JPH0160199B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for advantageously removing caritenes contained in shea butter. Shea butter is a fat extracted from the fruit of a natural tree called Bassia Parkii, which grows on the west coast of Africa and the Niger area, and is usually fractionated and purified and used as a cocoa fat substitute. The quality of this crude shea butter has deteriorated considerably when it is obtained domestically, with some having an acid value of up to 30. It also contains a large amount of a polyisoprene compound called caritene, which is not found in other fats and oils. If it remains in the fat fraction, when this fraction is used as a cocoa fat substitute, it will cause inhibition of the tempering process during the tyokolate production process. Therefore, when using shea butter as a cocoa substitute fat, it is necessary to remove such caritene, but conventionally, before fractionating the hard butter fraction from shea butter using hexane, a low polar solvent. , the caritene is a polar solvent such as acetone (dielectric constant (ε.20℃) 21.4), methyl ethyl ketone (dielectric constant (ε.17℃) 17.8) or ethyl alcohol (dielectric constant (ε.20℃) 27.0). Taking advantage of its property of being poorly soluble in solvents, shea butter is fractionated using a polar solvent, and a hard butter fraction is collected from which the caritene has been removed to an amount that does not interfere with tempering processing. There is. However, since such conventional methods use two types of solvents, the equipment is expanded and two solvent distillation steps are required, which is not only inefficient, but also requires complicated water management in polar solvents, and solvent purification is difficult. It has various drawbacks such as the need to install a retention column. On the other hand, recently, various methods have been proposed for refining various oils and fats using membranes. For example, JP-A-58-93798 specifically compares rapeseed oil, soybean oil, safflower oil, sunflower oil, cottonseed oil, etc. A simple method has been proposed to remove gum from vegetable oils and fats that have a high gum content. However, since the gummy substances contained in these vegetable oils and fats aggregate with each other and their molecules become gigantic, it is possible to use a membrane with a relatively large average molecular weight cutoff (coarse membrane). While the gum content can be easily removed, the caritene contained in shea butter exists in a monomolecular state with almost no aggregation in non- to low polar solvents, and each has a different molecular weight. Since the membrane has a considerable width, a large amount of caritene passes through the membrane, and it is extremely difficult to remove the caritene to an extent that does not interfere with the tempering process. That is, if the molecular weight cutoff of the membrane is set according to the minimum molecular weight in caritene, the permeation rate of the solution through the membrane is extremely slow, which is completely impractical. Therefore, it is possible to consider a method of performing multiple membrane treatments in several stages, starting with a membrane with a high molecular weight cut-off and successively decreasing the molecular weight cut-off, but even with such a method, the final membrane will still have a small molecular weight cut-off (the membrane will have a small molecular weight cut-off). The processing speed is slow due to the fineness of the membranes (fine), and the work process is complicated as the membrane may be damaged if the pressure is increased.Also, even if it were possible to do so, not only would the equipment be expanded, but many different types of membranes would be required, resulting in economical problems. It also has the disadvantage of being expensive. As a result of repeated research in order to solve the above-mentioned drawbacks, the present inventor obtained the knowledge that caritenes can be easily removed without any problems by using a semipermeable membrane that has been subjected to a specific treatment, and has developed the present invention. It was completed. That is, in the present invention, when removing caritenes contained in shea butter, a shea butter production solution diluted with a non- to low polar solvent is brought into contact with the solution under pressure in advance, so that almost no caritene permeates. The main idea is to bring the membrane into contact with a semipermeable membrane that has been clogged to the point where it separates into a membrane-permeable fraction and a non-permeable fraction, and to recover the purified product by removing the solvent from the membrane-permeable fraction. . As described above, the present invention uses a non- to low polarity solvent without using a polar solvent, and simply uses a semipermeable membrane subjected to a specific treatment to easily and advantageously fractionate caritenes from shea butter. The present invention provides a method. In the present invention, as the raw material shea butter, crude crude oil as-extracted or deacidified oil refined with an alkali can be used. As non- to low polarity solvents, those with a dielectric constant (ε.20℃) of 2.5 or less can be used.
For example, hexane (dielectric constant (ε.20°C) 1.85) is a typical example. On the other hand, polar solvents such as acetone have low solubility in fats and oils, making it impossible to obtain highly concentrated diluted solutions and resulting in inefficient work. In addition, as semipermeable membranes, commercially available solvent-resistant semipermeable membranes,
For example, DUS-40 (trade name, average molecular weight cut off 40000, polyether sulfone type) manufactured by Daicel Corporation, or NTU-4208 (trade name, average molecular weight cutoff 8000, polyimide polymer) manufactured by Nitto Denko Corporation. ) or NTU−
4220 (the same, average molecular weight cut off 20000) is an example, and the cutoff molecular weight is 5000-50000, preferably 30000-
50000 can be applied. If the molecular weight cut-off is less than 5000, the permeation flow rate is extremely slow and impractical. Furthermore, if the molecular weight cutoff exceeds 50,000, it is difficult to cause the membrane to become clogged, and most of the carithenes permeate, making it difficult to achieve the objective. In order to carry out the present invention, it is preferable to dilute raw material shea butter in a non- to low polar solvent so that the fat content becomes 5 to 50% (by weight, the same applies hereinafter). If the oil content is less than 5%, the amount of processing is too small and it is not efficient;
%, the viscosity of the miscella is high and an economical permeation flow rate cannot be obtained, and it is also not efficient. Such a diluted solution is heated to 20 to 70°C, preferably 30 to 60°C, and heated to 12 to 120 kg/ ^cm2 under a pressure of 1 to 10 kg/cm2.
Contact is made with the membrane at a flow rate of m ² /h. Here, it is necessary to cut off a certain amount of the initially permeated fraction.
Although this amount cannot be determined unconditionally depending on the membrane treatment conditions, it is possible to
It can be easily determined by measuring the iodine value of the oil or fat in the membrane-permeable fraction and comparing it with the iodine value of a control oil (for example, oil or fat treated with acetone). According to the inventor's experiments, it appears that it is sufficient to cut off the amount that passes through for about 5 to 10 minutes under the above processing conditions. If this operation is not carried out, caritenes remain mixed in the membrane-permeable fraction, making it impossible to obtain a satisfactory quality. That is, the present invention uses a semipermeable membrane that allows relatively low-molecular-weight caritenes to permeate in the initial stage of membrane permeation, and causes the membrane to become clogged by allowing a certain amount of a diluted solvent solution to pass through it in advance. After that, the desired membrane permeation treatment is carried out. Note that it is advantageous to return the membrane permeation solution cut at the initial stage to the original diluted solution. When carrying out the present invention, a flat membrane may be used when a small amount is to be treated, but a modular membrane may be used when a large amount is to be continuously treated.
In this case, if the concentration of the diluted solution becomes too high to be processed, a new solvent is added to adjust the concentration. According to the present invention, whereas conventionally, the caritenes contained in shea butter were removed by fractionation treatment with a polar solvent, and then the hard butter fraction was fractionated with a non- to low polar solvent, all Since it is possible to use only a non- to low polarity solvent from the beginning and the purpose can be achieved only by using a specific treatment membrane alone, it has the effect that workability is significantly improved. Examples are illustrated below, but the spirit of the invention is not limited thereto. Example 1 Shea fat deoxidized oil having an iodine value of 62.7, a saponification value of 176.7, and an acid value of 1.84 was mixed with N-hexane to obtain a diluted solution having an oil content of 20%. This solution was heated to 40℃ and a membrane with a molecular weight cutoff of 40,000 (DUS-40 manufactured by Daicel Corporation) was used.
The membrane treatment was continued after the ^initial membrane permeation fraction for ¹⁰ minutes was returned to the original diluted solution. The permeable fraction and non-permeable fraction were desolvented to obtain a fraction having the following properties.

