phytosanitary irradiation: quality impacts on … irradiation: quality impacts on blueberries and...
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Phytosanitary irradiation: quality impacts on blueberries and cherries
ANURADHA PRAKASH
Study objectives
•Dose response studies to determine tolerance of fruit to phytosanitaryirradiation
•Determine the effects of distribution and retail conditions
•Compare irradiation to conventional treatments
2
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)
1. Dose response study
Blueberries treated with irradiation up to 800 Gy
Stored for 26 days
4
Sensory Evaluation
Nine panelists trained in 6 sessions to determine changes in quality attributes.
During evaluation they used 15cm unstructured scales 0-15 or none-to-intense.
Consumer testing with approx. 100 untrained consumers using 9 point
Hedonic scales
Analytical Measurement
Titratable Acidity, Brix
Texture: Firmtech & TA-XTPlus Texture
Analyzer
Color: Konica Minolta Spectrophotometer 2500d
Statistical Analysis
Linear fixed models and linear mixed models
(R statistical software)
Blueberry Trained panel
↓ Mouth Firmness
↓Touch Firmness
↓Flavor
800 Gy
↓Smoothness
↓Skin Firmness
Age
Analytical Analysis- Kramer Shear
0
100
200
300
400
0 0.4 0.6 0.8
Day 12
Day 26
Forc
e N
Dose (kGy)
There was a significant difference (p≤0.05) in texture between control and irradiated samples.
Blueberry Consumer Evaluation
6.466.85 a
6.42
5.82 b
1
2
3
4
5
6
7
8
9
Day 12 Day 26
Text
ure
6.526.82 a
6.39 6.25 b
1
2
3
4
5
6
7
8
9
Day 12 Day 26
0 kGy
0.8 kGy
Ove
rall
Lik
ing
Overall Flavor and Appearance Liking were
not affected by irradiation
Dose response study conclusionsBlueberries have a good tolerance to irradiation
Softening detected using instruments and trained panels
Consumer acceptance affected at doses >700 Gy
Weight loss, % decay, color, bloom not affected by irradiation
8
Combination with MAPIrradiation is an effective phytosanitarytreatment
MAP has been shown to retain blueberry quality◦ Slower rates of ripening◦ Growth of aerobic spoilage microorganisms and oxygen-
dependent pests inhibited◦ Limits moisture loss◦ Longer product shelf-life
Combination treatment?
2. The effects of modified atmosphere packaging and irradiation on the quality of blueberries under simulated commercial transportation and retail conditions
Star varJune 2012
Jewel varJuly 2012
Snowchaser varSeptember 2012
Harvest
Control Irr MAP IMAP
Arrive at Chapman – Preship Test
4-7 days
Air Shipment Simulation @ 4 °C (1 day)
Storage (3 day) @ 20°C
Quality Assessment
Ground Shipment Simulation @ 4 °C (8 day)
Storage (3 day) @ 20°C
Quality AssessmentSea Shipment Simulation @ 4 °C
(21 day)
Storage (3 day) @ 20°C
Quality Assessment
Postharvest Treatments
MAP applied about ~18 hrs before irradiationTarget dose: 0.4 kGyReceived up to 0.8 kGy
Effect of distribution and retail conditions
Different varieties/seasons of the same fruit can exhibit varied responses to irradiation
Blueberry firmness
Decay
Sea
Ground
Control IRR MAP IMAP
Effect of modified atmosphere packaging
Weight
Jewel variety - Sensory
Overall Liking Texture Appearance Flavor
Treatment
Air Simulation
Ground Simulation
Sea Simulation
Air Simulation
Ground Simulation
Sea Simulation
Air Simulation
Ground Simulation
Sea Simulation
Air Simulation
Ground Simulation
Sea Simulation
Jewel
Control 6.7±0.2ax 6.1±0.1ay 4.8±0.2cz 6.8±0.2ax 6.3±0.1by 5.2±0.2bz 7.4±0.1ax 7.0±0.1ay 6.3±0.2bz 6.7±0.2ax 6.2±0.1ay 5.1±0.2bz
IRR 6.8±0.3ax 6.5±0.3ay 5.8±0.6bz 6.9±0.2ax 6.5±0.3aby 5.8±0.5bz 7.4±0.2ax 7.1±0.3ay 6.4±0.5bz 6.8±0.3ax 6.5±0.3ax 6.0±0.6ax
MAP 6.4±0.3ax 6.4±0.3ax 6.6±0.6ax 6.7±0.2ax 6.7±0.3ax 6.7±0.5ax 7.0±0.2ax 7.1±0.3ax 7.3±0.5ax 6.4±0.3ax 6.4±0.3ax 6.6±0.6ax
IMAP 6.6±0.3ax 6.5±0.3ax 6.4±0.6ax 6.5±0.2ax 6.5±0.3abx 6.6±0.5ax 7.1±0.2ax 7.1±0.3ax 7.2±0.5ax 6.7±0.3ax 6.5±0.3ax 6.2±0.6ax
Texture Appropriateness (JAR Scale)Treatment
Air Simulation
Ground Simulation
Sea Simulation
JewelControl 2.7±0.1ax 2.4±0.0by 2.0±0.1bzIRR 2.7±0.1ax 2.6±0.1aby 2.3±0.2bzMAP 2.8±0.1ax 2.7±0.1ax 2.6±0.2axIMAP 2.5±0.1ax 2.6±0.1abx 2.7±0.2ax
Significant decreases in Control and IRR over time
Maintenance of higher scores over time in MAP and IMAP
3. 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
4 d
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)
Firmness-Kramer Shear
Damage and Physical Defects
Yeast and mold
Control Irr MB MAP IMAP MBMAP
Treatments
Day
11
38
53
Consumer-Overall Liking
Salmonella survival in blueberries
0.00
1.00
2.00
3.00
4.00
5.00
6.00
0 7 14 21 28
Log
Val
ue
of
CFU
/g
Days
Control Irradiated
Sweet Cherries
❖ Sweetheart: July and August, 2013, Washington
❖ 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
Bag in the box, LDPE (Freshlok, Yakima, WA)
Firmness-Kramer Shear
Sensory-appearance
Damage
Consumer-Overall liking
Control Irradiation
MB
MAP
IMAP MBMAP
Trial 2, Day 27
Sweet Cherries-conclusions◦Shelf life of 4-5 weeks before showing significant signs of quality loss
◦Harvest season is a significant factor
Overall Results
• Irradiation preserves quality better than MeBr• MAP helps maintain quality• Cannot easily generalize responses of all fruit• Varietal and maturity differences
Quality is highly dependent on:Initial qualityGas concentrations Temperature
Harvest date
Next steps•Optimize MAP
•Evaluate influence of harvest date during the season
•Assess intra-year variations
•Conduct commercial sea and air shipment tests of irradiated fruit
Acknowledgments
Jonathan TongKaren ThangKimberlee AuSheila LeeVikalp Joisar
USDA-APHISU.S. Highbush Blueberry CouncilSadexNutek CorporationApio IncVeg-Fresh FarmsSodexo
Consumer Acceptance
•Consumers respond positively when informed
•People buy irradiated food
•Insect quarantine applications with produce are expected to grow
•Focus on the product and its benefits, rather than the technology
•Most (but not all) will buy when given the opportunity