Pressure-assisted enzymatic hydrolysis (100 MPa) of chicken breast: enzyme-dependent effects on hydrolysis efficiency, peptide profile, microbial quality, and oxidative stability

Summary

High hydrostatic pressure (HHP) at 100 MPa, applied for up to 12 h depending on the experimental series, was used as an aid to enzymatic hydrolysis of fresh chicken breast (CBM) using three commercial proteases (Alcalase, Bromelain, and Flavourzyme), with atmospheric hydrolysis serving as the control. HHP preserved enzyme activity, with Alcalase retaining 72% of its initial activity after 6 h and increased the degree of hydrolysis (DH) of Alcalase by up to 11%, reaching a maximum DH of 51.7–51.8% across tested conditions. Hydrolysis efficiency further depended on enzyme-to-substrate (E/S) ratio and pH for Alcalase and Flavourzyme, but not for Bromelain, confirming enzyme-dependent sensitivity to these parameters. Mass spectrometry revealed a similarly enzyme-dependent pressure effect on peptide size: for Bromelain, pressure accelerated hydrolysis without altering the peptide size distribution, whereas for Alcalase and Flavourzyme, it moderately shifted peptides towards smaller sizes. HHP suppressed total aerobic bacterial growth over the 12 h hydrolysis period, while atmospheric processing permitted bacterial proliferation; yeast and mould counts declined under both conditions, but more markedly under HHP. Lipid oxidation was reduced under HHP for Bromelain and Flavourzyme, but not for Alcalase. HHP at 100 MPa enhanced hydrolysis efficiency, enzyme stability, and microbial quality of CBM hydrolysates, although several of these benefits were enzyme-specific rather than universal.