Combining ultra-high pressure with propylene glycol and trehalose to inhibit co-elution of off-flavor components during liver protein extraction.

Off-flavor compounds often bind to proteins during extraction from animal byproducts and compromise protein applicability. This study proposed the integration of ultra-high pressure (UHP) pretreatment with propylene glycol and trehalose addition (UNPA) to facilitate off-flavor dissociation during duck liver protein (DLvP) extraction. UHP treatment at 350 MPa for 10 min induced a molten globule-like state with loosened tertiary packing and increased hydrophobic exposure, whereas propylene glycol and trehalose helped maintain the pressure-modulated conformation and limit aggregation. UNPA decreased the total peak area of headspace volatiles by approximately 50.8%, and reduced trimethylamine, dimethylamine, histamine, and formaldehyde by 28.78%, 32.19%, 12.21%, and 44.00%, respectively (p < 0.05). Water-holding capacity and emulsifying activity were improved by 13.6% and 60.1%, respectively (p < 0.05). These findings indicate that controlled UHP-induced unfolding, assisted by conformational stabilization, can promote off-flavor release while improving selected functional properties of DLvP.