Krastena Nikolova

Unconventional vegetable oils derived from coffee bean ( Coffea spp.), raspberry seeds ( Rubus idaeus ), neem seeds ( Azadirachta indica ), and moringa seeds ( Moringa oleifera ) were comparatively characterized using gas chromatography–mass spectrometry (GC–MS), Fourier-transform infrared spectroscopy (FTIR, 4000–400 cm ⁻¹ ), UV–Vis spectrophotometry, and three-dimensional fluorescence spectroscopy. GC–MS analysis revealed clear differences in fatty acid composition between polyunsaturated and monounsaturated oils. Coffee and raspberry oils were rich in linoleic (C18:2) and α-linolenic (C18:3) acids, whereas moringa oil was dominated by oleic acid (C18:1, >85%) and contained behenic acid (2.9%). The investigated sample labelled as neem oil showed an atypically high α-linolenic acid content (69%). FTIR spectra of coffee and raspberry oils exhibited more pronounced absorption bands associated with unsaturated fatty acid chains. UV–Vis analysis demonstrated substantial differences in visible-range transmittance related to pigment composition. Neem oil showed the lowest transmittance with a characteristic minimum at 674 nm, while raspberry seed oil exhibited the highest transparency. Three-dimensional fluorescence spectroscopy revealed distinct excitation–emission profiles associated with pigment, aromatic, and terpenoid components. The results demonstrated clear relationships between fatty acid composition, degree of unsaturation, and optical behaviour, supporting the potential application of these oils in cosmetic and dermal formulations.

In the present study, the fluorescence spectra of summer savory ( Satureja hortensis L. ) samples originating from ten different regions of Bulgaria were investigated, and the relationship between optical parameters, phenolic composition, and environmental factors (altitude, solar radiation, etc.) was evaluated. The samples were finely ground, and fluorescence spectra were recorded without extraction or dilution using the spectrophotometers AvaSpec-2038 (Avantes), Ocean Optics USB2000. The main phenolic compounds were identified by HPLC, while the total phenolic content and antioxidant activity were determined using the standard spectrophotometric assays as previously reported. Three main excitation–emission regions were distinguished in the obtained excitation–emission matrices (EEMs): λ_ex = 310 nm, λ_em ≈ (330–360) nm – associated with phenolic components; λ_ex = (440–450) nm, λ_em ≈ (455–465) nm – associated with flavonoids; λ_ex = 420 nm, λ_em ≈ (680–730) nm – associated with the state of chlorophyll a and oxidized phenolic compounds, reflecting the presence of photosynthetic pigments and plant metabolic activity. Principal component analysis (PCA) and cluster analysis based on the intensities of the above-mentioned fluorescence maxima revealed two main clusters. The first cluster included samples exhibiting strong “red” fluorescence, whereas the second consisted of samples with lower but relatively uniform fluorescence in the blue–green region. Furthermore, samples originating from higher altitudes showed stronger fluorescence in the blue–green region, suggesting enhanced biosynthesis of phenolic compounds under conditions of increased UV radiation. The obtained results demonstrated that fluorescence spectroscopy using excitation–emission matrices provided an informative spectral fingerprint of phenolic compounds in Bulgarian summer savory samples.

The analytical characterization of essential oils (EOs) is often interpreted primarily in terms of biological variability, although analytical conditions may also affect compositional profiling and data comparability. In this study, the influence of chromatographic conditions on gas chromatography–mass spectrometry (GC–MS) profiling was investigated. Five EOs representing chemically diverse plant matrices, including Pistacia lentiscus (resin and stem) and leaf oils from Salvia rosmarinus, Laurus nobilis, and Thymus vulgaris, were analyzed using two capillary columns with different stationary phases: RTX-5MS (5% phenyl-substituted polysiloxane) and CP-Sil 5 CB (100% dimethylpolysiloxane). Comparative analysis revealed reproducible differences in chromatographic profiles and relative peak-area distribution, particularly within terpene-rich regions containing structurally related compounds. The most pronounced effects were observed for highly volatile monoterpenes, which were underrepresented under CP conditions. These findings demonstrate that chromatographic selectivity and column geometry may affect the semi-quantitative representation of EO profiles and contribute to variability in reported compositions. Overall, the results highlight the importance of carefully controlled analytical conditions in EO characterization.

