WO2011138957A1 - Method for purification of edible oil or fat - Google Patents

Abstract

Disclosed is a method for purifying an edible oil or fat, which enables the reduction in the contents of chlorine compounds each having a relatively low molecular weight, e.g., 3-monochloro-propanediol and ester compounds thereof, in the oil or fat. Specifically disclosed is a method for purifying an edible oil or fat, which is characterized by involving a step of heating the oil or fat in the presence of water while applying a pressure to the oil or fat, wherein water preferably has a subcritical state upon heating and is preferably contained in an amount of 25 to 400 parts by mass relative to 100 parts by mass of the oil or fat, and the heating step is preferably carried out in a closed container or a flow reactor.

Description

Method for refining edible oils and fats

The present invention relates to a method for purifying edible fats and oils.

Regardless of its origin, edible fats and oils are usually refined in the order of a degumming step, a deoxidizing step, a decoloring step, and a deodorizing step. By the refining process of these fats and oils, edible fats and oils with few impurities, low acid value, no coloration and no odor can be obtained. In addition, a dewaxing process is added to the above purification process when producing edible fats and oils that do not require the formation of fat crystals even at low temperatures, such as salad oil, or when fats and fats with a high wax content are used as raw fats and oils. May be.

The degumming step is a step of precipitating / separating and removing gums such as phospholipids dissolved in fats and oils by phosphoric acid treatment.
A deoxidation process is a process of neutralizing the free fatty acid contained in fats and oils and removing the produced soap.
The decoloring step is a step of removing the pigment component and other trace components with an adsorbent such as activated clay.
The deodorization step is a step in which water vapor is blown into fats and oils heated under reduced pressure, and volatile components are distilled and removed.

However, it is known that some impurities are also present in the edible fat obtained through the above-described purification process. For example, low volatility components that do not react with acids and alkalis and are not adsorbed by adsorbents cannot be removed sufficiently by the above purification process, and substances by-produced in the final deodorization process should also be removed. I can't.

An example of such a material that cannot be removed is a chlorine compound.
As a chlorine compound, for example, a part of agricultural chemicals and dioxin are famous, but since these are regulated in plant bodies and animal bodies which are raw materials for fats and oils, they are not usually contained in edible fats and oils.
Moreover, even if it exists, it is known that extraction and removal with supercritical carbon dioxide is effective for removing agricultural chemicals and dioxins in the production of edible fats and oils. (Patent Document 1)

However, according to recent knowledge, a relatively low molecular weight chlorine compound, for example, 3-monochloro-propanediol and its ester compound are contained in a small amount in purified edible oils and fats, compared to these chlorine compounds, It has been found that there is no effective way to remove it. (See Non-Patent Document 1)

The relatively low molecular weight chlorine compound contained in the edible fat is extremely small compared to the amount contained in the protein hydrolyzate obtained by acid hydrolysis of the protein, but is preferably removed.

In the production of the above-mentioned protein hydrolysates and amino acids, research on a method for removing a relatively low molecular weight chlorine compound is active, and as a method for removing the relatively low molecular weight chlorine compound, a supercritical carbon dioxide is removed. Extraction removal by carbon (for example, refer to Patent Document 2) and decomposition by alkali and heating (for example, refer to Patent Documents 3 and 4) have been proposed.

However, the method described in Patent Document 1 does not describe the effect on chlorine compounds having a relatively low molecular weight, and in addition, fats and oils are dissolved by carbon dioxide in a supercritical state. Has a problem that the yield of edible fats and oils is extremely poor.

In addition, the method described in Patent Document 2 is a method in which an oil-soluble component is extracted and removed from an aqueous amino acid solution or a powdered amino acid with carbon dioxide in a supercritical state, and a chlorine compound dissolved in the oil and fat by extraction. Therefore, it cannot be applied to a method of removing a chlorine compound dissolved in fats and oils.

