Post on 17-Mar-2022
transcript
Methodological Report
WP2 Sensory Analysis Presentation Nelly FORESTIER-CHIRON, CIRAD, Montpellier, France
Christophe BUGAUD, CIRAD, France Isabelle MARAVAL, CIRAD, France
1
This report has been written in the framework of RTBfoods project.
To be cited as:
Nelly FORESTIER-CHIRON, Christophe BUGAUD, Isabelle MARAVAL. 2018. WP2 Sensory Analysis Presentation. Montpellier (France). RTBfoods Project Report, 80 p.
Image cover page © Dufour D. for RTBfoods.
© D. Dufour
Sensory analysis
labosenso@cirad.fr
Nelly Forestier-Chiron
Christophe Bugaud
Isabelle Maraval
Quality
Ability of a product to satisfy its users
Food quality has multiple components:
- Safety / hygiene & sanitary quality- Health / nutritional quality- Taste / organoleptic quality- Service / quality for use
3
Plan
I. What is sensory analysis: perception and measurement Some definitions Physiology of perception Sensory response
II. The various types of sensory tests Analytical (discriminative, descriptive) Hedonic
III. Drawing up a sensory profile: descriptive tests The working environment: the laboratory The panel Drawing up the protocol Preparing the questionnaires
IV. In practice ... Setting up a panel Recruitment General training Specific product training 5
Plan
I. What is sensory analysis: perception and measurement Some definitions Physiology of perception Sensory response
II. The various types of sensory tests Analytical (discriminative, descriptive) Hedonic
III. Drawing up a sensory profile: descriptive tests The working environment: the laboratory The panel Drawing up the protocol Preparing the questionnaires
IV. In practice ... Setting up a panel Recruitment General training Specific product training 6
I. What is sensory analysis:
perception and measurement
TOUCH
SMELL
SIGHTHEARING
TASTE
Sensory analysis is defined by ISO as the examination of theorganoleptic properties of a product by means of the sensory organs
= defining a relationship between stimulus and sensory perception
8
Visual
stimuli
Auditory
stimuli
Olfactory
stimuli
Gustatory
stimuli
Tactile
stimuli
I. What is sensory analysis:
perception and measurement
Shape (flat, round, etc.) Colour (yellow, dark, etc.)State (Liquid, Solid, Gaseous, etc.)Appearance (clear, cloudy, dull, shiny,etc.)
Softening, crunchiness, etc.
Volatile, spicy, floral substances, etc.
Primary tastes (sweet, salty,sour, bitter)Impressions / sensations (astringent,spicy, metallic, etc.)Aroma (fruity, floral, etc.)
Consistency, temperature, spongy, etc.→ Fruit maturation stage, cooked meat,etc.
9
Chewing rear nasal
+ saliva
I. What is sensory analysis:
perception and measurement
Some definitions (ISO)
Odour : emanation of volatilesubstances perceptible to(front nasal route)
the olfactory organ
Aroma : perceptible to the olfactory organ (rear nasal route) during tasting
Taste : sensations perceivedby the gustatory organ whenstimulated by certain solublesubstances
food in mouth
expulsion of volatile olfactorycompounds from matrix route cavity
10
Astringency : qualifies the complexsensation resulting from contraction of thesurface of the mouth's mucous membranes,produced by substances such as tannins frompersimmon, wine, etc.
TASTE
Flavour : complex set of olfactory and taste sensations perceived during tasting
AROMA
ODOUR
FLAVOUR
I. What is sensory analysis:
perception and measurement
Some definitions (ISO)
11
Taste perception
Diagram of the tongue
I. What is sensory analysis:
perception and measurement
Tactile sensitivity
Fungiform papilla
Filiform papilla
Calciform papilla
Bitter
Salty
Sweet
Sour
13
Tastes: examples
I. What is sensory analysis:
perception and measurement
• Sour : tartaric or citric acidLemon, orange, coca cola
• Bitter : caffeine or quinine hydrochlorideEndive, dark chocolate, coffee
• Salty : sodium chlorideCrisps
• Sweet : sucrose Sweets
The detection and recognition thresholds depend in particular on
dietary habits and training 14
I. What is sensory analysis:
perception and measurement
A scientific method!
The objective: define a relationship betweenstimulus and sensory perception
Not measurable by other methods
There is no standard observer
16
I. What is sensory analysis:
perception and measurement
What is it used for?
Research and development (formulation, comparison, development of new products, brand strategy, etc.)
