CZ211095A3 - Process of refining oils containing triglycerides - Google Patents

Abstract

Glyceride oils (I) are refined by: (a) degumming; then (b) sepg. undissolved and non-centrifugable particles from the degummed (I). Step (a) is pref. by a conventional super-degumming. After step (a), the treated (I) is pref. held at less than 90 pref. less than 65 deg.C partic. room temp. to 40 deg.C for 0.5-5 hr. (to cause agglomeration of particles), or treated with an agglomerating agent (acid, H2O, hydratable phosphatide, hydrolysed phosphatide or mixts., esp. an alkali added at 0.01-100% of the free fatty acids). Step (b). Sepn. is by filtration, centrigation, sedimentation and/or decantation, pref. by microfiltration opt. after the addn. of an adsorbent and/or absorbent for the material to be removed.

Description

Process for refining triglyceride-containing oils

Field of the invention

The invention relates to a process for the refining of triglyceride-containing oils, in particular to a process for refining, one step of which consists in the dephosphatization.

BACKGROUND OF THE INVENTION

Oils containing triglycerides, especially of vegetable origin, for example soybean oil, rapeseed oil, sunflower oil, safflower oil, cottonseed oil and the like, are valuable raw materials in the food industry. These oils can be obtained in crude form usually from seeds and beans by compression and / or solvent extraction.

Said oils mainly consist of triglyceride components. However, they contain such large amounts of other components including phosphatides (gum or mucilaginous substances), viscous substances, partial glycerides, aliphatic acids, dyes and also small amounts of metals. Depending on the intended use of the oil, these impurities may have an adverse effect on stability, especially on storage, on the taste and color of the resulting products. For this reason, refining is required in which phosphatides and other impurities are removed from the crude oils to the highest possible degree.

Usually, the first stage of refining glyceride oils consists of so-called mucus removal, i.e. phosphatide removal. By this term is meant any processing of the oil which results in the removal of mucilaginous substances and other components. In conventional procedures of this type

It has now been found that although the oil may appear to be crystal clear after removal of the mucilaginous components, it still contains some undissolved remaining parts, for example hydrated phosphatides, which cannot be removed by simple centrifugation, but these particles can be removed by direct microfiltration or any by other suitable separation after subjecting the dephosphatized oil to conditions which cause agglomeration and / or further precipitation of the undissolved phosphatides and the particles containing them, for example, the oil may be maintained at a suitable temperature for some time with the addition of agglomerating agents. removal of these remaining phosphatides may result in an amount of phosphorus remaining below 15 ppm and in some cases below 10 or even below 5 porn. A suitable method for removing this proportion of undissolved phosphatides, also suitable for technical scale, is microfilter filtration with a suitable orifice diameter and suitable defeat.

It is an object of the present invention to provide a novel process for refining triglyceride-containing oils. This process consists in that after the slime-free oil stage, the oil is treated in a separation stage to remove undissolved and initially non-centrifugal particles from the oil.

SUMMARY OF THE INVENTION

The present invention provides a process for the refining of triglyceride-containing oils, characterized in that it comprises:

(ii) the oil is maintained at room temperature to 40 ° C to agglomerate the undissolved particles; and (iii) the formed particles are discarded.

Essential for refining according to the invention is the prior ripening of oil containing mucilaginous triglycerides. This can be done by any conventional method including the hydration of phosphatides, it is desirable to reduce the amount of residual phosphorus to a level of 5 to 250 ppm.

Throughout the application, the term slime deprivation refers to any process for the treatment of glyceride-containing oils in which water is added to the oil as such or with prior or subsequent or simultaneous addition of chemicals such as acids and / or bases such that at least of the non-glyceride components, especially the phosphatides, hydrate and then the insoluble hydrated material is separated by centrifugation or filtration to a residual phosphorus value of 5 to 250 ppm. Suitable processes for the removal of mucilaginous components are disclosed, for example, in British Patent Specification No. 1,565,569, US Patent Specifications Nos. 4,240,972 and 4,276,227, and European Patent Specification No. 195,991.

In the simplest form of the process, a relatively small amount of water is added to the triglyceride-containing crude oil, 0.2-5%, preferably 0.5-3% by weight, and then the phosphatide-containing sludge is removed by centrifugation. This procedure is well known in the art and its description can already be found in textbooks.

A more improved process has been described in U.S. Pat. No. 4,049,636. This process consists in dispersing effective amounts of concentrated acid or anhydrides thereof in a crude oil or optionally in an oil treated as described above, and then in the oil so treated. disperses an appropriate amount of water. The resulting aqueous sludge is separated from the oil after heating the oil-acid-water mixture for at least 5 minutes to a temperature of not more than 40 ° C.

