Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/18318
During recent years, the natural product chemistry of marine organisms has received much attention as a promising new field of study. In particular, marine algae have proven to be a rich source of structurally diverse bioactive compounds with a high potential value to food, cosmetic, and pharmaceutical industries.
Therefore, the main focus of this study was to investigate how preparation and extraction methods effect the yield and chemical composition of the crude extracts obtained from Icelandic marine macroalgae. Insight from this could then be used to increase the efficiency of production methods and so achieve maximum yields.
As such, the research was conducted in two parts. The former focused on the identification of a suitable site for conversion to organic status, in order to secure a supply of certified organic raw material required during the latter part of this study. Such an area was identified in Stafnes, and an application for organic conversion via Vottunarstofan Tún was accepted in December, 2012.
In the second part of the study, fresh samples of Ascophyllum nodosum, Laminaria digitata and Saccharina latissima, were carefully collected and subjected to the following four types of material preparation: Freezing, air drying, freeze drying and oven drying. Each material type then underwent extraction via the use of a vacuum Soxhlet, using certified organic ethanol (96%, 48% and 0%) and ultra-pure water to produce extract fractions that were subsequently dried.
The following types of analysis were then conducted on both the raw prepared material and the extracts: Proximate composition analysis, elemental analysis and phytochemical analysis.
The results showed that, in almost all cases, the highest constituent contents measured were obtained when they were prepared via freezing. Of the prepared raw material analysed, the highest average values of fat (4.36%) and protein (7.51%) content were obtained from frozen Ascophyllum nodosum. Whereas the highest average carbohydrate content (45.23%) was seen in frozen Saccharina latissima.
The results from the analysis of the extracts showed that the fraction which contained the highest average carbohydrate content (87.17%) was from freeze dried Saccharina latissima, which had been extracted with a low concentration of ethanol (high concentration of ultra-pure water).
The phytochemical analysis of fucoxanthin results revealed that the use of frozen Laminaria digitata material extracted with 96% ethanol, provided the highest yield (1.96 mg/g dry weight of extract).
Finally, the quality control analysis showed that there were no PCBs present (within detection limits) in any of the samples tested, and that the highest concentration of arsenic measured was 4.9 ppm, thereby confirming that the raw material, the extracts and the collection site were all within safe limits of these compounds.
In conclusion, the way the plant material is prepared before extraction can have a significant effect on both the yield and composition of the final crude extracts achieved.
Furthermore, variations in the methods used also play an important role in the effective extraction of specific target compounds of interest.
|Daniel James Coaten Masters Thesis 0712764659.pdf||1.86 MB||Opinn||Heildartexti||Skoða/Opna|