Fresh catfish (Clarias gariepinus) is highly perishable. This paper aims to investigate the drying characteristics and quality of body-mass dehydrated catfish to determine the effective dehydration parameters for preservation.
Brine concentration (3-9 per cent), brining time (30-90 min) and drying temperature (90-130°C) interacted using the response surface methodology. Preliminary experiments were conducted to select treatments. Moisture content and ratio and drying rate were determined and fitted into five thin-layer drying models; the goodness of fit was evaluated by average grade ranking of the regression parameters. Proximate compositions and microbial load of dehydrated catfish were determined using standard methods.
Treatments with 110°C gave initial higher drying rate (0.034-0.043 kg H2O/kg solid/h) and shorter drying time (20-21 h). Drying occurred at two falling rate periods. Midilli model ranked first in fitting the drying data. It explained up to 99.6-99.7 per cent of the total variations in the independent variables with low values of error terms; RMSE was 0.02131-0.01794 and χ2 was 0.00037-0.00043, indicating good predictive quality. Processing parameters positively and significantly (p < 0.05) influenced the proximate compositions of dehydrated catfish. Treatment: 6 per cent brine, 90 min and 110°C presented the most effective dehydration parameters for quality preservation of body-mass catfish.
The dehydration technique used in this study could enhance nutritive quality and storage stability of body-mass dehydrated catfish that could serve as a useful and convenient tool for commercial application.
Hygienically processed dehydrated catfish of good quality could be used as a source of nutrients to ameliorate malnutrition and reduce post-harvest losses of catfish.
The effective processing parameters established is an important step to harness the high nutrients and economic values embedded in catfish.
