JPH04252298A - Manufacture of intermediate fraction by fractional crystallization involving recirculation of stearin and olein fractions through transesterification process - Google Patents

Abstract

PURPOSE: To avoid formation of by-products and to improve economy by a method wherein a fatty substances-contg. feedstock is treated by upper part fractionation crystallization and an oleic upper part fraction is treated by lower part fractionation crystallization and an ester exchange mixture is recirculated.

CONSTITUTION: A fatty substances-contg. feedstock is treated by upper part fractionation crystallization to obtain a stearic acid upper part fraction and an oleic acid upper part fraction. Then, the oleic acid upper part fraction is treated by lower part fractionation crystallization to obtain an intermediate fraction and an oleic acid lower part fraction. Thereafter, the above described stearic acid upper part fraction and oleic acid lower part fraction are mixed together to perform ester exchange reaction and the obtd. ester exchange mixture is recirculated to the upper part fractionation crystallization treatment.

COPYRIGHT: (C)1992,JPO

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION The present invention relates to a process for producing mid-fractions of fatty substances (including fats and glyceride oils) by fractional crystallization. The present invention particularly relates to upper separate crystallization (topping).
fractional crystalliza
crystallization) and bottoming
fractional crystallizat
ion), in the method for producing an intermediate fraction,
The stearin upper fraction (st) produced as a by-product
ear topping fraction)
and olein bottom fraction (olein bot
The present invention relates to a method of mixing and interesterifying a toming fraction and recycling the transesterification mixture as additional feedstock.

0002

BACKGROUND OF THE INVENTION Natural glyceride fats and oils contain a large number of different triglycerides, the physical properties of which are largely determined by the chain length and degree of unsaturation of the fatty acid moieties. In order to better adapt natural glyceride fats and oils to specific applications, it is often necessary to separate them into fractions characterized by a homogeneous fatty acid distribution with melting behavior.

[0003] Fractional crystallization can be performed on fats and oils as they are (dry fractionation), or after mixing them with a solvent (solvent fractionation). In the fractional crystallization process, fats and oils are cooled to a temperature such that only the high-melting point triglyceride fraction crystallizes, and then the crystallized solid (stearin fraction) is extracted from the liquid fraction (olein fraction) by, for example, filtration or centrifugation. To separate.

[0004] In the production of intermediate fractions, a stearin topping fraction and an olein topping fraction are used.
) is subjected to a separate crystallization treatment for the upper part. The upper oleic fraction is subjected to a lower-separate crystallization treatment at a lower temperature to obtain a lower oleic fraction and a desired intermediate fraction.

[0005] It is understood that the upper portion separate crystallization treatment and the lower portion separate crystallization treatment may include two or more consecutive fractional crystallizations, in which case the olein fraction and/or the stearin fraction are in the next or previous stage. subjected to fractional crystallization.

[0006]

The intermediate fraction is desirable as a raw fat blend for margarine production. The intermediate fraction has good consistency and good melting behavior, giving the resulting margarine good organoleptic properties as well as reasonable consistency at temperatures in the range 15-25°C. However, the production of intermediate fractions necessarily produces two types of by-products (
that is, an upper stearin fraction and a lower olein fraction). These fractions are generally not very valuable and the process for producing the intermediate fractions is not optimal from an economic point of view.

[0007]

SUMMARY OF THE INVENTION The present invention provides for mixing an upper stearin fraction and a lower oleic fraction when the fatty material feedstock used to produce the intermediate fraction has a triglyceride fatty acid composition similar to that of the intermediate fraction produced. and random transesterification of this mixture, the transesterification mixture has a fatty acid composition similar to that of the feedstock and can be recycled, thus substantially avoiding the formation of by-products. This is based on the discovery that

[0008] The invention therefore provides a method for the production of intermediate fractions by fractional crystallization of fatty substances, comprising: i) subjecting a feedstock containing fatty substances to upper fractional crystallization to give a stearin upper fraction and an oleic upper fraction; ii) subjecting the upper oleic fraction to a lower fraction crystallization treatment to give an intermediate fraction and a lower oleic fraction, and iii) transesterifying the stearic upper fraction and the lower oleic fraction by mixing them. attached to,
and recycling the transesterification mixture of fatty substances to the upper separate crystallization process.

