Geosmin and 2-methylisoborneol are naturally occurring compounds that are often respon sible for the off-flavor in fish. These compounds, while not causing adverse health effects, still create a musty taste in fish which leads to customer dissatisfaction and distrust in the aquaculture industry. The current method for extracting these compounds from fish involves microwave distillation and then SPME using GC/MS. Microwave distillation does come with challenges as the lack of uniformity of heat can lead to reproducibility issues . There are also scaling issues and potential safety hazards with microwave distillation. Thus, the focus in the development of alternative extraction methods was to remove microwave distillate ion from consideration.
To eliminate microwave distillation in the extraction procedure several solvents were tested, and organic solvents were promising in extracting 2-methylisoborneol and inorganic solvents wer e adequate in extracting Geosmin . Other factors that were considered were different extraction parameters that affect semi-volatile compounds including temperature and length of time in which the sample was exposed to the fiber.
A main challenge has been to obtain sufficient recovery without co-eluting interfering compounds or destroying the compound of interest. 5 mg/kg to 200 mg/kg range of samples were tested for 2-methylisoborneol with acceptable recoveries.
This is currently a work in progress with the method development but are confident that microwave distillation will not be required in extraction of these off-flavor compounds in fish tissue.