Analysis of 2-Methylisoborneol in Water, Mud, and Channel Catfish (Ictalurus punctatus) from Commercial Culture Ponds in Mississippi

We describe a new method for the isolation of 2-methylisoborneol (MIB) from channel catfish (Ictalurus punctatus) that have been declared "off-flavor" organoleptically. The method involves microwave cooking fish under a nitrogen stream and trapping the condensate at −80 °C. The fish condensate was extracted with hexane which was reduced to 100 μL and analyzed by gas chromatography. Concentrations as low as 5 ng MIB∙g fish−1 were routine detected. A bioconcentration value for MIB in off-flavored fish flesh was 28.1 ± 14.0 (±SD) concentration water/concentration fish. Analysis of off-flavored fish collected at the processing plant consistently showed elevated concentrations of MIB. Geosmin, another compound known to cause flavor and odor problems in fish flesh, was not detected.