Macedonian Journal of Chemistry and Chemical Engineering

Impact of oil extraction method and genotype on the techno- and bio-functional properties of Camelina (Camelina sativa L.) seed cake

Ivan Savić — 2026-06-30

Oilseed cakes are significant by-products of the oil-processing industry with considerable potential for further valorization. This study systematically investigated the effects of genotype (NS Zlatka and NS Slatka) and oil extraction method (Soxhlet extraction with n-hexane versus cold pressing) on the nutritional composition, techno- and bio-functional properties of camelina (Camelina sativa L.) seed cake. Basic nutritional parameters, water and oil absorption capacities, as well as gelling, foaming, and emulsifying properties, were evaluated. The results demonstrated that both genotype and oil extraction method significantly affected the composition and techno-functional properties of camelina seed cake (p < 0.05). Cakes obtained using Soxhlet extraction exhibited higher protein (41.80–42.50 %) and ash (6.11–6.32 %) contents, along with enhanced water (573–699 %) and oil (218–244 %) absorption capacities. In contrast, the resulting cold-pressed cakes retained a higher proportion of residual oil (14.80–16.20%). Although total phenolic content was relatively similar among samples (approximately 0.55 g gallic acid equivalent (GAE)/100 g dry matter), the qualitative and quantitative composition of individual phenolic compounds varied markedly depending on genotype and oil extraction method. The cold-pressed cakes, particularly the NS Zlatka genotype, were characterized by high gallic acid content (140.58 mg/100 g dry matter) and the most pronounced antiradical activity (IC₅₀ = 0.080 mg/ml) determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. These findings indicate that Soxhlet-extracted cakes are superior for applications requiring high protein content and hydration properties, while cold-pressed cakes from the NS Zlatka genotype offer higher antioxidant potential. This study provides a strategic basis for selecting specific genotypes and processing methods to tailor the functional profile of camelina by-products for the food and pharmaceutical industries.

Phytochemical characterization, antioxidant properties, and molecular docking analysis of Cistanche tinctoria from the Algerian Sahara

Nesrine Sadaoui-Smadhi — 2026-06-30

Cistanche tinctoria is a medicinal plant traditionally used for its tonic and antioxidant properties; however, its bioactive profile remains insufficiently characterized. This study aimed to investigate the chemical composition and antioxidant potential of a hydromethanolic extract of C. tinctoria, and to explore the interactions of its major phenolic compounds with enzymes involved in oxidative stress-related processes. The total phenolic and flavonoid contents were determined using spectrophotometric methods, while chromatographic profiling and quantification of individual constituents were performed by high-performance liquid chromatography coupled with a photodiode array detector (HPLC-PDA). The antioxidant activity of the extract was evaluated using the DPPH radical scavenging, ABTS radical scavenging, cupric reducing antioxidant capacity, and ferric reducing antioxidant power assays. HPLC-PDA analysis revealed the presence of phenolic compounds, with acteoside and chicoric acid identified as the major constituents. The extract exhibited strong radical scavenging and reducing activities. Molecular docking studies suggested favorable interactions between the major phenolic compounds and protein targets associated with oxidative stress. In addition, in silico absorption, distribution, metabolism, excretion, and toxicity predictions suggested acceptable physicochemical and pharmacokinetic properties. Overall, this integrated chemical and computational approach supports the antioxidant potential of C. tinctoria and highlights its value as a promising source of bioactive natural compounds.

Eeffect of modified atmosphere packaging (MAP) on the shelf life and quality of gluten-free vegan carrot cake

Aneta Stajikj — 2026-07-02

The objective of this study was to investigate the effect of different packaging gas compositions: air (AIR), 100 % N₂ (inert atmosphere, INE), and 30 % CO₂/70 % N₂ (modified atmosphere, MAP), on the quality of gluten-free vegan carrot cake stored at room temperature (20 ± 2 °C) for 35 days. Physicochemical properties, microbiological stability, and sensory characteristics of the cakes were assessed. Among the tested conditions, the MAP treatment showed the most favorable overall performance. Sensory evaluation indicated that MAP-packaged samples achieved the highest scores (4.5 out of 5) even after 35 days of storage. Microbiological stability remained within acceptable limits (< 3 log colony-forming units, cfu/g sample) under both MAP and INE, while AIR-packaged samples exhibited faster spoilage. Moisture loss was significantly reduced under nitrogen packaging (12.21–15.51 %) compared with air-packaged samples (10–25 %), further indicating improved product stability. These results demonstrate that the composition of packaging gases plays a crucial role in maintaining product quality and stability. This study underscores the significant potential of MAP for the development of new plant-based, gluten-free bakery products with extended shelf life and preserved quality.

