A comparison of polyvinylpolypyrrolidone (PVPP), silica xerogel and a polyvinyl pyrrol idone (PVP)-silica co-product for their ability to remove polyphenols from beer

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 proanthol cyanidins were identified including both non-galloylated and galloylated forms of the monomers, dimers and trimers. Oligo mers greater than trimer were not detected. A proportion of all classes of proanthocyanidin adsorbed non-specifically to a silica xerogel product, but polyvinylpolypyrroliclone (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.