Furthermore, when the methods described in Patent Documents 3 and 4 are applied to fats and oils, it is necessary to add an alkaline solution again to the refined fats and oils. There is a problem that decolorization and deodorization must be performed.

Thus, a method for removing relatively low molecular weight chlorine compounds in edible fats and oils, such as 3-monochloro-propanediol and its ester compounds, has not been developed at present, and is applicable to general foods and drinks. Since it is impossible to apply the method, a new method for refining edible fats and oils is required.

JP 2003-009777 A Japanese Patent Laid-Open No. 02-244361 JP 07-330793 A Japanese Patent Laid-Open No. 02-133506

Therefore, an object of the present invention is to provide a method for purifying edible fats and oils that can reduce relatively low molecular weight chlorine compounds in edible fats and oils, such as 3-monochloro-propanediol and ester compounds thereof.

The present inventors have been variously studied to achieve the above object, but instead of vacuum distillation performed in the deodorizing step of the purification of edible oils and fats, when the edible fats and oils are brought into contact with water vapor while being pressurized completely. It has been found that the content of relatively low molecular weight chlorine compounds such as 3-monochloro-propanediol and its ester compounds in the edible fats and oils obtained can be significantly reduced.
That is, this invention is made | formed based on the said knowledge, and provides the refinement | purification method of edible fat and oil characterized by including the process heated while pressurizing fat and oil in presence of water.

According to the method for purifying edible fats and oils of the present invention, the content of relatively low molecular weight chlorine compounds such as 3-monochloro-propanediol and its ester compound in edible fats and oils is significantly reduced without reducing the yield of fats and oils. Thus, it is possible to obtain an edible oil and fat with a significantly reduced content of 3-monochloro-propanediol and its ester compound.

Below, the refinement | purification method of the edible fat of this invention is demonstrated in detail based on the preferable embodiment.
The edible oil and fat used in the present invention is not particularly limited. For example, palm oil, palm kernel oil, coconut oil, corn oil, olive oil, cottonseed oil, soybean oil, rapeseed oil, rice oil, sunflower oil, safflower oil, beef tallow , Milk fat, pork fat, cacao butter, shea fat, mango kernel oil, monkey fat, iripe fat, fish oil, whale oil and other vegetable fats and oils, and one or two selected from hydrogenation, fractionation and transesterification The processed fats and oils which performed the above process can be used. In the present invention, these edible fats and oils can be used alone or in combination of two or more.

The water used in the present invention is not particularly limited, and for example, tap water, mineral water, ion exchange treated water, and distilled water can be used. In this invention, these water can also be used individually or can also be used in combination of 2 or more type.

The method for purifying edible fats and oils of the present invention includes a step of heating the fats and oils while applying pressure in the presence of the water.
Therefore, a process for heating the oil and fat while pressurizing it in the presence of water will be described below.

In the present invention, when the oil is heated while being pressurized, the higher the heating temperature and the higher the pressure, the higher the removal rate of 3-monochloro-propanediol and its ester compound. Therefore, it may be a condition above the supercritical point of water (374 ° C. and 22 MPa), that is, a condition in which water is in a supercritical state. Although the removal rate of diol and its ester compounds is high, triglycerides are decomposed, antioxidant components and antioxidants originally contained in oils and fats are decomposed, and further, fats and oils in supercritical water As a result, the yield of edible fats and oils decreases, so that the temperature is as high as possible and the temperature is below the supercritical point of water, that is, the water during heating is in a subcritical state. The conditions are preferred.

Here, in the method for purifying edible fats and oils of the present invention, the subcritical state refers to a temperature at a temperature lower than the supercritical point of water and a high temperature and high pressure state equal to or higher than the saturated vapor pressure at that temperature. The preferred heating temperature and pressure conditions in this case will be described. The heating temperature is preferably 150 to 370 ° C., more preferably 200 to 350 ° C., further preferably 200 to 300 ° C., and the pressure condition is preferably The pressure is 0.3 to 21 MPa, more preferably 1 to 20 MPa, and still more preferably 1 to 17 MPa. When the heating temperature is less than 150 ° C. or the pressurizing condition is less than 0.3 MPa, the removal rate of relatively low molecular weight chlorine compounds such as 3-monochloro-propanediol and its ester compound is lowered, and the heating temperature is 370 If the temperature exceeds ℃ or the pressure condition exceeds 21 MPa, the yield of fats and oils may be reduced.

