EP3283605A2

EP3283605A2 - Process and installation for extraction of biological active compounds from plants and continuous reactor for ultrasound and microwave assisted extraction of biological active compounds from plants

Info

Publication number: EP3283605A2
Application number: EP16740464.9A
Authority: EP
Inventors: Mariana PATRASCU; Sylviu Amundala Renaud KUMBAKISAKA
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-01-19
Filing date: 2016-01-18
Publication date: 2018-02-21
Also published as: WO2016118034A2; WO2016118034A3; RO130896A0; EP3283605A4

Abstract

This invention refers to a process for extraction of active biological compounds from plants by simultaneous application of ultrasounds and microwaves in a laminar continuous flow regime of extraction, under conditions of a controlled flow regime, at temperatures which do not affect the structure of thermolabile active biological compounds and to a new type of chemical reactor for extraction of active biological compounds from plants, continuous, for carrying out this process. Also, the invention refers to an installation for continuous extraction of active biological compounds with the new type of chemical reactor for extraction. By the application of the process according to the invention there are obtained essential oils, fatty oils, blends of polyphenols, blends of anthocyanins, terpenes, sesquiterpenes compounds, stabilized proteins or in pure form which cannot be obtained by others techniques of extraction due to thermal degradation and/or structural degradation occurring during the process of extraction.

Description

Process and installation for extraction of biological active compounds from plants and continuous reactor for ultrasound and microwave assisted

extraction of biological active compounds from plants

Technical field

The present invention refers to a process for extraction of active biological compounds from plants by simultaneous application of ultrasounds and microwaves and a new type, continuous, chemical reactor for extraction of active biological compounds from plants provided with means for simultaneous application of ultrasounds and microwaves.

Also, invention refers to an installation for continuous extraction of active biological compounds from plants with the new type of chemical reactor for extraction.

Background art

There are known from literature many methods for extractions of essential oils from biological materials, through a variety of mechanisms and equipment configurations. Thus, the patent applications EP 1439218 A1, EP 1618798 A1, EP 1629725 B1, US 5002784 describe extraction processes of volatile oils from different types of plant materials and microwaves assisted devices for the related processes as described. Patent application EP 1439218 A1 describes an extraction process of natural volatile substances from biological materials by hydrodistillation by means of microwaves, without addition of solvent. Also, the patent application EP 1439218 A1 refers to a microwave extraction apparatus of volatile compounds from biological material by a hydrodistillation process, which comprises a microwave oven, with a microwave chamber for receiving the biological material and a condensation chamber wherein, the condensation chamber is situated above the microwave chamber and is connected to the microwave chamber through a channel bundle. This system improves the condensation and cooling area of the water vapours from outside of the microwave chamber. On the other hand, this extraction process takes place with relatively low yields and the extraction apparatus has a functioning in batch system, applicable for small quantities of biological material.

Another extraction method of the volatile oils from biological material consists of microwave application to biological material under low pressure conditions until the natural substances are released from the biological material and followed by their condensation, as described in patent application EP 1618798 A1. Further, the application EP 1618798 A1 describes an apparatus with the following components: a microwave cavity with a receiving region of the microwaves, allowing a low pressure in microwave area and a condensation chamber, which are connected by a tube. Another extraction method of the volatile substances which have a low solubility in water, from biological material is described in the patent EP 1629725 B1. The extraction method as presented in patent, includes the following steps:

1) Introduction of biological material without solvent in the microwave cavity; 2) Irradiation of the biological material until it is released at least some of the natural substances of interest from the biological material;

3) Transportation of the natural substances by convection from microwave area to the cooling area;

4) Cooling of the natural substances until they are condensed;

5) Transportation of the released natural substances from the condensation area to the collecting area which contains a hydrophobic solvent for dissolution of natural substances.

The water carrying natural substances partially returns in the microwave area by a drainage system.

In secondary step the natural substances or the least soluble in water are separated from the hydrophobic solvent. The water vapours are generated inside the microwave cavity from the mixture water/biological material.

Another patent, US 5002784 describes a new method of selective extraction of natural compounds from raw biological material which requires a short time period for extraction and uses a microwave applicator. This method it is in concordance with all principles of conventional extraction, but in comparison with these ones the extraction yields are much better. The subsequent operations of separation and purification require special conditions.

