Tara gum is obtained by grinding the endosperm of the seeds of the tara tree, Caesalpinia spinosa, which is native to and cultivated in the Cordillera region of South America. It is a galactomannan-type polysaccharide with a mannose-to-galactose ratio of 3:1.
In personal care products, tara gum functions as a multifunctional thickener and stabilizer, and also serves as a texturizing agent, delivering a smooth, non-sticky, and non-stringy feel. Its lower stickiness compared to xanthan gum may be attributed to its higher thickening efficiency, as smaller quantities are needed to achieve the same level of viscosity. Tara gum offers rapid hydration and strong resistance to electrolytes. Due to its non-ionic character, tara gum is compatible with both anionic and cationic ingredients.
In demineralized water, it forms a more viscous solution than xanthan gum at the same concentration, starting from around 0.8%. As the gum concentration increases, its viscosity rises sharply. At 1%, the viscosity reaches approximately 3000–6000 mPa·s, while at 1.5%, it exceeds 20,000 mPa·s. Different grades of tara gum vary in viscosity, but a general correlation between concentration and viscosity has been reported by Rigano et al.*
The viscosity of a tara gum solution in water is influenced by the processing conditions. Notably, solutions prepared with heat demonstrate significantly higher viscosity than those produced using a cold method. When prepared using hot and cold methods, a 1% solution exhibits viscosities of 5200–6000 mPas and 3000–4000 mPas, respectively.
* Rigano, L.; Deola, M.; Zaccariotto, F.; Colleoni, T.; Lionetti, N. A New Gelling Agent and Rheology Modifier in Cosmetics: Caesalpinia spinosa Gum. Cosmetics 2019, 6, 34.
