JPH0128800B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for extracting citrus essential oil, which can industrially advantageously produce citrus essential oil with excellent aroma and flavor easily and in a shortened processing time.

More specifically, the present invention provides for freezing and pulverizing the peel or juice residue of citrus fruits such as yuzu, oranges, lemons, and grapefruits under temperature conditions of 10° C. or lower and at which the frozen state of the pulverized product is not substantially lost. The present invention relates below to a method for extracting citrus essential oil, which is characterized by extracting with a poorly water-miscible to water-immiscible organic solvent and distilling off the solvent from the extract at a temperature of 50° C. or lower.

Conventionally, citrus essential oils such as yuzu oil, orange oil, lemon oil, grapefruit oil, etc., have generally been produced by the Motsupara oil extraction method. The reason for this is that citrus essential oils are easily altered by heat, light, oxygen, etc., so if steam distillation or heated extraction methods using solvents are used, it is difficult to avoid flavor alteration and it is difficult to obtain essential oils with a satisfactory flavor. This is because the adoption of the extraction method tends to involve excessive extraction of naringin-containing bitter components and other undesirable extraneous components, making it difficult to obtain essential oils of good quality. On the other hand, with the oil extraction method, there is little risk of flavor deterioration, but it requires the use of an expensive press, and it also has the disadvantages of equipment and operation that require high oil extraction pressure. Depending on the form of the raw material, there is a disadvantage that an additional operation is required to separate the essential oil from the extracted product.

Therefore, in order to employ an easy-to-operate extraction method and avoid flavor deterioration, cold extraction or cold immersion methods may be considered. However, the use of cold conditions is expected to have the disadvantage of prolonging the extraction or leaching time. Furthermore, during this long extraction or leaching operation, flavor deterioration is inevitable unless cold conditions are maintained, so there is a drawback that cold conditions must be maintained for a long time, for example, 24 hours or more. Furthermore, such long-term extraction or leaching has the drawback of excessive extraction or leaching of undesirable impurities; It is expected that there will be many technical defects, such as problems such as flavor deterioration during removal. Since such expectations have been a common practice among those skilled in the art, the reality is that the Motsupara oil extraction method has hitherto been adopted industrially.

The present inventors have conducted research to develop a satisfactory extraction method for citrus essential oil.

As a result, the frozen pulverized product obtained by pulverizing frozen citrus peel or citrus juice residue was heated at 10°C.
Contrary to the above expectations, by extracting with a poorly water-miscible to water-immiscible organic solvent under a temperature condition in which the frozen state of the pulverized product is not substantially lost, , with a significantly shortened extraction time (usually about 2 hours or less), citrus essential oils of excellent quality without excessive extraction of undesirable extraneous components and with excellent aroma and flavor without any problem of flavor deterioration can be extracted efficiently. It was discovered that extraction can be performed well and in high yield.

Furthermore, the extract obtained in this way is capable of distilling off the solvent from the extract at a low temperature of 50°C or lower, preferably 40°C or lower, without causing undue inconvenience. It has been discovered that it is possible to obtain a citrus essential oil of excellent quality that does not contain any extraneous components, has no problem of deterioration, and has an excellent aroma and flavor.

Therefore, an object of the present invention is to provide an industrially advantageous extraction method for citrus essential oils.

The above objects and many other objects and advantages of the present invention will become more apparent from the following description.

The frozen pulverized product of peel or juice residue of citrus fruits such as yuzu, orange, lemon, grapefruit, etc. used in the present invention is a frozen product obtained by freezing the peel or juice residue at a low temperature such as -20°C or lower. can be obtained by pulverizing with a suitable pulverizer, preferably a freeze pulverizer that can be cooled to -20°C or lower. In particular, at low temperatures such as -20°C or lower, the cell membranes of citrus peels or juice residue become fragile, and as a result, the pulverization is performed more effectively using a pulverizer, resulting in a higher extraction rate of essential oils than conventional pulverization at room temperature. Freeze-grinding is preferred as it significantly improves the quality.

According to one aspect of the present invention, during the extraction treatment operation of the frozen pulverized material, temperature conditions are employed in which the frozen state of the pulverized material is not substantially lost, but any low temperature conditions of 10° C. or lower are employed. can do. It is presumed that this is because the essential oil components contained in the frozen pulverized material are present in the pulverized material in a state where they can be easily separated from the frozen water in the frozen pulverized material. It has been unexpectedly discovered that under temperature conditions where there is no substantial loss, it can be extracted very quickly and without alteration, and also in good yields. Therefore, according to the method of the present invention, the above-mentioned frozen pulverized product of citrus peel or citrus juice residue is mixed with water under a temperature condition of 10° C. or lower and the frozen state of the pulverized product is not substantially lost. Extract with a water-immiscible organic solvent.

