A methodology, particularly well adapted to the evaluation of cosmetic creams containing various texturing agents, is defined here using the Spectrum Descriptive Analysis method. The objectives were to describe and to understand the contributions of the texturing agents to the texture attributes of oil-in-water emulsions. The study focused on eight hydrophilic polymers, either natural (e.g., xanthan), semi-synthetic (e.g., hydroxypropyl guar) or synthetic (e.g., carbomer), incorporated each one in an o/w emulsion. Eight texture attributes were selected and precisely defined, with strict evaluation procedures and notation scales. These attributes were gloss, integrity of shape, penetration and compression forces, stringiness, difficulty of spreading, absorbency and stickiness. A quantitative frame of reference was also developed. The methodology accuracy was evaluated through statistical analysis thus proving the sensory panel was highly discriminative, reproducible and repetitive. Principal component analysis underlined that polymers conferred to creams a very different skin feel when compared to the “control” emulsion without polymer. Synthetic polymers were characterized by higher consistency and lower gloss; semi-synthetic polymers and xanthan by higher degrees of stringiness, whereas carob exhibited intermediate properties.
This study may concern all the actors of the cosmetic industry, either the marketing, the quality control or the research and development departments. The developed methodology with precise definitions, strict and reproducible protocols, and with a frame of reference will be an accurate and useful tool to improve or optimize sensory evaluations of cosmetic creams, especially to investigate all the sensory aspects conferred to products by texturing agents. In the present study, the eight polymers were chosen as frequently used in cosmetic applications. As a consequence, both the methodology and the results are precious tools for product development and product optimization in order to meet consumers' texture quality requirements.