Use of poultry by-products: production of functional ingredients with high bioactive value through the use of ultrasound-assisted enzymatic hydrolysis

The purpose of this research is to produce functional ingredients with high bioactive value. The objective of this study was to investigate the extraction of functional ingredients from chicken liver and heart by ultrasound-assisted enzymatic hydrolysis. A Box-Behnken design was employed to optimize process conditions, considering ultrasound treatment time, enzyme/substrate ratio, and enzymatic hydrolysis time as independent variables. The distribution of the peptide profile, amino acid composition, degree of hydrolysis, and antioxidant capacity of the hydrolysates were evaluated. Optimal conditions were determined to be 30 min of ultrasound treatment, a 0.1% enzyme/substrate ratio, and 75 min of enzymatic hydrolysis. Under these conditions, the hydrolysis rate reached 99.64%, and the resulting hydrolysates exhibited excellent antioxidant properties as measured by ABTS (503.9 µM ET), FRAP (84.53 mM ET), and Fe^+ 2 chelation (91.78%). Compared to traditional enzymatic hydrolysis, the ultrasound-assisted method yielded hydrolysates with a higher degree of hydrolysis, a greater generation of low molecular weight peptides (58.6%:17-1.35 kDa and 30.5%<1.35 kDa), and a higher content of biologically relevant amino acids (alanine, cysteine, glycine, lysine, aspartic acid, and glutamic acid). These results demonstrate the potential of ultrasound-assisted enzymatic hydrolysis for producing functional food ingredients with valuable bioactive properties from poultry by-products.