A morphological examination was made of the tissues of jelly fig with a scanning electron microscope, and the rheological properties of sols and gels of the aqueous polysaccharides prepared from jelly fig were studied. SEM observation revealed a pectin-type polysaccharide layer on the surface of the seed and tepal of jelly fig.
The viscosity of the extracted solution from the tepal was higher than that from the seed, their flow behavior being characteristic of a polyelectrolyte with maximal viscosity at pH 3. The static viscoelasticity was measured with a 2% jelly fig gel, which could be represented by a six-element mechanical model consisting of a Hookean body, two pairs of Voigt bodies and a Newtonian body. The elasticity and viscosity percentages in the gel tended to decrease with increasing storage time. The dynamic viscoelasticity as a function of frequency, time and temperature was measured with a 3% jelly fig gel, the storage modulus (G′) and loss modulus (G″) being obtained in a range from 1 to 10² N/m². The value of the mechanical loss tangent (G″/G′) of the gel decreased with decreasing temperature, and remained constant below 20°C.