How reliable are the consumers?Comparison of sensory profiles

from consumers and expertsWORCH Thierry(1)

LÊ Sébastien(2)

PUNTER Pieter(1)

(1) OPP Product Research(2) AgroCampus Ouest

Project 8013July 2008

Senior project manager Pieter PunterProject manager Thierry Worch

mailto: thierry@opp.nl

8013 3

introduction

• in the sensory theory:• experts panels are used for the products’ description

• consumers should only be used for the hedonic task• they lack two essentials qualities for profiling (consensus and reproducibility) • there are strong halo effects (Earthy, MacFie & Hedderley, 1997)

• in the sensory practice:• consumers are sometimes used for both tasks• it has been proven that consumers’ description show the required qualities (consensus and reproducibility) (Husson, Le Dien, Pagès, 2001)

8013 4

problematic

How reliable are the consumers?

8013 5

presentation of the studies

• products:• twelve luxurious women perfumes

(Gazano, Ballay, Eladan & Sieffermann, 2005)

Angel (Eau de Parfum)

L’Instant(Eau de Parfum)

Cinéma (Eau de Parfum)

J’Adore(Eau de Toilette)

Pleasures (Eau de Parfum)

J’Adore(Eau de Parfum)

Aromatics Elixir(Eau de Parfum)

Pure Poison(Eau de Parfum)

Lolita Lempicka(Eau de Parfum)

Shalimar(Eau de Toilette)

Chanel N°5(Eau de Parfum)

Coco Mademoiselle(Eau de Parfum)

8013 6

presentation of the studies

• expert panel (Agrocampus Rennes)

• twelve persons (11 students and 1 teacher) from the Chantal Le Cozic school (esthetics and cosmetic school)

• focus group per group of six, with two animators• generation of a list of twelve attributes

• “Vanille”, “Notes Florales”, “Agrume”, “Boisé”, “Vert”, “Epicé”, “Capiteux”, “Fruité”, “Fraîcheur Marine”, “Gourmand”, “Oriental”, “Enveloppant”

• training session for the most difficult ones

• the twelve products were tested two times in two one-hour sessions

8013 7

presentation of the studies

• consumer panel (OP&P Product Research, Utrecht)

• 103 naïve Dutch consumers living in the Utrecht area

• the same twelve perfumes were rated on 21 attributes• “odour intensity”, “freshness”, “jasmine”, “rose”, “camomile”, “fresh lemon”, “vanilla”, “mandarin/orange”, “anis”, “sweet fruit/melon”, “honey”, “caramel”, “spicy”, “woody”, “leather”, “nutty/almond”, “musk”, “animal”, “earthy”, “incense”, “green”

• two products (Shalimar and Pure Poison) were duplicated

• the fourteen (12+2) products were tasted in two one-hour sessions (seven products in each session, presentation order was balanced)

8013 8

presentation route map

• the consumer and expert data are compared in three different ways

1.Univariate analysis• analyses of variance • correlations

2.Multivariate comparison• construction of the two products’ spaces (PCA)• comparison of the products’ spaces through GPA and MFA

3.Confidence ellipses • graphical confidence intervals around the products averaged over the two panels• graphical confidence intervals around the products defined by the different panels

8013 9

Performance of the two panels(univariate analysis)

8013 10

performance of the panels

• usually, the expert panels should have many qualities:

• discrimination: panelists should be able to detect and describe the differences existing between the products

• reproducibility: panelists should describe the products in the same way, when they are repeated

• agreement: panelists should give the same description of the products as the rest of the panel

• it can be measured with the correlations (usually, one panelist is compared to the mean over the rest of the panel)

8013 11

expert panel

• panel performance

• discriminate on 11 out of 12 attributes (“Agrume”, pvalue=0.08)• reproducible for 11 out of 12 attributes (“Notes Florales”)

• panellist performance (discrimination, reproducibility)

• panellists 1, 3 and 12 are very good • panellists 8, 9 and 10 are not good in discrimination (discriminate the products on less than 6 out of 12 attributes)• panellist 9 is also not good in reproducibility (reproducible ononly 3 out of 12 attributes. “Notes Florales”, “Agrume” and “Enveloppant”)

8013 12

expert panel (correlations)

• distribution of the correlations (correlation between expert i and the mean over the (n-1) others)

0

1

2

3

4

5

6

-1,0

0

-0,9

0

-0,8

0

-0,7

0

-0,6

0

-0,5

0

-0,4

0

-0,3

0

-0,2

0

-0,1

0

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

0,80

0,90

1,00

8013 13

consumer panel

• discrimination (on the twelve original products)

• the consumers discriminate the products on all attributes except“camomile” (pvalue = 0.62)

• NB: the consumers discriminate on “Citrus” (pvalue < 0.001)

• reproducibility (on the two duplicated products only)

• consumers are reproducible on all attributes except one (“woody”)

8013 14

consumer panel (reproducibility)