Acronyms in Macedonian scientific and professional chemical literature

Ivona Sofronievska — 2026-07-02

Acronyms are frequently used in chemical literature. However, a major inconsistency exists in their usage regarding the choice between Cyrillic and Latin scripts, as well as how they are written and pronounced. This paper provides practical recommendations for the harmonized use of acronyms in Macedonian professional and scientific chemical literature.

Enhancing TiO2 photocatalytic efficiency through the synergistic effect of titania/ceria binary oxide and silver doping

Marija Vasić Jovev — 2026-06-30

In this study, a modified sol–gel method was used to synthesize pure TiO₂ and TiO₂/CeO₂-based materials, followed by the loading of 3 wt.% silver ions onto the catalyst surfaces using a wet-impregnation method. All synthesized and modified catalysts were characterized using Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques to analyze their textural, morphological, and structural properties. The photocatalytic activity of these materials was evaluated for the degradation/decolorization of crystal violet (CV) dye under ultraviolet (UV) irradiation. Moreover, the effects of various process parameters, including initial dye concentration, catalyst amount, and UV wavelength, on photocatalytic efficiency were analyzed. The results indicated that the addition of CeO₂ and Ag into the TiO₂ catalyst significantly enhanced the photocatalytic activity compared with pure TiO₂ under identical experimental conditions. Further analysis of the photocatalytic process demonstrated that the TiO₂/CeO₂ binary oxide catalyst, as well as Ag-doped samples (TiO₂/Ag and TiO₂/CeO₂/Ag), exhibited improved photocatalytic performance relative to pure TiO₂.

Computational insights into PFOS and PFOA encapsulation within a covalent "cage-of-cages" architecture

Avni Berisha — 2026-06-30

The widespread contamination of water by per- and polyfluoroalkyl substances (PFAS) demands the development of efficient and selective removal strategies. In this study, we use computational methods to investigate the potential of a covalently bonded "cage-of-cages" molecular architecture for PFAS sequestration, employing density functional theory (DFT), molecular dynamics (MD), nudged elastic band (NEB) calculations, and noncovalent interaction (NCI) analyses. DFT calculations show stronger binding of perfluorooctanesulfonic acid (PFOS) (–33.07 kcal/mol) relative to perfluorooctanoic acid (PFOA) (−24.63 kcal/mol), primarily driven by van der Waals and electrostatic interactions within the confined cage interior. MD simulations confirm the stable confinement of both PFAS molecules in water, while NEB calculations reveal a higher relative desorption energy barrier for PFOS (109.18 kcal/mol) compared with PFOA (99.84 kcal/mol), implying stronger retention of PFOS within the cage cavity. Collectively, these findings demonstrate that hierarchical molecular cages served as promising supramolecular platforms for PFAS sequestration, offering a mechanistic computational basis for future experimental validation and rational adsorbent design.

Decoding the features of important biochemical multistep electron-transfer pathways through the signatures of two-step double-regenerative electrochemical mechanism in square-wave voltammetry

Rubin Gulaboski — 2026-06-30

Results from theoretical analyses of a two-step double-regenerative electrochemical mechanism (schematically designated as EC’EC” mechanism), examined for the first time under conditions of square-wave voltammetry, are presented. The primary emphasis is on the relevance of this complex mechanism for getting a more comprehensive understanding of analogous mechanistic pathways that frequently operate under physiological conditions. Such complex mechanistic schemes are typical of many biologically important pathways in which coupled electron-transfer steps are linked to homogeneous regenerative reactions mediated by catalytic substrates, enzymes, stable radical species, or some redox cofactors. Through systematic analysis of the forward and backward square-wave current components, the role of regenerative loops associated with both electron-transfer steps in affecting the voltammetric response and generating distinct electrochemical–catalytic signatures is elucidated. The proposed framework encompasses for the first time the interplay between electron-transfer kinetics, chemical regeneration rates, and mass transport within the time scale imposed by square-wave excitation signal. The results establish a useful framework for a unified mechanistic interpretation of complex bioelectrochemical systems, while offering a robust theoretical basis for kinetic analyses of multistep redox pathways relevant to metabolic processes, enzymatic catalysis, and redox signaling in living organisms.

