Peptidomics reveals enhanced bioactivities of hempseed cake induced by solid-state fermentation

Novel peptides generated from solid-state fermented hempseed cake were characterized by peptidomics and validated for bioactivity. Fermentation with Aspergillus niger, Bacillus subtilis, and Lactobacillus rhamnosus markedly increased peptide numbers compared with the unfermented control and promoted the release of short peptides mainly from Cupin type-1 domain proteins, with leucine frequently occurring at cleavage termini. In silico prediction and molecular docking identified antioxidant, angiotensin-converting enzyme (ACE), and dipeptidyl peptidase-IV (DPP-IV) inhibitory candidates. Synthesized peptides confirmed that LDVSP and LVSPL showed potent ACE inhibition, with IC50 values of 107.47 ± 6.57 and 127.06 ± 12.11 μM, respectively, while LVSPL also inhibited DPP-IV (IC50 = 2.21 ± 0.04 mM). B. subtilis fermentation yielded the strongest antioxidant and ACE-inhibitory activities, whereas A. niger produced the highest DPP-IV inhibitory activity, highlighting fermented hempseed cake as a promising source of multifunctional bioactive peptides.