Molecular mechanisms of lipoxygenase-mediated linoleic acid oxidation products in the structural modification and...

This study used lipoxygenase-catalyzed lipid peroxidation to examine structural and functional alterations in chickpea protein isolate during oxidation. Oxidation level, assessed by measuring the amounts of carbonyl and free sulfhydryl groups, altered protein structure, as evidenced by endogenous fluorescence, FTIR, SDS-PAGE, and surface hydrophobicity analyses. Increasing oxidation led to a non-monotonic change in thermal behavior: the denaturation temperature initially decreased and then increased, accompanied by a corresponding increase and subsequent decrease in enthalpy. Moreover, a moderate linoleic acid content promoted structural unfolding and increased the proportion of charged amino acids, thereby improving in vitro digestibility by 3.28%. The emulsification properties also improved, with increases of 6.65% and 34.75% in the emulsification activity index and emulsion stability index, respectively, and a decrease of 18.31% in creaming index. This research demonstrates that far from being purely detrimental, legume protein oxidation under moderate oxidative conditions can effectively address key application limitations of plant proteins, such as suboptimal functionality and low bioavailability, thereby meeting the requirements of diverse food applications.