Submitted to: Oklahoma Agriculture Experiment Station Departmental Publication
Publication Type: Experiment Station
Publication Acceptance Date: 3/18/2006
Publication Date: 1/15/2006
Citation: Nabors, R.L., Kleinholz, C.W., Schrader, K., Mireles-Dewitt, C.A. 2006. POST-HARVEST REMEDIATION OF OFF-ODOR AND FLAVOR CATFISH (ICTALURUS PUNCTATUS) FILLETS USING ACID SOLUBILIZATION ISOELECTRIC PRECIPITATION. Oklahoma Agriculture Experiment Station Departmental Publication. 2005 Animal Science Research Report:Oklahoma State University. Interpretive Summary: Certain types of blue-green algae that grow in catfish aquaculture ponds can produce musty-odor compounds that cause off-flavor in farm-raised catfish. Such off-flavor problems result in large economic losses to the catfish aquaculture industry. A post-harvest method was developed that uses low acid conditions to help reduce the levels of the musty off-flavor compounds in catfish fillets.
Technical Abstract: Many catfish producers are burdened with the chronic management problem of producing off-odor/flavor catfish. Off-odor/flavor catfish results from two compounds, 2-methylisoborneol (MIB) and geosmin, that can reside in the water in which catfish are raised. The resulting off-odors/flavors decrease profit margins for producers because processing must be delayed until the off-odor/flavor is absent, or the off-odor/flavor product is processed as a less valuable by-product such as fish meal. The objective of this study was to apply a post-harvest process to catfish fillets that solubilizes and then recovers protein using low acid conditions (Acid-SIP) and evaluate its effectiveness at eliminating or reducing the off-odors and flavors associated with catfish fillets. Data indicated there was no statistically significant reduction (P>0.05) in geosmin and MIB concentrations between Acid-SIP samples and non Acid-SIP samples. However, data does indicate that geosmin and MIB spiked catfish that were subsequently processed using Acid-SIP tended to have lower concentrations of the off-odor/flavor compounds, with the only exception to this trend being cooked samples of the geosmin spiked catfish. Fat content was significantly reduced in all raw Acid-SIP samples while protein and ash contents did not differ. Data indicated the Acid-SIP process produced a low fat protein product with strong gel characteristics. Results showed the process has the capability to lower off-odor/flavor compounds, although further research is needed to refine the process and prove its efficacy.