Filters
Aktywność biologiczna i profil fenolowy ekstraktu z łupiny orzecha włoskiego
Introduction. Walnut products are widely used. Green fruits, shells, leaves and bark have a high phenolic content and are used in the pharmaceutical and cosmetic industries. Seeds rich in unsaturated fatty acids are used in the food industry. Walnut wood is also valuable. Aim. The aim of the study was to determine the microbiological, antioxidant activity and concentration of phenolic acids of walnut shell extract. Material and methods. The methanol extract of walnut shells from trees growing in Greater Poland was used for the research. The antibacterial activity was determined by the point diffusion method against 7 strains of gram-positive bacteria and 6 strains of gram-negative bacteria. The method with the DPPH radical and the ability to chelate Fe2+ ions were used to determine the antioxidant activity. The content of phenolic compounds in the tested extract was also determined using the chromatographic method. Results. The tested walnut shell extract showed moderate antibacterial activity against gram-positive and gram-negative bacteria and high antioxidant activity in the radical cation test and lower chelating activity in the ferrozine test. Moreover, in the tested walnut shell extract, a higher concentration of phenolic acids, mainly caffeic acid, was determined as compared to the concentration of flavonoids. Conclusions. The tested walnut shell extract showed antiradical activity; therefore, it can be an alternative to synthetic antioxidants. The fact that shells shells are a by-product of the food industry is an added advantage when used in other industries as well.
Color as an Indicator of Properties in Thermally Modified Scots Pine Sapwood
The aim of this study was to determine the dependencies between mechanical properties of modified wood and its color. Within its scope, quantitative changes in color and chemical composition (mass loss, total carbon content, content of extractives and main components of wood), as well as mechanical properties (compressive strength along the grain, strength and modulus of elasticity in longitudinal tension tests, compression across the grain and impact resistance) of the modified Scots pine sapwood, were determined. Modifications were conducted in the atmosphere of superheated steam (time—4 h, temperature of 130, 160, 190, 220 °C). Thermal modification of wood results in an increase in the modulus of elasticity, a reduction of elasticity, longitudinal tensile strength and compressive strength perpendicular to grain. It was found that color parameters ∆E, ∆L and ∆a are linear functions of the modification temperature. The existence of functional dependencies between mass loss, longitudinal tensile strength, radial modulus of elasticity and parameters of ∆E and ∆L makes it possible to determine these properties of modified wood based on color. In turn, chemical analysis indicated that an increase in the temperature of wood modification caused a decrease of holocellulose and hemicelluloses contents, especially in wood samples modified at 220 °C.
Biological Activity and Chemical Composition of Propolis from Various Regions of Poland
Propolis is one of the bee products, with multiple biological properties used in numerous applications. The research objective was to determine the chemical composition and biological properties (antibacterial, antifungal, antiviral, antioxidant, and cytoprotective activity) of propolis extracts collected from various regions of Poland. The results indicated that the total content of phenols (116.16–219.41 mg GAE/g EEP) and flavonoids (29.63–106.07 mg QE/g EEP) in propolis extracts depended on their geographic origin. The high content of epicatechin, catechin, pinobanksin, myricetin, and acids: vanillic and syringic in propolis samples was confirmed by chromatographic analysis. Moreover, the presence of caffeic acid phenethyl ester was confirmed in all samples. The origin of propolis also influenced the biological properties of its extracts. The propolis extracts were characterized by moderate DPPH free radical scavenging activity (29.22–35.14%), and relatively low ferrous iron chelating activity (9.33–32.32%). The results indicated also that the propolis extracts showed high activity in the protection of human red blood cells against free radicals generated from 2,2’-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The extracts exhibited diversified activity against the tested pathogenic bacteria and limited activity against fungal strains. The research of selected propolis extracts showed that only 2 of 5 examined samples showed moderate activity against HPV (human papillomaviruses) and the activity depended on its geographical distribution.
