JPH0214290A - Method for dry fractionation of fats and oils - Google Patents

Abstract

PURPOSE:To improve treating performance and filtration efficiency of a crystallizer and filter by cooling and crystallizing a nonlaurin fats and oils, disintegrating and fluidizing the fats and oils and fractionating the fats and oils into a crystal and liquid parts by filtrating, etc. CONSTITUTION:Nonlaurin fats and oils consisting of animal fats and oils, such as beef tallow or lard, and vegetable fats and oils, such as palm oil, soybean oil or rapeseed oil, are slowly precooled preferably by air- or water-cooling and crystallized until the crystallization ratio after compression attains 20-70wt.% (preferably 30-60wt.%). The resultant cooled fats and oils are then physically disintegrated, fluidized, then filtered or compressed and fractionated into preferably a needlelike or dendritic crystal part and a liquid part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a technique for separating fats and oils based on the difference in melting temperature of constituent fats and oils.

[Conventional technology]

(Background) Methods for separating oily substances consisting of a mixture of multiple types of similar components, such as liquid oils and fats, liquid wax, etc., based on the difference in melting temperature of each component include: ■ organic solvent fractionation method such as acetone or hexane, and ■ surfactant Known methods include the detergent fractionation method that uses chemicals, ■winkling method, and ■sweating method.

Among these methods, the method (■) allows for precise separation, but it is dangerous and costly because it uses a flammable solvent.The disadvantages of the method (■) are that Not only is the separation accuracy and product quality inferior to method (2), but the separation of fats and oils from surfactant solution and wastewater treatment are troublesome. Also, the separation efficiency and product quality are much inferior to the former two methods.Method (2) is applicable to limited raw material properties, and although it is used for dewaxing, it is not suitable for separating oils and fats.

(Problems with the Prior Art) Conventionally, in the method (1) above, a method has been widely used in which a vertical crystallization tank equipped with a stirrer is used to lower the temperature of the refrigerant in stages to cause gradual crystallization.

In this method, slurry-like crystals are extracted from the bottom of the tank after crystallization is completed, and are separated into a crystal side and a liquid side by compressing and filtering with a heald press, filter press, etc. in a subsequent step. Generally, the crystal side ratio is 10 to 30% by weight.
The above operation is possible under the following conditions where the crystal ratio is relatively low, but when the crystal ratio is 30% by weight or more, especially 40% by weight.
At concentrations of up to 70% by weight, the crystal mass usually loses its fluidity and cannot be discharged from the crystallizer unless it is crystallized with stirring.

Therefore, in order to obtain a high crystallization rate, it is necessary to perform crystallization while continuing to stir gently, but if this is done, the resulting crystals tend to enclose the liquid portion, resulting in a significant drop in crystal quality. Moreover, a powerful stirring device is required for stirring, which increases the equipment cost.

For the above reasons, the existing method uses 10 to 30% by weight.
Currently, it is operated under operating conditions with a relatively low crystal ratio, but because of the low crystal ratio, low melting point components cannot be sufficiently concentrated, resulting in poor product quality. There is.

[Problem to be solved by the invention]

Based on the above circumstances, the problem to be solved by the present invention is to solve the problem of dry fractionation of fats and oils that have a high degree of crystallinity and form a quasi-solid state (a state with no or almost no self-flowing property) at the end of crystallization. The goal is to provide industrial possibilities.

[Means to solve the problem]

(1 already required) Therefore, the present inventors aimed to impart fluidity to the above-mentioned fats and oils.
As a result of various studies on methods, we found that, especially for non-lauric oils such as palm oil, it is possible to crush and knead oils and fats with a high crystal ratio that have been solidified by crystallization by applying appropriate shearing force or physical vibration. It was surprisingly found that the slurry was transformed into a creamy, self-flowing slurry, and that the treated slurry had significantly better filtration properties than the untreated crystalline mass.

The dry fractionation method for fat and oil substances according to the present invention is based on the above knowledge, and is a method for cooling and solidifying non-lauric fats and oils and fractionating them into a solid part and a liquid part. After cooling the oil and fat to crystallize it to a desired crystal ratio, physically crushing it and fluidizing it,
After that, it is characterized by being squeezed and separated into a crystal part and a liquid part.

(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,
For example, animal fats such as beef tallow and pork fat, palm oil, soybean oil,
Vegetable fats such as rapeseed oil, shea butter, monkey fat, etc., transesterified oils, hydrogenated oils or fractionated hydrogenated oils thereof, etc. can be mentioned, but the oils and fats are of course not limited to the exemplified fats and oils.

(Cooling) Although there are no particular restrictions on the cooling means used in the present invention, crystals with better crushing effects and squeezing performance grow densely in a needle or dendritic shape and form small lumps with a size of several tens of microns or more. It is important that it is formed, and it is usually obtained by crystallizing it under fairly gentle cooling conditions and under standing conditions. For example, in the case of palm oil, it is first melted at a temperature of about 50 to 60°C, then slowly cooled and crystallized under air cooling or water cooling at 10 to 20°C. Dendrites precipitate. This crystal mass is easily fluidized by crushing, and the squeezing performance is significantly improved. however,
These conditions can vary considerably depending on the type of target fat, the cooling rate, and the desired properties of the fractionated fat.

