Stability and structural characteristics of amylopectin nanoparticle-binding anthocyanins in Aronia melanocarpa

The bioavailability of anthocyanins from Aronia melanocarpa is limited by their high degradation rates and poor stability. One way to protect anthocyanins is to deliver them using amylopectin nanoparticles (APNPs). In this study, we used distilled water as the reaction system, and achieved the most stable formulation of anthocyanins and APNPs using a mass ratio of 1:12, a pH of 3, and a binding time of 60 min, at which the binding rates were 81.52%, 82.67%, and 84.00%, respectively. Moreover, electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy were applied to observe microstructural changes with each combination. The observed stabilities and antioxidant activities indicated that binding played a role in protecting anthocyanins from heat, oxidization, reduction reactions, and metallic ions. Finally, our in vitro-digestion results suggested that the optimized compound can partially avoid degradation and diffusion, wherein the anthocyanin retention rate and FRAP value increased to 17.05% and 24.85%, respectively.