CN113462469B

CN113462469B - Low-temperature extraction method of perilla herb oil with linolenic acid content of 70%

Info

Publication number: CN113462469B
Application number: CN202110956027.8A
Authority: CN
Inventors: 孙辉; 张宇; 黄健花; 常明
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-08-19
Filing date: 2021-08-19
Publication date: 2022-08-19
Anticipated expiration: 2041-08-19
Also published as: CN113462469A

Abstract

The invention discloses a low-temperature extraction method of perilla herb oil with 70% of linolenic acid content, which comprises the steps of selecting specific crude perilla herb oil, wherein the mass ratio of phospholipid to wax in the specific crude perilla herb oil is 300-2000: 1, and the content of saturated fatty acid is 5.2-7.8%; and crystallizing the specific crude perilla herb oil at low temperature to obtain the perilla herb oil with high linolenic acid content. The invention fully utilizes the crystallization behavior of perilla oil consisting of different lipid substances, provides a low-temperature preparation process, is beneficial to forming beta type crystals by triglyceride in the perilla oil through regulating and controlling the composition of the perilla oil and the low-temperature crystallization process, solves the problems that the wax crystal form and the triglyceride crystal form are different, the wax crystal form and the triglyceride crystal form are not easy to separate in one step, and the liquid oil yield is too low, and obtains a low-temperature preparation scheme which can remove the wax and the triglyceride with high melting point only by one-step filtration and obtains the perilla seed oil with more than 70 percent of ALA content.

Description

Low-temperature extraction method of perilla herb oil with linolenic acid content of 70%

Technical Field

The invention belongs to the technical field of oil preparation, and particularly relates to a low-temperature extraction method of perilla herb oil with 70% of linolenic acid content.

Background

Alpha-linolenic acid (ALA) is an important human essential fatty acid and is also the most main dietary n-3PUFA source, and has a plurality of physiological functions. The fatty acid of common edible oil is mainly oleic acid and linoleic acid, and the food source for intake of ALA in the diet of residents is limited. In order to meet the nutritional and health requirements of residents in China and prevent ALA deficiency, the development of ALA-rich edible oil products is necessary.

Perilla oil is a typical alpha-linolenic acid (ALA) type oil, and the content of alpha-linolenic acid (ALA) is usually over 50 percent, mostly less than 65 percent, and almost 70 percent. The preparation process of the perilla oil with high ALA content needs to fully consider the characteristics of the oil, namely high unsaturation degree and easy oxidation side reaction, and avoids oil product reduction caused by improper processing.

At present, the method for extracting the alpha-linolenic acid (ALA) with high content is complicated, and the purification yield is too low, so a low-temperature extraction process of the perilla herb oil with simple method and high linolenic acid content is urgently needed in the field.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made keeping in mind the above and/or other problems occurring in the prior art.

Therefore, the invention aims to overcome the defects in the prior art and provide a low-temperature extraction process of perilla oil with high linolenic acid content.

In order to solve the technical problems, the invention provides the following technical scheme: a low-temperature extraction method of perilla herb oil with 70% of linolenic acid content is characterized by comprising the following steps: comprises the steps of (a) preparing a substrate,

selecting specific crude perilla oil, wherein the mass ratio of phospholipid to wax in the specific crude perilla oil is 300-2000: 1, and the content of saturated fatty acid is 5.2-7.8%;

and crystallizing the specific crude perilla herb oil at low temperature to obtain the perilla herb oil with high linolenic acid content.

As a preferred scheme of the low-temperature extraction method of perilla oil with the linolenic acid content of 70 percent, the method comprises the following steps: the low-temperature crystallization comprises a first-stage low-temperature crystallization, a second-stage low-temperature crystallization and a third-stage low-temperature crystallization.

As a preferred scheme of the low-temperature extraction method of perilla oil with the linolenic acid content of 70 percent, the method comprises the following steps: the first stage of low temperature crystallization comprises,

cooling the specific crude perilla herb oil to-10 to-12 ℃ at a cooling speed of 10-14 ℃/h, and rapidly stirring to obtain the perilla herb oil subjected to the first-stage low-temperature crystallization treatment.

