Instrumental prediction of in vivo sensory properties of emollients to allow the development of new biobased ingredients

Abstract

An important step in the development of novel cosmetic ingredients is the setting up of sensory analyses to assess their tactile properties. A recent work allowed the obtention of 12 novel biobased emollients with interesting physico-chemical properties. Four of the most promising emollients were selected in the present study and their safety was tested to ensure they are suitable for use on human skin. Their tactile properties, along with ten commercial emollients, were assessed by 16 expert assessors: circular spreading behavior, thickness of residual film and slippery after feel. In addition to characterizing a wide range of emollients, the results made possible the establishment of three predictive models using Partial Least Squares regressions. These original models correspond to various sensory attributes of the emollients, both during and after their application on the skin. All predictive models were then validated by leave-one-out cross validations. Only three instrumental parameters (viscosity, friction, stickiness) were necessary to build the models and predict the tactile properties. This approach was then applied to the eight other biobased emollients that were not initially used to establish the predictions in order to validate the models. Results demonstrate the significant value of such models for developing new ingredients. Ultimately, these predictive models could override the time-consuming and costly process of safety testing and sensory analyses in the research in development of future newly produced emollients for dermocosmetic applications.