Recovery of narirutin by adsorption on a non-ionic polar resin from a water-extract of Citrus unshiu peels

Narirutin can be successfully recovered from water-extracts of Citrus unshiu peels using the moderately polar acrylic resin, Amberlite XAD-7. The narirutin adsorption yield in this study was determined to be in excess of 95% at the following conditions for XAD-7 resin: three hours of equilibrium time, an initial narirutin concentration of at least 1500 mg/l, and a resin content equal to 40 times the narirutin concentration. The adsorption isotherm of narirutin on XAD-7 resin is appropriately described by the Freundlich equation. The constants, K and n, from Freundlich's adsorption isotherm were determined to be 7.89 and 0.34, respectively. The optimum desorption yield was found to be in excess of 89%, when 80% methanol was used as a desorption solvent. In conclusion, the recovery of narirutin from water-extracts of Citrus unshiu peels can be easily and effectively achieved via adsorption and desorption on Amberlite XAD-7, which has been shown to generate a final recovery yield of approximately 84%. The results of this study bring us closer to a batch process method for the large-scale production of narirutin.