June 23/Stuttgart, Germany/Journal of Technology & Science -- According to a study from Stuttgart, Germany, "The purification and fractionation of phenolic compounds from crude plant extracts using a food-grade acrylic adsorbent were studied at pilot-plant scale. A diluted apple juice concentrate served as a model phenolic solution for column adsorption and desorption trials."

"Phenolic concentrations were evaluated photometrically using the Folin-Ciocalteu assay and by HPLC-DAD. Recovery rates were significantly affected by increasing phenolic concentrations of the feed solutions applied to the column. In contrast, the flow rate during column loading hardly influenced adsorption efficiency, whereas the temperature and pH value were shown to be crucial parameters determining both total phenolic recovery rates and the adsorption behavior of individual polyphenols. As expected, the eluent composition had the greatest impact on the desorption characteristics of both total and individual phenolic compounds. HPLC analyses revealed significantly different elution profiles of individual polyphenols depending on lipophilicity," wrote D.R. Kammerer and colleagues, University of Hohenheim.

The researchers concluded, "This technique allows fractionation of crude plant phenolic extracts, thus providing the opportunity to design the functional properties of the resulting phenolic fractions selectively, and the present study delivers valuable information with regard to the adjustment of individual process parameters."

Kammerer and colleagues published the results of their research in the Journal of Agricultural and Food Chemistry ("Pilot-Scale Resin Adsorption as a Means To Recover and Fractionate Apple Polyphenols." Journal of Agricultural and Food Chemistry, 2010;58(11):6787-6796).

For additional information, contact D.R. Kammerer, University of Hohenheim, Institute Food Science & Biotechnology, Chair Plant Foodstuff Technology, Garbenstr 25, D-70599 Stuttgart, Germany.

From the July 6, 2010, Prepared Foods E-dition