Abstract:Proanthocyanidin is a natural polyphenol compound with strong antioxidant activity.In this paper，casein and maltodextrin were used for molecular self-assembly.Amphiphilic biopolymers obtained were used to combine with proanthocyanidins to form nanocomposites.The interaction mechanism between casein and maltodextrin was analyzed by grafting degree，browning degree，protein solubility，infrared spectrum and circular dichroism.The encapsulation efficiency was taken as indexes to optimize the technological conditions for the construction of proanthocyanidin nanocomposites.The particle size，Zeta potential and polydispersity index of proanthocyanidin nanocomposites were characterized，and the morphological changes of the nanocomposites before and after embedding were observed by scanning electron microscopy（SEM）.The results showed that casein and maltodextrin were successfully self-assembled，which effectively improved the solubility of casein.When the mass ratio of proanthocyanidins to grafts was 2 ∶5，the concentration of the grafts was 25 mg/mL and the solution pH was 7.0，the encapsulation efficiency of the prepared proanthocyanidins nanocomposites reached 93.48%，the average particle size was 158.69 nm，and the Zeta potential was-30.58 mV.Proanthocyanidin nanocomposites exhibit a compact spherical structure withsmooth surface.