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Continuous synthesis of prebiotics in a helical oscillatory baffled reactor
No full textA novel helical oscillatory baffled reactor (HOBR) was utilized for continuous production of prebiotics, using a 3D-printed prototype (4 m in length, 10 mm in diameter). The reactor's performance was evaluated for the synthesis of galactooligosaccharides (GOS) with free enzymes. Continuous operation resulted in high product concentrations, ranging from 100 mmol/l to 200 mmol/l GOS, depending on the experimental conditions. Steady-state concentrations of lactose and GOS were reached after twice the residence time. The potential for recycling was investigated to enhance mixing and prolong retention times, which are beneficial for slow biochemical reactions. However, the results indicated that recycling was unnecessary for a reactor length of 4 m. Additionally, a difference between the input and output mass of the enzyme suggested that a portion of the enzyme was retained within the reactor. Numerical optimization of inlet concentrations and flow rates confirmed that recycling was not required, and that the maximum possible concentration of lactose should be used. The optimal enzyme concentration depends on the objective function, i.e. whether enzyme consumption is considered. The transition from batch to continuous synthesis resulted in enhanced lactose conversion, selectivity, and productivity, highlighting the HOBR as an efficient and effective system for intensifying prebiotic production
Effectiveness of Household Processing Methods in Reducing Pesticide Residues in Apples
No full textDifferent pests and diseases can seriously affect the production and quality of apples. To ensure yield and quality, intensive pesticide application is commonly practiced during apple growth, which frequently results in the presence of pesticide residues in the final product [1]. Therefore, monitoring and reducing pesticide residues in apples is important for protecting consumer’s health. This study was carried out in order to assess the effectiveness of different household processing methods in reducing pesticide residues presence in apple fruits. The methods examined included immersing the apples in tap water, acetic acid and sodium bicarbonate water solutions, and peeling. Apples analyzed in this study were obtained from local markets in Belgrade. The extraction of pesticide residues was performed by applying the QuEChERS method, followed by analysis with liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) [2]. Multiple pesticide residues were detected in the apple samples, indicating widespread application of plant protection products. The results revealed a variable effectiveness of the applied treatments, depending on the chemical properties and surface affinity of each pesticide. Peeling proved to be the most effective method for removing most residues, suggesting that a significant portion of residues is localized on or near the apple skin. However, this method showed limited efficiency for certain systemic pesticides, such as acetamiprid. These findings provide valuable insight for consumers aiming to reduce dietary exposure to pesticide residues through simple domestic practices
Sustainable Valorization of Conifer Cones: A Potent Source of Antioxidants and Bioactive Compounds
No full textIntroduction: Antioxidants are critical in mitigating oxidative stress-related
diseases and play a fundamental role in industrial applications by inhibiting
oxidation, rancidity, and degradation, thereby enhancing product stability
and quality. The identification of waste biomass with potent antioxidant
properties and a high concentration of biologically active compounds is
essential for the sustainable utilization of natural resources. Such biomassderived antioxidants offer a promising, environmentally sustainable
alternative to their synthetic counterparts, contributing to both human health
and industrial sustainability
Evaluation of amino-modified nanocellulose carrier for immobilization of xylanase and application in xylo-oligosaccharide synthesis
No full textIntroduction: Biocatalysis is increasingly recognized as a viable alternative
for synthesizing complex molecules that are significant in industrial
applications. This is achievable through the use of enzymes immobilized on
biopolymers, which serve as environmentally friendly carriers with specific
attributes. In particular, the immobilization of enzymes on nanocellulose
(CNC), which features a well-organized crystalline structure, favorable
morphology, and properties such as non-toxicity and biocompatibility,
represents a promising approach for enhancing the performance of crucial
industrial enzymes. With this in mind, the main objective of this study is to
develop an efficient preparation of immobilized xylanase for the production
of potentially prebiotic xylo-oligosaccharides (XOS) using xylan extracted
from sunflower meal (SFM) as a substrate. Specifically, two strategies for
immobilizing xylanase on amino-modified nanocellulose (Amino-CNC) will
be employed: adsorption and covalent binding via glutaraldehyde
crosslinkin
Unlocking the Potential Use of Protein From Pumpkin and Spinach Leaves for Dough Fortification: A Comprehensive Investigation Into Dough Rheology and Nutritional Benefits
