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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

Determination Of Morphine And Total Phenolic Content In Poppy Seed Of Turkish Origin

Gevenkiris, Ali 01 November 2011 (has links) (PDF)
Turkey is important major licid opium poppy (Papaver Somniferum) producer for medicinal and scientific purposes in the world and one of the two traditional producer country. The poppy seeds which are unique part of the opium poppy are used for food purpose. About 25.000 ton/year poppy seeds were produced for food purpose. Recent years morphine content of commercially available poppy seeds were speculated. Some studies have been reported that poppy seeds from different origins contain a wide variation of morphine (2 &ndash / 294) &mu / g/g content. They have been used also different sample preparation method (extraction and derivatization) and different instruments (GC-MS) during analyses. In this study morphine content was determined in Turkish origin which were white, yellow and blue poppy seeds colors by using high pressure liquid chromatography (HPLC). Different sample preparation method (without derivatization) was used. Morphine was eluted from poppy seeds by acidic water through stationary phase activated aluminum oxide. Poppy seed samples were collected from 13 provinces and 35 different sowing fields of Turkey. The determined morphine contents in poppy seeds were ranged between (9.73 to 37.46) &mu / g/g. Any study was not found in the literatures on determination of total phenolic in poppy seed. In this study, the optimum condition for extraction of polyphenols in poppy seeds was determined and then, total phenolic values were obtained in three different colours seeds by spectrophotometric method. At the end of experiments the total phenolic contents in white, yellow and blue colours poppy seed were found to be 4.44, 3.05 and 3.67 mg/g respectively.
2

Ultrasound Assisted Extraction Of Lipids And Antioxidants From Wheat Germ

Melikoglu, Mehmet 01 February 2005 (has links) (PDF)
The aim of this thesis work was to extract lipids and antioxidants from wheat germ using an ultrasonic bath. Alternative solvents: Ethanol, isopropanol and acetone were used for the extraction purposes and for the fat content determination hexane was used. Alternative solvents dissolve wax, phospholipids and some other proteins because of their polar nature which increased the yield. Since waxes and some proteins can be added to the soaps and creams which were made from carrier oils, obtaining these substances together with the oil in the extract was very useful. For isopropanol a linear relation was found between the extract ratio and ultrasonication time. The highest extract ratios were achieved with ethanol. For 30 minutes of ultrasonication 0.10 g extract / g germ was obtained. After the extraction in order to enhance the phase separation between the solid phase (germ and other solids) and the extract phase, combinations of centrifugation, storage in the refrigerator and decantation were tested. The technique involving storage the extracts in the refrigerator for 24 hours and centrifugation at 2800 rpm for 20 minutes gave the second highest yield but the best phase separation. Ethanol extracts from both roasted and nonroasted wheat germs were characterized in terms of their total polyphenol contents. For non roasted wheat germs total polyphenol contents of 200 mg gallic acid / L solution and for roasted wheat germs an average of 170 mg gallic acid / L solution were obtained for 30 minutes of ultrasonic extraction. For nonroasted wheat germs weak but significant linear relations were found between total polyphenol contents of the extracts and ultrasonication time.
3

Evaluation of the antioxidant and anti-diabesity potential of cyclopia maculata using in vitro non-cell based screening models

Matrose, Albertina Neliswa January 2014 (has links)
Masters of Science / The aim of this study was therefore to evaluate the antioxidant and anti-diabesity potential of a hot water extract of C. maculata in non-cell based assays and correlate the activities with phenolic composition. Total antioxidant capacity (TAC) was assessed in terms of free radical scavenging and iron reducing ability. The DPPH, ABTS, ORAC and FRAP assays were employed. Anti-diabesity potential was assessed in terms of the inhibition of the digestive enzymes, α-glucosidase and pancreatic lipase
4

Impact of cocoa (Theobroma cacao L.) fermentation on composition and concentration of polyphenols: Development of fermentation model system and utilization of yeast starter cultures

Lee, Andrew H. 28 September 2017 (has links)
Consumption of cocoa and dark chocolate products has been associated with positive health outcomes including reduced onset of cardiovascular disease, inflammation, diabetes, obesity, and platelet disorders. Cocoa polyphenols, putatively responsible for these beneficial activities, are highly impacted by cocoa variety, agronomic effects and processing history. However, the difference in polyphenol concentration and composition between cocoa products originating from different hybrid clones (selected for high yield) or from different fermentation conditions is not fully understood. Detailed polyphenol characterization including determination of total polyphenol and total procyanidin concentrations, and qualitative and quantitative analysis of (mean) degree of polymerization was conducted. Significant differences in total polyphenol and procyanidin concentrations were observed between five genetic clones grown by the USDA-ARS Cocoa Germplasm Repository located in Mayagüez, Puerto Rico. To facilitate cocoa fermentation research in laboratories distant from cocoa harvesting sites, a laboratory-scale cocoa fermentation model system was developed in this study. This model system used dried, unfermented, cocoa beans and simulated pulp medium as the starting material. The model system supported growth of the essential succession of cocoa fermenting microorganisms and generated similar chemical changes to those observed in on-farm cocoa fermentation. Using this model system, the impact of inoculation with proprietary yeast strains Saccharomyces cerevisiae Lev F and Saccharomyces cerevisiae Lev B on cocoa polyphenol concentration and composition was evaluated. Inoculation with both yeast strains resulted in increased fermentation rate and Lev B inoculation resulted in higher total polyphenol and procyandin contents at the end of fermentation. Overall, the present work addressed the influence of cocoa variety selection and fermentation process conditions on the composition and concentration of polyphenols. These findings will contribute to continued efforts to develop cocoa products with optimized bioactivity and maximum disease preventative effects. / PHD / Annual worldwide cocoa production exceeds four million tons and the cocoa market impacts not only cocoa growing regions, but also countries producing cocoa products. Consumption of cocoa and dark chocolate products has been associated with positive health outcomes including reduced onset of cardiovascular disease, inflammation, diabetes, obesity, and platelet disorders. Cocoa polyphenols, compounds increasingly associated with health benefits, are highly impacted by the variety and processing history of cocoa. However, the extent to which cocoa genetic variety and processing conditions impact polyphenol concentration and composition is not fully understood. Polyphenol characterization was conducted for five genetic varieties sourced from the USDA cocoa germplasm repository located in Mayagüez, Puerto Rico and it was found that genetic variance could contribute to differences in polyphenol concentration. The main focus in this thesis was to develop laboratory cocoa fermentation model system to facilitate cocoa research in laboratories distant from the cocoa growing region. This model system used dried, unfermented cocoa beans and simulated pulp medium as the starting material. The model system was effective in that it supported growth of the essential succession of coca fermenting microorganisms and generated similar chemical changes to those observed in on-farm cocoa fermentation. This model system could be further applied to test the impact of fermentation conditions on cocoa bean quality. The potential for using yeast starter cultures to improve control and consistency of cocoa fermentation was evaluated using the model fermentation system. Yeast inoculation improved fermentation rate, and polyphenol concentration in fermented beans was higher when cocoa fermentation was inoculated with the yeast strain Saccharomyces cerevisiae Lev B. Overall, the present work addressed the influence of cocoa variety selection and fermentation process conditions on the composition and concentration of polyphenols. These findings will contribute to continued efforts to develop cocoa products optimized for maximum health benefits.
5

Nutritional profiling and effects of processing an unripe banana cultivars in Limpopo Province, South Africa

Anyasi, Tonna Ashim 01 February 2016 (has links)
PhD (Agriculture) / Department of Food Science

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