Co-encapsulation of quercetin and resveratrol: Comparison in different layers of zein-carboxymethyl cellulose nanoparticles.

Three nanoparticles were fabricated for the co-delivery of quercetin and resveratrol. Nanoparticles consisted of a zein and carboxymethyl cellulose assembled using antisolvent precipitation/layer-by-layer deposition method. Nanoparticles contained quercetin in the core and resveratrol in the shell, resveratrol in the core and quercetin in the shell or both quercetin and resveratrol in the core. The particle sizes of nanoparticles were 280.4, 214.8, and 181.8 nm, respectively. Zeta-potential was about -50 mV and PDI was about 0.3. The different positions of polyphenol distribution nanoparticles could reduce the competition between the two polyphenols, the encapsulation rate, loading rate and storage stability reached up to 91.7 %, 5.37 % and 97.1 %, respectively. FT-IR showed that hydrophobic and electrostatic interactions were the main driving forces of nanoparticle assembly. XRD showed that two polyphenols were successfully encapsulated in nanoparticles. TGA showed that distributing the nanoparticles in different layers would enhance thermal stability. TEM and SEM showed that polysaccharides attached to the surface of nanoparticles formed a core-shell structure with uniform particle size. All three nanoparticles could release two polyphenols slowly in simulated gastrointestinal digestion, Korsmeyer-Peppas was the most suitable kinetic release model. Therefore, biopolymer-based nanocarriers can be created to enhance the loading, stability, and bioaccessibility of co-encapsulated nutraceuticals.