In the method for purifying edible fats and oils of the present invention, the amount of water added (abundance) is preferably 25 to 400 parts by weight, more preferably 65 to 150 parts by weight with respect to 100 parts by weight of fats and oils. If the amount is less than 25 parts by mass, the removal rate of a relatively low molecular weight chlorine compound such as 3-monochloro-propanediol and its ester compound may be reduced, and if it exceeds 400 parts by mass, the yield of fats and oils may be reduced. is there.

The heating and pressurization according to the present invention can be performed in a sealed container or a flow reaction container.

The following examples can be given as specific methods for carrying out in a closed container.
Transfer fat and water to a sealable reaction vessel equipped with a heater with a pump, etc., seal the vessel, raise the temperature to a specified temperature with a heater, and confirm that the specified pressure condition is met at the set temperature Hold for a predetermined time.
In the method for purifying edible fats and oils of the present invention, the reaction time at the heating temperature and the pressurizing condition is preferably 2 to 40 minutes, more preferably 2 to 25 minutes, still more preferably 2 to 2 minutes when carried out in a closed container. 12 minutes.

And after the said heating and pressurization, Preferably water is removed. Examples of water removal methods include a method of cooling and returning the water to a liquid state, and then allowing it to stand for natural separation, a method of separating the center, and a method of extracting fats and oils with a solvent such as hexane or diethyl ether. Can.

The following examples can be given as specific methods for carrying out in a flow reaction vessel.
As an example of the apparatus for performing the flow-type reaction, a continuous processing apparatus including a high-pressure pump, a reaction vessel with a heater, a cooler, and a back pressure valve device may be mentioned. First, fats and oils and water are transferred to a reaction vessel with a heater by a high-pressure pump. In addition, it is preferable that oil and water and water are preheated separately or mixed and then preheated before being transferred to a reaction vessel with a heater in advance because the heating time can be shortened. It is preferable that oil and fat and water are preheated separately from the viewpoint that diglyceride by-products can be suppressed. The heating temperature in the preheating is preferably 60 to 350 ° C., more preferably 100 to 300 ° C., and most preferably within 10 ° C. above and below the set temperature of the reaction.
And it is made to retain for a predetermined time under preset temperature and pressure in a reaction container.
In the method for purifying edible fats and oils of the present invention, the reaction time at the heating temperature and the pressurizing condition is preferably 1 to 30 minutes, more preferably 1 to 20 minutes, and still more preferably when carried out in a flow reaction vessel. 1 to 15 minutes. In the case of a continuous reaction, the residence time is generally used as the reaction time.
Next, the mixture is cooled to a safe temperature and pressure by a cooler, and the reaction liquid that is a mixture of water and fat is recovered. The pressure in the reaction vessel is controlled by a back pressure valve device installed before or after the cooler, preferably after the cooler. And preferably, water is removed from the reaction solution. Examples of the water removal method include a method of standing and natural separation, a method of centrifuging, and a method of extracting fats and oils with a solvent such as hexane and diethyl ether.

As described above, the heating and pressurization of the present invention can be performed in either a sealed container or a flow-type reaction container. However, in the point that the preheating device and the back pressure valve device are not required and the equipment is simple, Although it is preferable to perform this, it is easy to insert a preheating device before the start of the reaction, so that the total reaction time can be shortened, and a refined fat with a low diglyceride content can be obtained in a short reaction time. It is preferable to carry out in a flow type reaction vessel.

