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?