sensory evaluation 1.ppt

Yes

1. SENSORY EVALUATION
FSN 501 (1+1) 1

2. SENSORY EVALUATION
Whenthequalityofafoodproductisassessedbymeansofhumansensory
organs,theevaluationissaidtobesensoryorsubjectiveororganoleptic.Every
timefoodiseatenajudgementismade.
Definition:
USAdefinedSensoryEvaluationasascientific
disciplineusedtoevokemeasures,analyseandinterpret
reactionstothosecharacteristicoffoodandmaterialsas
theyareperceivedbysensesofsight,smell,taste,
touchandhearing.
FSN 501 (1+1) 2

3. WHY SENSORY EVALUATION USED
Itreducesuncertaintyandrisksindecisionmaking.
Itensuresacostefficientdeliveryofnewproductswith
highconsumeracceptability.
Humanobservesaregoodmeasuringinstruments.
FSN 501 (1+1) 3

4. QUALITY EVALUATION
Qualityistheultimatecriterionofthedesirabilityofanyfood
products.Foodqualitycanbeevaluatedbysubjectiveandobjective
methods.
subjectivemethods objectivemethods
Appearance 1Physicalmethods
Texturometer
Taste Colorimeter
Texture Tenderometer
Colour Succulometer
Viscometer
Consistometer
Electricnose
2Chemicalmethod
FSN 501 (1+1) 4

5. SUBJECTIVE METHOD
Thesemethodsofqualityevaluationarebasedon
theopinionoftheinvestigators.Thesearetheindividual
experienceandpreference.Theyaresubjectivebecausethe
individualisrequiredtogivehisopinion.Thesensoryorgans
areappearance,taste,textureflavour.
FSN 501 (1+1) 5

6. APPEARANCE
Surfacecharacteristicoffoodproductscontributetotheappearance.
Interiorappearancecanalsobeevaluated.Lumpsinapuddingorgravy
arenotdesirablecanbejudgedbytheeye.
FSN 501 (1+1) 6

7. TASTE
Tastesensationwhichthetastebudsregisterare
categorisedassweet,salt,sourorbitter.
Tastebudsnearthetipofthetonguearemoresensitive
tosweetandsalt.
Thoseonthesidessourandthoseneartheback
tobitter.
FSN 501 (1+1) 7

8. TEXTURE
Textureinicecreamdependsuponthesizeofthe
crystals.
Coarsetexturecrystallineproductsaresaidtobegrainy.
Thebrittlenessoffoodisanotheraspectoftexture.
FSN 501 (1+1) 8

9. COLOUR
Ripenessoffruitslikebanana,mango,guava,papayaand
plumcanbeassedbythecolour.
Colourisusedasanindextothequalityofanumberof
foods.
Thestrengthofcoffeeandteaisjudgedinpartbythe
colourofthebeverages.
FSN 501 (1+1) 9

10. OBJECTIVE METHODS
Methodsofevaluatingfoodqualitythatdependsonsome
measureotherthanthehumansensesareoftencalledobjectivemethods
ofevaluation.
1.PHYSICALMETHODSOFMEASUREMENTS
Thismethodsusesthedifferentequipmentsforassessing
thephysicalattributesofthefoodproducts.
FSN 501 (1+1) 10

11. COLORIMETER
Helpstomeasuretheintensityofthecolorofthefood
product.
Usedinjuicestomeasuretheclarity.
FSN 501 (1+1) 11

12. TEXTUROMETER
Measures the texture of the
food products
Measures smoothness , stickiness,
crunchiness, softness, juiciness,
handful, mouthfeel etc.
It measures the amount of
food tensile strength.
FSN 501 (1+1) 12

13. TENDEROMETER
Thisappliescompression,shear
tomeasurethetenderness.
Itisusedtomeasurethetenderness
ofanimalproductslikemeat.
Varioussmallteethlikestructure
arepresentwhichispressedinto
thedistanceitmoveinsidetellsabout
thetenderness.
FSN 501 (1+1) 13

14. SUCCULOMETER
Compression to squeeze
juice out of food as a
measure of succulence.
FSN 501 (1+1) 14

15. VISCOMETER
Itmeasuresthetimerequired
forthefoodproducttorun
throughasmallholeofknown
diameter.
Thetermviscosityisusedfor
theproductsuchasketchup,
honeyorsugarsyrupetc.
FSN 501 (1+1) 15

