Search

Uvod: Kofein je prirodni alkaloid, izolovan iz više od 60 biljnih vrsta. Preko 80 % svetske populacije svakodnevno unosi kofein u organizam kroz konzumaciju kafe, čajeva, čokolade i, u poslednje vreme, energetskih pića. Ne treba zanemariti činjenicu da kofein, kao farmakološki aktivna supstanca, ulazi u sastav mnogih lekova koji se na tržištu Republike Srbije izdaju bez lekarskog recepta. Sem toga, kofein je psihoaktivni stimulans, blag je diuretik i pokazuje interakciju sa nekim lekovima usled indukcije CYP1 i CYP2 izoenzima, zbog čega je potrebno voditi računa o količini koja se unese u organizam. U skladu s tim, važno je i da sadržaj kofeina u energetskim pićima odgovara podacima koje proizvođači navode na deklaraciji. Cilj: Cilj ovog rada bio je spektrofotometrijsko određivanje sadržaja kofeina u uzorcima energetskih pića i čajeva proizvođača dostupnih na tržištu R. Srbije. Materijal i metode: Kofein je određivan metodom ultraljubičaste i vidljive (UV/VIS) spektrofotometrije u devet vrsta energetskih pića i po četiri uzorka crnog i zelenog čaja. Rezultati: U uzorcima energetskih pića određeni sadržaj kofeina je u opsegu od 26,81 do 35,44 mg/100 mL i u skladu je s deklarisanim sadržajem. Sadržaj kofeina u uzorcima čajeva varira u odnosu na vrstu (11,27-22,61 mg/100 mL zeleni i 13,85-22,73 mg/100 mL crni), ali je vezan i za poreklo, uslove gajenja i proces prerade čajeva. Zaključak: Ultraljubičasta i vidljiva spektrofotometrija se pokazala kao brza, precizna i jednostavna metoda za određivanje kofeina u energetskim pićima i čajevima. Imajući u vidu dobijene rezultate, važno je istaći da unos kofeina kroz uobičajenu dnevnu konzumaciju čajeva i energetskih pića ne bi trebalo da utiče negativno na zdravlje ljudi. Svakako treba imati u vidu da se ovaj alkaloid dodatno može uneti i putem drugih izvora, što je posebno važno za određene grupe pacijenata. Introduction: Caffeine is a natural alkaloid, isolated from more than 60 plant species. Over 80% of the world’s population consumes caffeine on daily basis through the consumption of coffee, tea, chocolates and, more recently, energy drinks. As a pharmacologically potent substance caffeine is an ingredient of many medicaments available on the pharmaceutical market of Republic of Serbia without a doctor’s prescription. Besides that, caffeine acts as a psychoactive stimulant, mild diuretic, and displays an interaction with some medicaments due to the induction of CYP1 and CYP2 isoenzymes. Keeping in mind all of the above, it is necessary to take into account the daily caffeine intake, as well as to control its content in energy drinks.Aim: The aim of this study was spectrophotometric determination of caffeine content in energy drinks and tea, available in markets of the Republic of Serbia. Material and Methods: Caffeine was determinated by UV/VIS spectrophotometry in nine types of energy drinks and eight samples of black and green tea. Results: The results showed that caffeine content in energy drink samples ranged from 26.81 to 35.44 mg/100mL and corresponds to declaration. The caffeine content in tea samples varies with the species (11.27-22.61 mg/100mL for green and 13.85-22.73 mg/100mL for black tea), but also with origin, growth conditions and tea processing.Conclusion: The obtained data suggest that UV/VIS spectrophotometry can be used for ro-utine determination and control of caffeine content in energy drinks and tea. It is important to note that caffeine intake through the usual daily consumption of tea and energy drinks should not have a negative impact on human health, but this alkaloid could be additionally consumed through other sources, which is especially important for certain groups of patients.

