Lato Pezo

Antioxidant activity of propolis extracts from Serbia: A polarographic approach

Antioxidant activity (AO) of commercial propolis extracts (PEs), available on Serbian market, was determined by direct current (DC) polarography. Polarographic anodic current of 5.0 mmol L(-1) alkaline solution of H2O2 was recorded at potentials of mercury dissolution. Decrease of the current was plotted against the volume of gradually added PEs. The volume of PE causing 20% current decrease was determined from the linear part of the plot. Antioxidant activity was expressed in H2O2 equivalent (HPEq), representing the volume of PE that corresponds to 1.0 mmol L(-1) H2O2 decrease. Resulting HPEq ranged between 1.71±0.11 and 8.00±0.18 μL. Range of 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity was from 0.093±0.004% to 0.346±0.006%. Total phenolic content (TCP) of PE with superior AO activity was 5.31±0.05% g GAE, while the extract with the lowest activity contained 1.45±0.02% g GAE. Antioxidant activity, determined by polarographic method, was correlated with DPPH scavenging activity (R2=0.991) and TCP (R2=0.985). Validity of obtained results was further confirmed using ANOVA and post hoc Tukey HSD test.

Removal of mineral oil and wastewater pollutants using hard coal.

This study investigates the use of hard coal as an adsorbent for removal of mineral oil from wastewater. In order to determine the efficiency of hard coal as an adsorbent of mineral oil, process parameters such as sorption capacity (in static and dynamic conditions), temperature, pH, contact time, flow rate, and chemical pretreatment were evaluated in a series of batch and continuous flow experiments. There were significant differences in the mineral oil removal for various pH values examined. The adsorption of mineral oil increased as pH values diverged from 7 (neutral). At lower temperatures, the adsorption was notably higher. The wastewater flow rate was adjusted to achieve optimal water purification. Equilibrium was reached after 10 h in static conditions. At that time, more than 99% of mineral oil had been removed. At the beginning of the filtering process, the adsorption rate increased rapidly, only to show a minor decrease afterwards. Equilibrium data were fitted to Freundlich models to determine the water-hard coal partitioning coefficient. Physical adsorption caused by properties of the compounds was the predominant mechanism in the removal process.

Can the origin of some metals in the seagrass Posidonia oceanica be determined by the indexes of metals pollutions

To assess metal pollution, Fe, Mn, Cu, Zn, Pb, Ni, Co, As, Cd, and Hg contents in samples of the seagrass Posidonia oceanica and surface sediment, collected at eight locations along the Montenegrin coast, were determined. The metal pollution index (MPI) and metal enrichment factor (EF) were then calculated. MPI and EF were lower in sediment than in P. oceanica at the same locations. This was very evident for EF values of Hg and Cd. Based on the Pearson’s correlations and EF values, it was possible to conclude that the last two metals’ content in the seagrass did not originate from the crustal sources or natural weathering processes.

Characterization of the liposoluble fraction of common wheat (Triticum aestivum) and spelt (T. aestivum ssp. spelta) flours using multivariate analysis.

BACKGROUND In the present paper, a special method for derivatization of liposoluble extract of common wheat and spelt flours was employed which enables simultaneous detection of fatty acid and non-saponifiable lipid fractions. RESULTS Gas chromatographic-mass spectrometric analytical data for both fractions were separately analyzed by multivariate statistical techniques to model classes of different common wheat and spelt cultivars. Cluster analysis was used, and the results obtained revealed that better discrimination of samples was achieved by analyzing the peak area after 16 min retention time (non-saponifiable lipids), rather than commonly used peak area between 12 and 16 min (fatty acid fraction), due to more distinctive positions of points in factor space, even though the distances between points for fatty acid fraction (12-16 min) were greater. Similar results were obtained by principal components analysis, where all wheat points almost coincided whereas spelt showed good discrimination. CONCLUSION Comparison of chromatogram areas for non-saponifiable lipid fraction between common and spelt wheat showed a statistically high difference and hence has a potential for use in authenticity control.

Aflatoxins contamination of maize in Serbia: The impact of weather conditions in 2015

ABSTRACT In recent years climate changes recorded in temperate regions of Europe have led to aflatoxin (AF) contamination of maize. Thus, the aim of this study was to investigate the influence of weather conditions on levels of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) in 180 maize samples collected from the main maize-growing regions (Western Bačka, North Banat, South Banat and Central Serbia) in Serbia after harvest in 2015. The concentrations of AFs were determined by a validated HPLC method with post-column derivatisation and fluorescence detection (HPLC-FLD). The presence of AFB1, AFB2, AFG1 and AFG2 was detected in 57.2%, 13.9%, 5.6% and 2.8% of maize samples in the concentration ranges of 1.3–88.8 µg kg–1, 0.60–2.8 µg kg–1, 1.8–28.5 µg kg–1 and 2.1–7.5 µg kg–1 respectively. The recorded smaller amount of precipitation and especially higher air temperatures during the summer of 2015 were favourable for AF production, which resulted in 32.2% and 21.1% of samples being unsuitable for human consumption, since AFB1 and the sum of AFs concentrations were above 5.0 and 10.0 µg kg–1 respectively. Furthermore, the findings in this study indicate that the microclimate conditions in the investigated regions had a great influence on the contamination frequency of maize with AFs. The highest percentage of samples unsuitable for human consumption, considering both AFB1 and total AFs content were 72.5% and 51.5% respectively from Central Serbia, whilst the lowest percentages of 15.6% and 6.2% respectively were found in Western Bačka. These findings confirmed that maize should be continuously monitored in order to protect human and animal health from the harmful effects caused by AFs contamination.

