scholarly journals Pressurized-Liquid Extraction as an Efficient Method for Valorization of Thymus serpyllum Herbal Dust towards Sustainable Production of Antioxidants

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2548
Author(s):  
Živan Mrkonjić ◽  
Dušan Rakić ◽  
Muammer Kaplan ◽  
Nemanja Teslić ◽  
Zoran Zeković ◽  
...  

The aim of this study was to valorize Thymus serpyllum herbal dust, a particular fraction distinguished as an industrial waste from filter-tea production. Pressurized liquid extraction (PLE) was used with the aim of overcoming certain obstacles of conventional extraction techniques in terms of shortening extraction time, reducing solvent consumption and energy costs, using “green” solvents and obtaining high yield and quality products. In order to optimize PLE of T. serpyllum herbal dust, the preliminary screening of the independent variables in order to define the most influential parameters and their domain was done first. After the screening, the optimization study using the face-centered central composite experimental design (CCD) with response surface methodology (RSM) was implemented. Additionally, taking into account the high awareness of the positive influence of antioxidants on the human health and associating it with high content of polyphenolic compounds in various members of Lamiaceae family, PLE has proven to be a great approach for antioxidants recovery from T. serpyllum herbal dust.

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6951
Author(s):  
Norelhouda Abderrezag ◽  
Jose David Sánchez-Martínez ◽  
Ouahida Louaer ◽  
Abdeslam-Hassen Meniai ◽  
Jose A. Mendiola

Ammodaucus leucotrichus is a spontaneous plant endemic of the North African region. An efficient selective pressurized liquid extraction (PLE) method was optimized to concentrate neuroprotective extracts from A. leucotrichus fruits. Green solvents were tested, namely ethanol and water, within a range of temperatures between 40 to 180 °C. Total carbohydrates and total phenolics were measured in extracts, as well as in vitro antioxidant capacity (DPPH radical scavenging), anticholinesterase (AChE) and anti-inflammatory (LOX) activities. Metabolite profiling was carried out by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-q-TOF-MS/MS), identifying 94 compounds. Multivariate analysis was performed to correlate composition with bioactivity. A remarkable effect of the temperature using water was observed: the higher temperature, the higher extraction yield, the higher total phenolic content, as well as the higher total carbohydrates content. The water extract obtained at 180 °C, 10.34 MPa and 10 min showed meaningful anti-inflammatory (IC50LOX = 39.4 µg/mL) and neuroprotective activities (IC50AChE = 55.6 µg/mL). The Principal Components Analysis (PCA) and the cluster analysis correlated these activities with the presence of carbohydrates and phenolic compounds.


2021 ◽  
Vol 13 (22) ◽  
pp. 12578
Author(s):  
Vasileios M. Pappas ◽  
Vassilis Athanasiadis ◽  
Dimitrios Palaiogiannis ◽  
Konstantina Poulianiti ◽  
Eleni Bozinou ◽  
...  

Fοllow up with our previous study on the extraction of saffron processing waste polyphenols using deep eutectic solvents, the objective of this examination was a comparative evaluation of pressurized liquid extraction (PLE), stirred-tank extraction (STE) and stirred-tank extraction with ultrasonication pretreatment (STE/UP) with respect to the recovery of pigments and antioxidant polyphenols from saffron processing waste. Aqueous solutions of citric and lactic acids at two different concentrations were used as green solvents. The extracts obtained under the specified conditions were analyzed for total pigment and total polyphenol yields as well as for their ferric-reducing power and antiradical activity. Furthermore, each produced extract was analyzed with liquid chromatography–mass spectrometry to profile its analytical polyphenolic composition. In all cases, PLE provided inferior results compared to the two other techniques, producing extracts with lower polyphenolic concentration and weaker antioxidant properties. On the other hand, no specific pattern was detected concerning the effect of ultrasonication, acid type and acid concentration. Hierarchical cluster analysis indicated that stirred-tank extraction with 1% (w/v) lactic acid and ultrasonication pretreatment might be the highest-performing combination, providing extracts with increased polyphenol and pigment concentration; however, it also enhanced antioxidant activity. It was also concluded that the significantly shorter extraction time when using PLE might be an important element in further optimizing the process, buttressing the use of this technique for the establishment of innovative and sustainable-by-design extraction methodologies.