A chemical characterization and biological activity of 7 honey types (multifloral, linden, rapeseed, sunflower,phacelia, acacia and honeydew honey) from different regions of Serbia were presented. The physicochemicalcharacteristics, mineral content, antioxidant and antimicrobial activity were estimated and discussed. All honeysshowed good nutritional characteristics, according to the adopted criteria of the standard codex for honey. Theconcentrations of 15 elements in honey samples were determined using inductively coupled plasma opticalemission spectroscopy (ICP-OES). Limits of quantification were in the range from 0.003 mg/kg (Cd, Cr, Cu, Mn,and Pb) to 1.50 mg/kg for sodium. Precision was expressed as relative standard deviation and its values werelower than 1.50%. Accuracy was evaluated with certified reference material (fish protein, DORM 4, NRC andcooking chocolate, SRM 2384, NIST) and obtained recovery percentages were 71-127%. The content of the mostabundant elements (K, Mg, and Na) and microelements (Al, Cu, Fe, Mn, Ni, Se, Si, and Zn) showed a significantvariability in accordance of their botanical and geographical origin, but also the influence of harvest conditions.The levels of toxic metals (As, Cd, Cr, and Pb) are much lower than the maximal allowed for these metalsaccording to European Commission Regulation. The antioxidant activity was evaluated by DPPH(Diphenylpicrylhydrazyl) assay while antimicrobial activity against Gram positive and Gram negative bacteria(E. coli and S. aureus) and fungi Candidi albicans was estimated by microdilution assay. The free radicalscavenging assay (%RSA) varies significantly among the honey samples. The highest antioxidant activity wasobserved with honeydew honeys (over 75% RSA) and the lowest was observed in the acacia, ranging from 22.96to 24.57% RSA. All honeys tested in this study exhibited antibacterial activity, with inhibition of bacterialgrowth, generally the higher against E. coli (80% for linden honeys) than against S. aureus (mostly much lowerthan 50%). Activity against Candidi albicans was almost negligible. The dataset composed of all experimentalresults was subjected to a chemometric evaluation and cluster analysis as hierarchical nonsupervised methodwas applied. According to the obtained outcome of applied algorithms, both botanical and geographical originhave important role in the elemental composition, antioxidant and antimicrobial activities. This is the peer-reviewed version of the following article: Đogo Mračević, S.; Krstić, M.; Lolić, A.; Ražić, S. Comparative Study of the Cheical Composition and Biological Potential of Honey from Different Regions of Serbia. Microchemical Journal 2020, 152, 104420. [https://doi.org/10.1016/j.microc.2019.104420]. Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4996]

The improvement of living standards has a significant impact on food and food production. Meat and meat products, due to their high nutritional value, are an important segment of human nutrition and a rich source of elements such as Fe, Zn, Mn, Ca, K, Mg. On the other hand, meat can accumulate heavy metals such as Cd and Pb. Toxic metal concentrations in the muscles are rare, but the liver and kidneys have an ability of accumulation. Nitrites are very important in the meat industry as additives and preservatives, but downside effects of nitrite addition are the development of toxic and carcinogenic nitrosoamine. In monitoring the quality of meat and meat products, it is important to keep track of metal content, but also the residual concentration of nitrite. The aim of this study was to determine the content of Cd, Cu, Fe, and Zn in samples of pork and beef meat and pig liver and the content of nitrites in samples of pork and beef meat and meat products - patches and sausages. Metals were determined using the ICP-AES method and nitrate by the standard method SRPS ISO 2918/1999. The content of iron in the liver, pork and beef meat is 189.2 μg / kg, 89.78 μg / kg and 87.79 μg / kg respectively. The content of Cu and Zn in all tested samples is below MAC values, and Cd in pork meat sample is 1.2 times more than MAC values. The content of nitrite is below the MAC values and represents the residual concentration of these compounds.

