RHEOLOGICAL PROPERTIES OF LIQUID SURFACE LAYER IN SELECTED COMMERCIAL BEERS

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RHEOLOGICAL PROPERTIES OF LIQUID SURFACE LAYER IN SELECTED COMMERCIAL BEERS

Journal Title: Żywność. Nauka. Technologia. Jakość - Year 2014, Vol 21, Issue 4

Abstract

In the paper, the results are presented of a rheological examination of surface layers of the Dębowe Mocne, Tyskie Gronie, Żywiec, and Warka Strong beers in an oscillatory flow. The obtained interfacial correlations between the interfacial storage modulus Gs’ and interfacial loss modulus Gs”, expressed as a function of time, had a form characteristic for diluted aqueous protein solutions. For all the beers examined, the values of the two moduli increased and, after some time, that was characteristic for the given type of beer, intersected at one point on the graph. The results of oscillatory measurements prove that a network structure was formed in the surface layers of the beers examined. A very long time necessary for that structure to form proves that the proteins in beer played an important role in forming the structure. Furthermore, it was found that the most stable froth foam occurred on the surface of the Żywiec beer. The values of the measured values of the Gs’ and Gs” interfacial moduli were the highest. Those results show that there is a correlation between the rheological properties of the liquid surface layer and the stability of the beer froth foam.

Authors and Affiliations

Lubomira Broniarz-Press, Jacek Różański, Sylwia Różańska, Joanna Kmiecik

Keywords

EP ID EP152862
DOI 10.15193/zntj/2014/95/043-052
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