quality assessment postharvest

8/20/2019 Quality Assessment Postharvest

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QualityQualityQuality

• The degree of excellence or superiority

• Any of the features that make somethingwhat it is

•• The degree of excellence or superiorityThe degree of excellence or superiority

•• Any of the features that make something Any of the features that make somethingwhat it iswhat it is

Quality may be Defined DifferentlyQuality may be Defined DifferentlyQuality may be Defined Differently

• Producers

– Good appearance and few defects, high yield,disease resistance, ease of harvest

• Receivers and Marketers – Appearance quality is most important, also

firmness and long storage life

• Consumers – Good appearance, firm, good flavor and

nutritional content, safety

•• ProducersProducers

– – Good appearance and few defects, high yield,Good appearance and few defects, high yield,disease resistance, ease of harvestdisease resistance, ease of harvest

•• Receivers and MarketersReceivers and Marketers – – Appearance quality is most important, also Appearance quality is most important, also

firmness and long storage lifefirmness and long storage life

•• ConsumersConsumers – – Good appearance, firm, good flavor andGood appearance, firm, good flavor and

nutritional content, safetynutritional content, safety

Quality Factorsfor Fresh Horticultural CropsQuality FactorsQuality Factors

for Fresh Horticultural Cropsfor Fresh Horticultural Crops

• Appearance – visual• Texture – feel• Flavor – taste and smell• Aroma• Nutritional value• Safety

•• Appearance Appearance – – visualvisual

•• TextureTexture – – feelfeel

•• FlavorFlavor – – taste and smelltaste and smell

•• Aroma Aroma

•• Nutritional valueNutritional value

•• SafetySafety

Appearance – Visual Appearance Appearance – – Visual Visual

• Size• Shape and Form

– Ratio of diameter to length

– Smoothness

– Compactness

• Gloss – Lack of water loss

– Added wax

•• SizeSize

•• Shape and FormShape and Form – – Ratio of diameter to lengthRatio of diameter to length

– – SmoothnessSmoothness

– – CompactnessCompactness

•• GlossGloss – – Lack of water lossLack of water loss

– – Added wax Added wax

Size MeasurementSize MeasurementSize Measurement

• Dimensions – Length

– Width – Diameter

– Circumference

• Weight• Volume

•• DimensionsDimensions – – LengthLength

– – WidthWidth – – DiameterDiameter

– – CircumferenceCircumference

•• WeightWeight

•• Volume Volume


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Tools to Measure Product SizeTools to Measure Product Size

Shape of Various Cultivars of CarrotShape of Various Cultivars of Carrot Shape of Tomato FruitShape of Tomato Frui t

Color MeasurementColor MeasurementColor Measurement

• Visual assessment• Matching of colors

– Color charts or models

• Optical instrumentation – Light reflected or transmitted by commodity

• Chemical analysis for pigment content

•• Visual assessment Visual assessment

•• Matching of colorsMatching of colors

– – Color charts or modelsColor charts or models

•• Optical instrumentationOptical instrumentation – – Light reflected or transmitted by commodityLight reflected or transmitted by commodity

•• Chemical analysis for pigment contentChemical analysis for pigment content

Hue: red, purple, blue, green, yellow

Chroma: intensity of color

Value (L): Light to dark

Hue: red, purple, blue, green, yellowHue: red, purple, blue, green, yellow

ChromaChroma: intensity of color : intensity of color

Value (L): Light to darkValue (L): Light to dark

COLORCOLOR


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Minolta Colorimeter Minolta Colorimeter Minolta Colorimeter Appearance - Visual Appearance Appearance -- Visual Visual

• Defects – external or internal – Morphological

• Sprouting, rooting, floret opening

– Physical & mechanical• Shriveling, bruising

– Physiological• Blossom end rot of tomato, bitter pit of apple

– Pathological• Fungi, bacteria, viruses

– Entomological• Insects present

•• DefectsDefects – – external or internalexternal or internal – – MorphologicalMorphological

•• Sprouting, rooting, floret openingSprouting, rooting, floret opening

– – Physical & mechanicalPhysical & mechanical•• Shriveling, bruisingShriveling, bruising

– – PhysiologicalPhysiological•• Blossom end rot of tomato, bitter pit of appleBlossom end rot of tomato, bitter pit of apple

– – PathologicalPathological•• Fungi, bacteria, virusesFungi, bacteria, viruses

– – EntomologicalEntomological•• Insects presentInsects present

Examples of Defects that Do NotInfluence Postharvest Life Potentialof Fresh Produce

Examples of Defects thatExamples of Defects that Do NotDo Not

Influence Postharvest Life PotentialInfluence Postharvest Life Potential

of Fresh Produceof Fresh Produce

• Healed frost damage• Healed scars and scabs• Well healed insect stings• Irregular shape• Suboptimal color uniformity and intensity

