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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Srovnání méně známých druhů ovoce z hlediska obsahu vitaminu C / Comparison of vitamin C content between less known kinds of fruit

Mařáková, Veronika January 2010 (has links)
This thesis deals with the determination of vitamin C in different varieties of cornelian cherry (Cornus mas) and mountain ash (Sorbus aucuparia). The theoretical part describes the botanical characteristics of both plants, the extension in the CZ and in the world, methods of reproduction, the content of meaningful health substances and the importance of both plants in food-processing industry. Attention is paid to vitamin C, which is in their fruits in high quantity. Conclusion of the theoretical part discusses various methods of determination of vitamin C. The aim of the experimental part was to comparison of the vitamin C content in different varieties cornelian cherry and mountain ash. The chosen method for the determination of vitamin C by high performance liquid chromatography (HPLC) with UV detection was first tested on standards. Selected validation parameters of this method was then determined. Validated method was used to determine the content of vitamin C in nine varieties cornelian cherry and six varieties of the mountain ash. For comparison were also tested some samples of the determination of total vitamin C after reducing dehydroascorbic acid by using dithiothreitol (DTT).
2

Stanovení vybraných nutričních faktorů v některých druzích minoritního ovoce / Vitamin C

Juráňová, Jana January 2013 (has links)
The theme of this diploma thesis is an assessment of given nutritional parameters in selected kinds of lesser known fruits, specifically 10 varieties of sea buckthorn (Hippophae rhamnoides L.), 12 varieties of cornelian cherry (Cornus mas L.) and 6 varieties of blue honeysuckle (Lonicera caerulea var. kamtschatica). Harvests of two consecutive years (2011 and 2012) were analyzed in the case of blue honeysuckle. The theoretical part was focused on historical, morphological, taxonomic and nutritional aspects of individual plants and food or pharmaceutical utilization. The considerable part of the thesis is devoted to the characterization and the possibilities of determining the contained substances, namely ascorbic acid and polyphenolic compounds, especially anthocyanins. The content of the experimental part was a description of the methods and the results of the analysis of total solids, titratable acidity, total phenolics, total anthocyanins and ascorbic acid in fruits of the selected varieties of the above mentioned fruit species. Based on the measured results, the different varieties of fruits were compared to each other and evaluated.
3

Stanovení vybraných prvků v netradičních druzích ovoce / Determination of selected metals in unconventional fruit species

Křížová, Soňa January 2011 (has links)
The aim of this diploma thesis is determination of selected metals in unconventional fruit species, specifically in cornelian cherry (Cornus mas), sea buckthorn (Hippophae rhamnoides) and medlar (Mespilus germanica).There is informationabout 16 analysed metals – As, B, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sn, Pb, V, Zn. There are described analytical techniques for elemental analysis and methods for destruction biological material. Samples for analysis are prepared by using microwave mineralization and ICP-MS for detection. This is described in the experimental part of the diploma thesis. Analysis confirmed that unconventional fruits are rich sources of trace elements.
4

Zhodnocení fyzikálních a chemických parametrů plodů dosud méně využívaných druhů drobného ovoce a návrh nového nealkoholického nápoje z tohoto ovoce / Evaluation of Physical and Chemical Parameters of Still Less Exploited Species of Small Fruit and Proposal of a New Soft Drink from this Fruit