Chitosan–caffeine formulation as an ecological preservative in wood protection
AbstractNowadays, taking into account environmental degradation, climate changes, as well as, environmentally friendly regulations and increasing ecological awareness of consumers, methods of wood protection without negative impact on the environment are being intensively developed. In this study, a mixture of chitosan and caffeine was proposed as ecological wood preservative. The aim of the research was to evaluate the application of chitosan (medium and high molecular weight) as an agent limiting the leaching of caffeine from the structure of treated wood. The resistance of pine wood treated with chitosan–caffeine preparations and ingredients of these preparations (caffeine and chitosan) to brown rot fungus—Coniophora puteana was assessed. The degree of caffeine leaching from the treated wood was determined by chromatographic analysis (caffeine concentration) and elemental analysis (nitrogen concentration). The results showed that chitosan limited caffeine leaching from wood, which was confirmed by chromatographic analysis and changes in the wood structure observed in FTIR spectra. Moreover, wood treated with chitosan–caffeine preparations showed resistance against C. puteana (mass loss about 0.5%); however, antifungal activity was reduced when treated wood was subjected to leaching with water (mass loss about 10%). The obtained results suggest that the chitosan–caffeine preparations can be promising ecological preservatives for the wood treatment.
Characteristics of Chitosan Films with the Bioactive Substances—Caffeine and Propolis
Chitosan is a natural and biodegradable polymer with promising potential for biomedical applications. This study concerns the production of chitosan-based materials for future use in the medical industry. Bioactive substances—caffeine and ethanolic propolis extract (EEP)—were incorporated into a chitosan matrix to increase the bioactivity of the obtained films and improve their mechanical properties. Acetic and citric acids were used as solvents in the production of the chitosan-based films. The obtained materials were characterized in terms of their antibacterial and antifungal activities, as well as their mechanical properties, including tensile strength and elongation at break. Moreover, the chemical structures and surface morphologies of the films were assessed. The results showed that the solution consisting of chitosan, citric acid, caffeine, and EEP exhibited an excellent antiradical effect. The activity of this solution (99.13%) was comparable to that of the standard antioxidant Trolox (92.82%). In addition, the film obtained from this solution showed good antibacterial activity, mainly against Escherichia coli and Enterococcus faecalis. The results also revealed that the films produced with citric acid exhibited higher activity levels against pathogenic bacteria than the films obtained with acetic acid. The antimicrobial effect of the chitosan-based films could be further enhanced by adding bioactive additives such as caffeine and propolis extract. The mechanical tests showed that the solvents and additives used affected the mechanical properties of the films obtained. The film produced from chitosan and acetic acid was characterized by the highest tensile strength value (46.95 MPa) while the chitosan-based film with citric acid showed the lowest value (2.28 MPa). The addition of caffeine and propolis to the film based on chitosan with acetic acid decreased its tensile strength while in the case of the chitosan-based film with citric acid, an increase in strength was observed. The obtained results suggested that chitosan films with natural bioactive substances can be a promising alternative to the traditional materials used in the medical industry, for example, as including biodegradable wound dressings or probiotic encapsulation materials.
Chitosan-Based Films with Essential Oil Components for Food Packaging
Chitosan-based films show great potential in terms of application in food preservation and are also promising carriers of biologically active ingredients. This paper presents the potential use of chitosan-based films with the addition of essential oil components, e.g., carvacrol, eugenol, and isoeugenol, intended for food packaging. The characteristics of the obtained films were determined, including antibacterial, mechanical, barrier, and structural parameters. In addition, the antibacterial and antioxidant effects of the essential oil components were assessed. Eugenol (44.41%) and isoeugenol (43.56%) showed high antiradical activities, similar to the activity of Trolox (44.33%), which is used as a standard antioxidant. In turn, carvacrol was characterized by the strongest effect against the examined strains of bacteria, both Gram-positive and Gram-negative. The chitosan film with carvacrol showed the most valuable antibacterial and mechanical properties (tensile strength and elongation at break). The antibacterial activities of the chitosan–carvacrol films were higher than that of the carvacrol solution. The inhibition zones of the chitosan–carvacrol films were in the range 29–41 mm (except for Enterococcus faecalis, with an inhibition zone of 15 mm) compared to the inhibition zones of the carvacrol solution (28 mm). The results showed that chitosan is an effective carrier of fragrance compounds, mainly carvacrol. However, all the tested chitosan-based films with the addition of fragrance compounds showed appropriate parameters (biological, mechanical, and barrier), which makes them an ecological alternative to plastics intended for food packaging.
