8639 research outputs found
Sort by
Fermentation of Common Nettle Extracts by Ligilactobacillus salivarius: New Avenue for the Development of Added-Value Bioactive Products
No full textThe medicinal plants industry generates approximately 30 million tons of by-products annually, most of which remain underutilized. The common nettle (Urtica dioica L., Urticaceae) is a valuable medicinal plant, rich in polyphenols, vitamins, and essential fatty acids, widely used in food and pharmaceutical applications. Its by-products still lack sustainable valorization strategies. This study aimed to valorize nettle tea by-products and flowers using green extraction techniques and microbial biotransformation. Lyophilized aqueous/ethanolic extracts were fermented with Ligilactobacillus salivarius ATCC 11741 to assess whether fermentation could enhance the content and bioavailability of phenolic compounds while maintaining probiotic viability. The results showed that fermentation significantly increased phenolic content and antioxidant activity, with chlorogenic acid concentrations increasing up to 4-fold and caffeic acid derivatives up to 2.5-fold. L. salivarius remained viable during fermentation, demonstrating the potential for the production of added-value extracts and probiotic biomass. These findings indicate that nettle by-products can be efficiently converted into functional ingredients through low-energy, environmentally friendly processes, supporting sustainable production and waste valorization
Ergosterol-Enriched Liposomes with Post-Processing Modifications for Serpylli Herba Polyphenol Delivery: Physicochemical, Stability and Antioxidant Assessment
No full textIn the present study, ergosterol, a novel natural and animal-free alternative sterol, was investigated, and its effects on liposomal properties were assessed. Importantly, ergosterol’s fungal origin offers a sustainable substitute for cholesterol, aligning with current trends in natural and vegan-friendly formulations. Methods: This study explored the effect of ergosterol content (10 mol% vs. 20 mol%) on the encapsulation efficiency (EE), physical properties, morphology, antioxidant activity, lipid peroxidation, and storage stability of Serpylli herba extract-loaded liposomes. Results: Liposomes with 20 mol% ergosterol exhibited significantly higher EE (~81.0%) than those with 10 mol% (~75.6%), along with improved resistance to UV- and freeze-drying-induced reduction in EE. Extract loading resulted in a reduced particle size, indicating favorable bilayer interactions, whereas lyophilization increased size and polydispersity, reflecting structural destabilization. However, 20 mol% ergosterol improved vesicle uniformity and surface charge stability, suggesting enhanced bilayer rigidity. Zeta potential and mobility trends supported improved colloidal stability in ergosterol-enriched systems under all tested conditions. Over 28 days at 4 °C, non-treated extract-loaded liposomes with a higher ergosterol content demonstrated enhanced vesicle integrity. During storage, UV-treated and lyophilized liposomes with 20 mol% ergosterol maintained more consistent size and charge profiles, indicating better membrane reorganization and stability. Nanoparticle tracking analysis demonstrated that ergosterol content modulates vesicle concentration in a dose-dependent manner, highlighting the role of membrane composition in liposome formation and potential dose uniformity. Transmission electron microscopy analysis of extract-loaded liposomes demonstrated well-defined vesicles with intact structural features. A study in a Franz diffusion cell revealed that ergosterol-enriched liposomes significantly delayed polyphenol release compared to free extract, confirming their potential for controlled delivery. Antioxidant activity was preserved in all liposomal systems, with higher ergosterol content supporting improved ABTS radical scavenging potential after stress treatments. FRAP assay results remained stable across formulations, with no major differences between sterol levels. TBARS analysis demonstrated that Serpylli herba extract significantly reduced UV-induced lipid peroxidation in ergosterol-enriched liposomes, underscoring its protective antioxidant role. Conclusions: Higher ergosterol content enhanced liposomal performance in terms of encapsulation, structural resilience, and antioxidant retention, particularly under UV and lyophilization stress. Ergosterol-containing liposomes exhibited improved stability, favorable particle size distribution, and high encapsulation efficiency, while maintaining the antioxidant functionality of the incorporated Serpylli herba polyphenol-rich extract. These findings highlight the potential of ergosterol-based liposomes as robust carriers for bioactive compounds in pharmaceutical and nutraceutical applications that align with current trends in green and vegan-friendly formulations
Maple syrup with prebiotics
No full textЈаворов сируп са пребиотицима представља иновативни производ смањене
калоријске, а веће функционалне
вредности у којем су шећери преведени у биоактивне компоненте фруктоолигосахариде. Овај производ унапређених карактеристика
доприноси побољшању здравља свих потрошача, али и квалитету живота оних
особа које се суочавају са гојазношћу или дијабетесом.Maple syrup with prebiotics is an innovative product with reduced caloric and enhanced
functional value in which sugars have been converted into bioactive components, fructooligosaccharides. This product, with improved characteristics, contributes to the health
of all consumers and enhances the quality of life for individuals managing obesity or
diabetes
The Influence of TiO2 Nanoparticles on Thermal Decomposition of Polyurethane Soft Segments
No full textTesting the behavior of polymeric materials during heating, especially when it comes to materials
that have wide practical application and therefore large commercial importance, such as
polyurethanes, is essential. Results obtained by investigating thermal stability and thermal
decomposition of polymers, including kinetic modeling, can help to understand the mechanism of
thermal degradation reaction and also can be very helpful in an attempt to predict and roughly
evaluate lifetime of polymeric materials. In relation to that, the aim of this work was to examine
the effect of unmodified and surface modified TiO2 nanoparticles on thermal degradation and
thermal degradation kinetics of the soft segments of polyurethane network based on
polycaprolactone and aliphatic hyperbranched polyester. Surface modification of TiO2
nanoparticles was performed using gallic acid ester having C12 long alkyl chain (lauryl gallate).
