A Comparison of Polyvinylpolypyrrolidone (PVPP), Silica Xerogel and a Polyvinylpyrrolidone (PVP)-Silica Co-Product for Their Ability to Remove Polyphenols from Beer
Alyson E. Mitchell1, Yun-Jeong Hong1, J. Cale May1, Christine A. Wright1 and Charles W. Bamforth1,2
1 Department of Food Science and Technology, University of California, Davis, CA 95616-8598.
2 Corresponding author. E-mail: cwbamforth@ucdavis.edu
J. Inst. Brew. 111(1), 20-25, 2005 | VIEW ARTICLE
ABSTRACT
Proanthocyanidins have been characterized and levels compared in an ale and a lager using normal-phase liquid chromatography- mass spectroscopy (LC/MS) after a pre-concentration step employing Sephadex LH-20 chromatography. Twenty proanthocyanidins were identified including both non-galloylated and galloylated forms of the monomers, dimers and trimers. Oligomers greater than trimer were not detected. A proportion of all classes of proanthocyanidin adsorbed non-specifically to a silica xerogel product, but polyvinylpolypyrrolidone (PVPP) and a product that comprises polyvinylpyrrolidone (PVP) on a surface of amorphous silica displayed greater capability (i.e. specificity) for binding these materials. Of the two specific adsorbents, it was the PVPP that had the greater binding capability compared to the PVP-silica co-product.
Key words:
Beer, high-performance liquid chromatography, mass spectrometry, polyphenolics, polyvinylpolypyrrolidone, proanthocyanidins, PVP-silica composite, silica.
Publication no. G-2005-0318-270 ©2005 The Institute & Guild of Brewing