Pure Poison

Pure Poison 2

intensityfreshness

jasmin

rose

camomille

fresh_lemon

vanilla

citrus

anis

sweet_fruithoneycaramel

spicy

woody

leather

nutty

musk

animal

earthy

incense

green

10

20

30

40

50

60

70

8013 15

consumer panel (reproducibility)intensity

freshness

jasmin

rose

camomille

fresh_lemon

vanilla

citrus

anis

sweet_fruithoneycaramel

spicy

woody

leather

nutty

musk

animal

earthy

incense

green

10

20

30

40

50

60

70Shalimar

Shalimar 2

8013 16

consumer panel (correlations)

• distribution of the correlations (correlation between a consumer i and the mean over the (n-1) others)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

-1,00-0,90

-0,80-0,70

-0,60-0,50

-0,40-0,30

-0,20-0,10

0,000,10

0,200,30

0,400,50

0,600,70

0,800,90

1,00

8013 17

conclusions on the panel performance

• expert panel• discriminates between the products• are reproducible• high correlations

• consumer panel• discriminates between the products• shows reproducibility’s qualities• lower but still positive correlations (consumers are untrained)

Both panels show the same qualities

8013 18

Products’ spaces(multivariate analysis)

8013 19

methodology

• products’ spaces• the products profiles (averaged over the panellists or consumers) are computed.• Principal Components Analysis is then run on these product x attribute matrices

• comparison of the two products’ spaces (expert and consumer) is a “multi-table problem”

• comparison through the Procrustean analysis• comparison through Multiple Factor Analysis (MFA)• comparison through the confidence ellipses technique

8013 20

expert panelg p

-4 -3 -2 -1 0 1 2 3 4

Dimension 1 (64.22 %)

-4,5

-4,0

-3,5

-3,0

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

Dim

ensi

on 2

(21.

87 %

)

Angel

AromaticsElixir

Chaneln5

Cinema

CocoMelle

JAdore_EP

JAdore_ET

LInstant

LolitaLempicka

Pleasures

PurePoison

Shalimar

-1 0 1

Dimension 1 (64.22 %)

-1

0

1

Dim

ensi

on 2

(21.

87 %

)

Epicé

Capiteux

Fruité

Vert

Vanille

Notes.florales

Boisé

Agrume

Fraicheur.marine

Gourmand

Oriental

Enveloppant

8013 21

expert panel (conclusions)

• first dimension (64% of the total inertia) shows two clusters:• Aromatics Elixir, Shalimar, Angel, Chanel n5 and Lolita Lempicka(characterized by Epice, Oriental, Capiteux, Enveloppant)

• versus• Pleasures, J’Adore (EP and ET) (characterized by Fraicheur Marine, Agrume, Notes Florales, Vert, Fruité)

• second dimension (22% of the total inertia) discriminates between• Aromatics Elixir, Shalimar (characterized by Boisé)

• versus• Lolita Lempicka (characterized by Gourmand, Vanille)

8013 22

consumer panel

-5 -2.5 0 2.5 5 7.5

Dimension 1 (68.29 %)

-7,0

-6,5

-6,0

-5,5

-5,0

-4,5

-4,0

-3,5

-3,0

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

5,0

5,5

6,0

Dim

ensi

on 2

(17.

97 %

)

Angel

AromaticsElixir

Chaneln5

Cinema

CocoMelle

JAdore_EP

JAdore_ET

LInstant

LolitaLempicka

Pleasures PurePoison

Shalimar

g

-1 0 1

Dimension 1 (68.29 %)

-1

0

1

Dim

ensi

on 2

(17.

97 %

)

intensity

freshness

jasminrose

camomille

fresh_lemon

vanilla

citrus

anis

sweet_fruit

honey

caramel

spicy

woodyleather

nutty

muskanimal

earthy

incense

green

8013 23

consumer panel (conclusions)

• first dimension (68% of the total inertia) shows two clusters• Angel, Shalimar, Aromatics Elixir (characterized by nutty, animal, musk, incense, leather, woody earthy, spicy)

• versus• J’Adore (EP and ET), Pleasures (characterized by citrus, sweet fruit, freshness, green, jasmin, rose, fresh lemon)

• second dimension (18% of the total inertia) discriminates between • Lolita Lempicka (characterized by vanilla, honey, camomile, caramel)

• versus• Aromatics Elixir, Shalimar (characterized by intense, spicy)

8013 24

Multivariate comparison of the two panels (GPA and MFA)

8013 25

expert vs consumer: Procrustes analysis

GPA consensus space

(coefficient of similarity: 0.93)

-0.2 0.0 0.2 0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

Dim 1

Dim

2

Angel

AromaticsElixir

Chaneln5

Cinema

CocoMelleJAdore_EPJAdore_ET

LInstant

LolitaLempicka

PleasuresPurePoison

Shalimar

8013 26

expert vs consumer: Multiple Factor Analysis

-2 -1 0 1 2 3

-2-1

01

2

Dim 1 (64.06 %)

Dim

2 (1

9.35

%)

I di id l f t

Angel

AromaticsElixir

Chaneln5

Cinema

CocoMelleJAdore_EPJAdore_ET

LInstant

LolitaLempicka

PleasuresPurePoison

Shalimar

expertsconsommateurs

MFA partial points’representation

(RV coefficient: 0.87)

8013 27

expert vs consumer: Multiple Factor Analysisg p

-1 0 1

Dimension 1 (64.05 %)

-1

0

1

Dim

ensi

on 2

(19.

