*8.2.7 Turbo-distillation extraction or turbo-extraction (turbolysis)*

Turbo-distillation was patented in 1983 by Martel, and has been used in several companies as an industrial purpose for extracting EOs from hard matrixes (such as wood, bark, and seeds) [83]. The extraction process is similar to hydrodistillation with slight modifications [84]. The turbo-extraction or turbolysis is based on extraction with stirring and simultaneous reduction of particle size. Due to of high shearing force, cells disruption leads to rapid dissolution of the active constituents. It results in an extraction time of the order of minutes and the plant content is almost completely depleted [85]. Compare to hydrodistillation, turbo-distillation minimize extraction time and energy consumption and prevents the degradation of volatile constituents (**Figure 9**) [84].

In 2017, Martins and collaborators studied the turbo-extraction of stevioside and rebaudosideo A from *Stevia rebaudiana* dried and powdered leaves. The extraction is carried out by applying a fractional factorial design that allowed the evaluation of the main effects of drug powder size, solvent to drug ratio by weight, temperature, stirring and time on the yield of these glycosides. Their work demonstrated that turbo-extraction was promising for *Stevia rebaudiana* glycosides extraction.

*Extraction of Bioactive Compounds from Medicinal Plants and Herbs DOI: http://dx.doi.org/10.5772/intechopen.98602*

#### **Figure 9.**

*Laboratory turbo-Clevenger: (a) schematic, (b) bench apparatus. The vessel (1); the rotor (2); the turbo shredder (3); the thermometer (4); the distillation column (5); the condenser (6); the receiver-cum separator (7) [46, 84].*

It stimulated new research on the purification of these extracts, which became an exciting source of income for developing countries such as India and Brazil [86]. Perino and collaborators showed that the essential oil extracted by turbodistillation in 30 minutes were quantitatively (yield and kinetics profile) and qualitatively (aromatic profile) similar to those obtained using conventional hydrodistillation in 3 hours. They concluded that this process, which gave a reduced extraction time, was perfectly adapted to the extraction of hard matrixes [84]. It can be advantageous over dynamic maceration.

#### *8.2.8 Counter-current extraction (CCE)*

In this procedure, the wet raw material is pulverized to produce a fine slurry. The target material is moved in one direction (usually as a fine slurry) within a cylindrical extractor where it comes in contact with extracting solvent. Further, the starting material moves making more concentrated extract. Thus, complete extraction is possible when the amounts of material and the flow rate of solvent are optimized the complete extraction is possible. The process is extremely efficient, takes little time and poses no danger when high temperature is applied. Lastly, the extracts come out sufficiently concentrated at one end of the extractor, while the residue falls on the other end [50]. This extraction procedure has great advantages:


#### *8.2.9 Solid-phase extraction (SPE)*

Solid-phase extraction (SPE) is a sample preparation technology using chromatographic packing material, solid particle, commonly found in a cartridge-type device, to chemically separate the different components. Samples are almost constantly in the liquid state (although special applications can be run with some samples in the gas phase). In this method, the dissolved or suspended compounds in a liquid mixture are separated from other compounds depending on their physical and chemical properties. The technically correct name for this technology is "Liquid–Solid Phase Extraction", since the chromatographic particles are solid and the sample is in the liquid state [87].

SPE has many benefits, but four significant benefits deserve special attention:

i. simplification of complex sample matrix along with compound purification;

ii. reduce ion suppression or enhancement in MS applications;

iii. capability to fractionate sample matrix to analyze compounds by class;

iv.trace concentration (enrichment) of very low-level compounds.

This rapid, economical and sensitive technique uses different types of cartridges and disks, with various sorbents, where the solute molecules are preferentially attached over the stationary phase.

#### *8.2.10 High-voltage-assisted extraction*

The principle of this equipment is similar to PEF, with the difference that electrical discharge is made through a small point. For this, a needle electrode is used from which the release is made in a plate ground electrode.

These methods are known as greener methods, are often better than conventional ones in terms of high yields, high selectivity, lower solvent consumption and shorter extraction time. They are also found to be environmentally ecofriendly since energy, and organic solvent consumption are reduced. The combination of extraction methods to obtain high purity extracts or high overall yields are described in the literature [40, 88–90]. Its main advantage is the operability in continuous mode, which is very important from an industrial and economic point of view [80].

#### *8.2.11 Phytonics process*

A new solvent-based on hydrofluorocarbon-134a and a new technology to optimize its remarkable properties in the extraction of plant material offer significant environmental advantages and health and safety benefits over traditional processes to produce advanced quality natural fragrant oil, flavors and biological extracts.

The technology known as "phytonics process" was developed and patented by Advanced Phytonics Limited (Manchester, UK). Fragrant components of EOs and biological or phytopharmacological extracts that can be used straightly without additional chemical or physical treatment are the products frequently extracted by this process. The properties of the new generation of fluorocarbon solvents have been applied to the extraction of plant material. The core of the solvent is 1,1,2,2-tetrafluoroethane, better known as hydrofluorocarbon-134a (HFC-134a) with a boiling point of – 25°C; a vapor pressure of 5.6 bar at ambient temperature. It

#### *Extraction of Bioactive Compounds from Medicinal Plants and Herbs DOI: http://dx.doi.org/10.5772/intechopen.98602*

is flammable and non-toxic. This product was developed as a replacement for chlorofluorocarbons and more importantly, it does not deplete the ozone layer. By most standards this is a poor solvent that is unable to break up (dissolve) plant waste.

The process is advantageous because the solvents can be customized: by using modified solvents with HFC-134a, the process can be made highly selective in extracting a specific class of phytoconstituents. Likewise, to withdraw a broader spectrum of constituents other modified solvents can be employed. The biological products obtained by this process contain extremely low residual solvent. Residuals are constantly below the levels of detection and are fewer than 20 parts per billion. Therefore, selected solvents have minimal potential reaction effects on the botanical material, and are neither acidic nor alkaline. At the end of each production cycle, the processing plant is sealed so that solvents are constantly recycled and totally recovered. Electricity is the unique utility required to perform these systems and, even then, they consume little energy. There is no scope for the escape of the solvents, and even if some solvents come to escape, they pose no threat to the ozone layer because they do not contain chlorine. The waste product (biomass) from these plants is dry and "ecofriendly" to handle.

As the benefits of this procedure, we have the following:

	- ix.the solvents are entirely recycled within the system.

In biotechnology, the utilization of the phytonics process is frequently employed to extract (e.g., for the production of antibiotics), herbal drug, food, EOs and flavor industries, and pharmacologically active products. It is particularly used to produce top-quality pharmaceutical-grade extracts, pharmacologically active intermediates, antibiotic extracts, and phytopharmaceuticals. However, the fact that it is used in all these areas prevents its use in other areas. The technique is being used to extract highquality essential oils, oleoresins, natural food colors, flavors and aromatic oils from all types of plant material. The technique is also used in refining crude products obtained from other extraction processes. It provides extraction without wax or other contaminants. It helps in the removal of many biocides from contaminated biomass [50].