The influence of low-concentration additives of dimethyl sulfoxide and formamide on the stability and performance of lithium bis(trifluoromethanesulfonyl)imide-based electrolyte for lithium-ion batteries

Amjad Abedelqader — 2026-06-30

The development of advanced electrolytes is essential for improving the stability and safety of lithium-ion batteries (LIBs). This study systematically investigated the effect of low concentrations of two polar additives, dimethyl sulfoxide (DMSO) and formamide (FA), in a lithium bis(trifluoromethane-sulfonyl)imide (LiTFSI) electrolyte with ethylene carbonate and diethylene carbonate (EC/DEC, 1:1 v/v). Electrolytes containing 2.5 wt% of each additive were prepared and evaluated for ionic conductivity, electrochemical stability window (ESW), Li-ion transference number, and cycling performance in graphite||Li⁺ half-cells relative to the blank electrolyte. Ionic conductivity measurements showed that both DMSO and FA reduced conductivity due to higher viscosity and stronger Li⁺ solvation. Linear sweep voltammetry (LSV) indicated that while the blank electrolyte exhibited a wide ESW of 5.45 V, the addition of 2.5 wt% DMSO and FA slightly narrowed the window to 5.15 V and 4.98 V, respectively. Both additives increased the Li-ion transference number compared to the blank. Cyclic voltammetry (CV) revealed that DMSO improved interfacial reversibility, whereas FA induced quasi-capacitive behavior with suppressed faradaic processes. However, galvanostatic cycling demonstrated that both additives led to poor coulombic efficiency and unstable cycling, likely due to incompatibility with the graphite anode. Galvanostatic charge-discharge (GCD) results further indicated that low concentrations of DMSO and FA did not enhance long-term cycling stability, probably due to irregular solid electrolyte interphase (SEI) formation, although they may hold potential for high-voltage cathode applications.

Inquiry-based learning in stereochemistry: Strengthening 3D visualization and conceptual understanding

Aleksandra Naumoska — 2026-06-30

This study examined the impact of cooperative inquiry‑based learning (IBL) using hands‑on molecular models on the learning of organic stereochemistry in a high school setting. In this approach, teacher support is minimal, allowing students to independently construct new concepts while reviewing previously acquired knowledge. The research was conducted with two parallel groups: an experimental group, which participated in the IBL interactive activities, and a control group, which followed a traditional instructional approach. The experimental group engaged in a three‑phase learning cycle of exploration, concept formation, and application. Activities were conducted through cooperative small‑group work, encouraging students to discuss ideas and compare molecular structures. Students constructed and analyzed 3D models of organic stereoisomers, applying their observations to formulate rules for different types of stereoisomerism and to visualize molecular structures more effectively. After completing the activities, students completed a questionnaire regarding their attitudes and experiences, as well as a knowledge test. The questionnaire revealed that students found the activities motivating, useful, and accessible, highlighting increased engagement, improved conceptual understanding, and a preference for interactive model‑based approaches over traditional lectures. Both groups completed a knowledge test, and the results showed that the experimental group scored significantly higher. Statistical analysis confirmed that these differences were statistically significant. These findings indicate that cooperative IBL using hands‑on molecular models is an effective teaching strategy for improving conceptual understanding, mastery of stereochemical concepts, and the development of higher-order thinking. Moreover, students demonstrated an enhanced ability to apply learned concepts and terminology in new and more complex contexts, indicating a deeper and more lasting understanding of the material.

Discriminant analysis of atorvastatin calcium trihydrate raw materials from different providers by Raman spectroscopy and X-ray diffraction in conjunction with two-trace two-dimensional correlation

Dragana Trajkovikj Terziski — 2026-06-30

Two-trace two-dimensional (2T2D) correlation of Raman spectroscopy and X-ray diffraction data was applied for discriminant analysis of atorvastatin calcium trihydrate raw material samples from two different manufacturers. Single-parameter trace similarity measures, such as cosine distance and Pearson's correlation coefficient, often fail to properly reflect the differences between complex two-dimensional traces containing numerous signals. The discriminant potential of asynchronous 2T2D correlation maps constructed from Raman spectra and X-ray diffraction patterns (XRD) proved exceptional for resolving overlapping bands from multiple species and revealing complementary phase composition information in raw material samples (including active pharmaceutical ingredients – APIs). Under stringent regulatory demands for quality assurance, batch uniformity, and trace impurity detection, this method provides a practical, complementary QC routine that enables rapid polymorph identification. This study demonstrates the application of 2T2D correlation analysis integrated with Raman spectroscopy and XRD as a feasible, complementary method for quality control and assurance of APIs.