Comparing qualitative and quantitative information
Quality control
Marketing / Consumer preferences
Guiding research
17
Receptors Nerve fibres Brain
stimulation Conscious ResponseBehaviour
I. What is sensory analysis:
perception and measurement
Physiology of perception
A FOOD emits a variety of information perceived bythe sensory organs:
these are STIMULI
Each sensory organ transforms a stimulus into a NERVE
IMPULSE which travels via the corresponding sensorynerve to be interpreted in the BRAIN
18
I. What is sensory analysis:
perception and measurement
Physiology of perception
1. Coding (quality, intensity)2. Integration: hedonic score (memory)3. Emotional + sensory message4. Verbalisation, quantification, aversion, preference
Sensory response
Spontaneously:1. Hedonic comment2. Qualitative comment3. Quantitative comment
Need for training to describe correctly, precisely and reproducibly 19
Sensory response
I. What is sensory analysis:
perception and measurement
The intensity of the sensation is a function of themagnitude of the stimulus
1 : subliminal, background noise
2 : liminal, unpredictable sensation (clear / confused), very low intensity
3 : supra-liminal, clear sensation, intensity varying from“weak” to “strong”
4 : saturation, sensation with practically no variation (possibility ofdiscomfort)
Value of stimulus
Inte
nsi
ty o
f se
nsa
tio
n
20
Psychological factors:- Appearance: pink-coloured yogurt, coloured white wine,brand, etc.
- Influence from neighbour: grimace- Sample presentation order (1st product)- Character (hesitant use of scale) fair
= good
fair= indifferent
I. What is sensory analysis:
perception and measurement
Sensory response
- Information on study
Sensory response is influenced by:
Physiological factors:- Ageusia, etc.- Persistence
21
I. What is sensory analysis:
perception and measurement
Sensory response
This is an interaction between the experimenter and the subject
Experimenter Sensory subjectstimulus
question
The question is essential22
Plan
I. What is sensory analysis: perception and measurement Some definitions Physiology of perception Sensory response
II. The various types of sensory tests Analytical (discriminative, descriptive) Hedonic
III. Drawing up a sensory profile: descriptive tests The working environment: the laboratory The panel Drawing up the protocol Preparing the questionnaires
IV. In practice ... Setting up a panel Recruitment General training Specific product training 23
II. The various types of sensory
tests
Two types of approach :
Analytical :
Discriminative or descriptive
Differences
Hedonic :
Refering to pleasant or unpleasant sensations
Preferences
25
II. The various types of sensory
tests
“Naive” subjects: unfamiliar with either the product or sensory analysis
Informed subjects: familiar with the product and sensory analysis
Qualified subjects: familiar with theproduct, sensory analysis, trained, monitored,approved,etc.
27
II. The various types of sensory
tests
Discriminative tests
Among the most commonly used tests: checking production consistency, consequences of a change in raw material, evaluation of modified appearance time during storage, etc.
Various types:
Duo/trio Triangular P out of nA not A
30
II. The various types of sensory
tests
Discriminative tests
Example: Which sample do you perceive as different from the other 2?
Judge 1:
A A B
Judge 2:
A B B
Is there a difference between 2products?
Triangular test
31
II. The various types of sensory
tests
Subjects- Around thirty- Monitor their results over time
Samples- 6 possible presentationsAAB, BAA, ABB, BAA, ABA, BAB- Use each presentation a similar number of times
otherwise risk of bias (random choice of middle sample,better identification of the most intense sample if it is doubled)
Processing:Number of correct responses and comparison with a 1/3 probability binomial distribution (cumulative probability, unilateral test)
Discriminative tests
32
II. The various types of sensory
tests
Discriminative tests
Advantages:- Easy to implement- Easy to take, even for untrained subjects- Fun (training)- Easy to interpret
Drawbacks:- Requires homogeneous products- High number of tests if there are a lot of samples- No indication on the nature of the difference
33
C < A < B
Descriptive tests
Ranking test
II. The various types of sensory
tests
Rank in increasing order of intensity for a specific characteristic of the samples presented simultaneously
Example: Which product is sweetest ?
35
II. The various types of sensory
tests
Descriptive tests
Advantages :- Easy to implement (no control or reference)- Easy to understand, even for untrained subjects- Easy to interpret- Indisputable in terms of theory (according to psychologists)- Effective
Drawbacks :- All the samples must be presented at the same time
difficulty in studying storage, for example- No indication as to intensity of the differences perceived- Potentially very high number of comparisons
36
Draw up a descriptive profileConventionalprofile
II. The various types of sensory
tests
Descriptive tests
Example: What are the organoleptic characteristics of a coffee?
