[Quantitative determination of some thickeners in dairy products (author's transl)]

An analytical method is described, by which nine polysaccharides used as thickeners for dairy products (locust bean gum, guar, gum arabic, tragacanth, arabinogalactan, carrageenan, furcellaran, agar, xanthan) can be identified in foods relatively rapidly and at the same time determined quantitatively. In this procedure interfering substances like fat, starch, proteins, sugars and salts are removed, the isolated polysaccharides are hydrolysed by trifluoroacetic acid and the monosaccharides resulting are measured by g.l.c. as aldonitrileacetates. The quantitative evaluation of the gas chromatograms is made by means of an internal standard and the content of thickener in the sample is calculated from one of the sugars. Recoveries of 80--90% with relative standard deviations of 5--10% were obtained when adding 0,05% of the thickeners to skim milk or 1--2% to mixtures of ice cream or pudding constituents.