C. Adomat1, W. Brewer2, J. Ellert3, W. Poly4, B. Primmel5, H. Seidel6, S. Treibel5

1 Henkel / Phenion GmbH & Co KG
2 Sasol Germany
3 isi GmbH
4 Cognis
5 Beiersdorf AG
6 S. Black GmbH

Intention
For cosmetic products sensory characteristics are a decisive factor for consumer liking. How good a leave-on formulation can be distributed or how fast it permeates the skin will influence the consumer’s opinion on the product and his decision whether to buy the product again or not. While there are numerous examples for the use of correlation between descriptive and preference sensory data in food development, this tool is rarely used when developing cosmetic products.
The DGK (German Association for Cosmetics) section “Sensory” started a research project to assess different anti aging formulations systematically. In addition, together with the DGK section “Galenik”, efforts were made to explain some of the sensory parameters of a leave-on formulation by rheological measurements.

Approach
Eight leave-on formulations were included in a systematical three-step approach:

1. Measurement of the consumer acceptance
2. Measurement of the sensory perception by a trained expert panel
3. Instrumental measurements of rheological data

These differently gathered data sets were linked by multivariate calibration (PLS-regression) in order to show the interdependencies. Additionally, single parameters from the expert panel were correlated with the rheological data.

Results
By using this approach it was possible to reveal the key preference driving dimensions. The results showed which sensory parameters affect the acceptance of the anti aging formulations: The consumers prefer a rather fluid, oily texture with low cushion and low peaking. To develop more accepted formulations, the directions for improvement could be derived for six sensory dimensions. Additionally, the correlation between the sensory parameters and the rheological values delivered information for a pre-check of some sensory parameters of cosmetic products. With these findings, the product development gets hands-on knowledge which analytical measures dominantly influence the sensory perception of the important describing parameters.

The first research approach can be seen as a success and proves that a systematic correlation of different data sets provides more useful information than simply running consumer tests. Further steps need to incorporate other sensory dimensions like the odor of the anti-aging formulation as well. In addition the descriptive analysis and the consumer testing of the formulations might be carried out on the face as for this study the assessment has been made on the forearm.