Nondestructive Texture Assessment of Fruits and Vegetables by Itzhak Shmulevich Unlimited Postharvesting Leuven June 11-14, 2002.

Nondestructive Texture Assessment Nondestructive Texture Assessment of Fruits and Vegetablesof Fruits and Vegetables

by by

Itzhak ShmulevichItzhak Shmulevich

Unlimited PostharvestingUnlimited PostharvestingLeuven June 11-14, 2002Leuven June 11-14, 2002

The Department of The Department of Agricultural Agricultural EngineeringEngineeringTechnion-Israel Institute of TechnologyTechnion-Israel Institute of Technology

Technion-Israel Institute of Technology The Department of Civil &

Environmental Engineering,

Agricultural Engineering Option

Presentation outlinePresentation outline

Introduction - firmness quality nondestructive measurements;

Impact technique vs. acoustic technique; Experimental report on various fruits; Results;

Discussion;

Conclusions.

QUALITY QUALITY ASSESSMENTASSESSMENT

Quality Factors of Quality Factors of Agricultural ProductsAgricultural Products

AppearanceAppearance - visual- visual Texture Texture - feel- feel Flavor Flavor - taste and smell- taste and smell SafetySafety Nutritive ValueNutritive Value

TextureTexture

Texture can be defined by subjective Texture can be defined by subjective terms such as:terms such as:

Firmness Firmness Mealiness, Hardness, Softness, Mealiness, Hardness, Softness, Brittleness, Ripeness, Toughness, Brittleness, Ripeness, Toughness, Chewiness, Smoothness, Crispness, Chewiness, Smoothness, Crispness, Oiliness, Springiness, Toughness, Oiliness, Springiness, Toughness, Fibrousness, or Juiciness etc.Fibrousness, or Juiciness etc.

Quality Sensing in Quality Sensing in Commercial SettingsCommercial Settings

RequirementsRequirements

NondestructiveNondestructive

External and internal propertiesExternal and internal properties

AccuracyAccuracy

Speed (5-15 fruits/sec)Speed (5-15 fruits/sec)

Recognize inherent product variabilityRecognize inherent product variability

NONDESTRUCTIVE NONDESTRUCTIVE

SENSOR SENSOR TECHNOLOGYTECHNOLOGY

NondestructiveNondestructive Firmness Firmness Measurement TechniquesMeasurement Techniques

Fruit Response to ForceFruit Response to Force Detection by Impact ForceDetection by Impact Force Forced VibrationsForced Vibrations Mechanical or Sonic ImpulseMechanical or Sonic Impulse Ultrasonic TechniquesUltrasonic Techniques Indirect Firmness MeasurementIndirect Firmness Measurement

Research Research ObjectiveObjective

The motivation of the present work is to develop

a fast nondestructive method for quality firmness

testing of fruit and vegetable.

The general objective of the research is to

compare sensing the fruitfirmness using low

mass impulse excitation to the acoustic response

For quality assessment of fruit and vegetable.

TextureTexture

Relationship between turgor Relationship between turgor pressure and tissue rigiditypressure and tissue rigidity

E=3.6 p +2.5 x10E=3.6 p +2.5 x1077 [ dynes/cm [ dynes/cm22]]

Modulus of ElasticityModulus of Elasticity

NondestructiveNondestructive Firmness Firmness MeasurementMeasurement

Impact Force TechniqueImpact Force Technique

NondestructiveNondestructive Firmness Firmness MeasurementMeasurement

Acoustic TechniqueAcoustic Technique

Method and Method and MaterialsMaterials• Mango (210) Kent cultiver;Mango (210) Kent cultiver;

• Shelf life conditions: 20 Shelf life conditions: 20 00C 50%RH;C 50%RH;

• 12 days, ( 10 experiments):12 days, ( 10 experiments): 80 fruit were tested daily only 80 fruit were tested daily only nondestructivelynondestructively 130 fruit were tested both 130 fruit were tested both nondestructively and nondestructively and destructively 12 fruit were tested destructively 12 fruit were tested daily;daily;

• Special experimental set up for input Special experimental set up for input and outputand output signals measurements;signals measurements;

• Brix by digital refractometer, Atago's Palette 100.Brix by digital refractometer, Atago's Palette 100.

.