No full textIn this study, the effects of spinach and pumpkin leaf proteins, as well as the addition of soy protein, on dough rheology were investigated. Changes in rheological properties were attributed to the distinct interactions of proteins, which differ in their functional characteristics—such as solubility and water/oil binding capacity, and structural features, including hydrophobicity and sulfhydryl group content. The dough water absorption capacity increased from 52.6 ± 0.21% to 57.6 ± 0.33%, 55.5 ± 0.42%, and 53.1 ± 0.12% when soybean, spinach, and pumpkin leaf proteins were incorporated into wheat flour at 5% w/w, respectively. In addition to improved water absorption, changes in dough development time, dough stability, viscosity, and the shelf life of the final product were observed as a result of the incorporation of these plant proteins. A higher content of free sulfhydryl groups observed in pumpkin (49.07 ± 1.03 µmol/g protein) and spinach leaf proteins (58.19 ± 0.49 µmol/g protein) was associated with a noticeable reduction in dough development time and stability compared to soy protein, where a considerably lower free sulfhydryl content (6.21 ± 0.21 µmol/g protein) was measured. The formation of a dough with higher mixing stability was attributed to hydrophobic interactions between soy proteins and similarly hydrophobic gluten. Significantly higher polyphenol content and biological activity were exhibited by dough enriched with pumpkin and spinach leaf proteins compared to dough made with wheat flour and fortified with soy protein. In addition, the essential amino acid profile of the enriched dough was notably improved through the addition of these plant-based proteins to wheat flour
The Mechanical Properties of Erythrocytes Are Influenced by the Conformational State of Albumin
No full textThe mechanical stability and deformability of erythrocytes are vital for their function as they traverse capillaries, where shear stress can reach up to 10 Pa under physiological conditions. Human serum albumin (HSA) is known to help maintain erythrocyte stability by influencing cell shape, membrane integrity, and resistance to hemolysis. However, the precise mechanisms by which albumin exerts these effects remain debated, with some studies indicating a stabilizing role and others suggesting the opposite. This review highlights that under high shear rates, albumin molecules may undergo unfolding due to normal stress differences. Such structural changes can significantly alter albumin’s interactions with the erythrocyte membrane, thereby affecting cell mechanical stability. We discuss two potential scenarios explaining how albumin influences erythrocyte mechanics under shear stress, considering both the viscoelastic properties of blood and those of the erythrocyte membrane. Based on theoretical analyses and experimental evidence from the literature, we propose that albumin’s effect on erythrocyte mechanical stability depends on (i) the transition between unfolded and folded states of the protein and (ii) the impact of shear stress on the erythrocyte membrane’s ζ-potential. Understanding these factors is essential for elucidating the complex relationship between albumin and erythrocyte mechanics in physiological and pathological conditions
Frontiers in Surface Engineering: Shaping the Next Generation of Titanium-Based Biomedical Implants
No full textTitanium and its alloys have become the leading metallic materials for biomedical applications due to their favourable mechanical and physical properties, corrosion resistance, and biocompatibility. However, despite these advantages, challenges such as insufficient bioactivity, limited wear resistance, and inadequate biomechanical stability in physiological environments necessitate further improvements. Over the past decade, multifunctional surface modification techniques have become indispensable treatments in the processing of titanium-based biomaterials to optimize their performance. This study aims to review and analyze our and recent research on the application of surface modification methods in processing titanium-based biomaterials and the ability to enhance characteristics such as biocompatibility, corrosion resistance, and surface modulus of elasticity, with a focus on using advanced hybrid modification methods: severe plastic deformation and surface modification. Surface modification methods such as anodic oxidation, plasma electrolytic oxidation, laser surface treatment, chemical etching, and physical and chemical vapour deposition have been shown to improve surface topography, wettability, biomechanical interactions, and reduce bacterial adhesion. These improvements lead to increased corrosion and wear resistance, key factors for the long-term success of orthopaedic, dental, and cardiovascular implants. Anodic oxidation is a surface modification technique that allows precise control of surface morphology and characteristics, significantly enhancing the biological, mechanical, and corrosion behaviour of metallic implants. Furthermore, advanced hybrid methods, including the combination of severe plastic deformation and anodic oxidation, have demonstrated synergistic effects producing nanostructured surfaces with superior functional properties. Surface modification engineering is a critical component in the development and processing of next-generation titanium-based biomaterials
Shear-stress-induced swirling flow in biological systems
No full textSwirling motion is an essential phenomenon that significantly influences numerous biological processes, such as
the mixing of molecular components within living cells, nutrient transport, the structural changes of the cytoskeletons of contractile cells and the rearrangement of multicellular systems caused by collective cell migration.
