Measuring the feeling: Correlations of sensorial to instrumental analyses of cosmetic products

Abstract

Sensory features of cosmetic products are one of their most important characteristics for consumer acceptance. Consumers preferably choose one product among many based on their perceptions: first of its packaging, and then of its smell, appearance and texture (touch and feel). When optimizing a product, in order to adapt it to the needs and desires of consumers, cosmetic companies use sensory evaluation methods. They require trained panels making them time-consuming and expensive. On the other hand, rheological measurements and textural analysis are instrumental methods that offer fairly simpler, less expensive and much less time-consuming means of analysis, at the same time giving more objective and repeatable results. Finding correlations between sensorial assessments and instrumental analyses, and being able to use instrumental instead of sensorial analyses would have great benefits in the development of cosmetic products. However, this is not an easily accomplished task. In the available literature there are examples of these kind of studies on cosmetic emulsion systems (creams and lotions), but also on gels, foundations and raw materials. The prediction models are rarely developed and validated for having instrumental in lieu of sensory assessments. These studies are very versatile in terms of chosen sensory attributes and, even more so, in terms of studied instrumental methods and chosen parameters. Therefore, it is very difficult to compare them and find matching correlations. As sensorial analyses are being developed and new instrumental analytical techniques introduced with supporting sophisticated softwares, the number of studied parameters increases and new correlations are being made. It is still a worthy goal, however, to be able to instrumentally predict at least basic sensations associated with the use of cosmetic products to be used for screening in developmental phases of their making.