Samenvatting Class notes - Principles of Sensory Science

- Principles of Sensory Science
- Dr. Sanne Boesveldt
- 2020 - 2021
- Wageningen University (Wageningen University, Wageningen)
- Voeding en Gezondheid
208 Flashcards en notities
1 Studenten
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Samenvatting - Class notes - Principles of Sensory Science

  • 1601589600 Introduction to Sensory Science

  • Without smell your flavour perception is limited
  • What is the definition of sensory evaluation?
    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.
  • What are the three basic test methods?

    • Are products different 
    • Analytic 
    • Screened or trained (n=10-12)

    • How do products differ?
    • Analytic 
    • Screened or trained (n=20-40)

    • How well are products liked?
    • Hedonic
    • Screened for product use, untrained (n=75-150)
  • Het verschil tussen Analytical sensory tests en Hedonic sensory tests
    Analytical sensory tests
    • Intensity, amount, duration 
    • strong control, high internal validity 
    • reliability, sensitivity 
    • few subjects, many samples

    Hedonic sensory tests
    • predictive of real life
    • as a whole, integrated
    • weaker control, high external validity 
    • many subjects, few samples
  • For what do we collect sensory data
    Food industry 

    research and public health 
  • Wat is het verschil tussen psychophysics en psychohedonics?
    Psychophysics is the relation between the physical chemical properties of a food and the perception of it by the consumer or panellists
    • for example how sweet you perceive the taste of this banana when you take a bite is related to its sugar concentration 

    Psychohedonics focuses on the relation between physical chemical properties, so concentration and the pleasantness or liking of a food
  • Hoe ziet Psychophysics er in een grafiek uit ?
    Zie de afbeelding

    In een stijgende lijn
  • Hoe ziet Psychohedonics er in een grafiek uit?
    Zie de afbeelding

    Een Wundt curve (inverted U-curve)
  • What are the individual differences in perception? And what do they affect?
    Age, gender, satiation etc. 

    They can affect 
    • Thresholds
    • suprathreshold sensitivity 
    • identification ability 
    • liking/preferences 
  • Wat heeft invloed op de replication & reliability 
    (Wat zorgt ervoor dat ze stabiel blijven)
    Order effect

    Frame of reference
  • 1601848800 Descriptive analysis

  • What is the definition of descriptive sensory analysis?
    A method aiming to provide a quantitative measure of the sensory properties of a set of products
  • What are the applications of descriptive analysis?
    Food industry 
    • Product reformulations 
    • New product development 
    • Quality control 
      • acceptability to target
      • calibration of instruments 
    • Brand mapping 
    • Consumer preference mapping 

    • Understanding relationships:
      • product/process/production properties 
      • perceptible properties 
  • The Descriptive analysis techniques kunnen worden onderverdeeld in twee categorie├źn. Welke?
    Dynamic methods
    • are developed to get a sensory description of a food product that develops overtime (for instance during consumption or chewing)

    Static methods 
    •  only measure snapshots of the sensory profiles at a certain time point 
  • What are the three differences between the methods for descriptive analysis techniques?

    Methods are Dynamic and Static 
    • Generation of sensory descriptors (attributes)
    • Degree of subject training
    • Use of reference materials and scaling and anchors are used
  • What is the first developed descriptive method?
    Flavor profile method
  • What is the history of flavour profile method? Why was it made?
    There was a need for a more precise mean of measuring the flavour of a food.

    • Trademark of Arthur D. Little company
    • Late 1940s / early 1950s
    • Loren Sjostrom, Stanley Cairncross and Jean Caul 
  • How does the flavour profile method work?
    • It uses a consensus technique
      • trained subjects evaluate food product while discussing and defining the flavour attributes together
    • 4-6 judges; 2-3 weeks training
    • Reference materials for discussing and defining flavours
    • It only focussen on the flavour attributes of a food product

    The estimate intensity of flavour attributes is rated 
    • 0 = not present 
    • )( = threshols/just noticeable
    • 1 = slight
    • 2 = moderate
    • 3 = strong
    • options to expand: + - 1/2 etc

    As well as the estimated intensity of overall amplitude (overall balance and blending) of the product
    • )( = very low
    • 1 = low
    • 2 = medium 
    • 3 = high
  • What are the limitations of the flavour profile method?

