Concentration of tea extracts by osmotic evaporation: optimisation of process parameters and effect on antioxidant activity

In this work, the concentration process of three different tea extracts (medicinal Rosil No. 6, Black, and Forest Fruit teas) using the osmotic evaporation (OE) process, was studied. The effect of the OE process on the content of phenolic compounds and antioxidant activity was evaluated. The concentration process was carried out in a hollow-fibre membrane contactor with an effective surface area of 0.54 m2. The tea extract was circulated through the shell side of the contactor, while a concentrated osmotic solution (CaCl2 5 M) was circulated inside the fibres. The flux, the driving force, and the mass transfer coefficient were evaluated. A decrease of the water flux over time was observed and was attributed only to the decrease of the driving force, caused by the dilution of the osmotic solution. Using a surface area/feed volume ratio of 774 m2 m3, it is possible to reach a tea concentration of 40% (w/w) in 5 h, with a constant water flux and without losing the phenolic content and antioxidant potential in most teasinfo:eu-repo/semantics/publishedVersio

Hydrogenotrophic activity under increased H₂/CO₂ pressure: effect on methane production and microbial community

H2 and CO2 are main compounds of synthesis gas. Efficient conversion of syngas to biomethane is a straightforward strategy to integrate the energy value of syngas into existing natural gas grid infrastructures. In this study, the effect of initial H2/CO2 (80/20, v/v) pressure on methane production rate and microbial community diversity was assessed in a hyperbaric bioreactor inoculated with anaerobic granular sludge. Several batch experiments were performed to distinguish between the effect of initial total gas pressure and H2/CO2 partial pressure: (1) varying initial gas pressure (from 1 to 6 bar) with 100% H2/CO2 mixture; (2) constant initial gas pressure (5 bar), with increasing H2/CO2 partial pressure (from 1 to 5 bar); (3) varying initial gas pressure (from 2 to 5 bar) with constant H2/CO2 partial pressure (2 bar). In (2) and (3), N2 was used for ensuring the necessary overpressure. Microbial community changes in the system were monitored by 16S rRNA-based techniques (PCR-DGGE). The raise of H2/CO2 initial pressure (100% H2/CO2) from 1 to 5 bar led to an improvement in methane rate production from 0.035 ± 0.014 mmol h1 to 0.072 ± 0.019 mmol h1. Similar methane production rates were observed in reactors operated at the same H2/CO2 partial pressures, even when varying the total initial gas pressure. Hydrogen partial pressure was shown to determine the structure of bacterial communities and diversity decreased with increasing H2/CO2 partial pressure. No significant changes were observed for the archaeal communities

Decolorization of a corn fiber arabinoxylan extract and formulation of biodegradable films for food packaging

UID/AGR/04129/2020Corn fiber from the corn starch industry is a by-product produced in large quantity that is mainly used in animal feed formulations, though it is still rich in valuable components, such as arabinoxylans, with proven film-forming ability. During arabinoxylans’ recovery under alkaline extraction, a dark-colored biopolymer fraction is obtained. In this work, a purified arabinoxylan extract from corn fiber with an intense brownish color was decolorized using hydrogen peroxide as the decolorizing agent. Biodegradable films prepared by casting the decolorized extract exhibited a light-yellow color, considered more appealing, envisaging their application in food packaging. Films were prepared with glycerol as plasticizer and citric acid as cross-linker. Although the cross-linking reaction was not effective, films presented antioxidant activity, a water vapor permeability similar to that of non-decolorized films, and other polysaccharides’ and mechanical properties that enable their application as packaging materials of low-water-content food products.publishersversionpublishe

Recovery and Purification of Cutin from Tomato By-Products for Application in Hydrophobic Films

