Effect of oral sensory exposure on pork sensory specific satiety: a functional magnetic resonance imaging study

This study will employ a randomized, two way cross-over design. All participants act as their own control. Participants will be tested on two separate days (one week washout time in between) with one of two interventions: (1) A placebo chewing gum + standardized breakfast (2) A pork flavored chewing gum + standardized breakfast The flavour added to the pork flavored chewing gum related to a mixture of 2 pork ham flavours (5% Acorde JAMON1, 10% Acorde JAMON 2; Lucta SA, Montornes del Valles, Spain) , 5% monosodium glutamate (MSG) (Ajinomoto Inc., Japan), 0.05% inosine monophosphate (IMP, 4666803) and 0.05% guanosine monophosphate (GMP, 2421617) (Givaudan Australian Pty Ltd). This mimic real pork flavor (aroma and taste). The breakfast consisted of 100g pork (cooked ham), 125g boiled rice, 50g fresh apple and 200ml of pure water. The calculated nutritional content of the meal was 1309KJ, 21.8g of crude protein, 7.5g of total fat and 40.3g of carbohydrate. Pork was the predominant protein source. On the testing days, participants will arrive at the lab after an overnight fast, Participants will receive a chewing gum (either placebo or pork-flavored) and will be asked to chew for 7 min (chew rate between 25-30 times per min using a metronome) before they eat the breakfast. Participants will complete two brain scanning sessions: one baseline at arrival (pre-intervention) and the other one at 60 minutes after breakfast (post-intervention) with four categories of food cues (cake, meat, fruit and salad) shown as images alone or as combined image and congruent odors. Subjective ratings of food cues were measured during scanning as a measure of sensory specific satiety. Subjective specific appetite for sweet, savoury, fatty and salty foods were evaluated outside the scanner to test the transference of pork sensory specific satiety.