[Table] As a control, an acetone solution of 10% shea butter, the same raw material, was heated to 45℃, insoluble matter was filtered out, and the solvent was removed.
A fraction with the following properties was obtained.

[Table] From the above results, it can be seen that caritene is removed to the same extent as in the conventional method in the membrane-permeable fraction of shea butter obtained by the method of the present invention. Example 2 Shea fat deoxidized oil having an iodine value of 61.6, a saponification value of 177.4, and an acid value of 1.69 was mixed with N-hexane to prepare a diluted solution having an oil content of 10%. This solution was heated to 40℃, and a membrane with a molecular weight cutoff of 8000 (NTU manufactured by Nitto Denko Corporation) was
-4208) under a pressure of 5Kg/ ^cm2 .
After contacting at a flow rate of ^m2 /hour and cutting off the initial membrane permeation fraction for 10 minutes, membrane treatment is continued to obtain a permeation fraction and a non-permeation fraction, which are desolvated and have the following properties. A fraction was obtained.

[Table] For comparison, the following experiments were conducted without cutting the initial membrane permeation fraction.

[Table] As a control, the same raw material shea butter was used in the same manner as in Example 1.
% acetone solution, heated to 45°C, undissolved matter was filtered off, and the solvent was removed to obtain a fraction with the following properties.

[Table] From the above results, it is clear that caritenes are removed from the membrane permeable fraction of shea butter obtained by the method of the present invention to the same extent as in the conventional method.

Claims (1)

[Scope of Claims] 1. When removing caritenes contained in shea butter, a shea butter production solution diluted with a non- to low polarity solvent is brought into contact with the solution under pressure in advance so that most of the caritenes permeate. The membrane is brought into contact with a semipermeable membrane that has been made to become clogged until it no longer clogs, is separated into a membrane-permeable fraction and a non-permeable fraction, and the membrane-permeable fraction is desolvated to recover a purified product. Method for removing caritenes from fat. 2. The method according to claim 1, wherein the non- to low polarity solvent is hexane. 3 The oil concentration of the diluted shea butter production solution is 5~
50% (by weight). 4. The method according to any one of claims 1 to 3, wherein the semipermeable membrane has a molecular weight cutoff of 5,000 to 50,000, preferably 30,000 to 50,000. 5. The method according to any one of claims 1 to 4, wherein the initial membrane-permeable fraction, which has been brought into contact with the membrane until clogging occurs, is returned to the original diluted solution.