Quantification of appropriate descriptors (established list or generating a list)
Objective: describe the product as briefly as possible
NB: no hedonic descriptors
Odour intensity
37
Free profile
II. The various types of sensory
tests
Descriptive tests
Each subject creates their own vocabulary
Training is easier
Statistical processing is complex
Interpretation of results takes much longer38
Plan
I. What is sensory analysis: perception and measurement Some definitions Physiology of perception Sensory response
II. The various types of sensory tests Analytical (discriminative, descriptive) Hedonic
III. Drawing up a sensory profile: descriptive tests The working environment: the laboratory The panel Drawing up the protocol Preparing the questionnaires
IV. In practice ... Setting up a panel Recruitment General training Specific product training 40
III. Drawing up a sensoryprofile: descriptive tests
The working environment: personnel(ISO 13300-1:2006)
Laboratory DirectorAdministrative and budgetary responsibility
Sensory AnalystScientific head of the analysis
Session TechnicianTechnical Manager → operational function
panel Coordinatormanages panel activities (organisation); recruits, trains and supervises the subjects
Quality Manager43
III. Drawing up a sensoryprofile: descriptive tests
The working environment: the room(ISO V 09-105)
Principle: constant conditions, controlled to reducedisruption and the effects that psychological and physicalconditions might have on human behaviour.
Minimum set-up:- a test room for working in booths or in a group- a preparation room
44
The working environment: the room(ISO V 09-105)
III. Drawing up a sensoryprofile: descriptive tests
45
III. Drawing up a sensoryprofile: descriptive tests
The working environment: the room(ISO V 09-105)
Temperature
Humidity
Uniform and controllable light
Floor, wall and ceilings easy to clean, odourless, soft and relaxing colour→ Room free from odours, ventilation
Layout preventing mutual influence (individual booths)
Silence46
III. Drawing up a sensoryprofile: descriptive tests
The panel
What is required of the panel?
To understand the common definition of the terms
To recognise the sensations in the product
To ensure repeatability, reproducibility and discrimination
To be sensitive48
III. Drawing up a sensoryprofile: descriptive tests
The panel
General recommendations Be in good health, report any sickness
Avoid body odours and cosmetics
Do not smoke, eat/drink or use strong products within at least one hour before the tests
Be punctual under all circumstances
Remain silent
Read the questionnaires attentively
Rinse out the mouth as often as possible 49
III. Drawing up a sensoryprofile: descriptive tests
The panel
Recruitment How many?
Twice as many as required for the panel(example for 10 subjects routinely, 20 selected, hence 40 recruited)
How? Selection criteria:
• Interest and motivation• Behaviour with regard to food products• Knowledge and abilities (concentration, etc.)• Health• Communication skills• Availability• Behaviour: persistent, punctual, reliable and honest50
III. Drawing up a sensoryprofile: descriptive tests
- Pre-selection: questionnaire (availability, health, etc.)
- Selection:. Laboratory presentation, sensory analysis. Testing (taste, odour, discriminative)
- General training / Performance check. Initiation of new judges. Annual training
- Specific grid training prior to testing / Performance check
The panel
Selection / Training
52
III. Drawing up a sensoryprofile: descriptive tests
The panel Performance checkSt
icky
Flo
ury
Firm
Sou
r
Bit
ter
Swe
et
Ast
rin
gen
t
Mo
ist
Pe
rsis
ten
ce in
th
e m
ou
th
Po
tato
Art
ich
oke
Nu
ts
Ove
rall
qu
alit
y
55
III. Drawin up a sensoryprofile: descriptive tests
The panel
In the long-term …
…. it is important to accommodate and motivate the subjects
After the studies, explain how the results are to be used
Gifts or compensation
Regularly provide guidance on theirperformance
Use codes to designate the subjects, and refrain from commenting on their results as a group
56
Essential points of protocol
III. Drawing up a sensoryprofile: descriptive tests
Watch out for representativeness and preservation of the sample
Presentation method: as realistic as possible, practical
Sample homogeneity: T°, quantity, contents
Choose the number of repetitions
Make the samples anonymous
Distribution in random order 58
III. Drawing up a sensoryprofile: descriptive tests
Protocol essential points
Anonymous tasting, but explanatory feedback after the test (meeting, sheets, etc.)
Product sanitary quality check
Tasters’ consent (form, contract, etc.)
