HK1069076B - A process for obtaining an oil composition and the oil composition obtained therefrom - Google Patents

Description

Method for obtaining an oil composition and oil composition obtained thereby

Technical Field

The present invention relates to a process for obtaining an oil composition and to the oil composition thus obtained. More particularly, the present invention relates to a process for obtaining oil from palm oil, palm olein or palm stearin mixed with unsaturated soybean oil, corn oil, canola oil, rapeseed oil, sunflower oil and the oils thus obtained.

Background

Fractionation of oils and fats is a well known method for altering the composition of natural oils. Various methods using dry, detergent or solvent processes are patented by companies such as Alfa Laval, Tirtlaux, De Smet, etc. Natural fats consist of triacylglycerols, diacylglycerols, and small amounts of complex mixtures including tocopherol/tocotrienol, sterols, and other unsaponifiable components. The melting and crystallization properties of the oil depend on the fatty acids and triacylglycerols in the oil.

To obtain more liquid fraction of palm oil, the higher melting triacylglycerols may be separated by a cooling process, leaving the unsaturated portion of triacylglycerols-which is filtered through a membrane filter press. Multiple fractionation has been recommended to obtain higher unsaturated olein fractions. The increased use of palm oil in the world market requires products with high fluidity and high definition at low temperatures. A more fluid oil can be obtained by mixing, which is achieved by mixing palm olein with an unsaturated oil.

Most unsaturated oils have a high content of linoleic and linolenic fatty acids. Except that olive oil, which has a high oleic acid content, is promoted as the best oil for human consumption. Furthermore, for more health conscious consumers, this trend is moving towards fats with lower saturations and lower polyunsaturations. New oils of this modified composition have been developed by plant design and production.

As is well known to those skilled in the art, conventional palm olein with an Iodine Value (IV) of 56 has an oleic acid content of 43% to 45% and a linoleic acid content of 11% to 14%, whereas conventional palm olein with an IV of 65 has an oleic acid content of 47% to 49% and a linoleic acid content of 14% to 16%. The content of saturated fatty acid is 29-31%.

Considerable attention has been paid in this field in recent years and some inventions have been patented. US patent No. 4,948,811 relates to triacylglycerol cooking/salad oil compositions having balanced fatty acid ester content for health benefits. The fatty acid esters in the triacylglycerols of the oil comprise from about 60% to about 92% oleic acid, from about 5% to about 25% linoleic acid, from 0% to about 15% alpha-linolenic acid, and less than 3%, preferably less than 1%, saturated fatty acids.

US patent No.5,843,497 and its continuation-in-part and US patent No.5,578,334 both relate to fat blends and to methods of preparation thereof and to the use thereof in food products for stabilizing or lowering low density lipoprotein cholesterol (LDL or LDL-C) and increasing high density lipoprotein cholesterol (HDL or HDL-C) concentrations in the plasma of humans.

US patent No.5,874,117 relates to blending corn oil with palm oil and other palm fractions to obtain a shortening blend with good antioxidant properties. More specifically, the shortening mixture is prepared by simply blending commercially available palm oil, fractionated palm oil components (olein, superolein, stearin and fractionated middle fractions) and/or palm kernel oil with corn oil. This shortening is a cost effective alternative to the following products: products prepared by partial hydrogenation of vegetable oils, transesterification of fats with oils and the addition of oxygen-susceptible fats and oils containing oxidizing agents.

US patent No.6,034,130 provides a synthetic Triacylglycerol (TAG) composition of a composition that is close in composition and structure to human milk, which uses a synthetic approach to the addition of polyunsaturated fatty acids (PUFAs) -which do not cause significant destructive oxidation of the PUFAs.

Furthermore, a research paper written by dr. siewwwai Lin under the name of ° c catalysis Behaviour of Palm oils and Some Blended Products ", by one of the present inventors, was published at the international Palm oil conference (pipac) of the institute for Palm oil in malaysia, held between 1 and 6 months 2 and 1999. In this paper, the relationship of the crystallization properties chemistry of different types of palm olein (based on IV) is discussed. Oleins with excellent cold stability can be obtained by the method discussed in this paper.