UID/AGR/04129/2020. Sociedade Ponto Verde—Sociedade Gestora de Resíduos de Embalagens, S.A., through the project entitled “Bioplastics and Edible, Vegan Films”. Publisher Copyright: © 2023 by the authors.Tomato pomace is a low-cost, renewable resource that has been studied for the extraction of the biopolyester cutin, which is mainly composed of long-chain hydroxy fatty acids. These are excellent building blocks to produce new hydrophobic biopolymers. In this work, the monomers of cutin were extracted and isolated from tomato pomace and utilized to produce cutin-based films. Several strategies for the depolymerization and isolation of monomeric cutin were explored. Strategies differed in the state of the raw material at the beginning of the extraction process, the existence of a tomato peel dewaxing step, the type of solvent used, the type of alkaline hydrolysis, and the isolation method of cutin monomers. These strategies enabled the production of extracts enriched in fatty acids (16-hydroxyhexadecanoic, hexadecanedioic, stearic, and linoleic, among others). Cutin and chitosan-based films were successfully cast from cutin extracts and commercial chitosan. Films were characterized regarding their thickness (0.103 ± 0.004 mm and 0.106 ± 0.005 mm), color, surface morphology, water contact angle (93.37 ± 0.31° and 95.15 ± 0.53°), and water vapor permeability ((3.84 ± 0.39) × 10−11 mol·m/m2·s·Pa and (4.91 ± 1.33) × 10−11 mol·m/m2·s·Pa). Cutin and chitosan-based films showed great potential to be used in food packaging and provide an application for tomato processing waste.publishersversionpublishe

Relationships between Membrane Binding, Affinity and Cell Internalization Efficacy of a Cell-Penetrating Peptide: Penetratin as a Case Study

Penetratin is a positively charged cell-penetrating peptide (CPP) that has the ability to bind negatively charged membrane components, such as glycosaminoglycans and anionic lipids. Whether this primary interaction of penetratin with these cell surface components implies that the peptide will be further internalized is not clear.Using mass spectrometry, the amount of internalized and membrane bound penetratin remaining after washings, were quantified in three different cell lines: wild type (WT), glycosaminoglycans- (GAG(neg)) and sialic acid-deficient (SA(neg)) cells. Additionally, the affinity and kinetics of the interaction of penetratin to membrane models composed of pure lipids and membrane fragments from the referred cell lines was investigated, as well as the thermodynamics of such interactions using plasmon resonance and calorimetry.Penetratin internalized with the same efficacy in the three cell lines at 1 µM, but was better internalized at 10 µM in SA(neg)>WT>GAG(neg). The heat released by the interaction of penetratin with these cells followed the ranking order of internalization efficiency. Penetratin had an affinity of 10 nM for WT cells and µM for SA(neg) and GAG(neg) cells and model membrane of phospholipids. The remaining membrane-bound penetratin after cells washings was similar in WT and GAG(neg) cells, which suggested that these binding sites relied on membrane phospholipids. The interaction of penetratin with carbohydrates was more superficial and reversible while it was stronger with phospholipids, likely because the peptide can intercalate between the fatty acid chains.These results show that accumulation and high-affinity binding of penetratin at the cell-surface do not reflect the internalization efficacy of the peptide. Altogether, these data further support translocation (membrane phospholipids interaction) as being the internalization pathway used by penetratin at low micromolecular concentration, while endocytosis is activated at higher concentration and requires accumulation of the peptide on GAG and GAG clustering

Biodegradable Barrier Membranes Based on Nanoclays and Carrageenan/Pectin Blends

The aim of this work is the study of the barrier properties of biodegradable membranes based on commercial pectin and kappa-carrageenan and organically modified nanoclays. Membranes (67% k-carrageenan, 33% pectin) with different amounts of nanoclays (1, 5 and 10%) were prepared by the solution intercalation method and casting. The films exhibited enhanced gas and water vapour barrier properties when compared to the ones without nanoclay particles. A water vapour permeability reduction of 35% for a nanoclay loading of 10 % was observed. The positive impact on the films’ barrier properties of the organic nanoclay particles inclusion, results from a combined effect of increased tortuosity and reduction of water sorption due to the hydrophobic nature of the clay. The permeability to carbon dioxide has been significantly reduced (50% reduction for 1% nanoclay content).Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy analysis indicated the presence of under exfoliated nanoclay aggregates at 10%. The membranes have also shown a decrease of their stiffness and an increase of the elongation at break with the inclusion of nanoclay particles. An attenuation of the membranes transparency was observed, however, the colour measured after the application of test membranes on coloured paper sheets, did not change significantly with the inclusion of nanoclay particles