Phosphorus–Nitrogen Interaction in Fire Retardants and Its Impact on the Chemistry of Treated Wood
This work focuses on the changes in the chemical composition of wood caused by impregnation with fire retardants such as guanidine carbonate (GC), urea (U), diammonium phosphate (DAP) and their mixtures. The treated wood was tested using the oxygen index (LOI), Py–GC/MS analysis and FTIR Spectroscopy. The wood was vacuum treated at a pressure of 0.8 MPa for 20 min and then subjected to thermal degradation using the LOI. This way, degraded and nondegraded layers were obtained and ground (0.2 mm). All treatment variants achieved the class of non-flammable materials based on LOI tests; the exception was the 5% urea solution, defined as a flame-retardant material. Using the analytical methods, it was found that cellulose and hemicelluloses undergo the fastest thermal degradation. This study found that the variant protected with a 5% mixture of GC and DAP before and after the degradation process had the best fire-retardant properties regarding cellulose content in the wood. The highest content of anhydrosugars characterised the same variants, the amount of which indicates a slowdown in the degradation process and, consequently, a reduction in the release of levoglucosan during combustion, suggesting potential applications in fire safety.
Biopolymer Paperboard Impregnation Based on Chitosan and Nanocellulose with Addition of Caffeine and Gallic Acid
In this study, the preparation and detailed characterization of a chitosan (CHT) impregnation system modified with cellulose nanofibrils (CNFs) and enriched with bioactive compounds—caffeine (CAF) and gallic acid (GA)—applied to the surface of unbleached paperboard were described. Their mechanical properties (tensile strength, elongation at break, and bursting strength), structural features, and surface barrier parameters (water absorption) were evaluated. The antibacterial activity of the formulations comprising 1% chitosan (1% CHT), 1% chitosan with 1% caffeine (1% CHT/1% CAF), and 1% chitosan with 1% gallic acid (1% CHT/1% GA)—applied to enhance the functionality of the coated paperboard—was additionally assessed. The incorporation of cellulose nanofibrils into the coating matrix markedly improved the mechanical performance of the paperboard, particularly in terms of puncture resistance and elongation at break, while all modified coatings retained high burst strength. Impregnations containing gallic acid or caffeine showed similar mechanical characteristics but improved flexibility without compromising structural integrity. Chitosan solutions containing gallic acid and solutions containing caffeine exhibited activity against the tested Gram-positive (S. aureus, L. monocytogenes) and Gram-negative (E. coli, P. aeruginosa) bacterial strains. Antibacterial analysis showed moderate activity against Gram-positive strains and strong inhibition of Gram-negative bacteria, with the 1% CHT/1% GA impregnation giving the largest zone of growth inhibition around the sample—19 mm in the agar diffusion test—indicating the strongest suppression of E. coli. It was found that incorporation of nanocellulose into the chitosan matrix significantly reduces water uptake by treated paperboard surface, which is critical in the context of food packaging. The best result—Cobb60 value of 32.85 g/m2—was achieved for the 1% CHT/1% CNF formulation, corresponding to an 87% reduction in water absorption compared to the uncoated control. The results obtained in this study indicate a promising potential for the use of these impregnation systems in sustainable packaging applications.
Enhancing Sustainability and Antifungal Properties of Biodegradable Composites: Caffeine-Treated Wood as a Filler for Polylactide
This study investigates the suitability of using caffeine-treated and untreated black cherry (Prunus serotina Ehrh.) wood as a polylactide filler. Composites containing 10%, 20%, and 30% filler were investigated in terms of increasing the nucleating ability of polylactide, as well as enhancing its resistance to microorganisms. Differential scanning calorimetry studies showed that the addition of caffeine-treated wood significantly altered the crystallization behavior of the polymer matrix, increasing its crystallization temperature and degree of crystallinity. Polarized light microscopic observations revealed that only the caffeine-treated wood induced the formation of transcrystalline structures in the polylactide. Incorporation of the modified filler into the matrix was also responsible for changes in the thermal stability and decreased hydrophilicity of the material. Most importantly, the use of black cherry wood treated with caffeine imparted antifungal properties to the polylactide-based composite, effectively reducing growth of Fusarium oxysporum, Fusarium culmorum, Alternaria alternata, and Trichoderma viride. For the first time, it was reported that treatment of wood with a caffeine compound of natural origin alters the supermolecular structure, nucleating abilities, and imparts antifungal properties of polylactide/wood composites, providing promising insights into the structure-properties relationship of such composites.