Summary of The Invention

Accordingly, the present invention provides a process for obtaining an oil composition, the process comprising the steps of: (a) mixing a vegetable oil with an unsaturated oil in a predetermined ratio to form a mixture, the unsaturated oil having an oleic acid content of greater than 20% and linoleic and linolenic acid contents of greater than 30%; (b) heating the mixture at a temperature of 50 ℃ to 75 ℃ until all crystals are molten; (c) cooling the liquid from step (b) to obtain a mixture of oil and crystals, wherein the crystals are of a suitable size and shape to allow efficient separation of the oil and crystals; and (d) separating the mixture of oil and crystals to obtain an oil composition.

Furthermore, the present invention also provides an oil composition obtained by a process for obtaining an oil composition, comprising the steps of: (a) mixing a vegetable oil with an unsaturated oil in a predetermined ratio to form a mixture, the unsaturated oil having an oleic acid content of greater than 20% and linoleic and linolenic acid contents of greater than 30%; (b) heating the mixture at a temperature of 50 ℃ to 75 ℃ until all crystals are molten; (c) cooling the liquid from step (b) to obtain a mixture of oil and crystals, wherein the crystals are of a suitable size and shape to allow efficient separation of the oil and crystals; and (d) separating the mixture of oil and crystals to obtain an oil composition.

The invention comprises certain novel features and a combination of parts hereinafter fully described and particularly pointed out in the appended claims, although various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

Description of The Preferred Embodiment

The present invention relates to a process for obtaining an oil composition and to the oil composition thus obtained. More particularly, the present invention relates to a process for obtaining oil from palm oil, palm olein or palm stearin mixed with unsaturated soybean oil, corn oil, canola oil, rapeseed oil, sunflower oil and the oils thus obtained. Hereinafter, the present specification will describe the present invention according to a preferred embodiment of the present invention. However, it should be understood that the description is limited to the preferred embodiments of the invention only for the convenience of discussion of the invention, and it is envisioned that those skilled in the art may devise various modifications and alterations without departing from the scope of the appended claims.

Vegetable oils such as palm oil, olein or stearin are mixed with unsaturated oils such as soybean oil, sunflower oil, corn oil, canola oil, rapeseed oil, in proportions which are not too high to avoid defeating the purpose of the fractionation process and to the extent effective the feasibility of the process. The oleic acid content of the unsaturated oil exceeds 20% and the linoleic and linolenic acid contents exceed 30%. The novel liquid oils obtained by this process are transparent and can be used as salad oils, cooking oils and the like. The stearin in such a mixture can be used in margarines and shortenings.

In order to prepare a fraction with very low unsaturation, the inventive step is that a small amount of unsaturated oil will improve the fractionation process in such a way that most of the unsaturated triacylglycerols can be effectively retained in the liquid phase.

According to the method, the oil base is cooled from a temperature above the melting point of the oil to a temperature of 8 ℃ to 20 ℃.

According to the invention, the crystallization time can vary from 4 hours to 24 hours. The use of the method according to the invention has significant advantages in terms of oil compositions whose products contain high nutritional value. Furthermore, the oils obtained by this process have a high IV and remain liquid at 15 ℃.

The advantage according to the invention is that a liquid fraction is obtained which contains saturated fatty acids to monounsaturated fatty acids to polyunsaturated acids in a ratio of 1: 1. The advantages of this oil composition can be seen in the AHA step 1 recipe recommended by the American Heart Association (AHA). According to the invention, such a fraction is also obtained therefrom: if the content of monounsaturated fatty acids is 1, the content of saturated fatty acids may be 1.0 or more, and the content of polyunsaturated fatty acids is very low, as shown in examples 4 and 5. Also, slightly lower saturated and polyunsaturated fatty acids than monounsaturated fatty acids can be achieved by the present invention, as shown in examples 7 and 8. Oils with a near 1.0 ratio of monounsaturated and polyunsaturated fatty acids and slightly lower saturated fatty acids can also be obtained by the present invention, as shown in examples 8 and 9. In order to obtain a composition with a ratio of saturated fatty acids to monounsaturated fatty acids to polyunsaturated fatty acids of 1: 1 using the pure mixture alone, it is necessary to mix palm olein with an IV of 60 and 60% corn oil or 40% soybean oil.