Examples of organic solvents to be used include n-pentane, isopentane, n-hexane, benzene, diethyl ether, methylene chloride, methyl ethyl ketone, etc.
-Pentane, isopentane and n-hexane are more preferred. The amount of solvent used can be selected as appropriate, for example, about 0.5
For example, the amount used may be 20 to about 20 times the weight.

The extraction is carried out under low temperature conditions of 10°C or lower, for example -10°C to +10°C, more preferably -5°C to +5°C.
Examples include extraction temperatures such as °C. The extraction is carried out under temperature conditions in which the frozen state of the frozen and ground raw material is not substantially lost. Under conditions where the frozen state of the frozen ground raw material is not substantially lost, the water contained in the frozen ground raw material is frozen, so even with strong stirring during the extraction process, the pectin and Since no emulsion is formed even when the extraction solvents are mixed, a transparent extract can be obtained in good yield. The temperature condition where the frozen state of such frozen ground material is not substantially lost is preferably, for example, 0°C or lower, but even at a temperature of 0°C or higher, it seems that the frozen state is maintained within the extraction time. It doesn't matter if you have it.

In addition, using an extraction temperature higher than 10°C is likely to cause the flavor of the citrus essential oil to deteriorate, and at temperatures higher than 10°C, the frozen state of the raw material is virtually lost, so under stirring conditions, emulsions are formed and significant This not only reduces the yield but also interferes with the separation of the solvent. Furthermore, because naringin and the like are extracted excessively and cloudiness is likely to occur, an extraction temperature of 10°C or lower is used.

In order to carry out the extraction treatment under the above-mentioned low temperature conditions of 10°C or less and at a temperature where the frozen state of the frozen ground material is not substantially lost, if desired, the organic extraction solvent to be used may be The extraction process can be carried out by cooling the material to 10° C. or lower, preferably 5° C. or lower, before it comes into contact with the pulverized raw material.

Under temperature conditions where the frozen state of the frozen and ground raw material is not substantially lost, essential oils can be efficiently extracted with short-time stirring. On the other hand, extraction treatment under static conditions requires long immersion because the contact efficiency with the solvent decreases, and therefore it is preferable to perform extraction under stirring conditions. The extraction time can be selected as appropriate. For example, in extraction under stirring conditions, sufficient extraction can be achieved with an extraction time of about 3 hours or less, usually about 2 hours or less, for example about 20 minutes to about 3 hours.

In any case, according to the method of the present invention, contrary to what was previously expected, the extraction time is significantly shortened, resulting in a change in the flavor of the essential oil and excessive extraction of bitter components and other undesirable components. Citrus essential oils with outstanding flavor can be easily extracted in good yields and efficiently without any problems and also while avoiding the formation of undesirable emulsion systems.

According to the method of the present invention, by distilling off the organic extraction solvent from the extract obtained as described above at a temperature of 50°C or lower, a significantly superior flavor can be obtained without any flavor deterioration. You can get citrus essential oil.

After the above extraction operation, insoluble solids are separated and removed using any solid-liquid separation means such as filtration or centrifugation, and if desired, the resulting extract is dehydrated, for example, by adding mirabilite to the extract. After dehydration treatment, the organic extraction solvent is distilled off from the extract at a temperature of 50° C. or lower, preferably 40° C. or lower, at atmospheric pressure to reduced pressure. The reduced pressure conditions can be determined by appropriately selecting the degree of reduced pressure such that the solvent used is distilled off under the above temperature conditions. Adoption of temperature conditions exceeding 50°C should be avoided as it will cause flavor deterioration of the essential oil.

The citrus oil obtained by the method of the present invention as described above can be used in beverages such as fruit juice drinks, non-fruit juice drinks, carbonated drinks, milk drinks, etc.; frozen desserts such as ice cream, sherbet, ice candy, ice milk, etc. It is widely used as a flavor imparting or modulating agent for foods and beverages such as candy, drops, jellies, thiokolate, biscuits, etc.; seasonings; various instant beverages; as well as pharmaceuticals, cosmetics, etc. be able to.

Several embodiments of the method of the present invention will be described in detail in the following examples.

Example 1 After storing 1 kg of yuzu peel at -20°C and freezing,
It was pulverized using a pulverizer. Next, this is heated to 0° to 5°C in advance.
1.5 kg of cooled n-hexane was added thereto, and after stirring and extraction at 5° C. for 1 hour, the mixture was centrifuged to remove insoluble solids.

