JPS60203144A - Flavor improvement in coffee extract - Google Patents

Abstract

PURPOSE:Coffee extract is combined with hydrolase for hydroxycinnamic acid ester to reduce chlorogenic acid and pH in specific ranges to prevent from deterioration of flavor of the extract. CONSTITUTION:The hydrolase for hydroxycinnamic acid ester is allowed to act on coffee extract to remove more than 30% of chlorogenic acid in the extract and lower the pH by less than 0.5, then the enzyme is deactivated by treating the extract, e.g., at a temperature over 65 deg.C for 2sec-20min.

Description

[Detailed Description of the Invention] -Reduces the bitterness derived from chlorogenic acid in coffee extracts and the unrefreshing sourness associated with astringency, and also lowers the pH of coffee extract to prevent deterioration of aroma. It relates to a method for preventing and significantly improving the flavor thereof.

Coffee is an aromatic beverage originally obtained by roasting and crushing the seeds of coffee trees (coffee beans) and extracting them with hot water, and is widely familiar to everyone, but recently it has become more popular. Because of its simplicity, coffee extracts (solful coffee) are available on the market in various forms, including straight (canned coffee), paste, powder, and granules (instant coffee).

These products, i.e., coffee extracts, are usually extracted and prepared from relatively inexpensive low-grade coffee beans such as Robusta, or from higher-grade Arabica coffee beans. The coffee extract obtained in this way is prepared by extremely increasing the extraction rate in cases such as when
It is known that the high acid content of chlorogenic acid results in an unrefreshing sour taste with bitterness and astringency derived from this component, which is a drawback in terms of quality.

Conventionally, methods for removing chlorogenic acid to overcome this drawback in coffee extract include (1) extracting coffee beans with an organic solvent, (2) increasing the degree of roasting of coffee beans, Methods such as bringing a selective adsorbent of chlorogenic acid into contact with a +311-hi extract are known, but first, method (1) poses food safety problems due to residual organic solvents. There is the problem of increased cost burden due to the use of organic solvents, and when method (2) is used, not only is the removal of chlorogenic acid incomplete, but also there is an excessive burnt odor and secondary flavor due to an increase in the pH of the coffee extract. There is a problem with deterioration, and when method (3) is used, there are still problems such as the pH of the coffee extract increasing and the flavor deteriorating, so it is difficult to say that either method is fully satisfactory. .

The present inventors had previously invented a hydrolyzing enzyme for hydroxycinamic acid ester containing chlorogenic acid and a method for producing the same (Japanese Patent Application Laid-open No. 7-7-TATA/RI 3). It is possible to significantly reduce the chlorogenic acid content of coffee extract by adding it to or bringing it into contact with it, and at the same time, it is possible to reduce the pH of the coffee extract, and as a result, The present invention was completed based on the new discovery that the flavor of coffee extract can be significantly improved.

That is, the present invention allows hydroxycinamic acid ester hydrolase to act on coffee extract, and first, the removal rate of chlorogenic acid in the coffee extract is 30 or more, and the pH reduction range is less than or equal to Oj. This is a method for improving the flavor of coffee, which is characterized by stopping enzyme action.

The present invention will be explained in detail below.

The coffee extract used in the present invention is obtained by roasting coffee beans (green coffee) by a conventional method, coarsely grinding, and then extracting with warm water, which is then concentrated or dried to form a paste. Although powdered and granular forms are also included, in the present invention it is appropriate to use them in liquid form.

Coffee beans (green coffee), which is the raw material for this coffee extract, are the seeds of the fruit of the coffee tree, and there are various cultivars such as Asivica, Robusta, and Liberica. Many brands are known.

The coffee extract used in the present invention can be prepared using any of these varieties or brands of coffee beans as a raw material, and in particular, low-grade Robusta 1Ili active coffee beans, which are said to have a high content of chlorogenic acid, can be used. Even better effects can be obtained by applying the method of the present invention to coffee beans prepared using coffee beans as raw materials.

When roasting coffee beans, the higher the chlorogenic acid content, the more dust-free the beans tend to be in order to reduce the chlorogenic acid content. It is usually undesirable because it gives off a strong burnt odor.

However, according to the method of the present invention, the content of chlorogenic acid can be reduced after obtaining the coffee extract in advance, so the degree of roasting can be adjusted without considering the chlorogenic acid content of the coffee extract. Excessive roasting can be avoided and appropriate conditions can be selected and applied for coloring and numbering.