According to the state of the art palm olein with IV 56 requires mixing with unsaturated oils in high proportions to obtain sufficient polyunsaturated degree. However, according to the present invention, both conventional palm oil and palm oil blended with a very low percentage of unsaturated oils may be used.

By the present invention, an oil having a similar composition ratio to olive oil can be obtained, as shown in example 10.

Also, oils with compositions suitable for infant fat formulations can be derived therefrom, so that palmitic, oleic and linoleic acids are within the desired range of infant fat and milk expressed from lactating mothers, as shown in example 11.

In the current palm oil extraction method, after melting at 60 ℃ to 70 ℃, palm oil is crystallized under appropriate cooling conditions. The crystals are filtered through a low-pressure or high-pressure filter press. Under these conditions, the IV of the resulting oil is typically close to 56, further fractionation to lower temperatures will yield oils with IV as high as 60 to 65.

In the fractionation process of the present invention, three successive stages are required. In the present invention, the mixing of the oil mixture must have a suitable melting point and crystallization properties. The most suitable cooling curve is verified by Differential Scanning Calorimetry (DSC) plots of its cooling and melting processes. Pre-analysis of the oil mixture by DSC enables the most suitable cooling process to be used. The ratio of palm oil to unsaturated fatty acid oil in the mixture may be from 9: 1 to 1: 9. The best mixtures are obtained in a ratio of 9: 1 to 5: 5. First, the mixed oil is heated until all crystals are melted. The liquid is cooled to create nuclei, and the crystals are then grown to a size and shape that allows for efficient separation. The separation and purification of the solids in the liquid phase is the last stage of the process.

The crystallization of the oil mixture is carried out in a crystallizer with a tubular design, which has a separate cooling jacket. The crystallizer must have a high cooling surface to oil capacity ratio and a high heat exchange coefficient. The crystalliser must be equipped with a stirrer, the design of which must be such as to enable continuous melting of the crystals leaving the heat exchanger. This is especially critical when the temperature is low. During cooling, the crystallite size should preferably be controlled to a suitable polymorph and should be of generally uniform size-this allows for ease of filtration. Oils and fats have complex triacylglycerols that crystallize either alone or in mixtures depending on cooling conditions. Various types of polymorphs such as alpha, beta and beta' crystals are also formed. These different forms of crystals have different properties with respect to melting point and filterability. These crystalline forms may change from one form to another depending on the cooling conditions. During the formation of mixed polymorphs, these mixed polymorphs tend to cause dendrite attachment of the crystals, thereby causing filtration problems and thus the oil quality differs in composition. The object of the present invention is to obtain crystals of the β' form having a regular shape and size and to remove some of the hard-to-melt triglycerides to finally obtain the desired composition. The filtration must be carried out under cooling conditions, preferably at least 10 ℃ below ambient temperature. The filter cloth should be of a suitable size so that crystals do not leak during filtration.

According to the invention, the IV of the olein obtained from palm oil and SBO in a ratio of 9: 1 is from 69 to 80, whereas the IV of the olein ranges from 81 to 96 when the ratio of palm oil and SBO is 7: 3. The IV of the olein obtained from palm stearin and SBO in a ratio of 7: 3 is between 77 and 99.

Examples

The following illustrates the process by which the oil is obtained by the mixing and fractionation process and the oil thus obtained.

Example 1

Palm oil was heated to 65 ℃ to 80 ℃ to ensure that all crystal history was removed from memory. Mixing soybean oil, sunflower oil or corn oil with palm oil at a ratio of 9: 1, wherein palm oil is in a higher ratio. The mixing of the oil at these temperatures must be continued until a homogeneous mixture is obtained. Fractionation was carried out at 20 ℃, 10 ℃ and then 8 ℃. The first fraction obtained at 20 ℃ was filtered and the oil was subsequently cooled to the next temperature until crystals having the composition determined in table 4 were obtained. The filtration of the oil product is effected by means of a membrane filter press at least 4 bar. As for the ratio of saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid, the saturated acid is 0.5 to 1.0, the monounsaturated fatty acid is 1.0 and the polyunsaturated fatty acid is 0.4 to 0.6.