The release kinetics of functional compounds from active packaging systems plays a crucial role in determining their efficiency, as it directly affects the availability of the incorporated agents and the extension of the product’s shelf life. Therefore, controlled release behaviour is essential for optimizing the functionality of such materials. In the present study, corona treatment was used as a surface modification technique to tailor the release behaviour of polyphenols—curcumin, quercetin, and rutin—from polylactic acid (PLA) films. Polyphenol release was performed in a model medium (3% acetic acid), and the experimental data were fitted using commonly applied kinetic models to elucidate the release mechanism. The results indicate that corona-treated films exhibit significantly accelerated release kinetics and higher cumulative release compared to untreated samples. To interpret the observed behaviour, different surface characterization techniques were applied. Scanning electron microscopy (SEM) revealed only minor changes in the morphology of the uncharged and charged samples, which are unlikely to account for the observed differences in the release behaviour. Fourier transform infrared spectroscopy (FT-IR) confirmed that corona treatment has led to formation of new peaks in PLA spectrum and change in the shape and intensity in PLA–polyphenol loaded films. Contact angle measurements demonstrated increased surface wettability after treatment. These changes are associated with enhanced polymer–medium interactions and improved mobility of the incorporated polyphenols, leading to accelerated release. These findings demonstrate that corona treatment is an effective strategy for tuning the release kinetics of PLA-based systems. The developed materials show strong potential for use in active packaging applications, where controlled release of antioxidant compounds is essential for extending product shelf life.

Yogurt represents a traditional fermented dairy product characteristic of the Balkan Peninsula and is widely consumed in the Republic of Bulgaria. The aim of the present study was to develop omega-3-enriched yogurt. Four yogurts were produced: one control sample and three experimental variants enriched with chia oil (0.63%), cod liver oil (1.55%), and algal oil (1.10%). Coriander essential oil (0.038%) was added to each oil formulation. The products were monitored on days 1 and 14 of storage. The oils were pre-encapsulated in alginate beads to limit oxidative processes and preserve sensory properties. Yogurt samples were evaluated for oxidative stability, fatty acid composition, microbiological parameters, physicochemical properties, textural and sensory characteristics. Titratable acidity, pH, water-holding capacity, antioxidant activity, and microbiological parameters were not significantly affected by the incorporation of encapsulated oils. In contrast, significant differences were observed in texture and sensory attributes among the enriched variants. The chia oil sample exhibited the highest oxidative stability, followed by the algal oil yogurt, whereas the lowest stability was observed in the cod liver oil variant; however, all products remained within acceptable oxidation limits up to day 14. Approximately 350 g, 260 g, and 120 g of yogurt enriched with chia, cod liver, and algal oil, respectively, were required to meet the recommended daily omega-3 intake. The developed products demonstrated potential as dairy foods enriched with omega-3 fatty acids, with improved nutritional value.

Honey authenticity control remains analytically challenging due to the complexity of its matrix and the increasing sophistication of adulteration practices. While chromatographic, spectrometric, and isotopic methods provide high confirmatory accuracy, their routine application is constrained by cost, time, and infrastructure requirements. In this context, fluorescence spectroscopy has emerged as a rapid, non-destructive, and cost-efficient screening approach capable of capturing subtle matrix-level compositional variations. This review critically evaluates the application of steady-state and excitation–emission matrix (EEM) fluorescence in honey quality and authenticity assessment. Fluorescence is positioned within tiered analytical frameworks as a first-line or intermediate screening tool preceding confirmatory chromatographic or NMR-based analyses. Emphasis is placed on intrinsic fluorophore domains, excitation–emission measurement strategies, and chemometric interpretation, including multiway analysis and supervised classification models. Recent developments in portable LED-based systems, laser-induced fluorescence, nanoparticle-based probes, and data-fusion strategies are discussed alongside key limitations related to matrix effects, spectral overlap, reproducibility, and model transferability. The review provides a structured framework for the strategic integration of fluorescence spectroscopy into contemporary honey authentication workflows.

