DOES EXPERIENCE HELP OUR NOSE CHANGES IN SENSORY

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DOES EXPERIENCE HELP OUR NOSE? CHANGES IN SENSORY
BRAIN RESPONSES ASSOCIATED WITH EXPERIENCE OF
ODOURS

• Caroline Owen, John Patterson,
• Damian Frank Rebecca Smith

Sensory Neuroscience Laboratory Swinburne
University of Technology
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Perception of flavour

• Complex combination of physiological responses.
• Olfactory system relatively direct and powerful
  connections to the areas of the brain associated
  with memory and emotion.
• Strong interaction between odours, associations
  and experience.
• cultural background, sociological factors
• emotional associations
• age, sex
• religious beliefs, ethical concerns, perceived
  healthfulness, etc.

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Olfaction experience

• To what degree does training or experience
  contribute to subjective and objective measures
  of flavour responses?
• Responses to odours flavours are not solely
  dependent on the persons ability to smell.
• The sense of smell is closely linked to memory
  and emotion and therefore to experiences.
• Decisions about flavours involve processing at
  very basic physiological levels, which can be
  independent of conscious awareness and then not
  able to be verbalised (which confuses consumer
  responses).

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Objective measures of odour responses

• Physiological monitoring techniques
• Objective measures of flavour responses.
• Independent of conscious flavour awareness.
• Not reliant on verbal communication.
• Complement subjective sensory measures.
• Technical development of novel delivery
  techniques.
• Close interaction with chemical analysis.
• ? Food beverage responses associated with
  experience.

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Comparison of objective vs sensory flavour
assessment
Subject groups
Comparison of brain activity with sensory ratings
(intensity, preference, descriptors)
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Beer odours experience

• Management of sensory properties of beverages to
• Maintain improve product quality.
• Develop products to meet consumer expectations.
• Tailoring products for domestic or export
  markets.
• Use chemical analysis, experienced, trained taste
  panels.
• ? How do the expert panel responses relate to the
  consumer expectations preferences?

• Industry Expert Panel 22 participants, all
  trained flavour panellists
• (18 m, 4 f aged 45.59 6.91 yrs, range 32 - 56
  yrs).
• Consumer Naive Panel 22 participants, all beer
  drinkers
• (16 m, 6 f aged 33.04 11.47, range 18 - 57 yrs).

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Olfactory profiling sensory ratings

• Significant rating differences between groups.
• Naïve Higher rating for Malty, Yeasty.
• Experts Higher rating for Soapy, Butterscotch.
• Experts stronger like for Light beer.
• Naïve stronger like for Heavy beer.

• Olfactory performance
• No significant differences
• Experts Trend for better discrimination.
• Naïve Trend for better identification.

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EEG responses to beer odours
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Beer odours experienceLike vs Neutral vs
Dislike

• Experts LF decrease in 8-12 Hz band (alpha) with
  Liking for Light beer.
• Naive LF increase in 8-12 Hz band (alpha) with
  Liking for Light beer.
• ? alpha ? increased attention.

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Beer odours experience

• Difference in expertise of industry subjects
  evident in subjective rating responses
• Differences between groups in Liking responses to
  Heavy Light beers.
• Naïve stronger association with Malty Yeasty
  descriptors
• Experts stronger association with Soapy
  Butterscotch descriptors.
• BUT differences in EEG responses not easily
  predicted as a consequence of training.
• Differences in processing evident in EEG between
  groups.

? Suggests that training and knowledge alter the
flavour experience, independent of olfactory
ability. ? Care needed in interpreting expert
responses in relation to the general consumer
population.
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Dairy odours experience

• Comparison of Australian vs Overseas flavour
  responses
• Heptanone p-cresol methional
  dimethyltrisulphide
• Australian n 18 (8 m, 10 f), aged 19-55 yrs,
  (mean 29.12yrs).
• Overseas n 28 (15 m, 13 f), aged 18 - 34 yrs,
  (mean 24.64 yrs).
• All completed EEG sessions (15 mins) to 4 odours.
• Dairy odour rating sessions (28 odours)

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Dairy odours experience

• Subjective Liking Strength ratings
• No significant between group differences
  (pgt0.05).
• Australian OS
• Liking Strength Liking Strength
• Methional Neutral Neutral Neutral Neutral
• Heptanone Neutral Strong Neutral Neutral
• p-cresol Neutral Neutral Neutral Neutral
• DMTD Dislike Neutral Dislike Neutral
• Comparative ranges in responses for both groups.
• Mean ratings for each individual suggested subtle
  differences in Liking between the Australian OS
  groups.

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Dairy odours experience
Moderately strong significant difference (plt0.05)
in 5-8 Hz (theta) responses. para-cresol (RF)
Australians OS M 0.36, SD 6.83
M -4.26, SD 7.15 Non-significant trends in
5-8 Hz responses heptanone (LF and
RF) Australians OS LF M 1.18, SD 5.11
M -2.30, SD 8.09 RF M 1.63, SD 4.15 M
-0.83, SD 11.17 DMTS (LF only) M0.86,
SD6.56 M -0.92, SD7.62).
Summary Australians - ? theta OS - ? theta
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Dairy odours experience

• EEG responses
• Differences evident in EEG responses, not
  observed in ratings.
• theta activity reflection of an odours ability
  to attract or distract
• Reflects changes in attention associated with the
  emotional hedonic odour responses.
• ? consistent with the utilisation of different
  physiological processes involved in the early
  sensory response to the odours.
• ? associated with differences in experience and
  the later subjective responses to these odours
  of differing familiarity.
• To test robustness of theta differences
• requires additional studies.
• larger subject groups.
• stronger ethnic and/or experiential focus.

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Conclusions

• Experience influences flavour perception -
  training and/or background
• Evident in sensory and objective physiological
  measures.
• Experts vs Naïve
• Australians vs Overseas
• EEG and sensory analysis of strength, liking and
  preference responses to assist in identifying
  flavour responses.
• ? Contribute to a basic understanding of flavour
  responses.
• ? Potential for sensitive language- and
  experience-independent measures to add depth to
  the flavour profiling of target groups for
  product development.
• ? Potential to develop products tailored to
  different markets.

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Acknowledgements
Carlton United Breweries
Dairy Research Development Corporation, Australi
an Cheese Technology Program

• Damian Frank (SNL) Chemical analysis and
  support.
• Rebecca Smith, Simon Danckert, Jo Fitzsimon EEG
  recordings and analysis (SNL).
• Tim Hendtlass Peter Cadusch - assistance with
  EEG analysis techniques.
• CRC for International Food Manufacture
  Packaging Science.