DSpace Repository

Profiling and modelling of triglycerides and volatile compounds in SA hake (merluccius capensis and merluccius paradoxus)

Show simple item record

dc.contributor.advisor Venter, P.
dc.contributor.advisor Lues, J.F.R.
dc.contributor.advisor Ivanov, I.
dc.contributor.advisor Luwes, N.
dc.contributor.author Swanepoel, Hanita
dc.contributor.other Central University of Technology, Free State. School of Agriculture and Environmental Sciences
dc.date.accessioned 2014-10-17T21:00:55Z
dc.date.available 2014-10-17T21:00:55Z
dc.date.issued 2011
dc.identifier.uri http://hdl.handle.net/11462/156
dc.description Thesis (D. Tech. Environmental health) -- Central University of technology, Free State, 2011 en_US
dc.description.abstract Apart from being the primary food source of many cultures around the world, fish contains notable amounts of essential fatty acids that are required by the human body, thus making fish a vital part of the human diet. In South Africa Cape hake is a well-known and highly consumed local fish species, which is transported from coastal areas countrywide where the fresh fish are displayed on ice in various retail stores. Fish is known to be highly susceptible to spoilage and, as a result, the maintenance of the cold-chain in related products is of particular importance. Additionally, recent trends showing a decline in natural fish resources have instigated growing concerns about the sustainability and optimal utilisation of fish as a food source. Against this backdrop, this study aimed at determining the influence of storage parameters on selected triglycerides and their possible metabolic pathways. Also applying prediction modelling of fatty acids and volatiles as instruments to assess exposure of Cape hake fillets to excessive microbial contamination and, in effect, be indicative of the environmental parameters (for example temperature) that may influence such contamination. Randomly selected juvenile hakes were filleted and stored under various simulated retail storage conditions, under either controlled or uncontrolled environmental conditions. For each hake filleted, one fillet was inoculated with an increased load of autochthonous microbiota, and the corresponding fillet was kept at similar temperature conditions. All fillets were monitored over a ten day period, during which fatty acid and volatile samples were collected and analysed. From the resulting triglycerides a selection of fatty acids were profiled and their possible metabolic pathways investigated. Fish maturity, the distribution of the fatty acids and the implication thereof in the nutritional value were also assessed. Conventional chemometric methods utilising mathematical expressions were subsequently utilised in order to predict contamination and whether the cold chain was sustained, while an artificial neural network (ANNs) were designed to predict excessive microbial contamination in the fillets. The results showed that the nutritional value of fish differs notably with its maturity and size. Mathematical equations were furthermore found to be effective assessment instruments to indicate the percentage differences in storage temperature, as well as consequent microbial influences. Thus, this approach may introduce mathematical prediction modelling as a promising mechanism to assess Cape hake spoilage. An artificial neural network (ANN) was successfully designed, that succeeded in distinguishing between Cape hake fillets displayed and stored on ice that have been exposed to excessive contamination and those that have not been exposed. In the latter case, the selected variable was a fatty acid, hexadecanoic acid, used as biochemical indicator. This modulating approach may provide a platform for future shelf-life studies on related muscle tissue. Ultimately, the study endeavoured to add to the body of knowledge regarding the biochemical and microbiological changes related to Cape hake storage, the prediction thereof via contemporary methods and contributing to the safety and effective utilization of this unique and declining South African nutritional resource. en_US
dc.format.extent 2 029 051 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en_US
dc.publisher Bloemfontein : Central University of Technology, Free State
dc.subject Central University of Technology, Free State - Dissertations en_US
dc.subject Microbial contamination en_US
dc.subject Fishery products - Storage en_US
dc.subject Fishery products - Spoilage en_US
dc.subject Fish as food - Analysis en_US
dc.subject Fish as food - Contamination en_US
dc.subject Dissertations, academic - South Africa - Bloemfontein en_US
dc.title Profiling and modelling of triglycerides and volatile compounds in SA hake (merluccius capensis and merluccius paradoxus) en_US
dc.type Thesis en_US
dc.rights.holder Central University of Technology, Free State

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search DSpace


My Account