CN117757853A

CN117757853A - Process for preparing diglyceride

Info

Publication number: CN117757853A
Application number: CN202311542971.4A
Authority: CN
Inventors: 陈和盛; 刘多智; 童星
Original assignee: It Is A Health Technology Co ltd; Guangdong Haitian Innovation Technology Co Ltd
Current assignee: It Is A Health Technology Co ltd; Guangdong Haitian Innovation Technology Co Ltd
Priority date: 2023-11-20
Filing date: 2023-11-20
Publication date: 2024-03-26

Abstract

The application relates to a preparation method of diglyceride, which comprises the following steps: vegetable oil, water, lipase and glycerin are used as raw materials to prepare a crude diglyceride product; subjecting the crude diglyceride product to a first deodorization treatment, and collecting a heavy phase retentate; performing second deodorization treatment on the heavy phase trapped matters, and collecting light phase trapped matters; adding an adsorbent to the light phase retentate to adsorb residual byproducts to prepare diglyceride; wherein the temperature of the second deodorization treatment is higher than that of the first deodorization treatment, and the lipase is food grade lipase. According to the method, under the condition of no organic solvent, the food-grade lipase is adopted to prepare the crude diglyceride product through enzymatic transesterification, and then the physical mode of multi-stage molecular distillation is adopted to refine and purify aiming at the boiling point difference of different lipid structures in the crude diglyceride product, so that the high-purity diglyceride is obtained by further combining an inorganic physical adsorption technology, and the formation of trichloropropanol and glycidyl ester can be greatly reduced.

Description

Process for preparing diglyceride

Technical Field

The application relates to the fields of biochemical engineering and biotechnology, in particular to a preparation method of diglycerides.

Background

The diglyceride is a trace component of natural grease and an intermediate product of metabolism in a human body, and the dietary DAG can reduce fat accumulation, reduce blood lipid level, prevent cardiovascular and cerebrovascular diseases such as arteriosclerosis, coronary heart disease, stroke, cerebral thrombosis, obesity, fatty liver and the like, and has great help to improve the health level of the human body, so how to obtain the high-purity diglyceride is always a hot research topic in the industry.

The process for obtaining high purity diglycerides generally comprises three stages of preparation, refining and purification.

The preparation process of diglyceride mainly comprises three methods of high-temperature esterification, chemical synthesis and enzymatic transesterification.

The high-temperature esterification refers to the catalysis of fats and oils/fatty acids and glycerin to form glyceride reaction products under high-temperature conditions (No. 150 ℃) with or without a catalyst. For example, a patent application describes a purification preparation method and application of a high-purity conjugated linoleic acid glyceride compound, wherein the high-purity conjugated linoleic acid glyceride compound is prepared by reacting high-purity conjugated linoleic acid (or methyl ester and ethyl ester) with glycerol at an oil bath heating temperature of 150-250 ℃, and then two standard products or pure products with different substitution positions of high-purity linoleic acid diglyceride can be obtained by further separation. However, the above method requires a long exposure to high temperature, and promotes formation of trichloropropanol ester and glycidyl ester.

Chemical synthesis is to synthesize diglyceride through chemical reaction between various chemical matters. For example, a patent application discloses a chemical synthesis of 1, 2-diglycerides comprising the steps of: (a) Under the action of a proper catalyst, benzyl glycidyl ether reacts with fatty acid to obtain 1, 2-fatty acid-3-benzyloxy glyceride; (b) The 1, 2-fatty acid-3-benzyloxy glyceride is hydrogenated under the catalysis of palladium carbon to remove protective groups to obtain a crude product of 1, 2-fatty acid diglyceride, and the crude product can be recrystallized at low temperature to obtain high-purity (85-95%) 1, 2-fatty acid diglyceride with high yield (> 90%). For another example, a patent application discloses a chemical synthesis process for producing diacylglycerols comprising the steps of: the method comprises the steps of reacting in an organic solvent to obtain monosilylated glycerol, condensing monosilylated glycerol with fatty acid to obtain monosilylated diacylglycerol, deprotecting silyl groups of the monosilylated diacylglycerol to obtain crude diacylglycerol, and removing the monoacylglycerol and the fatty acid from the crude diacylglycerol by using a saturated hydrocarbon nonpolar solvent containing 6-8C and a dihydric alcohol polar solvent containing 2-4C to obtain the diacylglycerol with the purity of 95%. However, in the process of preparing diglyceride by chemical synthesis, a great deal of chemical structure and organic solvent are involved, so that the problem of environmental protection is serious, and the hidden danger of food safety exists.