Purpose. This review aims to present recent data from contemporary scientific literature on the anti-neuroinflammatory effects of selected herbs from the Lamiaceae family. Material and methods. A literature search was conducted to obtain current information on the role of phenolic compounds from Lamiaceae species in neuroinflammation. The Lamiaceae family, widely represented across Europe by genera such as Salvia, Mentha, Melissa, Origanum, Ocimum, Thymus, and Satureja, is a rich source of bioactive phenolic compounds with antioxidant, anti-inflammatory, and emerging neuroprotective potential. Results. Species belonging to the Lamiaceae family, including rosemary, sage, mint, thyme, oregano, and others, are rich in phenolic compounds, particularly phenolic acids and flavonoids. These herbs demonstrate promising anti-neuroinflammatory and neuroprotective properties, largely attributed to their phenolic content. Conclusion. Phenolic compounds from Lamiaceae plants modulate key neuroinflammatory pathways by suppressing microglial activation, downregulating pro-inflammatory mediators, and activating antioxidant defences. Through these mechanisms, they mitigate oxidative stress and promote neuronal survival, thereby exerting protective effects in experimental models of neuroinflammation and neurodegenerative disorders. Thus, phenolic compounds from Lamiaceae species represent promising multifunctional agents for targeting neuroinflammation and potentially slowing the progression of neurodegenerative diseases.

The poor intestinal permeability of sodium alendronate (NaALD), a BCS Class III drug, severely limits its oral bioavailability. The self-double-emulsifying drug delivery system (SDEDDS) formulation containing phosphatidylcholine (PLG 1.1) demonstrated its ability to form micro- and nano-emulsions under gastric and intestinal conditions, as well as superior permeation across a biomimetic membrane in vitro , achieving 88% drug transfer. The self-emulsification time of both formulations was consistent with the average gastric transit time. In a rat model, the PLG 1.1 system significantly enhanced bioavailability, resulting in a 1.8-fold increase in cumulative urinary excretion of NaALD over 48 hours compared to a reference. In contrast, the other formulation, which did not contain phosphatidylcholine (Smix1 3.0), showed no improvement. It was concluded that the phosphatidylcholine-based SDEDDS represents a viable strategy to overcome the permeability barrier and improve the oral absorption of alendronate.

Chlorella vulgaris is a microalga with well-established nutritional, antioxidant, anti-inflammatory, and antibacterial potential. The current study aimed to explore the green synthesis of silver nanoparticles (AgNPs) using the ethanolic extract of C. vulgaris and to assess how nanoparticle formation affects the chemical composition, antimicrobial potential, antioxidant capacity, and spasmolytic activity of the extract, building on earlier evidence for its modulatory effects on gastrointestinal smooth muscle. Even though AgNPs from Chlorella have been obtained previously, to the best of our knowledge, their spasmolytic activity has not been evaluated. To assess their properties and stability, ATR-FTIR, TEM images, XRD, DLS, and zeta potential were used. The obtained AgNPs were mostly spherical (with a diameter between 10 and 50 nm) and showed good colloidal stability. The synthesis of AgNPs resulted in significant changes in lipid composition, pigment content, and fatty acid profiles, including a decrease in total chlorophylls and an increase in mono- and polyunsaturated fatty acids. The biosynthesized AgNPs showed moderate to strong antibacterial activity against a variety of Gram-positive and Gram-negative bacteria, yeasts, and fungi. The most pronounced inhibitory effect was observed against A. niger and P. chrysogenum. In ex vivo organ bath experiments, AgNPs modulated the contractile activity and the spasmolytic profile of isolated rat gastric smooth muscle compared with C. vulgaris extract. These results demonstrate that green-synthesized AgNPs present systems with altered smooth muscle activity and improved antibacterial qualities, underscoring their potential for use in functional foods, nutraceuticals, and gastrointestinal therapeutics.