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Kentaro InoueUniversity of California, Davis
[email protected] 15th, 2010
Fruit ripeningColor change and Conditioning
1. Fruit development – Definition of maturation and ripening
2. Importance of color
3. Conditioning for ripening- Some climacteric fruits as examples
Fruit ripeningColor change and Conditioning
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Stages of fruit development1. Fruit development
MaturationThe stage of development leading to the attainment
of physiological or horticultural maturity
• Physiological maturity:– The stage of development when a plant or plant
part will continue ontogeny even if detached
• Horticultural maturity:– The stage of development when a plant or plant
part possesses the prerequisites for utilization by consumers for a particular purpose
1. Fruit development
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Ripening:The composite of the processes:- Occurring from the latter stages of growth
and development through the early stages of senescence
- Resulting in characteristic aesthetic and/or food quality, as evidenced by changes in composition, color, texture, orother sensory attributes
1. Fruit development
Compositional changes accompanying fruit ripening1. Fruit development
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Maturity and ripeness stages of Maturity and ripeness stages of cherry tomatoescherry tomatoes
1 2 3 4 5 6 >6 1 2 3 4 5 6 >6
Optimal harvest stages 1. Fruit development
For us..
For plants..
- Cosmetic value- Indicator of ripening
- Nutritional value
- Red/orange etc - Attract seed dispersers- Protect tissues from oxidative stress
= Antioxidant
- Green - light capture (photosynthesis)
Importance of “Color”
2. Importance of color
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http://www.recipezaar.com/bb/viewtopic.zsp?t=254626
Anthocyanins
antioxidants
O+
O-Glc
OH
OH
OH
OH
OCH3
O
O
O
O
R1
O
R2
O
provitamin A
antioxidants
2. Importance of color
Carotenoids
Vacuole
chromoplasts
nucleusmitochondria
O+
O-Glc
OH
OH
OH
OH
OCH3O
O
O
O
R1
O
R2
O
“Phenylpropanoids*” “Isoprenoids (terpenoids*)”
cell
Plasma membraneCell wall
*Cf. Dr. Zakharov’s lecture 2. Importance of color
Anthocyanins Carotenoids
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O
O
O
O
R1
O
R2
O
http://www.hormel.com/images/glossary/m/mango_champagne.jpg
chromoplast
lycopene
cis-β-carotene
Esters of cis-violaxanthin
“crystaline structure”
“globules”
Electron microgram
2. Importance of color
N
N
N
CH3O OH O
HH
Mg2+
N
R1
OO
R2
carotenoids“Non-photosynthetic”
chromoplast
chloroplast
“Photosynthetic”carotenoids
chlorophylls
OH
OH
O
O
O
O
R1
O
R2
O
Color Break
2. Importance of color
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Thylakoidstacking
Carotenoid-containing globules
Electron microgram by Thomson ‘66
2. Importance of color
Group 1: Nonclimacteric fruits:Fruits that are not capable of continuing their ripening process once removed from the plant
WatermelonPineappleLongan
TamarilloPepper (bell)Lime
StrawberryOrangeLemon
RaspberryMuskmelon*Grapefruit
RambutanMandarinGrape
Prickly pearLycheeCherry
PomegranateLoquatBlackberry
*Some muskmelon varieties are climacteric, but are best when harvested partially- or fully-ripe.
3. Conditioning for ripening
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Maturity and ripeness stages of cherries
Optimal harvest stage
3. Conditioning for ripening
Strawberries must be picked fully-ripe
b/c they do not continue to ripen (improve in flavor) after harvest
Maturity and ripeness stages of strawberries
Optimal harvest stage
3. Conditioning for ripening
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Group 2: Climacteric Fruits:Fruits that can be harvested at physiological maturityand ripened off the plant
Pepper (chili)Kiwifruit
TomatoPearGuava
SapotePeachCherimoya
SapodillaPassion fruitBanana
QuincePapayaAvocado
PlumNectarineApricot
PersimmonMangoApple
Except avocado, banana, and pear, these fruits attain best flavor if ripened on the plant
3. Conditioning for ripening
Maturity and ripeness stages of apricots
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22
33 55
44 Optimal harvest stages for good flavor
3. Conditioning for ripening
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Optimal conditions for ripening of climacteric fruits
Ripening roomsTemperature: 15 to 25ºC (59 to 77ºF)Relative humidity: 85-95%
Air circulation (more uniform temperature and ethylene concentration)
Ventilation (introduction of fresh air to keep carbon dioxide below 1%)
Treatment with ethylene100 ppm ethylene in air for 1-3 days, depending on maturity stage at harvest
3. Conditioning for ripening
Ripening rooms
Temperature and relative humidity management is the most important factor affecting ripening rate & uniformity
