sensory evaluation of food tutorial 2

8/20/2019 Sensory Evaluation of Food Tutorial 2

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Sensory Evaluation of FoodsSensory Evaluation of FoodsAlexandra OliveiraAlexandra Oliveira

Associate Professor Seafood ChemistryAssociate Professor Seafood ChemistryFITCFITC-- SFOSSFOS

University of AlaskaUniversity of Alaska

FISH 261FISH 261 –– SpringSpring 20112011


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Human SensesHuman Senses

•• Many accepted definitionsMany accepted definitions

–– SensesSenses are the physiological methods ofare the physiological methods of perceperceptionption

•• AristotleAristotle –– There areThere are five sensesfive senses in humans:in humans:

–– SightSight–– HearingHearing

–– TouchTouch

–– SmellSmell

–– TasteTaste

http://en.wikipedia.org/wiki/Senses


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•• From neurological SciencesFrom neurological Sciences -- Humans have at least sixHumans have at least six

additional senses (at least 11 senses all together):additional senses (at least 11 senses all together):

–– NociceptionNociception –– painpain

–– EquilibraceptionEquilibraception –– balancebalance

–– ProprioceptionProprioception and kinesthesiaand kinesthesia -- joint motion andjoint motion and

accelerationacceleration

–– Sense of timeSense of time

–– ThermoceptionThermoception -- temperature differencestemperature differences

–– MagnetoceptionMagnetoception –– direction (weak in many individuals)direction (weak in many individuals)

•• From all the senses above the only one that mayFrom all the senses above the only one that may

influence sensory evaluation of a food item isinfluence sensory evaluation of a food item isthermoceptionthermoception



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•• Commonly recognized categorization for humanCommonly recognized categorization for human

senses is:senses is:–– ChemoreceptionChemoreception (taste and smell)(taste and smell)

–– PPhotoreceptionhotoreception (sight)(sight)

–– MMechanoreceptionechanoreception (touch)(touch)–– TThermoceptionhermoception ((thermoceptionthermoception))

•• All human senses fit into one of the categories listedAll human senses fit into one of the categories listed

aboveabove



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•• SightSight oror vision:vision:

–– Ability of the brain and eye to detectAbility of the brain and eye to detect electromagneticelectromagneticwaveswaves within the visible range (within the visible range (lightlight) and interpret the) and interpret the

imageimage

•• Touch,Touch, mechanoreceptionmechanoreception oror somatic sensation:somatic sensation:–– Sense of pressure perception, generally in theSense of pressure perception, generally in the skinskin

•• HearingHearing oror audition:audition:

–– Sense ofSense of soundsound perceptionperception

–– Sound is vibrations propagating through a medium (e.g. air)Sound is vibrations propagating through a medium (e.g. air)

––

Detection of these vibrations is a mechanical sense similarDetection of these vibrations is a mechanical sense similar

toto ‘‘touchtouch’’ but much more specializedbut much more specializedhttp://en.wikipedia.org/wiki/Senses


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•• TasteTaste oror gustationgustation::

–– This is a "chemical" senseThis is a "chemical" sense

–– There four main types of tastes that receptorsThere four main types of tastes that receptors

(buds) in the(buds) in the tonguetongue can distinguish:can distinguish:

•• SweetSweet•• SaltSalt

•• SourSour

•• BitterBitter



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•• TasteTaste oror gustationgustation::

–– In 1908 a fifth receptor, for a sensation calledIn 1908 a fifth receptor, for a sensation called

umamiumami (SAVORIENESS)(SAVORIENESS), was first theorized. In 200, was first theorized. In 200

its existence was confirmed.its existence was confirmed.

•• TheThe umamiumami receptor detects thereceptor detects the amino acidamino acid glutamate,glutamate,a flavor commonly found in meat and in artificiala flavor commonly found in meat and in artificial

flavorings such as monosodium glutamate (MSG)flavorings such as monosodium glutamate (MSG)

–– Most of what we perceive (or describe as taste) isMost of what we perceive (or describe as taste) isactually smellactually smell

•• E.g.E.g. ““This iceThis ice--cream tastes like strawberry and bananacream tastes like strawberry and banana””;;

it actually smells like banana and possibly tastes sweetit actually smells like banana and possibly tastes sweetand sourand sour



