TW201629030A - Recovery of tocopherols/tocotrienols, glycerine, sterols and fatty acid esters from vegetable OIL distillate and the process thereof - Google Patents

Abstract

A process for recovering tocotrienols/tocopherols from vegetable oil distillate comprising the steps of esterifying the vegetable oil distillate with an alcohol in the presence of an acid catalyst to convert the fatty acids contained therein to produce an esterified mixture comprising fatty acid esters, thereby reducing fatty acid content in the oil to less than 3% by weight; distilling the esterified mixture for separating and removing the fatty acid esters therefrom; transesterifying the distilled mixture with an alcohol in the presence of a basic catalyst for converting glycerides present therein to fatty acid esters and glycerine, forming a transesterified mixture comprising glycerine and fatty acid esters; purifying the transesterified mixture to substantially remove glycerine therefrom; and distilling the purified mixture to substantially remove fatty acid esters, producing a composition comprising a predetermined concentration of tocotrienols/tocopherols.

Description

Recovery procedure for recovery of tocopherol/tocotrienol, glycerol, sterol and fatty acid esters from vegetable oil distillates

The present invention relates to valuable components in the recovery of vegetable oil distillates from a refinery. Further, the present invention relates to the use of multiple steps of esterification, distillation and transesterification, and recovery of high quality tocotrienols/tocopherols, sterols, and selective recovery of glycerol from palm oil distillates and Free fatty acids present in the ester form.

In the past few years, natural vegetable oils such as palm, palm kernel, rice bran, soybean, sunflower, canola, rapeseed, cottonseed, safflower and corn oil have been considered to contain high levels of ingredients beneficial to human health. These beneficial ingredients include, but are not limited to, tocopherols, tocotrienols, carotenoids, and steroids.

Tocopherols and tocotrienols are valuable ingredients in vegetable oils because they have antioxidant capacity and provide protection and prevent Cell damage in the brain, tumors, and various types of cancer, as well as assisting in repairing damaged cells. The unique molecular structure of tocotrienols further reveals cholesterol-lowering characteristics that help maintain a healthy cardiovascular system. Specifically, tocotrienols can help lower the concentration of vascular cholesterol by removing cholesterol accumulated in the arteries. Carotenoids are natural pigments synthesized by plants, which appear in yellow, orange or red colors. Among all carotenoids, α-carotene, β-carotene, and β-zeaxanthin are precursors of vitamin A (retinol) or interchangeably regarded as provitamin A, and serve as a source of vitamin A. Other carotenoids such as lutein, lycopene and zeaxanthin cannot be converted to vitamin A, but they are of particular importance because they are good antioxidants.

On the other hand, phytosterols are thought to block the absorption of cholesterol and reduce the concentration of blood cholesterol. Since phytosterols are almost identical to cholesterol, they compete with each other for absorption by the small intestine. However, phytosterols are not easily absorbed by the body, and they appear to block dietary cholesterol, thereby reducing blood cholesterol levels and reducing the risk of coronary heart disease. Some research literature also pointed out that phytosterols are characterized by anti-cancer, anti-inflammatory, anti-atherosclerosis and anti-oxidation.

In view of the above, it is desirable to extract or recover these beneficial ingredients from natural vegetable oils. A large proportion of tocotrienols and tocopherols are typically lost in various distillation streams during the recovery of these components. These distilled gas streams typically contain more than 0.1% by weight (or 1000 ppm) of fertility Trienol/tocopherol. However, these distilled gas streams also contain high free fatty acid concentrations above 10% by weight. Not only free fatty acids, other ingredients such as sterol esters, monoglycerides, ditriglycerides, triglycerides, glycerol, etc. can also be present in the distillation gas stream. Therefore, in order to obtain a composition having concentrated tocotrienol/tocopherol, these undesired impurities must be removed from the oil distillate.

Many recycling techniques have appeared in the past, such as solvent extraction, solvent partial separation, ion exchange resin treatment, and chromatography. However, these techniques have a number of disadvantages, including low yields, significant degradation of the components to be extracted throughout the process, and the use of organic carcinogenic solvents. Therefore, there is a need for an improved method for recovering tocotrienols/tocopherols.

The present invention provides an improved process for isolating tocotrienols/tocopherols from palm oil distillates while recovering free fatty acids in the form of glycerol and esters. In order to further improve the quality of the recovered component, an acidic esterification reaction is carried out in the pretreatment step of the present invention before the recovery of the tocotrienol/tocopherol, followed by a transesterification reaction to remove the fatty acid present therein.

