A new colorimetric method to quantify β-1,3-1,6-glucans in comparison with total β-1,3-glucans in edible mushrooms

Mushroom beta-glucans are known for their activity as biological response modifiers and anticarcinogenic agents. beta-1,3-1,6 Branched glucans with a triple helix tertiary structure are recognised as the most potent ones. In the present work, a colorimetric method for beta-1,3-1,6-glucan quantification based on the dye Congo red is introduced. This method is specific for beta-glucans with a triple helix. The beta-1,3-1,6-glucan content of mycelia and fruiting bodies from various mushrooms was determined and compared with the total beta-1,3-glucan content, measured by a fluorimetric method. The results show equal amounts of beta-1,3-1,6- and total beta-1,3-glucans in the analysed species but obvious differences between mycelia and fruiting bodies. On the average, 3% of mycelia and 8% of fruiting body dry mass consist of beta-1,3-1,6-glucans. The average percentage of beta-1,3-1,6-glucans in the total beta-1,3-glucan content differs between mycelia (46%) and fruiting bodies (87%). (C) 2011 Elsevier Ltd. All rights reserved.