JP2995274B2 - Method for improving the taste of coffee extract - Google Patents

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 from 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 and has a mild bitter taste that does not remain. Chlorogenic acid is hardly soluble in water and exhibits bitterness, acidity, and astringency. If this chlorogenic acid is present more than necessary in the coffee extract, the coffee extract not only exhibits a sour and severe bitter taste, but also causes haze and precipitates during storage.

Conventionally, a method of adding a water-soluble cyclodextrin to drinking water to mask glycosides having a bitter taste such as chlorogenic acid (Japanese Patent Publication No. 59-31679), a method of converting chlorogenic acid into a synthetic resin Kaisho 62-615
No. 69) or ceramics (Japanese Patent Laid-Open No. 1-22).
No. 8447) has proposed a method for adsorption and removal.

[0004]

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

In the case of the 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 would.

Some synthetic resins, for example, polyvinylpyrrolidone resin, polyethylene resin, polyamide resin, etc., have a selective adsorption property to chlorogenic acid, but all have a problem in safety. In addition, there is a problem that the amount of adsorption is small or there is a problem in operability.

[0007]

SUMMARY OF THE INVENTION 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 accomplished by finding that a water-insoluble cyclodextrin polymer selectively adsorbs chlorogenic acid in a coffee extract. The cyclodextrin polymer used in the present invention not only has a high ability to selectively adsorb chlorogenic acid, but also has high safety because it polymerizes cyclodextrin, which is recognized as a natural additive to foods. This has the advantage that the cyclodextrin polymer having adsorbed thereon is easily removed from the coffee extract.

[0009] The contact of the cyclodextrin polymer with the coffee extract is effected by adding an appropriate amount of the cyclodextrin polymer to the coffee extract, for example, 0.1 to the coffee extract.
After adding about 30 parts by weight, the mixture may be adsorbed by stirring, and then removed outside the system. Alternatively, the chlorogenic acid may be removed by passing the coffee extract through a column filled with a cyclodextrin polymer. In general, a space velocity (SV) of 0.5 to 2.0 is preferably adopted as the liquid passing speed.

The cyclodextrin polymer used in the present invention is a polymer composed of α-cyclodextrin, β-cyclodextrin and / or γ-cyclodextrin. Each cyclodextrin has six,
It is a cyclic oligosaccharide in which 7 and 8 glucoses are α-1,4 linked. Cyclodextrin polymers have α
One, two or more of-, β- and γ-cyclodextrin may be a constituent unit.

These water-insoluble cyclodextrin polymers are conventionally known polymers obtained by reacting cyclodextrin with a crosslinking agent such as epichlorohydrin, diepoxy compound, diisocyanate or acrylamide derivative and cyclodextrin. For example,
Japanese Patent Publication No. 60-11961 discloses a method of obtaining an insoluble polymer by dispersing cyclodextrin, which has been polymerized to a degree not to be insolubilized in advance using epichlorohydrin, in liquid paraffin, and adding a crosslinking agent while maintaining a predetermined temperature. JP-A-60-20924 discloses a method of obtaining an insoluble polymer by dispersing and reacting cyclodextrin, which has been polymerized to such an extent that it is not insolubilized in advance by a crosslinking agent, in the crosslinking agent.

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 a bead shape and a crushed shape. The particle size is not particularly limited, but is preferably 300 μm or less from the viewpoint of the strength of the polymer and the like.

[0013] Separation after adding the cyclodextrin polymer to the coffee extract and adsorbing chlorogenic acid is easy even by spontaneous sedimentation. In contrast, polyamide resins, which are the most common synthetic resins reported to selectively adsorb chlorogenic acid, have poor sedimentation properties and require special equipment. In addition, the adsorption amount of chlorogenic acid per unit weight of the cyclodextrin polymer is about twice as high as that of the polyamide resin. The chlorogenic acid adsorbed on the cyclodextrin polymer is easily desorbed with a dilute acid, dilute alkali or ethanol aqueous solution, so that it can be easily regenerated and reused.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to embodiments. In the following examples, parts and% mean parts by weight and% by weight, respectively, unless otherwise specified.

