Dynamic sensory characterization of cosmetic creams during application using Temporal Check-All-That-Apply (TCATA) questions Lucía Boinbaser a , María Emma Parente a , John C. Castura b , Gastón Ares c,⇑ a Cátedra de Química Cosmética, Departamento de Ciencias Farmacéuticas, Facultad de Química, Universidad de la República, General Flores 2124, C.P. 11800 Montevideo, Uruguay b Compusense Inc., 255 Speedvale Ave. W., Guelph, Ontario N1H 1C5, Canada c Facultad de Química, Universidad de la República, General Flores 2124, C.P. 11800 Montevideo, Uruguay article info Article history: Received 17 February 2015 Received in revised form 19 May 2015 Accepted 19 May 2015 Available online 21 May 2015 Keywords: Temporal Check-All-That-Apply questions TCATA Cosmetic creams CATA questions abstract The evolution of sensory characteristics during the application of cosmetic creams has been long recog- nized as important. However, standard methodologies do not evaluate how sensory characteristics of products change during application, and do not determine the onset of specific sensations. In this manu- script, a new temporal methodology, Temporal Check-All-That-Apply (TCATA), is used to enable charac- terization of the dynamic sensory properties of cosmetic creams during application. Six cosmetic emulsions were evaluated by 22 semi-trained assessors in duplicate using TCATA. Nine sensory attributes were considered: sticky, difficult to spread, easy to spread, white residue, fresh, smooth, waxy, greasy, and oily. Data were analyzed using line plots, difference curves, and correspondence analysis. The temporal profiles of the products during application were determined and fitted expectations due to changes in their rheological properties, water evaporation, and absorption into the stratum corneum of the skin, which cause changes in the structure of the film of product left on the skin. Differences in the temporal profiles of the samples were identified and explained by differences in their formulations, which indi- cates the validity of the data collected using TCATA with semi-trained assessors. These results show the potential of TCATA for characterizing the dynamic sensory profile of cosmetic creams during applica- tion, which opens new possibilities to sensory characterization of other cosmetic products. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction Skin care products are designed to provide a wide range of ben- efits on the skin, including cleansing, moisturizing, nourishing, pre- serving skin barrier function, and reducing the signs of aging (Abamba, 2000). Although these benefits are key determinants of the success of skin care products in the marketplace, their sensory characteristics are equally important (Wortel & Wiechers, 2000). Consumers are unlikely to use products if their sensory character- istics are unpleasant, even if they have a potential positive effect on their skin (Guest et al., 2013). For this reason, a large variety of ingredients are used to confer specific sensory characteristics to cosmetics in order to trigger pleasant sensations during and after application on the skin (Zocchi, 2009). The cosmetic industry is increasingly taking sensory characteristics into account when designing marketing and communication strategies for cosmetics, which makes sensory characterization a powerful tool (Giboreau, 2007; Stone & Sidel, 1986). Cosmetic products are usually designed to convey pleasant sen- sations during application (e.g. smoothness, freshness). However, unpleasant sensations can also be perceived as a consequence of product formulation (e.g. stickiness caused by some hydrocolloids and some protein hydrolysates, greasiness caused by petrolatum or hydrogenated oils), which in some specific situations are induced intentionally to show that the product is providing a benefit to the skin (e.g. roughness in exfoliating scrubs or heat in lipolytic creams) (Guest et al., 2013). Sensory characteristics commonly evaluated during product application include absorbency, cloudi- ness, freshness, greasiness, oiliness, roughness, silkiness, smooth- ness, spreadability, stickiness, thickness, tingling, viscosity, waxiness, warming, cooling, melting, wetness, tautness (ASTM, 2011; Guest, Mehrabyan, Essick, Hopkinson, & McGlone, 2012; Meilgaard, Civille, & Carr, 2000, chap. 11; Parente, Ares, & Manzoni, 2010; Stone & Sidel, 1986; Wortel & Wiechers, 2000). The sensory characteristics of skin care products during applica- tion depend on physicochemical properties of the film left on the skin and its interaction with the skin (Guest et al., 2013). These characteristics are time dependent and change during application due to several simultaneous processes: changes in rheological properties due to the shear exerted during application, evaporation http://dx.doi.org/10.1016/j.foodqual.2015.05.003 0950-3293/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: gares@fq.edu.uy (G. Ares). Food Quality and Preference 45 (2015) 33–40 Contents lists available at ScienceDirect Food Quality and Preference journal homepage: www.elsevier.com/locate/foodqual