As a preferred scheme of the low-temperature extraction method of perilla oil with the linolenic acid content of 70 percent, the method comprises the following steps: the rapid stirring speed is 150-800 rpm, and the stirring time is 2-3 h.

As a preferred scheme of the low-temperature extraction method of perilla oil with the linolenic acid content of 70 percent, the method comprises the following steps: the second stage of low temperature crystallization, comprising,

slowly stirring and cooling the perilla herb oil subjected to the low-temperature crystallization treatment in the first stage to-14 to-18 ℃ at a cooling speed of 2-6 ℃/h, and keeping the temperature for 4h to obtain the perilla herb oil subjected to the low-temperature crystallization treatment in the second stage.

As a preferred scheme of the low-temperature extraction method of perilla oil with the linolenic acid content of 70 percent, the method comprises the following steps: and slowly stirring at the stirring speed of 10-15 rpm.

As a preferred scheme of the low-temperature extraction method of perilla oil with the linolenic acid content of 70 percent, the method comprises the following steps: the third-stage low-temperature crystallization comprises the following steps,

slowly stirring and cooling the perilla herb oil subjected to the low-temperature crystallization treatment in the second stage to-17 to-20 ℃ at a cooling speed of 1-4 ℃/h, keeping the temperature for 10-20 h, and filtering to obtain the perilla herb oil with the high linolenic acid content.

As a preferred scheme of the low-temperature extraction method of perilla oil with the linolenic acid content of 70 percent, the method comprises the following steps: and slowly stirring at a stirring speed of 10-15 rpm.

It is a further object of the present invention to overcome the deficiencies of the prior art and to provide a perilla oil product with a high linolenic acid content, wherein the alpha-linolenic acid content of the product is above 70%.

The invention has the beneficial effects that:

(1) the invention fully utilizes the crystallization behavior of perilla oil consisting of different lipid substances, provides a low-temperature preparation process, is beneficial to forming beta type crystals by triglyceride in the perilla oil through regulating and controlling the composition of the perilla oil and the low-temperature crystallization process, solves the problems that the wax crystal form and the triglyceride crystal form are different, the wax crystal form and the triglyceride crystal form are not easy to separate in one step, and the liquid oil yield is too low, and obtains a low-temperature preparation scheme which can remove the wax and the triglyceride with high melting point only by one-step filtration and obtains the perilla seed oil with more than 70 percent of ALA content.

(2) The invention is beneficial to the triglyceride in the crude perilla herb oil to form beta-type crystals by regulating and controlling the composition of the crude perilla herb oil and the low-temperature crystallization process, realizes the one-step filtration and removal of wax and the triglyceride with high melting point, improves the ALA content of the perilla herb oil, obtains the perilla herb oil with the ALA content of more than 70 percent, has simple and easy method, and is suitable for industrial application.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

The method for calculating the content of the beta-type crystals of the triglyceride in the invention comprises the following steps: XRD analyzes crystal form of the sample, and calculates the percentage content of beta crystal by area normalization method according to diffraction peak of triglyceride.

The method for calculating the ALA content of the filtered perilla herb oil comprises the following steps: after methyl esterification, the perilla herb oil is subjected to GC determination of fatty acid composition, and the ALA percentage content of the perilla herb oil is calculated by adopting an area normalization method.

Example 1

The embodiment provides a low-temperature extraction process of perilla oil with high linolenic acid content, which comprises the following steps:

(1) the phospholipid and wax (mass ratio) of the perilla frutescens crude oil is 1000, then the temperature is reduced to-10 ℃ at the cooling speed of 14 ℃/h, the mixture is rapidly stirred, and then the temperature is slowly stirred at the cooling speed of 4 ℃/h to be reduced to-16 ℃, and the temperature is kept for 4 h;

(2) slowly stirring the crude perilla herb oil treated in the step (1) at a cooling speed of 2 ℃/h, cooling to-18 ℃, keeping the temperature for 15h, and filtering (a filter bag or filter cloth with the aperture of 1 mu m) to obtain liquid oil.

