JPH01211449A - Extraction and separation of coffee oil containing aromatic component - Google Patents

Abstract

PURPOSE:To extract and to obtain a high-quality coffee oil having excellent aroma from roasted coffee, by using carbon dioxide in a subcritical or supercritical state as an extractant. CONSTITUTION:Roasted coffee is blended with preferably 1-75wt.% based on roasted coffee of a polar solvent such as water, propylene glycol or glycerin, preferably water containing an edible substance such as sweetener, inorganic salt for food addition or emulsifying agent for food addition. Then a coffee oil is extracted and separated by using carbon dioxide in a subcritical or supercritical state as an extractant such as carbon dioxide under 50-300kg/cm<2> at 25-70 deg.C.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to subcritical or supercritical carbon dioxide (hereinafter referred to as C
This invention relates to a method for extracting and separating coffee oil having a superior aroma from roasted coffee using O□ as an extraction agent.

The coffee oil obtained according to the present invention can be used in coffee products such as instant coffee and canned coffee with few aromatic components,
Alternatively, it can be added to a variety of other beverages and foods to create high-grade products containing fragrant natural coffee flavor.

(Prior Art) (Problems to be Solved by the Invention) It is known to extract aromatic components from roasted coffee, but the method and problems are as described below.

First, there is a method of obtaining aroma components from roasted coffee at low pressure using steam or inert gas. in this case,
Since only highly volatile aromatic components are extracted,
If you try to use this extract later, most of the aromatic components will be lost and it will not serve as a flavor.

There is also a method of obtaining coffee oil containing aromatic components by pressing using a screw press, etc., but in this method, roasted coffee is processed under high temperature and high pressure conditions during pressing, so chemical changes such as thermal decomposition may occur. and the resulting coffee oil has a low grade aromaticity.

Another method is an extraction method using an organic solvent, but it is difficult to separate the aromatic components from the solvent, and the loss of highly volatile components or residual solvent becomes a major problem.

There are also methods for extracting coffee oil using gaseous COt and liquid COt. These extraction methods can extract aroma components at relatively low pressure, but the solubility is low due to the low temperature, and especially in the case of extraction using liquid COt, it is difficult to separate aroma components during solvent separation.
Requires heating energy.

Furthermore, Japanese Patent Publication No. 51-33185 describes a method for extracting coffee oil using 008 in a supercritical state. However, in this method, as is clear from the examples, C
Unless O8 is used, the desired extraction efficiency cannot be obtained. This is because roasted coffee itself is porous and has adsorption activity for oils and aromatic components. This seems to be because it is difficult to obtain coffee oil containing aromatic components with the desired extraction efficiency using CO□ in a mild supercritical state.

Roasted coffee generally contains about 13% oil, and since the volatile aroma components are originally lipophilic, it is best to obtain them dissolved in coffee oil. This is extremely advantageous because it suppresses dissipation and decomposition, and furthermore, the stability of aroma components is increased due to the antioxidant effect of tocopherol contained in coffee oil.

However, roasted coffee has a porous structure, so-called activated carbon-like structure, due to the evaporation of water contained in the green beans and the carbonization of the green beans themselves, although this varies depending on the roasting method. Because of its adsorption and action, the economically advantageous method of extracting coffee oil using CO-enriched in a mild supercritical state at low pressure and low temperature removes the amount contained in roasted coffee, which is the raw material. Approximately 172% of coffee oil
(5 to 7% of the raw material).

For these reasons, it is impossible to efficiently extract coffee oil containing aromatic components.
In the example of the publication, coffee oil containing aromatic components must be extracted under conditions of considerably high pressure or high temperature to overcome the aromatic components in roasted coffee and the adsorption activity for coffee oil, which is not economically viable. However, it was also disadvantageous in terms of obtaining high-quality aroma components.

(Means for Solving the Problem) In view of the current situation, the present inventors have repeatedly conducted various studies on an economically advantageous and efficient method of extracting coffee oil containing aromatic components from roasted coffee. As a result, we finally arrived at the present invention.

That is, the gist of the present invention is to add a polar solvent to roasted coffee as a raw material in advance, and then add CO in a supercritical state at a relatively low pressure and low temperature (including CO in a subcritical state) as an extraction agent. , an attempt is made to obtain coffee oil containing desired aroma components.

