Optimum procedures for ripening tomatoes

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Fruit Ripening & Ethylene Management Page 98
Optimum Procedures for Ripening Tomatoes
by Marita Cantwell
Tomato Quality
The most important quality criteria for tomatoes are
red color, firm but juicy texture, and good flavor.
Good flavor depends principally on the amount of
sugars, acids and aroma volatiles. Different types of
tomatoes vary greatly in the content of sugars, acids
and other constituents (Table 1). Tomatoes with high
sugar and relatively high acid contents are the best
flavored, while low sugars and low acids result in
poor flavored tomatoes. The development of the
“jelly” in the locules of the fruit is important for good
tomato flavor since this locular tissue contains rela-
tively high concentrations of the sugars and acids.
Maturity and Ripeness Stages
Tomatoes may be harvested at various stages of ma-
turity and ripeness (Table 2). Tomatoes harvested
without any external red color are called mature-
green tomatoes, while those harvested at breaker or
more advanced stages are called vine-ripe tomatoes.
Since vine-ripe tomatoes may be less firm than ma-
ture-green fruit, extra care must be taken in their han-
dling to reduce bruising, compression and other
physical injuries. Table 3 describes typical color
changes for round tomatoes at different stages of ripe-
ness. Cultivars of round tomatoes for field produc-
tion can be harvested at mature-green stage and be
ripened into good quality tomatoes. However if fruit
are harvested without sufficient internal development
and are poorly handled, final ripe fruit quality will be
poor. For small tomatoes, harvesting at early color
stages (3) significantly reduces the sugar and soluble
solids contents in ripe fruit (Table 4).
Importance of Temperature on Ripening of Vine-
ripe fruits
For tomatoes with external color (vine-ripes), manag-
ing temperature will control the rate of ripening
(Table 5). Fruit with external color are already gener-
ating sufficient ethylene to complete the ripening
process. Temperatures that are both too low and too
high have serious consequences to tomato fruit qual-
ity. Superior quality tomatoes result if the fruits are
ripened at temperatures of 15-20°C (59-68°F). Rip-
ening fruits at temperatures above 25°C (77°F) results
in soft, poorly-colored fruits as high temperatures
inhibit ethylene production which is needed for good
lycopene synthesis (Figure 1). Breaker stage fruits
stored and ripened at temperatures of 15- 20°C (59-
68°F) have longer shelf-life, greater overall visual
quality, are firmer with less weight loss, have more
red color, and less decay than fruits ripened at higher
temperatures. Once fruits reach the red stage, an addi-
tional week of shelf life (with little change in firm-
Figure 1. The effect of temperature on the ripening physiol-
ogy of conventional round tomato (cv Mt. Fresh) fruit
(Cantwell, unpublished).
Respiration µL CO
2
.g
-1
h
-1
0
5
10
15
20
25
30
35
40
A. Respiration
Ethylene production nL.g
-1
h
-1
0
1
2
3
4
5
6
7
Days from Breaker Stage
-20246810
Color Score (1=green, 6=table-ripe)
1
2
3
4
5
6
B. Ethylene production
C. Color change
Mature-green Fruit
12.5°C (55°F)
20°C (68°F)
30°C (86°F)
Cantwell, M. 2010. Optimum Procedures for Ripening Tomatoes. In: Fruit Ripening and Ethylene Management, J.T. Thompson and C. Crisosto (eds.), UC
Postharvest Horticulture Series 9:106-116. http://postharvest.ucdavis.edu/files/93536.pdf.
Fruit Ripening & Ethylene Management Page 99
ness or flavor) can be expected if the fruits are held at
15-20°C (59-68°F) and are not physically damaged.
Unfortunately tomatoes are often stored at tempera-
tures below recommended and then ripened at tem-
peratures above optimum (Figure 2). This simply
leads to fruit with poor color and flavor.
Tomatoes are chilling sensitive and should not be
stored below 10°C (50°F) (Figure 2). Symptoms of
chilling injury on tomatoes may include decreased
flavor, lack of uniform ripening, and softness and
mealiness when transferred to warmer temperatures
for ripening. If tomatoes are stored long enough at
low temperature, there will be increased decay. Black
Alternaria decay on the stem end and shoulders is a
typical symptom of severe chilling injury. When
fruits are stored below the recommended 10°C (50°
F), volatile compounds that impart typical tomato
aroma and flavor are substantially reduced. This oc-
curs long before any visual symptoms of chilling oc-
cur. For example 4 days at 5°C (41°F) cause a signifi-
cant reduction in flavor quality, but about 6-8 days at
5°C (41°F) were neede to cause decay. Figure 3 il-
lustrates the impact of lower than recommended stor-
age temperature on the final red color and lycopene
content of round tomatoes. Storing tomatoes at 5°C
(41°F) for 1 week decreased the capacity of the fruit
to develop full red color when transferred to 20°C
(68°F) to complete ripening. Storage at 7.5°C (45°F)
for 2 weeks had a similar effect. The best option to
ensure final red color development is to store the fruit
not lower than the recommended temperature of 10°C
(50°F).
Ripening Mature-Green Fruit
Tomatoes with external color do not benefit from eth-
ylene treatment. Fruits with external color (stage 3)
are producing their own ethylene which is sufficient
to complete the ripening process. Mature-green fruits
also produce low amounts of ethylene and may even-
tually ripen. Generally though, mature-green fruit are
ethylene-treated to accelerate the ripening process.
Fruits respond better if ethylene treated soon after
harvest rather than after storage. It is generally rec-
ommended to use 100 ppm ethylene at 18-20°C (64-
68°F) with high humidity (>90%). Sufficient air flow
(about 0.1 to 0.2 cubic feet per minute per pound) to
maintain a uniform temperature profile through the
°F °C
32 0
35 2
40 4
45 7
50 10
55 12
60 16
65 18
70 21
75 24
80 27
85 29
90 32
Ripening
Range
MAX.
MIN. Recommended transit
& storage temperatures
Not more than
1-2 days
Recommended
Ripening Temp.