Low-Mass Impact (LMI) Low-Mass Impact (LMI) FirmnessFirmness

IQ FirmnessIQ Firmness

IQ IQ TM TM Firmness Tester Firmness Tester

Sinclair International Sinclair International LTDLTD

DestructiveDestructive Firmness Firmness

MeasurementMeasurement

Destructive TestsDestructive Tests

Destructive TestsDestructive Tests

Quality Detection by Quality Detection by Impact ForceImpact Force

Time [msec]

Force[N]

22

p

p

T

FC

p

p

T

FC 1

1.5 2 2.5 3 3.5

x 10-3

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Time [sec]

Am

plit

ude [

volt]

d

sec

N

Fp

Tp

td

Quality Detection by Impact Quality Detection by Impact ForceForceChen. P (1996), Farabee (1991)

Delwiche (1989 ,1991), Nahir et al. (1986 )

The Acoustic The Acoustic Parameters Parameters

of a Fruitof a Fruit Natural frequencies and firmness index - Natural frequencies and firmness index - FIFI

FI = f FI = f 22 m m 2/32/3 {10{104 4 kgkg2/32/3 s s-2-2} }

where: where: f f - first spherical resonant frequency - first spherical resonant frequency

mm - fruit’s mass. - fruit’s mass. Damping ratio - Damping ratio - The centeroid of the frequency response - The centeroid of the frequency response - ffcc

Firmalon PrototypeFirmalon Prototype

FirmalonFirmalon

Typical Acoustic Fruit Typical Acoustic Fruit ResponseResponse

Frequency DomainFrequency DomainTime DomainTime Domain

(b)-5

-3

-1

1

3

5

0 5 10 15 20 25TIME (ms)

AM

PL

ITU

DE

(V

)

Sensor-1

Sensor-2

Sensor-3

(d)0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 400 800 1200 1600FREQUENCY (Hz)

AM

PL

ITU

DE

(V

)

Sensor-1

Sensor-2

Sensor-3

Microphone Based Microphone Based System for Acoustic System for Acoustic

Firmness TestingFirmness Testinghp 35665A

Impact

Microphone Signal conditioner

Source: J. De BaerdemaekerSource: J. De Baerdemaeker

Comparison Between Comparison Between Two Acoustic Test Two Acoustic Test

MethodsMethods

35302520151055

10

15

20

25

30

35

FIRMNES INDEX - METHOD-A

FIR

MN

ES

S I

ND

EX

- B y = 0.00328 + 0.9954x

R^2 = 0.977

BRAEBURN

3025201510500

5

10

15

20

25

30

FIRMNESS INDEX - METHOD-AFI

RM

NE

SS

IN

DE

X -

B

y = -0.30995 + 1.0080x R^2 = 0.989

JONAGOLD

Method-A:Method-A: Microphone Microphone Method-B:Method-B: Piezoelectric-Film Sensor Piezoelectric-Film Sensor

Source: N. Galili & J. De BaerdemaekerSource: N. Galili & J. De Baerdemaeker

Acoustic Firmness Acoustic Firmness SensorSensor

A F SA F S TMTM

Source: AWETASource: AWETA

Method and Method and MaterialsMaterials• Mango (319) Tommy Atkins cultivar;Mango (319) Tommy Atkins cultivar;

• Shelf life conditions: 20 Shelf life conditions: 20 00C 50%RH;C 50%RH;

• 13 days, ( 12 experiments):13 days, ( 12 experiments): 25 fruits were tested daily both 25 fruits were tested daily both nondestructively nondestructively and destructively;and destructively;

• Three experiment set-up for input and Three experiment set-up for input and outputoutput signals measurements;signals measurements;

• Brix by digital refractometer, Atago's Palette 100.Brix by digital refractometer, Atago's Palette 100.

.

Quality Detection by Quality Detection by Impact ForceImpact Force

0 0.5 1 1.5 2 2.5 3 3.5 4

x 10-3

0

0.05

0.1

0.15

0.2

0.25

Time [sec]

Forc

e

[N]

day-1day-3day-5day-7

Correlation Between Correlation Between Firmness Index (FI) Firmness Index (FI)

and Sinclair (IQ)and Sinclair (IQ)y = 1.2575x + 6.8966R2 = 0.7385 n=319

0

10

20

30

40

50

0 5 10 15 20 25 30

Firmness by Firmalon [FI]

Fir

mn

ess

by

Sin

clai

r [I

Q]

Mango-Tommy

ResulResultsts

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14Time [day]

Fir

mn

es

s I

nd

ex

[10̂

4kg

2̂/3

S-̂2

] ( b )

ResulResultsts

10

15

20

25

30

35

40

45

0 2 4 6 8 10 12 14

Time [day]

IQ [

Firm

ness

Uni

t]

( a )

SummarySummary

The firmness indices from the two methods gave clear indications of the ripening process of mango fruit during shelf life.