    • It can be seen as a qualitative descriptive method (consensus)
      • No statistical analysis possible (only descriptions of the flavours can be made)
    • This profile method is limited to flavour impressions only (so not for texture, appearance)
  • Consensus decision making is a creative and dynamic way of reaching agreement between all members of a group. 
    Instead of simply voting for an item and having the majority of the group getting their way, a group using consensus is committed to finding solutions that everyone actively supports, or at least can live with.
  • Na flavour profile method, is Quantitative descriptive analysis ontwikkeld
  • What is the History of Quantitative descriptive analysis?
    • All modalities! (i.p.v. Only flavour)
    • Individual profiles! (i.p.v. One product profile)
    • developed in 1970s
    • Stone and Sidel
    • Trademark
  • What is the principle of quantitative descriptive analysis?
    • Data from individual panelists (n=10-12)
    • Sensory booths
    • Attribute generation and use > consensus approach
      • all modalities
      • panel leader passive facilitator
    • Reference standards used occasionally
    • VAS-scale is used for measuring intensity 
  • What are the limitations of the QDA method?
    • Time to invest in panel training and monitoring 
    • No absolute intensity scores (maar wel: relative differences between product)
      • dus er kunnen geen nummers gebruikt worden (e.g. De groene appel scoort 80 op zuur) nee, maar wel dat de groene appel zuurder is dan de gele en rode appel.
  • Texture profile method is net na de flavour profile method ontwikkeld.
  • What is the history of texture profile method?
    • Texture! (naar koekjes kijkende is smaak niet genoeg)
    • Need for a standardised method for evaluation of cereals, biscuits etc. 
    • 1960 at General Foods ( > Kraft Foods > now Kraft Heinz)
  • Wat is the principle of the texture profile method?
    "The sensory analysis of the texture complex of a food in terms of its mechanical, geometrical, fat and moisture characteristics, the degree of each present and the order in which they appear from first bite through complete mastication"

    • Temporal process need to be taken into account (the bite is different from the chewing)
    • Fixed sensory vocabulary (attributes + definition) related to physical standards
    • intensity scales labelled with references 

    Zie afbeelding voor voorbeeld
  • Texture profile vocabulary can be slit in 3 categories. And these 3 categories can than be explained by 3 other categories.
    Geometrical, Mechanical, Other characteristics

    Deze 3 kunnen weer beter worden uitgelegd door 
    • Primary parameters
    • Secondary parameters
    • Main adjectives
  • What are the limitations of texture profile method?
    • High degree of training 
      • Vocabulary can be used as inspiration!

    • The exact attributes with description should be used. (use of strict vocabulary)
      • Er mag geen verwarring ontstaan
  • Sensory Spectrum is developed early and is based on the texture profile
  • What is the history of sensory spectrum
    • 1970s Gail Civille (General Foods)
    • Generalization of Texture profile method
    • Evaluation on all modalities (not only on texture)
  • The principles of sensory spectrum are...
    (Similar to texture profile)
    • Standardized attributes and response scales 
      • attributes are fixed and choose before hand 
    • High involvement of panel leader 
      • intensive training of panel is necessary 

    • comparison over time 
    • comparable between cultures?
  • The results of different panels trained with the spectrum method are

    regardless of cultural/geographical differences!

    (Similar taste evaluations)
  • What are the limitations of sensory spectrum
    • High degree of panelist training 
    • more time-consuming than consensus training using own vocabulary
  • Rapid sensory profilling methods are new and are at the bodem of the descriptive analysis overview
  • Rapid sensory profilling methods bestaat uit vele methodes. De twee belangrijkste/veel voorkomende zijn
    Verbal-based methods and similarity-based methods
  • What are the verbal-based methods
    • Flash Profile 
    • Check All That Apply (CATA)

    1. Allows panelists to use their own set of attributes
    2. No training on attributes or scaling necessary 
  • Flash profile =
    • Experienced/expert subjects (n=5-10)
    • Ranking on individual set of attributes (can be a lot!)
    • ordinal data
    • Advantage: repetition
    • Disadvange: large number of attributes
  • Check All That Apply (CATA) =
    • Consumer/expert panel
    • Prepared list of attributes
    • Tick attributes that apply, repeat per product
    • Frequency data (0 and 1)
  • What are the Similarity-based methods
    • Sorting 
    • Napping 
      • Ultra Flash Profile 
      • Partial Napping 