Table 1: essential fatty acids in olein from a mixture of palm oil and unsaturated oil (9: 1)

	C14	C16	C18	C18-1	C18-2	C18-3	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids	IV
											8℃
Palm oil SFO	0.8	25.8	3.2	46.9	22.2	0.5	0.6	1.0	0.5	79.8
											Palm oil to SBO	0.8	27.6	3.1	45.8	20.2	1.7	0.7	1.0	0.4	78.5
Palm oil CO	0.8	27.6	2.9	46.2	21.1	0.7	0.7	1.0	0.5	77.8
											10℃
Palm oil SFO	0.9	28.1	3.3	45.3	21.4	0.2	0.7	1.0	0.5	76.3
											Palm oil to SBO	0.8	29.0	3.2	44.5	20.0	1.7	0.7	1.0	0.4	77.0
Palm oil CO	0.9	28.3	3.0	44.5	21.8	0.4	0.7	1.0	0.5	76.8
											20℃
Palm oil SFO	0.8	33.3	4.1	42.6	17.9	0.6	0.9	1.0	0.4	68.9
											Palm oil to SBO	0.9	33.4	4.0	42.3	17.3	1.4	0.9	1.0	0.4	69.8
Palm oil CO	0.8	32.4	3.8	43.1	17.8	0.7	0.9	1.0	0.4	69.0

Example 2

Palm oil was mixed with soybean oil, sunflower oil or corn oil at a ratio of 7: 3 and fractionated at 20 deg.C, 10 deg.C and then 8 deg.C as in example 1. The composition of the liquid fraction is shown below. The compositions obtained under these conditions have a ratio of monounsaturated fatty acids of approximately 1, whereas the ratio of saturated fatty acids to polyunsaturated fatty acids is less than 1. The ratio of saturated fatty acids to monounsaturated fatty acids to polyunsaturated fatty acids may be from 0.6 to 1.0, or from 0.7 to 1.0.

Table 2: essential fatty acids in olein from a mixture of palm oil and unsaturated oil (7: 3)

	C14	C16	C18	C18-1	C18-2	C18-3	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids	IV
											8℃
Palm oil SFO	0.7	23.6	3.7	38.2	33.3		0.7	1.0	0.9	90.1
											Palm oil to SBO	0.7	23.1	3.2	37.2	32.9	2.8	0.7	1.0	1.0	95.7
Palm oil CO	0.7	23.8	3.0	39.0	31.8	0.8	0.7	1.0	0.8	90.2
											10℃
Palm oil SFO	0.7	22.6	3.4	38.4	34.4	0.2	0.7	1.0	0.9	92.7
											Palm oil to SBO	0.7	26.8	3.4	37.6	30.5	1.0	0.8	1.0	0.9	87.4
Palm oil CO	0.7	23.0	3.0	38.9	32.0	0.8	0.7	1.0	0.8	90.5
											20℃
Palm oil SFO	0.7	29.7	3.9	36.8	28.6	0.2	0.9	1.0	0.8	81.3
											Palm oil to SBO	0.7	29.1	3.8	36.1	28.0	2.2	0.9	1.0	0.8	84.8
Palm oil CO	0.7	28.3	3.6	37.8	27.6	0.8	0.9	1.0	0.8	82.0

Example 3

Palm stearin is heated to at least 10 ℃ above its melting point and held at that temperature to ensure complete melting of the previous crystal history. It is then mixed with soybean oil, sunflower oil or corn oil in a ratio of 7: 3 and fractionated at 20 deg.C, 10 deg.C and then 8 deg.C. The composition of the finished oil is shown in table 3. The ratio of saturated fatty acid to monounsaturated fatty acid to polyunsaturated fatty acid is (0.5 to 1.0) to 1.0 to (0.3 to 1.2).

