Publikace vydané Univerzitou Pardubice / Published by the University of Pardubice
Stálý URI pro tuto komunituhttps://hdl.handle.net/10195/37631
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Článek Otevřený přístup peer-reviewedpublished Phenolic content and antioxidant activity of linden syrup prepared from dried flowers by hot and cold brewing(University of Pardubice, 2023) Červenka, Libor; Muriqi, Sali; Frühbauerová, Michaela; Adam, MartinLinden flower syrup has been used as a supportive treatment for colds in folk medicine. In this study, syrup was prepared by mixing sucrose and herbal infusion made by hot (HB) and cold (CB) brewing from air-dried (AD) and freeze-dried (FD) linden flowers. The syrup was preserved by heating at 75 °C for 25 min followed by storage at 5°C for 21 d. The colour, pH, phenolic content, and antioxidant activity were determined. Hot brewing produced syrups with a significantly higher amount of phenolics, flavonoids, and antioxidant activity than cold brewing. The contents of catechin (39.59 mg/L), epicatechin (159.07 mg/L), chlorogenic acid (44.66 mg/L) and tiliroside (1.92 mg/L) contents were higher for HB-FD than those of the HB-AD samples. Regarding cold brewing, it was found to effectively extract catechin, epicatechin, and chlorogenic acid from air-dried flower samples.Článek Otevřený přístup peer-reviewedpublished Voltammetry with a carbon paste electroactive electrode used for the quality assessment of vegetable oils(University of Pardubice, 2021) Horská, Anna; Švancara, Ivan; Sýs, Milan; Adam, MartinThis article introduces carbon paste electroactive electrodes in combination with voltammetric measurements as a useful tool for simple, low-cost, efficient, and semi-quantitative assessment of the quality of various vegetable oils. The respective method is based on anodic oxidation of electroactive organic compounds (namely: phenolic compounds and lipophilic vitamins) that naturally occur in the samples of interest and, in this case, being admixed in a small quantity directly into the carbon paste bulk. All the experiments were performed in 0.1 mol L−1 acetate buffer (pH 4.5) in the square-wave voltammetric mode. The results obtained have shown that the proposed procedure can be applied in food control to authenticate - as an electrochemical fingerprinting - the kind and the quality of a vegetable oil, including its freshness.Článek Otevřený přístup peer-reviewedpublished Colour, moisture adsorption, and antioxidant properties of oven-dried chokeberry powder obtained after ultrasound-assisted osmotic dehydration(University of Pardubice, 2021) Frühbauerová, Michaela; Červenka, Libor; Kosiorowska, Angelika; Królikowska, Karolina; Pająk, Paulina; Adam, MartinOsmotic dehydration (OD) of chokeberry samples in erythritol (ERT) and xylitol (XYL) solutions enhanced by ultrasonication (US) has been examined in terms of moisture adsorption, colour and antioxidant properties. After air-forced drying, the powder subjected to OD in ERT solution exhibited higher equilibrium moisture contents (EMC) in 0.20–0.45 aw than those in XYL solution. On the other hand, EMC values increased with the prolongation of US time from 5 to 30 min in the case of XYL solution. CIEL*a*b colour system was used for the determination of colour changes. While L* (the colour coordinate represents lightness (L* ~ 100) or darkness (L* ~ 0) of the sample) values decreased with the prolongation of US time from 5 to 30 min for both osmotic agents, only XYL solution caused the increase of a* (the colour coordinate represents green (−a*) or red (+a*) colour of the sample) and b* (the colour coordinate represents blue (−b*) or yellow (+b*) colour of the sample) to their maximum values at 30 min of sonication. A sample of powder subjected to OD in ERT solution has shown a higher total phenolic, total anthocyanin and antioxidant capacity. We may conclude that OD of chokeberries coupled with 30 min of sonication has resulted in chokeberry powder with the highest content of bioactive substances.Článek Otevřený přístup peer-reviewedpublished HILIC-MS analysis of common artificial sweeteners in food and beverages(University of Pardubice, 2021) Klikarová, Jitka; Štěpánová, Hana; Šimorová, Lenka; Česlová, Lenka; Fischer, Jan; Adam, MartinThe five most common artificial sweeteners were analysed in various samples of food and beverages and other products using hydrophilic-interaction liquid chromatography coupled with mass spectrometry. The optimised method employed Hypersil Gold HILIC analytical column combined with a binary mobile phase of 50 mmol/L ammonium acetate in water (pH 5; A)/acetonitrile (B) operating at a gradient program of 90–65 % B for 10 min. The individual sweeteners were quantified by the calibration curve method and the data obtained compared with the data declared on the packaging.Článek Otevřený přístup peer-reviewedpublished Biogenic amines in wine and cheese(University of Pardubice, 2021) Švecová, Blanka; Janovská, Miroslava; Adam, MartinBiogenic amines in ten samples of wine and five samples of cheese were determined using an HPLC-UV-MS method. Inevitable derivatization was performed with the reagent dansyl chloride, and the derivatives prepared were analysed under optimized chromatographic conditions in reversed phase mode. An octadecylsilicagel column (C18) was used for the separation of ten selected biogenic amines derivatives which were eluted using the mobile phase composed of 5 mM ammonium formate and acetonitrile at a flow-rate 0.6 mL min−1 and detected at the wavelength 254 nm. Basic validation of this method was carried out as well. Limits of detection and quantitation, external standard calibration, intra-day repeatability and inter-day reproducibility for spectrophotometric detection were determined. Five various red wines, four white wines and one rosé wine contained very small amounts of biogenic amines. The highest total content was approximately 2.5 mg L−1, which represents a relatively low content in comparison with some results published in literature. Similarly, the content of biogenic amines in cheeses analysed was lower than expected, even in case of fermented cheeses. The highest content was found in one of the typical Czech fermented cheeses called Romadur and being 3.9 mg in 100 g cheese.