Nanoencapsulation of zeaxanthin extracted from Lycium barbarum L. by complex coacervation with gelatin and CMC

This study developed nanocapsules by complex coacervation between gelatin (G) and sodium carboxymethyl cellulose (CMC) for the encapsulation of zeaxanthin extracted from Lycium barbarum L. The optimum pH and G-CMC mass mixing ratio were determined by analysis of the zeta potential, turbidity, morphology, particle size distribution, complex coacervate yield, emulsification stability index (ESI) and emulsification activity index (EAI). The formation mechanism of the G-CMC coacervates was examined by fourier transform infrared spectroscopy (FTIR) analysis. Moreover, the morphology, particle size distribution, thermal properties and in vitro simulated gastrointestinal digestion of zeaxanthin nanocapsules were investigated. The results showed that the optimum mass mixing ratio of G-CMC was 9:1 (w/w) with an optimum pH of 4.50. FTIR analysis confirmed the electrostatic interaction between the –NH3+ of G and the -COO- of CMC in the formation of G-CMC complex coacervates. Thermal gravimetric analysis (TGA) showed that nanoencapsulation could enhance the thermal stability of zeaxanthin. In vitro simulated gastrointestinal digestion experiments showed that zeaxanthin had good sustained release performance in simulated gastric fluid (SGF) and large amounts of zeaxanthin were released in simulated intestinal fluid (SIF).