Table 3: the main fatty acids in the olein extracted from the mixture of palm stearin and unsaturated oil (7: 3)

	C14	C16	C18	C18-1	C18-2	C18-3	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids	IV
											8℃
Palm stearin: SFO	0.8	23.2	2.5	55.7	16.6	0.3	0.5	1.0	0.3	77.3
											Palm stearin SBO	0.6	23.1	3.2	33.2	35.5	3.7	0.8	1.0	1.2	99.1
Palm stearin CO	0.6	20.6	2.7	36.8	38.0	0.6	0.6	1.0	1.0	98.5
											10℃
Palm stearin: SFO	0.6	20.8	3.5	35.3	39.1	0.1	0.8	1.0	1.1	97.9
											Palm stearin SBO	0.6	25.7	3.5	33.1	32.9	3.5	0.8	1.0	1.0	93.9
Palm stearin CO	0.6	24.0	2.6	36.0	35.5	0.6	0.8	1.0	1.0	93.5
											20℃
Palm stearin: SFO	0.6	26.8	4.0	34.6	33.2	0.2	0.9	1.0	1.0	87.4
											Palm stearin: SBO	0.6	29.2	3.9	33.1	29.4	3.0	1.0	1.0	1.0	86.7
Palm stearin CO	0.6	23.9	2.8	35.9	35.5	0.6	0.8	1.0	1.0	93.4

According to the invention, also another fraction of the oil-the more saturated part of the oil and the solid fraction-also known as stearin-is produced in the same way. Another part of the present invention is the composition of stearin which can be used in margarines and shortenings based on solid fat content. The stearin may be further fractionated to obtain more product.

Example 4

Palm stearin was produced by fractionation of a palm oil-unsaturated fatty acid (9: 1) mixture. The ratio of saturated fatty acid to monounsaturated fatty acid to polyunsaturated fatty acid is (1.2 to 1.7) to 1.0 to (0.3 to 0.5). The solids content distribution of the mixture fractionated at 10 ℃ to 8 ℃ is that of palm oil and therefore finds similar application to palm oil.

Table 4: the main fatty acids in the stearin extracted from the mixture of palm oil and unsaturated oil (9: 1)

	C14	C16	C18	C18-1	C18-2	C18-3	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids
										8℃
Palm oil SFO	0.9	42.7	4.6	37.5	13.6	0.4	1.3	1.0	0.4
										Palm oil to SBO	0.9	43.4	4.7	36.7	12.6	1.0	1.3	1.0	0.3
Palm oil CO	0.9	44.9	4.6	36.5	12.1	0.6	1.4	1.0	0.3
										10℃
Palm oil SFO	1.0	44.3	4.8	36.5	12.8		1.4	1.0	0.4
										Palm oil to SBO	0.9	46.8	4.9	34.6	11.2	1.0	1.5	1.0	0.3
Palm oil CO	1.0	44.9	4.7	35.5	12.7	0.2	1.4	1.0	0.4
										20℃
Palm oil SFO	1.0	47.0	4.8	34.1	12.0	0.5	1.5	1.0	0.4
										Palm oil to SBO	0.9	48.8	4.7	33.2	10.8	0.9	1.6	1.0	0.3
Palm oil CO	1.0	46.9	4.5	34.8	11.7	0.6	1.5	1.0	0.3

Table 5: SFC of stearin from PO/UO (9: 1)

Example 5

The solid fractions obtained by fractionation of the oil mixture at 20 deg.C, 10 deg.C and 8 deg.C showed a ratio of saturated fatty acids to monounsaturated fatty acids to polyunsaturated fatty acids of (1.1 to 2.0) to 1.0 to (0.5 to 0.8). These compositions and solids content distributions can be used in margarines and shortenings. These also have a solids content distribution close to that of palm oil and are therefore applicable where palm oil is used as the solid fat.

