Optimization of ultrasound-assisted enzymatic hydrolysis of channel catfish (Ictalurus punctatus) frames yield high-calcium and high-amino acid hydrolysates

ABSTRACTIn this study, a high-calcium and high-amino acid fish frame hydrolyzate (FFH) was prepared from channel catfish (Ictalurus punetaus) through ultrasound-assisted enzymatic hydrolysis (UAEH). A 4-factor and 3-level Box-Behnken design of response surface methodology was employed to optimize the hydrolysis conditions, where the independent variables were sonication power (W), sonication time (min), enzyme activity (U) and water-substrate ratio (v/w). The degree of hydrolysis (DH) and soluble calcium content (SCC) were used as response factors. The optimal hydrolysis conditions were found to be sonication power (X1) = 492.91 W, sonication time (X2) = 15.01 min, enzyme activity (X3) = 6677.88 U, and water-to-substrate ratio (X4) = 3.56 v/w. Under these conditions, UAEH effectively disintegrated fish frame collagen and converted bound calcium to soluble calcium. Nevertheless, this study investigated the pattern of collagen transformation into short peptides and free amino acids throughout the degradation process. These findings highlight the potential of the FFH from channel catfish to serve as a foundation for creating highly nutritious food additive. The outcomes of this study further enhance the food industry’s ability to capitalize on the nutritional benefits offered by fish frame hydrolyzates. This expansion of health-focused product options and endorsement of the sustainable use of fish by-products harmonizes seamlessly with the industry’s evolving goals of waste reduction and value optimization.