヒー豆の約２０〜３０重量％の固形分が抽出されている。
【００２０】
前記コーヒー抽出残渣は、全重量の約６０〜７５重量％程度の水分を含有しているが、本発明においては脱水や乾燥などの処理は特に必要ない。
【００２１】
本発明のコーヒー香気液の製造方法は、まず、コーヒー抽出残渣にアルカリ溶液を加えて、ｐＨ８〜１４（２０℃）のコーヒー懸濁液を調製する工程を行う。
【００２２】
コーヒー抽出残渣に加えるアルカリ溶液は、コーヒー懸濁液のｐＨを８〜１４に調節するためのものであり、食品に添加可能な成分を含むものであれば特に制限されるものではない。前記成分としては、強塩基、弱塩基等が挙げられる。ｐＨ調節が容易で添加量が少なくて済むことから、前記アルカリ溶液は、強塩基の水溶液が好ましく、水酸化カリウム水溶液、水酸化ナトリウム水溶液等が例示される。
【００２３】
前記アルカリ溶液の添加量は、コーヒー抽出残渣の重量の１〜１０倍程度であればよい。効率的な香気成分の捕集の観点から、２〜４倍の添加量が好ましい。
【００２４】
前記コーヒー懸濁液は、アルカリ溶液の添加によってｐＨが８〜１４に調節される。本発明におけるｐＨとは、特記しない限り、２０℃でｐＨメーターにより測定した値である。コーヒー懸濁液のｐＨは、良好な香気成分の回収率を上げ、香気液のマスキング効果を高めるためには、ｐＨ１０〜１３が好ましく、ｐＨ１１〜１３がより好ましい。
【００２５】
次に、前記コーヒー懸濁液を減圧条件下にて水分を蒸散させ、香気成分を含んだ水分を凝縮させてコーヒー香気液を得る工程を行う。
【００２６】
前記蒸散は、大気圧未満の減圧条件下で行われるものであり、特に制限されるものではないが、蒸散効率と良好な香気成分の回収の観点から、７〜５５ｋＰａの減圧条件下で行われることが好ましく、２５〜５０ｋＰａの減圧条件がより好ましい。蒸散時のコーヒー懸濁液は、香気成分の質を維持しつつ蒸散時間を短縮するために、９５℃程度まで加温してもよい。コーヒー懸濁液からの水の蒸発温度は、３５〜８５℃程度である。
【００２７】
前記凝縮は、香気成分を含む蒸散した水分を液体として回収するためのものであり、良好な香気成分を回収するためには２〜１０℃の冷却条件下で行われることが好ましく、２〜５℃がより好ましい。
【００２８】
前記凝縮は、公知の装置および方法を用いて行えばよい。
【００２９】
凝縮させる量は、特に制限されるものではないが、添加するアルカリ溶液の２〜２０重量％であることが好ましい。２重量％未満では香気成分の回収率が低く、２０重量％を超えると回収される香気成分の品質が劣る傾向がある。
【００３０】
このようにして得られたコーヒー香気液は、質・量ともに優れた香気成分を含み、コーヒーの風味を添加する目的でコーヒー液または他の食品に香料として使用することができる。
【００３１】
本発明の食品の風味の改善方法は、前記コーヒー香気液をコーヒー液または食品に添加することを特徴とする。
【００３２】
前記コーヒー香気液をコーヒー液に添加する場合は、所望のコーヒー濃度とコーヒーの風味となるように添加量を調整する。前記コーヒー香気液を食品に添加する場合は、所望のコーヒーの風味を有する程度に添加量を調整する。しかし、コーヒー香気液の過剰な添加は、逆に異臭を伴う場合があるので注意を要する。
【００３３】
また、本発明の食品の風味の改善方法は、添加対象のコーヒー液または食品の独特な臭いをマスキングする目的にも利用される。この場合は、コーヒー懸濁液のｐＨを１２以上にして得られたコーヒー香気液を用いることが好ましい。
【００３４】
【実施例】
以下、本発明の構成と効果を具体的に示す実施例等について説明する。
【００３５】
［コーヒー固形分の濃度］
コーヒー固形分の濃度は、減圧乾燥法により測定した。すなわち、コーヒー液２ｇを秤量し、５ｋＰａの圧力下にて７０℃で１６時間保持して乾燥重量を測定し、コーヒー液に対する重量％で表した。
【００３６】
［ガスクロマトグラフィーによる香気量の測定］
実施例および比較例等において、測定試料液１０ｍｌを、２２ｍｌのバイアル瓶に採取し、密栓した。密栓したバイアル瓶を、Ｔｅｋｍａｒ社製ガスクロマトグラフィー用オートサンプラにて８０℃で２０分間加温した後サンプリングし、ガスクロマトグラフィーで分析した。
【００３７】
測定条件
測定装置：日立製ガスクロマトグラフィーＧ−３０００
カラム：ジーエルサイエンス（株）製ＴＣ−ＷＡＸ　０．５３ｍｍ×３０ｍ
キャリヤーガス：ヘリウム
キャリヤーガス流量：１ｍｌ／分
カラム温度：４０℃（５分）→２２０℃（５℃／分で昇温）
検出器：ＦＩＤ。
【００３８】
