Adulteration identification of some fungal polysaccharides with SEM, XRD, IR and optical rotation: A primary approach

Edible mushrooms have been consumed in Asian countries for healthy functions historically with polysaccharides, which have been manufactured as ending products, as one of the major bioactive components. Driven by profits, some inglorious manufacturers conducted adulteration using cheap carbohydrates. The extracted polysaccharides from Agaricus blazei Murill, Ganoderma lucidum and Lentinus edodes were chosen as products and maltodextrin, carboxymethyl cellulose (CMC), water soluble corn starch and guar gum as adulterants for adulteration investigation. Scanning electron microscope (SEM) observation implied regular granular shapes of fungal polysaccharides different significantly from the adulterants. Infrared spectra revealed alpha- and beta-anomeric types of polysaccharides and carbohydrates. X-ray diffractometry (XRD) suggested different diffraction patterns of polysaccharides from adulterant carbohydrates, the former were amorphous while the later somewhat crystalline of different crystallinity. Chiral properties of polysaccharides and carbohydrates showed big differences in specific rotation with good correlation between the content of "pure" fungal polysaccharides and adulterants. (c) 2009 Published by Elsevier Ltd.