All these extraction processes proceed at low speed and relative low extraction yields. It also does not allow obtaining polyphenols, anthocyanins and proteins and other thermolabile compounds.

Disclosure of invention The technical problem solved by the present invention is given by the need to get a higher yield of extraction, with high purity of the extraction product, and to obtain also other valuable components such as polyphenols, anthocyanins, proteins, etc, whilst processing a much higher quantity of biological material.

The process of extraction of the active biological compounds from plants according to the invention solves this problem by simultaneous application of ultrasounds and microwaves to the plant material, in a continuous regime of extraction, in a controlled flow regime, at temperatures, at atmospheric pressure or vacuum and, if necessary, under inert gas atmosphere, which do not affect the structure of active biological compounds. Preferably, the controlled flow regime is a laminar regime (Re < 2300). Thus, a first object of the invention is a process for extraction of active biological compounds from plants which comprises the following steps:

- introducing the mixture of plant material and solvent, prepared in advance, in an extraction zone with controlled continuous laminar flow regime, the extraction zone being provided successively with means for the application of ultrasounds and means for the application of microwaves;

- applying simultaneously ultrasounds and microwaves to the mixture of plant material and solvent which goes through the extraction zone;

- volatile active biological compounds released in the extraction zone are collected in the condensing zone;

- cooling the volatile active biological compounds collected in the condensing zone until they condense completely;

- evacuating the mixture of plant material and solvent from extraction zone and separating the liquid extraction mixture containing solvent and non-volatile active biological compounds extracted from the exhausted plant material, which liquid extraction mixture is subjected to further processing appropriate for the separation of non-volatile active biological compounds from the extraction solvent.

In another embodiment of the invention, the mixture of plant material and solvent released from extraction zone is reintroduced in the extraction zone, recirculating so until all active biological compounds are extracted. Then, the liquid extraction mixture is separated from the plant material and is processed for obtaining the active biological compounds. Another object of invention is a continuous reactor for extraction of active biological compounds, in the form of a pipeline, whose length is substantially higher than the diameter thereof and which assures a zone of extraction with a continuous flow regime, controlled, with supplying at one end and evacuation at the other end and which is provided with means for generating and simultaneous application of ultrasounds and microwaves and means for collecting the active biological compounds released in the extraction process.

Also, the reactor is provided with means for controlling and monitoring the temperature and working pressure, and the vacuum, the reflected and incident microwaves power as well as means for carrying out the extraction process under inert atmosphere, whenever this is necessary.

The reactor diameter is between 10mm and 2200 mm, depending of the operating manner, production capacity and the type of plant material which is subjected to the extraction process.

Another object of invention is an installation for extraction of active biological compounds from plants which comprises a continuous extraction reactor according to the present invention, connected to a circuit for the transportation of the mixture of plant material and solvent, which makes the connection from a storage vessel for the said mixture to the supplying end of the extraction reactor, and respectively, from the evacuation end of the extraction reactor, to the collecting vessel for the mixture and a pump for supplying the mixture in the extraction reactor.

The process according to the invention has many advantages: the quantity of biological material processed per charge is at least 100 times higher than in the batch system, the foaming phenomenon of the biological material is avoided and implicitly the undesired events, the extraction yield of natural substances increases by at least minimum 25%, the time of extraction is significantly reduced, it is obtained a product of high purity and high quality in terms of chemical composition compared to other methods and systems for extraction in a field of microwave and/or non- conventional methods, such as: extraction under pulsed electrical field, enzyme- assisted extraction, extraction with liquids under pressure, extraction with supercritical fluids.

The biological material subject to the extraction can be processed at the same time also for other valuable components, such as: polyphenols, anthocyanins, proteins, etc. Also, the process according to the invention presents the advantages:

• Obtaining pure volatile oils;

• Obtaining of polyphenols, anthocyanins and proteins;

• Reduced time of extraction;

· Extraction temperature controlled depending on the extraction product desired to be obtained;

• Low temperature of extraction in order to avoid thermal degradation of thermolabile compounds;

• High volume of extraction;

· High yield of extraction ;

• Possibility of strengthening the electric or magnetic field of the microwave depending on the chemical nature of the «target» active biological compound;

• The extraction assisted by microwaves and ultrasounds is a fast, selective, non-polluting process, which works with a high speed of extraction, easy to control from a technological point of view.