ガスクロマトグラフィー分析によるピークの総面積を、総香気量として算出し、基準となる試料の値を１００％として比較した。また、各ピークを分析時のカラム温度を基に下記のように３つのエリアに分類し、各エリア別のピーク面積を算出し、香気成分の構成を調べた。
【００３９】
高沸点エリア：カラム温度１０１℃〜２００℃
中沸点エリア：カラム温度４１℃〜１００℃
低沸点エリア：カラム温度４０℃。
【００４０】
［実施例１］
焙煎し粉砕したコーヒー豆に対し、１２倍重量の１００℃の熱水を加えて、コーヒー豆固形分の約２５重量％を抽出し、コーヒー抽出残渣を得た。
【００４１】
得られたコーヒー抽出残渣２００ｇに、１％ｗ／ｖの水酸化カリウム水溶液４００ｇを添加して、ｐＨ１２（２０℃）のコーヒー懸濁液を調製した。前記コーヒー懸濁液を加温し、４０ｋＰａの減圧下にて８０℃の温度で水分を蒸散させた。
【００４２】
蒸散した水分を凝縮器に導入し、５℃にて凝縮させ、コーヒー香気液５０ｇを捕集した。得られたコーヒー香気液について、ガスクロマトグラフィーにより香気成分の構成を調べた。
【００４３】
［比較例１］
焙煎し粉砕したコーヒー豆に対し、１２倍重量の１００℃の熱水を加えて、コーヒー豆固形分の約２５重量％を抽出し、コーヒー抽出残渣を得た。
【００４４】
得られたコーヒー抽出残渣２００ｇに、１％ｗ／ｖの炭酸水素ナトリウム水溶液４００ｇを添加して、ｐＨ７．４（２０℃）のコーヒー懸濁液を調製した。前記コーヒー懸濁液を加温し、４０ｋＰａの減圧下にて８０℃の温度で水分を蒸散させた。
【００４５】
蒸散した水分を凝縮器に導入し、５℃にて凝縮させ、コーヒー香気液５０ｇを捕集した。得られたコーヒー香気液について、ガスクロマトグラフィーにより香気成分の構成を調べた。
【００４６】
［比較例２］
焙煎し粉砕したコーヒー豆に対し、１２倍重量の１００℃の熱水を加えて、コーヒー豆固形分の約２５重量％を抽出し、コーヒー抽出残渣を得た。
【００４７】
得られたコーヒー抽出残渣２００ｇに、脱イオン水４００ｇを添加して、ｐＨ５．７（２０℃）のコーヒー懸濁液を調製した。前記コーヒー懸濁液を加温し、４０ｋＰａの減圧下にて８０℃の温度で水分を蒸散させた。
【００４８】
蒸散した水分を凝縮器に導入し、５℃にて凝縮させ、コーヒー香気液５０ｇを捕集した。得られたコーヒー香気液について、ガスクロマトグラフィーにより香気成分の構成を調べた。
【００４９】
【表２】

表２より、アルカリ条件下で捕集した実施例１の香気液は、低沸点部の比率が高いが、中性または弱酸性条件下で捕集した比較例の香気液は、刺激成分を含むとされる高沸点部の比率が高い。実施例１の香気液は、低沸点部が５０％以上を占めるレギュラーコーヒー抽出液に近い構成を示すことがわかる。
【００５０】
［実施例２］
焙煎し粉砕したコーヒー豆に対し、１２倍重量の１００℃の熱水を加えて、コーヒー豆固形分の約２５重量％を抽出し、コーヒー抽出残渣を得た。
【００５１】
得られたコーヒー抽出残渣２００ｇに、１％ｗ／ｖの水酸化カリウム水溶液４００ｇを添加して、ｐＨ１２．９（２０℃）のコーヒー懸濁液を調製した。前記コーヒー懸濁液を加温し、４０ｋＰａの減圧下にて８０℃の温度で水分を蒸散させた。
【００５２】
蒸散した水分を凝縮器に導入し、５℃にて凝縮させ、コーヒー香気液を５０ｇづつ２つに分画し、計１００ｇの凝縮水を捕集した。各画分について、２０℃におけるｐＨおよびガスクロマトグラフィーによる香気成分の構成を調べた。
【００５３】
【表３】

表３より、捕集された凝縮水が添加したアルカリ溶液の１２．５重量％を越える（即ち、５０〜１００ｇ画分）と、香気成分の高沸点部の比率が３０％を越えることがわかる。高沸点部の増加は、刺激臭や異臭を伴うため、高沸点部の比率を一定限度以下に押える必要がある。このことから、捕集する凝縮水量は、添加したアルカリ溶液の２〜２０重量％程度に留めておく方が望ましい。
【００５４】
［評価試験１］
実施例１ならびに比較例１および２で得られたコーヒー香気液を、工業用減圧濃縮コーヒー液（固形分４３．６重量％）を飲用濃度に希釈したもの（固形分１．１７重量％）に、それぞれ２．５重量％添加して評価試料を調製した。対照として、前記減圧濃縮コーヒー液を脱イオン水で同じ濃度に希釈した試料を準備した。前記試料を７０℃に加温し、パネラーにより風味を評価した。
【００５５】
【表４】

表４より、減圧濃縮した工業用コーヒーへの添加試験では、実施例１のアルカリ条件下で回収した香気液の添加により、減圧濃縮コーヒー特有の加熱臭がマスキングされた。また、比較例１の中性条件下および比較例２の弱酸性条件下で回収した香気液の添加では、高沸点成分由来の異臭が確認されたが、実施例１の香気液の添加では異臭は認められなかった。