As described above, the conventional oil and fat purification process consists of a degumming process, a deoxidation process, a decolorization process, and a deodorization process. , May be inserted in any part of the above-described purification process, and may be performed before the degumming process or after the deodorization process, but considering the possibility that the chlorine compound is generated in the deodorization process, It is preferable to carry out after the deodorizing step.

In addition, when performing the process heated while pressing in the presence of the water after the deodorization process, it is preferable to further perform the deodorization process after the heating process. In this case, a relatively low molecular weight chlorine compound, for example, 3-monochloro-propanediol and its ester compound, and their precursors are removed by the heating step while applying pressure in the presence of water. Therefore, the chlorine compound is not increased by this deodorizing step.

The obtained edible oils and fats are characterized by a relatively low content of chlorine compounds having a relatively low molecular weight, in particular, a very low content of 3-monochloro-propanediol and its ester compounds. The content of 3-monochloro-propanediol and its ester compound in general edible fats and oils varies depending on the type of edible fats and oils. However, in the case of refined fats and oils, it is usually about 0.5 to 5 ppm depending on the type of oil. In contrast, the content of 3-monochloro-propanediol and its ester compound in the edible fat refined by the purification method of the present invention is 0 to 3 ppm.

The edible oil / fat obtained by the purification method of the present invention can be used for the production of food and drink as in the case of general edible oil / fat. In that case, the resulting food or drink has a relatively low molecular weight chlorine compound content, particularly 3-monochloro-propanediol content, in comparison with food and drink using the edible fat obtained by the conventional purification method. And its ester compound content is reduced.

Examples of the foods and drinks include, for example, margarine, shortening, fat spread, flavored fat spread, dressing, mayonnaise, frozen dessert, oil for spray, oil for frying, oil for chocolate, oil for fats such as batter oil, Food and drink using confectionery bread materials such as flower paste, rice cake, Western confectionery, Japanese confectionery, bread, snacks, curry, stew, gratin, seasonings, instant cooked foods, processed livestock products, processed fishery products, processed vegetable products Product.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples.

Examples 1 to 3 and Comparative Example 1
Palm oil was used as an oil and fat, and the palm oil was degummed, deacidified, bleached, and deodorized by a conventional method to obtain purified palm oil (Comparative Example 1). A sample in which 1.0 g of this refined palm oil was placed in a SUS316 pipe having a length of 5 cm, an inner diameter of 1 cm and a thickness of 1.8 mm together with 1.0 g of water, the gas phase was replaced with nitrogen, and both ends were sealed with screw caps. Seven were prepared. These were heated in an oil bath at 150 ° C. for 180 minutes (Example 1), 200 ° C. for 10 minutes, 20 minutes and 40 minutes (Example 2), 250 ° C. for 10 minutes, 20 minutes and 40 minutes, respectively. Heated for a minute (Example 3). The pressure at the time of heating was 0.5 MPa in Example 1, 1.5 MPa in Example 2, and 4 MPa in Example 3, and water was in a subcritical state. Subsequently, these heated samples were cooled to 60 ° C., and a mixture of water and fat was separated into an oil phase and an aqueous phase by centrifugation at 3000 rpm for 15 minutes, and the oil phase was recovered.
In each of the obtained samples, 3-monochloro-propanediol and its ester compound in the oil phase were quantified in accordance with the Standard Methods C-III 18 (09) method of DGF (German Petroleum Institute). In this quantification method, after pretreatment of ester hydrolysis and derivatization with phenylboronic acid, 3-monochloro-propanediol is converted to a phenylboronic acid derivative, and quantification is performed by GC / MS. Table 1 shows the results.
In addition, the diglyceride content in the oil phase after the reaction was measured. This quantification was performed using HPLC according to AOCS “Ce 5c-93”. Table 2 shows the results.

