Dynamics of food preferences: a case study with chewing gums Julien Delarue * , El  eonore Loescher Laboratoire de Perception Sensorielle et Sensom etrie, Ecole Nationale Sup erieure des Industries Agricoles et Alimentaires, 1 avenue des olympiades, 91744 Massy Cedex, France Received 18 September 2003; accepted 17 November 2003 Available online 6 January 2004 Abstract The dynamics of food perception is critical in sensory science. However, although much research deals with time–intensity measurement as a tool for analytical sensory evaluation, it is striking that almost no published research investigates the dynamics of hedonic responses. Here we studied how consumers scored mint flavored sugar-free gums when the test duration varied. Six coated drag ee-like gums from the French market were tested by each consumer according to three test conditions: 1 min of chewing, 5 min and half-an-hour. One and five minute tests took place in the sensory lab evaluation booths whereas consumers were free to move about for the 30 min modality. All consumers thus participated to a total of 18 sessions. Our main finding is that the average liking varies with the test duration but that this variation differs for the six products in a way that one of the initially least liked products becomes the most liked when it is chewed during 30 min. Also, the individual liking patterns and the resulting consumer seg- mentation varied widely across the three test conditions. Additionally, a Flash profile was performed with experienced subjects in an attempt to relate the observed differences in liking to the gum sensory characteristics. Trigeminal-related sensations seem to play an important role in these changes. Clearly such aspects are to be taken into account for new product development and market analysis. This kind of concerns may be even more challenging for hedonic evaluation of many non-food products. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Dynamics of hedonic response; Test duration; Chewing gums; Consumer testing; Flash profile 1. Introduction The perception of a food during its consumption is obviously a dynamic process. Indeed, the food changes while we are eating or drinking. When placed in the mouth, it undergoes the combined action of saliva, chewing and breathing as well as temperature changes (Buettner, Beer, Hanning, Settles, & Schieberle, 2002; de Wijk, Engelen, & Prinz, 2003). This results in a pro- gressive texture breakdown (Brown & Braxton, 2000) and flavor release (Baek, Linforth, Blake, & Taylor, 1999; Guinard, Zoumas-Morse, Walchak, & Simpson, 1997; Wright, Sprunt, Smith, & Hills, 2003), two time- dependent characteristics of food. Together with these mechanical and physicochemical changes of the food bolus, consumers themselves are also prone to changes when eating or when drinking, also resulting in modifi- cations of the food perception. These changes may be due either to sensory adaptation (Dalton, 2000; The- unissen, Polet, Kroeze, & Schifferstein, 2000) or to a drift of attention linked to physiological and mood changes such as satiety, boredom, fatigue, etc. (Porch- erot & Issanchou, 1998; Rolls, Rolls, Rowe, & Sweeney, 1981). Time–intensity measurement methods were developed in order to record perceived intensity changes with time ðsee for example Cliff and Heymann (1993) and DeRovira (1996)Þ. Accordingly, we could expect an evolution of the liking for a given food product when it is eaten. Some researchers anticipated that consumer preferences could be explained by dynamic sensory data (Guinard et al., 1996; Hellemann, Barylko-Pikielna, & Matuszewska, 1990; Li, Marshall, Heymann, & Fer- nando, 1997; Noble, 1995). However, very little research focused on the temporal aspects of liking itself. Some attempts were made in the early 1990’s to record chan- ges in the degree of liking with time when subjects were sipping and swallowing a liquid (Lee, Barrick, & * Corresponding author. Tel.: +33-1-69-93-50-10; fax: +33-1-69-93- 51-74. E-mail address: delarue@ensia.inra.fr (J. Delarue). 0950-3293/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodqual.2003.11.005 Food Quality and Preference 15 (2004) 771–779 www.elsevier.com/locate/foodqual