【００５６】
［評価試験２］
実施例１および比較例２で得られたコーヒー香気液を、工業用減圧濃縮コーヒー液（固形分４３．６重量％）を飲用濃度に希釈したもの（固形分１．１７重量％）に、それぞれ２．５重量％または５．０重量％添加して評価試料を調製した。対照として、香気液を添加しない試料を準備した。前記試料を７０℃に加温し、パネラーにより風味を評価した。
【００５７】
【表５】

表５より、実施例１で得られた香気液を添加した試料は、原料のコーヒー液に由来する加熱臭がマスキングされた。しかし、添加量を５．０重量％に増加させると、香気液に由来する異臭が感じられた。したがって、本発明の香気液は、少量の添加で効果を奏し、過剰な添加は逆効果になることがわかる。
【００５８】
［評価試験３］
焙煎し粉砕したコーヒー豆に対し、１２倍重量の１００℃の熱水を加えて、コーヒー豆固形分の約２５重量％を抽出し、コーヒー抽出残渣を得た。
【００５９】
得られたコーヒー抽出残渣２００ｇに、それぞれ０〜０．５２％ｗ／ｖの水酸化カリウム水溶液４００ｇを添加して、コーヒー懸濁液を調製した。前記コーヒー懸濁液を加温し、４０ｋＰａの減圧下にて８０℃の温度で水分を蒸散させた。蒸散した水分を凝縮器に導入し、５℃にて凝縮させ、コーヒー香気液を５０ｇ捕集した。
【００６０】
得られたコーヒー香気液を、工業用減圧濃縮コーヒー液（固形分４３．６重量％）を飲用濃度に希釈したもの（固形分１．１７重量％）に、それぞれ２．５重量％添加して評価試料を調製した。対照として、香気液の代わりに脱イオン水を２．５重量％添加した試料も調製した。前記試料を７０℃に加温し、パネラーにより風味を評価した。
【００６１】
【表６】

［加熱臭］○：原料のコーヒー液に由来する加熱臭を感じない
△：原料のコーヒー液に由来する加熱臭を多少感じる
×：原料のコーヒー液に由来する加熱臭を感じる
［異臭］　○：香気液に由来する異臭を感じない
△：香気液に由来する異臭を多少感じる
×：香気液に由来する異臭を感じる
表６より、香気液の回収をｐＨ８以上の条件下で行なうことにより、得られた香気液は、原料のコーヒー液に由来する加熱臭をマスキングする効果があることがわかる。また、香気液の回収をｐＨ１２以上の条件下で行なうことにより、刺激臭などの異臭を伴わない高品質の香気液を得ることがわかる。なお、０％ｗ／ｖの水酸化カリウム水溶液（水酸化カリウム無添加）で得られた香気液を添加した試料は、異臭が非常に強く、原料のコーヒー液に由来する加熱臭の判別ができなかった。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a coffee flavor liquid and a method for improving the flavor of food. The present invention is a method useful for improving the flavor of food by effectively recovering the flavor components of coffee from the residue after coffee extraction.
[0002]
[Prior art]
Generally, roasted coffee beans contain about 30% by weight of soluble solids. Usually, extraction means that 80 to 90% of these solids are eluted with hot water or the like. In addition, the aroma component contained in the extract together with the solid content of the coffee has a great effect on the quality of the coffee.
[0003]
Some of the extracted coffee beans are used as compost or feed, but most of them are discarded as coffee extraction residue (leather), which requires a large cost.
[0004]
Therefore, a method for effectively utilizing the coffee extraction residue is desired.
