The development of the metabolic syndrome (MetS) and cardiovascular diseases have been suggested to be influenced more by the quality than the amount of dietary fat. The FA composition of serum lipids may be used as biomarkers of dietary fat quality. FAs can, however, also be endogenously synthesized by lipogenic enzymes such as elongases and desaturases. Three desaturases are important in humans: Stearoyl-CoA-desaturase (SCD), ∆6-desaturase (D6D) and ∆5-desaturase (D5D) and surrogate measures of desaturase activities can be estimated as product-to-precursor FA ratios. In this thesis, we demonstrated that high SCD, D6D and low D5D estimated activities predicted MetS 20 years later, as well as cardiovascular and total mortality during a maximum of 33.7 years. The relation between D5D and MetS was independent of lifestyle and BMI, while the relation between SCD, D6D and MetS was confounded by BMI. Serum proportions of palmitic (16:0), palmitoleic (16:1) and dihomo-γ-linoleic acids were higher and the serum proportion of linoleic acid (LA) lower at baseline in those individuals who developed MetS. Further, LA was inversely related to mortality, while palmitic, palmitoleic and dihomo-γ-linoleic acids were directly associated with mortality. We also demonstrated that a diet rich in saturated fat “induced” a similar serum FA pattern (including estimated desaturase activities) that was associated with MetS, cardiovascular disease and mortality. We also propose that the SCD ratio [16:1/16:0] might be a novel and useful marker of dietary saturated fat, at least in Western high-fat diets. Finally, genetic variations in the human SCD1 gene were linked to obesity and insulin sensitivity, results that agree with data in SCD1 deficient mice. This thesis suggests that dietary fat quality and endogenous desaturation may play a role in the development of metabolic and cardiovascular diseases and the results support current dietary guidelines.

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Genotypes of rapeseeds producing yellow seeds were not found in nature. Breeders yellow-seeded rapeseeds have been developed applying different combinations of interspecific crosses. In the Laboratory of Genetics-Biotechnology at the Lithuanian Agricultural University, yellow-seeded spring rapeseeds were developed for the first time without interspecific crosses (Burbulis, 2001). All cultivars of yellow-seeded rapeseed have one essential drawback – unblocking of pigmentation takes place in other generations and seeds of different colours (yellowish brown, brown or black) are formed. Breeders, working with the cultivars of yellow-seeded rapeseed, admit that environmental temperature is one of the factors limiting the manifestation of the trait.

This thesis deals with the issues of the plant-growth regulators in winter rapeseed. The main part of the thesis is publishing a 2-years-old results of the year 2013/14 and 2014/15, which have been obtained from the small-plot experiments realized on the experimental land of the Faculty of Agriculture of The University of South Bohemia. Three kinds of varieties in a reduced and optimal seed quantity were included in these experiments: line (Remmy), hybrid (H906699) and variety PX 104. The optimal seed quantity was 50 seeds per square meter for a hybrid and PX 104 varieties and 60 seeds per square meter for a line variety. Reduced seed quantity was 33 seeds per square meter for the hybrid and PX 104 varieties and 40 seeds per square meter for the line variety. Three types of applications of the azole preparations were tested for each variety and seed quantity: the first control, the second - treatment in the autumn, the third option - treatments in the autumn and spring. All variants were realized in four repetitions. During the experiments it was observed the influence on the yield of seeds, weight of thousand seeds, percentage of oil, number of plants per square meter and content of the nitrogen compounds in the rapeseed meal. The highest increase of the yield (amounting to 0,94 t/ha) was recorded in 2014 in the variant of a hybrid variety with a density of 33 plants per square meter with autumn and spring application of growth regulators (control 6,82 t/ha, autumn + spring treatment by plant growth regulators - 7,76 t/ha). Similar results were achieved in 2015. In conclusion, it may be said that azole preparations achieve the best results in sparse stands of winter rapeseed.

Ce travail de thèse concerne l'étude et l'évaluation de l'extraction et de la séparation de molécules d'intérêt à partir des résidus de colza. L'impact des différents traitements (broyage, champs électriques pulsés, décharges électriques de hautes tensions et ultrasons) sur l'amélioration de l'extraction des polyphénols et des protéines à partir des tiges de colza a été comparé. Ces traitements permettent d'endommager les membranes et/ou parois cellulaires de manière mécanique, électrique ou acoustique, facilitant ainsi la libération des composés intracellulaires vers le milieu extérieur. La cinétique d'extraction, le rendement en polyphenols totaux et en protéines et la consommation énergétique sont principalement étudiés. De plus, l'efficacité des traitements étudiés pour l'extraction des polyphénols et protéines, en fonction du degré de maturité de la plante a été étudiée. Les méthodes testées pour la séparation des extractibles (polyphénols et protéines) concernent la coagulation, la filtration membranaire ainsi que le couplage de ces deux méthodes afin de réduire la consommation de solvants organiques et la rétention des polyphénols au cours de séparation. La séparation des extractibles a été évaluée par le biais de l'analyse de pureté et du taux de rétention. Enfin, des effets positifs du traitement électrique sur l'étape de séparation des extractibles tels que l'augmentation du flux du perméat et la diminution du colmatage ont été remarqués. / This thesis work concerns the study and the evaluation of the extraction and the separation of valuable compounds from rapeseed residues. The impact of different treatments (grinding, pulsed electric fields, high voltage electrical discharges and ultrasound) on the enhancement of the extraction of polyphenols and proteins from rapeseed stems was compared. These treatments can damage cell membranes and 1 or cell walls mechanically, electrically or acoustically, thus facilitating the release of intracellular compounds to the surroundings. The extraction kinetics, yield of total polyphenols and proteins and energy consumption were mainly studied. In addition, influences of plant maturity on the efficiency of studied treatments for the extraction of polyphenols and proteins have been studied. The methods tested for the separation of extractives (polyphenols and proteins) include coagulation, membrane filtration and the combination of these two methods in order to reduce the consumption of organic solvents and the retention ofpolyphenols during separation. The separation of extractives was evaluated by means of analysis of purity and relative removal. Finally, positive effects of electrical treatment on the extractive separation step such as the increase ofpermeate flux and the decrease of membrane fouling have been observed.

his thesis deal with the processing of used vegetable oil. Its recycling and power generation in the cogeneration unit. Economic and energy balance process. Proposal for a heat exchanger for heating vegetable oil. Physical properties of rapeseed oil.