008 in the subcritical or supercritical state is at the critical point (31,0
It has a density close to that of a liquid and a large diffusion coefficient close to that of a gas, and because of these characteristics, it can quickly and in large quantities collect various compounds. It can be extracted efficiently.Moreover, it requires only a small amount of pressure.
It is easy to separate from oil due to temperature changes, and
The unique advantage of CO is that it can be treated at relatively low temperatures in an inert atmosphere, and it is also hygienic as it can be expected to have bacteriostatic or bactericidal effects. Application of this method has been actively attempted, and it is the most suitable extraction method for obtaining coffee oil containing aromatic components, which is the object of the present invention.

However, in the method of extracting coffee oil containing aromatic components using COf in a subcritical or supercritical state using roasted coffee as a raw material, as mentioned above, the adsorption activity of the aromatic components and oils of the roasted coffee itself Therefore, coffee oil can only be extracted under supercritical conditions at high pressure or high temperature.

Therefore, in order to solve the above problem, the present inventors have made extensive studies and found that in order to suppress the adsorption activity of roasted coffee itself for oil, a polar solvent is added and mixed in advance to the roasted coffee as a raw material. By actively adsorbing it and then extracting it using COI in a subcritical or supercritical state, high-quality coffee oil containing the desired aroma components can be obtained efficiently and economically. I found out that it can be done.

The adsorption phenomenon of oil by roasted coffee itself is thought to occur to some extent even when roasted coffee beans are ground, but mainly coffee oil containing aromatic components is extracted from this roasted coffee to a subcritical or supercritical state. This is thought to occur when extracting CO8 as an extractant. This is because when coffee oil is extracted, the oil is once dissolved in CO3 and diffused, increasing the degree of contact with the roasted coffee tissue and promoting adsorption.

Therefore, in order to prevent the adsorption phenomenon that occurs during the extraction of coffee oil, the present inventors added the raw material, roasted coffee, in advance.
A method of adding and mixing a polar solvent was used.

In this case, as the polar solvent, first of all, a hydrophilic solvent is desired, which is recognized as a food additive and poses no food hygiene problem. It is also desired that it is difficult to dissolve in Cot in a subcritical or supercritical state, is easily adsorbed by roasted coffee itself, and is not contained at all in the coffee oil extract.

Polar solvents that meet the above conditions include water, glycerin,
Examples include propylene glycol.

These can be used alone or in combination. Among the above polar solvents, water is most preferably used in terms of safety, handling, cost, etc. Also, depending on the extraction conditions, if a small amount of edible substances such as sweeteners such as glucose and aspartame, inorganic salts for food additives such as sodium chloride and sodium bicarbonate, and emulsifiers for food additives are added,
In some cases, extraction efficiency is improved.

The amount of polar solvent added to roasted coffee varies depending on the type of polar solvent used, but the appropriate amount is 1 to 75% of the weight of roasted coffee as a raw material, and usually 50% or less is sufficient. The purpose of the invention is fully achieved. When a polar solvent is added at a ratio exceeding 75%, the amount exceeds the saturated adsorption amount of roasted coffee, reduces the solubility of coffee oil in COf in a subcritical or supercritical state, and becomes an unfavorable condition for extraction of coffee oil. Become. In addition, if the amount is less than 1%,
No effect of addition was observed.

In general, a polar solvent that is difficult to dissolve in 008 in a subcritical or supercritical state serves to lower the solubility of the extract in 008 depending on its amount.

Figure 1 shows the influence of water on the extraction of fats and oils by supercritical cobalt from soybeans, a typical plant seed.
If the soybean raw material contains 25% water, the extraction rate of soybean oil will be less than 1/3, and if it contains 50% more water, the extraction rate will decrease to about 1/10. I understand. However, in the present invention, even if roasted coffee contains about 50% of a polar solvent such as water, propylene glycol, or glycerin, the extraction rate of coffee oil does not decrease at all, as shown in the examples below, and it is clear that It was confirmed that it was adsorbed into the structure of roasted coffee and had no adverse effect on the extraction rate of coffee oil.

Hereinafter, embodiments of the present invention will be described based on a flow sheet. In Fig. 2, CO8 is compressed from a CO8 cylinder 1 to a predetermined pressure using a compressor 2, is brought to a predetermined extraction temperature through a heat exchanger 3, and is brought to a subcritical or supercritical state and sent to an extraction tower 4. and introduce it. The extraction tower 4 is charged with roasted coffee bean powder mixed with a polar solvent.
After extraction with 0.08, the CO□ phase containing the extract is depressurized through the pressure reducing valve 5 and introduced into the separator 6 to separate the extract from the Co. The CO separated from the extract is cooled and liquefied in a condenser 7, passed through a compressor, and recycled.

