The texture of cooked and raw fillets of both channel (Ictalurus punctatus) and hybrid (female channel x male blue, I. furcatus) catfish were measured by instrumental texture profile analysis (TPA) methods. Catfish from commercial and experimental ponds were used, that included differences in geographical region, harvest season, fish gender, and the type of fillet cold-storage (fresh, frozen, of IQF), with or without polyphosphate treatment.
Comparing baked fillets across all three cold-storage types combined, channel catfish were found to have significantly (p<0.05) higher values for six of the seven texture attributes, firmness, toughness, cohesiveness, chewiness, resilience, and springiness, with only adhesiveness not showing any difference. Channel-hybrid differences, based on each cold-storage type (Table 1), showed fresh fillets to have more than a 60% difference, while frozen had the largest number of significant attributes and IQF having the fewest significant differences. Significant differences between cold-storage types, not based on catfish type, were only seen for cohesiveness, adhesiveness, resilience, and springiness. This indicated the channel-hybrid differences were predominantly based on the firmness, toughness, and chewiness attributes.
Fillet thickness also showed a covariance with most texture attributes, but based on statistical analysis calculations, firmness was significantly different for the full range of thicknesses used in the study, while toughness became significantly different above 11.9 mm fillet thickness (cooked), with 96% of fillets having larger average thicknesses.