Článek Otevřený přístup peer-reviewedpublished Modeling and prediction of the gradient retention data for ultrahigh performance liquid chromatography of benzodiazepines(University of Pardubice, 2021) Valigurová, Petra; Váňová, Jana; Česla, Petr; Adam, MartinThis paper presents a method for prediction of the gradient retention times of six samples of benzodiazepines – phenazepam, pyrazolam, flubromazepam, meclonazepam, diclazepam, and diazepam. Isocratic and gradient separation of the compounds of interest was achieved on a Luna Omega C18 column followed by RP-LC/MS detection. The results have shown good agreement between the predicted and experimental retention data; however, higher differences were obtained for fast gradients in the ultrahigh performance separation mode.Článek Otevřený přístup peer-reviewedpublished Modification of boron-doped diamond electrode and its applications(University of Pardubice, 2021) Matvieiev, Oleksandr; Šelešovská, Renáta; Janíková, Lenka; Adam, MartinBoron doped diamond (BDD) is a promising electrode material exhibiting exceptional electrochemical properties. Thanks to this, it is widely used in the field of electroanalytical chemistry. Simultaneously, BDDE is an excellent substrate for various surface modifications that allow the improvement of specific properties of electrodes, such as sensitivity and selectivity in particular. This article presents a comprehensive overview of the possibilities of modification of BDDEs. It summarizes the different types of modifications in the individual chapters devoted to modifications with metal and metal oxide nanoparticles, carbon materials, such as graphene or carbon nanotubes, and last but not least, organic molecules and biomolecules. It also deals with procedures and specific conditions for electrode modification. Finally, an overview of applications of modified BDDEs is also included.Článek Otevřený přístup peer-reviewedpublished Multi-elemental analysis of wine samples using ICP-OES and ICP-MS methods. Anthropogenic gadolinium in wine(University of Pardubice, 2021) Mišíková, Frederika; Patočka, Jan; Krejčová, Anna; Adam, MartinThe study presented in this article has been focused on developing a method for elemental analysis of wine samples. A wide sample set of 200 wines contained white, rosé and red still wines; the wine vintages being 2013, 2014, 2015, 2016, 2017 and 2019. Samples were taken from wine festivals in Pardubice and Hradec Králové and private wineries in the Czech Republic. The analysis was performed using inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS); the determined elements being As, Ba, Ca, Cd, Ce, Co, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Lu, Mg, Mn, Na, Nd, Ni, P, Pb, Pr, S, Sm, Sr, Tb, Tm, Y, Yb, and Zn. The data obtained were processed statistically and the Sr/Ba, Sr/Ca and Sr/Mg ratios were determined as potential indicators for the identification and classification of the wine origin. The existence of the so-called gadolinium anomaly for selected wine samples was investigated as evidence of the presence of anthropogenic gadolinium.Článek Otevřený přístup peer-reviewedpublished Effects of polystyrene microparticles, gadolinium salts and their mixtures to soil annelid studied in agar exposure medium(University of Pardubice, 2021) Hrdá, Kateřina; Konopáčová, Eliška; Knotek, Petr; Adam, MartinEnvironmental risk assessment requires to conduct standardized ecotoxicological bioassays that can, at least, partially imitate realistic exposure scenarios. However, the study of the ecotoxic effects of particulate materials is complicated mainly by the fact that particles have different physical-chemical properties resulting in different distribution in the test medium in comparison with soluble pollutants. Therefore, in this study, the agar-based experimental system has been used to examine the toxicity of plastic microparticles to the soil decomposer Enchytraeus crypticus. Furthermore, of interest was the effect of the presence of plastic particles on the toxicity of gadolinium salts whose harmfulness to soil organisms is less known. The agar-based exposure medium enabled the consistent dispersion and agglomeration state of particles during the experiments under stable conditions with the characterization of the particles directly in the exposure medium. Gadolinium was tested in the form of Gd(NO3)3 and two contrast agents - Dotarem® (Acidum gadotericum) and MultiHance® (Dimeglumi gadobenas). The polystyrene particles (65–497 μm) were prepared by cryogenic grinding of coffee cup lids. The estimated 96h LC50 for gadolinium was higher than 1 g kg−1 of agar, which suggests a relatively low acute toxicity to E. crypticus. The polystyrene particles exhibited no toxicity to E. crypticus even at very high concentrations (1–25 g kg−1 of agar) after 10 days of exposure. The survival rate, the content of malondialdehyde in the biomass, or biomass production E. crypticus were not affected after 10-day of exposure to three different concentrations of Gd in the presence of particles.Článek Otevřený přístup peer-reviewedpublished Thermomechanical analysis as a useful tool to study photoinduced changes of the viscous flow of glassy materials(University of Pardubice, 2021) Smolík, Jan; Zmrhalová, Zuzana; Knotek, Petr; Černošková, Eva; Plecháček, Tomáš; Adam, MartinA modified thermomechanical analyzer is described as an useful tool to study the photoinduced changes in the viscous flow and thermal properties of glassy materials. The device proposed was tested on model chalcogenide glass As2S3 using the penetration method. Further, the article discusses and summarizes the effect of the light illumination (at wavelength of 650 nm) on the viscous flow at different temperatures below the glass transition temperature (Tg), and on the thermal behaviour interpreted from dilatometric curves via glass transition temperature and softening temperature.