Dietary fiber content and composition of some cultivated edible mushroom fruiting bodies and mycelia

The mycelia and the caps and stalks of fruiting bodies of four edible mushrooms (Lentinus edodes, Lycophyllum shimeji, Pleurotus sajor-caju, and Volvariella volvacea) were analyzed for their total dietary fiber (TDF) content according to the Association of Official Analytical Chemists (AOAC) method and for TDF content and composition according to the Uppsala method. The nonprotein nitrogen attributable to chitin was corrected in the fiber residue obtained with the AOAC method. The TDF contents of all of the mushrooms as measured by the AOAC method were considerably greater than those determined by using the Uppsala method. Mushroom mycelia had higher TDF values than did the fruiting bodies as measured by both methods. The TDF composition of the mycelia and the TDF composition of the caps and stalks of the mushroom fruiting bodies were similar. Sugar composition reflected that beta-glucans were the major fiber polysaccharide with chitin, hemicelluloses, and polyuronides as minor ones. Notably, one-third of the total sugar in the TDF of the mycelium of L. shimeji was galactose.