Enzymatic transesterification refers to the reaction of fatty acids and glycerol in an organic solvent or solvent-free environment to form diglycerides and mixtures thereof using an enzyme preparation as a catalyst. For example, a patent application provides a process for producing diacylglycerols by reacting triglycerides with water and an enzyme to obtain a mixture containing diglycerides, and separating and purifying the mixture to obtain high-purity diglycerides (88.7-90.8%). For example, a patent application provides a process for preparing diglycerides by subjecting raw materials to an esterification reaction in an enzyme-packed column comprising an immobilized lipase preparation to obtain high-purity diglycerides (88.7 to 90.8%). For example, a patent application provides a process for producing diacylglycerol-rich oils or fats by esterification of glycerol fatty acids or alkyl esters thereof with immobilized enzymes to produce diglycerides having a purity of 91.8 to 94.8%. For example, a patent application provides a novel method for preparing diglyceride, which comprises adding raw materials into a reactor, adding lipase, performing enzymatic reaction, and purifying to obtain diglyceride with purity of 96-97%. For example, a patent application provides a variant, plasmid, recombinant strain of a partial glyceride lipase of Mucor malasseziae (Malassezia globosa), and a preparation method and application thereof, and the lipase hydrolyzes mixed partial glycerides to obtain diglyceride products with purity of more than 98%. For example, a patent application provides a prepared marine bacterium Malassezia restricta lipase MRL synthesized diglyceride enzyme and a preparation method thereof, which have good esterification activity, can efficiently catalyze glycerin and fatty acid to form monoglyceride and diglyceride, the content of the diglyceride in a product reaches 30% -50%, and the diglyceride in the high-purity grease obtained by molecular distillation of the product contains 80% -93% of diglyceride. Although the process for preparing diglycerides by enzymatic transesterification is expected to obtain diglycerides with higher concentration and purity, the enzyme preparation adopted in the preparation process is a novel non-food-grade enzyme preparation, and the food safety of the enzyme preparation is not substantially evaluated.

The refining and purifying process of diglyceride mainly includes three methods of molecular distillation, low-temperature crystallization and solid-phase adsorption separation and purification.

Cases of purification by molecular distillation are for example:

a patent application provides a method for synthesizing diglycerides using a bubble reactor, the method comprising the steps of: placing the immobilized enzyme on a bearing mechanism of the bubbling reactor; starting a hot bath mechanism to heat the reactor main body to 55-75 ℃; adding glycerin, fatty acid and water into a trough and preheating to 55-75 ℃, and putting the mixture into a reactor main body to initiate a synthesis reaction, wherein the crude glyceride layer is subjected to two-stage molecular distillation to obtain high-purity diglyceride, the distillation temperature of the first-stage molecular distillation is set to be 150-200 ℃, the pressure is 5.0Pa, free fatty acid is removed, the heavy phase separated by the distillation of the first-stage molecular distillation enters a second-stage molecular distillation, the temperature of the second-stage molecular distillation is set to be 190-200 ℃, the pressure is 1.0-5.0Pa, and the obtained diglyceride is further refined, and the high purity of the diglyceride is 91.42%. The above method limits the application because excessive high temperatures promote the formation of trichloropropanol and glycidyl esters during the process of high temperature molecular distillation.

A patent application provides a preparation method of high-purity diglyceride, which utilizes partial glyceride lipase to catalyze the reaction of a fatty acid donor and glycerin to synthesize a mixture containing diglyceride and monoglyceride, utilizes monoglyceride lipase to catalyze the reaction of monoglyceride in an oil phase and a hydroxyl donor to convert the monoglyceride and the hydroxyl donor into non-glyceride, then separates the non-glyceride and the diglyceride, and the concentration of the diglyceride can reach 67.5-99.6% after single-stage molecular distillation purification. In the method, partial diglyceride is hydrolyzed, so that the total recovery rate is reduced, and a certain consumption is formed for enzyme activity.

A patent application provides a process for producing diglycerides by combining an oil comprising at least one polyunsaturated fatty acid in the form of ethyl esters, free fatty acids, and/or combinations thereof, a lipase, and glycerol in water to produce diglycerides having high purity levels. The method adopts an ethanol solvent system to convert the triglyceride into diglyceride in the preparation process, and unreacted fatty acid and fatty acid ethyl ester have lower boiling points and can be removed by single-stage molecular distillation. However, the above method is difficult to ensure the safety of industrial production and is disadvantageous in green environmental protection.

Cases of purification using low temperature crystallization are for example: one patent application provides a transesterification synthesis method of diglyceride, which obtains a 1,2-DAG crude product through enzymatic transesterification, and then obtains the diglyceride of 1,2-DAG with the purity reaching 93-96% through 2 steps of mixing and low-temperature clean purification of the crude product, normal hexane and methanol. However, the method uses a large amount of organic solvents in the purification process, which can have adverse effects on food safety, industrial production safety and environmental protection.

Examples of the separation and purification using solid phase adsorption include: a patent application provides a method for rapidly separating triglyceride and diglyceride by using a florisil adsorption method, which uses mixed structural grease as a substrate, adsorbs the mixed structural grease on a florisil adsorbent, sequentially elutes and removes the triglyceride and the mixture of the diglyceride and the triglyceride, and finally repeatedly elutes and extracts the diglyceride by using diethyl ether to obtain the diglyceride with the purity of more than 96mol percent. The method uses a chromatographic separation technology of solid phase adsorption, a large amount of organic solvents such as normal hexane, diethyl ether and the like are needed to carry out elution analysis in the separation process, potential safety hazards and environmental protection exist, meanwhile, the solid phase needs to be scrapped after being used, and the industrial treatment cost for such waste products is high.

In conclusion, the conventional processes such as preparation, refining and purification of the high-purity diglyceride at present have certain technical limitations, and are not beneficial to large-scale popularization and application.

Disclosure of Invention

Based on the above, it is necessary to provide a preparation method of diglycerides, which can reduce the formation of trichloropropanol ester and glycidyl ester, is safe and environment-friendly, has low production cost, and is suitable for large-scale popularization and application.