From the results of Table 1 above, in Example 1, which is a reaction at 150 ° C. for 180 minutes, 3-monochloro-propanediol was reduced from 3.54 ppm to 2.37 ppm, whereas the temperature was raised to 200 ° C. In 2, it decreased to 0.98 ppm in 20 minutes, and after 40 minutes, became below the detection limit. In Example 3 where the reaction temperature was raised to 250 ° C., the reaction temperature decreased to 0.44 ppm in 20 minutes and was below the detection limit in 40 minutes. Thus, it can be seen that the amount of 3-monochloro-propanediol decreases in a shorter reaction time as the reaction temperature is higher and the pressure is higher.
Moreover, it can be seen from the results in Table 2 that the diglyceride content increases as the reaction time is extended and the reaction temperature is increased.

[Examples 4 to 11]
As in Example 1, refined palm (Comparative Example 1) was used as the oil and fat, and heat-pressed using a flow-type reaction vessel (SUS316 tube having a length of 16 cm, an inner diameter of 4 cm, and a thickness of 2.0 mm) as the reactor. Processed. In addition, the fats and oils were each heated to the preset temperature of the reaction by a preheating device before being transferred to the flow-type reaction vessel. Then, after mixing the heated fat and water at a mass ratio of 1: 1, a residence time of 5 minutes at 150 ° C. (Example 4), a residence time of 5 minutes at 200 ° C. (Example 5), and a residence time of 250 ° C. 5 minutes (Example 6), residence time 5 minutes at 270 ° C. (Example 7), residence time 10 minutes at 150 ° C. (Example 8), residence time 10 minutes at 200 ° C. (Example 9), 250 ° C. The residence time was 10 minutes (Example 10), and the treatment was performed at 270 ° C. for a residence time of 10 minutes (Example 11). The pressure at this time is 0.4 MPa in Example 4, 2.0 MPa in Example 5, 4.5 MPa in Example 6, due to the pressure difference between the high pressure pump and the back pressure valve device installed after the cooler. 7 was 6.0 MPa, Example 8 was 0.4 MPa, Example 9 was 2.0 MPa, Example 10 was 4.5 MPa, Example 11 was 6.0 MPa, and water was in a subcritical state. The heated sample is cooled to 60 ° C. with a cooler, and the reaction mixture, which is a mixture of water and fat obtained, is separated into an oil phase and an aqueous phase by centrifugation at 3000 rpm for 15 minutes, and the oil phase is recovered. did. The recovered oil phase was deodorized at 3-7 Torr and 230 ° C. for 1 hour. The amount of steam blown during this period was 2% (w / w) against oil.
The determination of 3-monochloro-propanediol and its ester compound in the oil phase and the measurement of the diglyceride content in each sample obtained were carried out in the same manner as in Example 1. The results are shown in Table 3.

From the results of Table 3 above, under the condition of a residence time of 5 minutes, 3-monochloro-propanediol was reduced from 3.54 ppm to 2.88 ppm at 150 ° C. (Example 4), whereas the temperature was 200 ° C. In Example 5 raised to 2.05 ppm, it decreased to 2.05 ppm, and in Example 6 raised to 250 ° C., it became 0.95 ppm, and in Example 7 raised to 270 ° C., it became 0.52 ppm. Thus, it can be seen that the amount of 3-monochloro-propanediol decreases as the reaction temperature increases and the pressure increases.
When the residence time was extended from 5 minutes to 10 minutes, 3-monochloro-propanediol decreased from 2.88 ppm to 2.68 ppm at 150 ° C. (Example 4) (Example 8), while In Example 5 (Example 5) (Example 9), 2.05 ppm was raised to 1.15 ppm, and further in 250 ° C (Example 6) (Example 10), 0.95 ppm was raised to 0.49 ppm and 270 ° C. In Example 7, 0.52 ppm became 0.3 ppm. Thus, it can be seen that when the reaction temperature is 200 ° C. or higher, the amount of decrease in 3-monochloro-propanediol is large.
Regarding the diglyceride content, almost no increase in the content was observed at all temperatures of 150 to 270 ° C. under the condition of a residence time of 5 minutes, but at 150 to 200 ° C. under the condition of a residence time of 10 minutes. The contents were almost the same at residence times of 5 minutes and 10 minutes, but at 250 to 270 ° C., a slight increase was observed at residence times of 5 minutes and 10 minutes.

