Reakcijom klora pri dezinfekciji vode za pice s prirodnim organskim tvarima iz vode (NOM, natural... more Reakcijom klora pri dezinfekciji vode za pice s prirodnim organskim tvarima iz vode (NOM, natural organic matter) nastaju razliciti dezinfekcijski stetni produkti kao sto su trihalogenmetani, halogenoctene kiseline, halogenaldehidi, halogenketoni, halogenacetonitrili, klorfenoli i dr. Toksicna i potencijalna kancerogena svojstva kloriranih i bromiranih trihalogenmetana (THM) razlogom su definiranja maksimalno dopustenih koncentracija (MDK) u vodi za pice i nužnosti njihovog određivanja prilikom ocjene zdravstvene ispravnosti vode za pice. Nastajanje trihalogenmetana u vodi za pice ovisi o koncentraciji klora koji se koristi u postupku dezinfekcije vode, vremenu kontakta između klora i vode, koncentraciji halogenida i organskih tvari prisutnih u samoj vodi, pH vode, temperaturi i dr. U ovom su radu utvrđene povisene koncentracije organskih tvari u nekim vodoopskrbnim sustavima istocne Hrvatske i bosanske Posavine određivanjem ukupnog organskog ugljika (TOC), spektrofotometrijskih analiza apsorpcije vidljivog i UV svijetla za analizu aromatskih kromofora u NOM i utvrđen potencijal stvaranja THM, koncentracije halogenida (klora, broma i fluora u vodi) ionskim kromatografom, a pracene su i koncentracije klora kod dezinfekcije, radi razumijevanja procesa nastajanja trihalogenmetana u vodi. Trihalogenmetani su određeni plinskom kromatografijom uz koristenje ECD (Electron – Capture Detector) detektora standarnim ISO metodama. Kroz nekoliko mjeseci tijekom 2004. godine analizirane su koncentracije i karakteristike prirodnih organskih tvari iz vode, halogenidi kao i nastali trihalogenmetani: triklormetan, bromdiklormetan, dibromklormetan i tribrommetan u vodi za pice nakon kloriranja u nekoliko vodoopskrbnih sustava istocne Hrvatske i bosanske Posavine i utvrđen utjecaj na formiranje THM.
Production of extrudates from different types of flour is now used widely in the food process ind... more Production of extrudates from different types of flour is now used widely in the food process industry, both for final products production and for modification of flours for bakery industry. The aim of this research was to determine the effect of extrusion process on the properties of mixtures of corn meal with buckwheat and chestnut flour (ratio meal: flour = 70/30, 50/50 and 30/70). Blends (water content 25%) were extruded at two temperature regimes: 80/90 °C and 75/180 °C. Physical, thermophysical and rheological properties, chemical composition and resistant starch content of the obtained extrudates were investigated. Results showed an increase in expansion ratio and the reduction of bulk mass at the higher extrusion temperature, increased fragility and decreased hardness of most of extrudates produced at the higher temperatures. In relation to non-extruded samples, color intensity and water absorption index increased proportionally to extrusion temperature. Viscosity changed significantly, and resistant starch (RS) content decreased by extrusion.
Fluoride is a natural component of groundwater resources and has considerable impact on human hea... more Fluoride is a natural component of groundwater resources and has considerable impact on human health. Epidemiological studies showed that low concentration of fluoride (below 0.5 mg/L) in drinking water leads to dental caries while fluoride content of between 0.5 and 1.5 mg/L promotes dental health. It was also reported that the assimilation of fluoride from drinking water with concentrations above 1.5 mg/L might result in dental, skeletal and crippling fluorosis. Dental fluorosis is the most common manifestation of chronic use of high fluoride water and it has the greatest impact on the growing teeth, particularly on children under seven years of age. On the other hand, the fluoride content in the groundwater is a function of many factors such as pH, temperature, dissolution of natural minerals in the rocks and soils with which water interacts. For all reasons mentioned, the aim of this study is to present a systematic approach to evaluate the distribution of fluoride in the groundwater of Brcko Distrikt. The samples were collected from 61 groundwater sources (1580 samples) during 2004 – 2008. The fluoride concentration was determined by ion chromatography with chemical suppression of eluent conductivity using the ISO 10304-1 method. The obtained results showed that the concentrations of fluoride found in the studied groundwater ranged between 0.024 to 1.085 mg/L, and the average value is 0.428 mg/L. The minimum fluoride content in all samples of this region was measured in June 2007, while the maximum fluoride value was in February 2004. Furthermore, the mean fluoride value of year did not change significantly within the five years (0.402 – 0.456 mg/L), and only all measured concentrations in 2005 were below 1 mg/L. It is also observed that about 75% of the investigated groundwaters contain less than 0.5 mg/L fluoride. The obtained results demonstrate that the concentrations of fluoride in all samples were below the maximum permissible limit (1.5 mg/L) established by WHO for this essential component. Our study suggests in general that the fluoride concentration in groundwater of Brcko is low. Furthermore, the results indicated that total daily fluoride intake by people living in this region needs to be determined, and a research program in this regard has been initiated.