The contents of triglyceride beta-type crystals and ALA in the resulting liquid oil after crystallization of crude perilla oil with different saturated fatty acid contents are shown in Table 1 below.

TABLE 1

As can be seen from Table 1, it is preferable in the present invention that the saturated fatty acid content of the crude oil is between 6.2% and 7.4%, and the ALA content of perilla oil and the ALA increasing amount of perilla oil reach optimum levels. The ALA is improved through crystallization, wherein, in order to realize effective crystallization, a certain amount of saturated fatty acid is necessary, because the saturated fatty acid grease has a higher melting point and is easier to form a solid state, crystal nuclei can be provided for crystallization, and the crystallization process firstly forms the crystal nuclei and then slowly grows; on the other hand, saturated fatty acid can promote the system to form beta type crystal (with large particle and good filtering and separating effect) more easily, and reduce the proportion of beta' type crystal (with small particle and poor filtering and separating effect).

Reasonable saturated fatty acids are preferred in the present invention: not only can ensure a certain amount of beta type crystal proportion, but also can obtain better separation effect; meanwhile, the total amount of crystals cannot be too much due to too high saturated fatty acid, the yield is reduced, ALA is effectively improved, and a certain yield is ensured to be selected to be 6.2-7.4%.

Example 2

This example provides the effect of phospholipid/wax (mass ratio) in crude perilla oil on extraction performance:

the content of saturated fatty acid in the crude perilla oil is 7.0 percent, then the temperature is reduced to-10 ℃ at the cooling speed of 14 ℃/h, and the mixture is rapidly stirred;

then slowly stirring at a cooling speed of 4 ℃/h to cool to-16 ℃, and keeping the temperature for 4 h;

slowly stirring at a cooling speed of 2 ℃/h, cooling to-18 ℃, and keeping the temperature for 15 h;

filtering (filter bag or filter cloth with aperture of 1 μm) to obtain liquid oil.

The contents of triglyceride beta-type crystals and ALA in the resulting liquid oil after crystallization of crude perilla herb oil (mass ratio) with different phospholipids are shown in Table 2 below.

TABLE 2

Phospholipid wax (mass ratio)	300	500	1000	1500	2000
						The ALA content of the filtered perilla oil%	66.8	70.4	71.9	70.8	64.4
Content of triglyceride beta-type crystals%	4.5	23.4	39.5	26.9	18.3
						Yield and%	37	57	61	58	36

As can be seen from Table 2, the preferred mass ratio of phospholipid to wax in the present invention is 500-1000: 1, and the ALA content of perilla oil and the ALA increase amount of perilla oil are at optimal levels.

The phospholipid has amphipathy, the crystallization temperature is between that of the wax and the triglyceride, the wax and the triglyceride are prevented from being completely incompatible due to overlarge crystallization temperature difference, the wax and the triglyceride are better compatible, but when the content of the phospholipid is too high, the wax crystal is completely wrapped, even the system is sticky due to multi-layer wrapping (caused by colloidal characteristics of the phospholipid), and the formation of beta-type crystals with larger particles in the system is not facilitated. Ultimately affecting the separation efficiency. The oil sample with the same triglyceride composition directly influences the proportion of beta type crystals, namely influences the separation effect, by changing the phospholipid and the wax, the mass ratio of the phospholipid to the wax is preferably 500-1000: 1, and the ALA content of the perilla oil and the ALA increment of the perilla oil reach the optimal level;

the crude perilla herb oil obtained by squeezing or leaching naturally contains phospholipid and wax, but the ratio is unreasonable, if the phospholipid is high, part can be removed firstly, namely, a hydration degumming method is usually adopted in the oil processing, namely, a certain amount of water (or phosphoric acid water solution, citric acid water solution and the like) is added to remove part; if the phospholipid is not enough, the phospholipid removed in the earlier processing process can be added, and the wax can also be removed, and the oil removal industry of the wax usually adopts a cooling (the temperature is above zero degree) and centrifugal mode to remove the phospholipid.