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Sense of TasteSense of Taste –– Our TongueOur Tongue•• The majority of taste buds on the tongue sit on raisedThe majority of taste buds on the tongue sit on raised

protrusions of the tongue surface called papillae. Four typesprotrusions of the tongue surface called papillae. Four typesof papillae present in the human tongue:of papillae present in the human tongue:

•• FungiformFungiform papillaepapillae -- SlightlySlightly mushroommushroom--shaped if looked at inshaped if looked at inlongitudinal section. These are present mostly at the apexlongitudinal section. These are present mostly at the apex

(tip) of the tongue, as well as at the sides(tip) of the tongue, as well as at the sides•• FiliformFiliform papillaepapillae -- Thin, long papillae "V"Thin, long papillae "V"--shaped cones thatshaped cones that

don't contain taste buds but are the most numerous. Thesedon't contain taste buds but are the most numerous. Thesepapillae are mechanical and not involved inpapillae are mechanical and not involved in gustationgustation

•• Foliate papillaeFoliate papillae -- Ridges and grooves towards the posteriorRidges and grooves towards the posteriorpart of the tongue found on lateral marginspart of the tongue found on lateral margins

•• CircumvallateCircumvallate papillaepapillae -- Only about 3Only about 3--14 of these papillae on14 of these papillae on

most people. Present at the back of the oral part of themost people. Present at the back of the oral part of thetongue. Arranged in a circulartongue. Arranged in a circular--shapedshaped

http://en.wikipedia.org/wiki/Taste

http://en.wikipedia.org/wiki/Fungiform_papillaehttp://en.wikipedia.org/wiki/Fungiform_papillaehttp://en.wikipedia.org/wiki/Fungiform_papillaehttp://en.wikipedia.org/wiki/Fungiform_papillaehttp://en.wikipedia.org/wiki/Mushroomhttp://en.wikipedia.org/wiki/Mushroomhttp://en.wikipedia.org/wiki/Filiform_papillaehttp://en.wikipedia.org/wiki/Filiform_papillaehttp://en.wikipedia.org/wiki/Filiform_papillaehttp://en.wikipedia.org/wiki/Filiform_papillaehttp://en.wiktionary.org/wiki/gustationhttp://en.wiktionary.org/wiki/gustationhttp://en.wiktionary.org/wiki/gustationhttp://en.wikipedia.org/wiki/Foliate_papillaehttp://en.wikipedia.org/wiki/Foliate_papillaehttp://en.wikipedia.org/wiki/Circumvallate_papillaehttp://en.wikipedia.org/wiki/Circumvallate_papillaehttp://en.wikipedia.org/wiki/Circumvallate_papillaehttp://en.wikipedia.org/wiki/Circumvallate_papillaehttp://upload.wikimedia.org/wikipedia/commons/4/4c/Illu04_tongue.jpghttp://en.wikipedia.org/wiki/Circumvallate_papillaehttp://en.wikipedia.org/wiki/Circumvallate_papillaehttp://en.wikipedia.org/wiki/Foliate_papillaehttp://en.wiktionary.org/wiki/gustationhttp://en.wikipedia.org/wiki/Filiform_papillaehttp://en.wikipedia.org/wiki/Filiform_papillaehttp://en.wikipedia.org/wiki/Mushroomhttp://en.wikipedia.org/wiki/Fungiform_papillaehttp://en.wikipedia.org/wiki/Fungiform_papillae


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Sense of TasteSense of Taste –– TasteTaste BudsBuds

View of a portion of the mucous membrane of the tongue.

Two fungiform papillæ are shown.

On some of the filiform papillæ the epithelial prolongations

stand erect, in one they are spread out, and in three they

are folded in.

