1. Ellagitannin content in extracts of the chestnut wood aesculusTaja Žitek Makoter, Maša Knez Marevci, Željko Knez, 2024, original scientific article Keywords: antioxidant activity, chestnut wood, conventional extraction, extraction, fractionation, polyphenols, tannins, ultrasound extraction Published in DKUM: 05.09.2024; Views: 70; Downloads: 5 Full text (1,27 MB) |
2. Reinforcing ethyl cellulose aerogels with poly(lactic acid) for enhanced bone regenerationGabrijela Horvat, Jan Rožanc, Uroš Maver, Matjaž Finšgar, Željko Knez, Zoran Novak, 2024, original scientific article Abstract: Developing double porous biodegradable and biocompatible scafolds that can incorporate and release drugs in a controlled manner holds immense potential in regenerative medicine. This study presents a synthesis method for preparing a macro-mesoporous scafold, where poly(lactic acid) adds to the macroporous region and mechanical properties, and ethyl cellulose adds to the surface area (182 m2 /g). High surface area enables the incorporation of model drug indomethacin with an entrapment efciency of 17.0% and its later controlled release profle. The resulting scafold has desirable mechanical properties in the range of a natural trabecular bone with a compressive modulus of 22.4 MPa. The material is stable in the simulated body fuids for 120 days before the slow degradation starts. In vitro studies demonstrate the material’s ability to support bone cell adhesion, proliferation, and diferentiation, promoting osteogenic activity. Overall, the unique combination of poly(lactic acid) and ethyl cellulose produces advanced materials with tailored macro and mesopore properties, remarkable mechanical properties, optimal degradation rate, and drug delivery potential, making it a promising candidate for bone scafolds in regenerative medicine and tissue engineering Keywords: bio composite, polymer-matrix composites (PMCs), polymers, porosity/voids, secondary ion mass spectrometry Published in DKUM: 23.08.2024; Views: 130; Downloads: 6 Full text (2,87 MB) |
3. Antibacterial Komagataeibacter hansenii nanocellulose membranes with avocado seed bioactive compoundsKaja Kupnik, Mateja Primožič, Vanja Kokol, Željko Knez, Maja Leitgeb, 2024, original scientific article Keywords: bacterial nanocellulose membrane, avocado seed extracts, extraction, swelling, release, antibacterial activity Published in DKUM: 23.08.2024; Views: 70; Downloads: 4 Full text (1,80 MB) |
4. Multifunctional iron oxide nanoparticles as promising magnetic biomaterials in drug elivery : a ǂreviewKatja Vasić, Željko Knez, Maja Leitgeb, 2024, review article Keywords: multifunctional biomaterials, bio-composites, nanocarriers, magnetic nanoparticles, modification, drug delivery Published in DKUM: 20.08.2024; Views: 72; Downloads: 3 Full text (5,66 MB) |
5. Mango peels as an industrial by-product: a sustainable source of compounds with antioxidant, enzymatic, and antimicrobial activityNika Kučuk, Mateja Primožič, Petra Kotnik, Željko Knez, Maja Leitgeb, 2024, original scientific article Abstract: Plant waste materials are important sources of bioactive compounds with remarkable health-promoting benefits. In particular, industrial by-products such as mango peels are sustainable sources of bioactive substances, with antioxidant, enzymatic, and antimicrobial activity. Appropriate processing is essential to obtain highly bioactive compounds for further use in generating value-added products for the food industry. The objective of the study was to investigate and compare the biological activity of compounds from fresh and dried mango peels obtained by different conventional methods and unconventional extraction methods using supercritical fluids (SFE). The highest total phenolic content (25.0 mg GAE/g DW) and the total content of eight phenolic compounds (829.92 µg/g DW) determined by LC-MS/MS were detected in dried mango peel extract obtained by the Soxhlet process (SE). SFE gave the highest content of proanthocyanidins (0.4 mg PAC/g DW). The ethanolic ultrasonic process (UAE) provided the highest antioxidant activity of the product (82.4%) using DPPH radical scavenging activity and total protein content (2.95 mg protein/g DW). Overall, the dried mango peels were richer in bioactive compounds (caffeic acid, chlorogenic acid, gallic acid, catechin, and hesperidin/neohesperidin), indicating successful preservation during air drying. Furthermore, outstanding polyphenol oxidase, superoxide dismutase (SOD), and lipase activities were detected in mango peel extracts. This is the first study in which remarkable antibacterial activities against the growth of Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) were evaluated by determining the microbial growth inhibition rate after 12 and 24 h incubation periods for mango peel extracts obtained by different methods. Ethanolic SE and UAE extracts from dried mango peels resulted in the lowest minimum inhibitory concentrations (MIC90) for all bacterial species tested. Mango peels are remarkable waste products that could contribute to the sustainable development of exceptional products with high-added value for various applications, especially as dietary supplements. Keywords: mangifera indica, peels, bioactive substances, LC-MS/MS, proteins, enzymes, antibacterial activity Published in DKUM: 12.08.2024; Views: 104; Downloads: 8 Full text (6,49 MB) |