Table 6: the main fatty acids in the stearin extracted from the mixture of palm oil and unsaturated oil (7: 3)

	C14	C16	C18	C18-1	C18-3	C18-3	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids
										8℃
Palm oil: SFO (7: 3)	0.9	37.7	4.6	33.5	22.9		1.3	1.0	0.7
										Palm oil: SBO (7: 3)	0.9	40.2	4.8	32.4	20.3	1.4	1.4	1.0	0.7
Palm oil to CO (7: 3)	0.9	40.0	4.5	33.0	20.2	0.6	1.4	1.0	0.6
										10℃
Palm oil: SFO (7: 3)	0.9	39.4	4.9	33.0	21.6		1.2	1.0	0.7
										Palm oil: SBO (7: 3)	1.0	42.7	4.7	32.5	17.8	1.4	1.5	1.0	0.6
Palm oil to CO (7: 3)	0.9	42.1	4.7	32.4	18.5	0.6	1.5	1.0	0.6
										20℃
Palm oil: SFO (7: 3)	1.1	49.2	4.7	28.0	16.6	0.2	2.0	1.0	0.6
										Palm oil: SBO (7: 3)	1.1	49.2	5.0	28.0	15.2	1.5	2.0	1.0
Palm oil to CO (7: 3)	1.1	48.6	4.8	27.9	16.1	0.6	2.0	1.0	0.6

Table 7: SFC of stearin from PO/UO (7: 3)

Example 6

The novel stearin is obtained by fractionation of the mixture at 20 ℃, 10 ℃ and 8 ℃ in a ratio of saturated fatty acid to monounsaturated fatty acid to polyunsaturated fatty acid of from 1.5 to 2.0 to 1.0 to 0.6 to 0.9.

Table 8: the main fatty acids in the stearin extracted from the mixture of palm stearin and unsaturated oil (7: 3)

	C14	C16	C18	C18-1	C18-2	C18-3	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids
										8℃
Palm stearin: SFO	0.8	40.8	4.5	29.3	22.8	0.9	1.6	1.0	0.8
										Palm stearin SBO	0.9	43.7	4.6	28.3	20.0	1.9	1.7	1.0	0.8
Palm stearin CO	0.9	42.4	4.2	30.3	21.5	0.2	1.6	1.0	0.7
										10℃
Palm stearin/SDO	0.9	41.9	4.6	29.5	22.4	0.1	1.6	1.0	0.8
										Palm stearin SBO	0.9	43.6	4.6	28.1	20.0	1.9	1.7	1.0	0.8
Palm stearin CO	0.9	44.3	4.3	29.8	20.2	0.2	1.7	1.0	0.7
										20℃
Palm stearin: SFO	0.9	45.9	4.7	27.9	19.7	0.1	1.8	1.0	0.7
										Palm stearin SBO	1.0	48.4	4.7	26.3	17.2	1.6	2.0	1.0	0.7
Palm stearin CO	0.9	47.8	4.4	28.1	17.9	0.2	1.9	1.0	0.7

Table 9: SFC of stearin from PS/UO (7: 3)

Example 7

Polyunsaturated fatty acids are generally lower in composition than saturated oils, with saturated fatty acids being higher in both and monounsaturated fatty acids being 1.0. Table 10 shows the liquid fraction of the oil mixture in a ratio of 9: 1 as it was further cooled. The liquid fraction of the oil mixture fractionated at 20 ℃ can be cooled again to give a fractionated fraction at 8 ℃ having the following type of oil composition ratios. The ratio of the components is (0.8-1.1) to 1.0 to (0.3-0.6).

Table 10: liquid fraction re-extracted from palm oil/unsaturated oil mixture (9: 1) liquid fraction

Liquid fraction	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids	IV
					PO∶SFO	0.9	1.0	0.5	77
PO∶SBO	0.8	1.0	0.5	76
					PO∶CO	0.8	1.0	0.5	76

Example 8

The liquid fraction of the oil mixture in a ratio of 7: 3 is shown below as it was further cooled to 8 ℃. In this example, the monounsaturated fatty acids were kept at 1.0 and the ratio of saturated fatty acids to polyunsaturated fatty acids was below 1.0, with the saturated fatty acids being the lower of the two. The range is (0.6 to 0.9) to 1.0 to (0.7 to 1.0).