16. CONSISTOMETER
Thisdevicealsomeasuresthe
timerequiredforthefoodtomove
throughtheholeofknowndiameter.
Consistometerisusedforproducts
suchasporridge,maltetc.
Measuresthethicknessorthe
thinnessoftheproduct.
FSN 501 (1+1) 16

17. ELECTRIC NOSE
Itusedtoassessthetypeof
aromapresentinthefood.
Chancesoferrorsisvery
negligibleasthehuman
subjectsarenotpresent.
FSN 501 (1+1) 17

18. 2. CHEMICAL METHODS OF MEASUREMENTS
Chemicalsareestimatedinfoodspoilinglikeperoxidein
fats.
Adulterationinfoodse.g,,presenceofstarchinmilk,
metanilyellowinturmericpowderandlossofnutrients
duringcookingcanbeestimated.
FSN 501 (1+1) 18

19. SUBJECTIVE METHOD OBJECTIVEMETHOD
Uses individual Uses equipment
Involves humans sensory organs Uses physical, chemical techniques
Results may be variable Results are repeatable
Determines human sensitivity Need to find technic applicable for food
Determines consumers acceptance Cannotdetermine consumer acceptance
Time consuming and expensive Essential for routine quality control
Essential for fooddevelopment
FSN 501 (1+1) 19

20. EVALUATION CARD
Thequestionnaireorscorecardshouldbepreparedcarefullyforeach
test.
Thecardshouldbeclearlytypedorprinted.
Itshouldbesimpleanduseunambiguoustermsanddirectionsinthe
desiredsequenceofactionasaguidetotheevaluation.
Ascorecardmaybeassimpleasindicatingwhichsampleisdifferent
asdonewhenduotrioortriangletestingisthemodebeingused.
Nosinglescorecardfitsallexperiment.Instead,thescorecard
needstobedevelopedforthespecificexperiment.
Allscorecardsshouldcontainthedateandnameofthejudge.
FSN 501 (1+1) 20

21. DIFFERENT TYPES OF TESTS
Different sensory tests are employed for food
evaluation. The tests are grouped into four types.
1.Difference test
2.Rating test
3.Sensitivity test
4.Descriptive test
FSN 501 (1+1) 21

22. DIFFERENCE TEST
A 1. Paired comparison test
Thepanelmembersreceiveseveralpairsofsamples.
Thesemaybedifferentorthesamesamplesineachpair.
Samplesarealwaysgivenincodenumber.
Differentsamplesaregivenineachpairwhichdifferin
theintensityofonecharacteristice,g..sweetness,
bitternessorrancidity.Ineachpair,thesamplewithmore
orlessintensetastewillhavetobepickedout.
FSN 501 (1+1) 22

23. Samplecard:
Name:
Date:
Product
Youaregivenoneorseveralpairsofsample.Evaluatethetwosamplesinthe
pairfor--------
Isthereanydifferencebetweentwosamplesinthepair?
Codeno.ofpairs Yes No
--------- ---------- -----------
--------- ---------- -----------
--------- ---------- -----------
Signature
FSN 501 (1+1) 23

24. A2 . Duo trio test
 Thistestemploysthreesamples,twoidenticalandonedifferent.
Thepanelisfirstgivenoneofthepairofidenticalsamplesasknown
referencesampleRandthentheothertwosuccessivelyinrandomorder
andaskedtomuchoneofthesewiththefirst.
Apositiveanswerisrequiredevenifitisaguess.Thechanceofthe
samplesofplacingthesamplesinacertainorderisonehalf.
FSN 501 (1+1) 24

25. Sample card:
Name:
Date
Product:
The first sample ‘R’ given is the reference sample.
Taste it carefully.
From the pair of coded sample next given, judge which sample is the same as
‘R’.
Set no. Code no. of pairs Same as R
1 ---------- ----------
2 ---------- ----------
3 ---------- ----------
4 ---------- ----------
Signature
FSN 501 (1+1) 25

26. A3. Triangle test
 Thistestemploysthreesamples,twoidenticalandonedifferent,
presentedsimultaneouslytothepanel.
Thejudgeaskedtodeterminewhichofthethreeistheoddsample.
Apositiveanswerrequiredevenifitisguess.Sinceallsamplesare
unknown,thechanceprobabilityofplacingthesampleinacertain
orderinonethird.
TwosamplesA&BcanbepresentedintwocombinationsAAB&BBA&
forreplicationinsixdifferentarrangementsAAB,ABA,BAA,BAB,ABB&
BBA.
FSN 501 (1+1) 26