Correction: Physical and mechanical properties of wood treated with chitosan-caffeine formulations
Chitosan with Natural Additives as a Potential Food Packaging
Recently, the development of materials based on natural polymers have been observed. This is the result of increasing environmental degradation, as well as increased awareness and consumer expectations. Many industries, especially the packaging industry, face challenges resulting from legal regulations. Chitin is the most common biopolymer right after cellulose and is used to produce chitosan. Due to the properties of chitosan, such as non-toxicity, biocompatibility, as well as antimicrobial properties, chitosan-based materials are used in many industries. Many studies have been conducted to determine the suitability of chitosan materials as food packaging, and their advantages and limitations have been identified. Thanks to the possibility of modifying the chitosan matrix by using natural additives, it is possible to strengthen the antioxidant and antimicrobial activity of chitosan films, which means that, in the near future, chitosan-based materials will be a more environmentally friendly alternative to the plastic packaging used so far. The article presents literature data on the most commonly used natural additives, such as essential oils, plant extracts, or polysaccharides, and their effects on antimicrobial, antioxidant, mechanical, barrier, and optical properties. The application of chitosan as a natural biopolymer in food packaging extends the shelf-life of various food products while simultaneously reducing the use of synthetic plastics, which in turn will have a positive impact on the natural environment. However, further research on chitosan and its combinations with various materials is still needed to extent the application of chitosan in food packaging and bring its application to industrial levels.
The high adaptive potential of Abies alba Mill. seedlings – biochemical and physiological studies of succession along the environmental gradient of a Cambrian quarry
Abstract Abies alba Mill. (silver fir) needs specific soil and humidity conditions and seedlings are vulnerable to climatic extremes. Surprisingly, successful seedling establishment has been observed in disturbed habitats like active quarries. We compared 2-year old fir seedlings in three habitats—natural fir forest, disturbed forest, and exposed quarry—to explore the biochemical features that help them endure the first stages of succession in harsh environments. We assessed a range of parameters including reactive oxygen species (ROS) levels, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl reduction), foliar pigments (chlorophylls and carotenoids), C and N contents, nonstructural carbohydrates, phenolics, and cell wall components analyzed via Fourier Transform Infrared (FTIR) spectroscopy, as well as ectomycorrhizal colonization and diversity. The analysis indicated that the fir seedlings were in unexpectedly good physiological condition despite the environmental constraints. Continuous exposure to harsh conditions (stony soils poor in C and N, extreme insolation, potential drought/flooding stress, etc.) was only slightly associated with ROS and antioxidant levels, roots of seedlings were fully mycorrhized, and their roots did not express signals of severe oxidative stress. Only a few seedling features clearly followed the environmental gradient; C (%), ectomycorrhizal fungal richness in roots, and total antioxidant content in stems decreased in harsh environments. Despite the lower chlorophyll levels, seedlings from the quarry had no decrease in C or N foliar levels. These firs did not have impaired N- or C-compound levels. Quarry seedlings had the highest nonstructural carbohydrates in needles and roots, protective foliar shifts (more carotenoids), and stronger stems (more structural carbohydrates, especially lignin). These findings demonstrate strong acclimatization capacity of A. alba seedlings and suggest the existence of stabilizing physiological mechanisms supporting survival in disturbed environments.
Understanding stoichiometric adjustments in a freshwater plant: Responses to sediment and water nutrient dynamics across lake trophic gradients
AbstractDespite ongoing efforts to reduce nutrient inputs, eutrophication continues to disrupt biogeochemical cycles and destabilize freshwater food webs. In this study, we examine the stoichiometric responses of the freshwater plant Myriophyllum spicatum under varied environmental conditions across lakes of differing trophic status. Specimens were collected from lakes with a wide natural range of macro‐ (C, N, P) and micronutrient (Fe, Cu, Zn) concentration in both water and sediments. We applied the ecological stoichiometry framework and analyzed the relationship between nutrient availability (water and sediments) and the elemental composition of M. spicatum's organs (leaves, stems, and roots). The C : N : P ratios in organs were not affected by eutrophication. Instead, all macro‐ and micronutrient concentrations differed between plant organs. N concentration was highest in leaves and roots, indicating uptake from both sources. Furthermore, sediments significantly influenced the plant organs' C, P, and Zn concentration, while nutrients in the water column showed no correlation. Leaves demonstrated flexibility in C and Zn concentrations, negatively correlating with sediment levels of these elements. The concentration of micronutrients was highest in the roots. Our results indicate distinct nutrient allocation strategies for different plant organs: leaves are rich in N to support photosynthesis, stems store C and P, aiding growth and reproduction, and roots accumulate micronutrients Fe, Zn, and Cu. It highlights sediments as a critical nutrient source for M. spicatum, shaping its elemental composition. The relationship between organisms' biochemistry, trophic interactions, and their transformation into dead organic matter is crucial for understanding environmental stress impacts on aquatic ecosystems.
