Children were tested individually following a 1-hour fast in a closed room designed specifically for sensory testing. Using methods embedded in the context of games and developed to meet the communicative, cognitive and behavioral capacities of pediatric populations, we phenotyped children in three ways. First, we determined the level (intensity) of sweetness preferred by using a forced-choice tracking technique [41,42], which has been shown to be related to the intensity of sweetness children prefer in cereals and beverages in the real world [31]. In brief, subjects were presented with pairs of solutions that differed in sucrose concentration (3%, 6%, 12%, 24%, 36% wt/vol). Subjects tasted, without swallowing, each solution and then pointed to which of the pair they liked better. The procedure continued until the subject either chose a given concentration of sucrose when it was paired with both a higher and a lower concentration or chose the solution with the highest or lowest concentration two consecutive times. We then repeated the entire task and used the geometric mean of the two chosen sucrose concentrations as the intensity of sucrose most preferred (‘sucrose preference’).