Example 3

Influence of whether the first cooling stage is stirred or not in the low-temperature crystallization process:

the content of saturated fatty acid in the perilla frutescens crude oil is 7.0 percent, the mass ratio of phospholipid to wax is 1000, then the temperature is reduced to-10 ℃ at the cooling speed of 14 ℃/h, and the mixture is rapidly stirred;

The results are shown in Table 3.

TABLE 3

First cooling stage	Stirring the mixture	Without stirring
			The ALA content of the perilla herb oil after filtration%	71.9	70.9
Content of triglyceride beta-type crystals%	39.5	11.2

As can be seen from Table 3, it is clear that whether stirring is carried out or not has a great influence on the crystal morphology, and the proportion of the beta form is greatly reduced without stirring, which directly affects the separation effect and the product yield.

Example 4

Influence of the cooling rate in the second cooling stage in the low-temperature crystallization process:

then slowly stirring at different cooling speeds to cool to-16 ℃, and keeping the temperature for 4 hours;

The content of beta-type crystals of triglyceride and ALA content of the obtained liquid oil after crystallization at different cooling rates are shown in Table 4 below.

TABLE 4

The temperature reduction rate of the second temperature reduction stage is DEG C/h	1	2	4	6	8	16
							The ALA content of the filtered perilla oil%	72.1	71.9	71.9	70.8	64.4	61.2
Content of β type crystals of triglycerides%	40.2	39.8	39.5	35.3	20.3	7.2

As can be seen from Table 4, it is clear that the slow cooling rate is beneficial to the formation of beta-type, but the slow cooling rate is low in working efficiency, so that the cooling rate can be controlled to be 2-6 ℃/h in order to ensure the efficiency.

Example 5

Influence of the end temperature of the second cooling stage in the low-temperature crystallization process:

then slowly stirring and cooling to the temperature between minus 12 ℃ and minus 20 ℃ at the cooling speed of 4 ℃/h, and keeping the temperature for 4 h;

slowly stirring at the cooling speed of 2 ℃/h, cooling to-18 ℃, and keeping the temperature for 15 h;

The content of β -type crystals of triglyceride and the ALA content of the resulting liquid oil after crystallization at different temperatures are shown in Table 5 below.

TABLE 5

As can be seen from Table 5, the temperature is too low, which causes most of the oil to crystallize, and the triglyceride with low saturation in the system also crystallizes, while the lower the saturation, the beta-type crystals are more easily formed, so that the beta-type crystal ratio of the system is reduced when the temperature is too low, and the effect of increasing ALA by separation is not good, and the preferable temperature is-14 to-18 ℃.

Example 6

Influence of the cooling rate in the third cooling stage in the low-temperature crystallization process:

slowly stirring at different cooling rates, cooling to-18 deg.C, and keeping the temperature for 15 h;

The content of beta-type crystals of triglyceride and ALA content of the obtained liquid oil after crystallization at different cooling rates are shown in Table 6 below.

TABLE 6

As can be seen from Table 6, the beta type crystal is beneficial to subsequent filtration, the product yield is high, but the working efficiency is low if the cooling speed is too slow, and the cooling speed is preferably controlled to be 1-4 ℃/h.

Example 7

Influence of the end temperature and the constant temperature time of the third cooling stage in the low-temperature crystallization process

The perilla frutescens crude oil is cooled to-10 ℃ at a cooling speed of 14 ℃/h, is rapidly stirred, is slowly stirred at a cooling speed of 4 ℃/h, is cooled to-16 ℃, and is kept at the constant temperature for 4 h;

slowly stirring at a cooling speed of 2 ℃/h, cooling to a certain temperature between minus 17 ℃ and minus 22 ℃, and keeping the temperature for a certain time;

The results are shown in Table 7.