Results obtained by thermogravimetric analysis performed at different heating rates in nitrogen
atmosphere for pure polyurethane and composites prepared by incorporation of 1.0 wt.% of
unmodified or surface modified TiO2 nanoparticles into polyurethane matrix were compared. It
was established that thermal decomposition of soft segments, i.e. polycaprolactone, is shifted to
higher temperatures for composites, and this shift is more pronounced for the sample prepared
with modified TiO2 nanoparticles. Furthermore, using values of the activation energy of thermal
degradation calculated by model-free Ozawa-Flyyn-Wall method, together with Coats-Redfern
model-fitting method and numerous kinetic models, the degradation mechanism of soft segments
was investigated. It has been shown that the best fitting kinetic model which can be applied to
describe thermal degradation mechanism of the soft polycaprolactone segments in the prepared
samples is the second (for pure polyurethane), i.e. the third (for composites) reaction order
kinetic model
Procena ekološke svesti stanovnika Republike Srbije u kontekstu primene ISO 14001 standarda
No full textProblemi koji se odnose na stanje i unapređenje kvaliteta
životne sredine nisu ograničeni na odgovarajuće geografsko
područje i region, a ovo pitanje aktuelno je kako u zemljama
u razvoju tako i u visoko razvijenim zemljama [1]. U poslednjih
10 godina pitanje zaštite životne sredine postalo je jedno od
vodećih pitanja javnog mnjenja [2]. Osnovni problemi koji se
javljaju u ovom domenu su prekomerna proizvodnja i neadekvatno
skladištenje otpada, ispuštanje zagađujućih materija u medijume
životne sredine: vodu, vazduh i zemljište, globalno zagrevanje
i prekomerna emisija gasova sa efektom staklene bašte. Iz svega
navedenog proizlazi da se na rešavanju ovih problema mora raditi
na globalnom nivou „zajedničkim snagama“ svih društvenopolitičkih aktera. U pronalaženju održivih rešenja moraju se
uključiti svi činioci jednog društva, inženjer, političari, ekonomisti,
menadžeri, sociolozi, prosvetni radnici ali i svaki pojedinac,
na osnovnu sopstvene savesti i savesti [1]. Predviđa se da će u
narednom periodu, daljim tehničko-tehnološkim razvojem doći do
pogoršanja trenutne situacije, što neminovno vodi i do ugrožavanja
zdravlja ljudi
Kinetics studies of metal-complex dye adsorption on waste textile based adsorbent
No full textThis article represents a kinetic study of a metal-complex textile dye adsorption onto an adsorbent prepared from waste cotton textiles collected from a textile-fabrication facility. The qualitative and quantitative characterizations of the obtained adsorbent show that it is a relatively porous and inhomogeneous material. During adsorption, longer contact time causes a greater amount of dye on the adsorbent, i.e. with the duration of the adsorption process the concentration of dye in solution decreases. The kinetic parameters, rate constants, equilibrium adsorption capacities as well as the error statistical parameters, were calculated and discussed. It has been shown that the kinetic adsorption of a metal-complex dye onto the obtained adsorbent can be described best by the Hyperbolic tangent equation. The prepared adsorbent is relatively inexpensive, the raw material is easily available, therefore it could be an alternative for expensive adsorbents used for decolorization in the wastewater treatment processes
Hydrogen evolution on Ir nanoparticles supported by glassy carbon and graphene nanoplatelets
No full textThis study reports on the electrocatalytic activity of Ir nanoparticles (NPs) supported by glassy carbon (GC) and graphene nanoplatelets (GNPs) for the hydrogen evolution reaction (HER) in an acid solution. Ir/GC and Ir/GNPs catalysts were obtained by the electrochemical deposition of Ir on the two supports under the same conditions. SEM imaging revealed small, barely visible, Ir NPs highly dispersed on GC and located mainly on the edges of graphene plates on GNPs support. According to XPS analysis, the amount of the deposited Ir was 1.3 at% (15.9 wt%) in Ir/GC and 1.4 at% (16.5 wt%) in Ir/GNPs. Ir/GNPs catalyst has shown a higher HER activity, and potential for 10 mA/cm2 of −0.064 V, compared to −0.073 V for Ir/GC. The 32 mV/dec Tafel slope for Ir/GC and 38 mV/dec for Ir/GNPs indicate the Volmer-Tafel and Volmer-Heyrovski reaction pathways, respectively
Assessing the Emissions and Suitability of Agro-Based Pellets for Small-Scale Residential Heating Appliances in Serbia
