Mechanical and Temperature Effects on Shelf Life Stability of Fruits and Vegetables - Food Shelf Life Stability: Chemical, Biochemical, and Microbiological Changes - page 67

its quality is impaired and shelf life is shortened as the injury itself is irreversible.
Sanford and co-workers 173 reported that weight loss and the incidence of shriveling
or splitting in lowbush blueberries are major attributes that contribute to the loss of
market value arising from mechanical damage and too low a storage temperature.
Ballinger and co-workers 174 recommended that for the fresh market, blueberries
should not be exposed to temperatures exceeding 10°C and should be preferably
kept at or near 1°C. The major qualitative characteristics that contribute to low
commercial yield of fruits are loss of firmness, loss of bloom, and loss of the blue
anthocyanin coloration either through leakage from the berry or chemical disruption
of the pigment. 173 Sanford and co-workers 173 found 0°C storage to result in optimum
conditions of the product.
Short storage life is a problem in raspberries due to their fragile structure and
rapid deterioration. Even under recommended storage conditions of -0.5 to 0°C,
and 90 to 95% relative humidity, usual shelf life is only 2 to 3 days with a maximum
of 1 week. 54 Robbins and co-workers 175 tried to extend the shelf life of red raspberries
beyond what was reported by careful attention during harvesting, immediate pre-
cooling for 4 h at 0°C and subsequent storage at 0°C and 90 to 95% relative humidity.
Harvesting at the red-ripe stage also extended the storability of the fruit. Robbins
and Moore 176 recommended a storage temperature of 0°C for maintenance of color.
It is also preferred for short storage periods to preserve other quality characteristics
such as firmness and flavor components. A temperature between 12 and 13°C is
generally considered optimum for storage of mangos, 177 although suitable tempera-
tures such as 10°C and 5°C were also given depending on maturity, ripeness, and
cultivar. Medlicott and co-workers 136 reported that storage at 12°C caused limited
ripening of the fruits, whereas storage at the higher temperature of 25°C caused no
detrimental effect on full ripening after 21 days of storage. On the other hand,
Campbell and co-workers 178 reported that carambolas (var. “Arkin” and “Golden
Star”) can be successfully stored at 5°C for at least 3 weeks without significant
changes in soluble solids, weight, or organic acid concentration. The relative humidity
of the storage should be kept between 85 to 90% to reduce water loss and prevent
shriveling. 74 Rewarming the fruit at 23°C after storage for 6 days may still induce
normal ripening without chilling injury.
A PPROPRIATE T RANSPORT
The following suggestions for transporting fresh produce have been recommended
by FAO 1 to minimize heat accumulation and losses due to increased respiratory
activity: (1) in transporting fresh produce, closed vehicles without refrigeration
should not be used except for local deliveries; (2) open-sided or half-boarded trucks
can be fitted with a roof or canvass roofing and siding to protect the produce from
the sun and wind; (3) a second white painted roof may be fitted 8 to 10 cm above
the main roof to act as radiation shield; (4) for long-distance travel, vehicles without
refrigeration should have elaborate air intakes which can be fitted in conjunction
with louvers to ensure positive airflow through the load; and (5) transport vehicles
like trucks, rail cars, and sea containers should be equipped with refrigeration for
long journeys. In Table 2.8 , fruits are grouped for compatible refrigerated transport.