TOO COLD
Chilling injury
Poor color, flavor
Poor ripening,
softening
TOO WARM
Freezing point
31°F, -0.5°C
Figure 2. Tomatoes are chilling sensitive and
should not be stored below 10°C(50°F)
Hue color value
40
42
44
46
48
50
52
LSD.05
Weeks storage
0123
Lycopene, mg/kg FW
35
40
45
50
55
60
Red color, Hue
Lycopene
LSD.05
12.5°C (55°F)
10°C (50°F)
7.5°C (45°F)
5°C (41°F)
12.5°C (55°F)
10°C (50°F)
7.5°C (45°F)
5°C (41°F)
Figure 3. Red color values and lycopene concentra-
tions of tomatoes that were stored at 4 temperatures
and then ripened at 20°C (68°F). Fruit were color
stage 3 (30% color) when stored. The lower the hue
color value, the redder the fruit (Ara and Cantwell,
unpublished).
Fruit Ripening & Ethylene Management Page 100
room is important to ensure uniform ripening. Suffi-
cient ventilation is required to keep CO2 levels low
(<2%) or ripening will be slowed.
Tomatoes should respond within 3-3.5 days to ethyl-
ene treatment and reach breaker-turning stages of ripe-
ness. Fruits not showing external color change by that
time indicate fruits which were immature at harvest
and which should be discarded. Once ethylene has ini-
tiated ripening and external color change, the rate of
ripening can be managed at a range of temperatures as
shown in Table 4.
Poor flavor in tomatoes harvested as mature-green
fruit and ripened may be due to:
• harvesting immature fruit rather than well developed
mature-green fruit
• long delays from harvest to final ripening
• storing at lower than recommended temperatures and
then ripening
• mechanical damage which can lead to off-flavors.
Lack of uniform color in a tomato box
“Checkering-boarding” or lack of uniform coloration
is still a problem with mature-green ethylene treated
fruit and a high percentage of fruits require repacking.
Although this problem should not occur with vine-ripe
greenhouse tomatoes, it can happen if the packers are
not well trained or do not have sufficient time to dis-
tinguish between tomatoes with small differences in
external color. These small differences at the time of
packing will lead to greater heterogeneity during the
shipping and marketing period. Greenhouse fruit
should have a minimum of 20 or 30% external color to
ensure ripening uniformity in the box and to avoid
costly repacking.
Ripening Long Shelf-life Varieties
There are many varieties and experimental tomato
lines called long shelf-life (LSL) or extended shelf-life
(ESL) varieties which contain ripening mutant genes.
Figure 4 illustrates the effects of the rin mutant on
tomato ripening physiology. If these varieties are har-
vested too early in color development, they may not be
able to attain a final full red color. Lycopene synthesis
in tomatoes is linked to ethylene production capacity.
In such cultivars, harvesting fruit with more color en-
sures they are able to complete postharvest color de-
velopment. This is the case of many varieties grown
for greenhouse production and they need to be har-
vested with 30% or more color development. The rip-
ening physiology of both so called ‘conventional’ and
‘long-shelf life’ tomato cultivars may vary substan-
tially (Table 6).
Tomato ripening and 1-MCP (SmartFresh®)
SmartFresh® or 1–MCP is a very potent inhibitor of
ethylene action in fruits and can be used to manage
fruit ripening. An example of the impact of 1-MCP on
tomato ripening is described in Table 7. Fruit at four
color stages (3.5, 4, 4.5 and 5; see color chart of ripen-
ing) were treated with 500ppb 1-MCP and then held at
15, 20 or 25°C (59, 68 or 77°F) to complete ripening.
SmartFresh® treatment substantially extended the time
to ripen and the impact was greater at lower tempera-
ture. The final firmness of the 1-MCP treated fruit can
be less than the respective control fruit since total
weight loss during ripening can be higher due to the
longer period necessary. Final red color was good in
all cases, except for some fruit stored at 25°C in which
red color development, especially of early ripening
fruit, was inhibited at this temperature. In numerous
tests we found that composition of ripe tomatoes was
similar in untreated and the 1-MCP treated fruit.
µl CO
2
/g-h
0
5
10
15
20
25
30
Days at 20°C from Breaker stage
024681012141618
nl C
2
H
4
/g-h
0
1
2
3
4
5
6
7
8
9
Ethylene Production
Respiration
T3
T5
T3rin
T3rin x T5
Figure 4. The respiration and ethylene production
rates of tomato fruits of conventional parent (T3, T5),
mutant (T3rin) and hybrid (T3rin x T5) breeding
lines.
Fruit Ripening & Ethylene Management Page 101
References
Baldwin, E.A., K. Goodner, and A. Plotto. Interac-
tion of volatiles, sugars, and acids on perception of
tomato aroma and flavor descriptors. J. Food Sci. 73:
S294-S307.
Cantwell, M.I. and R.F. Kasmire. 2002. Postharvest
Handling Systems: Fruit Vegetables. In: Postharvest
Technology of Horticultural Crops (A.A. Kader, ed.).
University of California Pub.3311, pp. 407-421.
Cantwell, M., G. Hong and X. Nie. 2009. Impact of
storage conditions on grape tomato quality. Acta Hor-
ticulturae, in press, 8pp. (http://
postharvest.ucdavis.edu/datastorefiles/234-1531.pdf).
Collins, J.K. and P. Perkins-Veazie. 2006. Lycopene:
from plants to humans. HortScience 41: 1135-1144.
Hobson, G. and D. Grierson. 1993. Tomato. In:
G.Seymour, J. Taylor and G. Tucker (eds.), Biochem-
istry of Fruit Ripening. Chapman & Hall, London. pp.
405-442.
Kader, A.A. 1984. Effect of postharvest handling pro-
cedures on tomato quality. Acta Hort. 190: 221.
Mir, N., N. Canoles, R. Beaudry, E. Baldwin, C. Pal
Mehla. 2004. Inhibiting tomato ripening with 1-
methycyclopropene. J. Amer. Soc. Hort. Sci. 121(1):
112-120.
