476 JOURNAL OF COSMETIC SCIENCE
increase in mucilage viscosity. Hydrating the gum at a high temperature increases its
solubility and reduces the hydration time, which also leads to higher viscosity mucilage.
Because of its viscosity and nonionic characteristics, tara can be used as a rheology modifier
in conditioners with 0.3 wt% to 0.9 wt% of tara in a simple chassis as shown in Figure 25.
The results show an increase in viscosity and yield value with an increasing amount of
tara. The yield value provides an indication of the microstructure of the formula (lamellar
gel network),27 and the higher yield value typically results in a more stable system. The
stabilization of the lamellar structure of the emulsion formula was observed under a
microscope with polarized light when including tara was also demonstrated in internal
Figure 23. Viscosity, yield value, and turbidity within a sulfate-free chassis: 6.0 wt% alpha olefin sulfonate,
4.0 wt% cocamidopropyl betaine at pH 6.5. *Brookfield® (Brookfield Engineering Laboratories, Inc.,
Middleboro, MA, USA) viscosity at 20 rpm (mPa·s).
Figure 24. Effect of tara concentration and hydration temperature on mucilage viscosity.

477 DELIVERING SUSTAINABLE SOLUTIONS TO IMPROVE WELLBEING
studies. It is therefore easier to formulate when tara is included, ensuring stability while
providing the potential to cover a wide range of viscosities with a smooth texture, which
is a critical parameter for a satisfying consumer experience. Conditioner microstructure
is also key to high-performing conditioners.28 In agreement with the theory that a better
microstructure (higher yield value and lamellar gel network) leads to improved conditioning
performance, sensory analyses have demonstrated that tara (at 0.8 wt%) provides sensorial
benefits in conditioners as shown in Figure 26.
Figure 25. Effect of tara concentration in a hair conditioner (aqua, 0.3–0.9 wt% tara, 1.05 wt% cetrimonium
chloride (28%), 4.5 wt% cetearyl alcohol, 2.5 wt% mineral oil, 0.5 wt% sodium benzoate, and citric acid (adj.)
to pH 3.8–4.5).
Figure 26. Sensory rating comparison between a control, tara, and guar gum in a conditioner (aqua, 0.8
wt% tara, 0.5 wt% stearamidopropyl dimethylamine, 3 wt% cetearyl alcohol, 2 wt% cetearyl alcohol and
ceteareth-20, 4 wt% emollient, 5.2 wt% additives, and 0.5 wt% lactic acid, pH 4.0-4.5).