The application provides a preparation method of diglyceride, which comprises the following steps:

vegetable oil, water, lipase and glycerin are used as raw materials to prepare a crude diglyceride product;

subjecting the crude diglyceride product to a first deodorization treatment, and collecting a heavy phase retentate;

subjecting the heavy phase retentate to a second deodorization treatment, and collecting a light phase retentate; and

adding an adsorbent to the light phase retentate to adsorb residual byproducts to produce diglycerides;

wherein the temperature of the second deodorization treatment is higher than that of the first deodorization treatment, and the lipase is food grade lipase.

In some of these embodiments, the temperature of the first deodorization treatment is 170 ℃ to 240 ℃ and the temperature of the second deodorization treatment is 270 ℃ to 310 ℃.

In some of these embodiments, the pressure of the first deodorization treatment is 0.07Pa to 200Pa, and the pressure of the second deodorization treatment is 0.07Pa to 200Pa.

In some embodiments, the ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is 2 or more.

In some of these embodiments, the feed flow rate of the first deodorization treatment is more than twice the feed flow rate of the second deodorization treatment.

In some of these embodiments, the step of adding an adsorbent to the light phase retentate to adsorb residual byproducts satisfies at least one of the following conditions:

(1) The temperature is 105-120 ℃;

(2) The vacuum degree is-92 KPa to-85 KPa;

(3) The adding amount of the adsorbent is 1% -5% of the weight of the light phase trapped substance;

(4) The treatment time is 20 min-30 min; and

(5) The adsorbent comprises one or more of neutral clay, magnesium silicate, activated carbon and silicon dioxide.

In some of these embodiments, the lipase comprises a first lipase and a second lipase, and the step of preparing the crude diglyceride product comprises:

mixing the vegetable oil and the water, and then adding the first lipase to perform a first reaction to prepare a first reaction product;

separating the first reaction product and collecting a first upper light phase;

mixing the first upper light phase with the glycerol, adding the second lipase, and performing a second reaction to prepare a second reaction product; the method comprises the steps of,

And separating the second reaction product, and collecting a second upper light phase to prepare the crude diglyceride product.

In some of these embodiments, the first reaction satisfies at least one of the following conditions:

(1) The mass ratio of the vegetable oil to the water is 1 (0.6-1.2);

(2) The addition amount of the first lipase in the first reaction is 2% -10% of the mass of the vegetable oil;

(3) The stirring speed of the first reaction is 250 rpm-500 rpm;

(4) The reaction temperature of the first reaction is 40-85 ℃; the method comprises the steps of,

(5) The reaction time of the first reaction is 12-48 h.

In some of these embodiments, the second reaction satisfies at least one of the following conditions:

(1) The molar ratio of the glycerin to the fatty acid contained in the first upper light phase is (0.5 to 0.8): 1, a step of;

(2) The addition amount of the second lipase in the second reaction is 1-10% of the mass of the first upper light phase;

(3) The stirring speed of the second reaction is 250 rpm-500 rpm;

(4) The reaction temperature of the second reaction is 40-60 ℃;

(5) The reaction time of the second reaction is 2-12 h; the method comprises the steps of,

(6) The reaction pressure of the second reaction is 0.05 KPa-1.5 KPa.

In some of these embodiments, the means for separating the first reaction product comprises: and filtering the first reaction product, collecting filtrate, and centrifuging the filtrate.

In some of these embodiments, the means for separating the second reaction product comprises: and filtering the second reaction product, collecting filtrate, and centrifuging the filtrate.

According to the preparation method, vegetable oil, water, lipase and glycerin are used as raw materials, under the condition of no organic solvent, food-grade lipase is adopted to prepare a crude diglyceride product through enzymatic transesterification, then first deodorization treatment and second deodorization treatment are sequentially carried out according to the boiling point difference of different lipid structures in the crude diglyceride product, a physical mode of multistage molecular distillation is adopted to carry out refining purification, and the problem of the increase of the content of residual byproducts such as trichloropropanol ester, glycidyl ester and the like caused in the high-temperature molecular distillation process is further solved by combining with an inorganic physical adsorption technology, so that the high-purity diglyceride is obtained.

Detailed Description

In order that the present application may be understood, a more complete description of the present application will be provided below in connection with the examples. This application may, however, be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

In the present application, the technical features described in an open manner include a closed technical scheme composed of the listed features, and also include an open technical scheme including the listed features.

performing second deodorization treatment on the heavy phase trapped matters, and collecting light phase trapped matters;

adding an adsorbent to the light phase retentate to adsorb residual byproducts to prepare diglyceride;

wherein the lipase is food grade lipase.

In some of these embodiments, the temperature of the second deodorization treatment is higher than the temperature of the first deodorization treatment. The components in the crude diglyceride product are separated in different deodorizing treatment processes according to the difference of boiling points, so that the diglyceride with high purity is more beneficial to be obtained.

Further, the temperature of the first deodorization treatment is 170 ℃ to 240 ℃, and the temperature of the second deodorization treatment is 270 ℃ to 310 ℃. It will be appreciated that the temperature of the first deodorization treatment may be, for example, but not limited to, 170 ℃, 190 ℃, 205 ℃, 220 ℃, 240 ℃, etc., and the temperature of the second deodorization treatment may be, for example, but not limited to, 250 ℃, 270 ℃, 295 ℃, 300 ℃, 310 ℃, etc.

