This thesis deals with the determination of aroma active compounds in non-chocolate confectionery and their influence on the sensory properties of these sweets. The theoretical part is focused on the 26 potentially allergenic substances and their determination by SPME-GC-FID (a solid phase microextraction, gas chromatography with flame ionisation detector) and sensory analysis. In the experimental part SPME-GC-FID method was used to identify and quantify aroma active substances contained in the selected samples of confectioneries commonly available in food market and find out influence of presence and amounts of these substances on sensory profile of selected confectionery.

The thesis deals with monitoring of the yeast's impact to the chemical and sensorial characteristics of produced wine. The aim of experimental part was obtaining of the aroma-active substances in the fermenting must and wine Hibernal and wine Pinot Blanc. SPME-GC-MS methods were used for identify wines and must aroma. The same autochthonous yeasts were used for wine production. This yeast was isolated from surface of grapes in our laboratory. It was found that both wines have a similar aromatic profile. The next aim was the monitoring of chemical parameters of samples and their changes. For this measurement were used spectrophotometric methods and HPLC methods. The last goal of the thesis was the isolation and identification of yeasts from wine Pinot Blanc by PCR-RFLP. These yeasts were then compared with yeasts isolated from Hibernal must. Identification of yeasts were done by amplification 5,8S-ITS DNA stretches using primers ITS1 and ITS4. Restriction endonuclease HaeIII, HinfI, HhaI and TaqI. were used for restriction analysis then.

This thesis deals with aroma active compounds of selected types of medicinal herbs, specifically lavender (Lavandula officinalis), peppermint (Mentha piperita), sage (Salvia officinalis), St. John’s wort (Hypericum perforatum) and hyssop (Hyssopus officinalis). In the theoretical part the single herbs were characterized including botanical description, chemical composition, medicinal properties, adverse effects and the practical use; aroma active compounds present in herbs are also emphasized. Based on the literature search, gas chromatography coupled with mass spectrometry as currently the most frequently used method, was chosen for the assessment of aroma compounds. Solid Phase Microextraction was used for isolation of volatile compounds from dried herbs. Within experimental part of the work selected parameters of the SPME-GC-MS method were optimized, aroma compounds in samples of herbs were identified, and twenty four suspected fragrance allergens due to the Regulation (EC) N° 1223/2009 were also identified and quantified. Overall 69 compounds were indetified together with 2 allergens in lavender, 59 compounds including 5 allergens in peppermint, sage contained 49 compounds with 4 allergens included, 41 compounds were identified in St. John’s wort including 4 allergens and finally 64 compounds with 4 allergens included in hyssop.

The aim of the work was identification of aroma active compounds in Moravský bochník cheese type, than discuss their changes during ripening and consider influence of aplication different rates of microbial cultures on number of volatile compounds. SPME-GC-MS was used for identification of volatile compounds. In total, 148 of volatile compounds were identified and 82 of them are considered as aroma active compounds. Three microbial cultures (their combination with predominant thermophilic or mesophilic culture) were used for making samples. The influence of predominant thermophilic/mesophilic culture on number of volatile compounds was not proved. From the point of view of sensory quality, combinations with predominant mesophilic culture proved to be more successful. During ripening, the number of identified compounds was reduced in all the combinations of cultures studied. The optimal time for ripening seems to be three months.