Binary polymeric amorphous carvedilol solid dispersions were prepared using solvent method by varying solvent type, polymer type and carvedilol to polymer ratio in order to assess the influence of these factors and maximize carvedilol dissolution rate. Low and high molecular weight polyvinylpyrrolidone, polyvinylpyrrolidone-vinyl acetate copolymer and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer were used as polymeric carriers in carvedilol to polymer ratios 1:1, 1:2 or 1:4, while absolute ethanol or acetone were used as solvents. Hard gelatin capsules were prepared with carvedilol solid dispersion and lactose monohydrate, mannitol or microcrystalline cellulose. FTIR and PXRD were used to detect carvedilol crystallinity and identify carvedilol-polymer interactions and carvedilol polymorphs. These techniques confirmed carvedilol transition to amorphous state and suggested that hydrogen bonds were formed between carvedilol and polymer molecules. Carvedilol dissolution rate was significantly higher from solid dispersions with higher carvedilol to polymer ratio and solid dispersions prepared using the solvent in which the polymer was more soluble. Solid dispersion with polyvinylpyrrolidone-vinyl acetate copolymer in 1:4 ratio in absolute ethanol displayed the highest carvedilol dissolution rate with 91.78% carvedilol dissolved in the first 30 min. Capsules prepared with the selected solid dispersion and microcrystalline cellulose as diluent displayed the highest carvedilol dissolution rate, with 93.43% carvedilol dissolved within the first 30 min. Carvedilol bioavailability was significantly increased by formulating solid dispersions, while the analysis of serum biochemical parameters excluded damage on liver and kidney function and the lipid profile of animals exposed to investigated drug delivery system.

Determination of sugars, especially in fruit juices, is very significant bearing in mind their nutritive importance and the increased demands in food control, especially for fractions of carbohydrates in fresh products. Home-made juices as 'functional food' are in the focus of scientific attention because of the expansion of industrial manufacturing of fruit juices and importance of monoand disaccharides stability for the products quality. In this work determination of content of basic sugars in fruit juices, by applying a high performance liquid chromatography (HPLC), was performed. Content of glucose, fructose and saccharose was analysed in currant, cherry, peach, apricot and strawberry juices as well as in home-made cherry and apricot syrups. Quantification was based on comparison of chromatograms of standard solutions of saccharose, glucose and fructose with our samples. With isocratic elution applied temperature was 90˚C, water as a mobile phase and column Nucleogel Sugar Ca, refractometric detection was applied. The obtained results showed that concentrations of gucose, fructose and saccharose vary in the range 3,149-38,405 g/100 mL, 1,931-30,851 g/100 mL and 0,670-6,072 g/100 mL, respectively. Concerntrations of glucose and fructose do not exhibit significant variations in juices however, they are ten times higher in syrups. In all samples, juices and syrups, concentrations of saccharose do not differ significantly, except for one syrup sample where much lower content could be explained with possible enzymatic decomposition. Određivanje šećera u voćnim sokovima je veoma važno, imajući u vidu njihov nutritivni značaj, ali i povećane zahteve u kontroli hrane kada su u pitanju pojedine frakcije ugljenih hidrata u sveže pripremljenim proizvodima. S obzirom na to da postoji porast industrijske proizvodnje voćnih sokova i značaj stabilnosti monoi disaharida za kvalitet proizvoda, domaći sokovi, kao funkcionalna hrana, postaju sve značajniji. U ovom radu je analiziran sadržaj osnovnih šećera u voćnim sokovima i sirupima kućne izrade primenom visokoefikasne tečne hromatografije (HPLC). Analiziran je sadržaj glukoze, fruktoze i saharoze u sokovima od ribizle, višnje, breskve, kajsije i jagode, kao i u sirupima od višnje i kajsije. Određivanje se zasnivalo na poređenju hromatograma rastvora standarda šećera i naših uzoraka. Uz izokratsko eluiranje analiza je izvođena pri temperaturi od 90 ˚C. Sa vodom kao mobilnom fazom i kolonom Nucleogel Sugar Ca, primenjena je refraktometrijska detekcija. Analizom je pokazano da sadržaj glukoze, fruktoze i saharoze varira u rasponu 3,149-38,405 g/100 ml, 1,931-30,851 g/100 ml i 0,670-6,072 g/100 ml, respektivno. Sadržaj glukoze i fruktoze se ne razlikuje značajno između sokova, a u sirupima je za deset puta veći. Sadržaj saharoze takođe se ne razlikuje značajno među ispitivanim uzorcima, osim u jednom sirupu zbog najverovatnije enzimske razgradnje ovog šećera.