Further, the pressure of the first deodorization treatment is 0.07Pa to 200Pa. It will be appreciated that the pressure of the first deodorization treatment may be, for example, but not limited to, 0.07Pa, 0.5Pa, 1Pa, 5Pa, 200Pa, etc.,

further, the pressure of the second deodorization treatment is 0.07Pa to 200Pa. It is understood that during the second deodorization treatment, the pressure of the second deodorization treatment may be, for example, but not limited to, 0.07Pa, 0.5Pa, 1Pa, 5Pa, 200Pa, and the like.

In some embodiments, the ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is 2 or more. It will be appreciated that the treatment of the crude diglyceride product is performed by first subjecting it to a first deodorization treatment, usually designated as 1 stage, followed by a second deodorization treatment, the number of stages of which is usually counted from 2 stages, the number of times of the second deodorization treatment may be one or more, and each time the second deodorization treatment is performed is counted as one stage, for example, the number of stages of the second deodorization treatment is 2 stages if only the second deodorization treatment is performed once, the number of stages of the second deodorization treatment is 3 stages if the second deodorization treatment is performed twice, the number of stages of the second deodorization treatment is 4 stages if the third deodorization treatment is performed, and so on. The larger the ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is, the more favorable the division and separation of components in the crude diglyceride product are, and the purity of the diglyceride is improved. Further, if the number of times of the second deodorization treatment is plural, the treatment temperature of each time is greater than the treatment temperature of the previous time, so that the component separation and purification of the crude product can be more effectively achieved.

In some of these embodiments, the feed flow rate of the first deodorization treatment is more than twice the feed flow rate of the second deodorization treatment. Impurities with lower boiling points are separated out by the first deodorization treatment, and under the condition of lower treatment temperature, the feed flow can be increased to improve the separation treatment efficiency.

In some of these embodiments, the temperature in the step of adding the adsorbent to the light phase retentate to adsorb residual byproducts is from 105 ℃ to 120 ℃. Under such conditions, the adsorbent is more favored to adsorb residual byproducts. It is understood that the adsorption temperature may be, for example, but not limited to, 105 ℃, 110 ℃, 120 ℃, and the like.

In the present application, the addition of the adsorbent to the light phase retentate after the second deodorizing treatment can further effectively adsorb and remove residual byproducts while avoiding the problem of grease color reversion caused by excessive oxidation.

In some of these embodiments, the vacuum level in the step of adding the adsorbent to the light phase retentate to adsorb residual byproducts is from-92 KPa to-85 KPa. The proper vacuum degree is kept, and the adsorption effect is better. It is understood that the vacuum level during the adsorption process may be, for example, but not limited to, -92KPa, -90KPa, -88KPa, -85KPa, and the like.

In some of these embodiments, the step of adding an adsorbent to the light phase retentate to adsorb residual byproducts comprises adding the adsorbent in an amount of 1% to 5% by weight of the light phase retentate. It is understood that the amount of adsorbent added may be, for example, but not limited to, 1%, 2%, 3%, 4%, 5% of the light phase retentate mass, and the like.

In some of these embodiments, the step of adding an adsorbent to the light phase retentate to adsorb residual byproducts is performed for a period of time ranging from 20 minutes to 30 minutes. It is understood that the processing time may be, for example, but not limited to, 20min, 22min, 25min, 28min, 30min, and the like.

In some of these embodiments, in the step of adding an adsorbent to the light phase retentate to adsorb residual byproducts, the adsorbent comprises one or more of neutral clay, magnesium silicate, activated carbon, and silica.

mixing vegetable oil and water, and then adding a first lipase to perform a first reaction to prepare a first reaction product;

separating the first reaction product and collecting a first upper light phase;

mixing the first upper light phase with glycerol, adding a second lipase, and performing a second reaction to prepare a second reaction product; the method comprises the steps of,

And separating the second reaction product, and collecting a second upper light phase to prepare a crude diglyceride product.

The preparation process of the diglyceride is free from adding any organic solvent, is very green and environment-friendly, ensures the production, namely the post-treatment safety, and adopts food-grade lipase for enzymatic transesterification, so that the product meets the requirements of food safety.

It is understood that lipases in this application include food grade immobilized or liquid specific or non-specific lipases. Further, lipases include, but are not limited to, lipozyme Calb and Lipozyme 435 of Candida antarctica, lipozyme TL 100L and Lipozyme TL IM of Thermomyces lanuginosus, lipozyme RM IM of Rhizomucor miehei, palatase 20000L, NS40086 and Eversa Transform 2.0FG of Aspergillus oryzae, and the like, but also other enzyme preparations of the same kind. The first lipase may be the same as or different from the second lipase.

It is understood that vegetable oils in this application include, but are not limited to, one or more of soybean oil, canola oil, peanut oil, corn oil, sunflower oil, sesame oil, camellia oil, linseed oil, olive oil, coconut oil, palm kernel oil, olive pomace oil, walnut oil, rice bran oil, rice oil, cottonseed oil, perilla oil, safflower oil, grape seed oil, pumpkin seed oil, peony seed oil, tea seed oil, eucommia seed oil, algae oil, krill oil, acer truncatum seed oil, shea butter, silybum seed oil, triacylglycerols, conjugated glycerol linoleate, samara oil, mera oil, tomato seed oil, amygdalus pedunculata oil, cornus macranth seed oil, and imperial oil.

