JPH0280495A - Dry fractionation of nonlauric fat or oil - Google Patents

Abstract

PURPOSE:To obtain nonflowing lumps of crystals having a high crystallinity by disintegrating lumps of crystals obtained by cooling molten nonlauric fat or oil and fractionating the product into a crystalline part and a liquid part by pressing. CONSTITUTION:Molten (>=50 deg.C) nonlauric fat or oil (e.g., palm oil) is fed to a heat-conductive container of a relatively small depth of liquid, allowed to settle and cooled to 35-20 deg.C at a cooling rate of 0.1-2.0 deg.C/min with chilled air or chilled water of 10-15 deg.C and crystallized to a desired degree of crystallinity to obtain lumps of crystals. These lumps are fed to a mixer or a kneader, disintegrated by a shearing force and frictional heat and compressed to fractionate them into a crystalline part of the higher melting side and a liquid part of the lower melting side.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for economically separating non-lauric fats and oils based on the difference in melting temperature of constituent fats and oils. [Prior Art] (Background) As a method for separating an oily container consisting of a mixture of multiple types of similar components, such as liquid oils and fats, liquid lines, etc., based on the difference in melting temperature of each component, ■Use of a solvent such as acetone or hexane is used. (1) emulsion fractionation method using surfactants, and (2) winkling method using cooling. However, while method ■ above allows for precise separation,
It is dangerous because it uses a flammable solvent, and
The disadvantage is that it is expensive. Method (2) is not only inferior to method (2) in terms of separation accuracy and product quality, but also requires troublesome separation of fats and oils from surfactant solution and wastewater treatment. ■
The second method requires expensive cooling tank equipment, and is much inferior in productivity, separation efficiency, and product quality compared to the first two methods. (Left below) Problems with CtM technology) Therefore, in recent years, a method has been developed in which seed crystals are added to heated and melted fats and oils to promote crystallization (Japanese Patent Publication No. 56-1575).
No. 9 and JP-A-60-101197, etc.) have been proposed. However, in these methods, when the crystallization rate after ripening becomes as high as 40 to 60%, depending on the oil type, the oil loses fluidity completely, making it difficult to discharge it from the crystallizer or handle it afterwards. It has the disadvantage of becoming (Problem to be Solved by the Invention) Therefore, the problem to be solved by the present invention is to dramatically improve the filtration characteristics during compression to eliminate oil species (crystalline lumps) with high crystallinity and no fluidity themselves. The aim is to give industrial possibilities to dry sorting.

[Means to solve the problem]