Contrary to popular understanding that

different tastes map to different areas

of the tongue, taste qualities are found

in all areas of the tongue

although some regions are more

sensitive than others

http://en.wikipedia.org/wiki/Taste

http://en.wikipedia.org/wiki/File:Gray1018.pnghttp://upload.wikimedia.org/wikipedia/commons/0/0e/Taste_bud.svg


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•• SmellSmell oror olfactionolfaction–– This is aThis is a ““chemical" sensechemical" sense

–– Unlike taste, there are hundreds of olfactoryUnlike taste, there are hundreds of olfactoryreceptors in our olfactory epithelium (where thereceptors in our olfactory epithelium (where thereceptor are located)receptor are located)

–– Odor molecules have a variety of features and canOdor molecules have a variety of features and cancombine with many or few receptorscombine with many or few receptors

–– It is known that there isnIt is known that there isn’’t one receptor fort one receptor forspecific kinds of smells, our sense of smell worksspecific kinds of smells, our sense of smell works

withwith ‘‘patter recognitionpatter recognition’’



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•• SmellSmell oror olfactionolfaction–– This combination of signals from differentThis combination of signals from different

receptors makes up what we perceive as smell ofreceptors makes up what we perceive as smell ofsubstances or mixtures of substances (volatiles)substances or mixtures of substances (volatiles)

–– Volatiles are molecules of low boiling point atVolatiles are molecules of low boiling point atatmospheric pressure (1atmospheric pressure (1 atmatm or 760or 760 mmgmmg Hg)Hg)

•• Note: Taste is not the same as flavor!Note: Taste is not the same as flavor!

•• Flavor includes theFlavor includes the smellsmell of a food as well asof a food as well as

itsits tasttast–– In the strawberryIn the strawberry--banana icebanana ice--cream example thecream example thecorrect description would becorrect description would be ‘‘This cream has aThis cream has astrawberrystrawberry--banana flavorbanana flavor’’



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Sense of SmellSense of Smell -- Our NoseOur Nose

http://www.senseofsmell.org/feature/smell101/lesson1/01.php


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About the Trigeminal NerveAbout the Trigeminal Nerve

•• Sensation of cooling (e.g. menthol, mint) or hot (e.g.Sensation of cooling (e.g. menthol, mint) or hot (e.g.

cinnamon or clove) in back of our throats is not partcinnamon or clove) in back of our throats is not partofof ‘‘tastetaste’’ but a response to stimulus in the trigeminalbut a response to stimulus in the trigeminal

nervenerve

–– Trigeminal nerve = fifth cranial nerveTrigeminal nerve = fifth cranial nerve•• Responsible for sensation in the faceResponsible for sensation in the face

•• The fifth nerve is primarily aThe fifth nerve is primarily a sensory sensory nerve, but it also has certainnerve, but it also has certain

motor motor functions (biting, chewing, and swallowing)functions (biting, chewing, and swallowing)

•• There are two basic types of sensation:There are two basic types of sensation: touch/positiontouch/position andand

pain/temperaturepain/temperature


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About the Trigeminal NerveAbout the Trigeminal Nerve

http://www.clinicalexams.co.uk/images/trigeminal_nerve_5.jpg


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What is Sensory Analysis?What is Sensory Analysis?

•• Identification of food product (s) propertiesIdentification of food product (s) properties

•• Scientific measurement of food product (s) propertiesScientific measurement of food product (s) properties

•• Analysis and interpretation of the identified andAnalysis and interpretation of the identified and

measured food product propertiesmeasured food product properties

–– AS THERE ARE PERCIVED THROUGH THE FIVE SENSES:AS THERE ARE PERCIVED THROUGH THE FIVE SENSES:-- sight (e.g. color of a food product)sight (e.g. color of a food product)

-- smell (e.g. presence of rancidity in a product)smell (e.g. presence of rancidity in a product)

-- taste (e.g. intensity of sweetness)taste (e.g. intensity of sweetness)

-- touch (e.g. firmness of a muscle food)touch (e.g. firmness of a muscle food)

-- hearing (e.g. crunchiness of a potato chip)hearing (e.g. crunchiness of a potato chip)


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What Questions Sensory Analysis Answer?What Questions Sensory Analysis Answer?

•• Questions that deals with quality of food productsQuestions that deals with quality of food products

underunder

threethree

main categories:main categories:

–– DiscriminationDiscrimination

•• These questions have the objective of determining ifThese questions have the objective of determining ifdifferences exist between two or more productsdifferences exist between two or more products

•• Type of questions that may be asked in discriminationType of questions that may be asked in discriminationsensory tests:sensory tests:

–– Is product A identical to product B?Is product A identical to product B?