To reduce the amount of phosphorus up to a range of 20 to 50 ppm, the crude oil is preferably treated with a concentrated citric acid solution at 70 to 90 ° C for 10 to 20 minutes. Water is then added in an amount of 0.2 to 5, preferably 0.5 to 3% by weight. The mixture is then cooled either before or after the addition of water to a temperature below 40%, preferably below 25 ° C. In order to ensure optimal hydration of the hydratable phosphatides in the oil, the mixture is maintained at this temperature for more than 1 hour, preferably 2 to 4 hours.

Depending on the amount of non-hydratable phosphatides, a certain amount of hydratable phosphatides as described in U.S. Pat. No. 4,162,260 may be added depending on the amount of non-hydratable phosphatides as described in U.S. Pat. No. 4,584,141. The phosphatide-containing sludge is then removed from the oil by centrifugation. Preferably, just prior to centrifugation, the mixture is heated to 50-80 ° C.

After this step (including sludge removal), the oil is further processed to remove the remaining fraction of undissolved phosphatides, which are present as very small particles with a diameter below 0.05 to 10 microns depending on the separation process and its conditions.

G

A suitable and preferred method for removing phosphatide residues is to filter the oil through a microfilter with a suitable pore diameter.

The process according to the invention therefore consists in the refining of oils containing glycerides after removal of the mucilaginous components by filtering the oil through a microfilter with an average pore diameter suitable for reducing the phosphorus residue below 15 ppm.

In order to reduce the phosphorus to this level, the filter apertures should have a diameter below 5 microns. A further advantageous reduction of the phosphorus content below 10 or up to 5 porn can be achieved by using a microfilter whose apertures have a mean diameter below 0.5 microns, preferably in the range of 0.1 to 0.3 microns.

Agglomeration can be initiated and / or increased by subjecting the oil to conditions where particles of material that are not dissolved in the oil or aggregates of undissolved particles are formed, for example by lowering the temperature or adding agents that promote particle formation and / or promote agglomeration of insoluble particles. Such materials are, for example, the hydratable phosphatides of U.S. Pat. No. 4,162,260 or the hydrolyzed phosphatides of U.S. Pat. No. 4,584,141. For the addition of the base, the equivalent of 0.01 to 100% of the aliphatic acids found in oil, deionized. Preferably, an equivalent of 0.05 to 50% of the free acids in the oil is added. Depending on the addition of these agents and the agglomeration time, the temperature may be selected or the agglomeration time may be shortened at certain selected temperatures.

Separation step (may optionally include addition of an absorbent or adsorbent for the undissolved particles to be removed. Examples of adsorbent agents include bleaching clays, activated carbon-containing materials, cellulose-containing materials such as Arbocel. and aluminosilicates such as Trisyl.

Further measures which favor the agglomeration may be further removal or any other separation process to remove undissolved particulate material from the oil.

Advantageously, a more sophisticated method of removing mucilaginous components is used to make it possible to reduce the agglomeration time and also to use higher temperatures.

Preferably, the agglomeration is carried out at the same temperature as the removal of the mucilaginous components.

Undissolved particles or agglomerates can be removed by filtration, microfiltration, centrifugation, settling and decantation. After removal of the particles, the refining of the oil having the remaining phosphorus content, for example below 15 ppm, preferably below 10 ppm, or even below 2 or 5 ppm, can be continued by using any refining process to provide the desired parameters of the resulting oils. For example, alkaline refining, bleaching and odor removal can be used. A particularly preferred process is physical refining, so that the whole process then consists of removing the mucilaginous components, reducing the remaining phosphorus content below 15 ppm, bleaching and deodorizing and thus does not involve the use of bases. In some cases, bleaching may also be omitted.

the low phosphorus content below 13 to below 5 ppm, which can be achieved by the invention, has a beneficial effect on the consumption of bleaching agents, which increases refining efficiency and reduces environmental pollution when the bleach consumption is too high.

The following examples illustrate the process according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Crude maize germ oil is freed from the spleen components as follows:

1)

2)

3)

4) the crude oil is mixed with 0.07% citric acid monohydrate (as a 50% solution) at 85 ° C, after 20 minutes 1.6% water is added, the mixture is cooled to 25 ° C and the hydration is allowed to proceed in total The sludge is separated from the oil at 65 ° C using a separating centrifuge.