Cetkovská, Jitka January 2016 (has links)
This thesis deals with still less expolited species of small fruit, evaluation of its physical and chemical parameters and proposal of a new soft drink from one of the studied species of furit. Firstly, for the characterisation of basic nutrition parameters (dry matter, content of organic acids and saccharides) and biologicaly active substances (vitamin C, anthocyanins and phenolic compounds) suitable titration, spectrophotometric, chromatographic and electrophoretic methods were chosen, optimized and validated. The sample preparation procedure was optimized as well. For three years (2010–2012) the content of listed parameters was monitored in some cultivars of five species of small fruit: in seven cultivars of sea buckthorn, in ten cultivars of cornelian cherry, in twelve cultivars of rowanberry, in two cultivars of chokeberry and in seventeen cultivars of elderberry. By means of Duncan’s test, analysis of principal components (PCA) and cluster analysis (CLU) the main differences between studied cultivars were observed mainly in sea buckthorn and rowanberry, where single cultivars were easily distinguishable from others on the basis of genetic origin. On the basis of comparison of determined parameters in studied species of fruit and with collaboration with fruit processing company the suitable species of fruit for commercial utilization was chosen – elderberry, as a important source of anthocyanins and phenolic compounds. A new soft drink as a proposal of utilization of this fruit was created – fruit juice or nectar with portion of elderberry juice. Mixed juices and nectars with various composition were prepared from elderberry and grape juice and the sensory analysis of these drinks was performed. The best evaluated were 100% fruit juices prepared with 30–50% portion of elderberry juice. The composition was jurally protected. On the basis of this protection the product consisted from 100% fruit juice with 10% of elderberry component mixed with apple and grape juice was introduced to the market by the fruit processing company.
5

Reinvestigating the Wreck of the Sixteenth Century Portuguese Galleon São João: A Historical Archaeological Perspective

Burger, Elizabeth 10 September 2004 (has links)
The Portuguese galleon, the São João, is one of the greatest enigmas in South African maritime history, not only because so little is known about its cargo, passengers and crew, but also because the location of the wreck has puzzled researchers from the early 20th century until the present. The aim of the Port Edward Project 2001-2003 was to assess both documentary and physical material pertaining to the wreck, to throw more light on the location of the wreck site and survivor camp because this ship is an important part of South Africa’s maritime history as it was the first cargo ship wrecked along the country’s coastline. Many researchers believe it was one of the most richly laden ships to have left India since it was discovered. To begin with all available sources containing reference to the São João and the events surrounding its wrecking were investigated. This established a historical archaeological standard for dating and identification of Portuguese shipwrecks along the South African coast. A chronological examination of the extent of documentary sources resulted in an archaeological underwater and land survey in the area where the greatest concentrations of artefacts are still found today. This geographic area was within a defined zone within the municipal area of Port Shepston. Investigations were limited to a stretch of coast and adjacent inland area between the town of Port Edward, more specifically Tragedy Hill, and the Kuboboyi River. The archaeological material investigated: includes: Chinese porcelain shards, cowrie shells, cornelian beads, pepper and cannons. To prevent reiterating previous investigator’s research a survey was conducted to determine what scientific research has been done on the archaeological material. The actual location of the campsite has not been indisputably determined. It became evident that some research has been done to identify this important site but always only up to a certain point where some uncertainty still remains. This uncertainty is the result of certain factors. Firstly, Tim Maggs only positively identified the wreck site in the early 1980’s. Secondly, great amounts of agricultural activity have been reported in the area and thirdly the survivors only camped for twelve days, which limits the possibility of finding any material. In order to assist in locating this elusive site, the descriptions and details of other Portuguese campsites were investigated. From this it was possible to construct a virtual picture of the survivor camp by comparing the survivor’s account and the known characteristics of Portuguese survivor camps with the artefacts found and geography of the Port Edward area. The chronological examination of documentary sources, the comparison of other Portuguese survivor campsites, the artefacts found in Port Edward and the geography of the area led to the following conclusions: it can be said with a reasonable amount of certainty that the site in Port Edward is that of the São João. A site which demonstrates Portuguese campsite characteristics, where great concentrations of pepper have been found, was identified. It has been established that the partnership with historical documentation and archaeology gives this project the option of taking the investigations further. The virtual scenario assists in reducing the possibilities and refining the focus as opposed to merely terminating the search. It is recommended that specialized equipment be used for future underwater research since the sea conditions are harsh and dangerous. Tough the possible location of the survivor camp was established further excavations might reveal more about the construction of the camp. / Dissertation (MA (cultural history))--University of Pretoria, 2005. / Historical and Heritage Studies / unrestricted

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