Table 11: palm oil/unsaturated oil mixture (7: 3) solid fraction re-fractionated liquid fraction

Liquid fraction	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids	IV
					PO∶SFO	0.7	1.0	0.9	91
PO∶SBO	0.8	1.0	0.9	93
					PO∶CO	0.7	1.0	0.9	89

Example 9

This example shows fractionation of the solid fraction obtained by fractionation of a 7: 3 oil mixture at 20 ℃. The solid fraction is heated to 75 ℃ to 80 ℃ until all crystals are melted. The oil is then cooled to 50 ℃, held for 30 minutes to 1 hour and then further cooled to 30 ℃. It was kept for 3 hours and then the crystals were filtered. The liquid fraction of the process had the composition as determined in Table 12, with a ratio of monounsaturated to polyunsaturated fatty acids close to 1.0, and slightly lower saturated fatty acids. The range is (0.6 to 0.9) to 1.0 to (0.9 to 1.2).

Table 12: palm stearin/unsaturated oil mixture (7: 3) solid fraction re-fractionated liquid fraction

Liquid fraction	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids	IV
					PS∶SFO	0.7	1.0	1.1	98
PS∶SBO	0.8	1.0	1.1	97
					PS∶CO	0.8	1.0	1.0	93

Example 10

This example shows the situation when the following oil mixed with sunflower oil in a 7: 3 ratio is cooled to the following temperatures. Oils are available in which the composition of saturated and polyunsaturated fatty acids is similar to that of some olive oils. The composition of the liquid fraction obtained is almost close to that of olive oil 1 of this example. For saturated, monounsaturated and polyunsaturated acids, the percentage of fatty acids is 16% to 25%, 50% to 60% and 13% to 20%.

Table 13: olein from PS: SFO (7: 3) at 8 ℃

	Saturated fatty acid%	Monounsaturated fatty acid%	Polyunsaturated fatty acid%
				Oil extract	23	58.7	16.6
Olive oil 1	16	66	16
				Olive oil 2	13	75	9

Example 11

In this example, a fraction suitable for children's milk fat formulations is obtained, derived from some mixtures, with an oleic acid content of 28% to 46% and a palmitic acid content of 18% to 28%.

Table 14: essential fatty acids in olein from a mixture of palm oil and unsaturated oil (9: 1)

	C14	C16	C18	C18-1	C18-2	C18-3	Saturated fatty acid	Monounsaturated fatty acid	Polyunsaturated fatty acids
										8℃
Palm oil SFO	0.8	25.8	3.2	46.9	22.2	0.5	0.6	1.0	0.5
										Palm oil to SBO	0.8	27.6	3.1	45.8	20.2	1.7	0.7	1.0	0.4
Palm oil CO	0.8	27.6	2.9	46.2	21.1	0.7	0.7	1.0	0.5
										10℃
Palm oil SFO	0.9	28.1	3.3	45.3	21.4	0.2	0.7	1.0	0.5
										Palm oil to SBO	0.8	29.0	3.2	44.5	20.0	1.7	0.7	1.0	0.4
Palm oil CO	0.9	28.3	3.0	44.5	21.8	0.4	0.7	1.0	0.5

While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purposes of illustration, it will be apparent to those skilled in the art that: the invention is capable of other embodiments and its several details are capable of modifications in various obvious respects, all without departing from the basic principles of the invention.

Claims (22)

1. A mixing and fractionation process for obtaining an oil composition, the process comprising the steps of:

(a) mixing palm oil, palm olein or palm stearin with an unsaturated oil having an oleic acid content of more than 20% and a linoleic and linolenic acid content of more than 30% in a predetermined ratio to form a mixture, wherein the ratio of palm oil, palm olein or palm stearin to the unsaturated oil is from 9: 1 to 1: 9;

(b) heating the mixture at a temperature of 50 ℃ to 75 ℃ until all crystals melt;

(c) cooling the liquid obtained from step (b) for 4 to 24 hours to generate crystal nuclei and obtain a mixture of oil and crystals, wherein the crystals have a proper size and shape so that the oil and the crystals can be efficiently separated; and

(d) separating the mixture of oil and crystals to obtain an oil composition,

wherein the oil composition comprises saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids, and the ratio of saturated fatty acids to monounsaturated fatty acids to polyunsaturated fatty acids is 1: 1.

