229
like” theory, thus helping the choice of the adequate deep eutectic solvent regarding
its polarity. Due to the high number of starting components, different combinations
can lead to various deep eutectic solvent with different properties. Recently, deep
eutectic solvents have been tailored to be target-specific via the selection of specific
individual components based on the analytes via in silico methods (Fernández et al.
2018). Unique interactions between the deep eutectic solvents with target analytes
make it possible to selectively separate trace of this analyte from complex matrices
(Fernández et al. 2018).
6.3.7 pH
Since this parameter determines the state of the analytes, the pH of deep eutectic
solvent can affect the structures of the bioactive compounds subjected to extraction
and thus the extraction efficiency. In their neutral forms, analytes are generally
much easier to be extracted by weakly polar solvents. However, in their ionic forms,
they have fewer tendencies to be extracted. Therefore, the pH of the extraction procedure should be higher than or near to the pKa values of the studied analytes
(Mohebbi et al. 2018). The pH of different deep eutectic solvent changes differently
with temperature, and the acidity of deep eutectic solvent is highly affected by the
type of hydrogen bond donor (Tang et al. 2014). The highly polar molecules demand
an acidic environment for a better extraction; therefore, organic acid-based deep
eutectic solvents or natural deep eutectic solvents are the best choice. This was
observed by organic acid-based natural deep eutectic solvent that showed the best
extraction results for anthocyanin (polar compounds), while sugar-based natural
deep eutectic solvents were a better choice for other phenolic compounds (Radošević
et al. 2016). Finally, due to their amphoteric properties, the extraction of proteins is
highly influenced by the pH (Li et al. 2016). The isoelectric point of the protein
should be taken into consideration (Li et al. 2016). pH contributes as well for the
reduction of the matrix interference (Karimi et al. 2017).
6.3.8 Cell Disruption Ability
Cell disruption plays an important role in the extraction of analytes; therefore, it is
considered as a revealed parameter for the extraction efficiency. There is no doubt
that some extraction techniques cause cell disruption such as ultrasonication, microwave extraction, as well as hot reflux extraction and others. However, the solvent
used have an additional impact on the cell disruption. Using different extraction
techniques followed by scanning electron microscope analysis, it was proved that
deep eutectic solvents cause cell rupture more efficiently than water or other conventional extraction solvents (Table 6.11). This leads to the full release of the target
analyte and its subsequent dissolution in deep eutectic solvent.
6 Methods for Extraction of Bioactive Compounds from Plant and Animal Matter…
like” theory, thus helping the choice of the adequate deep eutectic solvent regarding
its polarity. Due to the high number of starting components, different combinations
can lead to various deep eutectic solvent with different properties. Recently, deep
eutectic solvents have been tailored to be target-specific via the selection of specific
individual components based on the analytes via in silico methods (Fernández et al.
2018). Unique interactions between the deep eutectic solvents with target analytes
make it possible to selectively separate trace of this analyte from complex matrices
(Fernández et al. 2018).
6.3.7 pH
Since this parameter determines the state of the analytes, the pH of deep eutectic
solvent can affect the structures of the bioactive compounds subjected to extraction
and thus the extraction efficiency. In their neutral forms, analytes are generally
much easier to be extracted by weakly polar solvents. However, in their ionic forms,
they have fewer tendencies to be extracted. Therefore, the pH of the extraction procedure should be higher than or near to the pKa values of the studied analytes
(Mohebbi et al. 2018). The pH of different deep eutectic solvent changes differently
with temperature, and the acidity of deep eutectic solvent is highly affected by the
type of hydrogen bond donor (Tang et al. 2014). The highly polar molecules demand
an acidic environment for a better extraction; therefore, organic acid-based deep
eutectic solvents or natural deep eutectic solvents are the best choice. This was
observed by organic acid-based natural deep eutectic solvent that showed the best
extraction results for anthocyanin (polar compounds), while sugar-based natural
deep eutectic solvents were a better choice for other phenolic compounds (Radošević
et al. 2016). Finally, due to their amphoteric properties, the extraction of proteins is
highly influenced by the pH (Li et al. 2016). The isoelectric point of the protein
should be taken into consideration (Li et al. 2016). pH contributes as well for the
reduction of the matrix interference (Karimi et al. 2017).
6.3.8 Cell Disruption Ability
Cell disruption plays an important role in the extraction of analytes; therefore, it is
considered as a revealed parameter for the extraction efficiency. There is no doubt
that some extraction techniques cause cell disruption such as ultrasonication, microwave extraction, as well as hot reflux extraction and others. However, the solvent
used have an additional impact on the cell disruption. Using different extraction
techniques followed by scanning electron microscope analysis, it was proved that
deep eutectic solvents cause cell rupture more efficiently than water or other conventional extraction solvents (Table 6.11). This leads to the full release of the target
analyte and its subsequent dissolution in deep eutectic solvent.
6 Methods for Extraction of Bioactive Compounds from Plant and Animal Matter…