Adsorption characteristics of crocin in the extract of gardenia fruits (gardenia jasminoides ellis) on macroporous resins

Abstract

To study resin adsorptions and investigate the differences between processes in crude extracts and microfiltrates, the adsorption characteristics of crocin in the extract of Gardenia jasminoides Ellis on 10 macroporous styrene-divinylbenzene (SDVB) resins were investigated. Ground gardenia fruit was extracted with water and the crude extract was partially purified by microfiltration. The crude extract and microfiltrate were mixed with the 10 resins until the adsorption of crocin reached equilibrium on resins. The adsorption followed the pseudo-second-order kinetics closely, but the data also fitted the first-order and intraparticle diffusion models. Furthermore, the Freundlich isotherm was found suitable for describing the equilibrate adsorption data. XAD-1180, HP20, HPD-100A and AB-8 stood out as the best performing resins in terms of their adsorptive capacities and selectivities for crocin. The thermodynamics of the adsorption process was shown to be spontaneous and exothermal in nature, and controlled by physical rather than chemical mechanisms. Adsorption with SDVB resins in conjunction with microfiltration was found to be an efficient process for the purification of crocin in gardenia extract. © 2008 Wiley Periodicals, Inc.