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Chemical Characterization and Antibacterial Activity of Essential Oil of Medicinal Plants from Eastern Serbia
No full textThe objective of this study was to evaluate wild growing Satureja kitaibelii, Thymus serpyllum, Origanum vulgare, Achillea millefolium and Achillea clypeolata with respect to their essential oil (EO) content, composition and antimicrobial activity. The five species were collected at Mt. Rtanj and the village of Sesalac, Eastern Serbia. The main EO constituents of Lamiaceae plants were p-cymene (24.4%), geraniol (63.4%) and germacrene D (21.5%) in Satureja kitaibelii, Thymus serpyllum and Origanum vulgare ssp. vulgare, respectively. A. millefolium EO had multiple constituents with major ones being camphor (9.8%), caryophyllene oxide (6.5%), terpinen-4-ol (6.3%) and 1,8-cineole (5.6%), while the main EO constituents of A. clypeolata were 1,8-cineole (45.1%) and camphor (18.2%). Antimicrobial testing of the EO showed that Staphylococcus aureus (Gram-positive) was more sensitive to all of the tested EOs than Escherichia coli (Gram-negative). S. kitaibelii EO showed the highest antimicrobial activity against both tested bacterial strains. This is the first study to characterize the EO composition and antimicrobial activity of these five medicinal species from Eastern Serbia in comparison with comprehensive literature data. The results can be utilized by the perfumery, cosmetics, food and pharmaceutical industries, but also for healing purposes in self-medication
Supercritical extracts of wild thyme (Thymus serpyllum L.) by-product as natural antioxidants in ground pork patties
No full textThe effects of wild thyme by-products (Thymus serpyllum L.) from supercritical fluid extraction SFE1 (100 bar and 40 degrees C) and SFE2 (350 bar and 50 degrees C) on the quality of ground pork patties evaluated by pH, CIE-color, lipid (TBARS test) and protein oxidation (thiol group content) and microbiological profile. SFE extracts were added to ground pork patties as: 0.075 mu L/g of SFE1 (T1), 0.150 mu L/g of SFE1 (T2), 0.075 mu L/g of SFE2 (T3), 0.150 mu L/g of SFE2 (T4), while SFEs (T5) was control without any extracts. SFE1 and SFE2 were protective against color degradation. Moreover, the addition of SFE1 and SFE2 significantly reduced lipid and protein oxidation in the patties (p LT = 0.05). Furthermore, lower concentration of SFE2 reduced total plate count to LT 6 log cfu/g after 3 days of storage. Obtained results indicated that SFEs of wild thyme by-product are useful as natural antioxidants and antimicrobial agents in meat processing
Isopiestic determination of the osmotic and activity coefficients of {yK(2)HPO(4) + (1-y)KH2PO4}(aq) at T=298.15 K
No full textIsopiestic measurements have been made at 55 compositions of the {yK(2)HPO(4) + (1 - y)KH2PO4}(aq) system at T = (298.15 +/- 0.01) K, 11 for each of the limiting binary solutions and 33 for mixture compositions at K2HPO4 stoichiometric ionic strength fractions y = (0.23330, 0.47671, and 0.73177), using KCl(aq) as the reference standard. Model parameters for the binary subsystems were evaluated at this temperature for an extended form of Pitzer's ion-interaction model and also for the Clegg, Pitzer and Brimblecombe model based on the mole-fraction-composition scale, using the present isopiestic results along with critically-assessed osmotic coefficients for both of these aqueous electrolytes as extracted from the published literature. The thermodynamic models for KH2PO4(aq) extend to slightly above the saturated solution molality at T = (298.15 +/- 0.01) K, whereas those for K2HPO4(aq) extend to m = 9.7429 mol.kg(-1), which is the molality of the saturated solution, also at T = (298.15 +/- 0.01) K. These results yield the CODATA-compatible standard Gibbs energy of formation Delta(f)G(m)(o)(K2HPO4 center dot 3H(2)O; cr; 298.15 K) = -(2367.70 +/- 1.60) kJ.mol(-1). The 33 osmotic coefficients for the ternary mixtures were likewise represented with these models, using both the usual Pitzer mixing terms and also Scatchard's neutral-electrolyte model mixing terms for the extended ion-interaction model. Two mixing parameters are needed for each of the three models for {yK(2)HPO(4) + (1 - y)KH2PO4}(aq), and both of these ion-interaction models give similar high-quality representations of the experimental results. However, the Clegg, Pitzer and Brimblecombe model had more difficulty in representing the osmotic coefficients of K2HPO4(aq), especially below 3 mol.kg(-1), and consequently the corresponding mixture model with two mixing parameters is slightly less accurate for representing the osmotic coefficients. The maximum difference in calculated values of the mean molality-based activity coefficients for the two recommended extended Pitzer models with the different types of mixing terms are 0.0061 for the trace activity coefficient of K2HPO4(aq) in KH2PO4(aq) but with much better agreement at most mixture compositions