3. Conditioning for ripening
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Ripening rooms
Ethylene generator
Forced-air (pressure) ripening room
3. Conditioning for ripening
18-20ºC / 65-68ºF24-72Tomato
20-25ºC / 68-77ºF24-48Pear
20-25ºC / 68-77ºF24-48Mango
12-25ºC / 54-77ºF12-24Kiwifruit
14-18ºC / 58-65ºF24-48Banana
15-20ºC / 59-68ºF8-48Avocado
Range of ripening temperatures2
Exposure time (hours)1
to 100ppm ethylene Fruit
1 Shorter duration for more mature fruit2 Faster ripening rate at higher temperatures
Ripening conditions for some commonly-ripened fruit
3. Conditioning for ripening
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Current recommendations for avocado ripening
Adequate air flow to keep CO2 below 1%
Carbon dioxide level:
8-48 hr, depending on maturity stage
Duration:
10-100ppmEthylene concentration:
90-95%Relative humidity:
15.5-20°C (60-68°F)Temperature:
3. Conditioning for ripening
Effect of harvest date (maturity) on the time to ripen for ‘Hass’ avocado
5.18.2June 5
7.110.1April 10
8.812.8Feb. 6
10.813.9Dec. 8
Treated*ControlHarvest date
Days to ripen at 20°C (68°F)
* Fruit treated with 1000ppm propylene, an ethylene analogue
3. Conditioning for ripening
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Ethylene (C2H4) is required to induce banana ripening
3. Conditioning for ripening
Ethylene (C2H4) induces ripening of various banana and plantain cultivars
3. Conditioning for ripening
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Ripening conditions for banana
Adequate air exchange to prevent accumulation of CO2 above 1%
Carbon dioxide:
24-48 hours, depending on maturity stage
Duration of
exposure to ethylene:
100 ppmEthylene concentration:
90-95%Relative humidity:
14-18°C (58-65°F)Fruit temperature:
3. Conditioning for ripening
Effect of temperature during ripening on banana quality attributes
3. Conditioning for ripening
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=
3. Conditioning for ripening
Note the 5-fold increase in respiration rate (carbon dioxide production) as banana ripens from stage 2 to stage 4.
mg
kg
3. Conditioning for ripening
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Carbon dioxide reduces efficacy of ethylene in inducing banana fruit ripening
3. Conditioning for ripening
80% RH
Low relative humidity (RH) accelerates water loss and appearance of physical damage symptoms on banana
3. Conditioning for ripening
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Mango maturity indices• Fruit shape (fullness of the shoulders)
• Skin ground color change from dark-green to light-green to yellow (depending on cultivar)
• Flesh color change from green to yellow to orange
• Increase in total solids (dry weight)
• Increase in soluble solids (mainly sugars) and decrease in acidity
3. Conditioning for ripening
Mango maturity and ripeness stages
*
**
*
*Minimum stage for harvestManilla
Kent
3. Conditioning for ripening
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Ripening conditions for mango
<1%Carbon dioxide:
24-48 hours, depending on maturity stage (flesh firmness)
Duration of
exposure to ethylene:
100 ppmEthylene concentration:
90-95%Relative humidity:
20 to 22°C (68-72°F)Fruit temperature:
3. Conditioning for ripening
3. Conditioning for ripening
Mango ripeness vs. flesh firmness
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1
2
3
4
Maturity and ripeness stages of Nectarine
Immature
Mature-green
Partially-ripe
Ripe
1
2
3
4
3. Conditioning for ripening
Ethylene effects on stone fruit ripening at 20°C (68°F) as indicated by flesh firmness (means + standard deviation)
1.8±1.02.2±0.61.8±0.4With 20ppm ethylene
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3.7±2.12.8±1.22.3±1.0W/O added ethylene
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6.1±1.915.3±1.511.6±2.1At harvest0
PlumPeachNectarineTreatmentDays
Flesh Firmness (pounds-force)
3. Conditioning for ripening
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Delayed cooling = conditioning = ripening of peaches to reduce internal breakdown
0ºC 20 Days 20ºC 48 Hours + 5ºC 20 DaysFrom: Carlos Crisosto
(43% Mealy) (0% Mealy)
(100% Mealy)
5ºC 20 Days
3. Conditioning for ripening
SmartfreshTM TechnologyOn July 17, 2002, USEPA approved registration of SmartfreshTM
technology and established an exemption from tolerance for its active
ingredient: 1-methylcyclopropene (1-MCP) for the following fruits:
apple, apricot, avocado, kiwifruit, mango, melon, nectarine, papaya, peach, pear, persimmon, plum, tomato.
Approval in other countries and for more commodities has occurred since 2002.
Responses of 1-MCP-treated fruits to ethylene depends on 1-
MCP concentration used (100 to 1000 ppb) and elapsed time
since the treatment.
3. Conditioning for ripening
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