In addition, when water is used as a refrigerant, it is necessary to reduce the cooling rate sufficiently before crystal precipitation, and therefore delicate consideration is required in adjusting the water temperature.

The crystal mass obtained as described above is a microscopically non-uniform mass in which amorphous low melting point components are mixed between the high melting point crystals.

(Crushing) Crushing is performed using a low-speed mixer, auger, kneading machine, etc., but it is a process that physically disperses aggregates of crystals that have grown into needles or dendrites, and the crystal structure It must not destroy itself. Oil wash is divided and crushed inside these machines by mechanical effects such as shearing, impact, and tensile force, and small oils and fats, mainly high melting point fats, are partially melted into liquid low melting point fats and oils. It becomes a slurry that is dispersed in the water, so it can be transported as is with a pump.

Note that if this step is omitted, as mentioned above, in a state where the crystal ratio is high (pump transportation is not possible, and even if the cake is directly subjected to the next pressing step, the removal of the liquid part from the cake will be insufficient). Therefore, the iodine value of the solid part increases while the iodine value of the liquid part is low.

(Squeezing) The above non-lauric fat slurry is then filtered or squeezed and separated into solid fat on the high melting point side and liquid fat on the low melting point side. Any method can be used for filtering or squeezing, and an appropriate method is selected depending on the quality of the product to be obtained and the raw material fat.

[Effect]

Referring to the attached Figure 1, which schematically explains the principle of the present invention, the high melting point part (the part rich in high melting point molecular species) H in the oil and fat gradually grows into a dendritic shape as it cools, and the low melting point part (The part that is rich in low melting point molecular species) forms small fats and oils P that envelop L, and a large number of such small fats and oils P form relatively weak bonds with each other to form large fats and oils (Figure A). When a shearing force is applied in this state, the weak bonds between the small fats and oils are broken, and the large fats and oils are decomposed into unit small fats and oils P, and the low melting point parts trapped between the small fats and oils are first released. As a result, the small oil P appears to have lost its bonding cement and gains fluidity (FIG. B).

Next, when this is filtered or squeezed, the low melting point part is pushed out of the fat and oil and is separated into a crystalline high melting point part and a liquid low melting point part, and the latter is discharged through the filter medium to the outside of the filter chamber. (Figure C).

According to the inventor's knowledge, the above-described separation phenomenon of high melting point parts and low melting point parts by crushing is unique to non-lauric fats and oils, and even if lauric fats such as palm kernel oil are crushed, it will never occur. It will not become a slurry state. It is unclear what the reason for this is, but in any case, the knowledge obtained by the inventor is that
This discovery is an important characteristic for successful dry fractionation of this oil-based oil.

In short, according to the present invention, even if the solidified fat has a high crystal ratio, it is possible to obtain a fluid state to the extent that it can be transported by pump by crushing it, so it is necessary to add a low melting point fat in advance for the purpose of imparting fluidity. Nor.

Therefore, not only the throughput of the crystallization and filtration apparatus is improved, but also the filtration efficiency is significantly improved.

[Examples] Hereinafter, embodiments of the invention will be explained using Examples, but the examples are for mere explanation and do not directly relate to the interpretation of the technical scope of the invention.

Example 1 and Comparative Example 1 After cooling the liquid part of palm oil under the cooling conditions listed in Table 1 below,
28kg/ct with or without crushing using a small filter press with a frame thickness of 20 mm? The mixture was pressurized for 1 hour under + conditions and divided into a solid part and a liquid part. The results are also shown in Table 1 below.

Table 1 As can be seen from the table above, those that have undergone crushing and kneading have more advanced crystallization and a higher liquid iodine value than those that have not undergone this process. It is clear that the solid-side yield and iodine value after pressing are both significantly low, indicating that the pressing can be carried out effectively.

Example 2 The same palm oil liquid part as in Example 1 was cooled and solidified at 15°C, and the oil wash was compressed as it was or after crushing, using the same filter press as on the same side, and the filtration rate was measured over time. I tracked it down.

The results were as shown in Figure 2.

As is clear from the figure, the filtration rate when crushed is approximately twice as high as when it is not crushed.

〔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]

Attached Figure-1 is an explanatory diagram schematically explaining the principle of the present invention,
Attached Figure 2 is a graph of the effect on filtration performance. Attachment [1-1 Attachment figure-2 Squeezing time opening/Masu procedure amendment document October 11, 1986

Claims (1)

[Claims] 1. A method for cooling and solidifying non-lauric fats and oils and fractionating them into a solid part and a liquid part, in which the fats and oils are cooled in advance with a device having a cooling function and crystallized to a desired crystal ratio. A method for dry fractionation of fats and oils, which is characterized in that the oil is then physically crushed to be fluidized, and then filtered or compressed to separate it into a crystal part and a liquid part. 2. The fractionation method according to claim 1, wherein the crystal ratio after compression is 20 to 70% by weight, preferably 30 to 60% by weight. 3. The fractionation method according to claim 1, wherein the oil lump solidified by cooling is crushed by a device equipped with a physical kneading or crushing mechanism. 4. The fractionation method according to claim 1, wherein the oil and fat is cooled slowly by air cooling or water cooling to produce needle-like or dendritic crystals.