title: Adsorption and desorption properties of macroporous resins for anthocyanins from the calyx extract of roselle (Hibiscus sabdariffa L.).
abstract: Adsorption of roselle anthocynins, a natural pigment, onto various macroporous resins was optimized to develop a simple and efficient process for industrial separation and purification of roselle anthocyanins. Nine different macroporous resins (AB-8, X-5, HPD-100, SP-207, XAD-4, LS-305A, DM-21, LS-610B, and LS-305) were evaluated for the adsorption properties of the anthocyanins extracted from the calyx extract of  Hibiscus sabdariffa  L. The influences of phase contact time, solution pH, initial anthocyanin concentration, and ethanol concentration with different citric acid amounts were studied by the static adsorption/desorption method. The adsorption isotherm data were fitted well to the Langmuir isotherm, and according to this model, LS-610B and LS-305 exhibited the highest monolayer sorption capacities of 31.95 and 38.16 mg/g, respectively. The kinetic data were modeled using pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations. The experimental data were well described by the pseudo-second-order kinetic model. Continuous column adsorption-regeneration cycles indicated negligible capacity loss of LS-305 during operation. The overall yield of pigment product was 49.6 mg/g dried calyces. The content of roselle anthocynins in the pigment product was 4.85%.
authors.affiliation: School of Life Sciences, Yantai University, Yantai, People's Republic of China.
authors.forename: Xiu-Lian
authors.initials: XL
authors.lastname: Chang
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Bi-Yun
authors.initials: BY
authors.lastname: Chen
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Feng
authors.forename: Shao-Hong
authors.initials: SH
authors.lastname: Wen
authors.forename: Peng-Yuan
authors.initials: PY
authors.lastname: Zhan
mesh_terms: D000327:Adsorption; D000872:Anthocyanins / Q000737:chemistry / Q000302:isolation & purification*; D035264:Flowers / Q000737:chemistry*; D031584:Hibiscus / Q000737:chemistry*; D007202:Indicators and Reagents; D007700:Kinetics; D010936:Plant Extracts / Q000737:chemistry*; D013343:Styrenes / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D007202:Indicators and Reagents; D010936:Plant Extracts; D013343:Styrenes