Further, in the first reaction, the mass ratio of the vegetable oil to the water is 1 (0.6-1.2). It is understood that the mass ratio of vegetable oil to water may be, for example, but not limited to, 1:0.6, 1:0.8, 1:1.0, 1:1.2, and the like.

Further, in the first reaction, the addition amount of the first lipase in the first reaction is 2% -10% of the mass of the vegetable oil. It is understood that the amount of the first lipase added in the first reaction may be, for example, but not limited to, 2%, 5%, 8%, 10% and the like of the mass of the vegetable oil.

Further, in the first reaction, the stirring rate of the first reaction is 250rpm to 500rpm. It is understood that the agitation rate of the first reaction may be, for example, but not limited to, 250rpm, 325rpm, 400rpm, etc.

Further, in the first reaction, the reaction temperature of the first reaction is 40 to 85 ℃. It is understood that the reaction temperature of the first reaction may be, for example, but not limited to, 40 ℃, 55 ℃, 60 ℃, 85 ℃, and the like.

Further, in the first reaction, the reaction time of the first reaction is 12 to 48 hours. It is understood that the reaction time of the first reaction may be, for example, but not limited to, 12h, 18h, 22h, 24h, 48h, etc.

Further, in the second reaction, the molar ratio of glycerin to fatty acid contained in the first upper light phase is (0.5 to 0.8): 1. it will be appreciated that the molar ratio of glycerol to fatty acid contained in the first upper light phase may be, for example, but not limited to, 0.5:1, 0.75:1, 0.8:1, etc.

Further, in the second reaction, the addition amount of the second lipase in the second reaction is 1 to 10% of the mass of the light phase of the first upper layer. It is understood that the amount of the second lipase added in the second reaction may be, for example, but not limited to, 1%, 3%, 5%, 8%, 10% of the mass of the first upper light phase. Etc.

Further, in the second reaction, the stirring rate of the second reaction is 250rpm to 500rpm. It is understood that the stirring rate of the second reaction may be, for example, but not limited to, 250rpm, 325rpm, 400rpm, 500rpm, etc.

Further, in the second reaction, the reaction temperature of the second reaction is 40 to 60 ℃. It is understood that the reaction temperature of the second reaction may be, for example, but not limited to, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, and the like.

Further, in the second reaction, the reaction time of the second reaction is 2 to 12 hours. It is understood that the reaction time of the second reaction may be, for example, but not limited to, 2h, 4h, 12h, etc.

Further, in the second reaction, the reaction pressure of the second reaction is 0.05KPa to 1.5KPa. It is understood that the reaction pressure of the second reaction may be, for example, but not limited to, 0.05KPa, 0.4KPa, 0.8KPa, 1.1KPa, 1.5KPa.

In some of these embodiments, the means for separating the first reaction product comprises: the first reaction product is filtered, the filtrate is collected, and the filtrate is centrifuged.

Further, the centrifugation conditions include: the centrifugal speed is 3000 rpm-5000 rpm, and the centrifugal time is 8 min-12 min. It is understood that the centrifugation speed may be, for example and without limitation, 3000rpm, 4000rpm, 5000rpm, etc., and the centrifugation time may be, for example and without limitation, 8min, 10min, 12min, etc.

In some of these embodiments, the means for separating the second reaction product comprises: the second reaction product is filtered, the filtrate is collected, and the filtrate is centrifuged.

According to the method, the special grease, namely the diglyceride, is prepared under the condition that the food-grade lipase is limited in variety and specificity through the transesterification without an organic solvent, and the preparation process accords with the safety of food and industrial production, and is environment-friendly. The method is characterized in that the method aims at the difference of different lipid structure boiling points in the crude diglyceride product, the crude diglyceride product is purified by a physical mode of multistage molecular distillation, and residual byproducts generated at high temperature are subjected to physical adsorption to be degraded and removed, so that the diglyceride special grease component with high purity and low trichloropropanol and glycidyl ester content is finally obtained, and even the content of the trichloropropanol and the glycidyl ester impurities can be reduced to undetected levels. The method does not use chemical organic solvents in the whole process of preparation, refining and purification, adopts full biological and physical processing, and synchronously solves the problem of residual trichloropropanol ester and glycidyl ester in raw materials. The preparation of the high-purity special oil is realized through the conventional equipment and technology, the application of molecular distillation in the industry is enlarged, the preparation method has the multiple advantages of low additional investment, no use of organic solvents, full physical refining and purification and the like, and the preparation method is safe, low in cost and environment-friendly, and is suitable for large-scale popularization and application.

The preparation method of diglycerides of the present application is described in further detail below by way of specific examples. The following embodiments are more specific, and it is understood that in other embodiments, this is not limiting. In the following examples, the instruments, reagents and materials involved, unless otherwise specified, are conventional instruments, reagents and materials already known in the art and are commercially available. The experimental methods, detection methods, and the like in the examples described below are conventional experimental methods and detection methods known in the prior art unless otherwise specified.

Wherein the lipase is derived from Lipozyme Calb of Candida antarctica. And Lipozyme 435, lipozyme TL 100L and Lipozyme TL IM from Thermomyces lanuginosus, lipozyme RM IM from Rhizomucor miehei, NS40086 and eversa transform 2.0FG from Aspergillus oryzae.

