JPH07322823A - Method for improving taste of extracted coffee liquid - Google Patents

Abstract

PURPOSE:To easily improve the taste of an extracted coffee liquid in high safety and obtain a treated liquid free from bitter taste by contacting an extracted coffee liquid with a cyclodextrin polymer to remove chlorogenic acid in the extracted liquid by adsorbing to the polymer and easily recovering and regenerating the used polymer. CONSTITUTION:An extracted coffee liquid is contacted with a cyclodextrin polymer (preferably a water-insoluble crushed particles or beads of a polymer composed of a-cyclodextrin, beta-cyclodextrin or gamma-cyclodextrin). Chlorogenic acid existing in the extract as a bitter taste component is adsorbed to the polymer and removed by this process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the taste of a coffee extract by removing chlorogenic acid in the coffee extract using a cyclodextrin polymer.

[0002]

2. Description of the Related Art Caffeine and chlorogenic acid are well known as taste components in a coffee extract. Caffeine dissolves well in water with a mild bitterness that doesn't leave behind. Chlorogenic acid is poorly soluble in water and exhibits bitterness, sourness and astringency. When this chlorogenic acid is present in the coffee extract more than necessary, the coffee extract not only exhibits a sour and bitter taste, but also causes haze and precipitate during storage.

Conventionally, a water-soluble cyclodextrin is added to drinking water to mask a glycoside having a bitter taste like chlorogenic acid (Japanese Patent Publication No. 59-31679), and chlorogenic acid is used as a synthetic resin. Kaisho 62-615
69) or ceramics (Japanese Patent Laid-Open No. 1-22)
Japanese Patent No. 8447) has proposed a method of removing by adsorption.

[0004]

However, in the method of adding water-soluble cyclodextrin, the solubility of cyclodextrin is generally low, so that it is difficult to add a sufficient amount to mask bitter substances such as chlorogenic acid. For this reason, sweeteners and seasonings have been added to prevent bitterness and astringency. Addition of sweeteners and seasonings often impaired the original taste of foods.

In the case of adsorption removal method using ceramics or synthetic resin (ion exchange resin, polystyrene resin, etc.), not only chlorogenic acid in the coffee extract but also other significant components such as caffeine are removed. There was a problem that it would end up.

Some of the synthetic resins such as polyvinylpyrrolidone resin, polyethylene resin, polyamide resin, etc. show selective adsorption to chlorogenic acid, but all have a problem in safety. However, there is a problem that the adsorption amount is small or the operability is difficult.

[0007]

The present invention provides a coffee extract comprising contacting a coffee extract with a cyclodextrin polymer, and adsorbing and removing chlorogenic acid in the extract by the cyclodextrin polymer. A method for improving taste is provided.

The present invention has been completed by finding that the water-insoluble cyclodextrin polymer selectively adsorbs chlorogenic acid in coffee extract. The cyclodextrin polymer used in the present invention has not only high selective adsorption capacity for chlorogenic acid, but also high safety because it polymerizes cyclodextrin, which is recognized as a natural additive to foods, and chlorogenic acid. It has an advantage that the cyclodextrin polymer having adsorbed bisphenol can be easily removed from the coffee extract.

The contact between the cyclodextrin polymer and the coffee extract is carried out by adding an appropriate amount of the cyclodextrin polymer into the coffee extract, for example, 0.1 with respect to the coffee extract.
After adding about 30 parts by weight, the mixture may be stirred and adsorbed, and then removed outside the system. Alternatively, chlorogenic acid may be removed by passing the coffee extract through a column packed with a cyclodextrin polymer. Generally, the space velocity (SV) of 0.5 to 2.0 is preferably adopted as the liquid passage rate.

The cyclodextrin polymer used in the present invention is a polymer composed of α-cyclodextrin, β-cyclodextrin and / or γ-cyclodextrin. 6 for each cyclodextrin,
It is a cyclic oligosaccharide in which 7 and 8 glucose are α-1,4 linked. Cyclodextrin polymer is α
One or two or more kinds of −, β- and γ-cyclodextrin may be used as a structural unit.

These water-insoluble cyclodextrin polymers are conventionally known polymers obtained by reacting cyclodextrin with a cross-linking agent such as epichlorohydrin, diepoxy compound, diisocyanate and acrylamide derivative and cyclodextrin. For example,
JP-B-60-11961 discloses a method for obtaining an insoluble polymer by dispersing a cyclodextrin polymerized to a degree not insolubilized with epichlorohydrin in liquid paraffin and adding a cross-linking agent while maintaining a predetermined temperature. JP-A-60-20924 discloses a method of obtaining an insoluble polymer by dispersing cyclodextrin, which has been polymerized to such an extent that it is not insolubilized in advance by a crosslinking agent, in the crosslinking agent and reacting it.

The shape and particle size of the water-insoluble cyclodextrin polymer are not particularly limited as the adsorbent and may be any shape such as beads or crushed particles. The particle size is also not particularly limited, but is preferably 300 μm or less from the viewpoint of polymer strength and the like.

The cyclodextrin polymer is put into the coffee extract and the chlorogenic acid is adsorbed, and the separation is easy even by spontaneous precipitation. On the other hand, the polyamide resin, which is the most general synthetic resin reported to selectively adsorb chlorogenic acid, has a poor sedimentation property and requires a special device. Further, the amount of chlorogenic acid adsorbed per unit weight of the cyclodextrin polymer is about twice that of the polyamide resin, which is an excellent adsorbability. The chlorogenic acid adsorbed on the cyclodextrin polymer is easily desorbed with a dilute acid, a dilute alkali or an aqueous solution of ethanol, so that it can be easily regenerated and reused.

