Volume 26, No. 1 (2025)
Articles
PIGMENTED YEASTS AS SOURCES OF SUBSTANCES WITH ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY
NATALIA CHISELIȚA(*), OLEG CHISELIȚA, ELENA TOFAN, MARINA DANILIȘ, ANA ROZLOVAN
The purpose of this work was to evaluate the biochemical, antioxidant and antimicrobial potential of eight strains of pigmented yeasts from the genus Rhodotorula and Sporobolomyces. Biomass productivity, protein, carbohydrate, carotenoid contents, total antioxidant activity, catalase-type enzymes and antifungal activity of the strains cultivated on the YPD nutrient medium under identical conditions were determined. The obtained results allow us to conclude that the biomass of pigmented yeasts, especially Rhodotorula gracilis, is an excellent source of proteins of 64.53±9.10 - 74.93±7.41 % d.w. and carotenoids of 190.1±19.1 - 293.23±24.84 µg·g-1, the content of which varies depending on the strain. At the same time, of the eight studied strains, the S. pararoseus CNMN-Ys-01 showed maximum carotenoid synthesis potential of 341.26±51.29 µg·g-1. The studied yeast strains possess high antioxidant activity up to 85.48±3.93 % of inhibition and of CAT-type enzymes at the level of 91.87±8.18 - 738.0±81.88 mmol·min-1·mg-1 protein. The antimicrobial test established that the studied yeast strains showed antagonism towards some strains of phytopathogenic fungi. Thus, pigmented yeasts present a valuable source of biologically active substances with antioxidant, enzymatic and antimicrobial effects with enormous potential for use in agriculture, animal husbandry, veterinary medicine, the cosmetic industry, etc.
SYNTHESIS, CHARACTERIZATION AND EVALUATION OF NOVEL QUINOLINE MOLECULES AS ANTIBACTERIAL AGENTS
SEEMA KHAN, NARENDRA K. SINGH, SHANKAR SINGH, AVINASH K. KONDALKAR(*)
The objective of the present investigation was to synthesize novel quinoline derivatives for antibacterial activity. Five compounds SK1-5 were synthesized and these compounds were tested yield (%), solubility, retention factor (Rf) and melting point (°C). The compounds were evaluated for antibacterial activity using zone of inhibition method at four different concentrations. The products were insoluble in water, methanol and DMSO while they were soluble in chloroform and were obtained in 67 - 76 % yield. The antibacterial action against both gram-positive and gram-negative bacteria was exhibited by the compounds. The compounds were found to be possessing better inhibitory action against the gram-negative bacteria in comparison to gram positive bacteria. The zone of inhibition exhibited by SK3 was highest among all compound and it was equally effective in both gram-negative and positive bacteria.
THE EFFECT OF AMARANTH SEEDS ON THE CHEMICAL, MICROBIOLOGICAL AND SENSORY QUALITY OF YOGURT
GJORE NAKOV(1*), NADYA NINOVA-NIKOLOVA(2), NASTIA IVANOVA(1), VIOLETA RAYKOVA(1), BILJANA TRAJKOVSKA(3)
The objective of this study was to investigate the chemical, microbiological, and sensory characteristics of yogurt enriched with amaranth seeds, stored at a temperature range of 5 ± 1 °C for 21 days. The quantity of amaranth incorporated into the yogurt was 5 % and 10 %. The changes were regularly observed and recorded every 7 days. Statistically significant results (p ≤ 0.05) show that as storage time increases, pH values decrease, and acidity increases. The fat content remains consistent regardless of the amount of amaranth stored. The inclusion of amaranth seeds in yogurt resulted in a statistically significant increase (p ≤ 0.05) in the protein content of the final product. All yogurt samples demonstrate the absence of Enterobacteriaceae, yeast and molds, Coagulase-positive staphylococci, Salmonella spp. and Listeria monocytogenes after 21 days of storage, ensuring product safety. Sensory quality was evaluated based on color, taste, aftertaste, texture, and overall acceptability at 1, 7, 14, and 21 days. The results indicate that the sensory quality of yogurt decreases as the concentration of amaranth seeds increases. Except for the control sample (without amaranth seeds), yogurt with 5 % amaranth seeds exhibited superior sensory quality compared to yogurt with 10 % amaranth seeds.
