Malondialdehyde and peroxyl radical-driven oxidation of myofibrillar proteins to improve the gelation and emulsification properties

Abstract

During meat processing, the oxidation of fats and oils generates peroxyl radicals (ROO·) and malondialdehyde (MDA) which influence the gelation and emulsification properties of myofibrillar protein (MP). In this study, we investigated molecular structural changes and alterations in the functional properties of MPs induced by oxidation with MDA and ROO·. The results revealed that oxidation significantly increased the levels of di-tyrosine and carbonyl groups, and led to an initial reduction, followed by an increase, in average particle size (P < 0.05). Spectroscopic analysis indicated that mild oxidation induced structural stretching in MPs, exposing internal hydrophobic groups and enhancing surface hydrophobicity. Additionally, the α-helix content of MPs decreased from 43.62 % and 44.12–31.69 % and 33.87 %, respectively. Our findings revealed that an optimized oxidative environment can significantly enhance the rheological properties, cooking loss and WHC of MPs. Specifically, gel hardness exhibited a biphasic response to oxidation, initially decreasing at low levels of oxidation and subsequently increasing as oxidation intensified. Furthermore, moderate oxidation by MDA and ROO· was found to improve both the emulsifying activity (EAI) and emulsifying stability (ESI) indexes of MPs, suggesting potential applications in enhancing the texture and stability of processed meat products.