(Concept) Therefore, the present inventors conducted various studies on means for imparting fluidity to the above-mentioned oil types. As a result, in non-lauric oils and fats such as palm oil, they were gradually crystallized by air-cooling or water-cooling. As a result, the microcrystals in the high melting point part grow in a dendritic shape, and a macroscopic spherical crystal mass is formed in which the amorphous low melting point part is included between the dendritic molds. By simply applying shearing force to the mass, it is possible to not only easily separate it into a crystalline part rich in high melting points and an oily part rich in low melting points, but also to turn the whole into a slurry with a low viscosity that can be transported by pump. The dry fractionation method for oily substances according to the present invention is based on these findings. (Summary) Based on the above findings, the dry fractionation method for non-lauric fats and oils according to the present invention is based on a method for dry fractionation of non-lauric fats and oils according to the present invention. It is characterized by crystallizing to a crystallization rate, crushing the resulting crystal mass, and then squeezing it to separate it into a crystal part and a liquid part. Below, the main matters related to the invention will be described in sections. (Hereinafter in the margin) (Non-lauric fats and oils) The non-lauric fats and oils that are the subject of the present invention include fats and oils that do not substantially contain CI2 saturated fatty acid residues, specifically,
Examples include animal fats and fats such as beef tallow, lard and milk fat, vegetable fats such as palm oil, soybean oil, rapeseed oil, shea butter and monkey fat, transesterified oils, and their hydrogenated or fractionated hydrogenated oils. However, it is of course not limited to the exemplified fats and oils. (Cooling) In the present invention, an air cooling method or a water cooling method is employed as a cooling means. The wind cooling method uses cold gas, especially cold air, as a refrigerant, and since the heat transfer coefficient of air is small, it is suitable for precipitating large oil crystals over a long period of time, and as described below. This is advantageous in stabilizing the cooling rate in the straight part of the cooling curve, which is a preferred embodiment of the invention. However, even with liquid cooling methods that use water or other liquids with large heat transfer coefficients, it is possible to maintain a constant cooling rate in the straight part of the cooling curve by delicately adjusting the refrigerant temperature and flow rate as the product temperature decreases. can. To carry out the method of the present invention industrially, the target non-lauric fat or oil is placed in a vat, tray, or other relatively shallow container and slowly cooled using cold air or temperature-controlled water or a refrigerant. For example, when mixing palm fractionated oil, the target oil is placed in a shallow stainless steel tray at an initial temperature of 50.
'C or higher, cold air temperature 10~15℃, liquid depth 10 ttrm or higher, and cooling rate from 35℃ to 20℃ with a cooling rate of about 0.1~2.0C/min per minute. is preferable. However, the cooling rate here is based on the attached No. 2.
As shown in the figure, it refers to the average cooling rate between A and 8 in the cooling curve of the target oil and fat to be treated, and if this rate is constant, the curve will be a straight line or a flat line. This section is a region where microcrystals of the high melting point fraction in the target oil and fat form primary crystal nuclei. When the temperature drops below this range and reaches the lowest point C of the curve, the product temperature temporarily rises to point D due to the crystal heat generated, and then gradually decreases again until it reaches a temperature approximately equal to the cold air temperature. Point E is reached, after which the force becomes parallel to the time axis. The crystal is
It grows gradually even after passing the D point, and during this period (during the ripening period)
The separation of the crystalline high melting point portion and the amorphous low melting point portion described above becomes more complete (35° C. corresponds to point A and 20° C. corresponds to point B in balm oil, respectively). The above cooling conditions are common not only to palm fractionated oil but also to other non-lauric oils and fats, but the specific implementation conditions are as follows:
This varies considerably depending on factors such as the type of target non-lauric oil, the material and thickness of the vat or tray, the initial temperature, and the desired properties of the fractionated oil. The optimum value should be set experimentally. However, an important point that must be mentioned here is that it is necessary to heat the fats and oils to be treated in advance to a sufficient liquefaction temperature to homogenize them. That is, if microcrystals of high melting point fats and oils are present in the processed fats and oils, these microcrystals become crystal nuclei and induce early crystallization, resulting in a situation similar to that described in relation to the prior art. This makes it impossible to properly sort and dispose of waste. In the above example of fractionated palm oil, 30℃
Although the appearance is clear at a certain temperature, it is in a non-uniform state with high melting point molecular species such as 1,3-dipalmito-2-olein and tribalmitin dispersed as microscopic crystals, so at least the whole It needs to be heated until it becomes uniform. However, the amount of tripalmitin in the single-wort person is very small, and it is presumed that it is in a mixed crystal or eutectic state, so it actually exceeds 65.5°C, which is the melting point of β-type crystals.
There is no need to raise the temperature above 50°.
Heating at about C is sufficient. As mentioned above, the crystalline mass produced in the above cooling process is a macroscopic spherical crystalline mass in which amorphous low-melting point fats and oils are included between the fine structure of high-melting point fats and oils that have grown in a dendritic shape. Yes (see Figure 1). (Crushing) Crushing can be carried out using a mixer on a small scale, but on a large scale, it can be carried out using a kneading machine. During the process of passing through the inside of the machine, the oil is divided by the action of shearing force and frictional heat, and consists of small oil types mainly consisting of high melting point fats and oils and partially melted liquid low melting point fats and oils. Since it becomes a slurry, it can be pumped as is. Note that if this step is omitted and the cake is directly subjected to the next compression step, the liquid portion will not be sufficiently removed from the cake, so the iodine value of the solid portion (crystalline portion) will be lower than the iodine value of the liquid portion, which is lower than the iodine value of the liquid portion. Value (1v
) increases. (Expression) The above non-lauric fat slurry is then pressed and separated into solid fat on the high melting point side and liquid oil on the low melting point side. A four-compartment filter is suitable for this separation, and for large-scale processing, a press-type filter with many greenhouses arranged in parallel is suitable, especially a pressure-resistant rubber diaphragm called a volumetric type or membrane type. 1- so that the greenhouse is compressed statically by
A suitable format is appropriate. In this type of filtration machine, the thickness of the unit greenhouse is as thin as several tens of eleven thousandths of an inch, and the heat transfer efficiency is good, making it easy to control the temperature inside the greenhouse. In addition, even if the volume per group is small, by arranging a large number of them in parallel, a large amount of non-lauric fats and oils, from several tons to several tens of tons, can be processed at a time, which is suitable for carrying out the invention. However, other types of filter presses can be used as well, such as X-press filters, automat presses, tubeless filters or piston presses. [Function] With reference to the attached FIG. 1 which schematically explains the principle of the present invention, the high melting point portion (portion rich in high melting point molecular species) H in fats and oils is as follows:
As it cools, it gradually grows into a dendritic shape to form a small lump P that includes a low melting point part (a part rich in low melting point molecular species) L, and a large number of such Koura lumps P are further joined by the low melting point part L. A large oil seed is formed (A in the same figure). When shearing force is applied in this state, the large oil species will be separated into small unit lumps P, and the low melting point portion that was involved in the bonding will first be liberated. As a result, the small oil type P appears to have lost its bonding cement and gains fluidity (FIG. 8). Next, when this is squeezed, the low melting point part in each small oil type P is pushed out of the oil type by pressure, so it is separated into a crystalline high melting point part and a liquid low melting point part, and the latter is separated from the filter cloth. (2IC).According to the inventor's knowledge, the separation phenomenon of the high melting point portion and the low melting point portion due to the above-mentioned crushing is unique to non-lauric fats and oils. Even if lauric oil such as palm kernel oil is slowly cooled and then crushed, it will never become a slurry.It is unclear what the reason is for this, but in any case, the findings of the inventor are as follows. This can be said to be the discovery of an important characteristic for successful dry fractionation of fats and oils.In addition, in this squeezing process, in order to reduce the residual rate of filtrate on the cake side as much as possible, we tried to form crystal particles as large as possible. The size of the crystal grains mainly depends on the number concentration of crystal nuclei and the crystal ratio, but the former is particularly determined by the straight or painted linear section of the initial cooling curve, and the cooling rate is The larger the number of crystal nuclei, the more rapidly the number of crystal nuclei increases, and as a result, it becomes difficult to grow into large crystal grains.According to the inventor's knowledge, if the cooling rate is approximately 2.0°C/min or less, preferable compressibility is achieved. Crystals can be obtained.However, if this value becomes extremely small, the temperature of the oil and fat will rise significantly due to the crystallization heat accompanying crystal growth.Therefore, cooling becomes difficult and crystallization takes a long time.Therefore, industrially It is difficult to adopt the condition of approximately 0.1 "C/min. As a result, it is not necessary to add low-melting point fats and oils in advance for the purpose of imparting fluidity.This not only improves the throughput of crystallization and compression equipment, but also improves compression filtration. A notable advantage is that the efficiency is significantly improved. [Examples] The embodiments of the invention will be explained below with reference to Examples. However, the examples are for mere explanation and do not exceed the technical scope of the invention. This does not directly relate to the interpretation of L1-3 and 1. The liquid part of palm oil (IV VS2.0) was cooled with cold air at 15°C ± 0.5°C (wind speed 1) under various cooling conditions listed in Table 1 below. ~1
．． After cooling under conditions of 5 ta/sec), the mixture was compressed for 1 hour under a pressure of 28 kg/r:rd using a small filter press with a frame thickness of 20 a+m, with or without crushing. It was divided into a solid part and a liquid part. The results are also shown in Table 1 below. Table-1 *Average value from 35°C to 25°C (see explanation above) As can be seen from the above table, the iodine value of Example 2 that underwent crushing and kneading was the same as that of Comparative Example 1 that did not undergo this process. In comparison, although the liquid part is equivalent, the solid part has a lower value of 4.4. Furthermore, as shown in the results of Examples M1 and 3, even if the iodine value of the liquid part is higher, that is, even if the crystallization rate is more advanced, the iodine value of the solid part can be lowered by going through the above steps. In other words, this shows that the compressibility is significantly impaired. The filtration rates in Comparative Example 1 and Implementation rIA2 were tracked over time, and the results are shown in the attached FIG. 3. As is clear from the figure, the filtration rate when subjected to crushing treatment is approximately twice as high as that when untreated. 11/22 [The same palm oil liquid part as in the previous example was placed in a tray at various liquid depths, and the initial cooling rate was varied between 0.5 and 2.5°C/min to solidify it. After crushing the oil liquid, it was squeezed and filtered in the same manner as in the previous example, and the iodine values of the solid and liquid parts obtained were examined. The results are shown in Table 2 below. As is clear from the table, the quality (iodine value) of the solid portion is greatly influenced by the cooling rate. A preferred cooling rate is approximately 01-2.0'C/min. (Margins below) Parameters and other explanations in each figure outside the table are written in each figure respectively: P: small oil type, H: high melting point part, L: low melting point part.