•• Healed frost damageHealed frost damage•• Healed scars and scabsHealed scars and scabs

•• Well healed insect stingsWell healed insect stings

•• Irregular shapeIrregular shape

•• Suboptimal color uniformity and intensitySuboptimal color uniformity and intensity


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Examples of Defects that ReducePostharvest Life Potentialof Fresh Produce

Examples of Defects that ReduceExamples of Defects that Reduce

Postharvest Life PotentialPostharvest Life Potential

of Fresh Produceof Fresh Produce

• Softening• Sunburn & sunscald• Bruising• Cracks• Sprouting

•• SofteningSoftening

•• Sunburn & sunscaldSunburn & sunscald

•• BruisingBruising

•• CracksCracks

•• SproutingSprouting

• Chilling injury• Insect injury• Scald• Decay• Cuts, abrasions & skin

breaks

•• Chilling injuryChilling injury•• Insect injuryInsect injury

•• ScaldScald

•• DecayDecay

•• Cuts, abrasions & skinCuts, abrasions & skinbreaksbreaks

Scoring System for Visual QualityScoring System for Visual QualityScoring System for Visual Quality

SCORESCORE

99

77

55

33

11

DESCRIPTION

EXCELLENT: Field fresh, no defects

GOOD: Defects minor

FAIR: Defects moderate

POOR: Defects serious, limit of

salability

VERY POOR: Non-usable under usual

conditions

DESCRIPTIONDESCRIPTION

EXCELLENT: Field fresh, no defectsEXCELLENT: Field fresh, no defects

GOOD: Defects minorGOOD: Defects minor

FAIR: Defects moderateFAIR: Defects moderate

POOR: Defects serious, limit ofPOOR: Defects serious, limit of

salabilitysalability

VERY POOR: Non VERY POOR: Non--usable under usualusable under usual

conditionsconditions


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Texture – feel in hands or mouthTextureTexture – – feel in hands or mouthfeel in hands or mouth

• Firmness – Hardness, softness• Crispness• Succulence, juiciness• Mealiness, grittiness• Toughness, fibrousness

•• FirmnessFirmness

– – Hardness, softnessHardness, softness

•• CrispnessCrispness

•• Succulence, juicinessSucculence, juiciness

•• MealinessMealiness, grittiness, grittiness

•• Toughness, fibrousnessToughness, fibrousness

Texture MeasurementTexture MeasurementTexture Measurement

• Firmness or softness – Puncture (various sized tips)•Magness-Taylor pressure tester; Effegi

penetrometer

•May be mounted in a stand or automated – Compression or Deformation

•FirmTech, Instron – Acoustic measurement (non-destructive)

•• Firmness or softnessFirmness or softness

– – Puncture (various sized tips)Puncture (various sized tips)

••MagnessMagness--Taylor pressure tester;Taylor pressure tester; EffegiEffegipenetrometerpenetrometer

••May be mounted in a stand or automatedMay be mounted in a stand or automated – – Compression or DeformationCompression or Deformation

••FirmTechFirmTech,, InstronInstron

– – Acoustic measurement (non Acoustic measurement (non--destructive)destructive)

• Fibrousness or toughness – Shear force

– Resistance to cutting (Fibrometer)

– Chemical analysis of fiber or lignin content

• Succulence and juiciness – Water content or extractable juice

• Sensory textural quality – Grittiness, crispness, mealiness, chewiness,

oiliness

•• Fibrousness or toughnessFibrousness or toughness – – Shear forceShear force

– – Resistance to cutting (Resistance to cutting (FibrometerFibrometer))

– – Chemical analysis of fiber or lignin contentChemical analysis of fiber or lignin content

•• Succulence and juicinessSucculence and juiciness – – Water content or extractable juiceWater content or extractable juice

•• Sensory textural qualitySensory textural quality – – Grittiness, crispness,Grittiness, crispness, mealinessmealiness,, chewinesschewiness,,

oilinessoiliness

Texture MeasurementTexture MeasurementTexture Measurement Drill Stand MountedPenetrometer

Drill Stand MountedDrill Stand Mounted

Penetrometer Penetrometer

Fruit Texture AnalyzerGüss ManufacturingSouth Africa

Fruit Texture AnalyzerFruit Texture Analyzer

GGüüssss ManufacturingManufacturing

South AfricaSouth Africa

FirmTech1 Firmness Tester FirmTech1 Firmness Tester FirmTech1 Firmness Tester


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Flavor – Taste and SmellFlavorFlavor – – Taste and SmellTaste and Smell

• Sweetness• Sourness – acidity• Astringency• Bitterness• Aroma – volatile compounds• Off-flavors• Off-odors

•• SweetnessSweetness

•• SournessSourness – – acidityacidity

•• Astringency Astringency

•• BitternessBitterness

•• Aroma Aroma – – volatile compoundsvolatile compounds

•• Off Off --flavorsflavors

•• Off Off --odorsodors

Measurement of Total Soluble Solids by Refractometer Measurement of Total Soluble Solids b yMeasurement of Total Soluble Solids by Refractometer Refractometer