COMPUTATIONAL SOLUTIONS FOR DETERMINING THE SPATIAL-TEMPORAL EVOLUTION OF POLLUTANTS ON THE PRUT RIVER SECTOR IN GIURGIULEȘTI LOCALITY
GALINA MARUSIC(1), NINA SAVA(2*), RODICA BRANIȘTE(1), VIOREL CĂRBUNE(1), VICTOR ABABII(1)
This work represents a research in the field of modeling the spatial-temporal evolution of pollutants. The Navier-Stokes equations were applied for the mathematical formulation of the spatial-temporal evolution of pollutants in river ecosystems, which are fundamental in fluid mechanics and describe the motion of fluids under different conditions. The SMS (Surface-water Modeling System) environment was used to determine the spatial-temporal evolution of pollutants, which is a software developed for modeling and simulation of surface water flows. An important evolution was the use of the application of 2/3D hydrodynamic models that simulate water flow in one plane, taking into account two spatial dimensions (longitude and latitude). The pollutant behavior simulation approach will contribute to the assessment and forecasting of potential natural catastrophes of riverine aquatic ecosystems. This research aims to explore the computational methods and technologies and comes up with some solutions that can be used to analyze the distribution and evolution of pollutants on the Prut river sector in Giurgiulești locality. A comparative analysis of several commercial Software (ANSYS Fluent, COMSOL Multiphysics, STAR-CCM+) and Open-Source Software (OpenFOAM, SU2, Gerris) was carried out, and the advantages of each software in the process of numerical simulation of the spatial-temporal evolution of pollutants were found.
DYNAMIC STUDY BEHAVIOR OF THE FLUIDIZED BINARY MIXTURE BED WITH BENTONITE PARTICLES
GABRIELA MUNTIANU(1), ILEANA-DENISA NISTOR(1*), ANA-MARIA GEORGESCU(1), ANA-MARIA ROȘU(1), DIANA-CARMEN MIRILĂ(2, 3), ALINA MONICA MAREȘ(4), COSMIN VALERIU JINESCU(5*)
This study presents experimental data on the behavior of gas-solid systems in classical fluidization of simple particles and binary mixtures. Sodium and calcium bentonite particles with different physical properties were used to determine dynamic parameters. The use of bentonite particles is often recommended because they are easy to manipulate and have high specific surface areas for gas-solid contact. The study examines the influence of average particle diameter ( ) and bed height (H0) on bed porosity (ε0), pressure drop (ΔP), and minimum fluidization velocity (Umf). Bentonite particles in a fluidized bed belong to Groups B and D according to Geldart's classification. The binary mixture particles have the same diameter but different densities and are pseudo-homogeneously mixed. The minimum fluidization velocity for well-mixed particles (Umf,mix) was determined for two mixtures with 0.57 mass fraction of sodium bentonite and bed ratios (H0/D) close to 2. Experimental values for minimum pressure drop (ΔPmin), minimum fluidization velocity (Umf), and minimum fluidization velocity for the mixture were compared with theoretical values using empirical equations. Regression analysis of all experimental data provided an empirical model for Umf and Umf,mix. The study aims to achieve better dynamic conditions for efficient and effective use of binary mixtures in future adsorption processes.
FLAXSEED - ARROWROOT GEL AS AN EGG REPLACER IN MUFFINS: NUTRITIONAL, PHYSICOCHEMICAL AND SENSORY PROPERTIES
ZHIVKA T. GORANOVA(1*), HRISTO R. KALAYDZHIEV(2), JESÚS BLESA(3), TODORKA V. PETROVA(1), ANKA TRAJKOVSKA PETKOSKA(4,5)
Flaxseeds and arrowroot starch are considered healthy ingredients for the development of functional foods due to their high nutritional and biological value. The egg substitute in the form of flaxseed and arrowroot gel is prepared in a ratio of 1:1:10 (flaxseed:arrowroot:water). This egg substitute was used in muffins at the levels of 0 %, 50 %, and 100 %. All samples were analyzed for physical-chemical, nutritional, and sensory properties. The results showed that flaxseed and arrowroot gel significantly improved the fiber and fat content, but the protein and carbohydrate content was reduced compared to egg muffins. Antioxidant activity increased in eggless muffins than in control. The caloric value was found to be reduced, resulting in a low-calorie product. The results of sensory characteristics show that up to 100 % replacement of eggs with plant-based gel in muffins is satisfactory in the qualitative aspect. Therefore, flaxseed and arrowroot gel can be used as an alternative to eggs and applied as a new functional ingredient in various bakery products.