One of the objects of the present invention is to provide a process for separating tocotrienols, tocopherols and sterols from palm oil distillates, and simultaneously recovering free fatty acids in the form of glycerol and esters.

Another object of the present invention is to provide a further transesterification The method of using an acidic esterification reaction as a pretreatment step to reduce the fatty acid content in the natural oil prior to the reaction, thereby improving the quality of the composition recovered or separated from the natural oil.

Another object of the present invention is to provide a method for separating and recovering tocotrienol/tocopherol and optionally other components, such as glycerol and sterols, which are not degraded or modified throughout the process.

Still another object of the present invention is to provide a multiple distillation step for post-treatment to increase the purity of the contemplated composition.

At least one embodiment of the present invention, which wholly or partially describes a process for recovering tocotrienol/tocopherol from a vegetable oil distillate, the process comprising: distilling the vegetable oil with an alcohol in the presence of an acidic catalyst The esterification reaction converts the fatty acid in the vegetable oil distillate to produce an esterified mixture containing the fatty acid ester, thereby reducing the fatty acid content in the vegetable oil distillate to less than 3% by weight; Distilling to separate and remove fatty acid esters in the esterification mixture to form a distillation mixture; transesterification of the distillation mixture with an alcohol in the presence of a basic catalyst to convert the glyceride in the distillation mixture Forming fatty acid esters and glycerol to form a transesterified mixture containing glycerol and fatty acid esters; purifying the transesterified mixture to substantially remove glycerol from the transesterified mixture to form a purified mixture; and subjecting the purified mixture to distillation, substantially removing and purifying Fatty acid esters in the mixture, producing tocotrienol/sheng containing a predetermined concentration The composition of the tocopherol.

In a preferred embodiment of the invention, the vegetable oil distillate is a palmitic fatty acid distillate or any vegetable oil distillate containing more than 10% by weight of the fatty acid in the total composition.

According to the previous examples, the vegetable oil distillate is subjected to esterification, distillation, transesterification and purification prior to further distillation. Preferably, the esterification reaction is carried out in the presence of an acidic catalyst, and the acidic catalyst may be hydrochloric acid, acetic acid, sulfuric acid or citric acid, and the transesterification reaction is carried out in the presence of a basic catalyst, and the basic catalyst may be sodium methoxide. Or potassium methoxide.

The aforementioned purification step refers to centrifugation or gravity settling to remove glycerol from the autorotation ester mixture.

In another preferred embodiment of the present invention, the method provided by the present invention further comprises the step of washing the esterification mixture or the purified mixture to remove the catalyst, unreacted alcohols and other impurities, followed by washing. The esterification mixture is heated to reduce the residual moisture content of the mixture to less than 0.07% by weight.

A further preferred embodiment of the present invention provides for the recovery of tocotrienol/tocopherol from a vegetable oil distillate, which further comprises the step of recovering sterols from the composition. The composition is subjected to alcohol treatment and the resulting mixture is cooled, and finally the recovered sterols are presented in crystalline form.

Preferably, the alcohol used in the esterification, transesterification or sterol recovery step may be any one of methanol, ethanol, propanol and butanol or a combination thereof.

It is to be understood by those skilled in the art that the present invention <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; It is noted that the following description of the preferred embodiments of the invention is not intended to be exhaustive or limiting.

It will be apparent to those skilled in the art that the present invention, in the <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; A more detailed description. It is noted that the following description of the preferred embodiments of the invention is intended to be illustrative and not restrictive.

The term "tocotrienol/tocopherol" or "tocopherol/tocotrienol" as used in the specification refers to any one or a combination of tocotrienol and tocopherol.

The present invention relates to a process for recovering tocotrienol/tocopherol from a vegetable oil distillate from a refinery which involves esterification, distillation, transesterification and further distillation. The method provided by the present invention selectively recovers sterols, glycerol, and free fatty acids in the form of esters.

It should be clear to those of ordinary skill in the art of the present invention. The vegetable oil distillate referred to in the present specification preferably contains a component of tocotrienol/tocopherol, sterol ester, fatty acid, monoglyceride, diglyceride, and triglyceride, wherein fertility The trienol/tocopherol accounts for 0.1% to 0.5% by weight of the total composition, while the content of the fatty acid in the total composition is more than 10% by weight.

