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Model Solution as a Beer Foam Standard Should Contain Fatty Acids

​Petr Kosin (1) and Jan Savel, Budejovicky Budvar, N.C., Karoliny Svetle 4, 370 21 Ceské Budejovice, Czech Republic; and Tomas Branyik and Filip Ulmann, University of Chemistry and Technology Prague, Department of Biotechnology, Technická 5, 166 28 Prague, Czech Republic. J. Am. Soc. Brew. Chem. 75(3):217-220, 2017.

​A reliable foam standard is needed for the beer brewing industry owing to the complexity of the beer foam matrix, its changing foaming properties over time, and interbatch variations in the product. Model foam standards proposed so far ignore the presence of foam-negative compounds. Response surface methodologies were applied to delimit the effects of components of foam standards (bovine serum albumin, ethanol, linoleic acid, and iso-α-bitter acids) on foam stability. Statistical analyses of experimental data were used to evaluate the significance of each component and their mutual interactions. The presence of linoleic acid in the foam standard was shown to be statistically important for foam stability and for interactions with individual components. A quadratic model was developed that describes alterations in foam stability as a result of changes in composition of foam standards, and this was validated by multiple measurements. A model beer foam solution can therefore be used as a reference in a brewing laboratory to validate methods of foam quality control and/or as a standard for foam research. Keywords: Beer foam, Model, Response surface methodology, Linoleic acid