Postharvest Physiology and Storage - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 16

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Postharvest Physiology and Storage

Marta Montero-Calder on and Marıa de Milagro Cerdas-Araya

INTRODUCTION
Fruits are plant-living organs with a series of ongoing
physical, chemical, biochemical, and sensorial attributes
changes as they grow, develop, and ripen. When the fruit
is harvested, water and nutrients supplied from the plant
are interrupted, but respiration and other metabolic reac-
tions continue. The type and rate of changes vary with the
fruit type, cultivar, and maturity stage, among others, but
it is also affected by external factors such as temperature,
relative humidity, atmosphere composition, light, and the
response to mechanical, microbiological, and physiological
stresses during pre- and postharvest handling of the fruit.
Proper selection of harvesting time and further handling
operations are important to preserve the fruit quality at-
tributes at a maximum level until they reach either the
processing plant or the fresh market consumers.
In most cases, fruits require to be stored before process-
ing, for a few hours, days, weeks, or even months, because
of production peaks and long distances from the growing
areas to the processing plants. These highlight the need of
a good understanding of the response of the fruit to han-
dling and storage conditions, related to the quality attributes
needed for preparation of the final processed food.
Changes include variations in internal and external color,
texture, appearance, flavor, aroma, and nutritional proper-
ties which could be desirable or not, depending on the final
use of the fruit.

include some floral parts. Individual fruits may be formed
from a single and enlarged ovary (i.e., avocado, peach,
apple, orange), multiple ovaries belonging to a single flower
(aggregate fruit such as strawberries, raspberries, and figs),
or enlarged ovaries of several flowers including accessory
floral parts fused together to form the fruit (aggregated
fruits like pineapples).
The edible part of a fruit can be derived from different
types of tissues as they develop to become the flesh part of
the fruit; some examples are shown in Table 2.1.
The large variability of tissue types from which the fruits
are developed reveals the expected differences in the fruit
postharvest behavior, respiration rates, and the difficulty
to classify these products in a single way which could ex-
plain the internal changes of the fruit during ripening and
storage; however, grouping of fruits with similarities to
growing area, handling procedures, or other attributes is
very convenient (Wills et al., 1999). In that sense, they can
also be classified as temperate, subtropical, and tropical
fruits, depending on the region where they originated and
are produced.
As the fruit grows and develops, a series of changes oc-
cur: immature tissues generally have a firm texture with
discrete green colors in the skin and pale neutral colors
in the interior; as the fruit ripens, the firmness decreases
and the fruit becomes more bright and attractive for con-
sumption, as pigmentation changes and flavor and aroma
develop.
Fruit characteristics largely vary among fruits, in their ex-
ternal and internal appearance as well as in their structure,
composition, metabolic activity, and response to external

Fruits: types and classification
According to Kays (1997), the term fruit in botany refers
to a mature ovary that contains one or more seeds and may