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Nondestructive Texture Assessment of Fruits and Vegetables

Nondestructive Texture Assessment of Fruits and Vegetables. by Itzhak Shmulevich Unlimited Postharvesting Leuven June 11-14, 2002. The Department of Agricultural Engineering. Technion-Israel Institute of Technology. Technion-Israel Institute of Technology.

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Nondestructive Texture Assessment of Fruits and Vegetables

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

  2. The Department of Agricultural Engineering Technion-Israel Institute of Technology

  3. Technion-Israel Institute of Technology The Department of Civil & Environmental Engineering, Agricultural Engineering Option

  4. Presentation outline • Introduction - firmness quality nondestructive measurements; • Impact technique vs. acoustic technique; • Experimental report on various fruits; • Results; • Discussion; • Conclusions.

  5. QUALITY ASSESSMENT

  6. Quality Factors of Agricultural Products • Appearance- visual • Texture - feel • Flavor - taste and smell • Safety • Nutritive Value

  7. Texture • Texture can be defined by subjective terms such as: Firmness Mealiness, Hardness, Softness, Brittleness, Ripeness, Toughness, Chewiness, Smoothness, Crispness, Oiliness, Springiness, Toughness, Fibrousness, or Juiciness etc.

  8. Quality Sensing in Commercial Settings Requirements • Nondestructive • External and internal properties • Accuracy • Speed (5-15 fruits/sec) • Recognize inherent product variability

  9. NONDESTRUCTIVE SENSOR TECHNOLOGY

  10. NondestructiveFirmness Measurement Techniques • Fruit Response to Force • Detection by Impact Force • Forced Vibrations • Mechanical or Sonic Impulse • Ultrasonic Techniques • Indirect Firmness Measurement

  11. Research Objective 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 q firmness using low compare sensing the fruit mass impulse excitation to the acoustic response For quality assessment of fruit and vegetable.

  12. Texture

  13. Relationship between turgor pressure and tissue rigidity E=3.6 p +2.5 x107 [ dynes/cm2] Modulus of Elasticity

  14. NondestructiveFirmness Measurement Impact Force Technique

  15. NondestructiveFirmness Measurement Acoustic Technique

  16. Method and Materials • Mango (210) Kent cultiver; • Shelf life conditions: 20 0C 50%RH; • 12 days, ( 10 experiments): • 80 fruit were tested daily only nondestructively • 130 fruit were tested both nondestructively and • destructively 12 fruit were tested daily; • Special experimental set up for input and output • signals measurements; • Brix by digital refractometer, Atago's Palette 100. • .

  17. Low-Mass Impact (LMI) Firmness

  18. IQ Firmness Sinclair International LTD IQ TM Firmness Tester

  19. DestructiveFirmness Measurement

  20. Destructive Tests

  21. Destructive Tests

  22. Force [N] Time [msec] Quality Detection by Impact Force

  23. Fp td d N Tp sec Quality Detection by Impact Force Chen. P (1996), Farabee (1991) Delwiche (1989 ,1991), Nahir et al. (1986 )

  24. The Acoustic Parameters of a Fruit • Natural frequencies and firmness index - FI FI = f 2m 2/3{104 kg2/3 s-2} where: f - first spherical resonant frequency m - fruit’s mass. • Damping ratio - z • The centeroid of the frequency response - fc

  25. Firmalon Prototype

  26. Firmalon

  27. Typical Acoustic Fruit Response Frequency Domain Time Domain

  28. Microphone Based System for Acoustic Firmness Testing Source: J. De Baerdemaeker

  29. Comparison Between Two Acoustic Test Methods Method-A: Microphone Method-B: Piezoelectric-Film Sensor Source: N. Galili & J. De Baerdemaeker

  30. Acoustic Firmness SensorA F STM Source: AWETA

  31. Method and Materials • Mango (319) Tommy Atkins cultivar; • Shelf life conditions: 20 0C 50%RH; • 13 days, ( 12 experiments): • 25 fruits were tested daily both nondestructively • and destructively; • Three experiment set-up for input and output • signals measurements; • Brix by digital refractometer, Atago's Palette 100. • .

  32. Quality Detection by Impact Force

  33. Correlation Between Firmness Index (FI) and Sinclair (IQ)

  34. Results

  35. Results

  36. Summary • 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.

  37. Current Research Sinclair International LTD IQ TM Firmness Tester

  38. NONDESTRUCTIVE SENSOR TECHNOLOGY

  39. NondestructiveFirmness Measurement Techniques • Fruit Response to Force • Detection by Impact Force • Forced Vibrations • Mechanical or Sonic Impulse • Ultrasonic Techniques • Indirect Firmness Measurement

  40. NondestructiveFirmness Measurement Impact Force Technique

  41. NondestructiveFirmness Measurement Acoustic Technique

  42. Relationship between turgor pressure and tissue rigidity E=3.6 p +2.5 x107 [ dynes/cm2]

  43. The Acoustic Parameters of a Fruit • Natural frequencies and firmness index - FI FI = f 2m 2/3{104 kg2/3 s-2} where: f - first spherical resonant frequency m - fruit’s mass. • Damping ratio - z • The centeroid of the frequency response - fc

  44. DestructiveFirmness Measurement

  45. Results

  46. Parameters extracted from the measurements 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.

  47. Quality Detection by Impact

  48. Summary • 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.

  49. 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.

  50. Method and Materials

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