Then, the resulting mucilaginized oil is subjected to filtration on five Milipore microfilters having a hole diameter in the range of 1.20 to 0.22 microns. The following results were achieved:

residual phosphorus in ppo

after the removal of phosphatides, without filtration 21.6 filter s holes 1.20 / Ua 15.2 filter s holes 0.80 / µm 16.6 filter s holes 0.65 / um 14.3 filter s apertures 0.45 µm 8.9 filter s holes 0.22 / µm 6.7

Example 2

Crude rapeseed oil was freed from the mucilaginous components as follows:

(1) 2% hydrolysed lecithin and 0,12% citric acid monohydrate as a 50% solution are added to the crude oil at 65 ° C;

2) 1.7% water was added after 20 minutes,

3) the mixture was cooled to 40 ° C, hydrated for a total of 3 hours, then

4) the sludge was removed from the oil at a temperature of 65 ° C using a separating centrifuge.

Microfiltration was then performed using five Milipore filters with openings ranging from 1.20 to 0.22 microns.

The following results were achieved:

residual phosphorus in ppo after removal of phosphatides, without filtration 20 filter with openings 1,20 um 10 filter with openings 0,80yUo γ filter with openings 0,65 / Um 8 filter with openings 0,45, u and 5 filter with openings 0,22 / Um 4

By way of comparison, the same filtration was carried out using rapeseed oil which was not depleted of mucilaginous constituents and oil which had been depleted of mucilaginous constituents but was then dried, meaning that it contained only the remaining phosphatides in the

unhydrated form. It was achieved the following results: residual phosphorus in ppm without de- with defosfa- phosphatization tidation and dried without filtration 41C 18 filter with 1.20 µm holes 430 18 filter with 0.65 µm holes 410 17 filter with 0.22 µm holes 420 17

These comparisons clearly show that the microfiltration according to the invention can only be successfully applied to oil which is free of mucilaginous constituents and still contains residual particles, for example phosphatides. Upon re-addition of water, undissolved particles were formed which could be removed by microfiltration as in the first five experiments described above.

Example 3

The crude rapeseed oil was freed from the mucilaginous components as described in Example 2. The oil obtained still contained phosphorus in an amount of 12 ppm.

Phosphatide-depleted rapeseed oil samples were subjected to different processing to facilitate agglomeration, the time and temperature of this treatment are shown in Table I. After this treatment, samples were subjected to microfiltration using filters with a hole diameter of 3.0, 1.2 and 0 , 45 micrometers. Table I also lists the remaining phosphorus values for the oil so treated.

From the results summarized in Table I, it is apparent that the undissolved particles formed clusters larger than 3 micrometers in 1.5 hours at relatively low processing temperatures. A particle size of approximately 3.0 microns already allows centrifugation of the formed clusters.

Table I (ppm)

Remaining phosphorus content

time temperature at pc mikrofi 1 -ta «S'— -U holes treatment (min) treatment (° C) 3.0 1,2 0.45 15 Dec 25 2 2 42 35 25 2 2 Z. 2 95 25 L2 Z 2 Z 2 15 Dec 65 6 5 2 35 65 5 5 3 95 65 5 5 3 15 Dec 90 5 7 3 35 90 5 7 4 95 90 10 11 4

Example 4

Soybean oil, free of degumming a conventional method using water, with a phosphorus content of 140 ppm was subjected to micro ^Rc fiitraci after two weeks storage at room temperature.

The following Table II shows the values of residual phosphorus which were obtained by filtration after removal of the mucilaginous components and after cooling and the same values that were obtained after two weeks of storage at room temperature.

Table II shows the results showing that, when microfiltration is performed at a further time from the removal of the mucilaginous components, the hydrated, non-centrifugal particles will form permanent clusters having a diameter greater than 1.2 microns. These clusters can then be removed from the oil by microfiltration.

Table II of filtration 2

Sequence hole size ( _/ um) instant pc 2 weeks

8.0 122 US 3.0 136 126 1,2 122 25 0.45 126 24

Example 5

The crude soybean oil was degummed as described in Example 2. The soybean oil thus treated still contained 12 ppm of phosphorus remaining.

Samples of the treated soybean oil were subjected to various processing to form clumps and then centrifuged for 10 minutes at 1000 rpm (corresponding to a critical diameter of 17 microns) and at 4000 rpm (corresponding to a critical diameter of 4.3 microns).

The results obtained are summarized in Table III below

Table III Aggregation time y min at 25 ° C residual phosphorus in ppm after centrifugation at 1CC0 rpm 4CC0 rpm C 5.9 3.4 30 4,5 5.4 75 3.1 2.3 120 - 2.2

It can be seen from Table III that the remaining phosphorus content can be reduced by a combination of prolonged agglomeration and centrifugation at high revolutions per minute.

