Preparative separation of Rebaudiana A from commercialized steviol glycosides by macroporous adsorption resins mixed bed

This work focused on the separation and purification of commercialized steviol glycosides (SGs) by macroporous adsorption resins (MARS) mixed bed through the adsorption and desorption experiments. Firstly, the influence of functional groups on the separation degree of Rebaudiana A (RA) were investigated based on gel type ion exchange resins (GIRs), and the result showed the group of -N(CH3)(2) was the best. Then, 21 sorts of MARs were screened one by one with adopting the separation degree of RA as the prior index, then the mixed bed of MARs that contained two, three,...till six were investigated in turn to find the most effective separation MARs mixed bed, and the results showed that MARs mixed bed LZ-1+LZ-20+LZ-30+LZ-37+LZ-36 had the higher separation efficiency than the others. Besides, the experimental data of MARs mixed bed LZ-1+12-20+LZ-30+LZ-37+LZ-36 well fitted the pseudo-second-order kinetics model and Brunauer's IV adsorption isotherm model. And it was found that the intra-particle diffusion process was rate-limiting step. After that, the separation parameters of RA from commercialized SGs were optimized through adsorption and desorption experiments. And under the obtained optimum separation conditions, the separation degree increased from 0.838 to 0.9196 with a recovery yield of 91.67% through only one cycle adsorption and desorption. (C) 2012 Published by Elsevier B.V.