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Comparing the kinetics of the hydrolysis of by-product from channel catfish (Ictalurus punctatus) fillet processing by eight proteases

Tan, Yuqing, Chang, Sam K.C., Meng, Shi
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2019 v.111 pp. 809-820
Ictalurus punctatus, bromelains, byproducts, catfish, emulsifying, engineering, enzymatic hydrolysis, enzyme activity, ficain, fillets, fish culture, foaming, hydrolysates, hydrolysis, models, papain, proteolysis, rural economics, subtilisin, temperature, thermolysin, United States
Channel catfish farming is the most important warm water aquaculture in the United States and is very important to the rural economy. This study's objective was to investigate the kinetics of the enzymatic hydrolysis of catfish by-product. Channel catfish (Ictalurus punctatus) by-products (heads and frames) were collected from local catfish processing plant. Papain, ficin, bromelain, neutrase, alcalase, protamex, novo-proD and thermolysin were used for hydrolysis. Proteolytic activities of those proteases were examined at different hydrolysis temperature, proteases cost for reaching certain degree of hydrolysis was predicted. Degree of hydrolysis (DH) of the hydrolysates and hydrolysis kinetics were studied. Emulsifying and foaming property and stability of selected hydrolysates were evaluated. Results indicated that thermolysin had the highest activity (8.2 × 108 Azocoll U/g and 5.6 × 106 Azocasein U/g) at 70 °C. The highest DH of the hydrolysates were observed in 120 min with the concentration of 80 AzU/g for all enzymes. Ficin (80 AzU/g) was the most efficient in hydrolyzing the by-product (DH reaching 71%) in 120 min at 30 °C. The hydrolysis curves fit the Peleg model well with R2 higher than 0.91. This study provides important engineering information for choosing proteases and processing conditions for optimization of efficiency, yield and economy.