Succinylated Starch Nanocapsules Loaded with the Polyphenolic Extract from Arugula (Eruca sativa) Leaves: Colloidal, Chemical, and Structural Properties

The aim of this study is to incorporate the polyphenolic-rich extract from Eruca sativa leaves into succinylated starch nanocapsules. Synthesis of the nanocapsules is carried out using an industrial/scale ultrasonic equipment, and the dynamic light scattering (DLS), infrared spectroscopy (FTIR), X-ray diffraction (XRD), and microscopy (FE-SEM) techniques are used for determining the colloidal, chemical, and structural properties, respectively. Non succinylated nanocapsules and succinylated nanocapsules with two degrees of substitution (DS; 0.01 and 0.03) are synthetized. The unloaded nanocapsules exhibits a hydrodynamic size ranging from 50 to 69 nm, but the nanoencapsulation has a significant effect (p < 0.05) on the colloidal properties of loaded nanocapsules. All of the three loaded nanocapsules demonstrates hydrodynamic sizes ranging from 259 to 268 nm, a polydispersity index (PDI) of 0.361 to 0.390, zeta-potential values of -11.43 to -15.98 Mv, and encapsulation efficiencies (EE) of 16%. FTIR results show hydrophobic interactions between E. sativa polyphenols and nanoparticles. Additionally, the XRD results suggest the formation of slight inclusion complexes between E. sativa polyphenols and nanoparticles. The starch nanoparticles are efficient to encapsulate a polyphenolic-rich ethanolic extract and the succinylation influences the nanoparticle-extract molecular interactions and arrangements but not EE.