Preparation Examples Preparation of Water-Insoluble Cyclodextrin Polymer Powdered β-cyclodextrin (RINGDEX-
B, manufactured by Mercian Co., Ltd.) and mixed with 10 ml of water and 10 ml of a 50% aqueous sodium hydroxide solution.
And 100 mg of sodium borohydride to obtain a uniform solution. While maintaining this solution at 60 ° C., 30
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. Then, 200 ml of liquid paraffin was added, and the mixture was stirred at a speed of 1,000 rpm for 2 hours. The obtained cyclodextrin polymer 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. Further, it was washed with distilled water until the pH of the washing solution became neutral to remove sodium hydroxide, sodium borohydride and water-soluble components. Then, after washing with 50% acetone water, it was sufficiently dehydrated with acetone, and dried at 80 ° C. for 24 hours to obtain 13.8 g of a colorless and transparent bead-like β-cyclodextrin polymer.

Example 100 g of medium-sized regular coffee was leached with 1.5 liter of hot water by a paper drip method to obtain a coffee extract. 30 g of the cyclodextrin polymer obtained in the production example was added to the coffee extract and stirred for 20 minutes. After standing 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 conducted. Tables 1 and 2 show the measurement results and evaluation test results.

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 Decrease 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 by the following five steps. In addition,
This sensory evaluation test was performed by 20 panelists. Table 2 Evaluated persons delicious 15 slightly delicious 5 unchanged 0 slightly unsatisfactory 0 unsatisfactory 0 All the panelists evaluated that the taste of the coffee extract after the adsorption treatment was improved.

Comparative Example A cyclodextrin polymer and a polyamide resin (trade name: polyamide-C200, manufactured by Wako Pure Chemical Industries, Ltd.) were added to 50 ml of a 2000 ppm aqueous chlorogenic acid solution, respectively.
g was added and stirred for 20 minutes. After that, centrifugation was performed, and the decrease in chlorogenic acid in the supernatant was measured using the ultraviolet absorbance (A
₃₂₄ ), and the amount of chlorogenic acid adsorbed on the cyclodextrin polymer and the polyamide was compared. The amount of adsorption on the cyclodextrin polymer was 83.2.
mg, and 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 quickly separated from the sample solution by spontaneous sedimentation, and the sample solution was easily obtained by decantation. The separated cyclodextrin polymer is
By repeating agitation washing 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 poor sedimentation, and was not easily separated from the sample solution. In addition, 1 at 3000 rpm
Even if it was centrifuged for 0 minutes, the resin did not settle sufficiently and the polyamide resin immediately floated, so that a simple regeneration operation such as a cyclodextrin polymer could not be adopted.

[0023]

According to the present invention, there is provided a method for improving the taste of a coffee extract which can easily and efficiently remove chlorogenic acid, which is an unpleasant bitter component in the coffee extract.
Further, according to the present invention, there is provided a method for improving the taste of a coffee extract, which can easily and inexpensively improve the taste because the cyclodextrin polymer can be easily recovered and regenerated. According to the present invention, there is further provided a method for improving the taste of a coffee extract with high safety.

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Rokuro Okamoto 2-18 Hanaki, Fujisawa-shi, Kanagawa Prefecture (72) Inventor Kazuaki Harada 4-424, Matsushiro 4-chome, 305, Matsushiro, Tsukuba-shi, Ibaraki Prefecture (58) Field surveyed (Int. Cl. ^6, DB name) A23F 5/00 WPI (DIALOG)

Claims (2)

(57) [Claims] 1. A method for improving the taste of a coffee extract, comprising contacting the coffee extract with a cyclodextrin polymer, and adsorbing and removing chlorogenic acid from the extract to the cyclodextrin polymer. 2. The method for improving the taste of a coffee extract according to claim 1, wherein the cyclodextrin polymer is insoluble in water and in a crushed or beaded form.