Properties of aqueous solutions of lentinan in the absence and presence of zwitterionic surfactants

Morphological and conformational transitions of lentinan (LT), a β-glucan extracted from Shiitake mushrooms (Lentinula edodes), were investigated at different concentrations of aqueous NaOH, using Small Angle X-ray Scattering (SAXS) technique. At low NaOH(aq) concentration LT chains are self-associated and adopt the triple helix form where as at higher NaOH concentrations the polymer chains undergo a transition to random coil chains. Also, the presence of fractal dimensions was observed through analysis of the exponential decay of the scattering intensity as a function of the scattering angle. In addition, the lateral radius of gyration was determined for LT in different concentrations of NaOH solution, indicating a rigid triple helix present as a small rod-like structure. Interactions of LT with two zwitterionic surfactants were investigated by surface tension, fluorescence, and static light scattering measurements. Experimental data showed that the formation of LT-(surfactant) complexes occurred through a cooperative process.