Figure 1 represents schematically an embodiment of an installation of extraction of active biological compounds with the recirculation of the mixture of plant material and solvent to be extracted according to the invention comprising a continuous extraction reactor provided with means of generating and application of ultrasounds and microwaves and a system for collecting and condensing of active biological compounds resulted from the extraction process, connected to a transportation circuit for the plant material to be processed that makes the connection from a vessel for the said mixture to the supplying end of the extraction reactor, and respectively, from the evacuation end of the extraction reactor, back, to the vessel for the mixture and a process pump for supplying and recirculation.

Further it is presented the process according to the invention. It is selected the plant material to be processed for its content of active biological compounds.

The plant material may be in the form of plants, seeds, fruits, flowers, wooden material. The plant material is milled at a grain size which must not be greater than 20 pm or chopped if the plant material subjected to extraction is fresh.

The plant material may be fresh or dried. In a storage vessel, it is prepared a mixture of plant material with solvent and it is homogenized so that the whole quantity of plant material, respectively plant, wood or seeds to be in contact with the solvent.

The mixing ratio, by weight, of plant material and solvent is dependent on the plant material to be extracted, shape, size, condition, and it is between 1 :2 and 1 :20, preferably between 1 : 2 and 1:10. The solvent may be polar or non-polar. Solvents used for extraction are chosen depending on the active biological compound pursued to be extracted.

For example, deionized water is suitable for extraction of essential oils, anthocyanins, tannins, saponins, terpenes, sesquiterpene.

Ethanol is a solvent suitable for extraction, for example, of alkaloids, terpenes, tannins, polyphenols, flavonoids.

Soybean oil, olive oil, coconut oil are suitable for extraction of fatty oils, terpene compounds, stabilized proteins. The mixture of plant material and solvent is supplied to a continuous extraction reactor by means of a process pump.

The reactor is provided with means for the application of ultrasounds, in the form of a sonotrod (US) and means for the application of microwaves, in the form of a multi- mode or mono-mode microwave cavity (MW).

Also, the reactor is provided with means for controlling and monitoring temperature and the working pressure, and vacuum, reflected and incident microwave power as well as means for ensuring carrying out the extraction process in an inert atmosphere, whenever this is necessary.

The reactor is connected to a drive system with steam of Clevenger type or Florentine flask for the collection and separation of volatile oil.

The ultrasounds and microwaves sources are turned on. The operational parameters are adjusted: time, temperature, vacuum level (where applicable), optionally, inert atmosphere, power of the ultrasounds, the incident power of microwaves, pump flow rate.

The work flow rate is correlated with the power of microwaves and ultrasounds applied to the mixture of plant material and solvent, namely: the greater flow rate it is the higher power of microwaves and ultrasounds are.

When the situation so requires, this proportion may be modified depending on the physical-chemical characteristics of the plant and/or the solvent and the rheqjogical characteristics of the mixture of plant material and solvent. The mixture of plant material and solvent is subjected to simultaneous irradiation of ultrasounds and microwaves.

Power of ultrasounds sources is comprised between 100-1000 W/l and power of microwaves sources is comprised between 100-6000 W/l at a microwave frequency of 2450 MHz or GHz 914.

In an embodiment of the process, the mixture of plant material and solvent is simultaneously irradiated with ultrasounds and microwaves, ultrasonic power ranging between 100-500 W/l and microwave powers between 200- 000 W/l and a frequency of 2450 MHz, at an extraction temperature in the range of 40 to 110 °C, at normal pressure, the extraction time of 10-120 min and a flow rate of the pump of 0.1 to 2 l/min. The extraction of active biological compounds is accomplished under required technological conditions. Depending on the nature of active biological product obtained, namely: essential oil, blend of polyphenols, anthocyanins, or proteins, they are cooled at room temperature, they are conditioned by filtration, drying, centrifugation or lyophilization and they are stored.