Example 1

A process for the preparation of diglycerides comprising the steps of:

weighing the following components in percentage by mass: 0.6 of soybean oil and purified water are heated to 40 ℃ under the stirring speed of 500rpm, lipase (Lipozyme Calb and Lipozyme TL 100L with the mass ratio of 1:1) accounting for 2 percent of the mass of the soybean oil is added after the temperature reaches 40 ℃ for carrying out a first reaction, the reaction is carried out for 48 hours, a first reaction product is prepared, the first reaction product is filtered, the filtrate is collected, the filtrate is centrifuged for 10 minutes under the rotating speed of 4000rpm, and the first upper light phase is collected for standby.

And testing the fatty acid content of the first upper light phase, weighing glycerol and adding the glycerol into the first upper light phase after obtaining the fatty acid content, wherein the mole ratio of the fatty acid to the glycerol is 1:0.75, heated to 60℃at a stirring rate of 500 rpm. After the temperature reached 60 ℃, 1% of lipase (Lipozyme TL IM) by mass of the first upper light phase was added, and reacted at an absolute pressure of 1.5KPa for 12 hours to prepare a second reaction product, the second reaction product was filtered, after collecting the filtrate, the filtrate was centrifuged at a rotation speed of 4000rpm for 10 minutes, and the second upper light phase was collected to obtain a crude diglyceride product.

The crude diglyceride product is separated by multi-stage double-temperature deodorization treatment. First, the crude diglyceride product is subjected to a first deodorization treatment, wherein the conditions of the first deodorization treatment include: the pressure is 0.07Pa, the temperature is 170 ℃, the first deodorization treatment is finished, the heavy phase trapped substance is collected, the heavy phase trapped substance is subjected to the second deodorization treatment, and the conditions of the second deodorization treatment comprise: the pressure was 200Pa and the temperature was 310 ℃. The ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is equal to 2, the feed flow rate of the first deodorization treatment being twice the feed flow rate of the second deodorization treatment. And after the second deodorization treatment is finished, collecting a light phase trapped substance, heating the light phase trapped substance to 105 ℃, adding magnesium silicate accounting for 5% of the mass of the light phase trapped substance as an adsorbent under the condition of the vacuum degree of-92 Kpa, and removing residual byproducts by adsorption for 20 min.

Example 2

A process for the preparation of diglycerides comprising the steps of:

weighing the following components in percentage by mass: 1.2 heating soybean oil and purified water to 85 ℃ under the stirring speed of 250rpm, adding lipase (Lipozyme 435) accounting for 10% of the mass of the soybean oil after the temperature reaches 85 ℃, carrying out a first reaction for 12 hours to prepare a first reaction product, filtering the first reaction product, collecting filtrate, centrifuging the filtrate for 10 minutes under the rotating speed of 4000rpm, and collecting a first upper light phase for later use.

And testing the fatty acid content of the first upper light phase, weighing glycerol and adding the glycerol into the first upper light phase after obtaining the fatty acid content, wherein the mole ratio of the fatty acid to the glycerol is 1:0.8, heated to 40℃with a stirring rate of 250 rpm. After the temperature reaches 40 ℃, adding lipase (Lipozyme RM IM) accounting for 10% of the mass of the first upper light phase, reacting for 2 hours under the absolute pressure of 0.05KPa to prepare a second reaction product, filtering the second reaction product, collecting filtrate, centrifuging the filtrate for 10 minutes at the rotating speed of 4000rpm, and collecting the second upper light phase to obtain a crude diglyceride product.

The crude diglyceride product is separated by multi-stage double-temperature deodorization treatment. First, the crude diglyceride product is subjected to a first deodorization treatment, wherein the conditions of the first deodorization treatment include: the pressure is 200Pa, the temperature is 240 ℃, the first deodorization treatment is finished, the heavy phase trapped substance is collected, the second deodorization treatment is carried out on the heavy phase trapped substance, and the conditions of the second deodorization treatment comprise: the pressure was 0.07Pa and the temperature was 250 ℃. The ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is equal to 2, the feed flow rate of the first deodorization treatment being twice the feed flow rate of the second deodorization treatment. And after the second deodorization treatment is finished, collecting a light phase trapped substance, heating the light phase trapped substance to 120 ℃, adding neutral clay which is 1 percent of the mass of the light phase trapped substance as an adsorbent under the condition of the vacuum degree of-85 Kpa, and removing residual byproducts by adsorption for 30 minutes.

Example 3

A process for the preparation of diglycerides comprising the steps of:

weighing the following components in percentage by mass: 1.0, heating soybean oil and purified water to 55 ℃ at a stirring rate of 400rpm, adding lipase (Lipozyme 435) accounting for 5% of the mass of the soybean oil after the temperature reaches 55 ℃, carrying out a first reaction for 24 hours to prepare a first reaction product, filtering the first reaction product, collecting filtrate, centrifuging the filtrate at a rotating speed of 4000rpm for 10 minutes, and collecting a first upper light phase for later use.

And testing the fatty acid content of the first upper light phase, weighing glycerol and adding the glycerol into the first upper light phase after obtaining the fatty acid content, wherein the mole ratio of the fatty acid to the glycerol is 1:0.5, heated to 50℃with a stirring rate of 400 rpm. After the temperature reached 50 ℃, 3% of the mass of the first upper light phase lipase (Lipozyme 435) was added, and reacted at an absolute pressure of 1.1KPa for 2 hours to prepare a second reaction product, the second reaction product was filtered, after collecting the filtrate, the filtrate was centrifuged at 4000rpm for 10 minutes, and the second upper light phase was collected to obtain a crude diglyceride product.