[0005]
With respect to the recovery of the active ingredient remaining in the coffee extraction residue, Japanese Patent Application Laid-Open No. 5-168411 describes a method for extracting a soluble component by explosion treatment of the coffee extraction residue. Food flavor improvers consisting of products obtained by high-temperature and high-pressure treatment of beans or coffee extraction residues are described.
[0006]
As for the use of the fragrance component of the coffee extraction residue, JP-A-2000-135059 describes a method of recovering the fragrance component by extracting the extraction residue with steam.
[0007]
[Problems to be solved by the invention]
However, all of the above-mentioned methods for recovering from coffee extraction residues treat the coffee extraction residues at high temperatures to collect solids and aroma components, and the treatment at high temperatures promotes the oxidation of coffee and lowers the pH. This causes a problem that the flavor of the collected matter is impaired.
[0008]
Therefore, an object of the present invention is to provide a method for effectively obtaining a flavor component useful as a food additive from a coffee extraction residue, and a method for improving the flavor of food using the obtained flavor component.
[0009]
[Means for Solving the Problems]
The present inventors standardized the coffee liquid of each fraction in the extraction process as shown in Table 1 below to the drinking concentration and compared the total aroma amount by gas chromatography. As a result, the solid concentration of the extracted liquid decreased. It was found that the fragrance component eluted also did not decrease. That is, since the extraction of the solid content and the fragrance component is not uniform, it indicates that a large amount of the fragrance component held by the coffee remains in the residue that is discarded due to the reduced amount of the solid content eluted.
