Trade

1. Effect of Irradiation on Fruit
Quality
Anuradha Prakash
Chapman University

2. Outline
• Quality considerations
• Effects of phytosanitary
irradiation on fruit
• Research on blueberries
• Cherries to Vietnam

3. Phytosanitary Irradiation of Fruit
• Cold treatment
• Phytosanitary doses are low!
• Quality dependent on
• Extrinsic factors:
• Dose
• Temperature
• Atmosphere/Packaging
• Handling
• Intrinsic factors:
• Variety and cultivar
• Maturity stage
• Climacteric versus non-climacteric
• Composition

4. Most fruit can be irradiated between 150-
600 Gy with no adverse effects on quality
Sugraone Crimson Red

5. Foods 2015, 4, 376-390; doi:10.3390/foods4030376

6. Courtesy Marissa Wall, 2012,
USDA ARS, Hawaii

8. Ethylene and Ripening

9. Courtesy Marissa Wall, 2012
USDA-ARS, Hilo, Hawaii

10. Irradiation- an abiotic stress

11. Effect of irradiation on climacteric fruit
Delay in ripening
• Banana
• Papaya
• Mango
• Pear
• Treatment of immature fruit- greater
delay of ripening
• Treatment of mature fruit- better
quality
• Temperature of storage is very
important
Acceleration of ripening
• Peaches
• Nectarines

12. - Increased respiration rate
J Sci Food Agric 80

13. Control 0.8 kGy
- Delayed ripening

14. http://biology-forums.com/gallery/18099_27_04_12_6_29_54.jpeg
-Acceleration of ripening
-Softening

15. - Phenolic biosynthesis
http://www.mdpi.com/2077-0472/2/3/259/htm

16. Day 1 after
irradiation
4 weeks
3 weeks
Control 150 Gy 1000 Gy
Chandler pummelos

17. Differences among varieties
Dr. Edmundo Mercado Silva

18. Post harvest decay
• Inhibition of fungal rot requires doses >1.5 kGy
• At these dose levels, most fruit show negative impacts on quality
• Softness
• Undesirable flavors
• Altered metabolism and ripening
• Combination treatments may help
• Hot water dips
• Fungicides
• Controlled/modified atmospheres

19. TASC Grant
Quality Study objectives
• Dose response studies to determine tolerance of fruit to
phytosanitary irradiation
• Determine the effects of distribution and retail conditions
• Compare irradiation to conventional treatments
19

20. Comparing irradiation and methyl bromide fumigation
in combination with MAP
Harvest
Chapman University
MeBr FumigationIrradiation
Control Irradiation MAP MB IMAP MBMAP
Analytical and Sensory Testing Weekly
Statistical Analysis

21. Blueberries
• Climacteric fruit
• Average Shelf-life: 2 weeks
• Optimum Conditions:
• Temperature: 31-32°F
• Relative Humidity: 90-95%
• Controlled Atmosphere: 10-15% CO2 and 1-10% O2
• Top-quality Blueberries:
• Free from damage & physical defects
• Free from mold growth (Botrytis and Rhizopus rot)

22. Treatment conditions
❖ Bluecrop: July and August, CA
❖ Fumigation: Global Pest Management (Long
Beach, CA)
➢ 21.1°C
➢ 2 h at 32 g/m3
➢ Degas for 4-5 h
❖ Gamma Irradiation: Sterigenics (Tustin, CA)
➢ Target dose: 400 Gy
 MAP
 BreatheWay® Membrane MAP bags, (Apio, Inc., Guadalupe,
CA)

23. Firmness-Kramer Shear

24. Damage and Physical Defects

25. Control Irr MB MAP IMAP MBMAP
Treatments
Day
11
38
53

26. Consumer-Overall
Liking

27. Sweet cherries to Vietnam
Air freighted to
Ho Chi Minh City
Unwrapped, ambient
temperature retail
display
Quality evaluation
MeBr
15.56 °C and
32g/m3 for
3.5 hours
Forced air
cooled to
1°C
Irradiation
Forced air
cooled to
1°C
Gamma
400 Gy
Control Maintained
cold
Freshly harvested
Washington sweet
cherries, trucked to
Los Angeles

28. 0
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Transportation Day 1 Day 2 Day 3 Day 4 Day 5
Temperature(°F)
Control Ambient MeBr Ambient IRR Ambient

29. Grading
0
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0 1 3 5
Control MB IR
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14 15 17 19
Days

30. % Decay
0
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100
14 15 17 19Days
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0 1 3 5
Control MB IR

31. Control 400 Gy Fumigated

32. Overall Results
• Cannot easily generalize
responses of all fruit
• MAP helps maintain quality
• Irradiation preserves quality
better than MeBr
• Shelf-life may or may not be
better than non-treated fruit

33. Considerations for trade
of irradiated produce
• Fruit varieties
• Initial quality
• Maturity at harvest
• Handling
• How is the fruit packed?
• Where is the product
exported to?
• How long does it take?
• Shipping, distribution
and retail conditions

34. Challenges to use of
phytosanitary irradiation
• Maintaining cold chain – true for any
treatment
• Conventional treatments still in use
• Location of irradiation facilities
• Added cost
• Regulatory hurdles
• Willingness of retail outlets to carry irradiated
fruit

35. Gracias!
Anuradha Prakash
Professor and Program Director
Chapman University
(714) 744-7826
prakash@chapman.edu