High-pressure homogenization pretreatment enhances flavonoid release and bioactive peptide production in quinoa protein hydrolysates: In vitro and in silico analysis of bioactive properties

This research explored the impact of high-pressure homogenization (HPH) at 50, 100, and 180 MPa as a pretreatment for enzymatic hydrolysis of quinoa protein isolate (QPI) using Alcalase, focusing on protein solubility, protein profile, degree of hydrolysis (DH), free amino acids, total soluble phenolic compounds (TSPC), angiotensin-converting enzyme-inhibitory (ACEI) and antioxidant activities (AA), and characterization of phenolics and peptides. Pretreatment at 50 MPa (QPH50) reduced DH from 15.98 % (non-pretreated hydrolysates) to 13.53 %. The hydrolysates comprised low free amino acid levels (2.5–2.7 g/100 g). Soluble protein decreased, and SDS-PAGE confirmed globulin hydrolysis (>25 kDa) for all hydrolysate samples, with an increase in small peptides (<5 kDa). QPI hydrolysis increased TSPC and AA in methanol-acetone and aqueous extracts, reaching their highest levels at 50 MPa (aqueous extract). The 3 kDa permeates showed strong ACEI activity at 0.5 mg/mL (91.5–93.2 %), with QPH50 exhibiting the highest inhibition (92.6 %; IC50 = 0.04 mg/mL). Further characterization of QPH50 showed enhanced flavonoid content (10.1 mg/100 g). Peptidomic analysis of QPH50 identified 236 peptide sequences, 27 predicted bioactive, with SPGYYDGR and AGLQFPVGR ranking highest for multifunctional potential. This study highlights the effectiveness of combining HPH with enzymatic hydrolysis to release phenolics and bioactive peptides, with high bioavailability and promising safety profiles.