RESUMO
BACKGROUND: Lipstick is currently one of the most sold products of cosmetics industry, and the competition between the various manufacturers is significant. Customers mainly seek products with high spreadability, especially long-lasting or long wear on the lips. Evaluation tests of cosmetics are usually performed by sensory analysis. This can then represent a considerable cost. OBJECTIVES: The object of this study was to develop a fast and simple test of delamination (objective method with calibrated instruments) and to interplay the obtained results with those of a discriminative sensory analysis (subjective method) in order to show the relevance of the instrumental test. METHODS: Three mid-range lipsticks were randomly chosen and were tested. They were made of compositions as described by the International Nomenclature of Cosmetic Ingredients (INCI). Instrumental characterization was performed by texture profile analysis and by a special delamination test. The sensory analysis was voluntarily conducted with an untrained panel as blind test to confirm or reverse the possible interplay. RESULTS: The two approaches or methods gave the same type of classification. The high-fat lipstick had the worst behaviour with the delamination test and the worst notation of the intensity of descriptors with the sensory analysis. CONCLUSION: There is a high correlation between the sensory analysis and the instrumental measurements in this study. The delamination test carried out should permit to quickly determine the lasting (screening test) and in consequence optimize the basic formula of lipsticks.
