lecture 1

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LECTURE 01
WHAT IS SENSORY ANALYSIS?
Definition-1 
“Sensory analysis is the identification, 
scientific measurement, analysis and 
interpretation of the properties (attributes) 
of a product as they are perceived through 
the five senses of sight, smell, taste, touch, 
and hearing.” – Carpenter and others 2000. 
“Sensory evaluation has been defined as 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.” – IFT 
1975; Stone and Sidel 1993. 
Definition-2 
• To evoke –
– Guidelines: preparation & serving of samples 
– Under controlled conditions
– So that biasing factors are minimized
• To measure –
– Sensory evaluation: quantitative science
– Numerical data are collected 
– Establish lawful and specific relationships
– Between products and human perceptions
– Rely on techniques of behavioral research
– Observing and quantifying human responses
• To analyze –
– Proper analysis of the data is critical 
– Data of human observers might be variable
– Many sources of variation in a sensory test
• To interpret –
– A sensory evaluation is an experiment
– Useful when data interpreted in the context of
• hypotheses
• background knowledge
• implications for decisions/actions to be taken
• To interpret cont.
– Conclusions involve
• consideration of the method
• limitations of the experiment
• background and contextual framework of the study
– Sensory specialists must contribute to
• Interpretations
• suggest reasonable courses of action - results
• should be full partners with their clients
• the end users – in guiding further research 
Why should we use sensory analysis?
• Communication purpose partly
• Partly for decision making
• Product tasting – a daily occurrence
– Awareness: own & competitor’s products
– Promote company’s products to consumers
– Seek customer’s approval
– Demonstrate latest product range to sales
– Keep project team up to date on R&D
– Check if product quality matches specs
• The last 2 reasons – impacts decisions
– Follow/change line of R & D
– Whether to release product for distribution
• Should companies refrain from informal 
tastings, why? Pitfalls –
– The wrong objective
– The wrong questions
– Biased judgments
– Lack of scientific controls
– The wrong environment
Proper sensory testing to avoid the pitfalls…
• Setting the right objective –
– Lack guidelines, assessor training, references
– Subjective judgments made, inappropriately
• Asking the right questions –
– Informal tastings are not planned/structured
– Information collected might be ambiguous
– No structure to data collection
– The product picture might be incomplete
• Eliminating bias –
– Judgments might be biased – preconceptions
– Particularly if blind-testing is not done
– Vested interest may be there
– Opinions of dominant persons might be taken
– Serving order has to be randomized too
• Achieving scientific control
– Control over: sample size, comp, temp, timing
• Having the right environment
– Product presentation & tasting environment
– Distractions; odors; heat/cold; discomfort
Modern history of sensory analysis
• During the 1940s and 1950s
• US Army Quartermaster & Container Inst.
• Food acceptance for armed forces
• Importance of flavor/acceptability
• Forgotten by gov. in 1960s & 1970s
• “war on hunger” & “food from the sea”
• Scant attention to sensory evaluation
• Products unacceptable to target pop.
History cont.
• Industries began providing support
• Recognized its values in formulations
• Still minimal till the 1990s
• Early stages – experts were recruited
• Score cards were created for products
• 1957 – flavor profile by Arthur D. Little
• Qualitative DA – Dr. Jean Caul, K-State
• Had a panel (6-7), instead of the expert
History cont.
• UCDavis (1950s) started training scientists
• Other universities that started sensory:
– Oregon State University
– University of Massachusetts
– Rutgers
• Technical and scientific societies
– Committee E-18 of ASTM
– Food and Ag section of ACS
– Eur. Chemoreception Org.
– Sensory Eval. Div. of IFT
Central dogma – analytic vs. hedonic tests
• Test method should match objectives
• Communication between mgr & client/user
• Appropriate method, subjects, analyses
• E.g. DA – don’t ask preference Qs
• Consumers – don’t ask analytic Qs
“After a long and somewhat difficult 
gestation, sensory evaluation has 
emerged as a distinct, recognized 
scientific specialty”
Method Selection – Decision Tree 
 YES 
 
 
 NO 
 Go to panel setup 
 NO 
 
 
 YES 
 
 YES 
 
 
 NO Go to panel setup 
 
 
 YES 
 
 
 
 NO Go to panel setup 
 
 
 
 
 
 
 
Consumer 
Acceptability 
Question? 
Sensory Analytical 
Question? 
Choose from: 
Preference/choice; Rated Acceptability; 
Ranking; Just-right scales 
Question of whether 
products are 
different 
Probe issues –
need other test 
or approach? 
Question of how 
products differ, on a 
sensory basis? 
Probe issues –
need other test 
or approach? 
Choose from: 
Triangle; Duo-trio; Dual Standard; Paired Comparison; R-Index 
approach; Rated difference from control; Forced choice 
Choose from: 
Flavor profile; QDA approach; Spectrum method; Free-
choice profile; Hybrid 
What Qs does sensory analysis answer?
Classification of test methods in sensory evaluation 
Class Question of interests Type of test Panelist characteristics 
Discrimination Are products different in any 
way? 
Analytic Screened for sensory acuity, 
oriented to test method, 
sometimes trained 
Descriptive How do products differ in 
specific sensory characteristics? 
Analytic Screened for sensory acuity 
and motivation, trained or 
highly trained 
Affective How well are products liked or 
which products are preferred? 
Hedonic Screened for product use, 
untrained 
 