Possibility of Alternaria toxins reduction by extrusion processing of whole wheat flour.

This study represents the first report about possibility of reduction of Alternaria toxins in wheat using the extrusion process. Effects of extrusion processing parameters - moisture content (w=16, 20, 24g/100g), feeding rate (q=15, 20, 25kg/h), and screw speed (v=300, 390, 480rpm), on reduction rate of tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME), in whole wheat flour were investigated. Temperature ranged between 111.1 and 160.8°C, while the absolute pressure was from 0.17 to 0.23MPa. The simultaneous influence of w and v was the most important for TeA reduction (p<0.05), while v and q were the most influential for AOH reduction (p<0.01). Level of AME reduction was mostly influenced by w and v (p<0.10). Optimal parameters for reduction of all three Alternaria toxins were as follows: w=24g/100g, q=25kg/h, v=390rpm, with a reduction of 65.6% for TeA, 87.9% for AOH and 94.5% for AME.

Elemental analysis of mussels and possible health risks arising from their consumption as a food: The case of Boka Kotorska Bay, Adriatic Sea

The present study investigated the essential and non-essential elements in cultivated and wild mussels and assessed the health risk arising from their consumption as an impact of rapid growth and intensive production of Mytilus galloprovincialis in the mussel farms of the Boka Kotorska Bay. The concentrations of macro, micro, nonessential and even the small amounts of potentially toxic elements in the cultivated and wild mussels were influenced by industry, tourism and the geohydrology of the Bay. In the case of cultivated mussels, the limiting factor, i.e., the element the elevated concentration of which restricts mussels consumption, was Zr, while in the case of wild mussels the limiting factors were Cr and As. The sites with cultivated mussels stand out as sites with the highest calculated element pollution index, the total hazard index and with higher estimated risk to the health of consumers.

Analysis of trace elements in surface sediments, mussels, seagrass and seawater along the southeastern Adriatic coast – a chemometric approach

Abstract Surface sediments, mussels, seagrass, surface and bottom seawater samples were collected from the costal area of the southeastern Adriatic Sea and analyzed in order to determine the concentration and origin of the following elements: Fe, Mn, Zn, Ni, Cu, Ni, Co, As, Cd, Cr and Hg. The complexity of the obtained data was reduced by principal component analysis (PCA) and cluster analysis (CA), methods well known and accepted for the identification of the quality of marine environments. Both PCA and CA analysis were used to discriminate groups of samples according to the similarity of their chemical composition. The results revealed good diversity between the various samples, expressed by their distinctive positions of points in factor space. PCA indicated that the first two PC components explained about 73, 48, 43, 48, and 50 % of the total variance of the data for sediments, mussels, seagrass, and surface and bottom water, respectively. The results showed good discrimination capabilities between the samples taken from different locations, and also different seasons, which was especially evident in the surface and bottom water samples. Simultaneously, PCA/CA analysis of the amounts of trace elements found in the marine organisms could explain the manner of their bioaccumulation.

Utilization of Phosphate Rock from Lisina for Direct Application: Release of Plant Nutrients in the Exchange-Fertilizer Mixtures

This study examined the possibility of direct application of phosphate rock (PR) from Lisina deposit, in a mixture with natural clinoptilolite (Cp) and clinoptilolite partially saturated with ammonium ions (NH4-Cp). Solution P concentrations of the NH4-Cp/PR mixtures were sufficient for plant growth and ranged from 0.36 to 0.82 mg L(-1). The median NH4-Cp/PR ratio and the longest proposed mixing time had the most positive impact on the P concentration. Solution Ca concentrations of the NH4-Cp/PR mixtures were between 112.5 and 700.5 mg L(-1), indicating that use of the proposed NH4-Cp/PR mixtures solves the potential lack of Ca(2+) in the solution, which is typical for substrates of similar composition. Selected artificial neural networks (ANNs) were able to predict experimental variables for a broad range of the process parameters all through assay. Manifold effects of small changes in composition of the mixtures and time on the observed concentrations of nutrients were shown using the sensitivity analysis.

Clinical Features of Ocular Sarcoidosis in Patients with Biopsy-proven Pulmonary Sarcoidosis in Serbia

ABSTRACT Purpose: To analyze clinical characteristics of ocular sarcoidosis in a group of biopsy-proven sarcoid patients treated at the single referral center for sarcoidosis in Serbia. Methods: A prospective study carried out on 88 biopsy-proven sarcoid patients between January 2012 and December 2014. All patients underwent complete ophthalmological examination. Results: Ocular sarcoidosis was present in 32 patients (36.4% of all) and included: eyelid skin lesions (2.3%); orbital inflammation (2.3%); conjunctival lesions (7.9%); anterior uveitis (2.3%); intermediate uveitis (1.1%); posterior uveitis (15.9%); panuveitis (5.7%), and neuro-ophthalmologic manifestations (9.1%). Complications included cataract (20.4%); glaucoma (5.7%); cystoid macular edema (3.4%); epiretinal membrane formation (4.5%); macular atrophy (2.3%); and choroidal neovascularization (1.1%). Binocular visual impairment was present in one patient (1.1%), due to complications of posterior uveitis (macular scars). Conclusions: Patients in Serbia demonstrated ocular sarcoidosis as the first most common site of extrapulmonary sarcoid manifestations, with more often neuro-ophthalmologic lesions than in other European populations.