In addition, COt is introduced into the extraction tower by increasing the pressure in stages,
Stepwise extraction can also be performed. Furthermore, it is also possible to perform semi-continuous operation by installing a plurality of extraction columns in parallel and switching between them.

Generally, in the process shown in Fig. 2, the extract is separated over time by the separator 6, but as the pressure is gradually lowered, the extract components will differ, so depending on the desired components, can be recovered by changing the preparative method. That is, by providing multiple separators in series,
It is also possible to perform fractional separation and recovery by lowering the pressure in stages.

In addition, when separating extracts over time using a separator,
Since the extract components obtained differ depending on the method of fractionation, it is also possible to perform fractional extraction of the desired component.

(Examples) Hereinafter, the present invention will be explained in more detail by showing Examples, but the present invention is not limited thereto.

Example 1 500 g of ground roasted coffee beans (fat content 13,1
%) as raw material, add 100g of water (20% of raw material)
200 k by the process shown in Figure 2.
Extraction was carried out for 30 g/cd using COt as extractant at 38°C.
The extract was separated at room temperature and atmospheric pressure for 58 g.
Coffee oil containing aromatic components was obtained.

Comparative Examples 1 to 2 As a comparative example, 500 g of the same ground roasted coffee beans as in Example 1 were used as the raw material, and extraction was performed under the same conditions as in Example 1 without adding any water, resulting in 29 g of coffee oil. I could only get it.

In addition, as a comparative example with high extraction pressure and temperature, Example 1
Using 500 g of the same ground roasted coffee beans as the raw material, extraction was performed for 3 hours using 350 kg/C4, CO8 at 150°C as an extraction agent without adding any water, and 46 g of coffee oil was obtained.

Above is Example 1. The coffee oil extraction rate, the lipid content of the extraction residue, and the sensory evaluation of the extracts of Comparative Examples 1 and 2 are shown in Table 1 below.

Table 1 The lipid content is determined by Soxhlet extraction using ether.
I went for 5 hours.

From the results shown in Table 1, it was confirmed that by adding water to the raw material roasted coffee, it was possible to efficiently extract and separate coffee oil of excellent quality.

In addition, these three types of extracts were emulsified using a commercially available emulsifier,
When added to instant coffee and canned coffee, the one using the extract obtained in Example 1 had the best aroma compared to the other two, and also had a deep and rich taste similar to regular coffee. I was able to confirm that this was the case.

This is presumed to be due to the fact that by adding water to the raw material, the water functions to adjust the solvent polarity of COt, making it easier to obtain taste components, which are mainly polar substances, as an extract.

Example 2 Using 800 g of ground roasted coffee beans as a raw material, 320 g of water (40% of the raw material) was added and mixed, and Example 1
Extraction was carried out for 3 hours under the same conditions as above, and the extract was separated at room temperature and atmospheric pressure to obtain 89 g of coffee oil containing aroma components.

This coffee oil was equivalent to that obtained in Example 1, and had a high quality and deep aroma.

Further, the extraction rate of the coffee oil obtained here with respect to the weight of the raw material was 11.1%, and this result was also the same as in Example 1.

Example 3 Using 1000g of ground roasted coffee beans as a raw material, 200g of propylene glycol (20% of the raw material) was added and mixed, and the process shown in Figure 2 was carried out to produce 190kg/c.
d. Extraction was carried out using Co as an extractant at 40°C for 3 hours,
The extract was separated at room temperature and atmospheric pressure to obtain 108 g of coffee oil containing aroma components.

This coffee oil was equivalent to that obtained in Example 1.2 and was of excellent quality. In addition, the extraction rate of the coffee oil obtained here based on the weight of the raw material was 10.8%.
This result is also similar to Example 1.2.

Example 4 500 g of ground roasted coffee beans were used as a raw material, 150 g of water (30% of the raw material) was added thereto, mixed, and heated to 150 kg/cm2 at 39°C in the process shown in Figure 2.
Extraction was performed for 3 hours using Ot as an extractant, and the extract was separated at room temperature and atmospheric pressure to obtain 42 g of coffee oil containing aromatic components.

Comparative Example 3 In addition, using 500 g of the same raw material as in Example 4, extraction was performed for 3 hours under the same conditions as in Example 4 without adding any water, and the extract was separated at room temperature and atmospheric pressure to yield 26 g. Coffee oil containing aromatic components was obtained.

The results of Example 4 and Comparative Example 3 are summarized in Table 2.

Table 2 Even when extracting coffee oil under relatively low pressure and temperature conditions, adding water allows efficient extraction, and the resulting coffee oil has extremely excellent aromatic properties. It was also found that the concentration of aroma components was high.

