Green Tea, made from Camellia sinensis plant leaves, is one of the most popular drinks in the world. For the past decades, scientists have studied this plant in terms of potential health benefits. Research has shown that green tea helps prevent stroke, malignancy and infections. In this paper, antioxidant activity and total phenol content of 4 samples of green tea from local Tuzla stores were investigated, of which two were of foreign origin. The antioxidant activity of the samples was analyzed using FRAP and DPPH methods. The obtained results show that the highest content of total phenols and the largest antioxidant capacity has a sample of foreign origin. The content of total phenols in the samples ranges from 60.01 to 79.34 mg GAE/g. The highest FRAP value is 3.34 mmol/g. The antioxidant capacity was also confirmed by the DPPH method. The IC50 value ranges from 0.014 to 0.030 mg/mL. Keywords-Phenol, FRAP, DPPH, Green Tea

Encapsulation can be defined as a process of entrapping one substance within another substance producing particles with diameters of a few nm to a few mm. The entrapped material is usually a liquid, but may be a solid or a gas. The main reason of using encapsulation is the fact that some nutrients do not remain in the food for a significant amount of time or may react with the other food components causing undesirable effects. It is possible to use micro- and nanoencapsulation techniques. The first one, microencapsulation, is a technology that can improve the retention time of the nutrient in the food and allow controlled release at specific times, during food consumption or in the intestinal gut (microencapsulation of vitamin). Nanoencapsulation has the potential to protect sensitive bioactive food ingredients from unfavourable environmental conditions, enhance solubilisation, improve taste and odour masking, and enhance bioavailability of poorly absorbable function ingredients. In this review, some relevant aspects of encapsulation methodologies, coating materials and their uses in food technology were discussed.

A Cloud point extraction (CPE) procedure was presented for preconcentration of lead(II) ions, after complexation by 18-crown-6 (18C6) and extraction with Triton X-100 at proposed experimental conditions. After separation of surfactant - rich phase, content of Pb(II) ions in remaining solution was measured by Flame Atomic Absorption Spectrometry (FAAS). The experimental conditions such as pH, temperature, concentration of Triton X-100, concentration of 18C6, incubation time, type and concentration of added electrolyte, were evaluated. Results showed that among investigated electrolytes (NaCl, Na2SO4 and Na2CO3) the amount of 0.9 mol/L Na2CO3 lowers cloud point temperature of Triton X-100 to 22?C (room temperature during the experiment), thus simplifying the extraction procedure. After an incubation time of 5 minutes and using the concentration of 1.2?10-3 mol/L Triton X-100 and 1.5?10-4 mol/L 18C6 (1:1 stoichiometric ratio for 18C6:Pb), 60% of lead (II) ions were efficiently removed from investigated solution.

: pABA (p-aminobenzoic acid or 4-aminobenzoic acid) is a chemical component of the folate mole-cule produced by plants and bacteria, and found in many foods. It is best known as a UV-blocking sunscreen applied to the skin, and is sometimes taken orally for certain medical conditions. Today it is known that many organic molecules in the human body can react with biometals such as copper, cobalt, manganese, iron and others. This study was performed to investigate the interaction of Cu(II) ions with p-aminobenzoic acid. Spectroscopic methods (FTIR and UV/Vis spectroscopy) were used to characterize the product obtained. The antimicrobial activity of the synthesized complex was tested by diffusion techniques. The results of spectroscopic analysis indicate the interaction of Cu(II) ions with pABA. Interaction is realized through oxygen donor atom of ligand. It was found that the Cu(II) complex has significant antimicrobial activity compared to the pABA ligand.