Simmonne, A.H., B.K. Behe, M. M. Marshall. 2006.
Consumers prefer low-priced and high-lycopene-
content fresh-market tomatoes. HortTechnology 16:
675-681.
Table 1. Examples of differences in composition of different types of ripe tomatoes purchased at
supermarkets in Davis, CA in April (Cantwell, unpublished).
Tomato type Fruit
weight
g
Red
color,
Hue
Soluble
solids,
%
Sugar,
mg/mL
Titratable
acidity,
%
Vitamin C
mg/100g
Lyco-
pene
mg/kg
Campari 53.1 44.2 6.3 31.4 0.58 40.5 63.0
Cherry 20.3 45.5 4.2 28.9 0.31 54.0 84.6
Grape 5.0 51.3 5.6 29.5 0.51 47.1 49.1
Grape 6.2 41.7 4.2 39.6 0.35 61.7 98.0
Orange Cluster 111.5 71.5 4.6 26.1 0.33 29.2 4.2
Round Cluster 102.1 43.2 7.6 20.1 0.62 26.9 53.6
Round Cluster 119.8 44.6 3.8 15.3 0.44 26.0 44.8
Round Greenhouse 231.2 45.9 4.5 22.5 0.36 30.4 28.0
Round Greenhouse 179.4 47.7 4.7 25.0 0.44 20.4 42.5
Roma 94.8 42.1 4.3 24.0 0.27 22.8 46.4
Roma 84.5 45.2 6.2 20.2 0.67 24.3 44.4
Romanita 20.5 41.3 6.3 32.9 0.44 45.9 70.3
LSD.05 6.7 2.4 0.3 5.0 0.08 8.0 7.5
Fruit Ripening & Ethylene Management Page 102
Table 2. Maturity and ripeness classes for fresh market tomatoes.
Class Name USDA no. Description
Immature -- Seeds cut by a sharp knife; no jellylike material in any of the lo-
cules; fruit is more than 10 days from breaker stage
Mature-green
Mature green 1 1 Seeds fully developed and not cut on slicing fruit; jellylike material
in at least one locule; fruit is 6 to 10 days from breaker
Mature green 2 1 Jellylike material well developed in locules but fruit still com-
pletely green; fruit is 2 to 5 days from breaker; minimum harvest
maturity
Mature green 3 1 Internal red color at the blossom end, but no external red color;
fruit is 1 to 2 days from breaker stage
Breaker 2 First external pink or yellow color at the blossom end
Turning 3 More than 10 percent but not more than 50 percent of the surface,
in the aggregate shows a definite change in color from green to
tannish-yellow, pink or red, or a combination thereof
Pink 4 More than 30 percent but not more than 60 percent of the surface,
in the aggregate, shows pink or red color
Light red 5 More than 60 percent of the surface, in the aggregate, shows pink-
ish-red or red, but less than 90 percent of the surface shows red
color
Red 6 More than 90 percent of the surface, in the aggregate, shows red
color
Full Red - Fruit has developed full final red color
Table 3. Typical changes in color values and lycopene concentrations during ripening of conventional round
tomato fruits.
L* indicates lightness (high value) to darkness; a* denotes changes from green to red. Chroma and hue values
indicate vividness and color, respectively. As a tomato ripens and gets redder, the hue value decreases. A to-
mato with a hue value around 40 indicates full red color.
Stage of Develop-
ment Ripening
stage L* a* b* Chroma Hue Lycopene
mg/kg FW
Mature-Green 1 62.7 -16.0 34.4 37.9 115.0 0.1
Breaker 2 55.8 -3.5 33.0 33.2 83.9 0.4
Pink-Orange 4 49.6 16.6 30.9 35.0 61.8 8.6
Orange-Red 5 46.2 24.3 27.0 36.3 48.0 16.8
Red; Table-ripe 6 41.9 26.4 23.1 35.1 41.3 30.7
Dark Red; overripe 6+ 39.6 27.5 20.7 34.4 37.0 36.9
Fruit Ripening & Ethylene Management Page 103
Table 4. Effect of maturity at harvest on quality and composition of ripe grape tomatoes. Data average of 7
cultivars (Cantwell, 2003).
Firmness is force to compress fruit 5mm.
Initial
color
stage
Fruit
weight, g Red color
Hue Firmness,
N Soluble
solids, % Sugars
mg/mL Titratable
acidity, % Vitamin C
mg/100m
L
3 4.9 36.8 11.5 5.9 27 0.59 96
4 5.7 36.3 13.6 6.7 30 0.68 97
5 5.9 37.7 13.7 7.5 33 0.67 99
LSD.05 0.6 ns 1.5 0.8 3 0.08 ns
Table 5. Effect of temperature on average ripening of conventional round tomato fruits at mature-green,
breaker, turning and pink stages.
Days to Full red color at indicated temperature
Color Stage 12.5
55 15
59 17.5
64 20
68 22.5
72 25°C
77°F
Mature-green 18 15 12 10 8 7
Breaker 16 13 10 8 6 5
Turning 13 10 8 6 4 3
Pink 10 8 6 4 3 2
Table 6. Ripening and quality characteristics of round tomatoes of conventional and long shelf-life varieties.
Physiology of fruits within a category may vary greatly. Tomatoes were harvested at the breaker-turning stage
and ripened at 20°C (68°F). Data are averages from 40 conventional varieties and 25 long shelf-life varieties
(Cantwell, unpublished).