Composition ofComposition of ‘ ‘SeascapeSeascape’ ’ StrawberriesStrawberries

100.0100.09.209.20Total SSTotal SS

32.132.12.952.95OthersOthers

10.610.60.970.97Total acidsTotal acids

2.22.20.200.20MalicMalic acidacid

8.48.40.770.77Citric acidCitric acid

57.357.35.285.28Total sugarsTotal sugars

16.916.91.561.56FructoseFructose

16.716.71.541.54GlucoseGlucose

23.723.72.182.18SucroseSucrose

Percent of TSSPercent of TSSMean conc. (%)Mean conc. (%)ConstituentConstituent

What are the Other Constituents?What are the Other Constituents?

32.132.12.952.95TotalTotal

2.12.10.190.19PhenolicsPhenolics

2.32.30.210.21 Ascorbic acid Ascorbic acid

6.56.50.600.60SolubleSoluble pectinspectins

21.221.21.951.95 Anthocyanins Anthocyanins

% of TSS% of TSSContribution toContribution to

refractometerrefractometer readingreadingConstituentConstituent


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Aroma Aroma Aroma

Esters

AldehydesKetones

EstersEsters

Aldehy des AldehydesKetonesKetones

Sweetness .27 .76** .64**

Sourness .89** .30 .10

Tomato-like -.01 .52** .42**

Overall .88** .60** .38*

SweetnessSweetness .27.27 .76**.76** .64**.64**

SournessSourness .89**.89** .30.30 .10.10

TomatoTomato--likelike --.01.01 .52**.52** .42**.42**

OverallOverall .88**.88** .60**.60** .38*.38*

SolubleTitratable solids Reducing

Sensory acidity content sugars

SolubleSolubleTitratableTitratable solidssolids ReducingReducing

SensorySensory acidityacidity contentcontent sugarssugars

Relationship of Sensory Quality

to Objective Quality Measurements

in Tomato Fruit

Relationship of Sensory QualityRelationship of Sensory Quality

to Objective Quality Measurementsto Objective Quality Measurements

in Tomato Fruitin Tomato Fruit

Sensory Evaluation of Product QualitySensory Evaluation of Product QualitySensory Evaluation of Product Quality Consumer Taste TestConsumer Taste TestConsumer Taste Test

Nutritive ValueNutritive ValueNutritive Value

• Carbohydrates – Including dietary fiber

• Proteins

• Lipids• Vitamins• Minerals• Phytonutrients

– Antioxidants

– Flavonoids

•• CarbohydratesCarbohydrates – – Including dietary fiberIncluding dietary fiber

•• ProteinsProteins

•• LipidsLipids•• Vitamins Vitamins

•• MineralsMinerals

•• PhytonutrientsPhytonutrients – – Antioxidants Antioxidants

– – FlavonoidsFlavonoids

http://www.mypyramid.gov/http://http://www.mypyramid.govwww.mypyramid.gov//

Emphasizesfruits,

vegetables,whole grains,

and fat-free or

low-fat milk andmilk products


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Potential Health Benefits of Fruitsand VegetablesPotential Health Benefits of FruitsPotential Health Benefits of Fruits

and Vegetablesand Vegetables

Constituents• Antioxidants – Vitamins A, C & E

– Flavonoids

• Fiber• Folate

• Potassium

ConstituentsConstituents•• Antioxidants Antioxidants – – Vitamins A, C & E Vitamins A, C & E

– – FlavonoidsFlavonoids

•• FiberFiber

•• FolateFolate

•• PotassiumPotassium

Impacted Human Diseases

• Cancer, cataracts, heartdisease, stroke

• Diabetes, heart disease• Birth defects, cancer, heart

disease

• Hypertension, stroke

Impacted Human DiseasesImpacted Human Diseases

•• Cancer, cataracts, heartCancer, cataracts, heartdisease, strokedisease, stroke

•• Diabetes, heart diseaseDiabetes, heart disease

•• Birth defects, cancer, heartBirth defects, cancer, heartdiseasedisease

•• Hypertension, strokeHypertension, stroke

SafetySafetySafety

• Naturally occurring toxicants – Glycoalkaloids in potatoes• Contaminants

– Chemical residues, heavy metals

• Mycotoxins – Produced by certain fungi

• Microbial contamination

•• Naturally occurring toxicantsNaturally occurring toxicants

– – GlycoalkaloidsGlycoalkaloids in potatoesin potatoes

•• ContaminantsContaminants – – Chemical residues, heavy metalsChemical residues, heavy metals

•• MycotoxinsMycotoxins – – Produced by certain fungiProduced by certain fungi

•• Microbial contaminationMicrobial contamination

Questions?Questions?Questions?

quality assessment postharvest

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