Interaction between cross-linked cationic starch microgranules and chlorogenic acid isomers in artichoke and green coffee bean aqueous extracts.

In the present study, the adsorption of phenolic compounds, first of all, chlorogenic acid isomers (chlorogenic, neo-chlorogenic and crypto-chlorogenic acids) predominant in the artichoke (AE) or green coffee bean (GCBE) extracts on cross-linked cationic starch having quaternary ammonium groups (CCS) has been investigated. The equilibrium adsorption studies showed that adsorption closely followed the Langmuir adsorption model, i.e. anionic substances of the extracts were interacting with quaternary ammonium groups of CCS. The UPLC-UV-MS/MS analysis showed that 8% and 17% of chlorogenic acid isomers of the total amount of adsorbed phenolics form AE and GCBE, respectively, were immobilized on CCS. The desorption study of phenolics from AE/CCS and GCBE/CCS complexes revealed that amount of desorbed AE or GCBE phenolics depended on the desorption medium. The antioxidant activity investigation showed that the immobilization of active components of extracts on CCS prevented the rapid loss of antioxidant activity. The results suppose that adsorption on modified starch technique can be successfully employed to remove important amounts of bioactive compounds from plant extracts by employing effective, sustainable and environmental friendly procedures.