Characteristic Conventional Varieties Long shelf-life Varieties
Ripening physiology Average Range Average Range
Days from Breaker to table-ripe 6.3 5.3-7.3 7.8 6.0-9.8
Maximum respiration rate (µL CO2/g-h) 20.9 16.4-27.5 19.3 14.9-26.7
Maximum ethylene production rate (nl/g-h) 4.8 2.3-9.4 2.4 1.5-7.8
Color when ripe (Hue) 38.5 34.7-44.2 43.3 38.0-48.2
Composition
% soluble solids 4.5 4.1-5.1 4.5 4.0-5.1
% titratable acidity 0.33 0.28-0.45 0.38 0.30-0.49
Fruit Ripening & Ethylene Management Page 104
Table 7. Fruit weight, weight loss, days to table-ripe, firmness and red color of tomato (cv. Bobcat)
ripened at 15, 20 and 25°C (58, 68 and 77°F). Fruit received no treatment or 1-MCP (500 ppb) treatment at the
color stages indicated. Data averages of 3 reps of 8 fruit (Cantwell, unpublished)
Treatment Temperature Initial
color stage Weight
loss, % Days to ta-
ble-ripe Firmness,
N Red color,
Hue
Control 15°C (59°F) 3.5 1.7 16.4 25.9 34.6
4 1.3 15.1 26.2 35.5
4.5 0.8 13.9 27.9 35.0
5 0.2 8.2 25.9 34.9
1-MCP 15°C (59°F) 3.5 2.6 28.0 21.2 38.2
4 2.3 25.8 21.7 37.7
4.5 1.8 19.3 20.4 36.9
5 1.0 11.1 22.1 37.5
Control 20°C (68°F) 3.5 1.4 10.1 27.1 35.5
4 1.0 8.3 26.3 36.4
4.5 0.9 6.1 24.0 35.2
5 0.4 4.0 27.1 35.6
1-MCP 20°C (68°F) 3.5 3.0 25.8 21.7 38.2
4 2.9 18.8 18.4 37.3
4.5 2.4 14.8 16.7 36.5
5 1.0 8.3 20.9 37.6
Control 25°C (77°F) 3.5 2.4 9.6 22.8 42.4
4 2.1 8.3 25.0 36.0
4.5 1.8 6.2 24.1 35.1
5 0.9 3.0 25.5 35.3
1-MCP 25°C (77°F) 3.5 4.5 17.0 22.5 43.6
4 4.1 15.0 22.3 39.0
4.5 2.3 10.1 25.4 39.8
5 1.6 4.7 21.8 37.4
Control Average 15°C 3.5 1.0 13.4 26.5 35.0
Average 20°C 4 1.0 7.1 26.1 35.7
Average 25°C 4.5 1.8 6.9 24.4 37.2
1-MCP Average 15°C 3.5 1.6 21.0 21.3 37.6
Average 20°C 4 2.3 17.7 19.4 37.4
Average 25°C 4.5 3.1 11.7 23.0 40.0
LSD.05 0.3 0.4 3.2 1.9
Fruit Ripening & Ethylene Management Page 105
Tomato Maturity & Ripening Stages
GREEN The tomato surface is completely green. The shade
of green may vary from light to dark.
BREAKERS There is a definite break of color from green to
tannish-yellow, pink or red of 10% or less of the tomato
surface.
TURNING Tannish-yellow, pink or red color shows on over
10% but not more than 30% of the tomato surface.
PINK Pink or red color shows on over 30% but not more
than 90% of the tomato surface.
LIGHT RED Pinkish-red or red color shows on over 60%
but red color covers not more than 90% of the tomato surface.
RED Red means that more than 90% of the tomato surface,
in aggregate, is red.
http://www.californiatomatofarmers.org
http://floridatomatoes.org
1
2
3
4
5
6
Fruit Ripening & Ethylene Management Page 106
Trevor V. Suslow and Marita Cantwell
Department of Plant Sciences, University of California, Davis, CA 95616
Maturity Indices Standard Tomatoes. Minimum harvest maturity (Mature Green 2) is defined by
internal fruit structure indices. Seeds are fully developed and are not cut upon slic-
ing the fruit. Gel formation is advanced in at least one locule and jellylike material
is forming in other locules.
ESL* Tomatoes. Off-vine ripening is severely affected if fruit are harvested at the
MG2 stage. Minimum harvest maturity is better defined as equivalent to ripeness
class Pink (USDA Color Stage 4 more than 30 percent but no more than 60 percent
of the fruit surface, overall, shows a pink-red color).
* Extended Shelf-Life trait is due, in part, to either the presence of the rin or
nor gene.
Quality Indices Standard tomato quality is primarily based on uniform shape and freedom from
growth or handling defects. Size is not a factor of grade quality but may strongly
influence commercial quality expectations.
Shape. Well formed for type (round, globe, flattened globe, roma)
Color. Uniform (orange/red to deep red; light yellow). No green shoulders.
Appearance. Smooth and small blossom-end scar and stem-end scar. Absence of
growth cracks, catfacing, zippering, sunscald, insect injury, and mechanical injury
or bruises.
Firmness. Yields to firm hand pressure. Not soft and easily deformed due to an
overripe condition.
- U.S. grades are No. 1, Combination, No. 2, and No. 3. Distinction among
grades is based mainly on external appearances, bruising & firmness.
- Greenhouse grown tomatoes are graded as U.S. No. 1 or No. 2 only.
Optimum Mature Green 12.5- 15°C (55- 60°F)
Temperature Light Red (USDA Color Stage 5) 10- 12.5°C (50- 55°F)
Firm-ripe (USDA Color Stage 6) 7- 10°C (44- 50°F) for 3-5 days
Produce Facts
Tomato
Recommendations for Maintaining Postharvest Quality
Fruit Ripening & Ethylene Management Page 107
Optimum Mature-green tomatoes can be stored up to 14 days prior to ripening at 12.5°C
Temperature (55°F) without significant reduction of sensory quality and color development. Decay
is likely to increase following storage beyond two weeks, at this temperature. Typically
8-10 days of shelflife are attainable within the optimum temperature range after reach-
ing the Firm-ripe stage. Short term storage or transit temperatures below this range are
used by some in the trade but will result in chilling injury after several days. Extended
storage with controlled atmosphere has been demonstrated. (See Responses to CA)
Ripening 18-21°C (65-70ºF); 90-95% R.H. for standard ripening 14-16°C (57-61°F) for slow
Temperatures ripening (i.e. in transit). For more details on ripening conditions (see Ripening).