No full textEmissions from small-scale heating appliances significantly contribute to exacerbating Serbia’s severe air quality challenges. This study investigates two types of pellets, produced from wheat crop residue and a mixture of wheat and rapeseed, as potential alternatives to wood pellets. The analysis covers key solid biofuel characteristics, including heating value, moisture, volatile matter, elemental composition, ash content, and melting temperature, in accordance with normative specifications. Results reveal that agropellets from wheat and the mixture fail to meet established requirements, disqualifying them from any ENplus classification. Emission characteristic tests, conducted in an automatic residential pellet stove, measure O2, CO2, CO, NOx, SO2, and TOC. Comparative analysis with wood pellets quantitatively indicates higher gaseous pollutant emissions from agropellets. Notably, the combustion of agropellets proves unsuccessful, leading to the extinguishing of the fire in the appliance, rendering them unsuitable for household use. The findings underscore the importance of ensuring high-quality pellets are available on the market and in domestic appliances, presenting implications for end-users and policymakers. Addressing these issues is crucial for mitigating air quality concerns and further study associated with heating in households
The Organic-Functionalized Silica Nanoparticles as Lipase Carriers for Biocatalytic Application: Future Perspective in Biodegradation
No full textOver the past three decades, organic reactions catalyzed by lipase have been extensively studied. To overcome the drawbacks of free enzymes and develop new and sustainable biocatalysts, various insoluble forms of lipases were examined. Especially interesting are lipases immobilized on silica nanoparticles (SiNPs) due to their promising unique and advantageous physicochemical properties. Therefore, the present paper presents an overview of different organic functionalization methods of SiNP surfaces to create a more favorable microenvironment for lipase molecules. Given the high commercial value of lipases in biotechnological applications, the second part of this paper highlights the key industrial sectors utilizing these nanobiocatalysts. This review discusses the key industrial applications of silica-based lipase nanobiocatalysts, including biodiesel production, flavor ester synthesis, and pharmaceutical applications such as racemization. Special attention is given to emerging technologies, particularly the use of immobilized lipases in polymer biodegradation and polymerization reactions. These advances have paved the way for innovative solutions, such as self-degrading bioplastics, which hold significant promise for sustainable materials and environmental protection. This comprehensive overview underscores the transformative potential of lipase–SiNP nanobiocatalysts in both industrial and environmental contexts
Rare Earth Element Adsorption from Water Using Alkali-Activated Waste Fly Ash
No full textAs new technologies are developed, the demand for rare earth elements (REEs)
has increased, despite limited awareness of their significant impact on people and the
environment. In this study, waste fly ash was used as a precursor to synthesize inorganic
aluminosilicate polymers by adding an activator to the alumina and silica compounds of
the ash. Due to their structure and adsorption potential, their application for the removal
of selected REEs (Gd3+, Y3+, and Sc3+) from water has been investigated. A decrease in the
intensity of the quartz peak at 2θ of 26.6◦ in the XRD spectrum and the disappearance of
the albite and mullite peaks due to dissolution during alkaline activation in both modified
samples were observed. The appearance of a peaks at 2θ of 29.3◦ and 39.3◦ corresponding
to calcite in the modified sample indicates the presence of wood ash. A shifting of the band
in the DRIFT spectrum to 1030 cm−1 on the spectra of modified samples corresponds to
the vibrations of Al-O and Si-O bonds and the formation of a polymeric network structure
(Si-O-Si or Si-O-Al). According to pHPZC values, thermodynamic and kinetic parameters,
and chemical composition, the presumed mechanism of REE adsorption is chemisorption
and ion exchange. The highest adsorption efficiencies (up to 95%) for all examined REEs in
both single and mixed REE solutions were obtained from an alkali-activated mixture of fly
ash and wood ash. The results of this research are significant for expanding knowledge
about the removal of REEs from the environment, the reduction of waste ash by their
modification, and their potential subsequent use in construction as additives