6. Alginate beads with encapsulated bioactive substances from mangifera indica peels as promising peroral delivery systemsNika Kučuk, Mateja Primožič, Željko Knez, Maja Leitgeb, 2024, original scientific article Abstract: Since various bioactive substances are unstable and can degrade in the gastrointestinal tract, their stabilization is crucial. This study aimed to encapsulate mango peel extract (MPE) into edible alginate beads using the ionotropic gelation method for the potential oral delivery of bioactive substances. Mango peels, generally discarded and environmentally harmful, are rich in health-promoting bioactive substances. The alginate beads were examined for entrapment efficiency, particle size, morphology, thermal stability, physiochemical interactions, release profile under gastrointestinal conditions, and antibacterial efficacy. The study demonstrated the successful encapsulation of MPE with an efficiency of 63.1%. The in vitro release study showed the stability of the alginate beads in simulated gastric fluid with a maximum release of 45.0%, and sustained, almost complete release (99.4%) in simulated intestinal fluid, indicating successful absorption into the human body. In both fluids, the MPE release followed first-order kinetics. Encapsulation successfully maintained the antibacterial properties of MPE, with significant inhibitory activity against pathogenic intestinal bacteria. This is the first study on MPE encapsulation in alginate beads, presenting a promising oral delivery system for high-added-value applications in the food industry for dietary supplements, functional foods, or food additives. Their production is sustainable and economical, utilizing waste material and reducing environmental pollution. Keywords: alginate beads, encapsulation, Mangifera indica, mango peels, characterization, in vitro release, antbacterial activity Published in DKUM: 02.08.2024; Views: 104; Downloads: 9 Full text (6,98 MB) |
7. Superkritični fluidi za izolacijo in formulacijo bioaktivnih snoviMaša Knez Marevci, Katja Andrina Kravanja, Željko Knez, 2024, review article Keywords: podkritične tekočine, nadkritične tekočine, ekstrakcija, mikronizacija, impregnacija, nanašanje, sterilizacija Published in DKUM: 30.07.2024; Views: 141; Downloads: 22 Full text (401,35 KB) This document has many files! More... This document is also a collection of 1 document! |
8. 20th European Meeting on Supercritical Fluids : Book of Abstracts2024 Abstract: The 20th European Meeting on Supercritical Fluids (EMSF 2024) was hosted by the Faculty of Chemistry and Chemical Engineering of the University of Maribor from 26 May to 29 May 2024 in Maribor, Slovenia. The EMSF 2024 was a joint event of the International Society for the Advancement of Supercritical Fluids (ISASF) and the European Federation of Chemical Engineering (EFCE) Working Party on High Pressure Technology (WP HPT) Event No. 807. This symposium provided an excellent opportunity for engineers, chemists, physicists, food technologists, and biologists to meet and discuss new ideas, review ongoing challenges, present potential solutions, and identify future issues related to high pressure technologies and supercritical fluids. The aim of the meeting was to deepen connections between researchers, establish new contacts, and promote synergies and partnerships between researchers. The symposium presented the latest advances in high-pressure process technologies that can contribute to the further development of the field. Keywords: supercritical fluids, fundamental data, novel materials, industrial applications, research and development Published in DKUM: 24.07.2024; Views: 161; Downloads: 26 Full text (12,44 MB) This document has many files! More... |
9. Extraction of active compounds from mixtures of hemp (Cannabis sativa) with Pants of the Zingiberaceae familyVesna Postružnik, Taja Žitek Makoter, Darko Goričanec, Petra Kotnik, Željko Knez, Maša Knez Marevci, 2023, original scientific article Keywords: supercritical fluid extraction, ultrasound-assisted extraction, hemp, ginger, turmeric, cardamom Published in DKUM: 08.05.2024; Views: 234; Downloads: 13 Full text (2,36 MB) This document has many files! More... |
10. The synthesis, surface analysis, and cellular response of titania and titanium oxynitride nanotube arrays prepared on TiAl6V4 for potential biomedical applicationsKatja Andrina Kravanja, Luka Suhadolnik, Marjan Bele, Uroš Maver, Jan Rožanc, Željko Knez, Maša Knez Marevci, Matjaž Finšgar, 2023, original scientific article Abstract: Titania nanotubes are gaining prominence in the biomedical field as implant materials due to their mechanical durability, nano-rough properties, and positive influence on cellular response. This work aimed to synthesize titania and titanium oxynitride (TieOeN) nano- tubular arrays on TiAl6V4 substrates using an anodic oxidation process followed by annealing in air or by additional nitridation in NH3 atmosphere. Different nanotubular layers of unique morphology and structure were fabricated and investigated using advanced surface analysis and biocompatibility tests. In-depth surface analysis was per- formed by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), 3D profilometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). Cell testing using adipose- derived mesenchymal stem cells and human fetal osteoblasts demonstrated good cell viability, high proliferative capacity, and a favorable overall effect on cell morphology for the TieOeN nanotubes. Keywords: surface analysis, XPS, AFM, tandem ToF-SIMS, titania nanotubes, Ti-O-N nanotubes, anodization Published in DKUM: 07.05.2024; Views: 186; Downloads: 19 Full text (8,31 MB) This document has many files! More... |