–– Find the two similar products among the threeFind the two similar products among the threesamples providessamples provides

–– Find the odd sample among the three samplesFind the odd sample among the three samples

providedprovided


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•• Questions that deals with quality of food productsQuestions that deals with quality of food products

underunder threethree main categories:main categories:–– DescriptionDescription

•• These questions have the objective of describingThese questions have the objective of describing

characteristics of a product and/or measuring anycharacteristics of a product and/or measuring anydifferences that are found between productsdifferences that are found between products

–– What does this product taste like?What does this product taste like?

–– What are the three most important textureWhat are the three most important textureattributes you perceive in this product?attributes you perceive in this product?

–– For which sensory attributes are the differencesFor which sensory attributes are the differences

between product A and B most marked?between product A and B most marked?


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•• Questions that deals with quality of food products underQuestions that deals with quality of food products under threethreemain categories:main categories:

–– Preference or HedonicsPreference or Hedonics

•• These questions have the objective of describing likingThese questions have the objective of describing likingor acceptability of a productor acceptability of a product

–– Do you like this product? How much do you like thisDo you like this product? How much do you like thisproduct on a scale of 1 to 10, where 1 = dislikeproduct on a scale of 1 to 10, where 1 = dislikeextremely, and 10 = like extremely?extremely, and 10 = like extremely?

–– Is this product acceptable?Is this product acceptable?–– What do you like most about this product?What do you like most about this product?

–– Is product A better then product B?Is product A better then product B?

–– Which of the three products A, B and C do youWhich of the three products A, B and C do youprefer?prefer?


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Why Use Sensory Analysis to EvaluateWhy Use Sensory Analysis to Evaluate

Food Products?Food Products?•• To evaluate quality (quality control) or improveTo evaluate quality (quality control) or improve

qualityquality–– E.g. Maintain a product with same sensorial characteristicsE.g. Maintain a product with same sensorial characteristics

so consumers of that product continue to buy itso consumers of that product continue to buy it

–– E.g. Release production batch for sale because theE.g. Release production batch for sale because the

products inspected meet the standards set by theproducts inspected meet the standards set by themanufacturermanufacturer

–– E.g. Reject production batch because the productsE.g. Reject production batch because the products

inspected are below the acceptable level of quality set byinspected are below the acceptable level of quality set bythe manufacturerthe manufacturer

•• To provide input for decision making (productTo provide input for decision making (product

development)development)–– E.g. Launching a new fruit snack, or a new flavor fish stickE.g. Launching a new fruit snack, or a new flavor fish stick


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Food Products?Food Products?•• To determine the market value of a productTo determine the market value of a product

––

E.g. Determine value of perishable products such as fish. IfE.g. Determine value of perishable products such as fish. Iffish is very fresh and was handled with great care, then itfish is very fresh and was handled with great care, then itis likely to be sold for a higher price then frozen fish thatis likely to be sold for a higher price then frozen fish thathas kept in frozen storage for 6 monthshas kept in frozen storage for 6 months

•• To determine shelf To determine shelf --life of a productlife of a product–– E.g. How long can a cracker remain in the groceries shelvesE.g. How long can a cracker remain in the groceries shelves

before it becomes stale?before it becomes stale?

•• Ingredient substitution in product formulationIngredient substitution in product formulation–– E.g. Cost reduction of a product formulation byE.g. Cost reduction of a product formulation by

substitution of ingredient A for ingredient B. Does it changesubstitution of ingredient A for ingredient B. Does it change

the product? Can the consumer perceive it? How does itthe product? Can the consumer perceive it? How does itchanges the product?changes the product?


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Food Products?Food Products?•• To compare a product (s) with the competitorTo compare a product (s) with the competitor‘‘ss

product (s)product (s)

–– E.g. How close in taste is beverage A produced by companyE.g. How close in taste is beverage A produced by company

A as it compares to beverage B produced by company B?A as it compares to beverage B produced by company B?

•• To determine storage conditionsTo determine storage conditions–– Should the product be stored refrigerated, frozen or atShould the product be stored refrigerated, frozen or at

room temperature?room temperature?

