Effect of Malondialdehyde-induced Oxidation Modification on Physicochemical Changes and Gel Characteristics of Duck Myofibrillar Proteins

This paper focuses on the effect of malondialdehyde-induced oxidative modification (MiOM) on the gel properties of duck myofibrillar proteins (DMPs). DMPs were first prepared and treated with oxidative modification at different concentrations of malondialdehyde (0, 0.5, 2.5, 5.0 and 10.0 mmol/L). The physicochemical changes (carbonyl and free thiol group content) and gel properties (gel whiteness, gel strength, water holding capacity, rheological properties and mi-cro-structural properties) were then investigated. The results showed that the content of protein carbonyl groups increased with increasing MDA oxidation (P<0.05), while the content of free thiol groups decreased significantly (P<0.05). Meanwhile, there was a significant trend of decrease in gel whiteness; the hardness and water-holding capacity of protein gels increased significantly under the oxidation of low concentration of MDA (0-5 mmol/L), while the hardness of gels decreased under the oxidation of high concentration (10 mM). The storage modulus and loss modulus of oxidized DMPs also increased with increasing concentration; moreover, microstructural analysis confirmed that the gels oxidized at low concentrations were more compact and homogeneous in terms of pore size compared to the high concentration or blank group. In conclusion, moderate oxidation of malondialdehyde was beneficial to improve the gel properties of duck; however, excessive oxidation was detrimental to the formation of dense structured gels.