    • Based on overall differences between products
  • Sorting method =
    • Group products together with similar characteristics
      • welke horen er bij sour welke bij fruity (groeperen)
    • Option: add terms to groups (labelled sorting)
    • Data: similarity matrix (0 and 1)
  • Napping method =
    • the results are not accurate!
    • Quick screening of many samples
    • Place products on a 'napkin' according to differences and similarities
    • Data: x, y coordinates for each product
  • Napping kun je onderverdelen in 2 sub groepen
    Ultra Flash Profile:
    • Add terms to product map

    Partial Napping:
    • Focus on one modality (at a time)
      • dus eerst alles voor smell daarna voor taste etc.
    • Dit kost meer tijd dus ook meer tijd nodig voor de data analyse
  • There is a concern on lack of training when looking at napping. What happens if there is a trained panel?
    • Better product discrimination after more training
    • Training on product level most effective
  • What is the comparison of conventional descriptive profile and some rapid methods?
    • More training leads to more accurate results
    • Simple adjustments can make a difference
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Laatst toegevoegde flashcards

Adaptation level theory =
People adapt to a level of sensory stimulation
What are the three differences between the methods for descriptive analysis techniques?Methods are Dynamic and Static 
  • Generation of sensory descriptors (attributes)
  • Degree of subject training
  • Use of reference materials and scaling and anchors are used
Liking While Dominant (LWD) scoreProduct average of liking weighed by DR attribute
Fresh herbs, salty and pungent are positive drivers of liking, whereas cooked herbs and pepper are negative ones. Garlic, cream and sour are neutral.
Liking but dominant score
Step 1: superimposing dominance and liking periods 

Er worden twee tijdlijnen verzameld: die van de attributes en die van de liking. 

Step 2: adding liking scores to dominance periods 
  • linking increased from 4 to 5 during the cream dominance period 
  • Fresh herbs had 2 periods of dominance during which liking was respectively 4 and 5 
  • pungent had a single period of dominance with a constant liking os 4 
  • cooked herbs characterised the last period during which liking is dramatically decreasing from 5 to 2
Temporality of liking (Temporal drivers of liking)
"step 1:" Classical liking: How much do you like it (9 point hedonic scale)

"step2:" Temporal Last Liking score: Gedurende het proeven de linking aangeven. 

"step3:" Liking score after 1 min: pas na 1 minuut na doorslikken wordt er gevraagd hoe lekker ze het vinden 

De liking is in de 3 verschillenden sessies verschillend. 

Temporal liking is more discriminative than classic liking and product ranking is not identical in the two methods.
Comparison between TI, TDS, TCATA
  • Analytic; intensity profile of a single sensory attribute over time
  • Time intensive (expense); single run needed per attribute
  • Quantitative; different parameters curve
  • Trained panellists; extensive training required

  • Intuitive; monitor changing dominant sensory attribute from a set of 10-12 attributes over time
  • Faster (less expensive); single run allows temporal responses for 10-12 attributes at one time
  • Qualitative; dominance duration, no intensity
  • Naive/consumer panellists; no extensive training required

  • Analytic/intuitive; monitor applicability (yes/no) of one or more sensory attributes from a set of 10-12 attributes over time
  • Faster (less expensive); singel run allows temporal responses for 10-12 attributes at one time
  • Qualitative; citation frequency, no intensity
  • ? Both trained + naive panellists, but complex to perform
What is the difference between TDS and TCATA
  • Dominance
  • the sensation that catches most of the attention at a given time
    • at first the food is crunchy but then it is sweet and then sticky

  • applicability
  • the sensation that are applicable at a given time
    • at first the food is crunchy & sour but then it is sweet &creamy and then sticky
What is the interpretation of the data when performing a TCATA
TCATA is about citation frequencies, citation proportions

The proportion of panellists that thinks that a certain attribute is applicable to the product at certain time point.

Where TDS is about dominance over time 
Temporal Check-All-That-Apply (TCATA)
Naast en aanklikken van alle attributen die van toepassing zijn (CATA), wordt er ook aan de deelnemer gevraagd wanneer deze attributen van toepassing zijn (TCATA).

er wordt gevraagd naar applicable en niet naar dominant 
Hoe ziet een band-plot eruit?
Zie de afbeelding

allowing to display every product on a single plot!