Antioxidative activity of (1→3), (1→6)-β-D-glucan from Saccharomyces cerevisiae grown on different media

In many microorganisms, fungi and algae (1 -> 3), (1 -> 6)-beta-D-glucan can be found as cell wall polysaccharide. Various publications describe the strong positive influence of these glucans on the immune system comprising antibacterial, wound-healing and antitumour activities. Recently, it was found that (1 -> 3)-beta-D-glucan from the yeast Saccharomyces cerevisiae also exhibits antioxidative capabilities. In the present study, the antioxidative activity of glucan from the cell walls of S. cerevisiae grown on different media (wort, yeast-peptone-glucose, yeast-peptone-galactose) was investigated. Fermentation of the yeast took place on three different media. After fermentation the yeast was harvested and disrupted in a high-pressure homogeniser. Subsequently, glucan was extracted from the yeast cell walls by a procedure including a combination of hot water and enzymatic treatment. The level of (1 -> 3) (1 -> 6)-beta-D-glucan in the cell walls was analysed enzymatically. The antioxidant activity was determined by electron paramagnetic resonance (EPR) spectrometry, TEAC assay (Trolox equivalent antioxidant capacity) and an 'amperometric biosensor'. The results show significant differences in the glucan content of the cell walls and in their antioxidative activities depending on growth medium. However, glucan itself seems to have a low antioxidative activity in contrast to other cell wall fractions e.g. proteins. (c) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.