NOTE Alginate Determination in Beer. H. B. Pfenninger, P. Anderegg, and E. Vykoukal, Swiss Brewing Research Institute, 8059, Zurich, Switzerland. J. Am. Soc. Brew. Chem. 41:0040, 1983.

Tests of a previously used colorimetric method for the determination of alginate in beer showed that the method was of no value. Using this method, we found significant amounts of alginate in beers produced in our pilot plant that had no alginate addition. Consequently, we devised a new procedure by which the alginate is converted into its barium salt and separated, followed by hydrolysis with hydrochloric acid. The resulting lactone of mannuronic acid is then detected by thin-layer chromatography. Because this method is very time-consuming, we attempted to devise a new procedure based on an electrophoretic separation. We tested different foils and gels as separating media, and varied the buffer solution and the pH value to achieve optimum separation. We also tried various staining techniques for the visualization of the separated alginate and determined the limit of detection.

Keywords: Alginate, Beer foam stabilizer, Electrophoresis, Thin-layer chromatography