Example 6

Crude sunflower oil was freed of mucilaginous components and waxy substances as follows:

(1) the crude sunflower oil was mixed with 1% hydrolysed lecithin and 0.08% citric acid monohydrate as a 50% solution at 65 ° C;

2) after 10 minutes the mixture was cooled to 18 ° C and 1.75% water was added,

3) the mixture was allowed to hydrate and crystallize for three hours, then

4) separating the sludge from the oil at 28 ° C using a separating centrifuge.

The sunflower oil thus treated was then subjected to microfiltration after an agglomeration time of 30 minutes at 25 ° C using a microfilter with a 0.2 micrometer orifice diameter (Microza, Asahi). The phosphorus content was reduced to 2 ppm from an initial level of 60 ppm.

The material was then directly subjected to odor removal for 2 hours at 240 ° C without any bleaching.

The organoleptic and storage properties of the sunflower oil thus refined were compared to sunflower oil from the same batch, but which was processed in a conventional manner using a base or subjected to physical refining.

The results obtained are summarized in Table IV below

Table IV

property refining principle physical refining refining by vyn; free aliphatic acids (%) 0.01 0.01 0.02 phosphorus content (ppm) O of 1 zl iron content (ppm) 0.03 0.02 0,0S chat index 0 weeks 6.6 6.4 6.6 3 weeks 6.3 5.8 6.3 6 weeks 6.2 5.8 5.6 9 weeks 6.2 6.0 5.7

Example 7

The crude rapeseed oil was freed from the mucilaginous components in a manner similar to Example 2. After the optional addition of the base (outside the process of the invention) and a standing time of 3-4 hours at room temperature (less than 30 ° C), Westfalia SAOOH 205) at normal back pressure and different flow rates. The results obtained are summarized in Table V below.

It is clear from Table V that the remaining, undissolved and initially non-centrifugable particles such as phosphatides can be effectively removed by centrifugation using the method of the invention.

Explanatory notes to the table:

sdg-conditions for slime removal, inlet temperature 80 to 85 ° C,

P - phosphorus content in the feed oil 1000 to 1100 ppm s

2.2% hydrolysed lecithin, addition of citric acid monohydrate, 0.12%, added water 2.2%, hydration time 3 hours, separation temperature 65 ° C.

The increase in baseline resistance in experiments II and III was due to contamination of the clarifier.

Table VI Try quantity conditions left over phosphorus (ppm) alifa- tické kyse- lazy(%) ?E (ppm) Ca / Mg / Na (ppm) C. (sdg) and flow 1 / h base added in% acid AND default obsah P po sdg 0 7.0 5 C 4.0 13 0 4.4 25 0 4.9 3C O 4.2 clay default obsah r pc sdg 15 Dec 7.7 0.85 0.1 1.3 / 0.6 / 140 7 15 Dec 1.0 0.81 40.1 0.3 / 0.1 / 4.3 17 15 Dec 1.9 0.83 40.1 0.2 / 0.1 / 7.9 53 15 Dec 0.7 0.83 <0.1 0.3 / 0.3 / 9.3 III default obsah r po sdg 25 10.3 - - - 23 25 0.7 0.78 0.4 1.3 / 0.4 / 16 40 25 2,0 0.78 0.4 1.0 / 2.2 / 13 105 25 1.4 0.80 0.3 0.9 / 0.2 / 6.5 125 25 1,2 0.75 1.0 0.9 / 0.2 / 33

ZasťEteíarfé

Claims (9)

1. A process for the refining of triglyceride-containing oils, characterized in that a sludge-free glyceride oil is used, the oil is maintained at room temperature to 40 DEG C. to agglomerate the undissolved particles, and the particulate material is admixed. separate provided that:. no acid or base is present during the agglomeration of the undissolved particles. The process according to claim 1, characterized in that it is based on triglyceride-containing oil from which the mucilaginous substances have been completely removed. A process according to claim 1 or 2, characterized in that the oil is maintained at a temperature of less than 40 ° C for 0.5 hours to 2 weeks. 4. A process according to any one of claims 1 to 3, characterized in that an agent is added to the oil to promote the formation of undissolved particles or agglomeration thereof. 5. The method of claim 4 wherein the agent is selected from the group of hydratable phosphatides, hydrolyzed phosphatides, and mixtures thereof. « 6. A process according to claims 1 to 5, wherein an adsorption agent for undissolved particles is added to remove the formed particles. Method according to claims 1 to 6, characterized in that the particles are separated by filtration, microfiltration, centrifugation, sedimentation and / or decantation. 8. The process of claims 1 to 7, wherein the oil is heated to a temperature of 50-80 [deg.] C. just prior to removal of the particles. A process for refining glyceride-containing oils, i. E (i) uses mucilage-free oil; and (ii) mucilage-free oil is subjected to microfiltration.