The Sinclair firmness tester (IQ) correlated well to the acoustic and the destructive tests than the low-mass impact (LMI) by pendulum technique.

The good correlation between the firmness index, measured by an acoustic technique (FI) and the IQ firmness by Sinclair indicates that either of the two may successfully be implemented as an on-line sorter for mango fruit.

Current ResearchCurrent Research

IQ IQ TM TM Firmness Tester Firmness Tester

Sinclair International Sinclair International LTDLTD

NONDESTRUCTIVE NONDESTRUCTIVE

SENSOR SENSOR TECHNOLOGYTECHNOLOGY

NondestructiveNondestructive Firmness Firmness Measurement TechniquesMeasurement Techniques

Fruit Response to ForceFruit Response to Force Detection by Impact ForceDetection by Impact Force Forced VibrationsForced Vibrations Mechanical or Sonic ImpulseMechanical or Sonic Impulse Ultrasonic TechniquesUltrasonic Techniques Indirect Firmness MeasurementIndirect Firmness Measurement

NondestructiveNondestructive Firmness Firmness MeasurementMeasurement

Impact Force TechniqueImpact Force Technique

NondestructiveNondestructive Firmness Firmness MeasurementMeasurement

Acoustic TechniqueAcoustic Technique

Relationship between turgor Relationship between turgor pressure and tissue rigiditypressure and tissue rigidity

E=3.6 p +2.5 x10E=3.6 p +2.5 x1077 [ [ dynes/cmdynes/cm22]]

The Acoustic The Acoustic Parameters Parameters

of a Fruitof a Fruit Natural frequencies and firmness index - Natural frequencies and firmness index - FIFI

FI = f FI = f 22 m m 2/32/3 {10{104 4 kgkg2/32/3 s s-2-2} }

where: where: f f - first spherical resonant frequency - first spherical resonant frequency

mm - fruit’s mass. - fruit’s mass. Damping ratio - Damping ratio - The centeroid of the frequency response - The centeroid of the frequency response - ffcc

DestructiveDestructive Firmness Firmness

MeasurementMeasurement

ResultsResults

0 100 200 300 400 500 600 700 800 900 1000 1100

0

0.2

0.4

0.6

0.8

1

Frequency [Hz]

Norm

alize A

mplitu

de

day-1 day-3 day-5 day-7 day-9 day-12

0 100 200 300 400 500 600 700 800 900 1000 1100

0

0.2

0.4

0.6

0.8

1

Frequency [Hz]

Norm

alize A

mplitu

de

day-1 day-3 day-5 day-7 day-9 day-12

Parameters Parameters extracted from the extracted from the

measurementsmeasurements Low-Mass Impulse parameters: Low-Mass Impulse parameters:

C1 = Fp/Tp; C2 = Fp/Tp2 ; w (-20); and fc(in).

Acoustic parameters:

f1 ; FI ; and fc(out);

Destructive parameters: E ; Pene and Brix.

Quality Detection by Quality Detection by ImpactImpact

0 0.5 1 1.5 2 2.5 3 3.5 4

x 10-3

0

10

20

30

40

50

60

Time [sec]

F [N

]

day 1day 2day 3day 4

0 100 200 300 400 500 600 700 800 900

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Frequency [Hz]

Norm

alize

Am

plitu

de

day 1day 2day 3day 4

SummarySummary The new parameter of the input excitation signal in

frequency domain fc(in) can give a clear indication of firmness and ripening degree of mango fruit, independently of fruit size and shape.

Better correlations were achieved between the destructive indices and the input nondestructive parameter, as in compared to the output parameters. This can be explained by the fact that the output acoustic signal gives global indication of fruit properties and is sensitive to fruit shape, while the input signal represents local properties.

Summary (Cont. )Summary (Cont. )

The good correlation between the input and output parameters of the nondestructive tests indicates that integration of the two may improve the accuracy of the nondestructive dynamic tests for mango quality assessment.

