abstract
- The effect of adding sodium bicarbonate(SB) and citric acid(CA) in the subcritical water (SW) hydrolysis process was studied to improve peptide extraction from Sphenarium purpurascens. A complete factorial(23) design was accomplished, and the effects of the temperature, pressure and modifier concentration on the degree of hydrolysis(DH), molecular distribution, antioxidant activity and Angiotensin I-converting enzyme(ACE) inhibitory activity were evaluated. A protein concentrate was obtained and hydrolyzed, showing a DH of up to 44.56 ± 0.92% with the addition of 1 M SB at 130 °C/20 MPa; meanwhile, 38.73 ± 0.58% was observed using CA under the same conditions. The best bioactivities were found in CA treatments: IC50 of up to 4.06 ± 0.35 mg/mL for DPPH, 330 ± 0.03 µg/mL for ABTS and up to 0.148 ± 0.016 mg/mL for the ACE inhibition activity. Moreover, differential hydrolysis was found due to the presence of modifiers and process conditions, being able to modulate the hydrolysis degree and obtaining hydrolysates with different characteristics and bioactivities.