Chilling Injury Tomatoes are chilling sensitive at temperatures below 10°C (50°F) if held for longer
than 2 weeks or at 5°C (41°F) for longer than 6-8 days. Consequences of chilling in-
jury are failure to ripen and develop full color and flavor, irregular (blotchy) color de-
velopment, premature softening, surface pitting, browning of seeds, and increased de-
cay (especially Black mold caused by Alternaria spp.). Chilling injury is cumulative
and may be initiated in the field prior to harvest.
Optimum Relative 90-95%; High relative humidity is essential to maximize postharvest quality
Humidity and prevent water loss (desiccation). Extended periods of higher humidity or condensa-
tion may encourage the growth of stem-scar and surface molds.
Rates of Temperature 5°C (41°F) 10°C (50°F) 15°C (59°F) 20°C (68°F) 25°C (77°F)
Respiration ml CO2 / kg•hr
Mature-green 3-4NR 6-9 8-14 14-21 18-26
Ripening 7-8 12-15 12-22 15-26
To calculate heat production, multiply ml CO2 / kg•hr by 440 to get BTU/ton/day or by 122 to
get kcal/metric ton /day.
NR - not recommended for more than a few days due to chilling injury.
Ethylene 1.2 - 1.5µl/kg•hr at 10°C (50°F)
Production Rates 4.3 - 4.9µl/kg•hr at 20°C (68°F)
Responses to Tomatoes are sensitive to exogenous ethylene and exposure of mature-green
Ethylene fruit to ethylene will initiate ripening. Ripening tomatoes produce ethylene at
a moderate rate and co-storage or shipment with sensitive commodities, such as lettuce
and cucumbers, should be avoided.
Tomato
Fruit Ripening & Ethylene Management Page 108
Ripening Faster ripening results from higher temperatures between 12.5 -25°C (55-77°F); 90-
95% R.H.; 100 ppm ethylene. Good air circulation must be maintained to ensure
temperature uniformity within the ripening room and to prevent the accumulation of
CO2. CO2 (above 1%) retards the action of ethylene in stimulating ripening.
The optimum ripening temperature to ensure sensory and nutritive quality is 20°C
(68°F).Color development is optimal and retention of vitamin C content is highest at
this ripening temperature. Tomatoes allowed to ripen off-the-vine above 25°C (77°
F) will develop a more yellow and less red color and will be softer.
Ethylene treatment typically extends for 24-72 hours. A second treatment period
may follow repacking if immature green fruit were included in the harvest.
Responses to Controlled atmosphere storage or shipping offers a moderate level of benefit.
Controlled Low O2 levels (3-5%) delay ripening and the development of surface and stem-
Atmospheres (CA) scar molds without severely impacting sensory quality for most consumers. Storage
times of up to 7 weeks have been reported for tomatoes using a combination of 4%
O2, 2% CO2, and 5% CO. More typically, 3% O2 and 0-3% CO2 are used to main-
tain acceptable quality for up to 6 weeks prior to ripening. Elevated CO2 above 3-5
% is not tolerated by most cultivars and will cause injury. Low O2 (-1%) will cause
off-flavors, objectionable odors, and other condition defects, such as internal
browning.
Physiological Freezing Injury. Freezing injury will be initiated at -1°C (30°F), depending on the
Disorders soluble solids content. Symptoms of freezing injury include a watersoaked appear-
ance, excessive softening, and desiccated appearance of the locular gel. (See Chill-
ing injury.)
Field Disorders Tomatoes are sensitive to many production and environment-genetic interaction
disorders which may be manifested during postharvest ripening or postharvest in-
spection. Fertilizer and irrigation management, weather conditions, insect feeding
injury, asymptomatic virus infection, and unknown agents may interact to affect
postharvest quality. Examples are Blossom-end Rot, Internal White Tissue, Rain
Checking, Concentric and Radial Cracking, Puffiness, Persistent Green Shoulder,
and Graywall. Several references with photographic keys to disorders are available.
Reprinted from Horticultural Series #20, Produce Facts
Tomato POSTHARVEST TECHNOLOGY CENTER, UC Davis
http://postharvest.ucdavis.edu
  • ... Similar results were obtained by Mahajan et al. (2010) in ethrel treated banana fruits. The improvement in ripening of ethrel treated fruits is due to multifunctional nature of ethylene which coordinates expression of genes that are responsible for a variety of processes, including a rise in respiration and activities of ACC synthase and ACC oxidase, autocatalytic ethylene production and changes in color, texture, aroma and flavor (Kader and Mitcham 1994). Cost of ripening: Ripening cost was calculated as Rs. ...
    Article
    Full-text available
    Abstract: An experiment was carried out to investigate the effect of post harvest spray of different concentrations (100, 200, 400, 600 and 800 ppm) of ethrel (2-chloroethyl phosphonic acid) on ripening and colour development in ‘Dashehari’ mango fruits harvested in second week of June, 2015. The treated fruits were assessed for physico- chemical parameters such as physiological loss in weight (%), firmness (Kg/cm2 ), TSS (°Brix), titrable acidity (%), total carotenoids (mg/100g) and peel chlorophyll (mg/100g) and observations were recorded at 2 days interval dur- ing 8 days storage at ambient temperature. Changes in total soluble solids (8.5 to 23.23° Brix), total carotenoids (0.807 to 7.12 mg/100g) and PLW (14.58%) showed increasing trends up to 8 days during storage whereas fruit firmness (8.5 to 0.68 Kg/cm2 ), titrable acidity (1.26 to 0.08%) and total peel chlorophyll (5.2 to 0.14 mg/100g) showed decreasing trends. At the end of the storage period for 8 days, Ethrel spray at 600 ppm induced uniform ripening with attractive yellow colour within 4 days while untreated control fruits failed to ripen uniformly and remain light green even after 8 days of storage. Ripening advances by 4 days in fruits sprayed with 600 ppm ethrel com- pared to unsprayed control fruits.
