This master thesis deals with the assessment of aroma active compounds in fruits of currant (Ribes spp.). The theoretical part was focused on basic characteristics and chemical composition of currants, as well as the basic principles of techniques used: solid phase micro extraction (SPME), gas chromatography (GC) and sensory analysis. The main aim of the experimental part was to determine aroma active compounds in currants using SPME-GC-FID method. The profile and scale tests were used for assessment of sensory quality and tastiness of fruits. In total 18 varieties, among them 6 white, 6 red and 6 black currants, were evaluated. Fifty aroma active compounds were identified including 21 alcohols, 10 aldehydes, 2 acids, 8 ketones and 9 esters. The results were statistically evaluated using principal component analysis (PCA) to investigate the influence of single compounds on sensory quality of fruits.

Carotenoids are natural pigments occurring in plants and many microorganisms, such as algae, yeast and bacteria. They represent the most common group of antioxidants with significant biological effect. Lipids are an essential component of all living organisms. They are the source and the reservoir of energy for organisms, which can also be used in the petrochemical industry for the production of biofuels. This thesis deals with the production properties of carotenoids and lipids by selected strains of yeasts, algae, and canobacteria, in order to apply the acquired knowledge and find cheap suitable alternatives for microbial biotechnological production of these metabolites using waste substrates. Carotenoids, coenzyme Q, and ergosterol in cells were determined by liquid chromatography. The lipid content and fatty acid profile was analyzed by gas chromatography. Cell morphology and localization of selected metabolites were analyzed by fluorescence lifetime imaging microscopy. In this work yeast genera Sporobolomyces, Cystofilobasidium and Rhodotorula were used. As the representatives of the algae and cyanobacteria strains of Desmodesmus, Cyanothece, Chlamydomonas, Synechoccocus and Chlorella strains were studied. In the overall comparison, the yeast strains were more productive than algae and cyanobacteria. The highest carotenoid production was found in S. pararoseus, C. capitatum and R. mucilaginosa cells, while the highest lipid yield was observed in strains of C. infirmominiatum and S. metaroseus.

The diploma thesis deals with the monitoring of oxidative stability of products, oils and butter, from nut fruits. The theoretical part concentrates on the topic of nut fruits, their properties, compositions which are closely related to the effects on the human health and the possibilities of technological processing. The lipid storage process, especially the most frequently occurring autooxidation reactions are described, followed by experimental part of the thesis. The changes in coconut, walnut, peanut oils and peanut butter samples are monitored during storage at 4 ° C and 20 ° C by determining the acid value, the peroxide value and the fatty acid composition by the GC-FID method. The lowest oxidation stability showed walnut oil due to the highest content of unstable polyunsaturated fatty acids – up to 88,7 %. During storage at 20 ° C there was a statistically significant increase in the content of primary oxidation products, determined as peroxide value PV = 2,55 ± 0,12 µgROOHg-1. An increase was also observed in samples of peanut butter, but it was mainly due to higher water activity, which is important for chemical reactions. The durability of this product after opening mentioned on the product label correlates with their low stability

The diploma thesis will be focuses on the isolation of fragrances of natural origin by steam vapor distillation, ultrasonic extraction, microwave extraction and pressure solvent extraction. The extracts were characterized by GCxGC/TOF-MS. To study the surface structure of the leaf by SEM, a sample of the medulla medical was selected. Photos were taken before and after extraction.

“Green” explosives are an important sub-family of explosives due to the banning of explosives based on heavy metals, such as lead azide and lead styphnate, according to the REACH list. A substitute to lead azide is potassium 4,6-dinitrobenzofuroxane (KDNBF) which is an alternative “green” explosive. Hence there is an upcoming need for analytical and quality control protocols for KDNBF. In this report is HPLC-UV/VIS, GC-FID and potentiometric titration evaluated for their suitability as methods for testing of KDNBF. The results implies that KDNBF can be analyzed by GC-FID, when dissolved in DMSO and caffeine is used as internal standard. To analyze KDNBF by HPLC-UV/VIS was isocratic mode used together with a porous graphitic carbon (PGC) (Hypercarb ®) column. However, degradation of the analyte was severe and quantitative results were not obtained. Potentiometric titration indicated that KDNBF equilibrate with four hydrogen ions during titration, instead of the one to one ratio with potassium and hydrogen ion, as in previously proposed theory. Despite this and with careful titration is potentiometric titration and GC-FID analysis combined suitable as a quality control protocol for KDNBF.