A requirement in the process of the invention is that the stearin upper fraction and the oleic lower fraction are subjected to random transesterification. The process of the invention is therefore not suitable for producing intermediate fractions containing special symmetrical or asymmetrical triglycerides.

Any fatty substance may be used as feedstock, including fully or substantially hydrogenated palm oil, palm kernel oil, tallow, butterfat, fish oil, sunflower oil, as well as their solvents or dry fractionated stearin or Semi-solid glyceride fats and oils of plant, animal or marine origin, such as olein fractions, may be mentioned. Preferred feedstock components include hydrogenated palm oil, hydrogenated palm kernel oil, fractionated palm oil stearin, sunflower oil, such as palm oil hardened to a melting point of 58° C. (C1640-50%;
C1860-50%), hydrogenated palm oil stearin (C1
650-85%; C1850-15%), hydrogenated palm kernel oil hardened to a melting point of 39°C (C1245-55%;
C1412~18%; C165~10%; C1812~
25%), hydrogenated palm kernel oil stearin hardened to a melting point of 41°C (C1250-60%; C1415-25%)
; C165-10%; C185-12%), as well as sunflower oil hardened to a melting point of 69°C (C165-10%; C
1895-90%). Using these feedstock components, intermediate fractions with virtually any triglyceride fatty acid distribution can be formulated.

[0011] When using these hardening feedstock components to obtain an intermediate fraction by solvent fractionation, preferably the intermediate fraction obtained is less than 13, preferably less than 11.
less than

[Formula 1] value (≧C50), as large as possible, usually greater than 60, preferably greater than 64

[C44, C46, C48] and as large as possible, usually greater than 70 (

[Chemical formula 3] ) has a value.

[0012] When obtaining an intermediate fraction by dry fractionation,

[C4] The value is usually less than 16, preferably less than 15,

[C5
] The value is usually greater than 45, preferably greater than 50;
(

[C6] ) value is typically greater than 65.

[0013] For the transesterification in the method of the present invention, any suitable method may be used as long as the fatty acids of the triglyceride are randomly exchanged. Prior art transesterification methods, such as those disclosed in European Patent Publication No. 76,682, may also be used. Preferred catalysts are those containing alkali metals or hydroxides. Preferably, the catalyst system comprises sodium or sodium hydroxide, glyceride, and water in a weight ratio of 1/2/3 to 1/2/7. The catalyst is usually added at a concentration of 0.03% by weight or more of sodium hydroxide based on the weight of the oil. Details thereof are disclosed in European Patent Publication No. 76,682.

In order to optimize the fatty acid distribution of the triglycerides used in the feedstock, it is preferred to subject not only the feedstock, but also the stearin top fraction and the olein top fraction, to transesterification.

Depending on the separation efficiency, solid particle content, crystallization temperature and cooling rate in the fractional crystallization of the upper and lower fractional crystallization treatments, these treatments can be divided into two successive fractional crystallizations, etc. There may be two or more stages.

[0016] When the upper fractional crystallization process includes two or more successive fractional crystallization stages, as in a preferred embodiment of the invention, the stearin upper fraction is obtained from the second stage of upper fractional crystallization. If the upper olein fraction is obtained from the first-stage upper-separation crystallization, the yield of the intermediate fraction can be increased.

When the lower fractional crystallization process includes two or more consecutive stages of fractional crystallization, the olein lower fraction is obtained from the first stage of lower fractional crystallization, and the intermediate fraction is obtained from the second stage of fractional crystallization.
Separate crystallization at the bottom of the stage is preferred in order to obtain intermediate fractions of better quality.

If the oleic upper or lower fraction has a relatively high solids content, it is preferred to dilute the fraction by recycling a portion of it to the upper or lower separate crystallization process. Preferably, the percentage of olein recycled is about 10 to 60%, more preferably 25 to 50%.

[0019] The continuous upper or lower fractional crystallization may be carried out in a countercurrent fractional crystallization as disclosed in the above-mentioned European Patent Publication.