  • ... Mango is a climacteric fruit and as such it can ripen after harvest, when harvested after its physiological maturity. However, fruits that ripen off the tree do not usually acquire their full flavour as those that ripen on the tree (Kader and Mitcham, 2008). Nevertheless, mango fruit are commonly harvested before full ripening to prolong the post-harvest storage period with minimal quality deterioration (Yahia, 1999). ...
  • ... Postharvest recommendations indicate that tomatoes should be stored at 10°C or higher to avoid chilling injury (Roberts et al., 2002) and even 10°C may be detrimental to tomato flavor quality (Maul et al., 2000). Chilling injury symptoms include failure to ripen which develop full color and flavor, irregular color development, excessive softening, surface pitting, and increased decay (Cantwell, 2010;Sargent and Moretti, 2004). ...
    Article
    Full-text available
    Postharvest losses in tomatoes are not only quantitative but also qualitative losses which directly can have a negative impact on consumer’s preference, nutritional quality and income of producers. Therefore, it is important to identify factors that can affect the postharvest quality and antioxidant composition of tomatoes. Tomato quality is an outcome of several factors including cultivar selection, environmental conditions where it grows and preharvest practices carried out during production. Preharvest practices carried out during production that affect the postharvest quality need to be considered thoroughly. Harvesting at proper maturity stage and ripening conditions are critical and must be carefully established for each cultivar. Knowledge of preharvest factors that affect the quality and antioxidant composition of tomato fruits and acquiring the skill of management can play a role on the production of best quality fruits at harvest, which in turn directly affect postharvest quality and nutritional composition. Therefore, it is of great significance to know the preharvest factors that can help to produce superior quality tomato fruits and equally important to use proper postharvest handling and management technologies, to maintain the quality and nutritional composition of the fruits after harvest. This review is therefore conducted to emphasize on some preharvest and postharvest factors that can affect the postharvest qualities, antioxidant properties and shelf life of tomatoes. Key words: Antioxidant activity, ascorbic acid, environmental factors, lycopene, storage.
  • ... Xudong et al. (2009) assert that fruit and vegetable maturity influences market value, transportation and storage requirements. Thus, it is important for individuals harvesting fruit to have effective methods of determining maturity (Kader and Mitcham, 2008). ...
  • ... As the use of calciurn carbide is prohibited in India due to health reasons (PFA 2003), an alternative ofthis chernical is required. In this direction, ethylene gas and ethephon chemical have been found to accelerate the ripening of mature green tomato fruits and has already been used comrnercially in other courrtries for unifornt and early ripening of torratoes (Kasnrire l98l ; Cantwell 1994: Gonzalez 1999: Sargent 2005. But in tndian context. ...
    Article
    Full-text available
    The present studies were conducted to obtain information about the effect of ethephon and ethylene gas on ripening and quality of winter tomato (Solanum lycopersicum L.) using hybrid Avinash-3. The first experiment comprised of treatment of mature green tomatoes with different concentrations of aqueous solution of ethephon (500, 1000 and 1500 ppm) for 5 minutes. The fruits were packed in plastic crates and kept in storage room at 20±1oC and 90-95% RH. The second experiment comprised of exposing the mature green tomatoes to ethylene gas (100 ppm) inside the ripening chamber for 24 hours (20±1oC and 90-95% RH) and thereafter kept in the ripening chamber maintained at 20±1oC and 90- 95% RH. The one lot of fruits was not treated and kept as control. The physico-chemical parameters of fruits from mature green to senescent stage of maturation were analyzed. The ethylene gas (100 ppm) treatment registered the highest ripening percentage. The ripening and rotting percentage increased with increase in the concentration of ethephon (500-1500 ppm) and with the duration of days for which the fruits were kept for ripening. The titratable acidity of tomato fruits experienced a linear decline but ascorbic acid and lycopene content registered an increase with the advancement of ripening period irrespective of any treatment. The tomato fruits harvested at green mature stage get successfully ripened in 9 days with application of ethephon (500, 1000, 1500 ppm) but the rotting was more than 14 per cent till 9th day in Hybrid-1001 which makes fruits unmarketable. Therefore, the application of ethephon for ripening is not a good option. Treatment with ethylene gas (100 ppm) resulted in adequate ripening of fruits after 9 days with uniform red colour, desirable firmness, minimum rotting and acceptable quality and therefore this treatment is better over ethephon. In control fruits similar results of ripening, firmness, rotting and quality were observed as in case of ethylene gas (100 ppm) treatment but the fruits get longer time (11 days) to uniformly ripen.
  • ... T2 fruits showed the increasing of TSS when the diameter of the fruits increased. The increased TSS gradually occurred with the advancement of ripening process (Cartwen 2000, Moneruzzaman et al. 2008. The percentage of TSS recorded in all treatments relatively higher compared to the commercial production. ...
    Article
    Full-text available
    The experiment consisted of five treatments of fermented plant juice (FPJ) and fermented fruit juice (FFJ). The treated plants with FPJ and FFJ produced early flowers and fruits compared to untreated plants due to the enhanced production of auxin and essential nutrients. Total soluble solids were also observed to increase after 10 weeks of FPJ and FFJ application. Photosynthesis rate increased in all treatments except T3; while transpiration rate increased only at T4 compared to control. The findings we clearly suggested to use both combinations as FPJ water spinach for enhancing the vegetative growth of tomato plants than FPJ bamboo shoots (T3 and T5), while FFJ pineapple for better reproductive development of tomato plants rather than FFJ banana (T5) for ensuring future sustainable eco-friendly agriculture practices.
  • ... However, the lowest ripening percentage was recorded in control fruits, which ranged from 30.8 to 62.4% between 3 and 7 days. Better performance of ethylene in ripening of tomato may be due to the fact that ethylene is undoubtedly considered as the most multifunctional plant hormone, which triggers the respiration rate leading to dramatic changes during the ripening process, ensuring faster and uniform ripening (Cantwell, 1994;Sargent, 2000) There were significant differences among the various ripening treatments with regard to physiological loss in weight (PLW) (Table 1), which, in general increased during the ripening period and resulted in the highest mean PLW (6.5%) on the 7 th day as compared to the 3 rd day (1.6%). On the other hand, the ethephon (1000 ppm for 10 min) treated fruits registered the highest mean PLW (5.3%) and the lowest was in the control (2.6%). ...