Next, 0.2% weight of anhydrous Glauber's salt was added to the obtained extract for dehydration, filtration, and the solvent was removed at 30° C. under reduced pressure to obtain 6 g of yuzu oil.

Example 2 1 kg of yuzu residue after juice was stored at -20°C, frozen, and then ground using a grinder. Next, 3 kg of n-hexane previously cooled to -5 to 0°C was added thereto, and after stirring and extraction at -5 to 0°C for 2 hours, the mixture was centrifuged to remove insoluble solids.

Then, the solvent was distilled off from the obtained extract under reduced pressure at 35°C to obtain 4 g of yuzu oil.

Comparative Example 1 Extraction was performed at room temperature for 24 hours using n-hexane at room temperature, and 4 g of yuzu oil was obtained in the same manner as in Example 1, except that n-hexane was distilled off at 60°C under reduced pressure.
I got it.

Comparative test:- The essential oil of Example 1 and the essential oil of Comparative Example 1 above were
When 0.1% of each was added and dissolved in edible oil and fat and sensory evaluated by 10 sensory examiners, the essential oil of Example 1 had a fragrance reminiscent of the peel of a fresh fruit, whereas the essential oil of Comparative Example 1 All noted that the oxidation odor was somewhat reduced, with a lack of light lead aroma.

Example 3 2 kg of lemon peel was stored at -25°C, frozen, and then ground using a grinder. Next, set this in advance to 0°~
Add 3 kg of n-hexane cooled to 3°C and heat to 3°~
After stirring and extraction at 5° C. for 1.5 hours, the mixture was centrifuged to remove insoluble solids.

Next, 0.3% weight of anhydrous Glauber's salt was added to the obtained extract for dehydration, filtration, and the solvent was removed at 30° C. under reduced pressure to obtain 20 g of lemon oil.

Comparative Example 2 19 g of lemon oil was extracted in the same manner as in Example 3, except that extraction was performed at room temperature for 24 hours using n-hexane at room temperature, and n-hexane was distilled off at 60°C under reduced pressure. Obtained.

Comparative test: - The essential oil of Example 3 and the essential oil of Comparative Example 2 above were added and dissolved in edible fats and oils at 0.1%, and sensory evaluation was performed by 10 sensory examiners. While the essential oil of Comparative Example 2 had a scent reminiscent of lemon fruit, all participants observed that the essential oil of Comparative Example 2 lacked a light leading aroma, and that the oxidized odor was somewhat reduced.

Comparative Example 3 1 kg of yuzu peel was stored at -20°C, frozen, and then ground using a grinder. Then n-hexane at 25℃
1.5 kg was added and extracted with stirring at 20°C for 1 hour. Since some emulsion was formed during stirring and extraction, which made centrifugation difficult, insoluble solids were removed by decantation to obtain 900 g of extract.

Next, 0.2% weight of anhydrous sodium sulfate was added to the obtained extract, and after dehydration filtration, the solvent was removed at 30° C. under reduced pressure to obtain 3.2 g of yuzu oil.

Comparative Example 4 1 kg of yuzu residue after juice was stored at -20°C, frozen, and then ground in a grinder.
Add 3 kg of n-hexane cooled to 5-0℃ and -
After stirring and extraction at 5 to 0°C for 2 hours, the mixture was centrifuged to remove insoluble solids.

Then, the solvent was distilled off from the obtained extract under reduced pressure at 60°C to obtain 4 g of yuzu oil.

Comparative test The essential oils of Examples 1 and 2 and the essential oils of Comparative Examples 3 and 4 above were added and dissolved in edible oils and fats at 0.1% and sensory evaluated by 10 sensory examiners. The essential oil of Comparative Example 3 had a fragrance reminiscent of fresh yuzu peel.
The essential oil of Comparative Example 4 lacks a light aroma, and the essential oil of Comparative Example 4 has a somewhat oxidized odor, compared to Examples 1 and 2.
All agreed that the essential oil had an excellent aroma.

Claims (1)

[Scope of Claims] 1. A frozen and pulverized product of citrus peel or citrus juice residue is made water-poorly miscible or water-immiscible under a temperature condition of 10°C or lower and the frozen state of the pulverized product is not substantially lost. 1. A method for extracting citrus essential oil, the method comprising: extracting with an organic solvent, and distilling off the solvent from the extract at a temperature of 50°C or lower. 2. The method according to claim 1, wherein the low temperature extraction is performed under stirring conditions.