scholarly journals Isolation of gallic acid, caffeine and flavonols from black tea by on-line coupling of pressurized liquid extraction with an adsorbent for the production of functional bakery products

LWT ◽  
2020 ◽  
Vol 117 ◽  
pp. 108661 ◽  
Author(s):  
Mariana C. Souza ◽  
Mariana P. Santos ◽  
Beatriz R. Sumere ◽  
Laise C. Silva ◽  
Diogo T. Cunha ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Black Tea ◽  
Liquid Extraction ◽  
Pressurized Liquid Extraction ◽  
Bakery Products ◽  
On Line ◽  
Line Coupling

scholarly journals Glycerol as Alternative Co-Solvent for Water Extraction of Polyphenols from Carménère Pomace: Hot Pressurized Liquid Extraction and Computational Chemistry Calculations

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 474 ◽  
Author(s):  
Nils Leander Huamán-Castilla ◽  
María Salomé Mariotti-Celis ◽  
Maximiliano Martínez-Cifuentes ◽  
José Ricardo Pérez-Correa
Keyword(s):  
Hydrogen Bond ◽  
Computational Chemistry ◽  
Gallic Acid ◽  
Liquid Extraction ◽  
Grape Pomace ◽  
Water Extraction ◽  
Pressurized Liquid Extraction ◽  
Hydroxyl Group ◽  
Solvent Mixtures ◽  
Structure Property

Glycerol is a co-solvent for water extraction that has been shown to be highly effective for obtaining polyphenol extracts under atmospheric conditions. However, its efficacy under subcritical conditions has not yet been studied. We assessed different water-glycerol mixtures (15%, 32.5%, and 50%) in a hot pressurized liquid extraction system (HPLE: 10 MPa) at 90 °C, 120 °C, and 150 °C to obtain extracts of low molecular weight polyphenols from Carménère grape pomace. Under the same extraction conditions, glycerol as a co-solvent achieved significantly higher yields in polyphenols than ethanol. Optimal extraction conditions were 150 °C, with 32.5% glycerol for flavonols and 50% for flavanols, stilbenes, and phenolic acids. Considering gallic acid as a model molecule, computational chemistry calculations were applied to explain some unusual extraction outcomes. Furthermore, glycerol, methanol, ethanol, and ethylene glycol were studied to establish an incipient structure–property relationship. The high extraction yields of gallic acid obtained with water and glycerol solvent mixtures can be explained not only by the additional hydrogen bonds between glycerol and gallic acid as compared with the other alcohols, but also because the third hydroxyl group allows the formation of a three-centered hydrogen bond, which intensifies the strongest glycerol and gallic acid hydrogen bond. The above occurs both in neutral and deprotonated gallic acid. Consequently, glycerol confers to the extraction solvent a higher solvation energy of polyphenols than ethanol.

Off-line coupling of pressurized liquid extraction and LC/ED for the determination of retinyl acetate and tocopherols in infant formulas

Talanta ◽  
2006 ◽  
Vol 70 (5) ◽  
pp. 1094-1099 ◽  
Author(s):  
M.M. Delgado-Zamarreño ◽  
M. Bustamante-Rangel ◽  
M. García-Jiménez ◽  
A. Sánchez-Pérez ◽  
R. Carabias-Martínez
Keyword(s):  
Liquid Extraction ◽  
Pressurized Liquid Extraction ◽  
Infant Formulas ◽  
Retinyl Acetate ◽  
Line Coupling

scholarly journals Characteristics of a novel on-line micro pressurized liquid extraction method

2020 ◽  
Vol 98 (10) ◽  
pp. 623-629 ◽  
Author(s):  
Bradley M. Taylor ◽  
Kevin B. Thurbide
Keyword(s):  
Rapid Heating ◽  
Liquid Extraction ◽  
Pressurized Liquid Extraction ◽  
Thermal Mass ◽  
Fast Analysis ◽  
Pharmaceutical Tablets ◽  
Typical Time ◽  
Dynamic Extraction ◽  
On Line ◽  
Better Than

A novel on-line micro pressurized liquid extraction (μPLE) method is introduced, which directly interfaces miniaturized solid sample preparation with HPLC for fast analysis. The technique employs rapid heating to remove analytes from 5–10 mg samples in typically 20–40 s using only about 300 μL of solvent. The resulting extract is then internally transferred to an HPLC injector for chromatographic analysis. Results show that good analyte recoveries can be achieved, similar to conventional PLE and off-line μPLE approaches, without manual sample handling. For example, 103% ± 3% (n = 4) of the acetylsalicylic acid present in pharmaceutical tablets was extracted into methanol after 20 s at 180 °C. Further, 105% ± 9% (n = 4) of the caffeine present in a green tea sample was extracted into methanol after 40 s at 275 °C. Typical time to analysis was about 95 s total for most samples, and solvents could also be easily alternated during trials to increase extract selectivity. The on-line μPLE system was applied to the extraction of model PAHs from a biochar matrix and was found to extract 97% ± 5% (n = 4) of anthracene present in the sample after a 30 s static and 60 s dynamic extraction at 220 °C. This yield is much better than results obtained by previous approaches and is attributed to the small size, high temperature, low thermal mass, and dynamic flow of the system. Findings indicate that the on-line μPLE system can greatly assist in such extractions and provide a useful method for rapidly preparing solid samples for analysis using little solvent.

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