Study on the adsorption kinetics of organic acids and total flavonoids in hawthorn fruit juice

To investigate the adsorption kinetics of organic acids and total flavonoids in hawthorn fruit juice at the same time, hawthorn fruit juice containing different concentrations of organic acids and total flavonoids was designed, then mixed with a certain dose of the resin (D941 resin or NKA resin) and the adsorption occurred by stirring.The equilibrium data was analyzed in terms of the Langmuir and Freundlich isotherm models.As the results showed, the adsorption equilibrium data of organic acids and total flavonoids on D941 resin and NKA resin was fitted to the Langmuir isotherm model.The maximum adsorption capacities of organic acids and total flavonoids on the two resins were calculated respectively in term of the Langmuir isotherm model.It was found that the macroporous weakly basic anion exchange resin (D941) adsorbed more organic acids and less total flavonoids than the macroporous resin (NKA) .Therefore, D941 resin could be used as a more ideal resin reducing the content of organic acids but retaining the content of total flavonoids.The adsorption capacity of organic acids on D941 resin or NKA resin was lower than citric acid solution, which proved the adsorption of total flavonoids hindered the adsorption of organic acids.