Abstract

In this work by means of alkaline hydrolysis, the extraction of alcayota gum from Cucurbita ficifolia was carried out. The gum is purified by hydroalcoholic precipitations. This rubber is characterized by measurements of viscositydensity, Dynamic Light Scattering (DLS), and rheological. The intrinsic viscosity of the gum was 149.83 cm³/g and the molecular weight of 1867 kDa (whose Mark-Houwink parameters were k=0.00263 and a=0.7583), a shape factor of 3.12 and a hydration value of 47.63 g/g. From DLS the hydrodynamic radius was determined with a value of 53 nm, a molecular weight of 1722 kDa and with Mark-Houwink parameters of aD=0.5998 and kD=0.002543. The studies carried out for CyOH(d) showed a thixotropic behavior for the dispersed solutions that increased with the increase in hydrolysis and glycerin and decreased with the increase in temperature. The degree of thixotropy is higher for CyOH(d) compared to Cy(d). This polysaccharide can be applied in the film forming technology, as a thickening agent, etc.

Keywords: Cucurbita ficifolia; Gum; Polysaccharide; Dynamic light scattering; Intrinsic viscosity; Molecular weight