Blackberry wine, a popular fruit wine, is a product of yeast fermentation of natural sugars prese... more Blackberry wine, a popular fruit wine, is a product of yeast fermentation of natural sugars present in blackberry juice, well known natural source of vitamins. It was shown that blackberry variety, technology of manufactoring and duration of wine storage have influence on amounts of vitamins present in wine. Today, HPLC methods are the most often used for the determination of water-soluble vitamins for evaluation and quality control of wines. Major advantage of these chromatographic methods is their ability to separate different forms of vitamins from very complicated matrix, such as blackberry wine. The contents of ascorbic acid, thiamine, riboflavin, nicotinic acid, pyridoxine and folic acid were determined in fifteen samples of blackberry wine from different regions of Croatia. All samples were filtered through Minisart RC4, 0.45 µ m filters (Sartorius), which did not retain any of the analytes. The samples were injected after filtration or after dilution with 1 M phosphate buffer, pH 5.5. The chromatographic system consisted of a Dionex HPLC Pump P680, Automated Sample Injector ASI-100, Termostatted Column Compartment TCC-100 and UVD340U PDA Detector. Vitamins were separated on a Zorbax SB-C18 (250 x 4.6 mm, 5 µ m ; Agilent Technologies) with suitable guard column. The following solvents were used: solvent A (50 mM sodium phosphate buffer (pH 2.5):MeOH, 90:10, v/v) and solvent B (50 mM sodium phosphate buffer (pH 2.5):MeOH, 10:90, v/v). The mobile phase was filtered and degassed ultrasonically prior to use. The gradient was linearly changed from 0 to 70% B in 22 min, with a post-run time of 3 min (100% B) and a constant flow rate of 1 mL min-1. The column temperature was maintained at 20 °C, the injection volume was 10 µ ; l and the detector was set at 223 nm for folic acid and riboflavin, 245 nm for thiamine and ascorbic acid, 268 nm for nicotinic acid and 292 nm for pyridoxine. Vitamin standards were used to generate characteristic UV-VIS spectra and calibration curves. The analyses were performed in triplicate. Optimized HPLC method with UV detection was validated through linearity, sensitivity, selectivity and repeatability, and it was shown that this method can be used for routine analysis of six vitamins in blackberry wine.
A comparison of two extraction methods, liquid- liquid extraction andQuEChERS methodology, for th... more A comparison of two extraction methods, liquid- liquid extraction andQuEChERS methodology, for the analysis of polyphenol content in olive oil was conducted.
The gas chromatographic analysis of volatile compounds in blackberry wine is a very important too... more The gas chromatographic analysis of volatile compounds in blackberry wine is a very important tool useful for wine classification, quality control and sensory evaluation of wines. Aroma of blackberry wine is produced by a complex balance of several volatile compounds, such as hydrocarbons, alcohols, terpene alcohols, esters, aldehydes, ketones, acids, ethers, lactones, sulphurous and nitrogenous compounds. The composition of the volatile fraction of wine depends on factors like blackberry variety, soil, climate, vintage year and winery procedures. On the other hand, wines are taxed, in large part, based on their alcohol levels and it is well known that methanol is a toxic and harmful substance to human health. Methanol, ethanol, ethyl acetate, propan-1-ol, amyl alcohol and isoamyl alcohol were analysed in 15 blackberry wines using Agilent GC-6850 gas chromatograph equipped with a flame ionisation detector. A bottle of each wine was opened and a sample with no pre-treatment was immediately injected in triplicate. The chromatographic conditions were as follows: column, HP-1 (Agilent Technologies, 30 m x 0.32 mm I.D., film thickness, 0.25 μ m) ; the injection volume was set at 1.0 μ L, the split ratio was 1:5 ; the temperature of the inlet, 230 o C. The column head pressure was 2.33 psi and the nitrogen carrier gas flow rate was 0.5 mL min-1. The average nitrogen gas velocity was 10 cm s-1. The oven temperature was at 26 o C for 7 min, then increased from 26 o C to 50 o C at a rate of 1 o C min-1, after that increased to a final temperature of 200 o C (rate of 15 o C min-1) and held for 4 min isothermally. The FID temperature was 250 o C and the flow rate of hydrogen carrier gas was 25 mL min-1. Validation of the method was carried out for linearity, repeatability, selectivity and sensitivity. The developed method can be used successfully to determine several volatile compounds in blackberry wine.
