Figure Page 2.1 Generic structure of a flavonoid molecule (Balasundram et al., 2006). 9 2.2 Generic structure of the major classes of flavonoids. 9 2.3 Generic structure of condensed and hydrolysable tannins. 11 2.4 Theoretical extraction curve. Part I is linear. Parts II and III are nonlinear. 15 2.5 Diagram of a SFE process (adapted from Rosa et al., 2009). 18 2.6 Formation of carbonic and alkyl carbonic acids. 20 3.1 Elder shrub, cluster of elderberries, and detail of elderberries. 26
3.2 Fresh and dried elderflowers. 27
3.3 Portuguese Douro-Sul region, where elder is mainly found (ARS-Norte, 2008).
27 3.4 Chemical structures of anthocyanins and flavonol in elderberries. 30 3.5 Chemical structures of phenolic acids and flavonoids in elderflowers. 31 3.6 Natural distribution area of P. pinaster (Alía and Martín, 2003). 35 3.7 Maritime pine trees and detail of pine needles, cones and bark. 36 3.8 Tara pods, whole seeds and de-coated seeds (endosperm halves). 44 3.9 Major tara tannins and respective chemical structures (Clifford et al., 2007). 46 4.1 Main flavonoids present in elderberries: cyanidin 3-glucoside (R - glucose)
and cyanidin 3-sambubioside (R - xylose-glucose); quercetin 3-rutinoside (R- rutinose).
62
4.2 Schematic diagram of the employed high pressure extraction apparatus. 65 4.3 Kinetics of the 1st step (SFE) elderberry pomace extraction. 68 4.4 Obtained global yields (d.b.) for elderberry pomace extractions. 69 4.5 Analysis of low polarity compounds by anisaldehyde sprayed TLC. 73 4.6 Analysis of high polarity compounds by NP sprayed TLC plates, observed at
365 nm.
74 4.7 HPLC profile of in natura elderberry pomace extract obtained by PSE using
EtOH (90%) + CO2 (10%), at 313 K and ~20 MPa recorded at 520 nm.
75 5.1 Total anthocyanin contents determined by HPLC (TA) versus total monomeric
anthocyanin contents determined by the pH differential method (TMA) of elderberry pomace extracts, obtained by fractionated PSE with diverse CO2/EtOH/H2O solvent mixtures.
95
Figure Page 5.2 Total monomeric anthocyanin contents (TMA) and polymeric color (PC) of
elderberry pomace extracts, obtained by fractionated PSE with diverse CO2/EtOH/H2O solvent mixtures.
96
6.1 Schematic diagram of the employed supercritical extraction equipment. 107 6.2 Total extraction yields of supercritical CO2 extractions of dry elderflowers. 109 6.3 Analysis of volatile compounds and phenolic compounds in elderflower
extracts, by anisaldehyde-sulfuric acid solution and NP/PEG solution sprayed TLC plates.
110
6.4 Gas chromatograph of elderflowers extracts obtained by SFE (318 K, 600 kg/m3), hydrodistillation and volatile compounds collected during conventional ethanol extraction.
111
6.5 Oxidation inhibitions (after 3 h of reaction) of supercritical CO2 extracts of elderflowers.
112 7.1 Pinus radiata extract fractions and commercial tannin-rich products considered
in this study.
123 7.2 P. pinaster bark extraction yields (%, d.b.) obtained by two-hour long aqueous
extractions at the solvent boiling point, using a 1:10 solid-to-solvent ratio.
129 7.3 CIE a* and b* coordinates of P. pinaster bark extracts obtained by two-hour
long aqueous extractions at the solvent boiling point. 137 8.1 Schematic diagram of the employed SFE apparatus. 148
8.2 Pine bark FSFE kinetics results. 153
8.3 Mass ratio of solute in the solvent phase (Y90 min and YCER) for 1st step and 2nd step FSFE.
155 8.4 TLC analysis of pine bark FSFE extracts obtained at 303 K. Results were
drawn using ACD/TLC Plate Tool for ChemSketch, Freeware version 10.02.
