Encapsulation of melatonin in zein/pectin composite nanoparticles: Fabrication, characterization, and in vitro...

In this study, the encapsulation of melatonin (MT) in zein nanoparticles was investigated via anti-solvent co-precipitation method with pectin stabilization. Compared with MT-loaded zein nanoparticles (MT-Z NPs), 1.0 mg/mL pectin led to a 92.1 % of MT encapsulation efficiency, a 5.4 % of MT loading, a particle size growth from 111.3 to 294.8 nm, a ζ-potential reduction from +4.8 to -41.4 mV, and an irregular surface shape. Moreover, the hypsochromic and redshifts of the OH and amide I bands, and undetected MT crystalline characteristic peaks in MT-loaded zein/pectin nanoparticles (MT-Z/P NPs) revealed successful MT embedment governed by hydrogen and hydrophobic forces. The binding energies of zein with MT and pectin (-6.89 and - 7.01 kcal/mol) confirmed the stability of complex. MT-Z/P NPs prolonged MT release from 92.3 % to 63.6 % at 6 h in gastrointestinal tract (GIT) compared with MT-Z NPs, which could be a desirable MT delivery material in food industry.