Abstracts - Association for Chemoreception Sciences

#P227 POSTER SESSION V:
HUMAN TASTE PSYCHOPHYSICS;
OLFACTION RECEPTORS; TASTE DEVELOPMENT
#P228 POSTER SESSION V:
HUMAN TASTE PSYCHOPHYSICS;
OLFACTION RECEPTORS; TASTE DEVELOPMENT
TAS2R polymorphisms and the bitterness of RebaudiosideA
and RebaudiosideD
Alissa L. Allen 1 , John E. McGeary 2 , John E. Hayes 1
1
Department of Food Science, Penn State University Park, PA, USA,
2
Providence VA Medical Center Providence, RI, USA
With growing demand for natural non-nutritive sweeteners,
extracts from the Stevia rebaudiana Bertoni plant have become a
popular replacement for sugar. These exacts contain a mixture
of various taste active glycosides, with steviol being the most
abundant. The second most abundant glycoside is Rebaudioside
A (RebA). RebA (>98% pure) is a GRAS (generally recognized
as safe) ingredient in the United States, while stevia (the
mixed extract) is classified as a dietary supplement. Another
glycoside of interest is rebaudioside D (RebD), due to its high
dose response for sweetness and minimal bitterness relative to
steviol and RebA. Like saccharin and acesulfameK (AceK), the
bitterness from stevia glycosides varies across people. Previously,
variable saccharin/AceK bitterness has been associated with
single nucleotide polymorphisms (SNPs) in bitter receptor
genes (TAS2Rs). As part of an ongoing study, we explored
whether TAS2R SNPs may explain variable RebA and RebD
bitterness. After a brief orientation with bitter, sweet and metallic
training references, participants rated RebA, RebD, aspartame,
sucrose, and gentiobiose (a b 1-6 linked disaccharide) for these
sensations on a general Labeled Magnitude Scale. Salivary DNA
was obtained and genotyped via Sequenom MassARRAY. As
expected, mean RebD bitterness was much lower than RebA. In
preliminary analyses, RebA bitterness associated with a coding
SNP in TAS2R9 and a synonymous SNP in TAS2R50. For the
TAS2R9 Ala187Val SNP, Ala187 allele carriers reported less
bitterness than Val187 homozygotes. For RebD, the TAS2R50
SNP predicted bitterness, although this is likely a tag SNP for
another polymorphism given the synonymous substitution.
Finally, TAS2R31 SNPs previously shown to predict AceK
and saccharin bitterness did not predict bitterness from RebA
or RebD. Acknowledgements: Supported by funds from the
Pennsylvania State University and NIH grant DC0010904.
Sucrose analgesia and the cold pressor test in young men:
Methodological considerations
Rachel G Antenucci 1,2 , John Prescott 3 , Theresa L White 4 ,
John E Hayes 1,2
1
Department of Food Science, The Pennsylvania State University
University Park, PA, USA, 2 Sensory Evaluation Center, The
Pennsylvania State University University Park, PA, USA, 3 TasteMatters
Research & Consulting Sydney, Australia, 4 Department of Psychology,
LeMoyne College Syracuse, NY, USA
Sucrose is mildly analgesic in infant rats, human neonates, and
prepubertal children. This effect generalizes to non-nutritive
sweeteners, indicating the effect is due to sweet taste. However,
consistent sweet analgesia in adults remains elusive: some studies
find an effect while others do not. Pain can be safely induced
in the laboratory using the Cold Pressor Test (CPT), providing
a convenient means to study this phenomenon. It is unresolved
whether the inability to consistently observe analgesic effects in
adults is due to methodological issues associated with the CPT
or an age dependent effect. White and Prescott (AChemS, 2012)
reported strong order effects; tolerance was greater in the second
CPT within a session. They suggested rewarming the hand
between tests might reduce this bias. Here, we describe 2 studies
that attempt to refine an adult sweet analgesia CPT paradigm.
In study 1 (36 men), pain was induced by placing the dominant
hand in circulating water at 8 o C. Within a session, tastants were
water and 0.7M sucrose; participants were tested twice (fed /
fasted) in a double crossover design. The hand was rewarmed in
35 o C water between trials, and hand temperature was confirmed
with a laser thermometer. No tastant effect, regardless of hunger
state, was observed. However, a weak trend for an order effect
within a session was evident, despite rewarming. In study 2 (27
men), subjects received sucrose or water on separate days after an
overnight fast. The cold bath was reduced to 4 o C, and outcomes
included pain threshold (onset in s) and tolerance (hand
withdrawl in s). Pain thresholds and tolerance were greater on
day 2, but this occurred irrespective of tastant. Collectively, these
data suggest increased tolerance in the CPT with repeat exposure
is not an effect of initial hand temperature. Acknowledgements:
The Pennsylvania State University and USDA Hatch Act funds
POSTER PRESENTATIONS
Abstracts are printed as submitted by the author(s).
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