Method and Method and MaterialsMaterials

Fruit Cultivar Amount Days

Nectarine Flamekiss 280 6

Avocado Fuerte 150 7

Melon Galia 160 11

Mango Tommy Atkins 309 12

Method and Method and MaterialsMaterials

• Shelf life conditions: 20 Shelf life conditions: 20 00C 50%RH;C 50%RH;

• Between 10 and 25 fruits were tested Between 10 and 25 fruits were tested daily both daily both nondestructively and destructively;nondestructively and destructively;

• Three experiment set-up for input and Three experiment set-up for input and outputoutput signals measurements;signals measurements;

• Destructive test;Destructive test;

• Brix by digital refractometer, Atago's Palette 100.Brix by digital refractometer, Atago's Palette 100.

.

ResulResultsts

10

15

20

25

30

35

40

45

0 2 4 6 8 10 12 14

Time [day]

IQ

[Fir

mn

ess

Un

it]

( a )

ResulResultsts

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14Time [day]

Fir

mn

es

s I

nd

ex

[10̂

4kg

2̂/3

S-̂2

] ( b )

Correlation Between Correlation Between Firmness Index (FI) Firmness Index (FI)

and Sinclair (IQ)and Sinclair (IQ)y = 1.2575x + 6.8966

R2 = 0.738 n=309

0

10

20

30

40

50

0 5 10 15 20 25 30

Firmness by Firmalon [FI]

Fir

mn

es

s b

y S

inc

lair

[IQ

]Mango-Tommy

Pearson linear correlation between the Pearson linear correlation between the nondestructive and destructive tests,nondestructive and destructive tests,

n=280 n=280 FlamekissFlamekiss-Nectarine,-Nectarine, Correlation is significant at the 0.05 level Correlation is significant at the 0.05 level

FI F1 SIQ TIQ E F

FI 1 0.976 0.787 0.881 0.873 0.875F1 1 0.773 0.874 0.878 0.865

SIQ 1 0.880 0.810 0.841TIQ 1 0.908 0.928

E 1 0.922F 1

Pearson linear correlation between the Pearson linear correlation between the nondestructive and destructive tests,nondestructive and destructive tests,

n=150 n=150 Fuerte-Fuerte-Avocado,Avocado, Correlation is significant at the 0.05 level Correlation is significant at the 0.05 level

FI F1 SIQ TIQ E MTCFI 1 0.977 0.714 0.721 0.689 0.695F1 1 0.737 0.747 0.702 0.710

SIQ 1 0.990 0.953 0.955TIQ 1 0.958 0.965

E 1 0.943MTC 1

Pearson linear correlation between the Pearson linear correlation between the nondestructive and destructive tests,nondestructive and destructive tests,

n=160 n=160 GaliaGalia-Melon,-Melon, Correlation is significant at the 0.05 level Correlation is significant at the 0.05 level

FI F1 SIQ TIQ E ECFI 1 0.960 0.750 0.761 0.892 0.669F1 1 0.683 0.731 0.821 0.613

SIQ 1 0.864 0.846 0.651TIQ 1 0.854 0.708

E 1 0.840EC 1

Pearson linear correlation between the Pearson linear correlation between the nondestructive and destructive tests,nondestructive and destructive tests,

n=309 Tommy Atkins-Mango,n=309 Tommy Atkins-Mango, Correlation is significant at the 0.05 level Correlation is significant at the 0.05 level

FI F1 SIQ TIQ E MTC

FI 1 0.955 0.859 0.742 0.716 0.487F1 1 0.801 0.714 0.648 0.440

SIQ 1 0.807 0.686 0.580TIQ 1 0.474 0.633

E 1 0.277MTC 1

Tommy Atkins-MangoTommy Atkins-Mango n=309 n=309

Thanks For Your Thanks For Your AttentionAttention

Thanks to the Thanks to the organizer organizer for a great for a great SymposiumSymposium

Pearson linear correlation between the Pearson linear correlation between the nondestructive and destructive tests,nondestructive and destructive tests,

n=205 n=205 TomatoTomato,, Correlation is significant at the 0.05 level Correlation is significant at the 0.05 level

FI F1 SIQ TIQ E F(x=2mm)

FI 1 0.949 0.710 0.763 0.560 0.614F1 1 0.701 0.731 0.523 0.590

SIQ 1 0.873 0.541 0.693TIQ 1 0.587 0.684

E 1 0.498F

(x=2mm)1