Impurities present in the feedstock or during the production of the intermediate fraction, such as partially saturated triglycerides or diglycerides, can accumulate in the recycled upper stearin or lower oleic fraction. Therefore, it is preferred that small amounts of the upper stearin fraction and/or the lower oleic fraction be disposed of intermittently or continuously without being recycled. The fraction to be discarded constitutes no more than about 5% by weight of the recycled top stearin or bottom olein fraction. Alternatively, such impurities may be removed from the recycled fraction intermittently or continuously, for example by adsorption.

The method for producing the intermediate fraction of the present invention will be explained by the following examples, but the present invention is not limited thereto. The two methods used are shown in Figure 1. In this figure, the boxed area represents the individual fractional crystallizations and subsequent separation of stearin from the olein fraction.

In the batch method, only one crystallizer and
It is possible to use various storage tanks for temporarily storing the olein fraction and stearin fraction obtained in the upper and lower separate crystallization treatments.

[0023]

EXAMPLES Example 1 An intermediate fraction was prepared according to method A. Feedstock (F) containing 47% fully hydrogenated palm oil and 53% fully hydrogenated palm kernel oil was subjected to transesterification (I) with 0.02% by weight of metallic sodium.

[0024] Two-stage continuous countercurrent fractional crystallization (1) and (2) of upper part separate crystallization treatment (crystallization temperature is 44°C, respectively)
The solid particle content (SPC) at 40° C. and 40° C. was 11%. Two-stage continuous countercurrent fractional crystallization (3) and (4) of the lower part separate crystallization treatment (crystallization temperature is 35 °C and 3
SPC at 1° C.) was 17%. The stearin top fraction and olein bottom fraction were recycled to the transesterification step and mixed with the feedstock in a 60/40 ratio. The middle fraction is initially 12/55

[C7
], but the value after steady state was 12/54. For comparison, the separation efficiency in each crystallization was kept at 0.5.

Table 1 shows the fatty acid composition (%) of the intermediate fraction as well as the feedstock.

[0026]

Example 2 A feedstock containing 7% fully hydrogenated and dry-fractionated palm oil stearin, 33% fully hydrogenated palm oil and 60% fully hydrogenated palm kernel oil was prepared using method B. used in the preparation of fractions.

The SPC in the fractional crystallization in the upper portion separate crystallization treatment was 8%, and the SPC in the fractional crystallization in the lower portion separate crystallization treatment was 18%. The stearin top fraction 1 and the olein bottom fraction 2 were recycled to the transesterification step and mixed with the feedstock in a 71/29 ratio.

At a separation efficiency of 0.5, the middle fraction is 15/45

[Chemical formula 8] It had value.

[0030] The fatty acid composition (%) of the intermediate fraction obtained and the feedstock are shown in Table 2.

[0031]

Example 3 The same procedure as in Example 2 was used except that the olein was recycled at a 50% recycle ratio to the feedstock. The SPC in the upper part separate crystallization treatment is 5.4%,
The SPC in the lower part separate crystallization treatment was 12%. The intermediate fraction obtained was 15/45

[Chemical formula 9] It had value.

Example 4 Containing 1.5% fully hydrogenated sunflower oil, 46.5% fully hydrogenated palm oil, 26% fully hydrogenated palm kernel oil and 26% fully hydrogenated palm kernel stearin. The feedstock was processed according to Method A. In the upper part separate crystallization process, the SPC in crystallizations 1 and 2 was 8%. In the lower part separate crystallization process, the SPC in crystallizations 3 and 4 was 16%. The stearin top fraction and olein bottom fraction were recycled and mixed with the feedstock in a 62/38 ratio. At a separation efficiency of 0.5, the intermediate fraction

[Chemical formula 10] The value was 12/49.

Table 3 shows the fatty acid composition (%) of the intermediate fraction as well as the feedstock.

[0035]

Example 5 A feedstock containing 42% hydrogenated palm kernel stearin, 53% hydrogenated palm oil and 5% hydrogenated sunflower oil was prepared in acetone at a weight/weight ratio of 1/5. It was subjected to solvent fractionation. The SPC in the upper part separate crystallization treatment is 2
9%, and the crystallization temperature was about 30°C. The SPC in the lower section crystallization process was 33% (based on fat present) and the crystallization temperature was approximately 20°C. After recirculating the stearin upper fraction 1 and the olein lower fraction 2 and removing the acetone, the feedstock and 47.5
/52.5 and then transesterified. The fatty acid composition of the intermediate fraction was very similar to that of the feedstock as seen in Table 4.