5 6 ABSTRACT 7 8 Aims: To investigate the competitive behavior of Cd(II) and Pb(II) ions within their equimolar mixtures, during transportation through a bulk liquid membrane, using macrocyclic carriers. Study design: Study was based on transport experiments, using homemade transport cell. Place and Duration of Study: Department of Analytical Chemistry, Faculty of Technology, between September 2017 and February 2018. Methodology: The bulk liquid membrane systems consisted of homemade transport cell constructed for transport of cations. Cell contained three separated phases: two aqueous and nonaqueous membrane phase between them. 1,2-dichloroethane (1,2-DCE) and dichloromethane (DCM) were used as liquid membranes. Macrocyclic ligands: dibenzo-18-crown-6 (DB18C6) and 18-crown-6 (18C6) were used as ligands for cations within the membranes. Both aqueous phases were buffered at pH = 5. Source phase contained an equimolar mixture of investigated metal ions and picrates as counter ions. Receiving phase contained thiosulphate as stripping agent. Duration of transport experiments were 3 hours and concentration of transported cations was measured using flame atomic absorption spectrometry. Results: Higher ligand selectivity for Pb(II) ions resulted with higher transport rates compared to Cd(II) ions: 63.25 % of Pb(II) > 51.80 % of Cd(II) using 18C6 in 1,2-DCE; 38.90 % of Pb(II) > 30.50 % of Cd(II) using DB18C6 in 1,2-DCE; 43.15 % of Pb(II) > 35.40 % of Cd(II) using 18C6 in DCM and 26.75 % of Pb(II) > 8.90 % of Cd(II) using DB18C6 in DCM. Higher selectivity of 18C6 as ionophore is also evident here. 1,2-DCE showed higher efficiency compared to DCM in competitive experiments (unlike individual experiments). Overall transport of Pb(II) in competitive experiments is lower compared to individual ones in DCM membrane: 40.30%<70.40% (with 18C6) and 26.75%<36.05% (with DB18C6). Overall transport of Cd(II) in competitive experiments is lower compared to individual ones in DCM membrane: 35.40%<48.10% (with 18C6) and 8.90<38.25% (with DB18C6). Conclusion: The results showed that higher ligand selectivity for Pb(II) ions lead to higher transport rates compared to Cd(II) ions from their equimolar mixtures. 18C6 was more selective for both cations as ionophore compared to DB18C6. 1,2-DCE showed higher efficiency as membrane solvent in competitive experiments compared to DCM, unlike the individual experiments. Competition between cations decreased their overall transport in DCM, but increased it in 1,2-DCE membrane. 9

Three Schiff bases were synthesized by reaction of different benzaldehydes with amino acids. The characterization of these compounds was performed using IR spectroscopy, molecular calculations, thin-layer chromatography, determining the melting point and other physical characteristics. IR spectra for imino groups (C=N), which are characteristic of Schiff bases, show stretching frequency from 1629 to 1654 cm-1. The obtained spectral results were confirmed by molecular calculations using the density functional theory (DFT) and were performed before experimental work. The DFT global chemical reactivity descriptors were calculated and used to predict their relative stability and reactivity of synthesized compounds. The antimicrobial assay of all compounds were screened for Grampositive bacteria species: Staphylococcus aureus ATCC 25923; Methicillin-resistant Staphylococcus aureus: MRSA ATCC 33591; Bacillus subtilis ATCC 6633; and Enterococcus faecalis ATCC 29212, Gram-negative: Salmonella enterica ATCC 31194; Pseudomonas aeruginosa ATCC 9027; Escherichia coli ATCC 25922; Extended Spectrum Beta-Lactamase producing E. coli: ESBL E. coli ATCC 35218, and one yeast Candida albicans ATCC 1023.The highest values of inhibition zones were recorded for compound1, followed by the compound 3, while compound 2 performed inhibitory effect just in case of MRSA. DFT calculations show that antimicrobial activity has a good correlation with chemical reactivity descriptors obtained Schiff bases.

Polymers based on polystyrene are widely used as thermoplastic materials due to the diversity in application, easy processability and a relatively low price. About 45% of the produced polystyrene is produced as compact and foamed products. Cellular foam polystyrene could be produced as expanded polystyrene (EPS) and extruded polystyrene (XPS) and is mainly used as insulation material. Therefore, physical and chemical properties of expanded and extruded polystyrene is of particular importance for thermal conductivity of the material. In this study, four types of expanded polystyrene were tested. Coefficient of thermal conductivity and the resistance of heat transfer were measured and compared to as well as mecahnical properties of the materials. It was confirmed that the density and thickness of the polystyrene influence the resistance of heat transfer.

The aim of this study was to determine the total phenolic content, evaluate antioxidant propertie and antimicrobial potential, and identify phenolic compounds in alcoholic and aqueous extracts of the wild cherry (Prunus avium L.) stems collected in Bosnia and Herzegovina. Alcoholic extracts had higher contents of phenolic and flavonoid components, as well as the antioxidant and ferric reducing antioxidant capacity in comparison to aqueous extracts. All extracts were characterized by HPLC analysis. Furthermore, for the first time, the antimicrobial properties of wild cherry stem extracts were evaluated. Quercetin and (+)-catechin were the main compounds identified in the alcoholic extract, followed by chlorogenic acid and rutin. Quercetin was also the major component detected in aqueous extracts. Besides, alcoholic extract showed better antibacterial properties against Staphylococcus aureus as a representative gram-positive bacteria than infusion, whereas none of the samples showed antibacterial activity against Escherichia coli and fungus Candida albicans.