Musty odor in chronically off-flavored channel catfish: Isolation of 2-methylenebornane and 2-methyl-2-bornene

Abstract

Chronically off-flavored fish from six commercial channel catfish ponds were sampled during October-December for volatile compounds. Two compounds were consistently isolated from these fish at greater than 0.1 ppm concentrations. The compounds were identified as 2-methylenebornane (1) and 2-methyl-2-bornene (2). They were present both with (one pond) and without (five ponds) detectable (2 ppb) concentrations of the known muddy odor producing compound 2-methylisoborneol (MIB). The mass spectra of the compounds isolated from fish tissue are reported and are identical with those of reference standards of 1 and 2. The dehydration products of MIB, 1 and 2, both impart a musty odor and are believed to be the cause of off-flavor in these instances. © 1988, American Chemical Society. All rights reserved.