Kvasny Prum. 2003; 49(7-8): 188-191 | DOI: 10.18832/kp2003014

Turbidimetric Titration Analyses of Classical Kieselguhr Filtration.Peer-reviewed article

Petr SLADKÝ, Miroslav DIENSTBIER

Katedra chemické fyziky a optiky, MFF UK, Ke Karlovu 3, 121 16 Praha 2

Turbidity of pale beer was measured in two angles of scattered light during the conventional kieselguhr filtration and further analysed using developed rapid turbidimetric titration methods. Although the turbidity of the filtrate decreased during the filtration process, the colloidal instability of the filtrate markedly increased as it was revealed by alcohol chill haze test and confirmed by thermal forcing method. Turbidimetric PVP titration of the filtrated beer indicated growth of the Chapon`s tannoids with the filtration time. Also an increase of anthocyanogenes and total polyphenols, measured for the control as a function of time of the filtration, was observed. The effect was qualitatively explained by elution of wide spectrum of polyphenolic complexes from kieselgur/retained particles layer adjacent to the filter candle back to filtrate. The elution of polyphenols from the growing filtration cake with time is probably very complex chromatographic process of both ion-exchange and size-exclusion type. The findings are important for the effective control of beer stabilization process, particularly in the case of the regenerable PVPP technology.Turbidity of pale beer was measured in two angles of scattered light during the conventional kieselguhr filtration and further analysed using developed rapid turbidimetric titration methods. Although the turbidity of the filtrate decreased during the filtration process, the colloidal instability of the filtrate markedly increased as it was revealed by alcohol chill haze test and confirmed by thermal forcing method. Turbidimetric PVP titration of the filtrated beer indicated growth of the Chapon`s tannoids with the filtration time. Also an increase of anthocyanogenes and total polyphenols, measured for the control as a function of time of the filtration, was observed. The effect was qualitatively explained by elution of wide spectrum of polyphenolic complexes from kieselgur/retained particles layer adjacent to the filter candle back to filtrate. The elution of polyphenols from the growing filtration cake with time is probably very complex chromatographic process of both ion-exchange and size-exclusion type. The findings are important for the effective control of beer stabilization process, particularly in the case of the regenerable PVPP technology.

Keywords: turbidimetry, kieselguhr filtration, haze

Published: July 1, 2003