LAUSR

BACKGROUND The extracted proteins from alternative animal origins tend to present strong off-flavor perception due to physico-chemical interactions of coextracted off-flavor compounds with proteins. To investigate the relationship between absorption behaviors of volatile aromas and the processes-induced variations in protein microstructures and molecular conformations, duck liver protein isolate (DLp) was subjected to heating (65/100 o C, 15 min) and ultra-high pressure (UHP, 100-500 MPa/10 min, 28 o C) treatments for obtaining differential unfolded protein states. RESULTS Heat- and UHP-treatments induced the unfolding of DLp with varied degrees, revealed by the fluorescence spectroscopy, ultraviolet-visible absorption, circular dichroism spectra, and surface hydrophobicity measurements. Two types of heating-denatured states with varied unfolding degrees were obtained, while UHP at both levels of 100/500 MPa caused partial unfolding of DLp and the presence of molten-globule state, which significantly enhanced the binding affinity between DLp and (E, E)-2,4-heptandienal. Particularly, significantly modified secondary structures of DLp were observed in heating-denatured samples. Excessive denaturing and unfolding degrees resulted in no significant changes in the absorption behaviors of the volatile ligand as characterized by the observations of fluorescence quenching and the analysis of headspace concentrations. CONCLUSION Defining processes-induced conformational transition behaviors of matrix proteins could be a promising strategy to regulate food flavor attribute and particularly, to produce DLp coextracted with limited off-flavor components by modifying their interaction during extraction processes. This article is protected by copyright. All rights reserved.