Improvement of crocin stability by biodegradeble nanoparticles of chitosan-alginate.

This study aimed to improve the stability of crocin, a saffron carotenoid, encapsulating into chitosan (Cs)-sodium alginate (Alg) nanoparticles prepared by a modified ionic gelation method were investigated as a new carrier to improve the stability of crocin. Response surface methodology was used to optimize the important variables, namely the concentrations of Cs and Alg, and pH influencing the particle size, zeta-potential, and encapsulation efficiency to find the optimum formulation for production of crocin nanoparticles (CNPs). Microscopic analysis and dynamic light scattering examination indicated non-smooth and spherical nanoparticles with the size range of 165-230 nm in weight ratio of Cs:Alg (1:1.25) and pH 4.7. Fourier transform-infrared spectroscopy displayed an extensive hydrogen bonding interaction between the crocin and biopolymers. Encapsulation efficiency, loading capacity and yield of CNPs were 38.16, 30.96 and 48.33%, respectively. The zeta-potential of NPs was about -33.52 mV which resulted in the better stability of NPs during manipulation and storage. Stability studies showed that nanoencapsulation provided enhanced crocin stability with biopolymers compared to the standard crocin under unfavorable environmental conditions.