Postharvest Quality and Physiology of ‘Fuji’ Apples ...
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Spring 5-10-2017
Postharvest Quality and Physiology of ‘Fuji’ ApplesSubjected to Phytosanitary IrradiationNasim KheshtiChapman University, [email protected]
Alan BaqueroChapman University, [email protected]
Anderson MeloChapman University, [email protected]
Anuradha PrakashChapman University, [email protected]
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Recommended CitationKheshti, Nasim; Baquero, Alan; Melo, Anderson; and Prakash, Anuradha, "Postharvest Quality and Physiology of ‘Fuji’ ApplesSubjected to Phytosanitary Irradiation" (2017). Student Research Day Abstracts and Posters. 232.http://digitalcommons.chapman.edu/cusrd_abstracts/232
Postharvest Quality and Physiology of ‘Fuji’ Apples subjected to
phytosanitary Irradiation
Kheshti, N., Baquero, A., Melo, A., Prakash, A.
Introduction
In the state of California, apples are harvested almost
a month before Washington’s apple harvest, therefore,
California has a time advantage in exporting apples
overseas. However, quarantine restrictions require
that California apples either be fumigated with methyl
bromide or be kept at 0˚C for 40 days or at 3.3 ˚C for
90 days to prevent spread of of Light Brown Apple
Moth and Oriental fruit moth (1, 2). Both treatments
have some disadvantages. Methyl bromide is ozone
depleting and with cold treatment, California loses its
time advantage in comparison to Washington state.
Irradiation is an effective treatment to sterilize and
destroy insect pests on apples and was recently
approved for apples exported to Mexico from
California (3). However, the impact on quality and
shelf of the apples is not known.
ObjectiveTo investigate the influence of the irradiation on
physicochemical properties of Fuji apples after
harvest and compare the quality of irradiated apples
with those treated with cold storage and fumigation.
The specific goals are to:
1. Determine the tolerance of apples to irradiation at
400 and 800 Gy.
2. Conduct a comparative evaluation of irradiated,
fumigated, and cold treated apples
Experimental Method
Results and Discussion Results and Discussion (cont.)
Irradiation caused an immediate decrease in
firmness by 12% at 400 Gy and by 38% at 800 Gy; this
difference remained throughout storage.
Electrolyte leakage was higher (P<0.05) in the 800
Gy apples as compared to control and 400 Gy.
Irradiation initially elevated respiration rate by 27%
at 800 Gy and 15% at 400 Gy. During storage at cold
temperature there was no significant difference between
control and 400 Gy while 800 Gy continued to be
significantly higher.
Ethylene decreased by 29% at 800 Gy and 18% at
400 Gy one day after treatment. During storage at room
temperature, ethylene levels increased significantly in the
control and 400 Gy, and remained constant and
significantly lower at 800 Gy.
ConclusionsThe increase in respiration rate was not reflected in most
of the quality parameters measured. The impact on
firmness and electrolyte leakage on quality perception
needs to be corroborated with sensory tests.
Future Study
Further studies on impact of irradiation on enzyme
activities such as PAL and PME would be helpful to
understand the basis of changes in respiration rate and
firmness. It would also be beneficial to study the effect of
maturity stage on irradiated fruit quality.
Acknowledgements
I would like to thank Dr. Anuradha Prakash for her
continued support and patience in guiding us through
this project and USDA-FAS for funding this project, Prima
Fruitta for providing the apples and Steri-tek for radiation
treatment. We are grateful to Todd Sanders of the
California Apple Commission for his technical assistance.
References
1. Lynch B. 2010b. Apples Industry and trade summary.
Washington: Office of Industries.
2. USDA. 2016. Treatment Manual. Non-Chemical
Treatment.
3. Phytosanitary Export Database. 2016 Available from:
https://pcit.aphis.usda.gov/PExD/faces/ViewPExD.jsp.
Apples sourced from a single farm were obtained from adistributor and shipped to a electron beam irradiationfacility where they were irradiated at 0, 400, 800 Gy.
Apples kept 7 days in cold temperature for simulating therefrigerated transportation of the apples from California toMexico. Then, the apples were placed in ambienttemperature for 7 days in order to simulate the retailcondition.
Statistical Analysis :
Linear fixed models and linear mixed models (R statistical software)
Figure 3. Firmness of the apples during storage- Irradiation
decrease firmness.
Figure 7. Peroxidase enzyme activity during storage time
Figure 4. Electrolyte Leakage of the apples during
storage. Irradiation increase EL.
Irradiation:
Freshly harvested apples, washed, waxed,
boxed, cooled
Refrigerated transport to Chapman University
Refrigerated transport to irradiation facility
Control 250 Gy
Baseline analysis upon arrival at CU
Analysis with fresh tissue
Respiration rate/Ethylene (every two days)
Starch iodine test
Color (sensory/instrumental)
Texture (Firmness)
Electrolyte Leakage
Quality indices (TSS/TA)
Damage, decay
1 week at ambient temperature
Analysis with frozen tissue (-80 ºC) Irradiated fruit only
Malondialdehyde (MDA)
Total phenolics
Organic Acids
Sugars
Cell wall degrading enzyme (PME)
Cold treated: Washed, waxed, cooled, O-1
C storage for 40 daysMeBr: Freshly harvested apples
washed, waxed, boxed, fumigated,
cooled
Refrigerated for 1 week
1000 Gy
Shikimic acid in treated apples during storage
Ctrl 400 Gy 800 Gy Ctrl 400 Gy 800 Gy Ctrl 400 Gy 800 Gy
Shik
imic
(µg/
g F
W)
0
1
2
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One Day After Treatment
Day 7
Day 14
a b b a ab ba aa
POD Enzyme Activity During Storage Time
Ctrl 400 Gy800 Gy Ctrl 400 Gy800 GyCold trt Ctrl 400Gy800 GyCold trt
POD(
A/m
in)
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400 Gy
800 Gy
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400 Gy
800 Gy
Cold trt
One day after treatmentt
Day 7
Day 14
aab a
a a a aab b a
b
Figure 1. Respiration rate of the apples during storage.
Irradiation increase respiration rate.
Figure 5. Internal view of different treated apples. No
difference in browningFigure 6. Browning index of different treated apples
during storage time. No significance difference
400
800
Figure 8. Shikimic acid during storage time.
Chemical Analysis
Ctrl
400GY
800Gy
Ele
ctr
oly
te L
eak
ag
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0 7 14
Storage Time (Day)
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800Gy
0 2 4 7 9 11 14
Storage Time (Day)
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400GY
800Gy
Storage Time (Day)
0 2 4 7 9 11 14
a
bc
a
b
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Figure 2. Ethylene production rate during sorage-
Iradiation decrease ethylene production rate.