[0010]
[Table 1]

The present inventor has further studied diligently and found a method capable of recovering aroma components remaining in a coffee extraction residue without impairing the flavor, and has completed the present invention.
[0011]
That is, the method for producing a coffee aroma liquid of the present invention comprises the steps of: adding an alkaline solution to a coffee extraction residue to prepare a coffee suspension having a pH of 8 to 14 (20 ° C.); And evaporating the water to condense the water containing the aroma component to obtain a coffee aroma liquid.
[0012]
The alkaline solution preferably contains a strong base.
[0013]
The coffee suspension preferably has a pH of 10 to 13 (20 ° C.).
[0014]
Preferably, the transpiration is performed under a reduced pressure condition of 7 to 55 kPa, and the condensation is performed under a cooling condition of 2 to 10 ° C.
[0015]
Further, the method for improving the flavor of a food according to the present invention is characterized in that the coffee flavor liquid obtained by the production method of the present invention is added to a coffee liquid or a food.
[0016]
[Effects]
According to the method for producing a coffee fragrance liquid of the present invention, an alkali solution is added to a coffee extraction residue to prevent oxidation, and while obtaining a fragrance liquid under reduced pressure and low temperature conditions, it is possible to effectively extract a fragrance component. it can.
[0017]
According to the method for improving the flavor of food of the present invention, by adding the coffee flavor or the coffee flavor liquid obtained by the production method of the present invention to a coffee liquid or a food, the coffee liquid is imparted with a good flavor of coffee and added. Or it has the effect of masking the unique smell of food.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0019]
The coffee extraction residue in the present invention refers to coffee beans that have been industrially extracted for use such as canned coffee. Usually, the extraction is carried out under atmospheric pressure by adding hot water 5 to 20 times the weight of the roasted coffee beans. In the coffee extraction residue obtained under such extraction conditions, a solid content of about 20 to 30% by weight of the coffee beans is extracted.
[0020]
The coffee extraction residue contains about 60-75% by weight of the total weight of water, but in the present invention, treatments such as dehydration and drying are not particularly required.
[0021]
In the method for producing a coffee aroma liquid of the present invention, first, an alkaline solution is added to a coffee extraction residue to prepare a coffee suspension having a pH of 8 to 14 (20 ° C.).
[0022]
The alkaline solution to be added to the coffee extraction residue is for adjusting the pH of the coffee suspension to 8 to 14, and is not particularly limited as long as it contains components that can be added to food. Examples of the component include a strong base and a weak base. Since the pH can be easily adjusted and the amount of addition is small, the alkaline solution is preferably an aqueous solution of a strong base, and examples thereof include an aqueous solution of potassium hydroxide and an aqueous solution of sodium hydroxide.
[0023]
The amount of the alkaline solution added may be about 1 to 10 times the weight of the coffee extraction residue. From the viewpoint of efficient collection of aroma components, the addition amount is preferably 2 to 4 times.
[0024]
The pH of the coffee suspension is adjusted to 8 to 14 by adding an alkaline solution. Unless otherwise specified, the pH in the present invention is a value measured by a pH meter at 20 ° C. The pH of the coffee suspension is preferably from pH 10 to 13, more preferably from pH 11 to 13, in order to increase the recovery rate of a favorable fragrance component and enhance the masking effect of the fragrance liquid.
[0025]
Next, a step of evaporating moisture in the coffee suspension under reduced pressure conditions and condensing moisture containing an aroma component to obtain a coffee aroma liquid is performed.
[0026]
The transpiration is performed under reduced pressure conditions below atmospheric pressure, and is not particularly limited, but is performed under reduced pressure conditions of 7 to 55 kPa from the viewpoint of transpiration efficiency and good fragrance component recovery. The pressure is preferably reduced to 25 to 50 kPa. The coffee suspension at the time of evaporation may be heated to about 95 ° C. in order to shorten the evaporation time while maintaining the quality of the aroma components. The evaporation temperature of water from the coffee suspension is about 35 to 85 ° C.