On the other hand, when roasted coffee beans are coarsely ground and extracted with hot water, the processing conditions are usually such that the particle size after coarsely grinding is In reality, strict consideration is given to the temperature of hot water, extraction method, etc., but in the case of the present invention,
Apart from consideration for aroma loss and flavor deterioration due to oxidation, consideration for excessive elution of chlorogenic acid, etc. is 1.
It becomes unnecessary for the reason stated in item 11, and therefore it is possible to extract with an extremely high extraction rate and increase the yield.

In the present invention, a hydroxynonamic acid ester hydrolase is allowed to act on the coffee extract obtained as described above.

The hydroxycinamic acid ester hydrolase used in the present invention has already been disclosed in detail by the present inventors in JP-A-7-TATA/RI3, and includes Aspergillus soya IAM2678 and Aspergillus niger IAM3002. ．． Aspergillus jabonicus A
T CC20236, ill Trince Cinerea FER
A strain such as M-P Al 612 is cultured in solid or liquid culture according to the side method using a medium used for culturing these filamentous fungi, and the aqueous extract or culture solution of the culture is clarified by filtration, and then ammonium sulfate is added. A precipitate is obtained by a salting-out method or an alcohol precipitation method, which is dried to obtain a crude enzyme powder, and if necessary, after dissolving this crude enzyme powder in a buffer solution or the like, DEAE-Sephadex A-50 is added.
, a gel filtration method using ion exchange Sephadex such as QAE-Sephadex A-50 or CM-Sephadex or Sephadex such as Sephadex G-200;
Purified enzymes are prepared by using individual methods such as isoelectric focusing using ampholine, electrophoresis using acetate membrane starch, acrylamide gel, and other isoelectric focusing precipitation methods, or appropriate combinations thereof. Each of these can be used in the present invention.

In this case, it is more advantageous from an economic point of view to use crude enzyme powder or the minimum necessary amount of purified enzyme, and in order to further increase the economic efficiency of the enzyme, it is immobilized by a conventional method and used as an immobilized enzyme. It can also be used for inventions.

As for the method of adding the above-mentioned enzyme to coffee extract or bringing it into contact with it to make it act, since the present invention reduces the chlorogenic acid content of coffee extract by enzyme action, the coffee extract is in a liquid state. Specifically, in the case of liquid coffee extract such as hot water extract of roasted and coarsely ground coffee beans, it is suitable to be used as is, or in the form of paste, powder, granules, etc. In the case of coffee extract, it is dissolved in warm water to a concentration of ~30% by weight to make it liquid, and then the above-mentioned enzyme is added to this, or the above-mentioned enzyme is immobilized by a conventional method. Removal rate of at least 30
% or more, it is important to stop the enzyme action within the pH range of at least O2j or below.

That is, the present invention provides chlorogenic acid in coffee extract,
For example, chlorogenic acid is removed by hydrolyzing 3-cafnioylquinic acid by hydroxycinamic acid ester hydrolase, and at this time, the pH of the coffee extract is low.Here, it is used as drinking coffee. Not only does bitterness and astringency disappear, but the deterioration of aroma can also be prevented.

The present inventors investigated in more detail the conditions for removing chlorogenic acid by the enzyme action of the present invention, and found that the removal rate of chlorogenic acid in coffee extract was at least 30%.
% or more, and when the enzyme reaction is stopped at a low pH range of at least 0.3 or less, products with excellent flavor can be obtained.

If the pH of the coffee extract drops too much, the acidity will increase and the flavor balance will be disrupted, making it impossible to enjoy a desirable coffee extract.

In order to stop the enzyme action, it is common to heat-inactivate the enzyme in the coffee extract. may be heated at 65° C. or higher for 1 second to 20 minutes by selecting conditions necessary for heat inactivation of the enzyme.

Next, the effects of the present invention will be explained using experimental examples.

Experimental Example 1 Sprinkle water from the SOO meter on the wrinkles of 2002, and after steaming for 30 minutes in an autoclave at atmospheric pressure, Aspergillus.
Japonicas AT CC20236 was completely inoculated and cultured at 30°C for ≠ days. Add 1/l of water to the koji obtained in this way, stir at room temperature for 2 hours, filter through cotton cloth, add celite to the mixture, filter again with f1 yellowing, and extract the transparent koji. A liquid was obtained.

This extract/l was subjected to ultrafiltration (filtration membrane XM manufactured by Amicon).
-5,0 used) to concentrate to 200 ml, and while cooling this concentrate, gradually add 00 ml of cold ethanol to precipitate the enzyme fraction.The precipitate was collected by centrifugation, and freeze-dried. 3. Dry to obtain crude enzyme powder.
22 was obtained.

