Optimised quantification method for yeast-derived 1,3-β-d-glucan and α-d-mannan

The polysaccharides 1,3-β-d-glucan and α-d-mannan show numerous beneficial effects for the health of humans and animals. For several years, an increasing number of glucan- and mannan-containing products intended for food and feed applications are commercially available. For the determination of glucan and mannan contents, however, widely accepted methods have not yet been established. We have developed a practicable and reliable quantification method characterised by acidic hydrolysis with trifluoroacetic acid and subsequent determination of released d-glucose and d-mannose. The unavoidable loss of the monosaccharides due to the acidic conditions was minimised by optimisation of the hydrolysis parameters. The best conditions found were compared with literature methods in order to demonstrate the suitability. Finally, glucan and mannan contents of various commercial products were determined and compared to the specifications given by the manufacturers.