30H-4 |
Influence of physical and chemical intervention methods on Geosmin and 2-MIB in channel catfish flesh |
J. L. SILVA, R. A. Bazemore, and T. Kim. Dept. of Food Science & Technology, Mississippi State Univ., PO Box 9805, Mississippi State, MS 39762 Channel catfish is described as having a mild, nutty/sweet flavor. In the warm months, the incidence of two predominant off-flavors, 2-methylisoborneol, MIB and geosmin is over 50%. Their presence adds a noticeable earthy and musty taste in fillets of catfish producing rejection by the consumer. The objective of this project is to explore the effect of different physical and chemical methods on removal of these compounds as measured analytically and sensory. Catfish fillets rated 4 on a 5 point off-flavor score were harvested, frozen individually, and treated after overnight thawing at 4C. Half of each fillet was cut longitudinally and kept for sensory assessment. The other halves were treated as follows: Ozone at 5 ppm was injected (OI) directly in the muscle or indirectly (OC) for 20 min in a chiller tank, and a 1% salt plus 0.1% ascorbic acid (CT) was applied to fillets by tumbling for 20 min. All untreated and treated samples were microwaved on High power for 40 sec and tasted. There was a slight reduction in off-flavor (MIB or geosmin) of ozone-chilled fillets but not injected samples. The CT treatment only obscured off-flavor detection in the tongue by its salt content, but only momentarily. There were no apparent differences in sensory appearance of all treated samples. No sample was rated below a 2 by panelists. The intervention methods after slaughter were not able to successfully eliminate off-flavor in catfish fillets. However, some decrease was noted. A possible combination of treatment may be more effective.
Session 30H, Quality Assurance
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