The dynamical relationship between subcellular and supracellular rearrangements enhances cell migration and
contributes to tissue homeostasis. However, the basic mechanisms that drive swirling motion in biological
contexts remain a matter of ongoing inquiry. Several complex biological systems, including synovial fluid, blood,
mucus, cytoskeleton, and epithelial and mesenchymal multicellular systems, are examined in the context of
possible swirling motion. Despite their diverse structures and fluid properties, they all exhibited swirling
behaviour. Shared characteristics among these systems include: (i) a heterogeneous distribution of density and
mechanical stress, (ii) viscoelastic properties, (iii) anisotropic behaviour, and (iv) non-uniform flow patterns.
This multifaceted phenomenon is analysed through the integration of experimental findings from the existing
literature with modelling considerations, aiming to identify the primary physical factors that contribute to the
occurrence of swirling motion such as: lift force and normal stress differences that appear as a consequence of
generated shear stress
Can mineralogy explain weathering and erosion patterns in badlands?
No full textBadlands are dynamic landscapes with limited vegetation, minimal human activity, and in general very active geomorphic processes. As the formation and activity of badlands is influenced by factors such as lithology, weathering, and erosion, this study investigates how mineralogical and physicochemical properties influence weathering and erosion patterns in badlands, focusing on sediment responses under similar climatic conditions. Three unweathered samples with different mineralogical contents were collected from the Vallcebre and Bagà badlands in the Catalan Pyrenees, NE Spain, a region characterized by a humid Mediterranean climate. In addition to quartz and calcite as the dominant minerals, one unweathered sample contained smectite and gypsum, the second smectite, and the third neither smectite nor gypsum. The laboratory experiment for climate simulation was designed so that each sample contained two sub-samples, from which one was exposed to rain and the second to snow. In the first part, the samples were placed in a climate chamber at a temperature of -3 °C after rain (~140 ml) or snow (~150 g) had been simulated. After 15 cycles, in the second part of the experiment, all samples were exposed to rain (~140 ml) and placed in a climate chamber at a temperature of 50 °C. These treatments were repeated 8 times. Throughout the experiment, samples were photographed after each cycle to observe surface changes, while the leached solution was collected and its volume, pH, electrical conductivity (EC), and ion concentrations were measured. Additional analyses were performed to assess changes in morphology, mineralogy, chemical composition, and porosity. Results highlighted the high specific surface area of the smectite-rich samples and confirmed microstructural changes. Variations in pore volume and size distribution emphasized the relationship between mineralogical composition and susceptibility to weathering. The results showed that snow is a more destructive agent compared to rain, especially for smectite-rich samples. As the presence of gypsum increases the weathering resistance of the material, the sample with smectite and gypsum showed a lower degree of decomposition than the sample with only smectite, while the sample without smectite and gypsum showed the least decomposition of the structure. In addition, the sample with smectite and gypsum showed significantly different values for the pH value and the EC value of the leachate. The sulphate concentration was highest in the sample with smectite and gypsum, which is a consequence of the dissolution of the gypsum. These results emphasize the crucial role of mineralogical and physicochemical properties in controlling weathering and erosion processes in badlands. By linking sediment properties to degradation processes under different climatic conditions, this study offers insights into the dynamics of badlands and provides information for predictive modelling of land degradation under climate change
