Preparation, characterization, and stability of multi-layer nanoemulsions containing resveratrol

Abstract

The aim of this study was to enhance solubility and stability of resveratrol (RES) by dried multi-layer nanoemulsion (DNE) using the layer-by-layer (LBL) method. To prepare RES-loaded multi-layer nanoemulsions (NE), a coarse emulsion (PRI) using lecithin was coated with chitosan for the secondary emulsion (SEC) and polyglutamic acid (PGA) for the tertiary emulsion (TER). The RES-loaded NEs ranged in particle size from 107 to 133 nm, with homogeneous dispersion and high entrapment efficiency (99.6-99.8%). The particle sizes (150-172 nm) of RES-loaded DNE remained stable after lyophilization. The water solubility of DNE using PGA (TER-DNE) was improved by 1.8-2.0 times compared to that of FREE RES. Antioxidant activity increased from FREE RES (5-10%) to NE (6-19%) to DNE (12-24%). No significant difference in UV stability was determined for PRI (39-52%), SEC (40-51%) or TER (38-49%). The hydrogen peroxide stability increased from FREE RES (7-17%) to NE (33-40%) to DNE (37-47%). UV and hydrogen peroxide stability were increased by factors of 2.4-5.6 and 2.8-5.1, respectively, in PGA-DNE relative to FREE RES. Therefore, NE and in particular DNE are potentially valuable techniques for improving the solubility, antioxidant activity, and stability of RES.