Ultrasound-assisted preparation of antioxidant peptides in flaxseed meal: Purification, characterization and molecular docking analysis.

Flaxseed meal is recognized as a rich source of high-quality protein, and this study aims to explore its potential as a source of bioactive peptides. Hydrolysates were prepared via ultrasound-assisted enzymatic hydrolysis. Enzymatic hydrolysates from hot-pressed flaxseed meal showed higher biological activity than those from cold-pressed samples. Three antioxidant peptides, namely PFFWLHHT, HCLEFLSPRF, and ALTMPHNW, were identified and screened from the purified fractions of hot-pressed flaxseed meal using reversed-phase liquid chromatography-mass spectrometry (RPLC-MS) and in silico analysis. These peptides displayed scavenging activity against DPPH radicals (IC₅₀ = 0.520, 1.190, and 1.036 mM) and hydroxyl radicals (IC₅₀ = 4.909, 6.471, and 7.076 mM). Molecular docking studies indicated that three peptides could inhibit myeloperoxidase (MPO) activity by occupying the entrance of the active cavity, with their binding affinities measured at -12.2, -9.1 and – 11 kcal/mol, respectively. These findings could lay a foundation for extracting natural antioxidant peptides from flaxseed meals.