Enzyme-assisted production of prebiotics for topical application and determination of their structural and functional properties
No full textU okviru ove doktorske disertacije izvršena je konvencionalna i enzimski potpomognuta ekstrakcija fitohemikalija iz različitog bobičastog voća i tropova bobičastog voća primenom zelenih rastvarača u cilju dobijanja ekstrakata sa dermalnim prebiotskim potencijalom. Optimizacijom uslova enzimski potpomognute ekstrakcije dobijeni su vodeni ekstrakti koji su pored bogatog polifenolnog sastava i izražene antioksidativne aktivnosti, imali i bolju prebiotsku aktivnost u odnosu na ekstrakte dobijene konvencionalnom metodom ekstrakcije. Kao najbolji izdvojili su se ekstrakti crne ribizle i tropa maline, koji su pokazali visok stepen stimulacije koagulaza negativne bakterije Staphylococcus epidermidis, stalnog člana mikrobiote kože, uz istovremenu inhibiciju patogenih bakterija Staphylococcus aureus i Cutibacterium acnes. Korišćenjem in vitro stratum corneum modela kože i uzorka mikrobiote kože sa atopijskim dermatitisom, pokazano je da isti ekstrakti stimulišu rast koagulaza negativnih bakterija, čime je potvrđena njihova sposobnost modulacije sastava mikrobiote kože u korist željenih bakterija. Ekstrakti crne ribizle i tropa maline dobijeni enzimski potpomognutom ekstrakcijom i eutektičkim smešama na bazi betaina i propilen glikola ili glicerola, imali su izraženiju prebiotsku aktivnost, usled združenog delovanja sastojaka samih smeša i fitohemikalija prisutnih u ekstraktima. Eksperimenti transdermalne difuzije polifenola ekstrakta crne ribizle iz kozmetičkih formulacija, pokazali su da je hidrogel najpogodnija formulacija za topikalnu isporuku polifenola, jer ostaju na površini kože gde mogu ispoljiti svoju aktivnost. Na kraju, frakcije bogate pektinima dobijene iz tropa crne ribizle zaostalog nakon ekstrakcije fitohemikalija, pokazale su dobra tehno-funkcionalna svojstva za primenu u kozmetičkim proizvodima, kao i prebiotski potencijal.Within this doctoral dissertation, the conventional and enzyme-assisted extraction of phytochemicals from different berries and berry pomaces using green solvents was performed to obtain extracts with skin prebiotic potential. Aqueous extracts obtained under the optimized condition of enzyme-assisted extraction had higher polyphenol concentration and stronger antioxidant activity, as well as better prebiotic activity compared to extracts obtained by the conventional extraction method. Blackcurrant and raspberry pomace extracts stood out as the best, showing a high degree of stimulation of the coagulase-negative bacteria Staphylococcus epidermidis, a resident member of the skin microbiota, with simultaneous inhibition of the pathogenic bacteria Staphylococcus aureus and Cutibacterium acnes. Using an in vitro stratum corneum skin model and a microbiota sample of skin with atopic dermatitis, it was shown that the same extracts stimulate the growth of coagulase-negative bacteria, thus confirming their ability to modulate the composition of the skin microbiota in favor of the beneficial bacteria. Blackcurrant and raspberry pomace extracts obtained by enzyme-assisted extraction and eutectic mixtures based on betaine and propylene glycol or glycerol had a more pronounced prebiotic activity, due to the joint action of the ingredients of the mixture and phytochemicals present in the extracts. Experiments of transdermal diffusion of polyphenols of blackcurrant extract from cosmetic formulations showed that hydrogel is the most suitable formulation for topical delivery of polyphenols because they remain on the surface of the skin where they can exert their activity. Finally, the fractions rich in pectin obtained from blackcurrant pomace remaining after extraction of phytochemicals, showed good technofunctional properties for application in cosmetic products, as well as skin prebiotic potential