Quality by design approach to the development of metformin hydrochloride granules with immediate and prolonged release

Maja Todeska — 2026-06-30

Metformin hydrochloride (MHCl) is administered at high doses and requires robust formulation strategies to balance rapid drug availability with controlled-release performance. This study applied a Quality by Design (QbD) framework to develop immediate-release (IR) and prolonged-release (PR) MHCl granules and to evaluate the impact of binder selection on product quality and release behavior. Formulations were produced via wet granulation using polyvinylpyrrolidone (PVP), gelatin, and pregelatinized starch 1500 as binders. PR granules were further coated with Eudragit® RS/RL using a fluid-bed process. Risk assessment tools (Ishikawa and FMECA) guided the identification of critical quality attributes (CQAs), critical material attributes (CMAs), and critical process parameters (CPPs). Compatibility studies confirmed the absence of drug–excipient interactions. All IR formulations demonstrated rapid dissolution (> 90% release within 5 min). Uncoated PR granules exhibited partial release control, while coated formulations showed binder-dependent differences in particle size distribution and dissolution performance. The gelatin-based PR formulation provided the most consistent release profile and the closest alignment with United States Pharmacopeia (USP) extended-release criteria, as it demonstrated low variability and minimal intermediate-point deviations. The study confirmed that binder selection was a high-impact critical material attribute for achieving robust prolonged-release MHCl granules within a QbD-driven development strategy.

Microwave-assisted green fabrication of nickel foam–reduced graphene oxide–nickel sulfide nanocomposite: Structural, spectroscopic, and electrochemical performance evaluation for supercapacitor applications

Prabaharan Panchanathan — 2026-06-30

A microwave-assisted green synthesis route was employed to fabricate a nickel foam–reduced graphene oxide–nickel(II) sulfide (Ni foam–rGO–NiS) nanocomposite using Coccinia grandis leaf extract as the bio-reducing and stabilizing agent for supercapacitor applications. The Ultraviolet - Visible (UV) spectrum revealed an absorption peak of 239 nm (rGO) and 313 nm (NiS), confirming the formation of a composite that facilitates efficient electron transfer between the two components, potentially reducing the band gap energy. Fourier Transform Infrared spectra (FTIR) confirmed successful loading of NiS nanoparticles onto rGO, with associated phytochemical functional groups acting as reducing, capping, and stabilizing agents. X-ray Diffraction (XRD) patterns validated formation of hexagonal NiS and reduction in the sheet structure of rGO, thereby elucidating the nature of the nanocomposite. The average crystallite size, estimated using the Debye–Scherrer equation, was approximately 2–5 nm (NiS) and approximately 30.4 nm (rGO). The surface morphology of the nanocomposite displayed an exfoliated wrinkled sheet structure, with NiS particles uniformly dispersed throughout. Elemental analysis verified that the material had achieved the expected purity levels, with no detectable impurities, while the Dynamic Light Scattering (DLS) indicated a particle size of approximately 100 nm in solution. The Ni foam–rGO–NiS electrode demonstrated significantly enhanced electrochemical performance. Cyclic voltammetry conducted at the same scan rate revealed intense redox peaks, thus confirming pseudocapacitive behavior. Electrochemical impedance spectroscopy (EIS) indicated low charge-transfer resistance with high electrochemical activity. This electrode achieved a high specific capacitance of approximately 633.3 F g^–¹ at 1 A g^–¹ and approximately 422.2 F g^–¹ at 5 A g^–¹, as well as exhibiting good rate capability and cycling stability, with 80–85% capacitance retention over 3000 cycles. The synergistic combination of highly conductive rGO, redox-active NiS, and porous Ni foam enhanced charge storage and transportation. The prepared green-synthesized, reduced graphene oxide–nickel(II) sulfide nanocomposite is proposed as a promising electrode nanomaterial for supercapacitor applications.