Preliminary Survey of Alternaria Toxins Reduction during Fermentation of Whole Wheat Dough
No full textThe aim of this study was to investigate the fate of the most common Alternaria toxins found in wheat tenuazonic acid (TeA), alternariol (AOH), and alternariol monomethyl ether (AME) during sourdough processing. For this purpose, spiked whole wheat flour, 3% sourdough starter, 0.5% of baker's yeast, and 105% of water calculated on flour weight as a base were used as raw materials. Spiked whole wheat dough was fermented for 4 h, 8 h, 12 h, 24 h, and 48 h at 25 degrees C, and at each point the fermented dough samples were taken, frozen, lyophilized, grounded, and stored until further analysis. To study the effect of sourdough processing on TeA, AOH and AME content, the validated method of high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for these mycotoxins was used. Mathematical models of Alternaria toxins reduction were developed in the form of Four Parameter Logistic Regression function. The maximum reduction of TeA, AOH, and AME levels was archived at 48 h of dough fermentation at 25 degrees C compared with dough after kneading (0 h). Under these conditions, a reduction of the toxin levels of 60.3 %, 41.5%, and 24.1% was observed for TeA, AOH, and AME, respectively
Prediction of the GC-MS retention time for terpenoids detected in sage (Salvia officinalis L.) essential oil using QSRR approach
No full textThis work aimed to obtain a validated model for prediction of retention time of terpenoids isolated from sage herbal dust using supercritical fluid extraction. In total 32 experimentally obtained retention time of terpenes, which were separated and detected by GC-MS were further used to build a prediction model. The quantitative structure-retention relationship was employed to predict the retention time of essential oil compounds obtained in GC-MS analysis, using six molecular descriptors selected by a genetic algorithm. The selected descriptors were used as inputs of an artificial neural network, to build a retention time predictive quantitative structure-retention relationship model. The coefficient of determination for training cycle was 0.837, indicating that this model could be used for prediction of retention time values for essential oil compounds in sage herbal dust extracts obtained by supercritical fluid extraction due to low prediction error and moderately high r(2). Results suggested that a 2D autocorrelation descriptor AATS0v was the most influential parameter with an approximately relative importance of 25.1 %
Functionality and Storability of Cookies Fortified at the Industrial Scale with up to 75% of Apple Pomace Flour Produced by Dehydration
No full textApple pomace flour (APF) with high content of dietary fibers (DF), total polyphenolics (TPCs) and flavonoids (TFCs) was produced at the industrial scale. Bulk and tapped density, swelling, water and oil holding capacity, solubility and hydration density of fine and coarse APF with average particle size 0.16 and 0.50 mm were compared. The effect of wheat flour substitution with 25%, 50% and 75% of fine and coarse APF was studied upon cookies production at the industrial scale and after one year of storage. Coarse APF performed better in respect to sensorial properties, content and retention of dietary compounds and antioxidant (AO) activity. The cookies with optimal share of coarse APF (50%) contained 21 g/100 g of DF and several times higher TPC, TFC as well as AO activity than control cookies, retained well health promoting compounds and maintained an intensely fruity aroma and crispy texture. They were acceptable for consumers according to the hedonic test
Hydrothermal synthesis of Mn2+ doped titanate nanotubes: Investigation of their structure and room temperature ferromagnetic behavior