According to a preferred embodiment of the present invention, the present invention recovers tocotrienol/tocopherol from a vegetable oil distillate, the step comprising: esterifying the vegetable oil distillate with an alcohol in the presence of an acidic catalyst, converting the vegetable oil The fatty acid in the distillate produces an esterified mixture containing fatty acid esters to reduce the fatty acid content in the vegetable oil distillate to less than 3% by weight; the esterification mixture is distilled to separate and remove the ester The fatty acid esters in the mixture, finally forming a distillation mixture; in the presence of a basic catalyst, the transesterification reaction is carried out on the distillation mixture using an alcohol to convert the glyceride in the distillation mixture into fatty acid esters and glycerol to form a transesterified mixture comprising glycerol and a fatty acid ester; purifying the transesterified mixture to substantially remove glycerol from the transesterified mixture to form a purified mixture; and subjecting the purified mixture to distillation to substantially remove fatty acids from the purified mixture The ester is finally produced into a composition containing a predetermined concentration of tocotrienol/tocopherol.

A preferred embodiment of the present invention discloses esterification of a vegetable oil distillate containing tocotrienol/tocopherol in the presence of an alcohol and an acidic catalyst, thereby converting a fatty acid present in the oil to a fatty acid alkane a base ester, which in turn forms a glyceride, a fatty acid alkyl ester, a sterol ester, and a tocopherol/fertility The esterification mixture of the triene phenol reduces the fatty acid content to less than 1%. Preferably, the alcohol used in the esterification reaction is a lower alkyl alcohol such as methanol, ethanol, isopropanol and butanol, while hydrochloric acid, phosphoric acid, citric acid or other suitable acid can be As an acidic catalyst. It should be clearly understood that the ratio of the acidic catalyst to the lower alkyl alcohol in the esterification solution (that is, the mixed solution of the acidic catalyst and the alcohol) is from 0.005 to 5:1.

In a preferred embodiment of the invention, the acidic esterification reaction is carried out at a temperature of from 5 ° C to 90 ° C for from 0.5 hours to 6 hours, and may be stirred or not stirred during the reaction, but stirring is preferred.

Preferably, after the acidic esterification reaction has been carried out, the entire esterification mixture is heated, preferably by vacuum evaporation or by a falling film evaporator in the art to substantially remove excess methanol from the mixture. This evaporation step is carried out at a temperature of from 30 ° C to 60 ° C for from 1 hour to 6 hours. The ratio of methanol removed to the esterified mixture (ie, acidic catalyst, alcohol and oil distillate) is 0.05 to 0.166:1.

Next, the resulting esterified mixture is washed with direct current water or countercurrent water to substantially remove excess acidic catalyst, unreacted alcohols that may be present, and other impurities such as sterol esters. Hot water or cold water can be used in this step, but water having a temperature of from 40 ° C to 80 ° C is preferably used. In order to ensure that the effect of removing catalysts, alcohols and other impurities from the esterification mixture is optimized, the washing step is repeated until the pH of the esterification mixture reaches a range of 6 to 8.

Due to the washing step, the moisture content in the esterification mixture will therefore increase. Therefore, in order to carry out the subsequent reaction steps, it is necessary to specifically reduce the moisture content in the esterification mixture to less than 0.07% by weight. Preferably, the moisture in the washed ester mixture is removed in a dry manner, whereby the washed ester mixture is heated at a temperature of from 35 ° C to 80 ° C for 0.5 to 10 hours under normal atmospheric pressure. Thereby the moisture in the ester mixture evaporates.

Next, the dried ester mixture is subjected to distillation, wherein the distillation step is preferably carried out at a lower than normal atmospheric pressure (also referred to as vacuum distillation). This distillation step involves more than one distillation tube to produce a first concentrated distillate containing fatty acid alkyl esters and a second concentrated distillate containing tocotrienol/tocopherol. In a preferred embodiment of the invention, the distillation is carried out in two successively arranged distillation tubes which are reacted at an atmospheric pressure of 0.01 to 1 kPa and at a temperature of 120 to 180 °C. Most of the fatty acid alkyl esters, unreacted fatty acids, and low boiling materials are separated from the esterification mixture, and the separated distillate is presented as a top stream of the first fractionator. The remaining material is then passed from the first fractionator to the subsequent distillation tube in the form of a residual stream to further separate the fatty acid alkyl esters in the esterification mixture. From the subsequent distillation tube, the fatty acid alkyl ester and the fatty acid that may be present are substantially separated, thereby producing a bottoms stream, or separating the distilled esterification mixture mentioned in the above description, wherein the bottom stream contains the total composition 1% to 5% tocotrienol/tocopherol.

In a more preferred embodiment of the invention, the esterification mixture is sent to a tube for drying prior to distillation to further reduce moisture to less than 0.01% by weight.