    Article
    Full-text available
    Fruits of a winter tomato (Lycopersicum esculentum L.) hybrid were harvested at mature green stage and a first lot was exposed to ethylene gas (100 ppm) for 24h in a ripening chamber at 20±1°C and the second lot was treated by immersion in a solution of ethephon {(2-chloroethyl) phosphonic acid} at 2 different concentrations (500 and1000 ppm) and for two different lengths of times (5 and 10 min). The fruits were air dried and placed in plastic crates followed by storage in a ripening chamber at 20±1°C and 90-95% RH. The colour, texture and flavour parameters of fruits from mature green to senescent stage of maturation were analyzed. The most striking effect of treatment was on colour development of fruits. It was found that treatment with ethylene gas (100 ppm) for 24h inside the ripening chamber or immersion in ethephon solution (500 ppm) resulted in better ripening of tomato fruits with uniform red colour, desirable firmness and acceptable quality as compared to other treatments. The length of time of the ethephon dip treatment did not reveal any significant effect on colour development. The fruits in the control showed very poor ripening and were hard in texture with poor quality attributes.
  • ... Tomatoes, including cherry and grape tomatoes, should be stored at 10°C or higher to avoid chilling injury (Jimenez et al., 1996; Roberts et al., 2002), and even 10°C may be detrimental to tomato flavor quality (Maul et al., 2000). Chilling injury symptoms include failure to ripen and develop full color and flavor, irregular color development, excessive softening, surface pitting, and increased decay (Cantwell, 2008; Sargent and Moretti, 2004; Suslow and Cantwell, 2000). With small fruited tomato cultivars, weight loss and symptoms of shrivel become important quality parameters, and lower storage temperatures can mitigate this quality problem (Cantwell et al., 2009). ...
    Article
    Full-text available
    Grape and cherry tomatoes comprise about one quarter of retail tomato sales in the United States and are also important components in fresh-cut mixed vegetable trays. The latter require low temperatures and packaging which can produce a range of modified atmospheres (MA) to achieve 14 days of shelf-life. Postharvest handling recommendations for good tomato quality do not usually include low temperatures or MA. Storage studies were conducted to ascertain the effect of low temperatures and MA on grape tomato quality. Grape tomatoes (orange-red or more advanced color) can be stored in clamshells for up to 18 days at 5°C and still be of marketable quality if kept cold. Continuous storage at 5°C in air resulted in minimal weight loss (a significant cause of quality loss in grape tomato stored at warmer temperatures), and retention of vitamin C levels, but no lycopene synthesis, and decreased sugar concentrations. However, if fruit were transferred from 5 or 10°C to warmer temperatures (i.e., 20°C), typical chilling injury symptoms (decay, poor color formation) occurred on fruit stored at 5°C but not at 10°C. Controlled atmospheres (CA) of 3 or 10% O2 with 0, 7, 12 or 18% CO2 provided little or no benefit, but were tolerated by grape tomatoes for up to 21 days at 5°C. These results are based on evaluation of visual appearance, discoloration, decay, aroma, off-odors, flavor, and changes in concentrations of lycopene, sugars, vitamin C, ethanol and acetaldehyde. Although not ideal, near-ripe high quality grape tomatoes perform well as components of fresh-cut vegetable trays at low temperatures and under atmospheres not usually recommended for tomatoes.
  • Conference Paper
    Most of the research about this topic is the way to delay ripening by modified atmosphere packaging using edible films or by inhibiting ethylene action through the use of 1-methylcyclopropene (1-MCP).
  • Article
    Mango (Mangifera indica L.) quality is strongly influenced by genotype but individuating the most appropriate harvesting time is essential to obtain high quality fruits. In this trial we studied the influences of the ripening stage at harvest (mature-ripe or green-ripe) on quality of ready to eat mango fruits from nine cultivars (Carrie, Keitt, Glenn, Manzanillo, Maya, Rosa, Osteen, Tommy Atkins and Kensington Pride) grown in the Mediterranean subtropical climate through physicochemical, nutraceutical, and sensory analysis. Our results show a large variability among the different observed genotypes and in dependence of the ripening stage at harvest. With the exception of Rosa, mature-ripe fruits are well-colored, sweet and aromatic, and better suited for short supply chains. On the other hand, post-harvest ripened fruits are firmer, frequently (Carrie, Glenn, Keitt, Manzanillo, Maya) possess interesting nutraceutical value and, in the case of Glenn, Maya, Osteen, and Kensington Pride, they can reach market standard quality.
  • Postharvest Handling Systems: Fruit Vegetables University of California Pub
    • M I Cantwell
    • R F Kasmire
    Cantwell, M.I. and R.F. Kasmire. 2002. Postharvest Handling Systems: Fruit Vegetables. In: Postharvest Technology of Horticultural Crops (A.A. Kader, ed.). University of California Pub.3311, pp. 407-421.
  • Book
    Introduction - G A Tucker Avocado - G B Seymour and G A Tucker, Banana - G B Seymour Citrus fruit - E A Baldwin Exotics - J E Taylor Grape - A K Kanellis and K A Roubelakis-Angelakis Kiwifruit - N K Given (deceased) Mango - C Lizada Melon - G B Seymour and W B McGlasson Pineapple and papaya - R E Paull Pome Fruit - M Knee Soft fruit - K Manning Stone fruit - C J Brady Tomato - G Hobson and D Grierson. Index.
