JPH0456876B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for extracting and separating oil from adlay. More specifically, the present invention relates to a method for extracting and separating a high-grade oil (hereinafter referred to as coix oil) from coix seed, coix sugar, coix germ, etc. (hereinafter referred to as colay raw material) using supercritical carbon dioxide as an extraction agent. Coix is a plant belonging to the Poaceae family, and there are records that it has been used since ancient times not only in China and Southeast Asia, where it is said to have originated, but also in Brazil, Greece, Rome, etc., and its seeds seem to have been prized as a health food and beauty food all over the world. . It seems that it was introduced to Japan about 300 years ago and was cultivated in small quantities for home use and medicinal purposes. Coix barley (hereinafter referred to as Coix seed) is characterized by its extremely high protein and lipid content, and the protein content of white sugar grains is as high as 10%. Its main components are glutamic acid, broline, leucine, etc., and the amino acid composition is the same as that of general vegetable proteins. The lipid content is about 6% in refined grains, and can reach up to 30%, especially in the germ seed coat. Therefore, adlay is also promising as a vegetable oil resource; its lipid properties belong to non-drying oils, and its fatty acid composition is mainly composed of oleic acid, which is not much different from ordinary vegetable oils. However, since ancient times, pearl barley has been known as a herbal medicine called yokuinin and used as a wart remover.
Other services include healing tonic, neuralgia, rheumatoid arthritis, stomach and intestine regulation,
Since it has been used as a medicine for diuresis and diabetes, it is thought to have a different effect from the above-mentioned general vegetable oils. In addition, it is also used as a cosmetic product that is effective against dark skin, age spots, freckles, shark skin, rough skin, pimples, acne, etc. Furthermore, since it can be expected to have various effects, pearl barley is used as it is, such as pearl barley tea, In addition to making pearl barley flakes, they can also be processed to make soy sauce, miso, natto, jelly, etc.
It is made into sweets and commercialized as a health food. In order to extract and separate the oil that is the main component of pearl barley, which has many benefits, it is necessary to
-It is common to extract using an organic solvent such as hexane, but the acid value of the fats and oils in the raw material for adlays tends to increase, similar to rice sugar, and increases by nearly 50 in one or two days. For this reason, when extracting with n-hexane, substances with high acid values are also extracted at the same time, and with ordinary purification methods such as distillation, there is a lot of loss and it is very difficult to separate high-quality substances. Furthermore, since the heating conditions are required for a fairly long period of time to distill off n-hexane, there are also drawbacks such as some oil components undergoing thermal deterioration and changing in quality. Furthermore, the pesticide components contained in adlays tend to be extracted as is and enter the product, which also requires a special removal process. Furthermore, when the residue (lees) of adlay raw material is used as feed for livestock, it is also subject to heat alteration, resulting in a decrease in quality. Furthermore, as it goes through such a complicated process, it is not an economically advantageous method. Also, oil extraction method by mechanical compression (Japanese Patent Application Laid-Open No. 55-35052)
However, this method is also difficult to purify and is not an economical method. Methods such as this external molecular distillation operation, ion exchange resin treatment, and silica gel adsorption have also been proposed, but none of them can be said to be more advantageous for industrial implementation than the solvent extraction method. In view of this situation, the inventors of the present invention have conducted intensive studies on an industrially advantageous method for obtaining high-grade coix oil, and have found that it is possible to extract and separate coix raw material using supercritical carbon dioxide as an extractant. The inventors learned that high-quality adlay oil could be obtained by eliminating the drawbacks of the solvent extraction method, and further studied the extraction process, type of extractant, extraction separation conditions, etc., and completed the present invention. That is, the purpose of the present invention is to provide an industrially advantageous method for extracting and separating high-grade coix oil from coix seed raw materials. This is a method for extracting adlay oil, which is characterized by performing partial extraction over time using carbon dioxide in a supercritical state as an extraction agent, and obtaining adlay oil with a low acid value as a late extraction portion. A method of separating organic compounds from a mixture containing them using a fluid in a supercritical state is known, for example, as described in Japanese Patent Publication No. 10539/1982, but a method for extracting coix oil from coix raw material is not known. It's still completely unknown. A supercritical fluid is a gas that exceeds the critical temperature and pressure, such as ethylene (9.9℃, 50.5atm), ammonia (132.3℃,