[0037]

of the intermediate fraction

embedded image The value was 14/59. Sometimes it was necessary to remove diacylglycerol by adsorption on silica. The time interval between these impurity removal operations depended on the feedstock composition.

Example 6 A feedstock containing 85% palm oil and 15% solvent fractionated palm oil stearin was used in Method B. The intermediate fraction obtained was 1.2%

[Chemical formula 12] , 67%

[Chemical formula 13] , 6.3%

[Chemical formula 14] , and others had a constant composition of 25.5%.

Example 7 An intermediate fraction was prepared according to method C. Feedstock containing 43% fully hydrogenated palm kernel oil, 0.02%
The mixture was subjected to transesterification (1) using sodium metal. Two-stage continuous countercurrent fractional crystallization (1
) and (2) (crystallization temperatures are 44°C and 48°C, respectively)
The solid particle content (SPC) was 18.5%. The SPC in the lower portion separate crystallization (3) (crystallization temperature was 38° C.) of the lower portion separate crystallization treatment was 18.5%. The stearin top fraction and the olein bottom fraction are recycled to the transesterification process and are combined 50/5 with the feedstock.
0

They were mixed at the following ratio: steady state

embedded image The ratio was 12/52. For comparison, the separation efficiency was set to 0.
I kept it at 5. Table 5 shows the fatty acid composition (%) of the intermediate fractions as well as the feedstock. Generally, method C can be used for systems where SE is still high at SPC.

[0042]

[Brief explanation of the drawing]

FIG. 1 is a flow diagram illustrating three methods of implementing the present invention. In the figure, the boxed areas represent the individual fractional crystallizations and subsequent separation of stearin from the olein fraction.

Claims (14)

[Claims] 1. A method for producing an intermediate fraction by fractional crystallization of a fatty substance, comprising the steps of: i) subjecting a feedstock containing a fatty substance to an upper fraction crystallization process to give a stearin upper fraction and an oleic upper fraction; ii) subjecting said oleic upper fraction to a lower fraction separate crystallization treatment to give an intermediate fraction and an oleic lower fraction; iii) subjecting said stearic upper fraction and oleic lower fraction to a mixture and transesterification;
and recycling the transesterification mixture of fatty substances to the upper separate crystallization process. 2. Process according to claim 1, characterized in that the mixture of the upper stearin fraction and lower oleic fraction and the feedstock are subjected to transesterification. 3. A method according to claim 1 or claim 2, characterized in that the upper portion separate crystallization treatment includes at least two consecutive upper portion separate crystallizations. 4. The method of claim 3, wherein the stearin top fraction is obtained from a second stage of top separate crystallization, and the olein top fraction is
A method characterized in that the crystal is obtained from separate crystallization of the upper part of the stage. 5. A method according to any one of claims 1 to 4, characterized in that the lower section crystallization treatment comprises at least two consecutive lower section crystallizations. 6. The method according to claim 5, wherein the lower olein fraction is obtained from a first-stage lower-separation crystallization, and the intermediate fraction is obtained from a second-stage lower-separation crystallization. A method characterized by: 7. A method according to any one of claims 1 to 6, characterized in that a part of the oleic upper fraction is recycled to the upper fraction separate crystallization process. 8. The method of claim 7, wherein the rate of recycling of the oleic top fraction is between about 10 and 6.
0%, preferably about 25 to 50%. 9. A method according to any one of claims 1 to 8, characterized in that a portion of the olein lower fraction is recycled to the lower fraction separate crystallization process. 10. Process according to claim 9, characterized in that the proportion of the oleic lower fraction recycled is about 10 to 60%, preferably about 25 to 50%. 11. A method according to any one of claims 3 to 10, characterized in that the successive upper and/or lower fractional crystallization comprises countercurrent fractional crystallization. 12. A method according to any one of claims 1 to 11, characterized in that the fractional crystallization is selected from solvent crystallization and dry crystallization. 13. A method according to claim 1, characterized in that impurities are removed from the stearin upper fraction and/or the olein lower fraction. 14. Process according to any one of claims 1 to 13, characterized in that a small amount, typically less than 5%, of the stearin upper fraction and/or olein lower fraction is discarded. .