The crude diglyceride product is separated by multi-stage double-temperature deodorization treatment. First, the crude diglyceride product is subjected to a first deodorization treatment, wherein the conditions of the first deodorization treatment include: the pressure is 0.5Pa, the temperature is 205 ℃, the first deodorization treatment is finished, the heavy phase trapped substance is collected, the heavy phase trapped substance is subjected to the second deodorization treatment, and the conditions of the second deodorization treatment comprise: the pressure was 0.5Pa and the temperature was 300 ℃. The ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is equal to 2, the feed flow rate of the first deodorization treatment being twice the feed flow rate of the second deodorization treatment. And after the second deodorization treatment is finished, collecting a light phase trapped substance, heating the light phase trapped substance to 110 ℃, adding silicon dioxide accounting for 2% of the mass of the light phase trapped substance as an adsorbent under the condition of the vacuum degree of-90 Kpa, and removing residual byproducts by adsorption for 28 min.

Example 4

A process for the preparation of diglycerides comprising the steps of:

weighing the following components in percentage by mass: heating soybean oil and purified water of 0.6 to 60 ℃ at a stirring rate of 325rpm, adding lipase (Eversa Transform 2.0 FG) accounting for 5% of the mass of the soybean oil after the temperature reaches 60 ℃, performing a first reaction for 22 hours to obtain a first reaction product, filtering the first reaction product, collecting filtrate, centrifuging the filtrate at a rotating speed of 4000rpm for 10 minutes, and collecting a first upper light phase for later use.

And testing the fatty acid content of the first upper light phase, weighing glycerol and adding the glycerol into the first upper light phase after obtaining the fatty acid content, wherein the mole ratio of the fatty acid to the glycerol is 1:0.5, heated to 45℃with a stirring rate of 325 rpm. After the temperature reaches 45 ℃, adding lipase (Lipozyme RM IM) accounting for 5% of the mass of the first upper light phase, reacting for 4 hours under the absolute pressure of 0.8KPa to prepare a second reaction product, filtering the second reaction product, collecting filtrate, centrifuging the filtrate for 10 minutes under the rotating speed of 4000rpm, and collecting the second upper light phase to obtain a crude diglyceride product.

The crude diglyceride product is separated by multi-stage double-temperature deodorization treatment. First, the crude diglyceride product is subjected to a first deodorization treatment, wherein the conditions of the first deodorization treatment include: the pressure is 5Pa, the temperature is 220 ℃, the first deodorization treatment is finished, the heavy phase trapped substance is collected, the second deodorization treatment is carried out on the heavy phase trapped substance, and the conditions of the second deodorization treatment comprise: the pressure was 0.5Pa and the temperature was 270 ℃. The ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is equal to 2, the feed flow rate of the first deodorization treatment being twice the feed flow rate of the second deodorization treatment. And after the second deodorization treatment is finished, collecting a light phase trapped substance, heating the light phase trapped substance to 105 ℃, adding neutral clay and magnesium silicate (weight ratio of 1:2) which are 3 percent of the mass of the light phase trapped substance under the condition of the vacuum degree of-88 Kpa, and carrying out adsorption removal for 25 minutes by taking the neutral clay and the magnesium silicate as adsorbents to remove residual byproducts.

Example 5

A process for the preparation of diglycerides comprising the steps of:

weighing the following components in percentage by mass: heating 0.8 of soybean oil and purified water to 55 ℃ at a stirring speed of 400rpm, adding lipase (NS 40086) accounting for 8% of the mass of the soybean oil after the temperature reaches 55 ℃, carrying out a first reaction for 18 hours to prepare a first reaction product, filtering the first reaction product, collecting filtrate, centrifuging the filtrate at a rotating speed of 4000rpm for 10 minutes, and collecting a first upper light phase for later use.

And testing the fatty acid content of the first upper light phase, weighing glycerol and adding the glycerol into the first upper light phase after obtaining the fatty acid content, wherein the mole ratio of the fatty acid to the glycerol is 1:0.5, heated to 55℃with a stirring rate of 325 rpm. After the temperature reached 55 ℃, 8% of the mass of the first upper light phase lipase (Lipozyme RM IM) was added, and the reaction was carried out for 2 hours under an absolute pressure of 0.4KPa to prepare a second reaction product, the second reaction product was filtered, after the filtrate was collected, the filtrate was centrifuged at 4000rpm for 10 minutes, and the second upper light phase was collected to obtain a crude diglyceride product.

The crude diglyceride product is separated by multi-stage double-temperature deodorization treatment. First, the crude diglyceride product is subjected to a first deodorization treatment, wherein the conditions of the first deodorization treatment include: the pressure is 1Pa, the temperature is 190 ℃, the first deodorization treatment is finished, the heavy phase trapped substance is collected, the second deodorization treatment is carried out on the heavy phase trapped substance, and the conditions of the second deodorization treatment comprise: the pressure was 1Pa and the temperature was 295 ℃. The ratio of the number of stages of the second deodorization treatment to the number of stages of the first deodorization treatment is equal to 2, the feed flow rate of the first deodorization treatment being twice the feed flow rate of the second deodorization treatment. And after the second deodorization treatment is finished, collecting a light phase trapped substance, heating the light phase trapped substance to 120 ℃, adding neutral clay, silicon dioxide and magnesium silicate (the weight ratio is 1:1:2) which are 4% of the mass of the light phase trapped substance into the light phase trapped substance under the condition of the vacuum degree of-85 Kpa, and carrying out adsorption and removal for 22min to remove residual byproducts.