[0027]
The condensation is for recovering the evaporated water containing the fragrance component as a liquid, and is preferably performed under a cooling condition of 2 to 10 ° C. in order to recover a good fragrance component. C is more preferred.
[0028]
The condensation may be performed using a known device and method.
[0029]
The amount to be condensed is not particularly limited, but is preferably 2 to 20% by weight of the added alkaline solution. If the amount is less than 2% by weight, the recovery rate of the fragrance component is low, and if it exceeds 20% by weight, the quality of the recovered fragrance component tends to be inferior.
[0030]
The coffee flavor liquid obtained in this way contains a flavor component excellent in quality and quantity, and can be used as a flavor in coffee liquid or other foods for the purpose of adding coffee flavor.
[0031]
The method for improving the flavor of a food according to the present invention is characterized in that the coffee flavor liquid is added to the coffee liquid or the food.
[0032]
When the coffee flavor liquid is added to the coffee liquid, the addition amount is adjusted so that the desired coffee concentration and coffee flavor are obtained. When the coffee flavor liquid is added to food, the amount is adjusted to such an extent as to have a desired coffee flavor. However, it should be noted that excessive addition of the coffee fragrance liquid may cause an unpleasant odor.
[0033]
Further, the method for improving the flavor of a food according to the present invention is also used for the purpose of masking a unique smell of a coffee liquid or a food to be added. In this case, it is preferable to use a coffee flavor liquid obtained by adjusting the pH of the coffee suspension to 12 or more.
[0034]
【Example】
Hereinafter, examples and the like specifically illustrating the configuration and effects of the present invention will be described.
[0035]
[Concentration of coffee solids]
The coffee solids concentration was measured by a vacuum drying method. That is, 2 g of the coffee liquid was weighed, kept at 70 ° C. for 16 hours under a pressure of 5 kPa, and the dry weight was measured, and expressed as a percentage by weight based on the coffee liquid.
[0036]
[Measurement of aroma amount by gas chromatography]
In Examples and Comparative Examples, 10 ml of the measurement sample solution was collected in a 22 ml vial and sealed. The sealed vial was heated at 80 ° C. for 20 minutes using a gas chromatography autosampler manufactured by Tekmar, sampled, and analyzed by gas chromatography.
[0037]
Measuring conditions Measuring device: Hitachi Gas Chromatography G-3000
Column: TC-WAX 0.53 mm x 30 m, manufactured by GL Sciences Corporation
Carrier gas: Helium carrier gas flow rate: 1 ml / min Column temperature: 40 ° C. (5 minutes) → 220 ° C. (heating at 5 ° C./min)
Detector: FID.
[0038]
The total area of the peaks in the gas chromatography analysis was calculated as the total odor, and the comparison was made with the value of the reference sample as 100%. Further, each peak was classified into the following three areas based on the column temperature at the time of analysis, the peak area for each area was calculated, and the configuration of the fragrance component was examined.
[0039]
High boiling point area: Column temperature 101 ° C to 200 ° C
Medium boiling point area: Column temperature 41 ° C to 100 ° C
Low boiling point area: column temperature 40 ° C.
[0040]
[Example 1]
To the roasted and ground coffee beans, 12 times the weight of hot water at 100 ° C. was added to extract about 25% by weight of the solids of the coffee beans to obtain a coffee extraction residue.
[0041]
400 g of a 1% w / v aqueous potassium hydroxide solution was added to 200 g of the obtained coffee extraction residue to prepare a coffee suspension having a pH of 12 (20 ° C.). The coffee suspension was heated and water was evaporated at a temperature of 80 ° C. under a reduced pressure of 40 kPa.
[0042]
The evaporated water was introduced into a condenser, condensed at 5 ° C., and 50 g of a coffee flavor liquid was collected. About the obtained coffee flavor liquid, the composition of the flavor component was examined by gas chromatography.