TABLE 7

As can be seen from Table 7, the crystallization temperature is usually low, the constant temperature crystallization time can be shortened, the work efficiency is improved, but the low temperature and the short time are not beneficial to the growth of crystals, the subsequent separation and the product yield are influenced, the crystallization temperature is preferably-17 to-20 ℃, and the constant temperature time is 10 to 20 hours.

Perilla seed oil contains a small amount of wax and is usually subjected to dewaxing treatment. Because the wax and the triglyceride have larger difference of crystal forms, the wax is not beneficial to the triglyceride to grow into coarse beta crystals, and the whole grease after crystallization is in a paste shape and is not easy to be filtered and separated in one step.

The invention also has the function of regulating and controlling crystallization similar to a crystallization promoter by regulating and controlling the ratio of phospholipid and wax, simultaneously realizes dewaxing and high-melting-point fat removal through low-temperature crystallization, and simultaneously realizes winterization and fractionation effects so as to improve the ALA content of the fat. The invention fully researches the crystallization behavior of perilla oil consisting of different lipid substances, provides a low-temperature preparation process, is beneficial to forming beta-type crystals by regulating the composition of perilla crude oil and the low-temperature crystallization process, solves the problems that the triglyceride in the perilla crude oil is not easy to separate in one step and the liquid oil yield is too low due to the difference between the crystal form of wax and the crystal form of triglyceride, and obtains a low-temperature preparation scheme which can remove the wax and the triglyceride with high melting point only by one-step filtration and obtains the perilla seed oil with more than 70 percent of ALA content. According to the invention, through regulating and controlling the composition of the crude perilla herb oil and a low-temperature crystallization process, the beta-type crystal is formed by triglyceride in the crude perilla herb oil, wax and high-melting-point triglyceride are removed through one-step filtration, the ALA content of the perilla herb oil is increased, and perilla herb seed oil with the ALA content of more than 70% is obtained.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

Claims

1. A low-temperature extraction method of perilla oil with high linolenic acid content is characterized by comprising the following steps:

selecting specific crude perilla oil, wherein the mass ratio of phospholipid to wax in the specific crude perilla oil is 1000:1, and the content of saturated fatty acid is 7.0%;

carrying out first-stage low-temperature crystallization, second-stage low-temperature crystallization and third-stage low-temperature crystallization on specific crude perilla oil to obtain perilla oil with high linolenic acid content; wherein the content of the first and second substances,

the first-stage low-temperature crystallization is carried out, the specific crude perilla herb oil is cooled to minus 10 ℃ at the cooling speed of 14 ℃/h and is rapidly stirred, and thus the perilla herb oil after the first-stage low-temperature crystallization treatment is obtained;

the second-stage low-temperature crystallization is to slowly stir the perilla herb oil subjected to the first-stage low-temperature crystallization treatment at a cooling speed of 4 ℃/h to cool to-16 ℃, and keep the temperature for 4h to obtain the perilla herb oil subjected to the second-stage low-temperature crystallization treatment, wherein the stirring speed is 10-15 rpm;

the third stage of low-temperature crystallization is to slowly stir the perilla herb oil subjected to the low-temperature crystallization treatment in the second stage at a cooling speed of 2 ℃/h to cool the perilla herb oil to-18 ℃, keep the temperature for 15h, and filter the perilla herb oil to obtain the perilla herb oil with high linolenic acid content, wherein the stirring speed is 10-15 rpm, and the alpha-linolenic acid content in the perilla herb oil with high linolenic acid content is more than 70%;

after crystallization, the content of triglyceride beta-type crystals in the perilla oil was 39.5%.

2. The low-temperature extraction method of perilla oil with high linolenic acid content as claimed in claim 1, wherein the method comprises the following steps: the rapid stirring speed is 150-800 rpm, and the stirring time is 2-3 h.