Ali Gholami, Mohammad Sadegh Taghizadeh, Ali Moghadam, Alireza Afsharifar, Ali Niazi
Plant protein hydrolysates are increasingly explored as sustainable functional ingredients; however, limited information is available on the structure–function relationships and stability of hydrolysates derived from Ferula assafoetida seed protein as a safe and bioactive source. Thereby, this study aimed to elucidate the structural, functional, and antioxidant properties of its protein hydrolysates. Seed proteins were extracted using an alkaline method, yielding 38.0 ± 0.2 mg/g, and subsequently hydrolyzed enzymatically. Hydrolysis markedly reduced particle size (from 1663.1 to 274.6 nm) and dispersity, accompanied by a shift in ζ-potential from −19.1 to −2.0 mV, indicating altered surface charge and improved colloidal uniformity. Structural analyses (SEM, FT-IR, XRD, UV-Vis, and SDS-PAGE) confirmed extensive protein degradation into peptides <10 kDa, decreased crystallinity, and the formation of new β-sheet and β-turn conformations, along with the presence of aromatic and phenolic components. Functionally, the hydrolysates exhibited enhanced solubility across a wide pH range, particularly under alkaline conditions, increased water-holding capacity (1.82 to 2.67), and improved foaming capacity (23.4 to 31.3%), although with reduced oil holding capacity, long-term foam, and emulsion stability compared to the native protein. The hydrolysates retained considerable antioxidant activity after heat and pH treatments, with maximum DPPH scavenging at neutral pH (84.89%), while simulated gastrointestinal digestion reduced activity (IC 50 : 15.93 → 42.39 μg/mL). Notably, the most active RP-HPLC fractions showed no cytotoxic effects. Overall, these findings demonstrate that F. assafoetida seed protein hydrolysates possess favorable structural flexibility, functional performance, and bioactivity, highlighting their potential as safe and effective functional ingredients for food applications.