Effect of Protein Oxidation on Interfacial Properties of Walnut Protein

The objective of this research was to study the effect of oxidization of malondialdehyde which was selected as a representative of reactive aldehydes produced in the process of polyunsaturated fatty acids lipid peroxidation catalyzed by lipoxygenase on the surface properties of walnut protein. Increasing extent of oxidation resulted in gradual carbonyl group generation and carbonyl content of walnut protein were increased from 3.12 nmol/mg to 20.61 nmol/mg. With the degree of oxidization was increased, the particle size of walnut protein was deviated, the relative molecular weight of protein first decreases and then increases and surface tension of walnut protein showed a trend of decrease first and then increase, as well as, the results of absolute value of Zeta potential, surface hydrophobicity, foaming capacity and foaming stability showed the trend of increase first and then decrease. When the concentration of malondialdehyde was to 0.1 mmol/L, the value surface tension of walnut protein reached the minimum, which was 55.64 mN/m, respectively; and the absolute value of Zeta potential, surface hydrophobicity, foaming capacity and foaming stability reached the maximum value, which were 10.38 mV, 476, 21.43% and 17.80%, respectively. Experimental results showed that the molecular structure and interface properties of walnut protein were changed with the oxidation of protein by malondialdehyde, and the interface properties of walnut protein could been improve at low degree of oxidation. © 2020, Editorial Office of Journal of CIFST. All right reserved.