By applying the extraction process according to the invention various active biological compounds are obtained comprising for example: essential oils, fatty oils, blends of polyphenols, mixtures of anthocyanins, terpenes, sequiterpenes compounds, stabilized proteins or in pure form.

There are further presented a few non-limiting examples for the application of the present invention.

Example 1

5 Kg dry Rosemary (Rosmarinus Officinalis) (EU origin) are weighed on a technical balance, milled at a graining of about 0.5 mm, introduced in the storage vessel, on which there are added 20 L deionized water, the mass ratio plant/solvent=1 :4.

The mixture is homogenized with a mechanical homogenizer for 30 min., at room temperature, at a speed of 50 rpm.

The pump suction hose is inserted in the storage vessel, the pump is cpupled in order to supply with the continuous reactor, and is turned on at a flow rate of 1 L/min. The ultrasounds sources are turned on at a power of 200 W/L and microwaves at a power of 400 W/L, the Clevenger system of collecting the volatile oil is coupled and the extraction time is set at 90 minutes. After 90 minutes the extraction of the vp!gtile oil has been completed. The volatile oil is separate^ from wafer apd jt is drj£d pn th anhydrous Na2S0₄.The volatile oil thus obtained is stored in dark colour pots, at premises protected from light and heat.

In the collecting vessel of the plant material at the exit from reactor it is obtained an aqueous extract which contains antioxidant compounds. The aqueous extract is separated by filtration from the plant material and it is stored in dark colour pots for subsequent processing. A volatile oil and an aqueous extract are thus obtained. The gas chromatographic analysis of volatile essential oil of Rosemary has shown the main active compounds as presented in Figure 2.

The gas chromatographic analysis of aqueous extract of Rosemary has shown the main active compounds as presented in Figure 3.

The extraction yield was calculated according to the Romanian Pharmacopoeia and British Pharmacopeia at 95%.

Example 2

10 Kg fresh fruits of black currant (Ribes nigrum) are weighed on a technical balance and mixed with 10 L deionized water and 10 L ethylic alcohol 97 degrees of plant origin in the storage vessel. The mixture is homogenized with a mechanical homogenizer for 30 min., at room temperature, at a speed of 100 rpm. The suction pump hose is inserted in the storage vessel and the one for evacuation from reactor in the collecting vessel, the pump is coupled in order to supply with the continuous reactor and is turned on at a flow rate of 0.5 L/min. The ultrasounds sources are turned on at a power of 100 W/L and microwaves at a power of 300 W/L, the extraction time is set at 120 min. After 120 minutes the mixture containing the blend of extracted polyphenols is collected, which is separated by filtration from the plant material. The blend of polyphenols is concentrated by lyophilization. Thus obtained it is stored in dark colour pots at premises protected from light and heat. The extraction yield was calculated according to the Romanian Pharmacopoeia and British Pharmacopeia at 98%. Example 3.

3 Kg walnut kernel (Juglans regia L.) are weighed on a technical balance, milled at a graining of 0.6 mm and mixed with 6 L hexane in storage vessel. The mixture is homogenized with a mechanical homogenizer for 40 min., at room temperature, at a speed of 30 rpm. The suction pump hose is inserted in the storage vessel and the one for evacuation from reactor in the collecting vessel, the pump is coupled to supply with the continuous reactor, and is turned on at a flow rate of 0.2 L/min. The ultrasounds sources are turned on at a power of 300 W/L and microwaves at a power of 600 W/L, the extraction time is set to 60 min. After 60 minutes the mixture thus obtained is collected, which is separated by filtration from the plant material. The mixture of solvent and extracted fatty oil is distilled under vacuum in order to eliminate the solvent, rinsed 3 times with distilled water and dried on anhydrous

The fatty oil thus obtained is stored in dark colour pots, at premises protected from light and heat.

The extraction yield was calculated according to the Romanian Pharmacopoeia and British Pharmacopeia at 94%.