Marine Drugs ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 308
Author(s):  
Nerea Muñóz-Almagro ◽  
Bienvenida Gilbert-López ◽  
Pozuelo-Rollón M. Carmen ◽  
Yolanda García-Fernandez ◽  
Carlos Almeida ◽  
...  

In the present study, the chemical composition of the microalga Euglena cantabrica was investigated. The extraction of bioactive compounds was done using pressurized liquid extraction (PLE) at different temperatures (40–180 °C) and using green solvents (ethanol-water mixtures). A statistical design of experiments was used to optimize the maximum antioxidant capacity of the extracts by response surface methodology. The antioxidant capacity was determined through the inhibition of 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, while the chemical analyses of the extracts were carried out using different chromatographic techniques. Chlorophylls and carotenoids were analyzed by high-performance liquid chromatography coupled to a diode array detector and mass spectrometry (HPLC-DAD-MS/MS) and carbohydrates by gas chromatography with flame ionization detection (GC-FID) and high-pressure size-exclusion chromatography coupled to an evaporative light-scattering detector (HPSEC-ELSD). The results showed different possibilities for the extraction conditions, depending on the desired bioactivity or chemical composition. Briefly, (i) mixtures of ethanol-water containing around 40% ethanol at 180 °C gave the best antioxidant capacity, (ii) mixtures containing around 50% ethanol at 110 °C gave the best yield of β-glucan paramylon, and (iii) the use of pure ethanol at a low temperature (40 °C) is the best choice for the recovery of carotenoids such as diatoxanthin. Summing up, E. cantabrica seems to be a good candidate to be used in biorefinery to obtain different bioactive compounds.


Author(s):  
F. Monchoux ◽  
A. Rocher ◽  
J.L. Martin

Interphase sliding is an important phenomenon of high temperature plasticity. In order to study the microstructural changes associated with it, as well as its influence on the strain rate dependence on stress and temperature, plane boundaries were obtained by welding together two polycrystals of Cu-Zn alloys having the face centered cubic and body centered cubic structures respectively following the procedure described in (1). These specimens were then deformed in shear along the interface on a creep machine (2) at the same temperature as that of the diffusion treatment so as to avoid any precipitation. The present paper reports observations by conventional and high voltage electron microscopy of the microstructure of both phases, in the vicinity of the phase boundary, after different creep tests corresponding to various deformation conditions.Foils were cut by spark machining out of the bulk samples, 0.2 mm thick. They were then electropolished down to 0.1 mm, after which a hole with thin edges was made in an area including the boundary


Author(s):  
Lucía Castro-Vázquez ◽  
Virginia Rodríguez-Robledo ◽  
María Plaza-Oliver ◽  
Manuel J. Santander-Ortega ◽  
M. Victoria Lozano ◽  
...  

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 866
Author(s):  
Erik E. Allcca-Alca ◽  
Nilton C. León-Calvo ◽  
Olivia M. Luque-Vilca ◽  
Maximiliano Martínez-Cifuentes ◽  
José Ricardo Pérez-Correa ◽  
...  

The pisco industry in Peru generates large amounts of grape pomace, which is a natural source of bioactive compounds with potential nutraceutical applications. Hot pressurized liquid extraction (HPLE) with water-ethanol solvent mixtures (20–60%) at high temperatures (100–160 °C) was applied to recover polyphenols from the skin and seeds of a Peruvian pisco-industry grape-pomace waste. At the same HPLE conditions (60% ethanol, 160 °C), the seed fraction extracts contained ~6 times more total polyphenol and presented ~5 times more antioxidant activity than the extract from the skin fraction. The lowest ethanol concentration (20%) and the highest temperature (160 °C) achieved the highest recovery of flavanols with 163.61 µg/g dw from seeds and 10.37 µg/g dw from skins. The recovery of phenolic acids was maximized at the highest ethanol concentration and temperature with 45.34 µg/g dw from seeds and 6.93 µg/g dw from skins. Flavonols were only recovered from the skin, maximized (17.53 µg/g dw) at 20% of ethanol and the highest temperature. The recovery of specific polyphenols is maximized at specific extraction conditions. These conditions are the same for seed and skin extractions. This alternative method can be used in other agroindustrial wastes in order to recover bioactive compounds with potential applications in the pharmaceutical and food industry.


Sign in / Sign up

Export Citation Format

Share Document