Comparative study of the effects of different lipid oxidation simulation systems on the physicochemical properties of proteins isolated from four cultivated walnut (Juglans sigillata Dode) varieties

This study aimed to investigate the effects of different lipid oxides on the physicochemical properties of proteins isolated from four walnut cultivars (YBWPI, NQWPI, XXWPI and STWPI). The main proteins in these WPIs are legume B-like and 11S globulin-like, and XXWPI contained the most unique proteins. In three simulation systems, YBWPI showed the greatest changes in carbonyl value, free sulfhydryl value and intrinsic fluorescence intensity. The secondary structure of STWPI changed obviously. NQWPI showed a unique subunit depolymerization, and its solubility and exogenous fluorescence intensity changed significantly, whereas emulsification and particle size of XXWPI changed the most. The 11S globulin-like and cupin type-1 domain-containing protein (A0A833YDI2) have stronger affinities with the key lipid oxides. The radius of gyration and total solvent accessible surface area values of the legumin B-like protein after oxidation reduced obviously. This study may help to better understand the interrelationship between lipid oxides and walnut protein properties.