Reakcijom klora pri dezinfekciji vode za pice s prirodnim organskim tvarima iz vode (NOM, natural... more Reakcijom klora pri dezinfekciji vode za pice s prirodnim organskim tvarima iz vode (NOM, natural organic matter) nastaju razliciti dezinfekcijski stetni produkti kao sto su trihalogenmetani, halogenoctene kiseline, halogenaldehidi, halogenketoni, halogenacetonitrili, klorfenoli i dr. Toksicna i potencijalna kancerogena svojstva kloriranih i bromiranih trihalogenmetana (THM) razlogom su definiranja maksimalno dopustenih koncentracija (MDK) u vodi za pice i nužnosti njihovog određivanja prilikom ocjene zdravstvene ispravnosti vode za pice. Nastajanje trihalogenmetana u vodi za pice ovisi o koncentraciji klora koji se koristi u postupku dezinfekcije vode, vremenu kontakta između klora i vode, koncentraciji halogenida i organskih tvari prisutnih u samoj vodi, pH vode, temperaturi i dr. U ovom su radu utvrđene povisene koncentracije organskih tvari u nekim vodoopskrbnim sustavima istocne Hrvatske i bosanske Posavine određivanjem ukupnog organskog ugljika (TOC), spektrofotometrijskih analiza apsorpcije vidljivog i UV svijetla za analizu aromatskih kromofora u NOM i utvrđen potencijal stvaranja THM, koncentracije halogenida (klora, broma i fluora u vodi) ionskim kromatografom, a pracene su i koncentracije klora kod dezinfekcije, radi razumijevanja procesa nastajanja trihalogenmetana u vodi. Trihalogenmetani su određeni plinskom kromatografijom uz koristenje ECD (Electron – Capture Detector) detektora standarnim ISO metodama. Kroz nekoliko mjeseci tijekom 2004. godine analizirane su koncentracije i karakteristike prirodnih organskih tvari iz vode, halogenidi kao i nastali trihalogenmetani: triklormetan, bromdiklormetan, dibromklormetan i tribrommetan u vodi za pice nakon kloriranja u nekoliko vodoopskrbnih sustava istocne Hrvatske i bosanske Posavine i utvrđen utjecaj na formiranje THM.
Production of extrudates from different types of flour is now used widely in the food process ind... more Production of extrudates from different types of flour is now used widely in the food process industry, both for final products production and for modification of flours for bakery industry. The aim of this research was to determine the effect of extrusion process on the properties of mixtures of corn meal with buckwheat and chestnut flour (ratio meal: flour = 70/30, 50/50 and 30/70). Blends (water content 25%) were extruded at two temperature regimes: 80/90 °C and 75/180 °C. Physical, thermophysical and rheological properties, chemical composition and resistant starch content of the obtained extrudates were investigated. Results showed an increase in expansion ratio and the reduction of bulk mass at the higher extrusion temperature, increased fragility and decreased hardness of most of extrudates produced at the higher temperatures. In relation to non-extruded samples, color intensity and water absorption index increased proportionally to extrusion temperature. Viscosity changed significantly, and resistant starch (RS) content decreased by extrusion.
Fluoride is a natural component of groundwater resources and has considerable impact on human hea... more Fluoride is a natural component of groundwater resources and has considerable impact on human health. Epidemiological studies showed that low concentration of fluoride (below 0.5 mg/L) in drinking water leads to dental caries while fluoride content of between 0.5 and 1.5 mg/L promotes dental health. It was also reported that the assimilation of fluoride from drinking water with concentrations above 1.5 mg/L might result in dental, skeletal and crippling fluorosis. Dental fluorosis is the most common manifestation of chronic use of high fluoride water and it has the greatest impact on the growing teeth, particularly on children under seven years of age. On the other hand, the fluoride content in the groundwater is a function of many factors such as pH, temperature, dissolution of natural minerals in the rocks and soils with which water interacts. For all reasons mentioned, the aim of this study is to present a systematic approach to evaluate the distribution of fluoride in the groundwater of Brcko Distrikt. The samples were collected from 61 groundwater sources (1580 samples) during 2004 – 2008. The fluoride concentration was determined by ion chromatography with chemical suppression of eluent conductivity using the ISO 10304-1 method. The obtained results showed that the concentrations of fluoride found in the studied groundwater ranged between 0.024 to 1.085 mg/L, and the average value is 0.428 mg/L. The minimum fluoride content in all samples of this region was measured in June 2007, while the maximum fluoride value was in February 2004. Furthermore, the mean fluoride value of year did not change significantly within the five years (0.402 – 0.456 mg/L), and only all measured concentrations in 2005 were below 1 mg/L. It is also observed that about 75% of the investigated groundwaters contain less than 0.5 mg/L fluoride. The obtained results demonstrate that the concentrations of fluoride in all samples were below the maximum permissible limit (1.5 mg/L) established by WHO for this essential component. Our study suggests in general that the fluoride concentration in groundwater of Brcko is low. Furthermore, the results indicated that total daily fluoride intake by people living in this region needs to be determined, and a research program in this regard has been initiated.