157 8.5 GC chromatograms obtained for pine bark extract samples. 161 8.6 Zoomed GC chromatogram obtained for pine bark extract sample obtained by
1st step CO2-FSFE, at 303 K and 10 MPa.
162 8.7 Characterization of pine bark 2nd step FSFE CO2+EtOH (10%, v/v) extracts by
HPLC.
163 8.8 Catechin + epicatechin concentration (µg/mg, d.b.) as a function of CO2 density
for pine bark 2nd step FSFE CO2:EtOH (90:10, v/v) extracts. 164 8.9 Isobaric oxidation inhibition profiles (obtained after 3 hours inhibition assays)
for pine bark extracts. 1ststep FSFE CO2 and 2nd step FSFE CO2:EtOH (90:10, v/v).
165
8.10 Isobaric oxidation inhibition (%) for pine bark 2nd step FSFE CO2:EtOH (90:10, v/v) extracts, as a function of catechin + epicatechin contents.
166 9.1 Overall curves of P. pinaster bark HPE at 323 K, ~20 MPa, with 12.5×10-5 kg/s
of scCO2 and placing comminuted raw material directly in the extraction cell or in a cylindrical 120-mesh screen.
182
Figure Page 9.2 Overall curves of P. pinaster bark PSE using three different flow rates (low,
medium and high). 183
9.3 Overall extraction curves of HPE of P. pinaster bark at 303 K and ~25 MPa, at a solvent flow rate of ~7.5×10-5 kg/s and diverse EtOH volumetric percentages in the solvent mixture.
184
9.4 Analysis of low polarity compounds by anisaldehyde sprayed TLC plates of first and second steps fractionated high pressure extracts acquired at different flow rates, hydrodistillation and Soxhlet extracts, and second step fractionated and non-fractionated high pressure extracts acquired with CO2:EtOH (90:10) at different flow rates.
188
9.5 GC chromatograms of P. pinaster bark fractionated first step CO2 extracts obtained at 323 K, 20.5 MPa and 6.9×10-5 kg/s. 193 9.6 Total phenolic compounds and condensed tannins of P. pinaster bark
non-fractionated high pressure extracts obtained using CO2:EtOH solvent mixtures with 10, 30, 50 and 70% of EtOH, at 303 K, 25 MPa and 7.6×10-5 kg/s.
196
9.7 Reversed-phase HPLC traces of P. pinaster bark F-HPE and NF-HPE extracts obtained using CO2:EtOH (90:10) solvent mixtures at different flow rates. 197 9.8 Reversed-phase HPLC traces of P. pinaster bark NF-HPE extracts obtained
using CO2:EtOH solvent mixtures with 10, 30, 50 and 70% of EtOH (at 303 K, 25 MPa and 7.6×10-5 kg/s) and of Soxhlet ethanolic extract.
198
10.1 Representation of the assayed solvent mixtures with diverse CO2-EtOH-H2O
molar fractions. 213
10.2 Overall curve of supercritical CO2 extraction from tara seed coat at 313 K and
20 MPa. 215
10.3 Overall curves of PSE from tara seed coat at 313 K, 20 MPa and diverse CO2, EtOH and H2O molar fractions in the solvent mixture.
216 10.4 Representation of the solvent mixture group of points that led to similar MCER
and YCER values.
218 10.5 Response surface contour plot curve for the extraction yield, extracts´ total
phenolic compounds and extracts´ IC50 values of tara seed coat high pressure extracts.
222
10.6 Lipoxygenase IC50 values versus phenolic compounds contents of tara seed coat extracts obtained by PSE at 313 K and 20 MPa with diverse CO2/EtOH/H2O solvent mixtures.
223
10.7 Oxidation inhibition of tara seed coat extracts obtained by PSE at 313 K, 20 MPa and diverse CO2, EtOH and H2O molar fractions. 224
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