35 %

)

Epicé

Capiteux

Fruité

Vert

Vanille

Notes.florales

Boisé

Agrume

Fraicheur.marine

Gourmand

Oriental

Enveloppant

intensity

freshness

jasminrose

camomille

fresh_lemon

vanilla

citrus

anis

sweet_fruit

honey

caramel

spicy

woodyleather

nutty

muskanimal

earthyincense

green

MFA variables’representation

(RV coefficient: 0.87)

expert

consumer

8013 28

Comparison through theconfidence ellipses technique

(Husson, Lê & Pagès, 2005)(Lê, Pagès & Husson, 2008)

8013 29

confidence ellipses

methodology

1.Compute the product profiles (averaged by product over the judges)2.Create the products’ space3.Re-sample by bootstraping new panels4.For each new panel, compute new products’ profiles5.Project as illustrative the products on the original product space6.Steps 3 to 5 are repeated many times (i.e. 500 times)7.Confidence ellipses around the products containing 95% of the data are constructed

principle• if ellipses are superimposed, the products are not significantly different• the size of the ellipses is related to the variability existing around the products

8013 30

confidence ellipses

-3 -2 -1 0 1 2 3 4

-10

12

Dim 1 (64.02%)

Dim

2 (1

9.39

%)

Angel

AromaticsElixir

Chaneln5

Cinema

CocoMelleJAdore_EPJAdore_ET

LInstant

LolitaLempicka

PleasuresPurePoison

Shalimar

Confidence ellipses around the products

8013 31

confidence ellipses

• mean points

• some products are not significantly different • J’Adore ET, J’Adore EP and Pleasures• Cinema and L’Instant

• some products are clearly significantly different• Angel and J’Adore (ET or EP)• Chanel n°5 and Shalimar

8013 32

confidence ellipses

• as we have two different panels, we can apply this methodology to both

• creation of confidence ellipses around each product seen by each panel (24 ellipses are created here)

• comparison of a given product through the two panels (same colour)

• comparison of the different products within a panel (same type of line)

8013 33

confidence ellipses

Confidence ellipses for the partial points

-4 -2 0 2 4

-2-1

01

2

Dim 1 (64.02%)

Dim

2 (1

9.39

%) Angel

AromaticsElixir

Chaneln5

Cinema

CocoMelleJAdore_EPJAdore_ET

LInstant

LolitaLempicka

PleasuresPurePoison

Shalimar

cons.expert

8013 34

confidence ellipses

• partial points

• within a product, the ellipses related to the two panels are always superimposed (no differences between the panels)

• the sizes of the ellipses are equal• the higher amount of consumers compensate the higher variability due to the lack of training for consumers

8013 35

conclusions

• although consumers don’t have the habit to describe perfumes (difficult task), they give the same information as the expert panel (and it’s identical to the standard description of the perfumes)

• they also have the same qualities (discrimination and reproducibility)

• a difference between consumers and experts panel exists in the variability of the results (more variability for consumers), but this is compensated by the larger size of the panel (here 103 vs 12)

• with consumers, not only intensity, but also ideal and hedonic questions can be asked in the same time

8013 36

references

• Earthy P., MacFie H & Hedderlay D. (1997). Effect of question order on sensory perception and preference in central locations. Journal of Sensory Studies, vol.12, p215-237

• Gazano G., Ballay S., Eladan N. & Sieffermann J.M. (2005). Flash Profile and flagrance research: using the words of the naïve consumers to better grasp the perfume’s universe. In: ESOMAR Fragrance Research Conference, 15-17 May 2005, New York, NY.

• Husson F., Le Dien S. & Pagès J. (2001). Which value can be granted to sensory profiles give by consumers? Methodology and results. Food Quality and Preference, vol.16, p291-296

• Husson F., Lê S.& Pagès J. (2005). Confidence ellipses for the sensory profile obtained by principal component analysis. Food Quality and Preference, vol.16, p245-250

• Lê S., Pagès J. & Husson F. (2008). Methodology for the comparison of sensory profiles provided by several panels: Application to a cross cultural study. Food Quality and Preference, vol.19, p179-184

8013 37

thank you

• special thanks to• Melanie COUSIN• Maëlle PENVEN• Mathilde PHILIPPE• Marie TOULARHOAT

students from AgroCampus-Rennes, who took care of the whole expert panel data.

Thank you for your attention!