Blackberry wine, a popular fruit wine, is a product of yeast fermentation of natural sugars prese... more Blackberry wine, a popular fruit wine, is a product of yeast fermentation of natural sugars present in blackberry juice, well known natural source of vitamins. It was shown that blackberry variety, technology of manufactoring and duration of wine storage have influence on amounts of vitamins present in wine. Today, HPLC methods are the most often used for the determination of water-soluble vitamins for evaluation and quality control of wines. Major advantage of these chromatographic methods is their ability to separate different forms of vitamins from very complicated matrix, such as blackberry wine. The contents of ascorbic acid, thiamine, riboflavin, nicotinic acid, pyridoxine and folic acid were determined in fifteen samples of blackberry wine from different regions of Croatia. All samples were filtered through Minisart RC4, 0.45 µ m filters (Sartorius), which did not retain any of the analytes. The samples were injected after filtration or after dilution with 1 M phosphate buffer, pH 5.5. The chromatographic system consisted of a Dionex HPLC Pump P680, Automated Sample Injector ASI-100, Termostatted Column Compartment TCC-100 and UVD340U PDA Detector. Vitamins were separated on a Zorbax SB-C18 (250 x 4.6 mm, 5 µ m ; Agilent Technologies) with suitable guard column. The following solvents were used: solvent A (50 mM sodium phosphate buffer (pH 2.5):MeOH, 90:10, v/v) and solvent B (50 mM sodium phosphate buffer (pH 2.5):MeOH, 10:90, v/v). The mobile phase was filtered and degassed ultrasonically prior to use. The gradient was linearly changed from 0 to 70% B in 22 min, with a post-run time of 3 min (100% B) and a constant flow rate of 1 mL min-1. The column temperature was maintained at 20 °C, the injection volume was 10 µ ; l and the detector was set at 223 nm for folic acid and riboflavin, 245 nm for thiamine and ascorbic acid, 268 nm for nicotinic acid and 292 nm for pyridoxine. Vitamin standards were used to generate characteristic UV-VIS spectra and calibration curves. The analyses were performed in triplicate. Optimized HPLC method with UV detection was validated through linearity, sensitivity, selectivity and repeatability, and it was shown that this method can be used for routine analysis of six vitamins in blackberry wine.
A comparison of two extraction methods, liquid- liquid extraction andQuEChERS methodology, for th... more A comparison of two extraction methods, liquid- liquid extraction andQuEChERS methodology, for the analysis of polyphenol content in olive oil was conducted.
The gas chromatographic analysis of volatile compounds in blackberry wine is a very important too... more The gas chromatographic analysis of volatile compounds in blackberry wine is a very important tool useful for wine classification, quality control and sensory evaluation of wines. Aroma of blackberry wine is produced by a complex balance of several volatile compounds, such as hydrocarbons, alcohols, terpene alcohols, esters, aldehydes, ketones, acids, ethers, lactones, sulphurous and nitrogenous compounds. The composition of the volatile fraction of wine depends on factors like blackberry variety, soil, climate, vintage year and winery procedures. On the other hand, wines are taxed, in large part, based on their alcohol levels and it is well known that methanol is a toxic and harmful substance to human health. Methanol, ethanol, ethyl acetate, propan-1-ol, amyl alcohol and isoamyl alcohol were analysed in 15 blackberry wines using Agilent GC-6850 gas chromatograph equipped with a flame ionisation detector. A bottle of each wine was opened and a sample with no pre-treatment was immediately injected in triplicate. The chromatographic conditions were as follows: column, HP-1 (Agilent Technologies, 30 m x 0.32 mm I.D., film thickness, 0.25 μ m) ; the injection volume was set at 1.0 μ L, the split ratio was 1:5 ; the temperature of the inlet, 230 o C. The column head pressure was 2.33 psi and the nitrogen carrier gas flow rate was 0.5 mL min-1. The average nitrogen gas velocity was 10 cm s-1. The oven temperature was at 26 o C for 7 min, then increased from 26 o C to 50 o C at a rate of 1 o C min-1, after that increased to a final temperature of 200 o C (rate of 15 o C min-1) and held for 4 min isothermally. The FID temperature was 250 o C and the flow rate of hydrogen carrier gas was 25 mL min-1. Validation of the method was carried out for linearity, repeatability, selectivity and sensitivity. The developed method can be used successfully to determine several volatile compounds in blackberry wine.
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