The aim of this study was to evaluate the bioactive compounds and antioxidant activity of lemon balm (Melissa officinalis L.) grown under two farming systems (conventional vs. organic farming). From the content of photosynthetic pigments, total phenolics, and total flavonoids, as well as individual phenolic acids and flavonoids, the antioxidant potential was evaluated in 95% and 50% ethanol extracts. Moreover, GC-MS analysis of lemon balm essential oils was used to reveal the detailed composition. Forty-three compounds were detected in the essential oil from organic farming lemon balm, representing 99.70% of the total content. Among these, several compounds, such as α-pinene, n-octan-3-ol, bergamal, trans-rose oxide, dihydro-linalool, cis-isocitral, and trans-anethole, were found exclusively in the organic essential oil. In comparison, thirty-six compounds were detected in the essential oil from conventionally grown plants, representing 99.80% of the total content. The organically grown lemon balm demonstrated higher values of phenolics, flavonoids and antioxidant activity in comparison to the conventional ones. The levels of natural pigment were more than twice as high in the conventionally grown samples. Moreover, the 50% ethanol extracts contained 1.5 to 2 times more phenolic compounds with the highest antioxidant potential by the CUPRAC method. A positive linear correlation (r2 = 0.98) was found between total phenolics and electron transfer-based antioxidant methods. Therefore, the organic farming led to the production of lemon balm with more secondary metabolites, such as phenolic acids and flavonoids, with higher antioxidant activity.
Xylaria karsticola NBIMCC 9097 is a recently described and rare fungicolous species originating from Bulgaria. Understanding its growth behavior and bioactive potential is essential for evaluating its biotechnological and pharmaceutical relevance. In the presented study, we model the in vitro growth kinetics of X. karsticola mycelium under submerged cultivation and assess its antimicrobial activity. Optimization of MCM and MYB media markedly increased biomass yields to 20.11 and 23.25 g/dm3, respectively, compared with non-optimized media (9.9 ± 0.21 and 10.8 ± 0.28 g/dm3). The maximum specific growth rate was higher in the MCM (0.803 ± 0.004 h-1) in comparison with the MYB medium (0.711 ± 0.003 h-1); however, the MYB medium supported greater biomass accumulation and more efficient substrate utilization, reflected by a higher utilization coefficient (0.9900 ± 0.001 versus 0.9644 ± 0.005). The antimicrobial activity was evaluated using agar disk diffusion and minimum inhibitory concentration assays against Gram-positive and Gram-negative bacteria and yeasts. Hexane and ethyl acetate extracts were most effective against Pseudomonas aeruginosa ATCC 9027 (MIC 0.067 and 0.059 mg/cm3), while notable anti-yeast activity was observed, particularly against Wickerhamomyces anomalus, Saccharomycodes ludwigii, and Pichia membranifaciens. The lowest MIC (0.02 mg/cm3) was recorded for the water biomass extract against S. ludwigii indicating potent antimicrobial activity against the tested microorganism. These findings identify X. karsticola as a potential source of antimicrobial metabolites and provide a strong motivation for comprehensive metabolomic profiling and systematic optimization of its cultivation.
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.
Wafers are popular low-moisture confectionery products, typically composed of thin baked sheets and sweet fillings, which provide extended shelf life and distinctive texture. This study investigates the influence of different tahini-based fillings on the sensory and physicochemical properties of wafers. Tahini, a nutrient-dense paste from roasted oil-bearing seeds, offers high dry matter content (98.42–99.53%) and functional health benefits, making it a suitable long-life ingredient. Four tahini types: sesame, peanut, sunflower and hazelnut, were incorporated into fillings, and their hygroscopic behavior at φ = 68% relative humidity was assessed. Sensory analysis revealed that tahini fillings reduced wafer crispiness across all variants, likely due to moisture migration into wafer sheets. Sweetness perception varied, with sesame tahini wafers rated sweetest and sunflower tahini wafers least sweet, while hazelnut and peanut variants showed no significant difference. Hedonic evaluation ranked hazelnut tahini wafers highest for appearance and texture, and peanut tahini wafers highest for aroma and taste, whereas sesame tahini wafers received the lowest ratings overall. The results highlight that tahini type significantly influences wafer hygroscopicity, sensory attributes, and consumer acceptability.
Heated tobacco products (HTPs) are marketed as alternatives to conventional cigarettes and as products with potentially reduced harm. Despite the growing consumption of HTPs worldwide, their chemical composition and physical properties remain insufficiently explored. This study aims to examine the design and the physical and chemical characteristics of HTPs sold on the Bulgarian market. The physical dimensions and weight of the sticks and their structural components were determined, as well as the main chemical indicators of the incorporated tobacco material and the aerosol produced, respectively - ash, total reducing sugars, nicotine, cellulose; total and dry particulate matter, etc. The results indicate high cellulose levels in the tobacco material (13.10–18.39%) and relatively higher total particulate matter (26.63–39.86 mg/stick) compared to conventional cigarettes. The obtained results expand the knowledge about the structure and composition of HTPs and contribute to a deeper understanding of their physical and chemical characteristics.