[0014]

EXAMPLES The present invention will now be described in more detail with reference to examples. In the following examples, parts and% mean parts by weight and% by weight, unless otherwise specified.

Production Example Preparation of Water-Insoluble Cyclodextrin Polymer Powdered β-cyclodextrin (RINGDEX-
B, manufactured by Mercian Co., Ltd.) 10 g, water 9 ml was added and kneaded, and 50% sodium hydroxide aqueous solution 10 ml
And 100 mg of sodium borohydride were added to form a uniform solution. While maintaining this solution at 60 ° C,
3 ml of epichlorohydrin while stirring at a speed of 0 rpm
Was added dropwise over 15 minutes, and the mixture was further stirred for 30 minutes, 200 ml of liquid paraffin was added, and the mixture was stirred at a speed of 1000 rpm for 2 hours. The cyclodextrin polymer thus obtained was separated by filtration and washed with 100 ml of hexane three times and then with 100 ml of acetone three times to remove liquid paraffin. Furthermore, sodium hydroxide, sodium borohydride and water-soluble components were removed by washing with distilled water until the pH of the washing liquid became neutral. Then, it was washed with 50% acetone water, thoroughly dehydrated with acetone, and dried at 80 ° C. for 24 hours to obtain 13.8 g of colorless and transparent bead-shaped β-cyclodextrin polymer.

Example 100 g of medium-sized regular coffee was leached with 1.5 liters of hot water by a paper drip method to obtain a coffee extract. To this coffee extract, 30 g of the cyclodextrin polymer obtained in Production Example was added and stirred for 20 minutes. After leaving still for a while, the coffee extract was transferred to a decanter. Changes in the amounts of chlorogenic acid and caffeine in the coffee extract before and after the adsorption treatment were measured by high performance liquid chromatography (HPLC), and a sensory evaluation test was also performed. The measurement results and the evaluation test results are shown in Tables 1 and 2.

HPLC measurement conditions Model: Shimadzu LC-6A Column: BIO-RAD ODS-5S, 250 × 4
mm (reverse phase column) Mobile phase: (5-40%) acetonitrile / 0.1% K ₃
PO ₄ flow rate: 1 ml / min Detection: UV 280 nm, 30 ° C.

Table 1 Caffeine content Chlorogenic acid content Before adsorption treatment 512 ppm 655 ppm After adsorption treatment 501 ppm 123 ppm Reduction amount 11 ppm 532 ppm Removal rate 2.1% 81.2%

The taste of the coffee extract after the adsorption treatment was compared with that before the adsorption treatment and evaluated in the following 5 grades. In addition,
This sensory evaluation test was carried out by 20 panelists. Table 2 Number of evaluated people Tasty 15 Slightly tasty 5 No change 0 Slightly bad 0 Poor 0 All the panelists evaluated that the taste of the coffee extract after the adsorption treatment was improved.

Comparative Example Cyclodextrin polymer and polyamide resin (trade name: Polyamide-C200, manufactured by Wako Pure Chemical Industries, Ltd.) were added to 50 ml of a 2000 ppm chlorogenic acid aqueous solution, respectively.
g and stirred for 20 minutes. Then, centrifuge to reduce the amount of chlorogenic acid in the supernatant by measuring the absorbance (A
₃₂₄ ) and compared the adsorption amount of chlorogenic acid by the cyclodextrin polymer and the polyamide, the adsorption amount by the cyclodextrin polymer was 83.2.
The amount adsorbed on the polyamide resin is 40.3 mg.
Met.

After the adsorption treatment, an attempt was made to regenerate the cyclodextrin polymer and the polyamide resin. The cyclodextrin polymer was rapidly separated from the sample solution by spontaneous precipitation, and the sample solution could be easily obtained by decantation. The isolated cyclodextrin polymer is
By repeating the washing with stirring and decantation several times using an ethanol solution, the adsorbed chlorogenic acid was almost completely recovered and the cyclodextrin polymer was regenerated.

The polyamide resin had a poor sedimentation property and could not be easily separated from the sample solution. 1 at 3000 rpm
Even if it was centrifuged for 0 minutes, it did not settle sufficiently and the polyamide resin immediately floated, so that a simple regeneration operation such as cyclodextrin polymer could not be adopted.

[0023]

Industrial Applicability According to the present invention, there is provided a method for improving the taste of a coffee extract capable of easily and efficiently removing chlorogenic acid, which is an unpleasant bitter component in the coffee extract.
Further, according to the present invention, since the cyclodextrin polymer is easily recovered and regenerated, a method for improving the taste of a coffee extract, which can improve the taste simply and at low cost, is provided. The present invention further provides a highly safe method for improving the taste of a coffee extract.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Tsuchiyama 4-12-1, Shonandai, Fujisawa-shi, Kanagawa 2-213 Yen-housing (72) Inventor Hiroshi Tsunekawa 3-13-1, 401 Hatori, Fujisawa-shi, Kanagawa (72) Inventor Kazuhiko Okamura 2502-1 Fujisawa, Fujisawa-shi, Kanagawa 2502-1 (72) Inventor Rokuro Okamoto 2-18 Hananoki, Fujisawa-shi, Kanagawa (72) Inventor Kazuaki Harada 4-424, 305 Matsushiro, Tsukuba, Ibaraki

Claims (2)

[Claims] 1. A method for improving the taste of a coffee extract, which comprises contacting a coffee extract with a cyclodextrin polymer and adsorbing and removing chlorogenic acid in the extract by the cyclodextrin polymer. 2. The method for improving the taste of a coffee extract according to claim 1, wherein the cyclodextrin polymer is water-insoluble and in a crushed state or a beaded state.