Biomedical Engineering Reference
In-Depth Information
TABLE 2.7 (continued)
Safe Storage Temperature, Symptoms, and Amelioration of Chilling Injury
in Fruits and Vegetables
Approx. Lowest
Commodity
Safe Temp. °C
Symptoms of Chilling Injury
Amelioration
Pumpkins
10
107
Decay
107
12.8-15.6
119
Sweet peppers
7
107
Pitting,
Alternaria
rot
107
6.5
121
Sweet potato
13
107
Internal discoloration, pitting,
decay
107
cv. Kokei No.14
8.5
121
Taro
13-15
128
Tomatoes: mature
green
13
107
9.5
121
5.5
121
13
107
Water-soaked softening, decay,
Alternaria
rot
107
Pre-storage high
temperature
conditioning
130
Intermittent warming
131
cv. Beiju dark
pink
cv. Beiju ripe
Ya m
Poor color, abnormal ripening
107
1 3 - 1 5
128
I
NCIDENCE OF
H
IGH
T
EMPERATURE
I
NJURY
High temperature injury occurs when the packaged produce is exposed to the sun
while awaiting transport to the packinghouse; during retail in open markets; when
the produce comes in contact with a heated surface; when the produce is packed or
transported with lack of cooling and ventilation; and when the produce is subjected
to heat treatment for disinfection. An and Paull
141
reported that papayas stored at
32.5°C for 10 days failed to ripen normally, as observed by poor color development,
abnormal softening, surface pitting, and occasional off-flavor. On the other hand,
fruits stored at 10°C for 14 days exhibited faster ripening rates as evidenced by
degreening and softening of the flesh, and no delay in flesh color development. At
temperatures above 25°C, banana skin remains greenish but the pulp becomes mushy
and has poor flavor.
125
Storage temperatures above 30°C may result in the failure of tomatoes to ripen
normally. Color development of tomatoes arises from lycopene synthesis. Failure to
synthesize lycopene often occurs during wholesale and retail operations in tropical
countries. Temperatures above 30°C inhibit the synthesis of lycopene and most other
polyene pigments but not the synthesis of beta-carotene which is responsible for the
yellow color.
142
Ripening and ethylene production are suppressed and heat injury
may result when tomatoes are stored at 40°C and scald develops at the stem end of
the fruit. At temperatures above 30°C, respiratory metabolism is altered and Inaba
and Chachin
143
postulated that this may be associated with changes in membrane
properties, which ultimately lead to heat injury at 40°C. Abnormal ripening of
tomatoes after transferring to 25°C may occur, since thermal stress accumulates on
the fruit and consequently, it alters the mitochondrial properties after 4 to 5 days at
35°C. Sub-optimal temperature during storage will also lead to similar effects.
144
In
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