Proximate Composition and Collagen Concentration of Processing Residue of Channel Catfish

Residues—including heads, skin, viscera, frames, and trimmings—from the channel catfish Ictalurus punctatus processing industry have generally been made into catfish meal and catfish oil that are used in animal feeds. There may be more efficient uses for these materials, such as producing collagen and other products. A study was conducted to determine the percentages of each component of the processing residue relative to whole fish weight and their crude protein, crude fat, moisture, ash, and collagen concentrations. Of a market-size channel catfish, the head accounted for 24% of the whole weight, the frame 13.6%, the viscera 10.8%, the skin 4.7%, and the trimmings 3.7%. These processing residues represent a total of 56.8% of the total fish weight. The highest crude protein and collagen concentrations were found in the skin (protein, 19.9% of wet tissue and 82.1% of dry matter; collagen, 14.2% of wet tissue and 58.7% of dry matter). The viscera had the highest fat level (32.7% of wet tissue and ...