CHARACTERIZATION OF CLOUDY APPLE JUICE OBTAINED FROM SIX AUTHENTIC VARIETIES FROM VALEA DÂMBOVIȚEI
DENISA MARICA(1*), MARIA LIDIA IANCU(2), MIHAELA ADRIANA TIȚA(3), OVIDIU TIȚA(3)
The cloudy apple juice obtained from 6 varieties of apples is analyzed in this study (EJ7). Organography and analytical determinations highlighted the Sirius apple variety. Using the prediction model of the values of the quality indicators, it was possible to estimate: soluble dry matter (TTS), titratable acidity (TTA), total anthocyanins content (AT), ascorbic acid content (AA) in the blend. These values are closely related to the actual ones. Thus for the blend (EJ7): TTA = 15.5 oBx, TA = 0.5 g/100mL expressed in malic acid, AT = 6.8 mg·L-1 cyanidin-3-glucoside. The content of ascorbic acid decreases compared to that of apples. By generating the linear regression equation for the correlation of relative density and kinematic viscosity values, a correlation index of 58 % was obtained. When blending cloudy juices, the influencing factors for the values of the quality indicators are: the size of the particles of the turbidity, the variety of apple and the proportion of the blend, exposure to high temperature, the action of oxygen. Blending juices obtained from different apple varieties, from the small production of an orchard is beneficial because it is possible to obtain a juice variant with superior sensory characteristics, as was also obtained in this study (EJ7 obtained a maximum score of 5 points) and with quality indicators with values corresponding to the assortment and predictive. A larger quantity of juice with constant quality characteristics is also obtained.
THE EFFECTS OF MINERALS AGGREGATES EXTRACTION ON PROTECTED BIRD SPECIES IN THE NATURA 2000 SITE FROM PRAHOVA COUNTY: NOISE POLLUTION EVALUATION
LUIZA-GEORGETA CRĂCIUNICĂ, CRISTINA ILEANA COVALIU-MIERLĂ(*), VLAD GEORGE DINU, OVIDIU GHEORGHIU, IULIANA DELEANU
This paper assesses the ambient noise produced by mineral aggregate extraction activities. The extractive industry is vital for people's livelihoods and significantly contributes to the economy of every state. However, it also presents several major challenges, including land use changes, erosion, air pollution from dust, disturbances to vegetation, and noise pollution, among others. This study specifically examined two areas in Prahova County, where mineral aggregate extraction takes place through dredging operations along the minor channels of the Prahova River. This region is part of the Natura 2000 network, particularly the ROSPA0152 Ialomița Corridor, which is designated for the protection of bird species. In this research the presence of characteristic bird species was evaluated and the temporary effects of noise generated by the extraction activities were observed.
THE INFLUENCE OF INDIGENOUS YEAST STRAINS ON THE CONCENTRATION OF PHENOLIC SUBSTANCES AND COLOR INDICES IN RED WINE CABERNET SAUVIGNON
OLGA SOLDATENCO(*), NICOLAE TARAN, VICTORIA ADAJUC
This study investigates the influence of nine indigenous yeast strains on the quality of dry red wines, focusing specifically on their effect on the concentration of phenolic compounds and color indices from 2 winemaking centers in Moldova. Yeast strains isolated '21-C-S-120-P-2', '24-R-NNP-2', '29-R-N-120-P-4', and '30-R-N-120-P-5', were selected in the Purcari winemaking center and '27 -MTr-4', '32-M100Tr-1', '35-M100Tr-4', 41-C-S60Tr-2', and '43-C-S60Tr-4' were selected in the Trifeshti winemaking center significantly used in the fermentation of 'Cabernet-Sauvignon' grape must improve phenolic extraction. The results of the study showed that 2 strains significantly improved the content of phenolic compounds, in the case of strain '30-R-N-120-P-5' a concentration of 1542 mg·L-1 of total phenolic compounds and 298 mg·L-1 of anthocyanins was obtained, while strain '41-C-S60Tr-2' produced 1520 mg·L-1 phenolic compounds and 302 mg·L-1 of anthocyanins. Wines fermented with these indigenous strains were compared to a commercial control strain, 'Oenoferm Be-Red'. Both strains showed a significant increase in total phenolic compounds and color intensity, with strain '41-C-S60Tr-2' reaching the highest color intensity at 15.4. Research highlights the potential of indigenous yeast strains to increase the concentration of phenolic compounds and improve the color indices of dry red wines.