Adsorption and desorption characteristics of macroporous resins to purple sweet potato pigments

The characteristics of static adsorption dynamics, adsorption isotherm and desorption of four kinds of macroporous resins (AB-8, S-8, NKA-II and NKA-9) to purple sweet potato pigments (PSPPs) were investigated. The results indicate that the AB-8 type macroporous resin is the suitable resin for the adsorption of PSPPs with the maximal velocity constant of absorption equilibrium, and its adsorption amount is 1.19, 1.39 and 1.18 times of that of S-8, NKA-II and NKA-9 type macroporous resines respectively. Meantime, its desorption amount is 1.05, 1.16 and 1.18 times of that of S-8, NKA-II and NKA-9 type macroporous resines. The results of desorption trail suggest that 60% ethanol solution is the optimum solution for the desorption of purple sweet potato pigments.