Hydroxycinamic acid ester hydrolase activity of the crude enzyme powder was determined by the method of Mazuma et al. using 3-cafnioylquinic acid as a substrate.
Chemistry Vol. 46, p. 297, (/ri82)] As a result of measurement, the enzyme activity was able to hydrolyze 10.2 units/V enzyme (/unit is/) zmol of 3-cafnioylquinic acid in 7 minutes. )Met.

Next, commercially available soluble instant coffee /22 /,
Dissolve in 2 tons of hot water, divide into 20 orue sections, and add 30 Tnq of the above crude enzyme powder to the evening section excluding the control section.
/, Oa13 were dissolved in water and added, and allowed to react at ≠θ°C for the time shown in Table 1. The enzyme was deactivated by heat treatment at 70°C for 10 minutes to stop the enzyme action.

The oogenic acid content and pH of the samples of each category thus obtained were measured, and a sensory plan for palatability was conducted by a panel of seven people, and the results shown in Table 1 were obtained.

* The chlorogenic acid content was determined by high-performance liquid chromatography using occudecyl silica as a separation resin, applying the method of Ryouso et al. [Agricultural Biological Chemistry Vol. It was measured using

Experimental Example 2 After roasting, coarsely ground Brazilian Xantos coffee (roasting color, to) stty was extracted with 7300 ml of distilled water using a normal bar colleter to obtain 200 rnl of liquid coffee extract. It was done.

This was divided into 200 mli sections, and the crude enzyme powder prepared in Experimental Example 1 was divided into 5 sections, excluding the control section.

My/Ome was dissolved in water and added, and the mixture was allowed to react at 50°C for the time shown in Table 2. The enzyme was heat-inactivated by heat treatment at yo°C for 7 minutes to stop the enzyme action. For the samples of each category obtained in this way, the chlorogenic acid content and pH were measured in the same manner as in Experimental Example 1,
Sensuality tF Iil regarding palatability by a panel of 7 people
[The results in Table 2 were obtained by adding i.

From the results in Tables 1 and 2, it can be seen that by allowing the hydroxycinnamic acid ester hydrolase to act on coffee extract, the pH will be lowered by the amount of chlorogenic acid in the coffee extract. In relation to the plan, the removal rate of chlorogenic acid in coffee extract is 30% or more, and the pH reduction range is 0. It can be seen that the flavor of the coffee extract is significantly improved when the enzyme is thermally inactivated by heating and the enzyme action is stopped.

As described above, the present invention is an unprecedented method for removing chlorogenic acid from coffee extract using an enzymatic method, and unlike conventional methods, it does not raise the pH of coffee extract, but rather requires it. As a result, the flavor of low-quality coffee extracts with high chlorogenic acid content can be significantly improved.

Example Paranas coffee Otsu Q Kf coarsely ground after roasting 20K
Divide into 3 sections of 3 g each, put the first 20 kg in a percolator and extract with hot water at g℃≠01 for 20 minutes, use this extract to extract the next 20 kg in the same way, and then Using the extract, extract the final 2θ to 9 and finally make a coffee extract with a Brix of 2J degrees to 30
I got 1.

The chlorogenic acid content and pH of this coffee extract were measured in the same manner as in Experimental Example 1, and were found to be 2.
1. Y/l and tough 3.

Next, the temperature of this coffee extract was adjusted to 50°C, and 0.12% of crude enzyme powder j22 of hydroxycinamic acid ester hydrolase prepared by the method described in Experimental Example 1 was added to it.
The chlorogenic acid content and pHi of the coffee extract were measured in the same manner as in Experimental Example 1, and the chlorogenic acid content and pHi of the coffee extract were measured in the same manner as in Experimental Example 1. The coffee extract was introduced into a spray dryer that sent hot air at 730°C to simultaneously stop the enzyme action and dry the coffee powder, yielding 6.7K9 coffee powder.

The coffee obtained by dissolving this coffee powder/k/00 rye in boiling water was of excellent quality with little bitterness, good balance with acidity, and good aroma.

Patent applicant: Kisokoman Co., Ltd.

Claims (1)

[Claims] +ll A hydroxycinamic acid ester hydrolase is applied to the coffee extract, and the removal rate of chlorogenic acid in the coffee extract is 30% or more, and the pH is low.
The range is 0. A method for improving the flavor of coffee extract, which is characterized by ceasing enzymatic action at a temperature below 50°C.