–– Will the product become rancid very quickly if it sits atWill the product become rancid very quickly if it sits atroom temperature? (butter; cheeseroom temperature? (butter; cheese……))

–– Will the product change texture, appearance or taste if itWill the product change texture, appearance or taste if it

is stored frozen? (eggs; milkis stored frozen? (eggs; milk……))


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Sensory Evaluation PitfallsSensory Evaluation Pitfalls

•• Determining the wrong objective for conductingDetermining the wrong objective for conducting

sensory analysissensory analysis•• Choosing the wrong set of participants in the sensoryChoosing the wrong set of participants in the sensory

test(stest(s))

•• Asking the wrong questions to the participantsAsking the wrong questions to the participants

•• Having biased judgments of the products testedHaving biased judgments of the products tested

•• Lacking scientific control (scientific rigor)Lacking scientific control (scientific rigor)•• Conducting the sensory test in the wrongConducting the sensory test in the wrong

(inadequate) environment(inadequate) environment


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Sensory Panel RoomsSensory Panel Rooms

h t t p : / / i m a g

e s . g o o g l e . c o m / i m a g e

s ? h l = e n & r l z = 1 G 1 G G L

Q_

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e l + r o o m & u m =

1 & i e = U T F - 8 & e i = h e n e S b z t A Y S o

t A P N 8 P S x C Q & s a = X &

o i = i m a g e_

r e s u l t_

g r o u p & r e s n u m = 1 & c t = t i t l e

http://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&umhttp://images.google.com/images?hl=en&rlz=1G1GGLQ_ENUS309&q=pictures+of+sensory+panel+room&um


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Sensory Panel RoomSensory Panel Room

•• Round tableRound table –– mostly for product development (e.g.mostly for product development (e.g.launching new product; change in productlaunching new product; change in productformulation) and internal sensory assessment (e.g.formulation) and internal sensory assessment (e.g.consumer complain)consumer complain)

•• Booths are widely used to provide an environmentBooths are widely used to provide an environmentthat prevents panelists from being distracted andthat prevents panelists from being distracted andinteracting with other panelistsinteracting with other panelists –– unbiased evaluationunbiased evaluation

–– Booths can be computerized so panelists enter the answersBooths can be computerized so panelists enter the answersto the sensory assessment questions electronicallyto the sensory assessment questions electronically

–– Booths may have features that change environmentalBooths may have features that change environmentalconditions such as different colors of light to mask productconditions such as different colors of light to mask product

colorcolor


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•• Noise level should be kept lowNoise level should be kept low

•• Room should be free of foreign odorsRoom should be free of foreign odors•• Testing are should be well lit and ventilatedTesting are should be well lit and ventilated

•• Testing area should be easy to clean and disinfectTesting area should be easy to clean and disinfect

(sanitation)(sanitation)

•• Temperature and relative humidity should beTemperature and relative humidity should be

constant and controllableconstant and controllable•• The room where food products are prepared forThe room where food products are prepared for

sensory testing is generally separated from thesensory testing is generally separated from the

testing areatesting area


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•• Large room normally are used for testing productsLarge room normally are used for testing products

using consumersusing consumers –– Untrained panelistsUntrained panelists•• Panelists (participants) can be trained to evaluatePanelists (participants) can be trained to evaluate

specific products (odor, taste, texture, and or visualspecific products (odor, taste, texture, and or visual

evaluation)evaluation)•• At time before training panelists are screened forAt time before training panelists are screened for

sensitivity in order to remove from the group ofsensitivity in order to remove from the group of

panelists people that may not have the ability topanelists people that may not have the ability to

perform the sensory evaluation (e.g. people withperform the sensory evaluation (e.g. people with

specific type ofspecific type of anosmiaanosmia –– inability to smell certaininability to smell certainodors)odors)


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Sensory Analysis QuestionnairesSensory Analysis Questionnaires

•• It needs to address the main question being testedIt needs to address the main question being tested

•• Questionnaires are variable and need to be design inQuestionnaires are variable and need to be design ina simple, practical way to yield clear and concisea simple, practical way to yield clear and concise

answersanswers

•• When designing a sensory questionnaire (also called aWhen designing a sensory questionnaire (also called asensory ballot), one needs to take into considerationsensory ballot), one needs to take into consideration

the audience (panelists)the audience (panelists)

–– E.g. children vs. adults, trained panelists vs. untrainedE.g. children vs. adults, trained panelists vs. untrained

panelists, etcpanelists, etc……


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Triangle Sensory Test on Cookies

Please take a drink of water before

tasting

cookie samples. Eat cookie samples

from left

to right, and please take a sip of

water

between samples. Place an “ X”under the

cookie which is different than the

others.