Poly(ionic liquid)-based engineered mixed matrix membranes for CO2/H2 separation

Unformatted preprintPoly(ionic liquid)s (PIL) have emerged as a class of versatile polyelectrolites, that can be used to prepare new materials able to achieve superior performances compared to conventional polymers. The combination of PILs with ionic liquids (ILs) may serve as a suitable matrix for the preparation of membranes for gas separation. In this work, mixed matrix membranes (MMMs) combining a pyrrolidinium-based PIL, an IL and three highly CO2-selective metal organic frameworks (MOFs) were prepared. The different MOFs (MIL-53, Cu3(BTC)2 and ZIF-8) were used as fillers, aiming to maximize the membranes performance towards the purification of syngas. The influence of different MOFs and loadings (0, 10, 20 and 30 wt.%) on the thermal and mechanical stabilities of the membranes and their performance in terms of CO2 permeability and CO2/H2 ideal selectivity was assessed. The compatibility between the materials was confirmed by SEM-EDS and FTIR spectroscopy. The prepared MMMs revealed to be thermally stable within the temperature range of the syngas stream, with a loss of mechanical stability upon the MOF incorporation. The increasing MOF content in the MMMs, resulted in an improvement of both CO2 permeability and CO2/H2 ideal selectivity. Among the three MOFs studied, membranes based on ZIF-8 showed the highest permeabilities (up to 97.2 barrer), while membranes based on MIL-53 showed the highest improvement in selectivity (up to 13.3). Remarkably, all permeation results surpass the upper bound limit for the CO2/H2 separation, showing the membranes potential for the desired gas separation.This work was partially supported by R&D Units UID/Multi/04551/2013 (Green-it), UID/QUI/00100/2013 (CQE), and the Associated Laboratory Research Unit for Green Chemistry, Technologies and Clean Processes, LAQV which is financed by national funds from FCT/MCTES(UID/QUI/50006/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007265). Ana R. Nabais, Luísa A. Neves and Liliana C. Tomé acknowledge FCT/MCTES for financial support through project PTDC/CTM-POL/2676/2014, FCT Investigator Contract IF/00505/2014 and Post-doctoral research grant SFRH/BDP/101793/2014, respectively. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745734

TOTAL PHENOLIC CONTENT, ANTIOXIDANT AND ANTICANCER ACTIVITIES OF FOUR SPECIES OF SENNA Mill. FROM NORTHEAST BRAZIL

Objective: The present investigation evaluated the antioxidant and anticancer properties and total phenolic contents of four species of Senna: S. gardneri, S. macranthera, S. splendida and S. trachypus from northeast Brazil. Methods: Ethanolic extracts of leaves and roots of the four Senna species were screened for phytochemical procedures. An in-vitro antioxidant study was conducted by means of DPPH and ABTS radical scavenging assays. Anticancer activity was evaluated using the MTT 3-(4,5-dimethylthiazole-2-yl)-2,5- diphenyltetrazolium bromide) method against the HCT-116, SF-295 and OVCAR-8 cancer cell lines. Total phenolic contents were determined using a Folin-Ciocalteau colorimetric assay. Results: Anthraquinones, flavonoids, phenolics, steroids, tannins, triterpenoids, xanthones, and glycosides were detected in all Senna extracts. The results for the antioxidant activity showed that the highest percentage of scavenger radicals was present in the extract from roots of Senna trachypus (StR), which showed higher levels than the two standards used. The highest percentage of inhibition of the cancer cell lines tested was obtained with the leaf extracts of S. gardneri (SgL) and S. splendida (SsL). Conclusion: The ethanolic extracts of the four species of Senna showed antioxidant activity in both assays, and this activity can be attributed to the presence of phenolic compounds such as flavonoids and anthraquinones. S. trachypus showed a higher antioxidant potential than the standards, as well as a higher total phenolic content. Only two of the plants showed promising results for anticancer activity

Lessons on direct seeding to restore Neotropical savanna

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Elucidating how the saprophytic fungus Aspergillus nidulans uses the plant polyester suberin as carbon source

Lipid polymers in plant cell walls, such as cutin and suberin, build recalcitrant hydrophobic protective barriers. Their degradation is of foremost importance for both plant pathogenic and saprophytic fungi. Regardless of numerous reports on fungal degradation of emulsified fatty acids or cutin, and on fungi-plant interactions, the pathways involved in the degradation and utilisation of suberin remain largely overlooked. As a structural component of the plant cell wall, suberin isolation, in general, uses harsh depolymerisation methods that destroy its macromolecular structure. We recently overcame this limitation isolating suberin macromolecules in a near-native state.work partially supported by a grant from Iceland, Liechtenstein and Norway through the EEA financial mechanism (Project PT015), FCT: grant (PEst-OE/EQB/LA0004/2013) and fellowships (SFRH/BD/38378/2007, SFRH/BD/66396/2009, SFRH/BD/66030/2009, SFRH/BD/48286/2008), Fundação Calouste Gulbenkian fellowship (21-95587-B)