According to a preferred embodiment of the present invention, the distilled esterified mixture is subjected to a transesterification reaction in the presence of an alcohol and a basic catalyst to convert the glyceride in the esterified mixture into fatty acid esters and glycerin. Further, a transesterified mixture is formed which contains glycerin, fatty acid esters, tocotrienol/tocopherol, and other impurities such as sterol esters and glycerides. The alcohol used in the transesterification reaction is preferably a lower alkyl alcohol such as methanol, ethanol, isopropanol or butanol, and the basic catalyst may be sodium methoxide or potassium methoxide. It will be understood by those of ordinary skill in the art that the ratio of the distilled esterified mixture to the transesterification solution (mixture of basic catalyst and alcohol) is from 0.5 to 10:1.

Preferably, the transesterification reaction is carried out at a temperature of from 5 ° C to 90 ° C for from 0.5 to 6 hours, and the reaction may be carried out with or without stirring, but stirring is preferred. More preferably, the water vapor is removed by heating before the transesterification reaction to evaporate the water vapor, thereby reducing the moisture in the first distillate to less than 0.20% by weight.

Further in accordance with a preferred embodiment of the invention, the transesterified mixture is purified by isolating the glycerol in the transesterified mixture. The transesterified mixture can be subjected to centrifugation or gravity sedimentation to produce an ester-rich portion (or "purified compound") and a glycerin-rich portion having a glycerol-rich portion of 20% to 40% by weight. Fractional glycerin.

The glycerin-rich portion is neutralized with, for example, hydrochloric acid, acetic acid or sulfuric acid to convert excess alkaline catalyst into salts, which can be easily separated from the glycerol to produce 75% to 90% by weight. glycerin.

The purified mixture obtained from the foregoing step is preferably washed with direct current water or countercurrent water to remove excess catalyst and possibly unreacted alcohols and other impurities such as sterols. Hot water or cold water can be used in this step, but it is preferred to heat the water from a temperature of 40 ° C to 80 ° C to carry out a washing step. As with the aforementioned washing step, it is preferred to repeat the washing of the ester-rich portion until the pH of the ester-rich portion is lowered to the range of 6 to 8.

After the washing step is completed, the moisture in the purified mixture is thus increased, and in order to further carry out the subsequent process, it is necessary to reduce the moisture content therein to less than 0.07% by weight. By heating the purified mixture for 0.5 to 10 hours, the temperature is raised from 35 ° C to 80 ° C to substantially remove the moisture therein.

Following the water gas reduction or removal step, the purified mixture obtained is subjected to distillation to recover tocotrienol/tocopherol. It is worth noting that the distillation referred to herein is similar to the distillation mentioned above in this specification. Specifically, the purified mixture is subjected to vacuum distillation in two successively arranged distillation tubes, the first distillation tube is reacted at an atmospheric pressure of 0.01 to 1 kPa and at a temperature of 120 to 180 ° C, and the other distillation tube is at atmospheric pressure. The reaction is carried out at a pressure of 0.01 to 3 kPa and at a temperature of 120 ° C to 180 ° C. Fatty acid in the first distillation tube The esters and other low-boiling components are mainly recovered in the form of distillates, while the unrecovered components are discharged as residual streams, which are then sent to the next distillation tube to further separate the remaining streams. Fatty acid esters. Most of the fatty acid esters are again separated from the next distillation tube as a distillate. At the same time, a residual stream rich in tocotrienol/tocopherol is produced, wherein the tocotrienol/tocopherol comprises from 5% to 35% by weight. It is worth noting that this residual stream can also be referred to as a "distilled transesterified mixture."

In a preferred embodiment of the invention, the purified mixture can be heated or the purified mixture can be sent to a dryer to further reduce the moisture content to less than 0.01% by weight prior to distillation.

However, one of ordinary skill in the art will appreciate that to produce a higher purity gas stream or a desired percentage by weight of a tocotrienol/tocopherol-containing gas stream, the distilled transesterified mixture can be subjected to another distillation. Step or more distillation steps. The distilled transesterified mixture can be selectively recovered into the distillation tube.

Another preferred embodiment of the invention discloses that a distillation gas stream can be obtained in the distillation step, the distillation gas stream comprising primarily fatty acid esters which can be further processed or sold directly to supply the needs of the global market.