[0043]
[Comparative Example 1]
To the roasted and ground coffee beans, 12 times the weight of hot water at 100 ° C. was added to extract about 25% by weight of the solids of the coffee beans to obtain a coffee extraction residue.
[0044]
400 g of a 1% w / v aqueous sodium hydrogen carbonate solution was added to 200 g of the obtained coffee extraction residue to prepare a coffee suspension having a pH of 7.4 (20 ° C.). The coffee suspension was heated and water was evaporated at a temperature of 80 ° C. under a reduced pressure of 40 kPa.
[0045]
The evaporated water was introduced into a condenser, condensed at 5 ° C., and 50 g of a coffee flavor liquid was collected. About the obtained coffee flavor liquid, the composition of the flavor component was examined by gas chromatography.
[0046]
[Comparative Example 2]
To the roasted and ground coffee beans, 12 times the weight of hot water at 100 ° C. was added to extract about 25% by weight of the solids of the coffee beans to obtain a coffee extraction residue.
[0047]
400 g of deionized water was added to 200 g of the obtained coffee extraction residue to prepare a coffee suspension having a pH of 5.7 (20 ° C.). The coffee suspension was heated and water was evaporated at a temperature of 80 ° C. under a reduced pressure of 40 kPa.
[0048]
The evaporated water was introduced into a condenser, condensed at 5 ° C., and 50 g of a coffee flavor liquid was collected. About the obtained coffee flavor liquid, the composition of the flavor component was examined by gas chromatography.
[0049]
[Table 2]

According to Table 2, the fragrance liquid of Example 1 collected under alkaline conditions has a high ratio of low boiling points, but the fragrance liquid of Comparative Example collected under neutral or weakly acidic conditions contains a stimulating component. The ratio of the high boiling point part is high. It can be seen that the fragrance liquid of Example 1 has a structure close to a regular coffee extract in which the low boiling point portion accounts for 50% or more.
[0050]
[Example 2]
To the roasted and ground coffee beans, 12 times the weight of hot water at 100 ° C. was added to extract about 25% by weight of the solids of the coffee beans to obtain a coffee extraction residue.
[0051]
400 g of a 1% w / v aqueous potassium hydroxide solution was added to 200 g of the obtained coffee extraction residue to prepare a coffee suspension having a pH of 12.9 (20 ° C.). The coffee suspension was heated and water was evaporated at a temperature of 80 ° C. under a reduced pressure of 40 kPa.
[0052]
The evaporated water was introduced into a condenser and condensed at 5 ° C., and the coffee aroma liquid was fractionated into two pieces of 50 g each, and a total of 100 g of condensed water was collected. For each fraction, the pH at 20 ° C. and the composition of the aroma components were determined by gas chromatography.
[0053]
[Table 3]

From Table 3, it can be seen that when the collected condensed water exceeds 12.5% by weight of the added alkali solution (that is, 50 to 100 g fraction), the ratio of the high boiling point portion of the fragrance component exceeds 30%. . Since an increase in the high boiling point portion is accompanied by a pungent odor or an unpleasant odor, it is necessary to keep the ratio of the high boiling point portion below a certain limit. For this reason, it is desirable to keep the amount of condensed water to be collected at about 2 to 20% by weight of the added alkaline solution.
[0054]
[Evaluation Test 1]
The coffee aroma liquid obtained in Example 1 and Comparative Examples 1 and 2 was diluted to a potable concentration of an industrial vacuum concentrated coffee liquid (solids 43.6% by weight) (solids 1.17% by weight). And 2.5% by weight of each were added to prepare evaluation samples. As a control, a sample was prepared by diluting the above-described concentrated coffee liquid to the same concentration with deionized water. The sample was heated to 70 ° C., and the flavor was evaluated by a panel.
[0055]
[Table 4]

As shown in Table 4, in the test for addition to the industrial coffee concentrated under reduced pressure, the heating odor peculiar to the concentrated coffee under reduced pressure was masked by the addition of the fragrance liquid recovered under the alkaline conditions of Example 1. Further, in the addition of the fragrance liquid collected under the neutral condition of Comparative Example 1 and the weakly acidic condition of Comparative Example 2, an off-flavor derived from a high-boiling component was confirmed. Was not found.
