J. Cosmet. Sci., 62, 525–533 (November/December 2011) 525 Freshness evaluation of refreshing creams: Infl uence of two types of peppermint oil and emulsion formulation SILVIA PEREZ DAMONTE, CLAUDIA SELEM, MARIA EMMA PARENTE, GASTÓN ARES, and ANA VICTORIA MANZONI, Proiectare Generación Cosmética, José Bonifacio 715, C.P. 1424, Caba, Argentina (S.P.D., C.S.), and Facultad de Química, Universidad de la República, Gral. Flores 2124, C.P. 11800, Montevideo, Uruguay (M.E.P., G.A., A.V.M.). Accepted for publication June 21, 2011. Synopsis The aim of the present work was to study the infl uence of emulsion composition and two types of peppermint oil (common and dementholated) on freshness perception (skin feel) of refreshing creams, as evaluated by trained assessors and two consumer panels. Both common peppermint oil (PO) and dementholated pepper- mint oil (DPO) were added in a 1% concentration to two base emulsions formulated with high (emulsion A) and low (emulsion B) concentration of apolar components. The samples’ freshness was evaluated by a panel of trained assessors and by consumers. Results showed that the freshness sensation was higher when formulation B was considered, which indicates that its low proportion of apolar components might have enhanced pep- permint oil liberation and penetration into the skin, increasing freshness perception. On the other hand, no signifi cant differences in freshness intensity after 5 min of application were found between creams formulated containing DPO or PO, suggesting that other components different from menthol might have contributed to the immediate perception of freshness. Results from the present work showed that emulsion formulation has a great effect on freshness perception, suggesting that different formulations should be considered and tested when developing refreshing cosmetics. INTRODUCTION Peppermint or Mentha piperita is a common herb, grown in Europe and North America, that is frequently used in cosmetic products as an odorant and refreshing agent (1,2). The plant contains about 1.5% essential oil. Menthol is the main component of the essential oil of peppermint (29% to 48%) and has been claimed to be mostly responsible for the oil’s refreshing properties (3,4). Menthol has been used as an odorant, as a fl avoring, and as a cooling agent (5). Menthol causes a fresh sensation some time after application and usually can lead to burning sensations when applied to the skin (6). The sensations perceived when Address all correspondence to Maria Emma Parente at mepr@adinet.com.uy.

JOURNAL OF COSMETIC SCIENCE 526 applying a refreshing agent to the skin or the mucous membranes depend on the con- centration of the agent. At low concentrations menthol might cause a fresh sensation, whereas at higher concentrations (2–5%) it might lead to irritation or local anesthe- sia, and at concentrations between 5% and 10% it could cause burning sensations (6). For this reason, dementholated peppermint oil (which has a lower concentration of menthol) could be an alternative to generate immediate freshness without uncomfort- able sensations. The use of dementholated peppermint oil has been also claimed to be cheaper. Despite the fact that dementholation is an extra processing step, this oil is usually sold at a lower price in Buenos Aires because of added value of the extracted pure menthol. In general terms, the freshness sensation on the skin depends on the refreshing agent, its concentration, and its ability to migrate from the product to the skin and to penetrate the stratum corneum (7). Therefore, the freshness sensation of a cosmetic cream depends both on the refreshing agent and the composition of the medium in which it is included. Peppermint oil is a lypophylic component and therefore is soluble in the oil phase of emulsions. When used in cosmetic emulsions, peppermint oil needs to be liberated from it in order to penetrate the skin. For this reason, a low solubility of peppermint oil in the oily phase or a low proportion of apolar components in the emulsion could enhance this process (6,8) and increase the freshness perception. In the last decade, sensory evaluation has become one of the most important tools in the substantiation of claims related to human perception of the characteristics of cosmetic products when applied to the skin. Sensory profi ling of cosmetic products is a powerful tool for the cosmetic industry as it provides relevant information for the development and marketing of new products, the reformulation of existing products, and the optimization of manufacturing processes (9,10). Traditionally, this methodology has been performed with a group of trained assessors who objectively provide a quantitative description of the sensory characteristics of products (9). In particular, Quantitative Descriptive Analysis with trained assessors has been widely used to study the sensory characteristics of cosmet- ics and cosmetic ingredients (11–15). On the other hand, consumer studies provide information about the consumers’ needs, expectations, and perceptions of product (11,16–21). For decades, consumers have been considered capable only of hedonic judgments (9,10). However, in order to assure the success of their products in the market, cosmetic companies also need information on how consumers perceive the sensory characteristics of their products. For this reason, descrip- tive analysis with consumers, i.e., asking consumers to rate the intensity of different sensory attributes, has received increasing attention in recent years and has been re- ported to be a good alternative to classical sensory profi les provided by trained assessors (22,23). Consumers’ perception is infl uenced by cultural and sociodemographic variables. Thus, cross-cultural studies could be extremely important and useful when devoloping cosmetic products for different international markets. The aims of the present work were to study: (a) the infl uence of emulsion composition and two types of peppermint oil (common and dementholated) on the freshness perception of refreshing creams as evaluated by trained assessors (n=6) and two separate consumer panels (n = 50+50), and (b) the infl uence of freshness on consumers’ liking of refreshing creams.