scholarly journals Pressurized Solvent Extraction of Paulownia Bark Phenolics

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 254
Author(s):  
Paula Rodríguez-Seoane ◽  
Beatriz Díaz-Reinoso ◽  
Herminia Domínguez

Paulownia bark is mostly utilized jointly with wood, but the possibility of a separate valorization through the pressurized extraction of bark bioactives has been assessed. Subcritical water extraction and supercritical CO2 extraction are green technologies allowing shorter times than conventional solvent extraction under atmospheric shaken conditions. Subcritical water extraction was carried out at temperatures ranging from 140 to 240 °C and supercritical CO2 extraction was performed at different pressures (10, 20 and 30 MPa), temperatures (35, 45 and 55 °C) and ethanol concentrations (0, 10 and 15% (w/w)). Subcritical water extraction under a non-isothermal operation during heating up to 160 °C (19 min) provided extraction yields up to 30%, and the extracts contained up to 7% total phenolics with an ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radical scavenging capacity equivalent to 35% the activity of Trolox, whereas at 240 °C, the yield decreased to 20%, but the phenolic content reached 21%, and the antiradical activity was equivalent to 85% of Trolox. Supercritical CO2 extraction at 30 MPa, 45 °C and 30 min reached a global yield of 2% after 180 min of extraction, but the product showed very low antiradical capacity. Gallic acid, vanillic acid, vanillin and apigenin were the major phenolic compounds found in the extracts.

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Hongyi Sun ◽  
Xi Yuan ◽  
Zhenya Zhang ◽  
Xin Su ◽  
Min Shi

Subcritical water extraction (SWE) has been employed for the extraction of bioactive compounds from plant materials with cost-effectiveness, less consuming time, and environmental sustainability. To explore the effects of thermal processing during SWE, total organic content (TOC), total sugar, polysaccharides, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (ABTS and DPPH assays) of eight aqueous extracts have been quantitatively investigated. The results indicated that elevated temperatures indeed resulted in significant changes in the constituents and antioxidant activities of okara extracts. Among them, the extract obtained at 220°C exhibited the highest total phenolic, flavonoid content, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging activity, and ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)] radical-scavenging activity. However, phenolic compounds were destroyed after the treatment above 230°C, suggesting that any polymer processing is improper to undertake at higher than this value to achieve the high antioxidant activity. Moreover, a significant positive correlation between TPC or TFC and antioxidant capacity (DPPH and ABTS) values was detected.


2019 ◽  
Vol 26 ◽  
pp. 19-30
Author(s):  
Nur Akmal Ishak ◽  
Muhammad Yusuf Abdul Rashid ◽  
Nur Athirah Zabidi

Banana peels has been shown to possess strong antioxidant which may exhibit protective responses against reactive oxygen species through free radicals scavenging and breaking the autoxidative chain reaction and restore the ‘redox homeostasis’ state. Subcritical water extraction method was used by using water as the solvent and increasing the temperature to between 100 and 374°C and keeping the pressure high enough to maintain the liquid state allowing the dielectric constant (ε) of water becomes like that of an organic solvent, like ethanol or methanol. The extract was collected by using temperatures of 100 °C, 150 °C, 180 °C and 200 °C with 30, 60, 90 and 120 minutes for the investigation of antioxidative compounds and antioxidant activity. The TPC ranged widely from 20.93 to 66.39 mg GAE/g for Pisang Tanduk and 43.64 to 151.40 mg GAE/g for Pisang Cavendish peel extract. While TFC of Pisang Tanduk ranged from 1.94 to 17.19 RE/g and for Pisang Cavendish it was as low from 3.80 to as high as 72.45 RE/g. Radical scavenging activities (inhibition of DPPH) of the extracts ranged from 36.96 to 85.60% for Pisang Tanduk and from 52.26 to 93.68%. Inhibition of ABST scavenging activity showed 97.14 to 99.03% inhibition for Pisang Tanduk. For Pisang Cavendish, it showed from 73.02 to 98.86% inhibition. Although both banana peel extracts appeared to have low TPC and TFC, its antioxidant activities were ranked moderate to high. This implies that antioxidative compounds other than phenolics and flavonoids were probably responsible for inhibition of DPPH.


2009 ◽  
Vol 32 (6) ◽  
pp. 804-816 ◽  
Author(s):  
M. KHAJENOORI ◽  
A. HAGHIGHI ASL ◽  
F. HORMOZI ◽  
M.H. EIKANI ◽  
H. NOORI BIDGOLI

2017 ◽  
Vol 9 (32) ◽  
pp. 4647-4656 ◽  
Author(s):  
Linlin Yan ◽  
Yungang Cao ◽  
Guangyao Zheng

Subcritical water extraction (SWE), a ‘green’ and efficient extraction technology, was applied to extract phenolic antioxidants from pomegranate peel in this study.


Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 398
Author(s):  
Wen-Yue Wang ◽  
Zhao Qin ◽  
Hua-Min Liu ◽  
Xue-De Wang ◽  
Jing-Hao Gao ◽  
...  

Subcritical water treatment has received considerable attention due to its cost effectiveness and environmentally friendly properties. In this investigation, Chinese quince fruits were submitted to subcritical water treatment (130, 150, and 170 °C), and the influence of treatments on the structure of milled wood lignin (MWL) was evaluated. Structural properties of these lignin samples (UL, L130, L150, and L170) were investigated by high-performance anion exchange chromatography (HPAEC), FT-IR, gel permeation chromatography (GPC), TGA, pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), 2D-Heteronculear Single Quantum Coherence (HSQC) -NMR, and 31P-NMR. The carbohydrate analysis showed that xylose in the samples increased significantly with higher temperature, and according to molecular weight and thermal analysis, the MWLs of the pretreated residues have higher thermal stability with increased molecular weight. The spectra of 2D-NMR and 31P-NMR demonstrated that the chemical linkages in the MWLs were mainly β-O-4′ ether bonds, β-5′ and β-β′, and the units were principally G- S- H- type with small amounts of ferulic acids; these results are consistent with the results of Py-GC/MS analysis. It is believed that understanding the structural changes in MWL caused by subcritical water treatment will contribute to understanding the mechanism of subcritical water extraction, which in turn will provide a theoretical basis for developing the technology of subcritical water extraction.


2017 ◽  
Vol 30 (1) ◽  
pp. 579-590 ◽  
Author(s):  
Periaswamy Sivagnanam Saravana ◽  
Adane Tilahun ◽  
Collin Gerenew ◽  
Vo Dinh Tri ◽  
Nan Hee Kim ◽  
...  

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