Chemical Structure and Rheological Properties of Tara Polysaccharide Gum

Tara gum is a natural hydrocolloid obtained by a mechanical process from the endosperm of tara tree seeds. In this study, chemical composition and structure of tara polysaccharide gum were characterized by Fourier transform infrared spectroscopy (FT-IR) and gas chromatogaph-mass spectrometer (GC-MS). Its rheological properties were also discussed. The results showed that tara gum had typical characteristics of plant polysaccharides, which was mainly consisted of galactose and mannose (mass ratio of galactose/mannose was 4.2:1), as well as a small amount of arabinose, glucose and xylose. The viscosity of tara gum solution increased with the increase of its concentration. The tara gum solution demonstrated a higher viscosity at the shear rate lower than 80 Hz, but a higher elasticity at the shear rate higher than 80 Hz.