62
III. Drawing up a sensoryprofile: descriptive tests
Protocol essential points
Other than for routine tests, the protocol developmentrequires knowledge of sensory analysis but also theproduct
Must be based on standards for sensory analysis, for the product studied
We can use books or articles published on the subject
We can also work with people with a very good knowledge of the product (selector, preparers, etc.)
63
III. Drawing up a sensoryprofile: descriptive tests
Drawing up the protocol
Choice of scoring scale It must above all be suitable for the subjects and the
objective
In general, contains only positive numbers or zero
Scoring scales / intervals (interval equality criterion)- structured (for example 1 to 9 or 0 to 5)- unstructured (trait)
64
III. Drawing up a sensoryprofile: descriptive tests
Drawing up the protocol
Choice of descriptors Existing vocabulary proposed
check relevance
Created through individual and collective work by tasters
Vocabulary generated
- At least 6 subjects- Range of products to cover all the possible qualitative
differences65
III. Drawing up a sensoryprofile: descriptive tests
Step 1: generate a large number of descriptors Step 2: select and reduce
- The descriptors must not be hedonic- The descriptors must make it possible to differentiate the products- Synonymous or overly-similar terms eliminated- We should end up with around 15-20 descriptors
Step 3: choice of references for each descriptor (stable orreproducible)
Step 4: specific training Step 5: repeatability test
Generating vocabulary:
Drawing up the protocol
Choice of descriptors
66
III. Drawing up a sensoryprofile: descriptive tests
Examples of descriptors:
Drawing up the protocol
Choice of descriptors
67
Preparing the questionnaires
III. Drawing up a sensory profile: descriptive tests
Example of tasting sheets
Drawn up from information gathered (customers, panel, etc.)
Organoleptic characterisation: visual, olfactory, gustatory examination, etc., overall quality (scoring on a scale)
The taster can note down comments69
III. Drawing up a sensory profile: descriptive tests
Preparing the questionnaires
Example of tasting
sheets
70
Plan
I. What is sensory analysis: perception and measurement Some definitions Physiology of perception Sensory response
II. The various types of sensory tests Analytical (discriminative, descriptive) Hedonic
III. Drawing up a sensory profile: descriptive tests The working environment: the laboratory The panel Drawing up the protocol Preparing the questionnaires
IV. In practice ... Setting up a panel Recruitment General training Specific product training 71
IV. In practice … Setting up a panel
Recruitment
Men / Women aged 18 to 60, in-houseremuneration??contracted
Minimum: 8 people12 – 15 trained people +++
check state of health, availability, motivationquestionnaires
73
IV. In practice … Setting up a panel
General training
Basic taste and impressions recognition test
Salty / sweet ranking test
Sour / bitter / astringent perception threshold
Triangular test on a specific product common to the various countries: pure and diluted orange juice???
Odour recognition test: 4 odours (brown bottle with citrus zest / coffee grounds / flowers / fruit / spice / grass???)
74
IV. In practice … Setting up a panel
General training
If a judge makes 2 or 3 errors out of 5 tastes / impressions during the ranking and perception tests, they must retake the recognition test 1
If in test 1 they make 2 errors out of 6 responses (tastes / impressions / water), they are permanently removed from the panel
Each judge approved to remain on the tasting panel will take this general training once a year
Selection
75
Specific product training
IV. In practice … Setting up a panel
0 to 10 scale
Session 1: Vocabulary generated by consensus (> 70% mentions after discussions) on 3 contrasting products
Session 2: Tasting sheet with the definitions, evaluation protocol, scaled score (boundaries and intermediates) on the 3 contrasting products above
Session 3: Work on scale with 3 - 4 reference products. Initial score / correction / discussions
Session 4: Same test on the 3 - 4 reference products but individual scoring
Session 5: Same test followed by data processing (judge mean, repeatability, homogeneity of panel, etc.) 76
IV. In practice … Setting up a panel
Specific product training
Approved / re-adjusted / re-trained
This specific training must be conducted before the start of every test / campaign
Testing
Number of repetitions to be defined
77
Useful references
• Normes ISO :AFNOR (2007). Analyse sensorielle 7ème édition. La Plaine
Saint Denis, AFNOR.
• Livre généralisteSSHA and F. Depledt (2009). Evaluation sensorielle
Manuel méthodologique 3ème édition. Paris, Lavoisier
• Guide des bonnes pratiquesACTIA (1999). Evaluation sensorielle Guide de bonnes
pratiques, ACTIA (Association de coordination technique pour l'industrie agro-alimentaire).
78