Effect of aroma quality on ad libitum food intake at different viscosities

It is commonly known that the problems concerning obesity and overconsumption
are increasing. Highly satiating products that induce an early meal termination
might be one of the solutions to fight obesity. During food consumption the
first processes that play a role are sensory processes and these are suggested
to play a role in the decision to terminate a meal.
From literature and non published results it is known that ad libitum food
intake and satiation feelings can be altered by manipulating the aroma
delivery. This study focuses on the investigation of the influence of the
quality of the aroma on the ad libitum food intake at two different
viscosities. With aroma quality we mean type of flavour like for example
strawberry, tomato or chocolate.
Much of our knowledge about food is acquired incidentally. This knowledge
guides food choices and food intake. Some aroma*s are very common in products
with a high energy density and therefore also associated due to learning with
energy dense products, while other aroma*s are common mostly in low energy
dense products. We hypothesize that aroma*s associated with energy dense
products increase satiation and accordingly decreases consumption, in
comparison with aroma*s associated with low energy dense products.
Also multimodal integration between the aroma and viscosity might increase
satiation and decrease food intake. Multimodal integration is the enhancement
of sensory signals when congruent stimuli from different sensory modalities are
being perceived. Because both creaminess and thickness are being associated
with more calories, we expect an enhanced satiation when these stimuli are
combined in one product. Therefore, we hypothesize that adding creamy notes to
a thicker tomato soup will increase satiation and decrease food intake more
than when adding creamy notes to a thinner tomato soup.

Primary Objective:
Investigation of the effect of the quality of aroma on ad libitum food
consumption, taking into account the multimodal integration between aroma and
viscosity.

Secondary Objective(s):
Investigation of the effect of viscosity on ad libitum food consumption,
independent of eating rate and eating effort.
Investigation of the effect of the quality of aroma on several food choice
parameters, namely explicit liking, explicit wanting, implicit wanting and
forced choice, taking into account the multimodal integration between aroma and
viscosity.
Investigation of the effect of the quality of aroma during ad libitum intake on
self-reported ratings (fullness, satiation, hunger, thirst, desire to eat,
appetite for something savoury, appetite for something sweet and pleasantness
of eaten food product) , taking into account the multimodal integration between
aroma and viscosity.

50 participants are recruited to participate in this study. They have to come 5
times to the test location during 5 separate test days with a minimum time span
of 5 days.

On each test day participants:
1. have to rate the liking and wanting of 16 food products shown on pictures
and choose 120 times between two food products on pictures (before and after
the ad libitum intake)
2. have to rate fullness, satiation, hunger, thirst, desire to eat, appetite
for something savoury, appetite for something sweet and pleasantness of eaten
food product (11 times during the experiment)
3. have to consume the test food to satiation, while the aroma is delivered
retronasally through a suction catheter that is connected to an Olfactometer.
During this part of the test the participants receive instructions on a
computer screen telling them about the moment when the soup is pumped into
their mouth (by a peristaltic pump), when to swallow and when to fill in
questions.

In this study 4 different test conditions will be compared against each other.
They differ in the quality of the aroma that is delivered to the nasal cavity
with the Olfactometer (with and without cremy notes) and in viscosity (low,
high).

The conditions will be randomised across all subjects in a within-subject
crossover design.

Intervention with aroma. Test condition without creme aroma and low viscosity
is placebo.

The study is non-therapeutic to the participant. This risk associated with
participation is negligble. Compared to other studies the burden can be
considered medium because of the invasive suction catheter and nose spray that
could result in stress and a running nose. A minor risk of the insertation of
the suction catheter to the nasal cavitity is nose bleed.