Impact of thermal modification combined with silicon compounds treatment on wood structure
In the present study silicon containing formulations were investigated for their applicability in solid wood modification. Black pine sapwood was thermally modified at 180oC and 200oC (3, 5 and 7 hours) and afterwards,an additional chemical treatment with silicon containing systems (N-2-aminoethyl-3-aminopropyltrimethoxysilane) followed, in an attempt toinvigorate hydrophobicity and durability of wood. Infrared spectroscopy (FTIR) was used to examine the formation of new bonds in the treated materials and atomic absorption spectrometry (AAS) to measure the silane concentration. The results showed a high reactivity between thermally modified wood and organosilicon compounds. The presence of bands representing vibrationsof the Si–O–CH3group in IR spectra of modified wood and after extraction confirms the stable character of the formed bonds between the hydroxyl group of wood and the methoxy groups of organosilanes. Furthermore, reactivity between wood and AE-APTMOS and alkyd resin solution was confirmed by the AAS results. Alkyd resin caused ahigher concentration of silica in wood mass, which increases as the thermal treatment temperature increases. The organosilicon compounds caused a much higher resistance to water washout, revealing permanent binding of silanes to wood mass.
Iron overload consequences for submerged plants stoichiometry, homeostasis and performance
AbstractAccelerated lakes eutrophication is one of the greatest challenges nowadays. To counteract its negative effects, large-scale restoration treatments are carried out worldwide. However, research in this field is mainly focused on the process effectiveness and there is a scarcity of studies concerning the impact of restoration treatments on water organisms and ecosystem homeostatsis. Our microcosm study presents the effects of a phosphorus coagulant (iron [III] chloride) on functional traits changes, oxidative stress and macro- and microelement stoichiometry disturbances in macrophyte Myriophyllum spicatum, a model species inhabiting eutrophic waters. Application of the coagulant to experimental vessels influenced the physicochemical and optical parameters of water and led to significant changes in biogeochemistry. Stoichiometric alterations were reflected by disturbances in the relative contents of macro- (C, N, P, Ca, Mg) and microelements (Fe, Zn, Cu, Co) and induced luxury consumption of available ions. Physicochemical and stoichiometric changes mutually exerted negative influence on M. spicatum functional traits. The parameters of oxidative stress remained at low levels, comparable to the untreated control whereas stoichiometric analysis revealed the activation of mechanisms responsible for minimizing low light stress. The ability of M. spicatum to maintain homeostasis of Cu and Co under simulated chemical water restoration was closely related to high concentrations of Fe and Zn ions, which simultaneously were not subjected to homeostasis control. Thus, chemical lake restoration treatments based on phosphorus coagulants are not as environmentally safe as previously considered and may have far-reaching consequences for the biogeochemical cycle and food web functioning.
Zawartość związków fenolowych oraz pierwiastków w orzechach ziemnych
Introduction. Peanuts also known as arachidic nuts, are a valuable raw material commonly used in the food industry, including in confectionery, for the production of oil or peanut butter. Peanuts are a valuable source of protein and are rich in unsaturated fatty acids. Peanuts also owe their health-promoting properties to the presence of phenolic compounds, which are characterized by wide biological activity, including antibacterial and antifungal activity, as well as catch free radicals, which are the cause of many civilization diseases. Aim. The aim of the study was to determine the content of phenolic compounds as well as macro- and microelements in peanuts. Material and methods. Peanuts were used in the research, in which the concentration of phenolic compounds was determined by high-performance liquid chromatography and the content of macro- and microelements by X-ray fluorescence spectroscopy. Results. The presence of phenolic compounds in peanuts was confirmed, their concentration was very diverse and ranged from 10.85 ng/g for caffeic acid to 5818.67 ng/g for syringic acid. The analysis of the content of macro- and microelements also showed their different content, from a trace amount to 3.55 μg/g for magnesium. Conclusions. The obtained results of the research on the content of phenolic compounds as well as macro- and microelements in arachidic nuts available on the Polish market indicate that they are a valuable source of ingredients with a positive effect on the human body, and thus their consumption may have an impact on preventing the development of many civilization diseases.