Discrimination 
• Is this product the same as that?
• Is this one different?
• How great is the difference?
• Would people notice the difference?
• Would people detect this taint?
• How many would discriminate/detect this 
difference?
Descriptive
• What does this product taste like?
• What are its perceived sensory 
characteristics/attributes?
• How does a change in 
process/formulation/packaging/storage 
conditions affect the sensory quality?
• How do these products differ from one another 
in sensory quality?
• For which sensory attributes are the 
differences most marked?
Preference/affective
• Do you like this product?
• How much do you like this product?
• Is it acceptable?
• Is it as good as this other product?
• Is this product better than that one?
• Do you prefer this one?
• What do you most like about this product?
• Which other features/attributes do you like?
Why collect sensory data?
• Human sensory data provide best models
• How consumers will react to products
• Sensory data collected for predictions
• How products have changed during dev.
• Four important factors in prod. dev
– Ingredients
– Processes– Packaging
– Shelf-stability (part of processing)
Why collect sensory data cont.
• Product manipulations – perceived diff.
• Involvement of psychophysics by humans
• Impinging on the sensory – physical
• The human response – psychological
• Sensory changes – unpredictable
• Sensory analysis – provides answers
• Answers about – own products
• Answers about – competitors products
• Important for survival of business
Sensory analysis is mainly used for –
Specifications and quality control
• What is the target specification?
• Does this product match the target spec?
• What variation in quality is to be expected? 
• What is the normal variation in each 
attribute?
• Is there a noticeable difference between this 
product and the reference standard?
Shelf-life studies
• How long can this product be stored before 
there is a noticeable change in the sensory 
qualities?
• How does the sensory quality change with 
storage?
• How long before the changes in sensory 
quality make the product unacceptable?
Taint potential – sources are in notes
• Is there a detectable difference in flavor/odor 
between product & standard?
• How would you describe this flavor/odor 
difference? 
• Is it foreign to the product – a taint?
• Is it detected immediately or in aftertaste?
• What proportion of the population detects this 
particular flavor/odor (taint)?
• How strong is the flavor/odor (taint)?
• How much does the flavor/odor (taint) affect 
the acceptability of the product?
Product Matching
Setting the target
• How is the ideal product/target described?
• What are the sensory attributes of the target 
product?
• What are the key sensory attributes needed to 
meet consumers’ expectations of this concept?
• What are the main sensory attributes affecting 
liking for this target product?
Comparing products with target
• Does this product match the target profile?
• Is this product sufficiently close to target?
• Is this product perceptibly different from the 
benchmark (target)?
• If the product differs, in what way does it 
differ? 
• How can it be made more like the target 
profile?
• Have these changes brought the product closer 
to target?
• Which of these products is closest to target?
Product reformulation
• If the recipe/process/pack were changed, how 
would quality be affected?
• Does this change make a noticeable diff.?
• Does this change cause the product to vary 
outside the normal range?
• By how much can the sensory characteristics 
be changed before liking for product is 
affected?
Product reformulation
• What are the sensory attributes of products 
already on the market?
• What are the key sensory differences within the 
range of commercial/ experimental products?
• What are the key attributes of the most and 
least successful products?
• How will a systematic change in formulation 
affect sensory quality?
Product reformulation cont.
• What further change in formulation is needed 
to achieve target sensory quality?
• Where are the gaps in the sensory map? 
• What product features does each gap 
represent? 
• Is this gap a new product opportunity? 
• What formulation and process would needed to 
fill this gap?
Product acceptability
• Which product is most liked/preferred?
• How much is this product liked?
• How much is the appearance/ flavor/ texture of 
this product liked/disliked?
• How much can this product be changed 
without affecting its liking/acceptability?
Some simple and golden rules for sensory 
analysis
• Be clear on test objectives
– Think about the possible outcome of a test
– Identify in advance the appropriate actions for 
each outcome (action standards)
• Do not make things too complicated for 
your assessors
– Break complex questions into a series of 
simple ones
– Do one test at a time to avoid bias and 
confusion
Rules cont.
• Ensure that your assessors are clear on their 
task and fully trained (if required)
• Design your test to minimize error and bias 
from assessors and products
• Create the best environment you can for the 
analysis
Rules cont.
• Minimize sources of error from product origin, 
preparation, and serving
– Carefully control timings, temperatures, portion 
sizes, and ingredient concentrations, e.g., salt, 
sugar, milk
• Do not try to assess too many samples at once
– Break them into small sets and provide rest periods 
in between.
• Know how to analyze and present your results 
for best effects
Sensory training for all food scientists?
• All food scientist should be familiar with 
concepts & methods of sensory analysis
• Continual challenge for sensory 
professionals to educate clients & execs.
• Methods poorly understood – mistaken for 
market research tests
• Violations of “central dogma” – common 
• Clients want hedonic judgments from 
trained or semi-trained panelists
• Conversely, they might want diagnostic data 
from consumers
• Over-interpretation of these inappropriate data 
are inevitable in such situations
• Training food scientists about the underlying 
concepts – to avoid misuse
• Mainly, conflicts between sensory 
professionals and execs./clients
• Conflicts arise due to short product timetables 
or limited resources
Sensory training for all food 
scientists? 
Food
Sensory
Scientist
Manufacturing
Research &
Development
Quality
Control Clients
Sales
MarketingCONSUMERS