No full textHydrothermal synthesis of Mn2+ doped titanate nanotubes (TNTs), which exhibited room temperature ferromagnetism (RTFM), is reported. Dispersions of 1 and 5 at.% Mn2+ doped anatase TiO2 nanocrystals were used as precursors. Size and shape of Mn2+ doped TNTs and precursor nanocrystals were studied by transmission electron microscopy (TEM). The relatively uniform size distribution of transverse dimension of nanotubes of about 10 nm was observed while their lengths varied up to few hundred nanometers. The X-Ray Diffraction (XRD) analysis and Raman spectroscopy of resultant powder confirmed the hydrogen dititanate (H2Ti2O5 x H2O) crystal phase of Mn2+ doped TNTs with the presence of small amount of sodium titanates. Electron paramagnetic resonance (EPR) experiments were performed to probe the local atomic and electronic structure of Mn in the nanotubes. Room temperature ferromagnetic ordering with saturation magnetic moment (Ms) in the range of 0.6–1.5 μB per Mn atom was observed
Predictive model for municipal waste generation using artificial neural networks-Case study City of Zagreb, Croatia
No full textThe European Union's environmental legislation related to environmental protection, already implemented in the national legislation of the Republic of Croatia, aims to introduce a system of integrated and sustainable waste management. Within such a system, it is of utmost importance to have a better estimate of the amount of municipal waste generated, which directly influences future planning in the waste management sector. The aim of this research was to develop and optimize models for the estimation of generated municipal waste by application of methodology using neural network models, and taking into account the socio-economic impact as well as the inputs regarding the actual waste management trends. In this paper, an artificial neural network models were used to predict the municipal waste generation in Zagreb, Croatia. The standardized socio-economic and waste management variables were chosen to encompass 2013 to 2016 period. Moreover, the test prediction of the observed data was performed for 2017. Developed models sufficiently predicted the quantities of different municipal waste fractions and in that sense can contribute to better planning of upcoming waste management systems that will be sustainable and in order to meet the European Union commitments
Antioxidant Capacity of Nettle Leaves During Osmotic Treatment
No full textOsmotic treatment (OT) of nettle leaves was assessed in various osmotic solutions (sugar beet molasses - SBM and ternary aqueous solution - TAS), at temperatures of 20, 35 and 50 degrees C, under the atmospheric pressure. The influence of the kind of utilized osmotic solution, process temperature and osmotic time on the antioxidant activity (AOC), expressed with the spectrophotometric assays (ABTS, FRAP and DPPH), as well as two direct current polarographic assays, Hydroxo Perhydroxo Mercury (ii) complex assay, based on the decrease of anodic current and assay based on the decrease of a cathodic current of Hg (II) reduction. For determination of the total phenolic content Folin-Ciocalteu assay was used. The Relative Antioxidant Capacity Index (RACI), obtained by setting equal weight for every involved assay was applied in order to get an extensive comparison among analyzed samples and between the used assays. Based on these results, after the OT of nettle leaves in TAS, the AOC decreased, while the OT in SBM increased AOC values. The phenolic antioxidant coefficients (PAC), calculated as the ratio between particular AO capacity and TPC, were used to achieve a more comprehensive comparison between analysed samples, as well as applied assays. The results of RACI evaluation revealed that the most favorable osmotic treatment is the one performed for 5h at 35 degrees C
Corrosion behaviour of ZnTa2O6 pseudo-binary oxide, zinc meso-tetra(4-pyridyl) porphyrin (ZnTPyP) and hybrid ZnTa2O6/ZnTPyP layers deposited by PLD
No full textThe anticorrosive properties of single and sandwich layers obtained by pulsed laser deposition (PLD) of the pseudo-binary oxide ZnTa2O6 and zinc meso-tetra(4-pyridyl) porphyrin (ZnTPyP) on steel were investigated. Intercalated thin layers made by PLD technique from the pseudo-binary oxide ZnTa2O6 and zinc meso-tetra(4-pyridyl) porphyrin (ZnTPyP) are expected to self-assemble into ordered nanoparticles and to exhibit uniformity and adherence, offering novel anticorrosive properties. The corrosion tests were performed in solution 0.1 mol l(-1) NaCl. The best corrosion resistance was exhibited by the steel electrode modified with ZnTPyP/ZnTa2O6 deposited layers, i.e. 66.64% inhibition efficiency