Comparative example 1

Substantially the same as in example 5, except that:

comparative example 1 only the crude diglyceride product was subjected to the first deodorization treatment, and the collected heavy phase retentate was the product, without the second deodorization treatment and the adsorbent adsorption removal treatment. And, the conditions of the first deodorization treatment in comparative example 1 include: the pressure was 1Pa and the temperature 205 ℃.

Comparative example 2

Substantially the same as in example 5, except that:

comparative example 2 only the crude diglyceride product was subjected to the second deodorization treatment, and the collected light phase retentate was the product, without the first deodorization treatment and the adsorbent adsorption removal treatment. And, the conditions of the second deodorization treatment in comparative example 2 include: the pressure was 1Pa and the temperature was 250 ℃.

Comparative example 3

Substantially the same as in example 5, except that: the obtained crude diglyceride product is the final product, and the first deodorization treatment, the second deodorization treatment and the adsorbent adsorption removal treatment are not carried out.

Comparative example 4

Substantially the same as in example 5, except that:

the conditions for the second deodorization treatment of comparative example 4 include: the pressure was 1Pa and the temperature was 180 ℃. Further, comparative example 4 was not subjected to the adsorbent adsorption/removal treatment.

Comparative example 5

Provided is a fat composition, wherein the fat is common soybean oil.

The products prepared in examples 1 to 5 and comparative examples 1 to 5 were subjected to oil composition analysis, trichloropropanol ester and glycidyl ester composition analysis. Wherein the grease composition analysis is performed according to GB/T26623-2011. Trichloropropanol ester and glycidyl ester composition analysis was performed according to SN/T5220-2019. The analysis results are shown in Table 1 below.

TABLE 1 analysis results of grease composition, trichloropropanol ester and glycidyl ester composition

* ND: undetected (.ltoreq.100. Mu.g/kg)

As can be seen from Table 1, the purity of diglycerides in the products prepared in examples 1 to 5 was 99.5% or more, and the content of trichloropropanol ester and glycidyl ester was extremely low.

As can be seen from comparison of comparative examples 1 to 4 with example 5, if the crude diglyceride product was not subjected to the deodorization treatment, either the first deodorization treatment or the second deodorization treatment was performed only on the crude diglyceride product, or the second deodorization treatment was performed at a temperature lower than the first deodorization treatment, it was not possible to obtain high-purity diglycerides.

From the analysis result of comparative example 5, it was found that the main component of ordinary soybean oil was triglyceride and did not contain diglyceride.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims

1. A process for the preparation of diglycerides, comprising the steps of:

subjecting the heavy phase retentate to a second deodorization treatment, and collecting a light phase retentate; the method comprises the steps of,

2. The method for producing diglycerides according to claim 1, wherein the temperature of the first deodorization treatment is 170 ℃ to 240 ℃ and the temperature of the second deodorization treatment is 270 ℃ to 310 ℃;

alternatively, the pressure of the first deodorization treatment is 0.07Pa to 200Pa, and the pressure of the second deodorization treatment is 0.07Pa to 200Pa.

3. The method for producing diglycerides according to claim 1, wherein the ratio of the number of steps of the second deodorizing treatment to the number of steps of the first deodorizing treatment is 2 or more.

4. The process for producing diglycerides according to claim 1, wherein the feed flow rate of the first deodorization treatment is twice or more the feed flow rate of the second deodorization treatment.

5. The method for producing diglycerides according to any one of claims 1 to 4, wherein the step of adding an adsorbent to the light phase retentate to adsorb residual byproducts satisfies at least one of the following conditions:

(1) The temperature is 105-120 ℃;

(2) The vacuum degree is-92 KPa to-85 KPa;

(4) The treatment time is 20 min-30 min; the method comprises the steps of,

6. The method for producing a diglyceride according to any one of claims 1 to 4, wherein the lipase comprises a first lipase and a second lipase, and the step of producing a crude diglyceride comprises:

separating the first reaction product and collecting a first upper light phase;

7. The method for producing diglycerides according to claim 6, wherein the first reaction satisfies at least one of the following conditions:

(1) The mass ratio of the vegetable oil to the water is 1 (0.6-1.2);

(3) The stirring speed of the first reaction is 250 rpm-500 rpm;

(5) The reaction time of the first reaction is 12-48 h.

8. The method for producing diglycerides according to claim 6, wherein the second reaction satisfies at least one of the following conditions:

(1) The molar ratio of the glycerin to the fatty acid contained in the first upper light phase is (0.5-0.8): 1;

(3) The stirring speed of the second reaction is 250 rpm-500 rpm;

(4) The reaction temperature of the second reaction is 40-60 ℃;

(6) The reaction pressure of the second reaction is 0.05 KPa-1.5 KPa.

9. The method of producing diglycerides according to claim 6, wherein the means for separating the first reaction product comprises: and filtering the first reaction product, collecting filtrate, and centrifuging the filtrate.

10. The method of producing diglycerides according to claim 6, wherein the means for separating the second reaction product comprises: and filtering the second reaction product, collecting filtrate, and centrifuging the filtrate.