Optimizing enzymatic hydrolysis for feed production from catfish by-products

Introduction. The fisheries industry generates large amounts of fish by-products. Their utilization is one of the relative tasks for fish manufacturers. Hydrolysate from fish by-products is regarded as a valuable bioactive protein source for feed production. In this study, we aimed to optimize hydrolysis conditions for the industrial by-products of catfish. Study objects and methods. We studied the by-products of industrially processed Pangasius hypophthalmus fillet using biochemical methods to find the optimum hydrolysis conditions (enzyme type, enzyme/substrate ratio, temperature, water amount, and time). Then we built a regression model and verified it experimentally. Results and discussion. According to the Box-Behnken design model, the optimum hydrolysis conditions were determined as 10% of water, 0.48% of SEB-Neutral PL enzyme, 57°C temperature, and 6 h duration. We found no significant differences between the modelled and the verified experimental values. The resulting hydrolysate was rich in nitrogen from amino acids, and its other parameters complied with the current national standards. The microbal and sensory attribites satisfied quality requirements as an animal feed supplement. Conclusion. The study results are commercially applicable in feed production, providing a solution for the fisheries industry in byproduct treatment.