111, 3 atm) and carbon dioxide (31.0, 72.9 atm), which are in conditions above the critical state, and are fluids with a density close to that of a liquid and a large diffusion coefficient close to that of a gas. Because of this physical property, various specific compounds can be extracted quickly and efficiently in large quantities, and moreover, it has the characteristic that no extracting agent remains in the product. In general, any of the fluids in the supercritical state can be used in the present invention, but since the subject matter is food, carbon dioxide is harmless and inert, and can be processed at relatively low temperatures. in,
CO ₂ is usually used as the extractant because it enjoys a number of advantages, such as ease of handling and operation and economic advantage. Embodiments of the present invention will be described below based on a flow sheet. In Fig. 1, CO ₂ from cylinder 1 to compressor 2
CO ₂ compressed to a predetermined pressure using a heat exchanger 3 is brought to a predetermined extraction temperature to a supercritical state and introduced into an extraction column 4 . The extraction tower 4 is filled with the raw material Coix barley, and the CO ₂ phase from which the oil has been extracted is reduced in pressure through the pressure reducing valve 5 and guided to the separator 6 to separate the oil from the CO ₂ . The depressurized CO ₂ is cooled and liquefied in condenser 7 and recycled via compressor 2. In the above process, the supercritical state inside the extraction tower
The pressure of CO ₂ is 70-500Kg/cm ² , preferably 70-300
Kg/cm ³ , and the temperature must be kept in the range of 30 to 90°C, preferably 30 to 60°C for extraction. If the pressure and temperature are too lower than the lower limit, a supercritical state will not be achieved, and if the pressure and temperature are too high than the upper limit, not only will the equipment cost increase, but also adverse effects such as thermal deterioration may occur. When the extracting agent is CO ₂ , good results can be obtained especially under conditions of a pressure of around 200 Kg/cm ² and a temperature of around 40°C. In the process shown in FIG. 1, the oil is separated over time by the separator 6, but the components of the oil obtained differ depending on the method of separation.
It is preferable to carry out divided extraction depending on the quality of the desired oil component, and select the initial extracted fraction, middle extracted fraction, and/or late extracted fraction. By the method of the present invention, it is possible to obtain high-quality adlay oil with an extremely lower acid value than that of the late-stage extract, and the following superior effects can be achieved compared to conventional methods. (1) Since a fluid in a supercritical state is used, oil is completely separated from the extraction phase, and there is no possibility of oil remaining as in the case of organic solvent extraction. (2) Oil residue (lees) can be used as feed, etc.
It is economical because it does not require a solvent removal step as in the case of organic solvent extraction. (3) When performing split extraction, free fatty acids are preferentially extracted, so the initial extraction consists of high acid value oils,
Middle and late extracts, especially late extracts, have low acid value oil. (4) The color of the extracted phase is very good, and deacidification and decolorization steps by neutralization are not necessary or their load is small. (5) Less unsaponifiable matter. (6) A highly safe oil with less extractable pesticide components can be obtained. (7) Tocopherols can be recovered with good yield. (8) Since it is operated under mild temperature conditions and in an inert atmosphere, the oil component does not deteriorate. In this way, extraction and division are carried out simultaneously by the method of the present invention, and high-grade pearl barley oil with a lower acid value is immediately obtained, especially from the late-stage extract, which can be used as it is for various uses such as cosmetics, health foods, and medicine. Even if purification is required, it is simple. EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto. Example 1 2.5 kg of adlay raw material having a moisture content of 10.37%, an oil content of 21.48%, and an acid value of 35.21 was packed into an extraction tower with an internal volume of 5, and the extraction temperature was 40°C and the pressure was 100~100°C using the process shown in Figure 1.
Extraction was performed using 250 kg/cm ² of CO ₂ and separation was performed at room temperature and atmospheric pressure to obtain approximately 445 g of oil. 1st extract (A) 14g, 2nd extract (B) 42g divided over time
When we analyzed the composition of the third extract (C) 111g, the fourth extract (D) 139g, the fifth extract (E) 97g, and the sixth extract (F) 42g, the analysis results were as follows: It was as shown in Table 1. For comparison, analytical values for oil extracted using conventional n-hexane are also shown.

【table】

【table】 Table 2 shows the analytical values for the raffinate residue (lees).

【table】 [Brief explanation of the drawing]

FIG. 1 is a flow sheet showing an embodiment of the present invention.

Claims (1)

[Claims] 1. In extracting and separating the oil contained in adlay, adlay sugar, adlay germ, etc., carbon dioxide in a supercritical state is used as an extractant to perform partial extraction over time to reduce the amount of the late extract. A method for extracting adlay oil, which is characterized by obtaining adlay oil having an acid value. 2 Pressure of carbon dioxide in supercritical state 70-300Kg/
^2. The method according to claim 1, wherein the extraction is carried out at a temperature in the range of 30 to 60°C.