767 312 189 ___ ___ ___

Comments:


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Types of Sensory TestsTypes of Sensory Tests

•• DISCRIMINATION TESTSDISCRIMINATION TESTS

••

Paired Comparison TestsPaired Comparison Tests

––

Testing for differences betweenTesting for differences between

two samplestwo samples

–– Simple test: request panelist to taste two samples and respond iSimple test: request panelist to taste two samples and respond if thef the

samples are identical or differentsamples are identical or different

–– More complex tests can involve differences is specific attributeMore complex tests can involve differences is specific attributes) suchs) suchas sweetness, bitterness, type of odor..as sweetness, bitterness, type of odor..

•• DuoDuo--TrioTrio –– Panelists evaluates three samples, and one of themPanelists evaluates three samples, and one of them

is marked as reference. Panelist is asked to pick the sampleis marked as reference. Panelist is asked to pick the samplethat is closer in taste, odor, etc.. To the reference samplethat is closer in taste, odor, etc.. To the reference sample

•• Triangle TestTriangle Test –– Panelists evaluates three samples, two arePanelists evaluates three samples, two are

identical and one if different. Panelist is requested to pick thidentical and one if different. Panelist is requested to pick theesample that is differentsample that is different


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Types of Sensory TestsTypes of Sensory Tests

•• DESCRIPTIVE SENSORY ANALYSISDESCRIPTIVE SENSORY ANALYSIS

–– Useful when a detailed specification of the sensoryUseful when a detailed specification of the sensoryattributes of a product is desirableattributes of a product is desirable

–– Also, it can be useful for comparisons between productsAlso, it can be useful for comparisons between products

when descriptions of differences are neededwhen descriptions of differences are needed–– Normally uses trained panelistsNormally uses trained panelists

–– Some of descriptive sensory analysis methods:Some of descriptive sensory analysis methods:

•• Flavor ProfileFlavor Profile; Quantitative Descriptive Analysis (QDA); Quantitative Descriptive Analysis (QDA) , Texture, TextureProfileProfile ; Sensory Spectrum; Sensory Spectrum ; Generic Descriptive Analysis; Free; Generic Descriptive Analysis; Free--

choice Profiling, etcchoice Profiling, etc……


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Types of ScalesTypes of Scales

•• Many types of scales availableMany types of scales available……

••

Numerical scaleNumerical scale

–– E.g. Intensity: (weak) 1 2 3 4 5 6 7 8 9 (strongE.g. Intensity: (weak) 1 2 3 4 5 6 7 8 9 (strong))

•• Verbal categorical scalesVerbal categorical scales

–– E.g. Oxidized flavor: not noticeable; trace; faint; mild; moderaE.g. Oxidized flavor: not noticeable; trace; faint; mild; moderate,te,

strong, very strongstrong, very strong

•• Ranking or ordering scalesRanking or ordering scales

–– E.g. Preference between products A, B, C: 1 most preferred, 2E.g. Preference between products A, B, C: 1 most preferred, 2

intermediate preference; 3 least preferredintermediate preference; 3 least preferred

•• Magnitude of differences (interval scale, see sturgeonMagnitude of differences (interval scale, see sturgeon

example slide 8)example slide 8)

•• Hedonic scaling for children (Hedonic scaling for children (‘‘smiley face modelsmiley face model’’))


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Quality Index Method and Fish freshnessQuality Index Method and Fish freshness

•• QIM was designed to standardize the method toQIM was designed to standardize the method toevaluate fish freshness for different fish speciesevaluate fish freshness for different fish species

•• It is a method that takes in consideration the sensoryIt is a method that takes in consideration the sensoryattributes that different fish species haveattributes that different fish species have

•• Uses well defined experimental conditionsUses well defined experimental conditions•• Uses trained panelistsUses trained panelists

•• It is based on the calculation of aIt is based on the calculation of a ““Quality IndexQuality Index””

that is determined from the scores given for athat is determined from the scores given for aproduct for each attribute evaluated. E.g.product for each attribute evaluated. E.g.appearance of the gills, firmness of the fish muscle,appearance of the gills, firmness of the fish muscle,

dullness of the eyes, fillet color, etcdullness of the eyes, fillet color, etc……

sensory evaluation of food tutorial 2

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