26 WATERLESS FORMULATION
25 20 15 10 5 0 Wax Shampoo DP Shampoo Wax shampoo Figure 7: Solid shampoo - Texture analysis of the influence of HD dextrin palmitate on hardness
2. Makeup removing performance To verify the product performance, the makeup removing efficiency needed to be assessed. Compared to a benchmark of the same galenic (W/O) on a lipstick stain (Figure 6), the formulation with LD dextrin palmitate better dissolves the makeup and allows a more complete cleansing. This could be the result of emulsifying properties of LD dextrin palmitate.
3. Solid shampoo Many solid products tend to fall short of the wash performance target and leave a residue on the hair. It is therefore important to be able to compare the effectiveness of different formulas before putting them on the market. To study the effect of high-density (HD) dextrin
palmitate, two formulations were compared. One was the control formula called ‘Wax shampoo’
without HD dextrin palmitate. The other, called ‘DP shampoo’, contains HD dextrin palmitate in substitution of a part of the wax. The considered issues concerned the hardness of the shampoo and the foaming power. The role of the wax in this formula is to
participate to the solid texture, hence the hardness of the product. The comparison of the two formulations on Figure 7 shows that the ‘DP shampoo’ presents a higher hardness than the ‘Wax shampoo’. This result validates the substitution of 7% of the wax by HD dextrin palmitate, with the function of a consistency agent.
4. Foaming performance Three types of tests were carried out to evaluate the foaming performances of ‘Wax shampoo’ and ‘DP shampoo’. Firstly, as a prequalification for the Ross-Miles test, 1% w/w of each solid
Wax Shampoo ■ DP Shampoo ■
155 150 145 140 135 130 125 120
DP shampoo Figure 8: Prequalification for the Ross-Miles test
shampoo was added in deionised water in a test tube. The tube was shaken upside down for ten seconds. The results after one minute are presented in
Figure 8. Secondly, the Ross-Miles method was used to confirm the results when the developed formula showed interesting foaming effect (Figure 9). For both tests, the solution with the ‘DP shampoo’ have developed more foam than the ‘Wax shampoo’. Moreover, this gap was preserved after three minutes in the Ross-Miles test. Third, a protocol on hair strands was designed in order to provide an evaluation close to the consumer’s gestures (Figure 2). The test was performed on the two shampoo bars with and without HD dextrin palmitate. The protocol was repeated by five operators and the photo showing the quantity of foam produced at each step was compared by eight evaluators. A statistical ranking test showed that there was no difference between the two shampoos. The results obtained with the DP shampoo are illustrated in Figure 10. The first two tests showed that HD dextrin
palmitate increases and stabilizes the foam formed by the shampoo compared to a formula containing only wax. However, the usage test on the strands did not make it possible to discriminate between the products, perhaps due to a great variability among the operators.
After 1 min After 3 min
Figure 9: Solid shampoo - Evaluation of the influence of HD dextrin palmitate on foamability and the stability of the foam produced (Ross-Miles)
PERSONAL CARE January 2023
Conclusion To evaluate the influence of dextrin palmitate on the texture of these cosmetic products, their viscosity and hardness were measured using a rheometer and a texturometer, respectively. Moreover, a mixture experimental design was carried out on the makeup remover jelly. This approach characterised the minimum
concentration of dextrin palmitate required to ensure target hardness and highlighted the interaction effects between this gelling agent and the surfactant on apparent viscosity. In
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Volume of foam (mL)
Hardness (N)
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