Science of Sensory Analysis Measuring Flavour

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Science of Sensory AnalysisMeasuring Flavour

• John R. Piggott
• Strathclyde Institute of Pharmacy and Biomedical
  Sciences
• University of Strathclyde
• Glasgow
• Scotland
• j.r.piggott_at_strath.ac.uk

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What is flavour?

• Perception of the flavour arises from integration
  or interplay of signals produced as a consequence
  of sensing aroma, taste and chemesthesis from a
  food or beverage (Laing et al., 1996)
• The psychological interpretation of a
  physiological response to a physical stimulus
  (Noble, 1996)

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Flavour is

• Flavour is an interaction of food and
  consumer (von Sydow, 1971)
• Therefore sensory methods must be used to measure
  flavour (and all other sensory characteristics)
• However, physical/chemical methods, if properly
  validated by sensory tests, are often cheaper and
  more efficient

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The Human Senses

• Traditionally five senses
• Sight Visual
• Hearing Auditory
• Taste Gustatory
• Smell Olfactory
• Touch Cutaneous
• Touch can be divided into many separate systems
  or modalities

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Sight

• Stimulus radiant energy of wavelength 10-6
  to 10-7 m (visible light)
• Receptor rods and cones in retina
• Experience hue, brightness

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Hearing

• Stimulus mechanical vibrations of 20 -
  20,000 Hz
• Receptor hair cells in Organ of Corti
• Experience pitch, loudness

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Taste

• Stimulus chemicals in liquid solution
• Receptor taste buds
• Experience tastes (sweet, salt, sour, bitter)

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Smell

• Stimulus chemicals in gaseous solution
• Receptor olfactory cells in upper nasal
  cavity
• Experience odour

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Touch

• Stimulus mechanical pressure
• Receptor cells in skin
• Experience contact

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Touch temperature

• Stimulus temperature changes
• Receptor cells in skin
• Experience warmth, cold

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Touch pain

• Stimulus extreme energy of any kind
• Receptor free nerve endings
• Experience pain

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Kinesthetic sense

• Stimulus mechanical pressure
• Receptor cells in tendons, muscles, joints
• Experience movement

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Vestibular

• Stimulus movement of head
• Receptor cells in semi-circular canals
• Experience balance, equilibrium

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Organic

• Stimulus chemical or mechanical action
• Receptor cells in viscera
• Experience pressure, visceral disturbance
  (hunger, nausea)

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Taste

• Simpler response than smell
• A small number of basic tastes

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Basic tastes

• Sweet sugars
• Salt sodium chloride
• Sour acids
• Bitter quinine, caffeine
• Umami mono-sodium glutamate
• Other oral sensations
• Spiciness - not really a taste
• Astringency - not really a taste

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Smell

• No agreed primary odours (basic smells)
• Molecular work suggests several hundred
  receptors

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Flavour release in the mouth
Odour perception
Respiratory air flow
Taste perception
Adsorption
Partition equilibrium
B
c
A
Delahunty et al., 1996
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Sensory analysis

• a scientific method used to evoke, measure,
  analyze, and interpret those responses to
  products as perceived through the senses of
  sight, smell, touch, taste, and hearing (Lawless
  Heymann, 1998)

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Sensory analysis is

• about using a group of trained tasters,
• following a specified procedure,
• to tell you about the taste, smell, texture
• of a product sample

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Sensory analysis is not

• subjective
• about product experts
• about market or consumer research

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Sensory analysis can tell you

• what a product does (or does not) taste like
• Sensory analysis can not tell you
• whether your customers will like the product
• for that, you need to ask them

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Sensory analysis is

• trained tasters (assessors, panellists)
• Roughly speaking, the more the better
• Selected as competent
• being used as measuring instruments
• Unlike, say, a thermometer they can have opinions
• Procedures must be designed to eliminate the
  effect of their opinions

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Sensory analysis is

• specified procedure
• discrimination/difference tests
• descriptive analysis
• affective/hedonic test methods

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Discrimination/difference tests

• Are these two samples different?
• Unfortunately that question does not work
• Is this batch different from the usual?
• Will the customers notice that it is different?
• Does the difference matter?

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Descriptive analysis

• What do these samples taste like?
• How salty (sour, pungent, ) are they?
• How are they different?
• How is my product different from others on the
  market?
• What do the customers want?

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Measuring and scaling

• Anyone can measure the strength of a taste or
  smell,
• if they know exactly what it is
• People are (generally) good at tastes and colours

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(No Transcript)
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Affective/hedonic methods

• Do you like this?
• How much do you like it?
• Which of these do you prefer?
• Market segmentation different products for
• Different people
• Different uses

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Flavour profile demonstration

• Describe the orange juice samples
• Use some or all the words suggested, or add your
  own
• Words you use must be used for all the samples
• Score each word, for each sample, from 0 (absent)
  to 5 (very much)
• Do the samples in random order
• not 1 6 or 6 1
• My statistics will then try to make sense of it