Recovery and fractionation of major apple and grape polyphenols from model solutions and crude plant extracts using ion exchange and adsorbent resins

Model systems composed of phenolic compounds, amino acids and mixtures thereof mimicking apple pomace and grape skin extracts were used to examine adsorption and ion exchange behaviour of one adsorbent as well as four anion and four cation exchange resins in a column system at pH 1, 5 and 7. Furthermore, apple pomace and grape skin extracts were loaded onto the resins to evaluate the transferability of the results obtained in the model experiments. In addition, different eluents were applied for the successive recovery of phenolic compounds from the resins. The results provide valuable information on highly complex adsorption and exchange systems. The data indicate both enhanced and decreased polyphenol binding rates as a result of amino acid addition depending on the composition of the solutions applied to the resins. The application of appropriate process parameters during adsorption and desorption was shown to allow selective recovery of compound classes or even individual compounds. As the model experiments did not allow complete prediction of polyphenol binding behaviour, further extract compounds not investigated in the present study presumably also interfere with polyphenol recovery. The results help to systematically optimise industrial processes, thus improving cost‐efficiency and selectivity of polyphenol recovery.