  • Article
    Full-text available
    Storage and ripening recommendations for tomatoes are well known, but quality problems associated with poor temperature management continue to occur during distribution. Grape and cherry tomatoes, also called 'snacking' tomatoes, now constitute about 24% of the value of all tomatoes sold in U.S. supermarkets. New marketing opportunities, such as grape tomatoes in trays of fresh-cut vegetables, expose fruit to temperatures of 5°C or below often in combination with modified atmospheres, conditions at odds with postharvest recommendations for good tomato quality. Several studies were conducted on different varieties of grape tomatoes. 1-MCP only slightly retarded ripening and delays to cool affected subsequent color and water loss. Storage at 10°C resulted in excellent quality fruit. At 5°C, near ripe grape tomatoes were of marketable quality for 18 days. Storage at 5°C resulted in minimal weight loss, no lycopene synthesis, decreases in sugar concentrations and retention of Vitamin C concentrations. However, if fruit were transferred from 5°C to warmer temperatures, typical chilling injury symptoms (decay, poor color formation) occurred. Controlled atmospheres of 3 or 10% oxygen with 0, 7, 12 or 18% carbon dioxide at 5°C provided little benefit but were tolerated by grape tomatoes for up to 3 weeks based on visual appearance, discoloration, decay, off-odors, and changes in composition (sugars, Vitamin C, and ethanol and acetaldehyde concentrations). Although not ideal, near ripe high quality grape tomatoes do perform well as components of fresh-cut vegetable trays at low temperature under controlled atmospheres not recommended for tomatoes.
  • Article
    Full-text available
    Fresh and processed tomato (Lycopersicon esculentum) consumption has increased 40% in the United States over the last two decades. Through better breeding, fresh tomatoes now are marketed in different forms, sizes, colors, and flavors. However, little published information exists concerning consumer demand, preference, and demographic characteristics related to fresh tomato consumption. Taking advantage of a high percentage of Internet use in the U.S., two web-based surveys were released to approximately 6000 e-mail addresses reaching people in every region of the U.S. The surveys contained a total of 61 questions, including 50 digital images of five types of tomatoes (cherry, grape, cluster, plum, and regular slicing) with combinations of three additional factors (price, lycopene content, and production style) and demographic information. Among 389 respondents, 76% preferred and purchased slicing tomatoes in the 4 weeks prior to the survey. These were followed by grape/mini-pear (42%), plum (36%), cluster (27%), cherry (25%), and yellow slicing tomatoes (4.4%). Overall, production method (organic vs. conventional) had low relative importance in comparison to price and tomato type. However, younger participants (<age 38 years) placed more importance on production method. Participants between ages 39 and 57 years were the most price-sensitive, and female were less sensitive than males. Younger participants (<age 38 years) were less price-sensitive and placed more importance on the other attributes (production method, lycopene content, and tomato type).
  • Article
      To better understand the effect of sugars and acid levels on perception of aroma volatiles, intensity of tomato earthy/medicinal/musty, green/grassy/viney, and fruity/floral aroma and flavor descriptors were evaluated using coarsely chopped partially deodorized tomato puree. This puree was spiked with 1.5% to 3% sugar (glucose/fructose combinations), 0.1% to 0.2% acid (citric/malic acid combinations), or water and 2 levels of 12 individual food-grade volatiles reported to contribute to tomato flavor. A panel consisting of 6 to 8 trained members rated 9 aroma, 8 taste, and 1 aftertaste descriptors of the spiked and nonspiked purees. The panelists detected significant differences (P≤ 0.1) for various individual aroma compound/sugar/acid combinations for a range of descriptors. Adding 0.2% acids alone to bland tomato puree decreased green and floral aromas as well as sweet taste. Adding 3% sugars alone increased green and musty aromas and decreased floral aroma as well as sour, citrus, and bitter tastes. Principal component analysis (PCA) explained 56.5% of the variation in the first 3 principal components (PCs) for added acids and volatiles to bland tomato puree. The effect of added acids with the various aroma compounds generally increased perception of overall and ripe tomato taste and aroma, tropical aroma, and sour taste, and decreased sweet, fruity, and bitter tastes. PCA for added sugars with volatiles explained 67.8% of the variation in first 3 PCs, and sugars generally decreased perception of sour, bitter, and citrus tastes and green aroma, while enhancing perception of flavors associated with ripe, tropical, and aromatic tomatoes. Adding sugars, acids, and volatiles together had a similar effect to addition of sugars alone.
  • Article
    Full-text available
    The capacity for 1-methylcyclopropene (1-MCP) to inhibit color change and firmness loss and alter aroma profiles for tomato (Lycopersicon esculentum Mill.) fruit was evaluated as a function of 1-MCP concentration, multiple and continuous applications, and stage of ripeness. In addition, the relationship between external and internal fruit color and firmness was determined. 1-MCP reduced the rate of red color development in fruit of all stages of ripeness. A single application of 1-MCP delayed color development by approximately equal to 6 days. A second application of 1-MCP 10 days after first treatment additionally delayed color development of mature green fruit by another 8 to 10 days. Continuous 1-MCP application completely inhibited color development of breaker and half-ripe fruit for the duration (34 days) of application, but only partially inhibited firmness loss. When fruit at 50% color development were treated with 1-MCP, gel color development tended to lag behind the external fruit color change compared to nontreated fruit. Some aroma volatiles were affected by 1-MCP applied at the mature green and breaker stages, but the effect was relatively minor; 1-MCP did not affect sugar or titratable acid levels in these fruit. Collectively, the data indicate 1-MCP caused minor shifts in the quality attributes of locule color, aroma, and firmness relative to external color, which may reduce the value of this treatment, but benefits accrued by slowed firmness loss and color development may afford sufficient compensation to make 1-MCP application commercially feasible.
  • Article
    Lycopene is a pigment that imparts a red or red-orange color to some fruits and vegetables. This carotenoid has been extensively studied over the last 10 years because of its potent antioxidant activity and medical evidence that dietary intake can reduce the incidence of cardiovascular disease and some cancers. The purpose of this review is to provide researchers in the areas of horticulture and food science a current summary of available information on lycopene in plants, stabilization and extraction, and potential health benefits as delineated in current medical studies.