Further in accordance with a preferred embodiment of the present invention, the tocotrienol/tocopherol-rich distilled transesterified mixture can be further subjected to processing steps. Preferably, a lower alkyl alcohol such as any one or a combination of methanol, ethanol, propanol and butanol is added to the distilled transesterified mixture to separate and present Sterols in crystalline form. The resulting mixture was continuously stirred and cooled at a temperature of -30 ° C to 0 ° C for 12 hours to 3 days to finally form a crystalline sterol. This mixture is then subjected to solid-liquid separation to remove the crystalline sterol. Preferably, the mixture is centrifuged to produce an upper layer liquid and a bottom layer liquid.

The bottom liquid containing the sterol crystals is further subjected to evaporation by heating or other drying means.

It should be clearly understood that the supernatant obtained from centrifugation contains 30% to 90% by weight of tocotrienol/tocopherol. The supernatant liquid may be further heated to evaporate or remove some of the alcohol present in the supernatant liquid to form a composition containing tocotrienol/tocopherol at a desired concentration. It will also be apparent to those skilled in the art that the composition may also include other compounds such as squalene, sterol, and CoQ10.

Although the present invention has been disclosed above by way of example, it is not intended to limit the invention. Anyone having ordinary knowledge in the field can make some changes and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

Claims (18)

A method for recovering tocotrienol/tocopherol from a vegetable oil distillate, the method comprising: esterifying the vegetable oil distillate with an alcohol in the presence of an acidic catalyst, and converting the vegetable oil distillate a fatty acid, producing an esterified mixture containing fatty acid esters, thereby reducing the content of fatty acids in the vegetable oil distillate to less than 3% by weight; distilling the esterified mixture to separate and remove the esterified mixture The fatty acid esters to form a distillation mixture; the transesterification reaction is carried out on the distillation mixture using an alcohol in the presence of a basic catalyst to convert the glyceride in the distillation mixture into fatty acid esters and glycerin, Forming a transesterified mixture comprising glycerol and a fatty acid ester; purifying the transesterified mixture to substantially remove glycerol from the transesterified mixture to form a purified mixture; and subjecting the purified mixture to distillation to substantially remove the purified mixture The fatty acid esters in the form produce a composition containing a predetermined concentration of tocotrienol/tocopherol. The method of claim 1, further comprising the step of washing the esterification mixture to remove the catalyst, unreacted alcohols and other impurities, and then heating the washed esterification mixture to reduce the The residual moisture content of the mixture is less than 0.07% by weight. The method of claim 1, further comprising the step of washing the purified mixture to remove the catalyst, not The alcohol and other impurities are then applied, and the washed transesterified mixture is then heated to reduce the residual moisture content of the mixture to less than 0.07% by weight. The method of claim 1, wherein the glycerin in the transesterified mixture is removed by centrifugation or gravity settling during the purification step. The method of claim 1, further comprising recovering sterols from the composition. The method of claim 1 or 5, wherein the recovery of the sterols is carried out by treating the composition with an alcohol and cooling the subsequently formed mixture to produce crystalline sterols. The method of claim 2, wherein the washing step is a washing step of direct current water or countercurrent water. The method of claim 2, wherein the washing step is carried out using water heated to 40 ° C to 80 ° C. The method of claim 2, wherein the washed mixture is heated for 0.5 to 10 hours and the temperature is between 35 ° C and 80 ° C. The method of claim 9, wherein the washed mixture is heated for 0.5 to 10 hours. The method of claim 1, wherein the step of subjecting the esterification mixture to distillation is carried out in two sequentially arranged distillation tubes at a temperature of from 120 ° C to 180 ° C and a pressure of from 0.01 to 1 kPa. The method of claim 1, wherein the step of distilling the purified mixture is carried out in two successively arranged distillation tubes, wherein one of the distillation tubes is at a temperature of from 120 ° C to 180 ° C and a pressure of from 0.01 to 1 kPa. Under the operation, another distillation tube is in the temperature The temperature is from 120 ° C to 180 ° C and the pressure is operated at 0.01 to 3 Pa. The method of claim 1, further comprising the step of heating the mixture of esters or placing the mixture of the esters in a dryer to further reduce the moisture content to less than 0.01% by weight. The method of claim 1, further comprising the step of heating the purified mixture or placing the purified mixture in a dryer to further reduce the moisture content to less than 0.01% by weight. The method of claim 1, wherein the basic catalyst is sodium methoxide or potassium methoxide. A method according to any one of the preceding claims, wherein the alcohol is any one or combination of methanol, ethanol, propanol and butanol. The method of claim 1, wherein the acidic catalyst is hydrochloric acid, acetic acid, sulfuric acid or citric acid. The method of claim 1, wherein the vegetable oil distillate is a palmitic fatty acid distillate or any vegetable oil distillate having a fatty acid content greater than 10% by weight in the total composition.