On the other hand, the roasted coffee bean extract residue in Comparative Example 3 contained a considerable amount of lipids and high-quality aromatic components, confirming the effect of water addition.

Example 5 Using 1000 g of ground roasted coffee beans as a raw material, 200 g of glycerin (20% of the raw material) was added and mixed, and in the process shown in Figure 2, 180 kg/cd, 39
Extraction was performed for 3 hours using Cot at °C as an extractant, and the extract was separated at room temperature and atmospheric pressure to obtain 113 g of coffee oil containing aromatic components.

The extraction rate and quality of this coffee oil based on the weight of the raw material are equivalent to those obtained in Examples 1, 2, and 3, and the purpose of the present invention can be sufficiently achieved even by adding glycerin. was confirmed.

Example 6 100 g of an aqueous solution prepared by mixing 500 g of ground roasted coffee beans with water and glycerin at a ratio of 1:1.
(20% based on the raw materials) was added and mixed, and extraction was performed for 3 hours using COz at 180 kg/cm2 and 40''C as an extractant in the process shown in Figure 2, and the extract was separated at room temperature and atmospheric pressure. Thus, 55 g of coffee oil containing aroma components was obtained.

The coffee oil obtained here is also of high quality and has a strong aroma, and
The extraction rate was also 11.0 relative to the raw material, and it was found that coffee oil with a strong aroma can be extracted efficiently even when a mixed solvent of water and glycerin is used.

Example 7 500g of ground roasted coffee beans was used as a raw material, and 2
% sodium chloride aqueous solution (20% based on raw materials) was added and mixed, and in the process shown in Figure 2, 130 kg
/cm2, 33°C Cot was used as an extractant for 3 hours, and the extract was separated at room temperature and atmospheric pressure to obtain 40 g of coffee oil with a strong aroma.

Comparative Example 4 As a comparative example, using 500 g of the same ground roasted coffee beans as used in Example 7 as a raw material, extraction was carried out for 3 hours under the same conditions as in Example 7 without adding an aqueous sodium chloride solution. The extract was separated at room temperature and atmospheric pressure to obtain 22g of coffee oil.The results of 6 or more are summarized in Table 3.

Table 3 From these results, the effect of adding 2% sodium chloride is clear.

(Effects of the Invention) According to the present invention, coffee oil having an excellent aroma can be obtained from roasted coffee in an industrially advantageous manner, and the following excellent effects can be achieved compared to conventional methods.

(1) Conventionally, a polar solvent is added to roasted coffee and mixed,
There is no example of extracting coffee oil containing aromatic components using COz in a subcritical or supercritical state as an extracting agent, and the ability to easily and efficiently extract high-grade coffee oil using the present invention is an exciting prospect. That's true.

(2) Since it can be extracted at a relatively low temperature and in an inert atmosphere, there is no risk of deterioration.

(3) Since the C08 used as an extractant evaporates rapidly during the separation process, there is no need to separate the solvent and extract unlike when an organic solvent is used as an extractant.

(4) Compared to conventional extraction methods, it is possible to use CO8 in a subcritical or supercritical state under relatively low pressure and low temperature conditions as an extraction agent, so it is possible to retain the original aroma of roasted coffee, which is the raw material. Can be extracted and obtained without decomposition or dissipation.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the influence of moisture on soybean oil extraction using supercritical 008 as an oil agent, and FIG. 2 is a flow sheet showing an example of an embodiment of the present invention.

Claims (8)

[Claims] (1) When extracting and separating coffee oil containing aromatic components from roasted coffee, a polar solvent is added and mixed to the roasted coffee in advance, and then carbon dioxide in a subcritical or supercritical state is used as an extraction agent. A method for extracting and separating coffee oil containing aromatic components. (2) The amount of polar solvent added is 1 to 7 to roasted coffee.
5% by weight. (3) The method according to claim (1), wherein the polar solvent is at least one selected from the group consisting of water, propylene glycol, and glycerin. (4) The method according to claim (1), wherein the polar solvent is water with an edible substance added thereto. (5) Claim (4) in which the edible substance is a sweetener
Method described. (6) The method according to claim (4), wherein the edible substance is an inorganic salt for food additives. (7) The method according to claim (4), wherein the edible substance is an emulsifier for food additives. (8) Subcritical or supercritical carbon dioxide has a pressure of 5
The method according to claim (1), wherein the temperature is 0 to 300 kg/cm^2 and 25 to 70°C.