Here, it can be seen by comparing the 3-monochloro-propanediol content (Table 1) and diglyceride content (Table 2) of Example 2 with the 3-monochloro-propanediol content and diglyceride content (Table 3) of Example 5. In addition, when a sealed container is used, the 3-monochloro-propanediol content is 1.95 ppm and the diglyceride content is 8.8% at 200 ° C. for 10 minutes. When used, the 3-monochloro-propanediol content at 200 ° C. for 10 minutes was 1.15 ppm, and the diglyceride content under the conditions was 7.8%, although the pressure was slightly higher than when a sealed container was used. -Monochloro-propanediol and diglyceride content are both low, and 3-monochloro-propanediol It can be seen that the reduction of the content is possible.
As can be seen from the comparison of the 3-monochloro-propanediol content (Table 1) and diglyceride content (Table 2) of Example 3 with the 3-monochloro-propanediol content and diglyceride content (Table 3) of Example 6. When a sealed container is used, the 3-monochloro-propanediol content is 0.74 ppm at 250 ° C. for 10 minutes and 0.44 ppm at 20 minutes, and the diglyceride content under these conditions is 8.8%, 13.8% On the other hand, when pre-heated and a flow-type reaction vessel was used, the 3-monochloro-propanediol content was 0.69 ppm at 250 ° C. for 10 minutes, and the diglyceride content under the conditions was 8.3%. Although the pressure is slightly higher than when using a container, the 3-monochloro-propanediol content and the diglyceride content are both low. While by-product of inhibition of 3-monochloro - it can be seen that it is possible to reduce the propanediol content.

[Comparative Example 2]
As in Example 1, refined palm (Comparative Example 1) was used as the fat and oil, and the same flow-type reaction vessel used in Examples 4 to 11 as the reactor (length 16 cm, inner diameter 4 cm, thickness 2.0 mm) SUS316 tube) and heated with pressurizing only the oil and fat without mixing water. The fats and oils were heated to 250 ° C. by a preheating device before being transferred to the flow type reaction vessel. And the process for 5 minute residence time was performed at 250 degreeC. The pressure at this time was 4.5 MPa due to the pressure difference between the back pressure valve device installed after the high pressure pump and the cooler. The heated sample was cooled to 60 ° C. with a cooler.
Quantification of 3-monochloro-propanediol and its ester compound in the oil phase and measurement of diglyceride content in the obtained sample were carried out in the same manner as in Example 1. The results are shown in Table 4.

From the results of Table 4 above, when heat treatment was performed while pressing oils and fats in an anhydrous state, the content of 3-monochloro-propanediol was the same as 3.54 ppm of Comparative Example 1 above, and 3-monochloro-propane It turns out that there is no reduction effect of diol.

Claims (8)

1. A method for purifying edible fats and oils, comprising a step of heating the fats and oils while applying pressure in the presence of water.
2. 2. The method for purifying edible fats and oils according to claim 1, wherein the water during heating is in a subcritical state.
3. 3. The method for purifying edible fats and oils according to claim 1 or 2, wherein the water is present in an amount of 25 to 400 parts by weight with respect to 100 parts by weight of the fats and oils.
4. The method for purifying edible fats and oils according to any one of claims 1 to 3, wherein the heating step is performed in a closed container.
5. The method for purifying edible fats and oils according to any one of claims 1 to 3, wherein the heating step is performed in a flow-type reaction vessel.
6. 6. The method for purifying edible fats and oils according to any one of claims 1 to 5, wherein preheated fats and oils are used.
7. Edible fats and oils obtained by the method for purifying edible fats and oils according to any one of claims 1 to 6.
8. A food or drink obtained using the edible oil or fat according to claim 7.