Fabrication of zein and κ-carrageenan colloidal particles for encapsulation of quercetin: In-vitro digestibility and bio-potential activities

Abstract

The present work aims to prepare and stabilize quercetin (Q) loaded zein colloidal nanoparticles using κ-carrageenan (KC) as a stabilizer. Antisolvent precipitation method was used to fabricate the zein-KC colloidal nanoparticles at pH 5.0. The findings revealed that the newly prepared Q-loaded zein-KC complex colloidal particles had spherical shapes, a particle size below ∼300.0 nm, a high magnitude of negative zeta potential (∼−45.0 mV) and encapsulation efficiency of 62.0%. The molecular interactions among zein, Q and KC in colloidal particles were confirmed by FT-IR analysis, and the combined mixture showed an amorphous diffraction pattern during the XRD analysis without revealing the crystalline peaks of Q or KC, indicating that Q was effectively encapsulated in complex colloidal particles. In aqueous environments, the anionic KC coating on the surface of zein colloidal particles modified the particulate and physicochemical properties of the encapsulated Q and enhanced its water dispersibility, thermal stability, and in-vitro release. The observed improvements were ascribed to hydrogen bonding, hydrophobic and electrostatic interactions among Q, zein, and KC. In addition, Q-loaded zein-KC complex colloidal particles demonstrated strong antioxidant activity. The results of this study revealed that, the KC coated zein colloidal particles, therefore, have great potential for use in hydrophobic nutraceutical encapsulation.