Interaction between casein and rice glutelin: Binding mechanisms and molecular assembly behaviours

The present study investigated the interaction between acid casein and rice glutelin (RG) under neutral conditions. Large particle populations contain casein-RG complex which consisted of β-casein, αs1-casein, and RG was formed. The results of multispectral studies indicated that the peptide chain and secondary structure of casein did not change during the binding process. Besides, the binding behaviours seemed to be closely related to the surface hydrophobic region of RG. Thermodynamic parameter calculations showed that the main driving forces behind this structure formation were the hydrogen bonds and van der Waals forces. On the other hand, the addition of RG caused the generation of small particle populations (~20 nm) which mainly composed of κ-casein and αs2-casein, and such small particle populations maintained aggregation through residual calcium. Moreover, it is noting that these two particle populations can coexist stably, this finding will provide an avenue to produce, by design, casein nanoparticles.