2.2. Samples
Representation of final chocolate shapes and their names are
shown in Table 1. The shapes named Catstongue 1 and Catstongue 2
had very similar architectures; the former being longer and thinner
than the latter one.
To limit the study to the impact of the shape on in-mouth
perception, samples were made from the same recipe of dark
chocolate at 70% cocoa content and by using the same batch of
chocolate mass.
2.3. Sensory evaluation
Sensory tests were conducted with 12 trained female subjects
with an average age of 45 years old. They were screened for their
sensory abilities and had previous experience in descriptive evaluation
of foods. Training was provided so they were able to describe
and discriminate samples in a reliable way.
The two methodologies employed to characterise the products
and underline the sensory differences were:
Monadic profiling. This method gives a description of the
product’s in-mouth properties and allows quantifying the
intensity of each attribute. This static method was used as
a first step to identify the attributes that discriminate samples
and to select shapes that differed the most.
TimeeIntensity (TI). This dynamic methodology allows
following the evolution of the intensity of a single sensory
attribute over time. In the present study, TI was applied to
cocoa flavour to characterise, over time, the shapes that
differed the most according to the monadic profiling.
Subjects were instructed to let the chocolate melt in the mouth
and to avoid biting into it. Movement of tongue was not restricted
and subjects had the possibility to move the chocolate piece in the
mouth. The sensory glossary encompassing attributes, their defi-
nitions and their protocol of evaluation was agreed among subjects
(Table 2). For each of the samples, attributes were scored on
unstructured scales anchored from “weak” to “strong” (0e10). In
order to avoid carry-over effects and to ensure independent evaluations
of samples, subjects were requested to wait for 10 min
between samples and to clean their mouth by eating apple slices
and rinsing with bottled water.
In the timeeintensity experiment, subjects were instructed to
start the evaluation when putting the sample in the mouth by
clicking at the left anchor of the unstructured scale (“weak”). Then,
they scored continuously the cocoa flavour intensity over time by
moving horizontally the anchor on the intensity scale. The total
duration of the evaluation was set at 10 min, meaning that subjects
had to score the cocoa intensity even after the product had
completely melted and had been swallowed. Otherwise, test
conditions were unchanged from sensory profiling test.
For both evaluations, samples were delivered individually on
white plastic trays labelled with three digit codes. Samples were
stored at 20 C and evaluated at room temperature.
Sensory tests were carried out in individual sensory booths
designed according to the ISO 8589 standards (1988). A red light
was set up so that small differences in gloss due to the curvature of
the shapes were minimised.
In each test, samples were assessed twice and evaluated on
screen. The order of presentation of samples was balanced
according to a presentation plan based on Latin Squares.
Data acquisition of monadic profiling and timeeintensity tests
was done with Fizz software (Biosystèmes, Couternon, France). For
the timeeintensity test, the acquisition frequency was set at 2.6 s1
.