[0056]
[Evaluation Test 2]
The coffee aroma liquid obtained in Example 1 and Comparative Example 2 was diluted to a drinking concentration (solid content: 1.17% by weight) of industrial vacuum concentrated coffee liquid (solid content: 43.6% by weight), respectively. An evaluation sample was prepared by adding 2.5% by weight or 5.0% by weight. As a control, a sample to which no flavor liquid was added was prepared. The sample was heated to 70 ° C., and the flavor was evaluated by a panel.
[0057]
[Table 5]

As shown in Table 5, the sample to which the fragrance liquid obtained in Example 1 was added was masked from the heating odor derived from the coffee liquid as the raw material. However, when the addition amount was increased to 5.0% by weight, an off-flavor due to the fragrance was felt. Therefore, it can be seen that the fragrance liquid of the present invention is effective when added in a small amount, and that an excessive addition has an adverse effect.
[0058]
[Evaluation Test 3]
To the roasted and ground coffee beans, 12 times the weight of hot water at 100 ° C. was added to extract about 25% by weight of the solids of the coffee beans to obtain a coffee extraction residue.
[0059]
400 g of an aqueous solution of 0 to 0.52% w / v potassium hydroxide was added to 200 g of the obtained coffee extraction residue to prepare a coffee suspension. The coffee suspension was heated and water was evaporated at a temperature of 80 ° C. under a reduced pressure of 40 kPa. The evaporated water was introduced into a condenser, condensed at 5 ° C., and 50 g of coffee flavor liquid was collected.
[0060]
The obtained coffee aroma liquid was added to an industrial vacuum concentrated coffee liquid (solid content: 43.6% by weight) diluted to a drinking concentration (solid content: 1.17% by weight), and 2.5% by weight was added. An evaluation sample was prepared. As a control, a sample to which 2.5% by weight of deionized water was added instead of the fragrance liquid was also prepared. The sample was heated to 70 ° C., and the flavor was evaluated by a panel.
[0061]
[Table 6]

[Heating odor] ○: Feel no heating odor derived from the raw coffee liquor △: Feel some heating odor derived from the raw coffee liquor ×: Feel the heating odor derived from the raw coffee liquor [Off-flavor] ○: No off-flavor due to perfume is felt. Δ: Some off-flavour is derived from perfume. X: Off-flavor is perceived from perfume. From Table 6, the recovery of perfume is carried out under conditions of pH 8 or higher. It can be seen that the obtained aromatic liquid has an effect of masking a heated odor derived from the raw coffee liquid. In addition, it can be seen that by performing the recovery of the fragrance liquid under the condition of pH 12 or more, a high-quality fragrance liquid free of off-flavor such as pungent odor is obtained. In addition, the sample added with the fragrance liquid obtained with a 0% w / v aqueous potassium hydroxide solution (without addition of potassium hydroxide) has a very strong odor, and the heated odor derived from the raw coffee liquid can be discriminated. Did not.

Claims (5)

A step of preparing a coffee suspension having a pH of 8 to 14 (20 ° C.) by adding an alkaline solution to the coffee extraction residue, and evaporating water from the coffee suspension under reduced pressure to obtain a water containing an aroma component. For producing a coffee fragrance liquid, comprising the step of condensing water to obtain a coffee fragrance liquid. 2. The method of claim 1, wherein said alkaline solution comprises a strong base. The method according to claim 1 or 2, wherein the coffee suspension has a pH of 10 to 13 (20 ° C). The method according to any one of claims 1 to 3, wherein the transpiration is performed under reduced pressure conditions of 7 to 55 kPa, and the condensation is performed under cooling conditions of 2 to 10C. A method for improving the flavor of a food, comprising adding a coffee flavor liquid obtained by the method according to any one of claims 1 to 4 to a coffee liquid or a food.