Thesis (DPhil (Chemistry))--Cape Peninsula University of Technology, 2019 / Occurrence of polycyclic aromatic hydrocarbons (PAHs) in freshwater systems may aggravate the water crisis currently being experienced in the Western Cape province of South Africa. However, there is dearth of data on the levels of PAHs, necessary for effective assessment of water quality as well as remediation strategies. This study therefore assessed levels of PAHs in two important freshwater systems in the Western Cape Province, South Africa. The potential of grape leaf litter for PAH abatement was also investigated. A solid-phase extraction - gas chromatography - flame ionisation detection (SPE-GC-FID) method was developed to simultaneously determine the 16 United States Environmental Protection Agency (US EPA) priority PAHs in environmental samples. Levels of 16 US EPA priority PAHs were assessed in water, sediment and plants from seven selected sites on the Diep and Plankenburg Rivers. Seasonal variations of some water quality parameters and PAHs levels in water and sediment samples were determined from the selected sites. Activated carbons produced from Vitis vinifera (grape) leaf litter were utilised for PAH-remediation. The SPE-GC-FID method developed for the 16 US EPA priority PAHs determination gave acceptable linearity (R2 > 0.999). Instrument detection limits ranged between 0.02 and 0.04 µg/mL and instrument quantification limits of between 0.06 and 0.13 µg/mL. Recovery studies were also acceptable (70.35 - 100.83%) with the exception of naphthalene that had lower recoveries. The average ∑16 PAHs detected in water samples at a given site, over a one-year period ranged from 73.90 to187.11 µg/L. The highest PAHs levels were detected in water samples from industrial areas of both rivers; chrysene (Chy) followed by benzo[a]anthracene (BaA) were the most abundant PAHs detected in water samples. Higher PAHs levels were detected in sediment samples relative to water samples; the average ∑16 PAHs detected in sediment samples at a given site, over a one-year period ranged from 6.048 to 39.656 µg/g. PAHs levels were also highest in sediment samples from industrial areas of the two rivers; benzo[b]fluoranthene (BbF) followed by benzo[k]fluoranthene (BkF) were the most abundant PAHs detected in sediment samples. The average ∑16 PAHs detected in plant samples [Phragmites australis (common reed) and Eichhornia crassipes (water hyacinth)] at a given site, ranged between 62.11 and 226.72 µg/g. Highest levels of PAHs were therefore detected in plant samples, suggesting possible bioaccumulation of PAHs in plant tissues. The bioaccumulation of PAHs by the plants also indicates the phytoremediation potential of these plants for PAHs remediation. The levels of PAHs measured in water and sediment samples were subjected to probabilistic risk assessment to predict the possibility of regulatory values being exceeded. The average percentage exceedence of 63.26 and 42.81 were obtained for PAHs in water samples of the Diep and Plankenburg Rivers respectively, while the corresponding average percentage exceedence obtained for sediment samples were 63.71 and 77.20. Vitis vinifera (grape) leaf litter showed enormous prospect as precursor for activated carbon. The yield of activated carbons obtained from grape leaf litter ranged from 44.65 to 58.40% and the Brunauer-Emmett-Teller (BET) surface area of up to 616.60 m2/g was obtained for activated carbons. The estimated adsorption capacities of the ZnCl2 and H3PO4 activated carbons for phenanthrene removal from aqueous solutions were 94.12 and 89.13 mg/g respectively. The environmental samples analysed were heavily contaminated with the 16 US EPA priority PAHs and the probabilistic risk assessment suggested risks of the carcinogenic PAHs at the levels measured in the environment. Vitis vinifera leaf litter, showed enormous potential as renewable precursor for activated carbon production, capable of removing varied contaminants from wastewater.