27. Samplecard:
Name
Date
Product
Twoofthethreesamplesareidentical
.Determinetheoddsample.
Setno.codeno.ofsamplescodeno.oddofsamplescomment
1 ---------- ---------- ----------
2 ---------- ---------- ----------
Signature
FSN 501 (1+1) 27

28. B. RATING TEST
These test given more quantitative data than difference tests
and can be used for the analysis of more than two samples at the same
time.
B1. Ranking test
Thistestisusedtodeterminehowseveralsamplesdifferonthe
basisofasinglecharacteristic.Acontrolneednotbeidentified.
Panellistsarepresentedallsamplessimultaneouslywithcodenumbers
andareaskedtorankallsamplesaccordingtotheintensityofthe
specifiedcharacteristic.Inconsumeranalysis,thepanellistareaskedto
rankthecodedsamplesaccordingtotheirpreference.
FSN 501 (1+1) 28

29. Samplecard
Name
Date
Product
Pleaserankthesamplesinnumericalorderaccordingtoyourpreferenceor
intensityofaromaortastecharacteristicoftheproduct
Intensity/Preference Samplecode
1 ----------
2 ----------
3 ----------
4 ----------
Comments(Typeofoff-flavour.etc.)
Signature:
FSN 501 (1+1) 29

30. B2.Singlesampletest
Thistestisusefulfortestingfoodsthathaveanafter
tasteorflavourcarryoverwhichprecludestestinga
secondsampleatthesamesession.
Thepanellistisaskedtoindicatethepresenceorabsence
and/orintensityofaparticularqualitycharacteristic.
Withtrainedpanellist,thecompletedanalysesoftwoor
moresamplesevaluatedatdifferenttimescanbe
compared.
FSN 501 (1+1) 30

31. Sample card
Name
Date
Product
Please taste and rank the sample carefully. Can you detect any off flavour in the
product?
Circle one
Yes No
If you detect any off-flavour please describe it below.
Intensity(Circle one) Comments
Trace Off-Flavour is due to
Moderate Off-odour
Strong Off-taste
Residual taste
Other defects
Signature FSN 501 (1+1) 31

32. B3. Two sample difference test
Thistestisavariationofthepairedcomparisontestandmeasuresthe
amountofdifferent.
Eachtasterisservedfourpairsofsamples.Eachpairconsistsofan
identifiedreferenceandcodedtestsamples.Intwopairs,thetest
sampleisaduplicateofthereferencesample.Intheothertwopairs,
thetestsampleisthetestvariables.
Thepanellistisaskedtojudgeeachpairindependentlyastothe
degreeofdifferencebetweenthetestsampleandstandardonascale
of‘0’representingnodifferenceto3representingextremedifference.
Additionalquestionsondirectionsondifferencecanalsobeasked.The
panellistisnottoguessandheispanellistforguessingthroughthe
codedduplicatestandardintwopairs.
FSN 501 (1+1) 32

33. Samplecard
Name
Date
Product
1.Comparethecodedsampletothereferencesampleindependentlyineachofthefour
pairsgiven.Testsamplemayormaynotbedifferentfromthereferencesample.
2.Determinethedegreeanddirectionofdifferenceonthefollowingscale.
Degree Direction
Nodifference 0 Superiortostandard S
Veryslightdifference1 Equaltostandard E
Moderatedifference2 Inferiortostandard I
Largedifference 3
3.Commentonwhatthedifferenceisbasedonodourtasteorboth.
Samplecodeno. Degreeofdifference Direction Comment
---------- ----------- ---------- ------
Signature
FSN 501 (1+1) 33

34. B4. Multiple sample test
Inthistestmorethanonetestvariablecanbeevaluatedper
sessionbutwithreducedreliability.
Eachpanellistisserved3to6samplesdependinguponthe
numberoftestvariables.Onesampleisaknownstandard.
Thepanellistcompareseachcodedsamplewiththeknown
standard.Onecodedsampleisaduplicateofthestandard.
Whateverscorethepanellistassigntotheblindstandardis
subtractedfromthescoreheassigntothetestvariables.The
panellistisnottoguess.Directionanddegreeofdifferenceis
alsotobejudged.
FSN 501 (1+1) 34

