J. HORT (1), C. Rebecca (1), S. Francis (2), K. Smart (3); (1)
University of Nottingham, Loughborough, U.K.; (2) University of
Nottingham, Nottingham, U.K.; (3) SABMiller, Woking, U.K.
Sensory I
Wednesday, June 4 - 10:00 a.m.-11:45 a.m.
Level 4, Red Lacquer Ballroom
Although the effect of individual components on beer quality is
understood, limited knowledge exists concerning interactions between
different sensory stimuli. Carbonation presents an interesting and
challenging factor for investigation as it activates multiple sensory
modalities, and there is growing evidence that sensitivity to
carbonation varies within the population. This presentation links two
studies: one investigating the impact of carbonation on flavor
perception and a brain imaging (functional magnetic resonance imaging
[fMRI]) study exploring variation in response to carbonation across
individuals. A model beer, systematically varied in terms of sweetener,
hop acid, ethanol content, and CO2 level was developed and profiled by a trained panel (n
= 10) following quantitative descriptive analysis methods. Attributes
were generated encompassing flavor, taste, mouthfeel, and aftertaste
that described and discriminated between the samples. A D-optimal
experimental design was employed to reduce the number of samples (n = 31) evaluated while generating robust predictive models. Not surprisingly CO2
level was shown to impact tingling and carbonation, but there were also
effects on warming, bitterness, sweetness, and complexity of flavor (P
< 0.05), some of which were dependent on ethanol and hop acid level.
In the second study a less complex sweetened system, varying in
carbonation level, was evaluated by subjects (n = 24) for
carbonation intensity and liking. Subjects assessed these attributes
while simultaneously undergoing fMRI, using a Philips 3T scanner with
double echo and EPI acquisition, to assess their cortical response.
Subjects were previously screened for PROP (6-n-propylthiouracil) and
thermal taster status. PROP tasters are individuals more sensitive to
the bitter compound PROP but also other oral stimuli. Thermal tasters, a
relatively new phenotype, account for approximately 30% of the
population and are individuals who perceive “taste” from thermal
stimulation of the tongue, but who are also reported to be more
sensitive to some oral stimuli. Results showed that PROP and thermal
tasters demonstrated significantly increased cortical response to
increasing carbonation level and were more able to discriminate between
the different levels of carbonation compared to non-tasters.
Interestingly the thermal tasters least preferred the carbonated
samples, indicating that their increased sensitivity could impact liking
for this important attribute in beer and related attributes. The
combined results of these studies not only highlight the impact that
changes in carbonation can have on the whole sensory profile of a beer
but that perception of these differences varies across different
phenotypes and may well lead to considerable variation in beer
acceptability. Further research is now needed to evaluate the effect of
carbonation on sensory perception and acceptability across different
phenotypes across beer consumers.
Joanne Hort is the SABMiller Chair in Sensory Science and head of
brewing science at the University of Nottingham (U.K.). Originally
Joanne established the Sensory Science Centre at the university, which
is internationally renowned for its sensory research and training. After
developing a passion to understand the complexity of beer flavor, she
is now applying her expertise to progress understanding concerning
multisensory interactions, individual variation, temporal changes in
flavor perception, and emotional responses to the sensory properties of
beer. Her multidisciplinary approach combines analytical, brain imaging,
and sensory techniques and provides a rich insight into beer flavor
perception. Joanne leads the Brewing Science group, which has an
international reputation for its brewing research and innovative
postgraduate training programs. Joanne sits on the editorial board for ASBC Journal, Food Quality and Preference, Chemosensory Perception, and Flavour.
She is a member of ASBC and IBD and Fellow of the Institute of Food
Science and Technology. She is the current chair of the European Sensory
Science Society and past chair of the UK Professional Food Sensory
Group.
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