This paper studies castor oil’s potential as a biodiesel feedstock. Base-catalyzed transesterification batch reactions were conducted at various experimental conditions while measuring the concentration of the reaction components over time. A gas chromatograph with a flame-ionization detector analyzed these samples. A factorial design of experiments was used to determine how conversion was affected by reaction temperature, sodium methoxide concentration, and ratio of methanol to oil. Conversion was maximized (0.9964) at 30 °C, 0.5% catalyst, and 9:1 molar ratio. The concentration data were used to study the reaction kinetics. Modeling the reaction as three equilibria yielded six rate constants. These values indicate that castor oil transesterifies faster than soybean oil. The fuel properties were determined by ASTM D 6751. Viscosity was excessively high, but specifications were met for the remaining tests. Despite the promising yield and kinetics of the reaction, the fuel viscosity limits castor oil’s viability as a biodiesel feedstock.

No description available.

L'évaluation de l'inertie des matières plastiques au contact de denrées alimentaires est régie par le règlement européen N°10/2011. Au Liban, l'absence de législations relatives à l'usage des matières en plastiques a conduit à des emballages non contrôlés au niveau de la production et du stockage, ce qui peut induire un risque sanitaire pour le consommateur. L'objectif de ce travail a été d'apprécier les phénomènes de migration des contaminants du PET vers l'eau. Pour cela, l'analyse de certains migrants potentiels a été initiée tels que des COV et des SV afin de vérifier la conformité de leur teneur par rapport aux LMA dans les règlementations internationales. Le dosage des aldéhydes dans l'eau a été effectué par dérivation avec la 2,4-DNPH, suivie d'une étape de préconcentration sur une cartouche en C18, puis séparation et quantification par HPLC-UV. L'analyse des composés SV a été réalisée par SPME-GC-FID sur une fibre en PDMS/DVB. L'analyse des BTEX et du styrène a été réalisée par HS-Trap-GC-FID. Ces méthodes ont été validées conformément à la norme NF T 90-210 avec des LQ inférieures aux LMA. L'analyse des COV dans l'eau embouteillée et dans le PET a été réalisée par HSTrap- GC-MS. La présence de FA, d'AA, de DEP et des BTEX dans l'eau embouteillée en PET a été confirmée. Il a été mis en évidence que la température et l'exposition solaire influencent la migration des aldéhydes. Les concentrations d'AA trouvées après incubation à 40ºC ne sont pas négligeables et peuvent modifier les propriétés organoleptiques de l'eau. L'analyse du PET montre la présence des hydrocarbures, des aldéhydes, des alcools, et des cétones / The inertness’ value of plastics that are on contact with foodstuffs is governed by the European rule N°10/2011. In Lebanon, the lack of the Rules and Regulations of plastics’ usage led for a non-controlled packing in production as in storage, which will cause a sanitary risk to the consumer and to the population. The purpose of this research was to appreciate the migration’s phenomena of contaminants from the PET to the water. For this, there was an analysis of potential migrants such as VOC and SV to verify their tenor’s conformity relative to the MCL in international regulations. The aldehydes’ dosage in the water was performed by the derivation with the 2,4-DNPH, followed by a concentration on a C18 cartridge, then separation and quantification was done by HPLC-UV. The SV compounds’ analysis was realized by SPME-GC-FID method on a PDMS / DVB fiber. The BTEX and the styrene’s analysis was done by HS-trap-GC-FID method. These methods were validated in accordance with standard NF T 90-210 with a LQ less than the MCL. The volatile compounds in the bottled water and in the PET were analyzed by HS-trap-GC-MS method. The presence of FA, AA, DEP and BTEX in the bottled water with the PET was confirmed. It was highlighted that temperature and sun exposition influence the aldehydes’ migration. The acetaldehyde’s concentration after incubation at 40ºC wasn’t negligible and can modify the water’s organoleptic properties. The PET’s analyze reveals the presence of hydrocarbons, aldehydes, alcohols and ketones