Naphthenic acids (NAs) are oil-derived mixtures of carboxylic acids and are aquatic contaminants of emerging concern. The objective of the research presented in this thesis was to investigate the toxicity of NAs in tadpoles of the frog Silurana (Xenopus) tropicalis. Using electrospray ionization high-resolution mass spectrometry (ESI-HRMS), I determined that the proportions of O2 (presumably carboxylic acid moiety) species were 98.8, 98.9 and 58.6% respectively, for two commercial extracts (S1 and S2), and acid extractable organics (AEOs) from oil sands process-affected water (OSPW). The rank order potency based on the lethal concentration fifty (LC50) and effect concentration fifty (EC50) with and without normalization for the quantity of O2 species was S1 > S2 > AEO. The main effects observed were reduced body size, edema, and cranial, cardiac, gut and ocular abnormalities. Oligonucleotide microarray technology was used to determine the transcriptomic responses in developing S. tropicalis embryos following exposure to S1 and S2 at a sub-lethal concentration of 2 mg/L. Some of the significantly enriched pathways (p < 0.05) included metabolism and cell membrane depolarization, and some were related to observed abnormalities including edema, gastrointestinal system, and cartilage differentiation. I established and validated a derivatization method for NAs using pentafluorobenzyl bromide (PFBBr) prior to gas chromatography-electron impact mass spectrometry (GC-EIMS) to increase chromatographic resolution, and sensitivity, compared to boron trifluoride-methanol (BF3/MeOH) and N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA). Solid-phase microextraction of volatiles originating from S1, S2, Merichem NAs and an AEO mixture led to the identification of 54, 56, 40 and 4 compounds, respectively. The compounds identified in the mixtures included aliphatic and cyclic hydrocarbons, carboxylic acids, alkyl-benzenes, phenols, naphthalene and alkyl-naphthalene, and decalin compounds. To determine the chemical nature of the toxic compounds in NA mixtures, the S2 and AEOs preparations were fractionated using open column chromatography. A non-polar and a polar fraction were obtained from S2. Overall, the toxicity of the polar fraction was not significantly different from whole S2 (p > 0.05). Six fractions of AEOs were obtained, however because of limited material, only the toxicities of F3 and F4 were assessed. The toxicity of F3 was significantly lower than AEOs (p < 0.05) and F4 was not toxic for S. tropicalis (p > 0.05). These results suggest that during fractionation, toxic compounds were lost or that the toxicity of AEOs results from the combined effects of the compounds present in the whole extract. The toxicological dose descriptors, morphometric, transcriptomic and chemical analysis herein presented may contribute to the development of environmental guidelines for NAs and AEOs.

In the present dissertation thesis quality of plum cultivars were investigated in three successive experiments included measurement of ethylene, CO2, ethanol, acetaldehyde, firmness of the fruits and determination of volatile aromatic compounds by SPME/GC/MS Two plum fruit varieties (Stanley and Valjevka) were stored in prepared gas mixtures (FAN: 0,6 % O2 a 1 % CO2, CA: 1 % O2 a 10 % CO2, RA: 21% O2 a 0,03 % CO2) for 70 days. In terms of the 20th, 40th and 60th day followed shelf life for 10 days at 20 °C. Firmness of the skin was different for both varieties and the softening increased in the variety Valjevka. Softening of fruits significantly decreased in FAN and CA. Skin firmness of fruits stored in normal oxygen atmosphere was lower for about 0,59 MPa (Stanley) and 0,67 MPa (Valjevka) at the end of storage. Fruits stored in CA atmosphere were firm, with unbrowning flesh and there was no browning in stem area, too. The results showed that the variety 'Valjevka' has a high capacity (1705 mg/l) to produce ethanol.There was no microbial damage in 'Stanley' stored in CA and FAN at the end of the storage, in RA were 13,19 %. The highest microbial attack was observed in Valjevka stored in RA 41,85 %. Seventy-one volatile compounds were sampled by head space SPME in two plum fruit varieties (Stanley and Valjevka). Using PCA analysis 13 compounds are sufficient for distinguishing ripening of fruits variety Stanley treated by tree storage atmospheres ((Z)-hex-3-en-1-ol, 2-methyl butan-1-ol, (Z)-3-octen-1-ol, 2-heptanol, heptanal, (Z)-3-hexenal, (E)-2-decenal, n-octanal, ethyl acetate, (E)-2-hexenyl acetate, a-terpineol, b-cyclocitral, b-ionone) and 11 compounds for 'Valjevka' (2-octanol, n-octanal, (E)-2-hexenyl acetate, b-cyclocitral, b-ionone, (Z)-3-octen-1-ol, 2-methyl-1-pentanol, (Z)-3-hexenal, n-hexanal, ethyl benzoate a butyl 2-methylbutyrate). The fruits of 13 plum cultivars were analysed at two different stages of maturity: first when they were ready for picking according to conventional commercial criteria, and again after seven days of maturation during shelf life. In the period of over-ripening SSC increased, and no differences were found in relation to the cultivar. The fruits in this period were physiologically in a phase of reduced intensity of respiration, while production of ethylene increased and was associated with the earliness of the cultivar. Cultivars with a short vegetation period produce more ethylene while late-maturing cultivars have a low potential for ethylene production. Based on post-harvest changes in the tested quality factors, the late-ripening plum cultivars (cv.) Jojo, Topend, President, Tophit and Elena have higher storage potential. A high significant negative correlation was detected between levels of skin firmness and ethylene production. 69 of volatiles were determined by GC/MS/SPME. There are eight compounds (oct-1-en-3-ol, p-menth-1-en-4-ol-R, n-hexan-1-ol, n-pentan-1-ol, ethylhexan-1-ol, g-nonanolaktone, g-kaprolaktone and g-oktalaktone) which taken together can be used to distinguished the two different stages of maturity. The fruits of cv. 'Tophit' were untreated or treated with 1-MCP for 24 h at 20 °C and then kept at 1 °C for 50 days in the atmosphere CA (2 % O2 a 7 % CO2) and RA. Plums were evaluated after 10, 30, 50 days of storage at 1 °C followed by shelf life storage for 7 days. The effect of cold and 1-MCP treatment resulted in significant inhibition of ethylene production, respiration rate and retention of flesh firmness after transfer to room temperature. Sixty-four volatile compounds were sampled by head space SPME and identified by GC-MS, from which (E)-2-hexenal, (Z)-hex-3-en-1-ol, butyl-2-methylbutyrate and limonen were significant.