Example 4

5 Kg shell of Palo Santo (Bursela Graveolens) are weighed on a technical balance and mixed with 10 L deionized water in a storage vessel. The mixture is homogenized with a mechanical homogenizer for 30 min., at room temperature, at a speed of 100 rpm. The suction pump hose is inserted in the storage vessel and the one for evacuation from reactor in the collecting vessel, the pump is coupled to supply with the continuous reactor, turned on at a rate of 0.3 L/min. The ultrasounds sources are turned on at a power of 250 W/L and microwaves at a power of 350 W/L, in a monomode system, the Florentine flask is coupled, the extraction time is set at 90 min. After 90 minutes, the volatile essential oil is collected in the Florentine flask, which then is separated from water by a separating funnel and dried on anhydrous Na2S0₄. Thus obtained this is stored in dark colour pots at premises protected from light and heat. There are obtained approximately 500 ml essential oil, with a yield of 98%. The composition of the oil is analysed by gas chromatographic-mass spectrometry method (GC-MS), the results being shown in figure 4. Example 5

5 Kg rose petals (Rosa X Damascena Miller) are weighed and mixed with 12 L deionized water in the storage vessel. The mixture is homogenized with a mechanical homogenizer for 30 min., at room temperature, at a speed of 100 rpm. The suction pump hose is inserted in the storage vessel and the one for evacuation from reactor in the collecting vessel, the pump is coupled in order to supply with the continuous reactor, and it is turned on at a flow rate of 0.3 LJmin. The ultrasounds sources are turned on at a power of 150 W/L and microwaves at a power of 550 W/L, in a multimode system, the Florentine flask is coupled, the extraction time is set at 90 min. After 90 minutes the volatile essential oil is collected in the Florentine flask, which is then separated from water by a separating funnel, at 40-45°C and dried on anhydrous Na2S0 . The volatile essential oil thus obtained is stored in dark colour pots at premises protected from light and heat. There are obtained approximately 5 ml essential oil, with a yield of 95%. The composition of oil is analysed by GC-MS method and physical-chemical characteristics by specific standards, comparative results being presented in the following table:

Claims

1. Process for extraction of active biological compounds from plants characterized in that it comprises the following steps:

- introducing the mixture of plant material and solvent, prepared in advance, in an extraction zone with controlled continuous flow regime, the extraction zone being provided successively with means for the application of ultrasounds and with means for the application of microwaves;

- evacuating the mixture of plant material and solvent from extraction zone and separating the liquid extraction mixture which contains solvent and non-volatile active biological compounds extracted from the exhausted plant material, which liquid extraction mixture is subjected to further processing appropriate for the separation of non-volatile active biological compounds from the extraction solvent.

2. Process according to claim 1 characterized in that the continuous flow regime is a laminar flow regime.

3. Process according to claim 1 characterized in that the application of

ultrasounds to the mixture of plant material and solvent which goes through the continuous extraction zone precedes the application of microwaves.

4. Process according to claim 1 characterized in that there are applied ultrasounds with the power comprised between 100 - 1000 W/l and microwaves with the power comprised between 100 - 6000 W/l and a microwave frequency of 2450 MHz or 914 GHz.

5. Process according to claim 1 characterized in that the powers of ultrasounds and microwaves applied to the mixture of plant material and solvent are determined as depending on the ratio plant material/solvent, the extraction temperature, the extraction time and the flow rate of the supplying pump.

6. Process according to claim 1 characterized in that the active biological compounds collected comprise essential oils, fatty oils, blends of polyphenols, blends of anthocyanins, terpenes, sesquiterpenes compounds, stabilized proteins or in pure form.

7. Reactor for extraction of active biological compounds, continuous, characterized in that it is in the form of a pipeline, whose length is substantially higher than the diameter thereof, which assures a zone of extraction with a laminar continuous flow regime, controlled, with supplying at one end and evacuation at the other end and which is provided with means for generating and simultaneous application of ultrasounds and microwaves and means for collecting the active biological compounds released in the extraction process.

8. The reactor according to claim 7 characterized in that the means for generating and application of ultrasounds are located before the means for generating and application of microwaves and in line with these ones.

9. Installation for continuous extraction of active biological compounds from plants characterized in that it comprises a reactor for extraction according to claim 7, connected to a circuit for the transportation of the mixture of plant material and solvent which makes the connection from a storage vessel for the said mixture to the supplying end of the extraction reactor, and respectively, from the evacuation end of the extraction reactor to a collecting vessel for the mixture and a pump for supplying the mixture in the extraction reactor.