2. The process of claim 1, wherein in step (d) the mixture of oil and crystals is separated using a low or high pressure filter press.

3. The method of claim 1, wherein the ratio of the palm oil, palm olein or palm stearin to the unsaturated oil is from 9: 1 to 5: 5.

4. The process of claim 1 wherein the unsaturated oil is soybean oil, sunflower oil, corn oil, canola oil or rapeseed oil.

5. The method of claim 1, wherein the oil composition is used as a salad oil or a cooking oil.

6. The method of claim 1, wherein the resulting oil composition is used in a milk fat formulation.

7. A process according to claim 1, wherein the obtained stearin is used in margarine and shortening.

8. An oil composition which remains in a transparent liquid state at 15 ℃, obtained by a process for obtaining an oil composition, comprising the steps of:

(a) mixing palm oil, palm olein or palm stearin with an unsaturated oil having an oleic acid content of more than 20% and a linoleic and linolenic acid content of more than 30% in a predetermined ratio to form a mixture, wherein the ratio of palm oil, palm olein or palm stearin to the unsaturated oil is from 9: 1 to 1: 9;

(b) heating the mixture at a temperature of 50 ℃ to 75 ℃ until all crystals melt;

(c) cooling the liquid obtained from step (b) for 4 to 24 hours to generate crystal nuclei and obtain a mixture of oil and crystals, wherein the crystals have a proper size and shape so that the oil and the crystals can be efficiently separated; and

(d) separating the mixture of oil and crystals to obtain an oil composition,

wherein the oil composition comprises saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids, and the ratio of saturated fatty acids to monounsaturated fatty acids to polyunsaturated fatty acids is 1: 1.

9. The oil composition of claim 8 wherein the mixture of oil and crystals is separated using a low or high pressure filter press.

10. The oil composition of claim 8, wherein the ratio of the palm oil, palm olein, or palm stearin to the unsaturated oil is from 9: 1 to 5: 5.

11. The oil composition of claim 8 wherein the unsaturated oil is soybean oil, sunflower oil, corn oil, canola oil or rapeseed oil.

12. The oil composition of claim 8, wherein the oil composition is used as a salad oil or a cooking oil.

13. An oil composition as claimed in claim 8, wherein the resulting oil composition is used in a milk fat formulation.

14. An oil composition as claimed in claim 8, wherein the obtained stearin can be used in margarines and shortenings.

15. The process of claim 1 wherein the crystallization of the oil mixture is carried out in a crystallizer having a high cooling surface to oil volume ratio and a high heat exchange coefficient.

16. The process of claim 1, wherein the liquid resulting from step (b) is cooled from a temperature above the melting point of the oil to a temperature of from 8 ℃ to 20 ℃.

17. The process of claim 1, wherein in step (c), the crystal size is controlled to be a suitable polymorph and to be of generally uniform size to allow for ease of filtration.

18. The method of claim 1, wherein step (d) comprises filtration at a temperature of at least 10 ℃ below ambient temperature.

19. The oil composition of claim 12 wherein the oleic acid content is from 28% to 46% and palmitic acid content is from 18% to 28%.

20. The oil composition of claim 12, wherein palmitic acid, oleic acid and linoleic acid are within the requirements of infant fat and milk secreted from lactating mothers.

21. A process as claimed in any one of claims 2, 4 to 7 and 15 to 18, wherein the ratio of palm oil, palm olein or palm stearin to the unsaturated oil in step (a) is from 9: 1 to 5: 5.

22. The oil composition of any one of claims 9, 11-14 and 19-20, wherein the ratio of the palm oil, palm olein or palm stearin to the unsaturated oil in step (a) is from 9: 1 to 5: 5.