【Effect of the invention】

As explained above, the present invention provides a dry fractionation method for oily substances with excellent workability and separation efficiency, and thus can contribute to improving oil and fat fractionation technology and reducing fractionation costs.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically explaining the principle of the present invention, and FIG. 2 is a graph schematically showing the form of the cooling curve of the present invention.
FIG. 3 is a graph showing changes in filtration rate depending on the presence or absence of crushing and crosstalk. Figure 1 to Figure 1 Time Procedure Amendment (P-649) September 21, 1985 Pressure Hours/Minutes 2゜3゜4゜Name of the patented invention filed on September 16, 1988 Relationship with the case of a person amending the dry separation method for non-lauric oils and fats Patent applicant address 6-1 Hehata-cho, Minami-ku, Osaka Name Fuji Oil Co., Ltd. Representative Hiroshi Hisamoto

Claims (1)

[Scope of Claims] 1. A homogeneous molten non-lauric oil and fat placed in a heat conductive container is crystallized to a desired crystallization rate by cooling with air or water, and after crushing the obtained crystal mass, A dry fractionation method for non-lauric fats and oils, which is characterized by squeezing and separating into a crystalline part and a liquid part. 2 The cooling rate of the straight line part in the cooling curve of the target oil is 0.
．． The separation method according to claim 1, wherein the air temperature, air speed, water temperature, and/or liquid depth in the container are adjusted so that the rate is 1 to 2.0°C/min. 3. The fractionation method according to claim 1, wherein the crushed fats and oils are compressed at a temperature approximately around the crystallization temperature.