Os extratos vegetais amazônicos para uso em beneficiamento têxtil podem ser uma alternativa sustentável e ecológica em relação às atuais matérias-primas utilizadas pelo mercado. Este estudo teve como objetivo efetuar a caracterização físicoquímica de extratos vegetais amazônicos (óleo-resina de copaíba, óleo de castanha do Brasil, óleo de buriti, manteiga de cacau, manteiga de tucumã e manteiga de cupuaçu), preparar emulsões e realizar aplicações preliminares destas em têxteis. A caracterização físico-química foi realizada através das técnicas instrumentais analíticas de espectroscopia de infravermelho por transformada de Fourrier (FTIR) e cromatografia a gás com detecção por ionização de chama (CG-FID). Além disso, foi realizada a determinação do Equilíbrio Hidrófilo-Lipófilo (EHL) das emulsões preparadas a partir dos extratos estudados; seleção da emulsão mais estável por extrato para aplicação por foulardagem; avaliação da oxidação das emulsões aplicadas sobre o material têxtil em diferentes temperaturas (120 a 200ºC); e avaliação sensorial de toque proporcionado pelas emulsões em comparação a um amaciante de uso industrial. Os principais resultados foram que o óleo de castanha do Brasil e as manteigas de cacau, tucumã e cupuaçu apresentaram resultados próximos nas análises por FTIR; a distribuição graxa por cromatografia a gás mostrou-se útil para a caracterização destes extratos vegetais; os valores de referência de EHL para os extratos analisados foram de 7,51 a 10,72 e estão de acordo com a literatura científica (de 6 a 12); os extratos estudados emulsionados nas condições do estudo não possuem tendência à oxidação por temperatura; as médias globais das análises sensoriais de toque indicam um resultado inferior ao padrão comercial, porém, as manteigas de cacau, cupuaçu e o óleo de castanha do Brasil apresentaram os melhores resultados, com notas entre 2,8 e 2,9 (numa escala de 1 a 5). Assim, nota-se que, os resultados obtidos podem ser utilizados como base para pesquisas futuras no sentido de melhorar as formulações das emulsões para a produção de amaciantes ou outros produtos / The Amazonian plant extracts for use in textile processing can be a sustainable and environmentally friendly alternative to the current raw materials used by the market. This study aimed to make the physicochemical characterization of Amazonian plant extracts (copaiba oleoresin, Brazil nut oil, buriti oil, cocoa butter, tucumã butter and cupuaçu butter), prepare emulsions and perform preliminary applications in textile. The physicochemical characterization was performed by analytical instrumental techniques, such as FTIR spectroscopy and gas chromatography with FID detection (GC-FID). Furthermore, the determination of the Hydrophile-Lipophile Balance (HLB) was performed of the emulsions prepared from the extracts studied; the emulsion more stable for selection extract for application by padding; evaluation of the oxidation of emulsions applied to the textile material at different temperatures (120 to 200C); and sensory evaluation provided by the touch emulsions compared to a industrial softener. The main results were that the Brazil nut oil and cocoa, tucumã and cupuaçu butters showed similar results in the analysis by FTIR; grease distribution by gas chromatography proved to be useful for the characterization of plant extracts; the HLB values for the reference analyzed the extracts were 7.51 to 10.72 are consistent with the literature (6 to 12); the extracts studied emulsified in the study conditions have no tendency to oxidation temperature; the global average of sensory analysis touch indicate somewhat lower than the commercial standard, however, cocoa and cupuaçu butter and Brazil nut oil showed the best results, with grades between 2.8 and 2.9 (on a scale of 1 to 5). Thus, it is noted that the results obtained can be used as the basis for further research in order to improve the formulations of emulsions for the production of fabric softeners or other products