This thesis describes some new methods for analysis oforganic trace components from air and water by gaschromatography. The work is particularly focused on thedevelopment of new technologies for analyte enrichment, usingsorbent-based concepts. Short lengths of open tubular columnswere examined for their potential use as denuders.Polydimethylsiloxane-based stationary phases as well as anadsorbent-based column were evaluated in an equilibrium mode oftrapping. For the analytes selected, detection levels in theppb range were obtained (Paper I). A new, fully automated set-up for analysis of organic tracecomponents in aqueous samples has been developed (Paper II).The work combines specific advantages of the solid phase microextraction (SPME) technology and stir bar sorptive extractionconcept. Ultra trace components, down to 0.1 ppt could bedetected. Finally a simple method for preparation a new type ofultra thick film open tubular trap is described (Paper III).The traps are characterized by an irregular coating, and it wasdemonstrated that the performance characteristics of thesetraps were practically as good as of traps with a smooth,regular coating. The technology can be utilized in many areas,e.g. environmental monitoring, process analysis and otherfields dealing with analysis of trace organic volatiles ingaseous samples. <b>Keywords:</b>Organic trace components, volatiles, denuders,sorbent trapping, thick film trapping, open tubular traps,SPME, automation, water analysis, gas analysis, environmentalanalysis. / NR 20140805

NR 20140805

Synthetic fragrances are artificially synthetised organic compounds which are used as fragrant substances in assorted personal care products, perfumes, cosmetics, soaps, detergents, cleansing articles, etc. So-called musk compounds creates significant group of synthetic fragrances which are distinguished by specific fragrance reminiscent of musk. Recently great attention is devoted to musk compounds because they were proved in different units of environment. The aim of diploma thesis was determination of selected linear musk compounds (arocet, aroflorone, linalool 925, lilial, isoamyl salicylate) in real samples of waste water in the influent and effluent from the sewage treatment plant Brno-Modřice. At first optimization of selected method was performed and then this method was used for own determination. Analytes were extracted by solid phase microextraction (SPME) from sample. Method of gas chromatography with mass spectrometry was used for own analysis. The results were used for evaluation of efficiency of removing linear musk compounds from waste water.

The ultimate goal of this research is to develop an efficient, reproducible and low cost method for analysis of VOCs in complex mixtures such as those in exhaled breath and in headspace of fungi cultures. In Chapter I; analytical methods for volatile biomarkers identification is reviewed In Chapter II, active SPME GCMS was employed to analyze VOCs in the breath of a single healthy male and a single female. The goal was to determine the extent of intra-individual variations in the VOC profiles. In Chapter III, a preliminary study was carried out in a greenhouse to determine the pathogenicity of different isolates of M. phaseolina on soybeans. This will allow, in future studies, the matching of VOC profiles of different isolates of M. phaseolina with their relative pathogenicity. This is a key step towards the development of an early warning system for the detection of pathogenic M. phaseolina fungus contaminations.