35. Sample card
Name
Date
Product
You are given a standard or reference sample marked ”R”. Taste it carefully for the quality
characters to be evaluated. You are next given a no. of samples which are to be compared to
the reference sample for odour and flavour. Rate in each sample degree pf difference and the
direction of quality according to the following scale.
Degree of difference Direction of quality
Rating Difference from standard
0 None E-Equal
1 slight I-inferior
2 Moderate S-Superior
3 large
Sample code no. Odour Flavour
Degree direction comments Degree direction comments
Signature
FSN 501 (1+1) 35

36. B5. Hedonic rating test
Hedonicratingrelatestopleasurableorunpleasurable
experiences.
Thehedonicratingtestisusedtomeasuretheconsumer
acceptabilityoffoodproducts.
Askeachtastertotasteeachsampleinturnandticka
boxfromlikeextremelytodislikeextremely.
Theresultsareanalysedforpreferencewithdatafrom
largeuntrainedpanel.
FSN 501 (1+1) 36

37. Sample card
Name
Date
Product
Taste these samples and check how much you like or dislike each one. Use the appropriate scale to show
your attitude by checking at the point that best describes your feelings about the sample. Please give a
reason for this attitude.
code code code
Like extremely
Like very much
Like moderately
Like slight
Neither like nor dislike
Dislike slightly
Dislike moderately
Dislike very much
Dislike extremely
Reason
Signature
FSN 501 (1+1) 37

38. B6. Numerical scoring test
Oneormoresamplesarepresentedtoeach
panellistinrandomorderoraccordingtoa
statisticaldesign.
Thepanellistevaluateeachsampleonaspecific
scaleforaparticularcharacteristicindicatingthe
ratingofthesample.
Thepanellistaretrainedtofollowthesensory
characteristiccorrespondingtotheagreedquality
descriptionandscores.
FSN 501 (1+1) 38

39. Sample card
Name
Date
Product
Please rate these samples according to the following descriptions
Score Quality description
90 Excellent
80 Good
70 Fair
60 Poor
Sample score Comment
Signature
FSN 501 (1+1) 39

40. B7. Composite scoring test
Theratingscaleisdefinedsothatspecific
characteristicofaproductareratedseparately.
Thismethodishelpfulingradingproductsand
comparisonofqualityattributesbyindicating
whichcharacteristicisatfaultinapoorproduct.
Itgivesmoreinformationthanthestraight
numericalmethod.
FSN 501 (1+1) 40

41. Sample card
Name
Date
Product
Quality Possible score Sample score
Colour 20
Consistency 20
Flavour 4
Absence of defects 20
Total score 10
Signature
FSN 501 (1+1) 41

42. C SENSITIVITY TEST
C1 . Sensitivity threshold test
Threshold test is defined as a statistically determined point on
the stimulus scale at which a transition in a series of sensation or
judgements occur.
There are mainly three types of threshold
a. Stimulus detection threshold is that magnitude of stimulus at which a
transition occurs from no sensation to sensation.
b. Recognition identification threshold is the minimum concentration at
which a stimulus is correctly identified.
c . Terminal saturation threshold is the magnitude of a stimulus above
which there is no increase in the perceived intensity of the stimulus.
FSN 501 (1+1) 42

43. C2 . Dilution test
Dilutiontestsaredesignatedtoestablishthesmallest
amountofanunknownmaterial,developedasa
substituteforastandardproduct.
Thequalityofthetestmaterialisrepresentedbythe
dilutionnumber.
Thebiggerthedilutionnumberthebetteristhequalityof
thetestmaterial.
FSN 501 (1+1) 43

44. D. DESCRIPTIVE FLAVOUR PROFILE
METHOD
This is both qualitative and quantitative description for analysis in
products containing different tastes and odour .
For tomato ketchup the flavour profile analysis is given
Aroma Taste Mouth feelTexture
Garlic 1 Sour(Tea)1 Chillies(1)Smoothness(
3)
Pepper 2 Sweet(S)2
Onion 3 Salt 1
Cinnamon 2
Cloves 1
FSN 501 (1+1) 44

45. Limitations of sensory evaluation
1.Theresultmaybehighlyvariable.
2.Peoplewithcolorsorotherhealthproblemstemporarilylose
theirmaximumeffectiveness.
3.Emotionalburdensmayinfluenceanindividual’sability.
FSN 501 (1+1) 45

46. REFERENCE
FOOD SCIENCE B. SRILAKSHMI
FSN 501 (1+1) 46